Aluminate phosphor, light emitting device, and method for manufacturing aluminate phosphor

Abstract

This invention provides an aluminate phosphor with high luminescence intensity, a light-emitting device, and a method for manufacturing the aluminate phosphor. The aluminate phosphor has a composition comprising a first element and a second element, wherein the first element contains one or more elements selected from Ba and Sr, and the second element contains Mg and Mn. In the composition of the aluminate phosphor, when the molar ratio of Al is set to 10, the total molar ratio of the first element is variable a, the total molar ratio of the second element is variable b, the molar ratio of Sr is the product of variable m and variable a, and the molar ratio of Mn is the product of variable n and variable b. Variables a and b satisfy the following conditions (1), variable m satisfies the following condition (2), and variable n satisfies the following condition (3): 0.5 < b < a ≤ 0.5b + 0.5 < 1.0 (1), 0 ≤ m ≤ 1.0 (2), 0.4 ≤ n ≤ 0.7 (3).

Description

[0001] This application is a divisional application of Chinese invention application No. 201710417145.5, filed on June 6, 2017, entitled "Aluminate phosphor, light-emitting device and method for manufacturing aluminate phosphor". Technical Field

[0002] This invention relates to aluminate phosphors, light-emitting devices, and methods for manufacturing aluminate phosphors. Background Technology

[0003] Various light-emitting devices have been developed that combine light-emitting diodes (LEDs) with phosphors to emit white, bulb-colored, orange, and other light. In these devices, the desired emitted color is obtained through the principle of light mixing. Light-emitting devices emitting white light, using light-emitting elements that emit blue light and phosphors that emit yellow light, are known. Light-emitting devices using light-emitting elements that emit blue light and phosphors that emit yellow light, etc., are typically required for use in a wide range of fields, including lighting, automotive lighting, displays, and LCD backlights. Specifically, phosphors used in light-emitting devices for LCD backlights require excellent luminous efficiency and color purity to reproduce a wide range of colors on the chromaticity coordinate system. In particular, phosphors used in light-emitting devices for LCD backlights require a narrow full width at half maximum (FWHM) and high color purity, from the perspective of expanding the range of color reproducibility.

[0004] For example, green phosphors with a narrow half-width at half-maximum (WHM) of emission peaks in their emission spectra are known to be (Ba,Sr)MgAl 10 O 17 Mn 2＋ Manganese-activated aluminate phosphors (for example, see Patent Document 1). The manganese-activated aluminate phosphor disclosed in Patent Document 1 is a phosphor that emits light when excited by vacuum ultraviolet light with a wavelength of about 10 nm to 190 nm, specifically, it is a phosphor that emits light when excited by vacuum ultraviolet light of 146 nm.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2004-155907 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] However, when the manganese-activated aluminate phosphor disclosed in Patent Document 1 is combined with a light-emitting element that emits light with a peak emission wavelength in the range of 380 nm to 485 nm (hereinafter, sometimes referred to as the "near-ultraviolet to blue region"), the luminous intensity is insufficient.

[0010] Therefore, the objective of one embodiment of the present invention is to provide an aluminate phosphor, a light-emitting device, and a method for manufacturing an aluminate phosphor that exhibits high luminescence intensity through photoexcitation in the near-ultraviolet to blue region.

[0011] Solution for solving the problem

[0012] The solutions to the aforementioned problem include the following approaches.

[0013] The first aspect of the present invention provides an aluminate phosphor having a composition comprising a first element and a second element, wherein the first element contains one or more elements selected from Ba and Sr, and the second element contains Mg and Mn. In the composition of the aluminate phosphor, when the molar ratio of Al is set to 10, the total molar ratio of the first element is variable a, the total molar ratio of the second element is variable b, the molar ratio of Sr is the product of variable m and variable a, the molar ratio of Mn is the product of variable n and variable b, wherein variables a and b satisfy the following condition (1), and variable m satisfies the following condition (2), and variable n satisfies the following condition (3).

[0014] 0.5<b<a≤0.5b+0.5<1.0 (1)

[0015] 0≤m≤1.0 (2)

[0016] 0.4≤n≤0.7 (3)

[0017] A second aspect of the present invention provides a light-emitting device comprising the aluminate phosphor and an excitation light source.

