Alpha-type silon phosphor and light-emitting device

Abstract

An α-type silon phosphor, which is composed of the general formula (Ca x Eu y (Si) 12‑(m+n) Al m+n (O) n N 16‑n This indicates that the average linear expansion coefficient α′ in the range of 25–900℃ is above 4.2 ppm / ℃ and below 4.6 ppm / ℃. In the general formula, 0 < x < 2.0, 0 < y ≤ 0.5, 0.3 ≤ x + y ≤ 2.0, 0 < m ≤ 4.0, and 0 < n ≤ 3.0.

Description

Technical Field

[0001] This invention relates to an α-type silon phosphor and a light-emitting device. Background Technology

[0002] Alpha-type silon phosphors, formed by activating rare-earth elements such as Eu, can efficiently convert blue light into longer wavelengths. Therefore, they are suitable for wavelength conversion components, for example, in white LEDs.

[0003] In α-type silicon phosphors, the Si-N bonds in typical α-type silicon nitride crystals are replaced by Al-N and Al-O bonds. To maintain electroneutrality, they possess a structure where specific elements (Ca, as well as Li, Mg, Y, or lanthanides other than La and Ce) are infiltrated and dissolved within the crystal lattice. By making a portion of the infiltrated element a rare-earth element that serves as the luminescence center, fluorescence properties are exhibited. Specifically, α-type silicon phosphors with Ca dissolved and partially replaced by Eu are relatively efficiently excited in a broad wavelength region from ultraviolet to blue, exhibiting yellow or orange luminescence.

[0004] To further improve the fluorescence properties of α-type silon phosphors, various attempts have been made (e.g., patent documents 1-3, etc.).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2009-96882

[0008] Patent Document 2: Japanese Patent No. 6667025

[0009] Patent Document 3: Japanese Patent No. 6785333 Summary of the Invention

[0010] With the increasing popularity of white LEDs, the performance requirements for α-type silon phosphors are becoming more and more stringent.

[0011] The inventors conducted various studies in order to obtain an α-type silon phosphor with the improved luminescence properties described in this study.

[0012] The inventors have completed the invention described below through various studies.

[0013] 1. An α-type silon phosphor, represented by the following general formula, having an average linear expansion coefficient α′ of 4.2 ppm / ℃ or higher and 4.6 ppm / ℃ or lower at 25–900 °C.

[0014] General formula: (Ca x Eu y (Si) 12-(m+n)Al m+n (O) n N 16-n ),

[0015] In the general formula, x, y, m, and n satisfy the following:

[0016] 0 < x < 2.0;

[0017] 0 < y ≤ 0.5;

[0018] 0.3≤x+y≤2.0;

[0019] 0 < m ≤ 4.0;

[0020] 0 < n ≤ 3.0.

[0021] 2. The α-type silon phosphor according to 1, wherein,

[0022] 2.5≤m≤4.0, 0<n≤0.5.

[0023] 3. The α-type silon phosphor according to 1. or 2, wherein,

[0024] When the average linear expansion coefficient at 25–300℃ is set as α1′ and the average linear expansion coefficient at 700–900℃ is set as α2′, α2′ / α1′ is 1.3–1.8.

[0025] 4. The α-type silon phosphor according to any one of 1 to 3, wherein,

[0026] At 25°C, the lattice constant a of a unit crystal lattice 25 for The above and The following is the lattice constant c 25 for The above and the following.

[0027] 5. The α-type silon phosphor according to any one of 1 to 4, wherein,

[0028] At 25°C, the lattice volume V of a unit crystal lattice 25 for The above and the following.

[0029] 6. The α-type silon phosphor according to any one of 1 to 5, wherein,

[0030] In the general formula, x, y, m, and n satisfy the following:

[0031] 1.3 ≤ x < 2.0;

[0032] 0.01≤y≤0.1;

[0033] 1.3 ≤ x + y ≤ 2.0;

[0034] 2.8 ≤ m < 4.0;

[0035] 0.1≤n≤0.27.

[0036] 7. A light-emitting device comprising:

[0037] Light-emitting elements; and

[0038] The wavelength conversion section includes any one of the α-type silon phosphors described in 1 to 6, and converts the light emitted from the light-emitting element to a longer wavelength.

[0039] According to the present invention, an α-type silon phosphor with improved luminescence properties is provided. Attached Figure Description

[0040] Figure 1 This is a schematic cross-sectional view illustrating the structure of a light-emitting device. Detailed Implementation

[0041] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0042] The accompanying drawings are for illustrative purposes only. The shapes or dimensions of the parts in the drawings may not necessarily correspond to actual objects.

[0043] In this specification, the expressions "X~Y" in the description of numerical ranges, unless otherwise specified, mean above X and below Y. For example, "1~5% by mass" means "more than 1% by mass and less than 5% by mass".

[0044] <α-type silon phosphor>

[0045] The α-type silon phosphor in this embodiment is represented by the following general formula.

[0046] General formula: (Ca x Eu y (Si) 12-(m+n) Al m+n (O) n N 16-n )

[0047] In the above general formula, x, y, m and n satisfy the following.

[0048] 0 < x < 2.0

[0049] 0 < y ≤ 0.5

[0050] 0.3 ≤ x + y ≤ 2.0

[0051] 0 < m ≤ 4.0

[0052] 0 < n ≤ 3.0

[0053] Furthermore, the average linear expansion coefficient α′ of the α-type silon phosphor in this embodiment is 4.2 ppm / ℃ or more and 4.6 ppm / ℃ or less at 25 to 900 °C.