[0018] The third aspect of the present invention provides a method for manufacturing an aluminate phosphor, the aluminate phosphor having a composition comprising a first element, a second element, Al and O, the first element comprising one or more elements selected from Ba and Sr, the second element comprising Mg and Mn, the method comprising the following steps: mixing a compound containing each element and heat-treating it such that when the molar ratio of Al in the composition is set to 10, the total molar ratio of the first element (Ba, Sr) is set as variable a, the total molar ratio of the second element (Mg and Mn) is set as variable b, the molar ratio of Sr is set as the product of variable m and variable a, and the molar ratio of Mn is set as the product of variable n and variable b, the variables a and b are numbers that satisfy the following condition (1), the variable m satisfies the following condition (2), and the variable n satisfies the following condition (3).

[0019] 0.5<b<a≤0.5b+0.5<1.0 (1)

[0020] 0≤m≤1.0 (2)

[0021] 0.4≤n≤0.7 (3)

[0022] The effects of the invention

[0023] According to one embodiment of the present invention, an aluminate phosphor, a light-emitting device, and a method for manufacturing an aluminate phosphor can be provided, which have high luminescence intensity by excitation with light having an emission spectrum in the range of 380 nm to 485 nm. Attached Figure Description

[0024] Figure 1 This is a schematic cross-sectional view showing an example of a light-emitting device;

[0025] Figure 2 The emission spectra of the aluminate phosphors of Example 1 and Comparative Example 1 are shown.

[0026] Figure 3 The reflectance spectra of the aluminate phosphors of Example 1 and Comparative Example 1 are shown.

[0027] Symbol Explanation

[0028] 10: Light-emitting element, 40: Molded body, 50: Fluorescent component, 71: First phosphor, 72: Second phosphor, 100: Light-emitting device. Detailed Implementation

[0029] The aluminate phosphor, light-emitting device, and method for manufacturing the aluminate phosphor of the present invention will be described below based on embodiments. However, the embodiments shown below are examples used to embody the technical concept of the present invention, and the present invention is not limited to the aluminate phosphor, light-emitting device, and method for manufacturing the aluminate phosphor described below. Furthermore, the relationship between color name and chromaticity coordinates, the relationship between the wavelength range of light and the color name of monochromatic light, etc., follow JIS Z8110.

[0030] Aluminate phosphors

[0031] The aluminate phosphor of the first embodiment of the present invention has a composition comprising a first element and a second element, wherein the first element contains one or more elements selected from Ba and Sr, and the second element contains Mg and Mn. In the composition of the aluminate phosphor, when the molar ratio of Al is set to 10, the total molar ratio of the first element is variable a, the total molar ratio of the second element is variable b, the molar ratio of Sr is the product of variable m and variable a, and the molar ratio of Mn is the product of variable n and variable b. Variables a and b are numbers that satisfy the following condition (1), variable m is a number that satisfies the following condition (2), and variable n is a number that satisfies the following condition (3).

[0032] 0.5<b<a≤0.5b+0.5<1.0 (1)

[0033] 0≤m≤1.0 (2)

[0034] 0.4≤n≤0.7 (3)

[0035] In the composition of the aluminate fluorophore described above, variable a is the total molar ratio of Ba and Sr. In the composition of the aluminate fluorophore described above, if variable a is not a number satisfying condition (1), the crystal structure may be unstable, and the luminescence intensity may decrease. Additionally, in the composition of the aluminate fluorophore described above, variable b is the total molar ratio of Mg and Mn. In the composition of the aluminate fluorophore described above, if variable b is 0.5 or less, the crystal structure may be unstable, and the luminescence intensity may decrease.

[0036] In the composition of the above aluminate phosphor, it is preferred that variables a and b are numbers that satisfy the following condition (4).

[0037] 0.7<b<a≤0.5b+0.5<1.0 (4)

[0038] In the above composition of aluminate phosphors, by making the variable b a number greater than 0.7, the crystal structure of the aluminate phosphor is more stable, which can improve the luminescence intensity of the aluminate phosphor.

[0039] In the composition of the aluminate phosphor described above, the variable m represents the molar ratio of Sr when the total number of moles of Ba and Sr, which are the first elements, is set to 1. The first element can also be all Ba, or it can be all Sr.

[0040] In the composition of the aluminate phosphor described above, the variable n represents the molar ratio of Mn when the total molar number of Mg and Mn, which are the second elements, is set to 1. In the composition of the aluminate phosphor described above, when the variable n, which represents the molar ratio of Mn, is less than 0.4 or greater than 0.7, the luminescence intensity generated by photoexcitation in the near-ultraviolet to blue region sometimes decreases.

[0041] In the composition of the above aluminate phosphor, the variable n is preferably a number that satisfies the condition 0.4≤n≤0.6.

[0042] In the composition of the above aluminate phosphor, the variable n is a number that satisfies the condition 0.4≤n≤0.6. Therefore, the luminescence intensity can be further improved, and the luminescence intensity of aluminate phosphors generated by photoexcitation in the near-ultraviolet to blue region can be further improved.

[0043] In the composition of the above aluminate phosphor, the product (b×n) of the variable n and the variable b representing the molar ratio of Mn is preferably a number that satisfies the condition 0.3 < b×n < 0.6.

[0044] For example, the reason why the luminescence intensity of the manganese-activated aluminate phosphor disclosed in Patent Document 1 is low when excited by light in the near-ultraviolet to blue region is that, as a luminescence characteristic of this phosphor, the absorption rate of light in the near-ultraviolet to blue region is considered to be lower than that of vacuum ultraviolet light. In the aluminate phosphor of the first embodiment of the present invention, when excited by light in the near-ultraviolet to blue region, by increasing the activation amount of Mn beyond the aforementioned specified value, the absorption of light in the near-ultraviolet to blue region increases, thereby improving the luminescence intensity. Furthermore, by reducing the activation amount of Mn beyond the aforementioned specified value, concentration quenching caused by excessive activation can be suppressed. ), and increase luminous intensity.

[0045] The aluminate phosphor described above preferably has a composition represented by formula (I) below. The aluminate phosphor having the composition represented by formula (I) below has high luminescence intensity, which can be further improved by excitation with light in the near-ultraviolet to blue region.

[0046] (Ba 1-m Sr m )a(Mg 1-n Mn n ) b Al 10 O 15＋a＋b (I)

[0047] (In the formula, a, b, m, and n are numbers that satisfy 0.5 < b < a ≤ 0.5b + 0.5 < 1.0, 0 ≤ m ≤ 1.0, and 0.4 ≤ n ≤ 0.7.)

[0048] In the aluminate phosphor of the first embodiment of the present invention, the half-width at half-maximum (WWHM) of the emission peak in the emission spectrum excited by light in the near-ultraviolet to blue region, for example, by light with an emission peak wavelength of 450 nm, is preferably 45 nm or less, more preferably 40 nm or less, and even more preferably 30 nm or less. As a phosphor that emits green light when excited by light in the near-ultraviolet to blue region, a β-Sialon phosphor activated by, for example, europium (Eu) is known. In this β-Sialon phosphor, the WWHM of the emission peak in the emission spectrum irradiated by light with an excitation wavelength of 450 nm is about 50 nm. The aluminate phosphor of the first embodiment of the present invention has a narrower WWHM. In the above-mentioned aluminate phosphor, by making the WWHM of the emission peak in the emission spectrum narrower, the color purity is higher. When a light-emitting device containing the above-mentioned aluminate phosphor is used as, for example, a backlight for liquid crystal, the color reproduction range can be expanded.

[0049] The aluminate phosphor of the first embodiment of the present invention is activated by manganese (Mn) and emits green light upon excitation in the near-ultraviolet to blue region. Specifically, the aluminate phosphor absorbs light in the wavelength range of 380 nm to 485 nm, and the emission peak wavelength in the emission spectrum is preferably in the range of 485 nm to 570 nm, more preferably in the range of 495 nm to 560 nm, and even more preferably in the range of 505 nm to 550 nm.

[0050] Light-emitting device

[0051] Regarding the second embodiment of the present invention, an example of a light-emitting device using the aluminate phosphor of the first embodiment is described based on the accompanying drawings. Figure 1 This is a schematic cross-sectional view showing a light-emitting device 100 according to an embodiment of the present invention.