[0054] The α-type silon phosphor of this embodiment exhibits excellent luminescence properties. Although the reason for this is not yet clear, it can be inferred that the α-type silon phosphor of this embodiment has a crystal structure that readily and efficiently emits fluorescence, based on the fact that m and n are within a specific numerical range in the above general formula and that the coefficient of thermal expansion is considered an indicator that can be related to the crystal structure.

[0055] In this embodiment, the average linear expansion coefficient α′ can be determined, for example, by measuring and analyzing the temperature-lattice constant relationship, as shown in the following [example of the steps for determining the average linear expansion coefficient α′]. For detailed calculation methods, please refer to the embodiments described later.

[0056] [An example of the steps to calculate the average linear expansion coefficient α′]

[0057] (1) X-ray diffraction measurements of α-type silon phosphors were performed at several points within a temperature range of 25–900 °C.

[0058] (2) Based on the X-ray diffraction results, determine the lattice constant of the crystal in the phosphor at each temperature T. In the case of an α-type silron phosphor, determine the lattice constant α at each temperature T. T and c T Incidentally, in the crystal structure of α-type silron, the lattice constant b of the unit lattice is... T Become with a T Same value.

[0059] (3) Temperature T-lattice constant a were plotted separately. T Temperature T - lattice constant c T The graphs are then used. Then, the approximate linear form for each graph is determined. The approximate linear form can be determined using the least squares method.

[0060] (4) Read the lattice constant a at 25℃ from an approximate straight line. 25 and c 25 And the lattice constant a at 900℃ 900 and c 900 Substitute these values ​​into V in Formula 1 below. 25 The formula and V 900 From the formula, the lattice volume V at 25℃ is calculated. 25 and the lattice volume V at 900℃900 Then, the volume expansion coefficient β is calculated according to the following formula 2.

[0061] [Number 1]

[0062] Formula 1

[0063]

[0064] [Number 2]

[0065] Formula 2

[0066] V 900 =V 25 ·(1+βΔT)

[0067]

[0068] (5) Calculate the average linear expansion coefficient α′ using the formula α′=β / 3. Incidentally, the formula α′=β / 3 is used to calculate the average linear expansion coefficient as a polycrystalline material, assuming the sample is isotropic.

[0069] In addition to using appropriate amounts of appropriate raw materials, the α-type silon phosphor of this embodiment can also be manufactured by employing appropriate manufacturing conditions.

[0070] Regarding "using appropriate amounts of appropriate raw materials", examples can be given of adjusting the amount of raw materials in a way that satisfies the aforementioned general formula x, y, m, and n.

[0071] Regarding "appropriate manufacturing conditions," examples include the "annealing process" in a non-reactive gas environment such as nitrogen and the "hydrogen annealing process" in a hydrogen environment, which will be described in detail later. By employing appropriate manufacturing methods / conditions, the α-type silon phosphor of this embodiment can be manufactured. Conversely, without employing appropriate manufacturing methods / conditions, even with the use of appropriate amounts of appropriate raw materials, it is sometimes impossible to obtain the α-type silon phosphor of this embodiment.

[0072] The α-type silon phosphor of this embodiment will continue to be described.

[0073] (Regarding the general formula: (Ca) x Eu y (Si) 12-(m+n) Al m+n (O) n N 16-n ))

[0074] x only needs to satisfy 0 < x < 2.0, preferably 1.0 ≤ x < 2.0, and more preferably 1.3 ≤ x < 2.0.

[0075] y only needs to satisfy 0 < y < 0.5, preferably 0.01 ≤ y ≤ 0.1.

[0076] x + y only needs to satisfy 0.3 ≤ x + y ≤ 2.0, preferably 1.0 ≤ x + y ≤ 2.0, and even more preferably 1.3 ≤ x + y ≤ 2.0.

[0077] m only needs to satisfy 0 < m ≤ 4.0, preferably 2.5 ≤ m ≤ 4.0, more preferably 2.8 ≤ m ≤ 4.0, and even more preferably 2.8 ≤ m < 4.0.

[0078] n can satisfy 0 < n ≤ 3.0, preferably 0 < n ≤ 0.5, more preferably 0.1 ≤ n ≤ 0.4, and even more preferably 0.1 ≤ n ≤ 0.27.

[0079] The preferred numerical ranges for x, y, x+y, m, and n are as follows.

[0080] 1.3 ≤ x < 2.0

[0081] 0.01≤y≤0.1

[0082] 1.3 ≤ x + y ≤ 2.0

[0083] 2.8 ≤ m < 4.0

[0084] 0.1 ≤ n ≤ 0.27

[0085] Optimization of x, y, x+y, m, and n can sometimes further improve the luminescence properties of α-type silon phosphors. Furthermore, optimization of x, y, x+y, m, and n can sometimes more easily and appropriately control the average linear expansion coefficient α′.

[0086] (Regarding lattice constant and lattice volume)

[0087] The lattice constant α of the α-type silron phosphor in this embodiment at 25°C is... 25 Preferred The above and The following is the lattice constant c 25 Preferred The above and Incidentally, in the crystal structure of α-type silron, the lattice constant b of the unit lattice at 25°C is... 25 Become with a 25 Same value.

[0088] Furthermore, the lattice volume V of the α-type silron phosphor in this embodiment at 25°C is... 25 Preferred The above and the following.

[0089] As described above, it can be inferred that the α-type silane of this embodiment has a crystal structure that readily and efficiently emits fluorescence. The numerical range of these lattice constants is considered to reflect a "crystal structure that readily and efficiently emits fluorescence."

[0090] The above values ​​can be obtained using the Pawley method.

[0091] (Regarding the average linear expansion coefficient at low temperatures and the average linear expansion coefficient at high temperatures)

[0092] In the α-type silon phosphor of this embodiment, the luminescence properties are sometimes further improved because the average linear expansion coefficient at low temperature or at high temperature is within an appropriate range.

[0093] Specifically, when the average linear expansion coefficient of the α-type silon phosphor in this embodiment is set as α1′ at 25 to 300°C, and the average linear expansion coefficient at 700 to 900°C is set as α2′, the ratio of α2′ / α1′ is preferably 1.3 to 1.8, more preferably 1.3 to 1.7, and even more preferably 1.3 to 1.6.

[0094] The following section provides a detailed explanation of the methods for determining α1′ and α2′.

[0095] • Method for determining the average linear expansion coefficient α1′ at 25–300℃

[0096] (1) The lattice constant a obtained by the Pawley method 25 c 25 Substituting the values ​​of (the definitions of these symbols are the same as above) into the following formula, calculate the lattice volume V at 25°C. 25 Incidentally, the crystal structure of α-type silron is hexagonal, therefore the lattice volume is expressed by this formula.

[0097] [Number 3]

[0098]

[0099] (2) Similarly, the lattice constant a at 300℃ is used. 300 c 300 The value of V is used to calculate the lattice volume V at 300℃. 300 .

[0100] (3) Calculate the volume expansion coefficient β1 according to the following formula. ΔT is 300℃-25℃=275℃.

[0101] [Number 4]

[0102] V 300 =V 25 ·(1+β1ΔT)

[0103]

[0104] (4) Assuming the sample is an isotropic material, the average linear expansion coefficient α1′ of the polycrystalline material is calculated using the formula α1′=β1 / 3.

[0105] • Method for determining the average linear expansion coefficient α2′ at 700–900℃

[0106] (1) The lattice constant a at 700℃ was determined by the Pawley method. 700 c 700 The value of V is then substituted into the following formula to calculate the lattice volume V at 700℃. 700 .

[0107] Incidentally, the crystal structure of α-type cyrones is hexagonal, therefore the lattice volume is represented by this formula.

[0108] [Number 5]

[0109]

[0110] (2) Similarly, determine the lattice constant a at 900℃. 900 c 900 The value of is then calculated. Then, the lattice volume V at 900℃ is calculated. 900 .

[0111] (3) Calculate the volume expansion coefficient β2 using the following formula. ΔT is 900℃-700℃=200℃.

[0112] [Number 6]

[0113] V 900 =V 700 ·(1+β2ΔT)

[0114]

[0115] (4) Assuming the sample is an isotropic material, the average linear expansion coefficient α2′ of the polycrystalline material is calculated using the formula α2′=β2 / 3.

[0116] (Regarding traits)

[0117] The α-type silon phosphor in this embodiment is typically in powder form.

[0118] The lower limit of the median particle size D50 of the powdered α-type silon phosphor particles is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. Furthermore, the upper limit of the median particle size D50 is preferably 30 μm or less, more preferably 20 μm or less. That is, the median particle size D50 is preferably 1 to 30 μm, more preferably 5 to 30 μm, and even more preferably 10 to 20 μm. By setting the median particle size D50 to 5 μm or more, the transparency of the composite described later can be further improved. On the other hand, by setting the median particle size D50 to 30 μm or less, the generation of debris can be suppressed when the composite is cut and processed using a cutting machine or the like.

[0119] The median particle size D50 can be determined by laser diffraction scattering according to JIS R1629:1997. For more specific determination methods, refer to the examples described later.

[0120] <Preparation method of α-type silon phosphor>

[0121] As described above, the α-type silon phosphor of this embodiment can be manufactured not only by using appropriate amounts of appropriate raw materials, but also by employing appropriate manufacturing conditions. Hereinafter, an example of the manufacturing method will be described.

[0122] Mixing of raw materials

[0123] First, raw materials containing elements constituting Eu-containing α-type silon phosphor particles are mixed. As a calcium raw material, calcium is in a high concentration of solid solution in α-type silon phosphor particles with low oxygen content synthesized using calcium nitride. Especially with a high Ca solid solution concentration, phosphors with emission peak wavelengths at higher wavelengths (above 590 nm, more specifically, above 590 nm and below 610 nm, and even more specifically, above 592 nm and below 608 nm) can be obtained compared to conventional compositions using oxide raw materials.

[0124] Other than those mentioned above, examples of raw material powders include silicon nitride, aluminum nitride, and Eu compounds. Eu compounds include europium oxide, compounds that become europium oxide upon heating, and europium nitride. Europium nitride, which can reduce the oxygen content in the system, is preferred.

[0125] Alternatively, pre-synthesized α-type silon phosphor particles can be added to an appropriate amount of raw material powder. These phosphor particles serve as the basis for grain growth, sometimes resulting in α-type silon phosphor particles with relatively large short-axis diameters. Furthermore, the grain shape can sometimes be controlled by changing the morphology of the added α-type silon particles.