[0052] The light-emitting device 100 includes a molded body 40, a light-emitting element 10, and a fluorescent component 50. The molded body 40 is integrally formed by a first lead 20, a second lead 30, and a resin portion 42 containing thermoplastic or thermosetting resin. The molded body 40 has recesses with a bottom surface and side surfaces, and the light-emitting element 10 is mounted on the bottom surface of the recesses. The light-emitting element 10 has a pair of positive and negative electrodes, which are electrically connected to the first lead 20 and the second lead 30 respectively via wires 60. The light-emitting element 10 is covered by the fluorescent component 50. The fluorescent component 50 contains, for example, a phosphor 70 that converts the wavelength of light from the light-emitting element 10, and resin. The phosphor 70 further includes a first phosphor 71 and a second phosphor 72. The first lead 20 and the second lead 30, which are connected to the positive and negative electrodes of the light-emitting element 10, face outwards from the outer side of the package constituting the light-emitting device 100, with a portion of the first lead 20 and the second lead 30 exposed. Through these first leads 20 and second leads 30, power can be supplied from the outside to make the light-emitting device 100 emit light.

[0053] The light-emitting element 10 is preferably used as an excitation light source and has a peak emission wavelength in the range of 380 nm to 485 nm. More preferably, the peak emission wavelength range of the light-emitting element 10 is 390 nm to 480 nm, and even more preferably 420 nm to 470 nm. The aluminate phosphor of the first embodiment of the present invention is efficiently excited by an excitation light source having an emission spectrum in the range of 380 nm to 485 nm. In particular, the light from the excitation light source having a peak emission wavelength in the range of 420 nm to 470 nm has a low reflectivity, i.e., a high light absorption rate, and is thus efficiently excited. The aluminate phosphor of the first embodiment of the present invention is efficiently excited by light from an excitation light source having a peak emission wavelength in the aforementioned wavelength range. By using an aluminate phosphor with high luminous intensity, a light-emitting device 100 that emits mixed light from the light-emitting element 10 and the fluorescence from the phosphor 70 can be constructed.

[0054] The half-width of the emission spectrum of the light-emitting element 10 can be set to, for example, below 30 nm.

[0055] The light-emitting element 10 is preferably a semiconductor light-emitting element. By using a semiconductor light-emitting element as the light source, a stable light-emitting device with high efficiency, high linearity of output relative to input, and strong resistance to mechanical shock can be obtained.

[0056] As a semiconductor light-emitting element, for example, a semiconductor using nitride-based semiconductors (In) can be used. X Al Y Ga 1- X-Y A semiconductor light-emitting element (N, 0≤X, 0≤Y, X+Y≤1).

[0057] The light-emitting device 100 preferably contains at least the aluminate phosphor of the first embodiment of the present invention, and contains an aluminate phosphor having a composition represented by formula (I).

[0058] The first phosphor 71, containing the aluminate phosphor of the first embodiment of the present invention, can be incorporated into, for example, the fluorescent component 50 covering the light-emitting element 10 to form a light-emitting device 100. In the light-emitting device 100 where the light-emitting element 10 is covered by the fluorescent component 50 containing the first phosphor 71 (containing the aluminate phosphor), a portion of the light emitted from the light-emitting element 10 is absorbed by the aluminate phosphor and emitted as green light. By using the light-emitting element 10 that emits light with a emission spectrum in the wavelength range of 380 nm to 485 nm, particularly emitting light with a emission peak wavelength in the range of 420 nm to 470 nm, the emitted light can be utilized more effectively. Therefore, a light-emitting device with high luminous efficiency can be provided.

[0059] The content of the first phosphor 71 relative to, for example, resin (100 parts by mass) can be set to 1 part by mass or more and 50 parts by mass or less, preferably 2 parts by mass or more and 40 parts by mass or less.

[0060] The fluorescent component 50 preferably includes a second phosphor 72 whose emission peak wavelength is different from that of the first phosphor 71. For example, the light-emitting device 100 appropriately includes: a light-emitting element 10 that has an emission spectrum in a wavelength range of 380 nm to 485 nm, particularly emitting light with an emission peak wavelength in a range of 420 nm to 470 nm; a first phosphor 71 and a second phosphor 72 containing an aluminate phosphor of an embodiment of the present invention excited by the light; thereby, the light-emitting device 100 can be configured to have a wider color reproduction range and higher color rendering.

[0061] As a second phosphor 72, it only needs to absorb light from the light-emitting element 10 and change the wavelength to a different wavelength than that of the first phosphor 71. Examples include: (Ca, Sr, Ba)₂SiO₄; Eu, (Y, Gd, Lu)₃(Ga, Al)₅O₂. 12 : Ce, (Si, Al)6(O, N)8: Eu, SrGa2S4: Eu, K2SiF6: Mn, (Ba, Ca, Sr)2Si5N8: Eu, CaAlSiN3: Eu, (Ca, Sr)AlSiN3: Eu, (Ca, Sr, Ba)8MgSi4O 16 (F, Cl, Br)2: Eu, (Y, La)3Si6N 11 Ce, Ca3Sc2Si3O 12 Ce, CaSc4O4:Ce, etc.

[0062] When the fluorescent component 50 also includes a second phosphor 72, the second phosphor 72 is preferably a red phosphor that emits red light, preferably absorbing light in the wavelength range of 380 nm to 485 nm and emitting light in the wavelength range of 610 nm to 780 nm. By including a red phosphor in the light-emitting device, it is more suitable for applications such as lighting devices and liquid crystal display devices.

[0063] Examples of red phosphors include tetravalent Mn-activated fluoride phosphors with the composition K2SiF6:Mn, and divalent Eu-activated nitride phosphors with the composition CaSiAlN3:Eu, (Ca,Sr)AlSiN3:Eu, and SrLiAl3N4:Eu. Among these phosphors, from the viewpoint of improving color purity and expanding the color reproduction range, tetravalent Mn-activated fluoride phosphors with a half-width of 20 nm or less in their emission spectrum are preferred for red phosphors.

[0064] The first phosphor 71 and the second phosphor 72 (hereinafter collectively referred to as "phosphor 70") together with the sealing material constitute the fluorescent component 50 covering the light-emitting element. Examples of sealing materials constituting the fluorescent component 50 include silicone resin and epoxy resin.

[0065] The total content of phosphor 70 in the fluorescent component 50, relative to, for example, resin (100 parts by mass), can be set to 5 parts by mass or more and 300 parts by mass or less, preferably 10 parts by mass or more and 250 parts by mass or less, more preferably 15 parts by mass or more and 230 parts by mass or less, and even more preferably 15 parts by mass or more and 200 parts by mass or less. When the total content of phosphor in the fluorescent component 50 is within the above range, the light emitted from the light-emitting element 10 can be efficiently wavelength-converted using the phosphor 70.

[0066] The fluorescent component 50 may contain not only sealing material and phosphor 70, but also fillers, light-diffusing materials, etc. For example, by including light-diffusing materials, the directivity from the light-emitting element 10 can be mitigated, and the viewing angle can be increased. Examples of fillers include silicon dioxide, titanium dioxide, zinc oxide, zirconium oxide, and aluminum oxide. When the fluorescent component 50 contains fillers, the filler content relative to, for example, resin (100 parts by mass) can be set to 1 part by mass or 20 parts by mass.

[0067] Method for manufacturing aluminate phosphors

[0068] Next, a third embodiment of the present invention will describe a method for manufacturing an aluminate phosphor according to the first embodiment of the present invention. The aluminate phosphor can be manufactured using a compound containing elements constituting the elements of an aluminate phosphor.

[0069] Compounds containing elements that constitute aluminate phosphors

[0070] Compounds containing elements that constitute aluminate fluorophores include compounds containing aluminum (Al), compounds containing barium (Ba), compounds containing strontium (Sr) as needed, compounds containing magnesium (Mg), or compounds containing manganese (Mn).

[0071] aluminum-containing compounds

[0072] Examples of aluminum-containing compounds include: oxides, hydroxides, nitrides, nitrogen oxides, fluorides, and chlorides containing Al. These compounds can also be hydrates. As aluminum-containing compounds, aluminum metal monomers or aluminum alloys can be used, or metal monomers or alloys can be used to replace at least a portion of the compound.

[0073] Examples of Al-containing compounds include Al₂O₃, Al(OH)₃, AlN, AlON, AlF₃, and AlCl₃. Al-containing compounds can be used alone or in combination of two or more. Oxides (Al₂O₃) are preferred. This is because, compared to other materials, oxides do not contain elements other than those required for the target composition of aluminate phosphors, making it easier to obtain phosphors that meet the target composition. Furthermore, when using compounds containing elements other than those required for the target composition, residual impurity elements may sometimes be present in the resulting phosphor. These residual impurity elements are related to luminescence and act as suppressive factors, potentially significantly reducing luminescence intensity.