[0126] Methods for mixing raw materials include dry mixing and wet mixing in an inert solvent that does not substantially react with the components of the raw materials, followed by solvent removal. Mixing apparatus includes V-type mixers, rocking mixers, ball mills, and vibratory mills. Regarding the mixing of calcium nitride, which is unstable in the atmosphere, since its hydrolysis or oxidation can affect the properties of the synthesized product, it is preferable to carry out the mixing in a glove box, an inert environment.

[0127] • Heat treatment (firing)

[0128] The resulting powder (hereinafter referred to as the raw material powder) is filled into a container made of a material with low reactivity to the raw material and the synthesized phosphor, such as a boron nitride container. Then, it is heated in a nitrogen atmosphere for a specified time. This yields an α-type silon phosphor. The heat treatment temperature is preferably set to 1650°C or higher and 1950°C or lower.

[0129] By setting the heat treatment temperature above 1650°C, the amount of unreacted product residue can be suppressed, and primary particles can be fully grown. Furthermore, by setting the heat treatment temperature below 1950°C, significant interparticle sintering can be suppressed.

[0130] From the viewpoint of suppressing interparticle sintering during heating, it is preferable to pack the raw material powder into the container in a loose manner. Specifically, when filling the raw material powder into the container, it is preferable to set the bulk density to 0.6 g / cm³. 3 the following.

[0131] Regarding the heating time in the heat treatment, the preferred time range is 2 hours or more but less than 24 hours, which is a time range that will not result in excessive unreacted material, insufficient primary particle growth, or sintering between particles.

[0132] The above-described process generates ingot-shaped α-type silon phosphors. For these ingot-shaped α-type silon phosphors, by using pulverizing processes with crushers, mortars, ball mills, vibratory mills, jet mills, etc., and subsequent sieving processes, powdered α-type silon phosphors with adjusted secondary particle sizes can be obtained. Furthermore, by removing small, non-precipitating secondary particles dispersed in the aqueous solution, the particle size of the secondary particles can be adjusted.

[0133] Annealing process

[0134] In this embodiment, it is preferable to perform a heating (annealing) treatment on the powdered α-type silane phosphor obtained by heat treatment in a nitrogen atmosphere. In this specification, this heating treatment in a nitrogen atmosphere is referred to as the "annealing process." The heating temperature in the annealing process is preferably 1300–1600°C, more preferably 1400–1500°C. If the heating temperature is above 1600°C, decomposition of the α-type silane and volatilization of the luminescent centers (Eu) may sometimes occur, which is therefore undesirable. Furthermore, if the heating temperature is below 1300°C, crystallinity may not be sufficiently improved, which is also undesirable.

[0135] The heating temperature of the annealing process is preferably lower than the heating temperature of the aforementioned heating process (firing).

[0136] The pressure for the annealing process is preferably set at or near atmospheric pressure, specifically 0.02 to 0.9 MPa (gauge pressure).

[0137] The annealing process is preferably 5 to 20 hours, more preferably 10 to 18 hours.

[0138] • Hydrogen annealing process

[0139] Following the annealing process, the processed material obtained in the annealing process is subjected to heat treatment in a hydrogen atmosphere. In this specification, this process is referred to as the "hydrogen annealing process".

[0140] In the hydrogen annealing process, it is preferable to cool the α-type silon phosphor after the above annealing process to approximately room temperature, and then perform heat treatment in a hydrogen atmosphere. By continuously performing the annealing process and the hydrogen annealing process, the fluorescence properties are significantly improved.

[0141] According to the inventors, the hydrogen annealing process is a treatment used to reduce defective portions in the phosphor. It is believed that through heat treatment in a hydrogen environment, hydrogen enters the crystal and stabilizes the crystal's defects. As a result, it is believed that an α-type silon phosphor with an average linear expansion coefficient α′ of 4.2 ppm / ℃ or higher and 4.6 ppm / ℃ or lower, and good luminescence properties can be obtained.

[0142] The heating temperature in the hydrogen annealing process is preferably 1300–1600°C, more preferably 1400–1500°C. If the heating temperature is below 1300°C, hydrogen will not enter the crystal lattice, making it difficult to achieve the desired effect; if the temperature is above 1600°C, the crystal structure of the α-type silron phosphor may decompose. Furthermore, the heating temperature in the hydrogen annealing process is preferably set to a temperature lower than that in the firing process.

[0143] The pressure in the hydrogen annealing process is preferably set at or near atmospheric pressure, specifically 0.02 to 0.9 MPa (gauge pressure).

[0144] The hydrogen annealing process is preferably 3 to 16 hours, more preferably 5 to 12 hours.

[0145] The hydrogen used in the hydrogen annealing process preferably has a purity of 99% or higher. Hydrogen with a purity of 99.9% or higher is particularly preferred.

[0146] However, as long as the α-type silon phosphor of this embodiment is available, a mixture of hydrogen and other gases can be used in the hydrogen annealing process. Examples of other gases include rare gases such as nitrogen and argon. Preferably, the mixture contains 30 vol% or more of hydrogen, more preferably 40 vol% or more of hydrogen.