[0074] Barium-containing compounds

[0075] Examples of barium-containing compounds include: oxides, hydroxides, carbonates, nitrates, sulfates, carboxylates, halides, and nitrides containing Ba. These barium-containing compounds can also be in the form of hydrates. Specifically, examples include: BaO, Ba(OH)₂·8H₂O, BaCO₃, Ba(NO₃)₂, BaSO₄, Ba(OCO)₂·2H₂O, Ba(OCOCH₃)₂, BaCl₂·6H₂O, Ba₃N₂, and BaNH. A single Ba-containing compound can be used, or two or more can be used in combination. Among these compounds, carbonates and oxides are preferred from the perspective of ease of handling. They exhibit good stability in air, are easily decomposed by heating, and are less likely to leave residues of elements other than the target composition, thus easily suppressing the decrease in luminescence intensity caused by residual impurity elements. Therefore, Ba-containing carbonates (BaCO₃) are more preferred.

[0076] Strontium-containing compounds

[0077] Examples of Sr-containing compounds include oxides, hydroxides, carbonates, nitrates, sulfates, carboxylates, halides, and nitrides. These Sr-containing compounds can also be in the form of hydrates. Specifically, examples include SrO, Sr(OH)₂·8H₂O, SrCO₃, Sr(NO₃)₂·4H₂O, SrSO₄, Sr(OCO)₂·H₂O, Sr(OCOCH₃)₂·0.5H₂O, SrCl₂·6H₂O, Sr₃N₂, and SrNH. Sr-containing compounds can be used alone or in combination of two or more. Among these compounds, carbonates and oxides are preferred from the perspective of ease of handling. They exhibit good stability in air, are easily decomposed by heating, and are less likely to leave residues of elements other than the target composition, thus easily suppressing the reduction in luminescence intensity caused by residual impurity elements. Therefore, Sr-containing carbonates (SrCO₃) are more preferred.

[0078] Compounds containing magnesium

[0079] Examples of magnesium-containing compounds include oxides, hydroxides, carbonates, nitrates, sulfates, carboxylates, halides, and nitrides. These magnesium-containing compounds can also be hydrates. Specifically, examples include: MgO, Mg(OH)₂, 3MgCO₃·Mg(OH)₂·3H₂O, MgCO₃·Mg(OH)₂·nH₂O, Mg(NO₃)₂·6H₂O, MgSO₄, Mg(OCO)₂·H₂O, Mg(OCOCH₃)₂·4H₂O, MgCl₂, Mg₃N₂, and MgNH. A single Mg-containing compound can be used, or two or more can be used in combination. Among these compounds, carbonates and oxides are preferred from the perspective of ease of handling. They exhibit good stability in air, are easily decomposed by heating, and are less likely to leave residues of elements other than the target composition, thus easily suppressing the reduction in luminescence intensity caused by residual impurity elements. Therefore, Mg oxides (MgO) are more preferred.

[0080] Compounds containing manganese

[0081] Examples of manganese-containing compounds include oxides, hydroxides, carbonates, nitrates, sulfates, carboxylates, halides, and nitrides containing Mn. These manganese-containing compounds can also be in the form of hydrates. Specifically, examples include: MnO2, Mn2O2, Mn3O4, MnO, Mn(OH)2, MnCO3, Mn(NO3)2, Mn(OCOCH3)2·2H2O, Mn(OCOCH3)3·nH2O, MnCl2·4H2O, etc. Mn-containing compounds can be used alone or in combination of two or more. Among these compounds, carbonates and oxides are preferred from the perspective of ease of handling. They exhibit good stability in air, are easily decomposed by heating, and are less likely to leave residues of elements other than the target composition, thus easily suppressing the reduction in luminescence intensity caused by residual impurity elements. Therefore, Mn-containing carbonates (MnCO3) are more preferred.

[0082] Mixture of compounds

[0083] In the method for manufacturing an aluminate phosphor according to the third embodiment of the present invention, a compound selected from at least one compound containing Ba and a compound containing Sr, a compound containing Mg, a compound containing Mn, and a compound containing Al are mixed to obtain a raw material mixture, wherein the molar ratio of Al is set to 10, the total molar ratio of a first element containing one or more elements selected from Ba and Sr is set as variable a, the total molar ratio of a second element containing Mg and Mn is set as variable b, the molar ratio of Sr is set as the product of variable m and variable a, and the molar ratio of Mn is set as the product of variable n and variable b, and variables a and b are numbers that satisfy the following condition (1), variable m is a number that satisfies the following condition (2), and variable n is a number that satisfies the following condition (3).