[0147] Acid treatment process

[0148] In this embodiment, acid treatment is preferably performed after the above-described steps. This can sometimes reduce heterogeneous phases that do not contribute to luminescence or cause a decrease in luminescence properties, thereby further improving luminescence properties.

[0149] In the acid treatment process, for example, an α-type silon phosphor is immersed in an acidic aqueous solution. Examples of acidic aqueous solutions include an acidic aqueous solution containing one acid selected from hydrofluoric acid, nitric acid, hydrochloric acid, etc., or a mixed acid aqueous solution obtained by mixing two or more of the aforementioned acids. More preferably, it is an aqueous solution of hydrofluoric acid containing only hydrofluoric acid and a mixed acid aqueous solution obtained by mixing hydrofluoric acid and nitric acid. The concentration of the original acidic aqueous solution can be appropriately set according to the strength of the acid used, for example, preferably 0.7% or more and 100% or less, more preferably 0.7% or more and 40% or less. Furthermore, the temperature during acid treatment is preferably 60°C or more and 90°C or less, and the reaction time (immersion time) is preferably 15 minutes or more and 80 minutes or less.

[0150] High-speed stirring facilitates thorough acid treatment of the phosphor surface. "High-speed" here depends on the stirring apparatus used, but when using a laboratory-grade magnetic stirrer, the stirring speed is, for example, 400 rpm or higher, practically 400 rpm or higher but less than 500 rpm. For the general purpose of stirring to continuously supply fresh acid to the particle surface, a stirring speed of around 200 rpm is sufficient. However, by performing high-speed stirring at 400 rpm or higher, a physical action is added in addition to the chemical action, thus facilitating thorough particle surface treatment.

[0151] <Light-emitting device>

[0152] Figure 1 This is a schematic cross-sectional view illustrating the structure of a light-emitting device.

[0153] like Figure 1As shown, the light-emitting device 100 includes a light-emitting element 120, a heat sink 130, a housing 140, a first lead frame 150, a second lead frame 160, a bonding wire 170, a bonding wire 172, and a composite 40.

[0154] The light-emitting element 120 is mounted on a designated area on the upper surface of the heat sink 130. By mounting the light-emitting element 120 on the heat sink 130, the heat dissipation of the light-emitting element 120 can be improved. Alternatively, a packaging substrate can be used instead of the heat sink 130.

[0155] The light-emitting element 120 is a semiconductor element that emits excitation light. For example, an LED chip that generates light with a wavelength of 300 nm or more and 500 nm or less, corresponding to near-ultraviolet to blue light, can be used as the light-emitting element 120. An electrode (not shown) disposed on the upper surface of the light-emitting element 120 is connected to the surface of the first lead frame 150 via a bonding wire 170 such as a gold wire. Furthermore, another electrode (not shown) formed on the upper surface of the light-emitting element 120 is connected to the surface of the second lead frame 160 via a bonding wire 172 such as a gold wire.

[0156] A roughly funnel-shaped recess with an aperture that gradually widens from the bottom surface upwards is formed in the housing 140. A light-emitting element 120 is disposed on the bottom surface of the recess. The wall of the recess surrounding the light-emitting element 120 functions as a reflector.

[0157] The composite 40 fills the aforementioned recess in which the housing 140 forms a wall. The composite 40 is a wavelength conversion component that lengthens the wavelength of the excitation light emitted from the light-emitting element 120. As the composite 40, the phosphor 1 of this embodiment is dispersed in the sealing material 30 such as resin. The light-emitting device 100 emits a mixed color of light from the light-emitting element 120 and light generated from the phosphor particles 1 that absorb and excite the light from the light-emitting element 120. Preferably, the light-emitting device 100 emits white light through the mixing of the light from the light-emitting element 120 and the light generated from the phosphor 1.

[0158] Incidentally, examples of resins that can be used as sealing materials 30 in composite 40 include transparent resins such as silicone resin, epoxy resin, and polyurethane resin. Composite 40 can be manufactured, for example, by adding the α-type silron phosphor of this embodiment to a liquid resin or powdered glass or ceramic and mixing it uniformly, and then curing or sintering it by heat treatment.

[0159] The light-emitting device 100 of this embodiment has good light-emitting characteristics by using the above-described α-type silron phosphor as phosphor 1.

[0160] Incidentally, in Figure 1The example shown is a surface-mount type light-emitting device, but the light-emitting device is not limited to surface-mount type, and can also be bullet type, COB (chip-on-board) type, CSP (chip-scale package) type.

[0161] The embodiments of the present invention have been described above, but these are merely examples, and various other structures can also be employed. Furthermore, the present invention is not limited to the above embodiments, and modifications and alterations within the scope of achieving the objectives of the present invention are included in the present invention.

[0162] Example

[0163] The embodiments of the present invention will be described in detail based on examples and comparative examples. It should be noted, however, that the present invention is not limited to these examples.

[0164] <Example 1: Fabrication of α-type silon phosphor>

[0165] Inside a glove box, to achieve a m value of 3.75, an n value of 0, an x ​​value of 1.795, and a y value of 0.08, the following raw material powders were dry-mixed: 60.14 wt% Si3N4 powder (manufactured by Ube Industries, Ltd., E10 grade), 23.96 wt% AlN powder (manufactured by Tokuyama Corporation, E grade), 2.07 wt% EuN powder (manufactured by Kojundo Chemical Lab. Co., Ltd.), and 13.83 wt% Ca3N2 powder (manufactured by Kojundo Chemical Lab. Co., Ltd.). The mixture was then passed through a nylon sieve with a mesh size of 250 μm. This yielded the raw material powder mixture.

[0166] 120g of the raw material powder was filled into a covered cylindrical boron nitride container (manufactured by DENKA COMPANY LIMITED, N-1 grade) with an internal volume of 0.4 liters.

[0167] Using an electric furnace equipped with a carbon heater, the container filled with the raw material mixture powder was heated at 1800°C for 16 hours under atmospheric pressure and nitrogen atmosphere. Since the calcium nitride contained in the raw material mixture powder is easily hydrolyzed in air, the boron nitride container filled with the raw material mixture powder was quickly placed into the electric furnace after being removed from the glove box, and immediately subjected to vacuum degassing to prevent the calcium nitride from reacting.

[0168] The synthesized material was gently crushed using a mortar and pestle, allowing it to pass entirely through a 150 μm mesh sieve to obtain phosphor powder. The crystal phase of this phosphor powder was investigated using CuKα-ray powder X-ray diffraction (hereinafter referred to as XRD). The observed crystal phase was α-type silon.

[0169] Using an electric furnace equipped with a carbon heater, a boron nitride container filled with the obtained phosphor powder was heated at 1400°C for 16 hours (annealing process) under atmospheric pressure and nitrogen atmosphere. The synthesized material was then gently crushed in a mortar and pestle until it passed entirely through a sieve with a mesh size of 150 μm, yielding the phosphor powder.

[0170] Subsequently, using an electric furnace equipped with a metal heater, the boron nitride container filled with the aforementioned phosphor powder was heated at 1400°C for 16 hours in an atmospheric pressure hydrogen atmosphere (hydrogen annealing process). The synthesized material was then gently crushed in a mortar and pestle, allowing it to pass entirely through a 150μm mesh sieve to obtain the phosphor powder.

[0171] Next, 50 ml of 50% hydrofluoric acid and 50 ml of 70% nitric acid were mixed to prepare a stock solution. 300 ml of distilled water was added to the stock solution to dilute its concentration to 25%, preparing 400 ml of a mixed acid aqueous solution. 30 g of powder composed of the aforementioned α-type silon phosphor particles was added to this mixed acid aqueous solution. The temperature of the mixed acid aqueous solution was maintained at 80°C, and acid treatment was performed for 60 minutes while stirring with a magnetic stirrer at 450 rpm. After acid treatment, the powder was thoroughly rinsed with distilled water, filtered, dried, and then passed through a 45 μm mesh sieve.

[0172] Through the above methods, powdered α-type silon phosphors were obtained.

[0173] Compositional analysis was performed on the obtained α-type silon phosphors, and x, y, x+y, m, and n in the general formula were determined. The specific method of compositional analysis is as follows.

[0174] The content of Eu, Ca, Si and Al in the phosphor was quantitatively analyzed using an ICP emission spectrometer (SPECTRO Corporation, CIROS-120) after the α-type silon phosphor was dissolved by pressurized acid decomposition.

[0175] Furthermore, the O and N content in the fluorophore was quantitatively analyzed using an oxygen and nitrogen analyzer (manufactured by Horiba, Ltd., EMGA-920).

[0176] The compositional analysis results were converted into the general formula (Ca) of α-type silon with (Si+Al) / 12=1 as the basic unit. x Eu y (Si) 12-(m+n) Al m+n (O) n N 16-n The results are: m: 3.5, n: 0.27, x: 1.63, y: 0.05, x+y: 1.68.

[0177] <Calculation of lattice constant and average linear expansion coefficient>

[0178] (X-ray diffraction measurement)

[0179] An α-type silon phosphor was placed on a sample plate with the sample surface aligned with the sample plate surface, and the sample was stretched by a glass plate. X-ray diffraction measurements were then performed under the following conditions. Measurements were also performed on Si (NIST SRM 640c, hereinafter also referred to as "Si_640c"), which served as an angular standard sample (external standard).

[0180] The Ultima IV X-ray diffraction apparatus manufactured by Rigaku Corporation uses a parallel beam method optical system.

[0181] X-ray source Cu sealed tube

[0182] Apply voltage / current 40kV / 40mA

[0183] Detector blink counter

[0184] High-temperature device for test specimens

[0185] Measure the atmospheric N2 flow rate (30 mL / min).

[0186] Set temperatures: 25℃, 300℃, 500℃, 700℃, 900℃ (excluding Si_640c)

[0187] 25℃ (Si_640c)

[0188] Heating rate: 20℃ / minute

[0189] 10-minute interval

[0190] The measurement angle range is 2θ = 24 to 140°.

[0191] Sampling width 0.04°

[0192] Scanning speed 2° / minute

[0193] The measurement was repeated 4 times (excluding Si_640c).

[0194] 3 times (Si_640c)

[0195] Slit structure: Incident side Soler slit: 5.0°; Receiving side Soler slit: 5.0°

[0196] Thin Film PSA

[0197] DS: 1mm, DS longitudinal: 10mm, SS: open, RS: open

[0198] Pt sample plate

[0199] (Calculation of lattice constant)

[0200] In the above X-ray diffraction measurements, the results obtained at various temperatures (25℃, 300℃, 500℃, 700℃, and 900℃) were analyzed using Jade 9, a powder X-ray diffraction pattern analysis software manufactured by Materials Data Corporation. The precise lattice constant was then calculated. The conditions related to the analysis are described below.

[0201] Method: Pawley Method

[0202] Analysis temperatures: 25℃, 300℃, 500℃, 700℃, 900℃

[0203] The angular range is 2θ = 24–140° (Note 1).

[0204] Background 4th-Order Polynomial Precision

[0205] Peak shift zero-point correction 2θ 0.005948 (Note 2)

[0206] Sample displacement cosθ0 (fixed)

[0207] Vertical divergence cot(2θ)-0.012557 (Note 2)

[0208] Peak shape pseudo-voigt function

[0209] Peak intensity ratio precision

[0210] (Note 1: In the Pawley method analysis based on the angle range of 2θ = 24 to 140°, when diffraction lines other than α-type silrons appeared, these diffraction lines were appropriately excluded from the analysis.)

[0211] (Note 2: The results of the analysis of the standard sample (Si_640c) are used, and the obtained values ​​are employed.)

[0212] (Calculation of the coefficient of volume expansion)

[0213] (1) The lattice constant a was plotted relative to the measurement temperature T. T and c T The graph was then used. The approximate linear equation for the temperature range of 25–900 °C was then determined. This approximate linear equation can be obtained using the least squares method. Incidentally, in the crystal structure of α-type silon, α... T and b T To become the same value.

[0214] (2) Using an approximate linear formula, the lattice constant a at 25℃ was calculated. 25 and c 25 .

[0215] (3) Using an approximate linear formula, the lattice constant a at 900℃ is calculated. 900 and c 900 .

[0216] (4) Using the lattice constant a 25 and c 25 The value was used to calculate the lattice volume V at 25℃. 25 (Note 3)

[0217] (5) Using the lattice constant a 900 and c 900 The value was used to calculate the lattice volume V at 900℃. 900 (Note 3)

[0218] (6) Calculate the volume expansion coefficient β using the following formula. Here, ΔT is 900℃-25℃=875℃.

[0219] (Note 3: The crystal structure of α-type cyrones is hexagonal.)

[0220] [Number 7]

[0221] V 900 =V 25 ·(1+βΔT)

[0222]

[0223] (Calculation of the mean linear expansion coefficient)

[0224] The average linear expansion coefficient α′ is calculated using the formula α′=β / 3. Incidentally, this formula α′=β / 3 is used to calculate the average linear expansion coefficient as a polycrystalline material, assuming the sample is isotropic.

[0225] (Calculation of the average linear expansion coefficient α1′ at 25–300℃ and the average linear expansion coefficient α2′ at 700–900℃)

[0226] Through the above series of steps, the average linear expansion coefficient α1′ at 25–300℃ and the average linear expansion coefficient α2′ at 700–900℃ are calculated.

[0227] (Determination of particle size distribution and calculation of median particle size)

[0228] The determination was performed using a Microtrac MT3300EXII (manufactured by Microtrac BEL Corp.) and by laser diffraction scattering in accordance with JISR 1629:1997.

[0229] Specifically, firstly, 0.5 g of powdered α-type silane phosphor was added to 100 cc of deionized water and dispersed for 3 minutes using an Ultrasonic Homogenizer US-150E (NIHONSEIKI KAISHALTD., chip size φ20 mm, amplitude 100%, oscillation frequency 19.5 kHz, amplitude approximately 31 μm) to obtain a dispersion. This dispersion was then placed in an MT3300EXII reactor, and the particle size distribution was measured. The median particle size D50 was determined based on the obtained particle size distribution.

[0230] <Evaluation of Luminescent Properties>

[0231] The obtained powdered α-type silon phosphor was analyzed by measuring its absorbance, internal quantum efficiency, and external quantum efficiency using a spectrophotometer (MCPD-7000 manufactured by Otsuka Electronics Co., Ltd.), and the results were calculated using the following steps.

[0232] Powdered α-type silron phosphor was filled in a manner that smoothed the surface of the concave groove. The groove was then installed at a predetermined position on the integrating sphere. Monochromatic light of 455 nm wavelength, split from a light source (Xe lamp), was guided into the integrating sphere using an optical fiber. This monochromatic light was then applied to the phosphor sample, and the fluorescence spectrum of the sample was measured.

[0233] A standard reflector with a reflectivity of 99% (Spectralon manufactured by Labsphere) was installed on the sample section, and the spectrum of the excitation light at a wavelength of 455 nm was measured. At this time, the number of excitation photons (Qex) was calculated based on the spectrum in the wavelength range above 450 nm and below 465 nm.

[0234] A groove filled with powdered α-type silon phosphor was installed in the sample section, and the number of excitation-reflected photons (Qref) and the number of fluorescence photons (Qem) were calculated based on the obtained spectral data. The number of excitation-reflected photons was calculated within the same wavelength range as the number of excitation photons, and the number of fluorescence photons was calculated within the range of 465 nm to 800 nm.

[0235] Absorption rate (%) = (Qex - Qref) / Qex × 100

[0236] Internal quantum efficiency (%) = (Qem / (Qex-Qref)) × 100

[0237] External quantum efficiency (%) = (Qem / Qex) × 100

[0238] When the above-described measurement method was used to measure the standard sample NSG1301 sold by Sialon Co., Ltd., the external quantum efficiency was 55.6% and the internal quantum efficiency was 74.8%. The apparatus was calibrated using this sample as a standard.

[0239] <Example 2: Fabrication and Evaluation of α-type silon phosphors>

[0240] The feed composition was changed, but the α-type silon phosphor was manufactured using the same method as in Example 1. Then, the luminescence properties were evaluated.

[0241] In the fabricated α-type silon phosphor, the values ​​are: m: 3.0, n: 0.25, x: 1.45, y: 0.05, and x+y: 1.50.

[0242] <Example 3: Fabrication and Evaluation of α-type silon phosphors>

[0243] The feed composition was changed, but the α-type silon phosphor was manufactured using the same method as in Example 1. Then, the luminescence properties were evaluated.

[0244] In the fabricated α-type silon phosphor, the values ​​are: m: 4.0, n: 0.21, x: 1.94, y: 0.06, and x+y: 2.01.

[0245] <Comparative Example 1: Fabrication and Evaluation of α-type silon phosphors>

[0246] The feed composition was changed, and the hydrogen annealing process was omitted. Alpha-type silon phosphors were manufactured using the same method as in Example 1. Then, the luminescence properties were evaluated.

[0247] In the fabricated α-type silon phosphor, the values ​​are: m: 2.0, n: 0.32, x: 0.94, y: 0.06, and x+y: 1.00.

[0248] <Comparative Example 2: Fabrication and Evaluation of α-type silon phosphors>

[0249] The feed composition was changed, and the hydrogen annealing process was omitted. Alpha-type silon phosphors were manufactured using the same method as in Example 1. Then, the luminescence properties were evaluated.

[0250] In the α-type silon phosphor produced, the m value is 3.5, the n value is 1.47, the x value is 1.70, the y value is 0.05, and the x+y value is 1.75.

[0251] Information related to each embodiment and comparative example is summarized in the table below.

[0252] The units for each value in the table are as follows.

[0253] α′, α1′ and α2′: ppm / ℃

[0254] a 25 and c 25 :

[0255] V 25 :

[0256] Absorption rate, internal quantum efficiency, and external quantum efficiency: %

[0257] [Table 1]

[0258] Table 1

[0259] m n x y x+y Annealing process Example 1 3.5 0.27 1.63 0.05 1.68 Annealing process + hydrogen annealing process Example 2 3.0 0.25 1.45 0.05 1.50 Annealing process + hydrogen annealing process Example 3 4.0 0.21 1.94 0.06 2.01 Annealing process + hydrogen annealing process Comparative Example 1 2.0 0.32 0.94 0.06 1.00 Annealing process only Comparative Example 2 3.5 1.47 1.70 0.05 1.75 Annealing process only

[0260] [Table 2]

[0261]

[0262] As shown in Tables 1 and 2, it has the general formula: (Ca x Eu y (Si) 12-(m+n) Al m+n (O) n N 16-n Alpha-type silon phosphors that satisfy the following conditions (0 < x < 2.0, 0 < y ≤ 0.5, 0.3 ≤ x + y ≤ 2.2, 0 < m ≤ 4.0, and 0 < n ≤ 3.0) and have an average linear expansion coefficient α′ of 4.2 ppm / ℃ or higher and 4.6 ppm / ℃ or lower at 25–900 °C exhibit better internal and external quantum efficiencies than alpha-type silon phosphors that do not meet these conditions.

[0263] This application claims priority based on Japanese Patent Application No. 2023-059122, filed on March 31, 2023, the disclosure of which is incorporated herein in its entirety.

[0264] Symbol Explanation

[0265] 1. Fluorescent

[0266] 30 Sealing material

[0267] 40 complex

[0268] 100 Light-emitting devices

[0269] 120 Light-emitting element

[0270] 130 heatsink

[0271] 140 housing

[0272] 150 First lead frame

[0273] 160 Second lead frame

[0274] 170 joint line

[0275] 172 Joint line

Claims

1. An α-type silon phosphor, represented by the following general formula, having an average linear expansion coefficient α´ of 4.2 ppm / ℃ or higher and 4.6 ppm / ℃ or lower at 25–900 °C. General formula: (Ca x , Eu y )(Si 12-（m+n） Al m+n )(O n N 16-n ), In the general formula, x, y, m, and n satisfy the following: 1.3≤x＜2.0； 0.01≤y≤0.06； 1.3 ≤ x + y ≤ 2.0; 2.8≤m＜4.0； 0.1≤n≤0.27。 2. The α-type silon phosphor according to claim 1, wherein, When the average linear expansion coefficient at 25–300℃ is set as α1´, and the average linear expansion coefficient at 700–900℃ is set as α2´, α2´ / α1´ is 1.3–1.

8.

3. The α-type silon phosphor according to claim 1 or 2, wherein, At 25°C, the lattice constant a of a unit crystal lattice 25 For atoms with a lattice constant c between 7.900 Å and 7.960 Å, the lattice constant is... 25 It is above 5.720 Å and below 5.780 Å.

4. The α-type silon phosphor according to claim 1 or 2, wherein, At 25°C, the lattice volume V of a unit crystal lattice 25 308 Å 3 Above and 320Å 3 the following.

5. A light-emitting device, comprising: Light-emitting elements; and The wavelength conversion section includes the α-type silon phosphor as described in claim 1 or 2, and converts the light emitted from the light-emitting element to a longer wavelength.

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