[0084] 0.5<b<a≤0.5b+0.5<1.0 (1)

[0085] 0≤m≤1.0 (2)

[0086] 0.4≤n≤0.7 (3)

[0087] It is preferable to mix the compounds containing each element in such a way that variables a and b satisfy the following condition (4).

[0088] 0.7<b<a≤0.5b+0.5<1.0 (4)

[0089] By making variable b greater than 0.7, and variables a and b being numbers that satisfy the above condition (4), the crystal structure of the aluminate phosphor is more stable, and the luminescence intensity of the obtained aluminate phosphor can be improved.

[0090] The preferred variable n satisfies the condition 0.4≤n≤0.6, or the product of variable b and variable n (b×n) is a number that satisfies the condition 0.3<b×n<0.6.

[0091] Therefore, the Mn activation amount can be set to the optimal range to promote the absorption of light in the near-ultraviolet to blue region contained in the excitation light source, suppress the concentration quenching caused by excessive Mn activation amount, and improve the luminescence intensity. The luminescence intensity can be further improved by excitation with light in the near-ultraviolet to blue region.

[0092] The raw material mixture may also contain fluxes such as halides, as needed. By including fluxes in the raw material mixture, the reaction between the raw materials is promoted, and the solid-phase reaction proceeds more readily and uniformly. This is because the temperature at which the raw material mixture is heat-treated is approximately the same as, or higher than, the formation temperature of the liquid phase of the flux such as halides; therefore, it is considered to promote the reaction.

[0093] Examples of halides include rare earth metals, alkaline earth metals, fluorides of alkali metals, and chlorides. When using alkaline earth metal halides as fluxes, fluxes can also be added as components of the desired aluminate phosphor. Specifically, examples of fluxes include barium fluoride (BaF2), strontium fluoride (SrF2), magnesium fluoride (MgF2), aluminum fluoride (AlF3), manganese fluoride (MnF2), and calcium fluoride (CaF2). Magnesium fluoride (MgF2) is preferred because its crystalline structure is stable when used as a flux.

[0094] When the raw material mixture contains a flux, the flux content, based on the raw material mixture (100% by mass), is preferably 10% by mass or less, more preferably 5% by mass or less, and more preferably 0.1% by mass or more. This is because when the flux content is within the above range, there is too little flux, and therefore, due to insufficient particle growth, it is difficult to form a crystalline structure; conversely, if there is too much flux, it is also difficult to form a crystalline structure.

[0095] The raw material mixture can be weighed according to the desired proportions, containing compounds of each element, and then pulverized and mixed using a dry pulverizer such as a ball mill, vibratory mill, hammer mill, roller mill, or inkjet printer. Alternatively, it can be pulverized and mixed using mortars and pestles, or mixed using a mixer such as a belt mixer, Henschel mixer, or V-type mixer. A combination of dry pulverizer and mixer can also be used. Furthermore, mixing can be performed dry or wet by adding solvents. Dry mixing is preferred because it shortens process time and increases productivity compared to wet mixing.

[0096] Heat treatment of raw material mixture

[0097] The raw material mixture can be added to crucibles, boats, or other containers made of carbon materials such as graphite, boron nitride (BN), alumina, tungsten (W), or molybdenum (Mo) for heat treatment.

[0098] From the viewpoint of the stability of the crystal structure, the temperature for heat treatment of the raw material mixture is preferably 1000℃ to 1800℃, more preferably 1100℃ to 1750℃, even more preferably 1200℃ to 1700℃, and particularly preferably 1300℃ to 1650℃.

[0099] The heat treatment time varies depending on the heating rate, the heat treatment atmosphere, etc. After reaching the heat treatment temperature, it is preferably 1 hour or more, more preferably 2 hours or more, even more preferably 3 hours or more, preferably 20 hours or less, more preferably 18 hours or less, and even more preferably 15 hours or less.

[0100] The heat treatment of the raw material mixture can be carried out in an inert atmosphere such as argon or nitrogen, a reducing atmosphere containing hydrogen, or an oxidizing atmosphere such as the atmosphere. The raw material mixture is preferably heat-treated in a reducing nitrogen atmosphere to obtain a phosphor. The heat treatment atmosphere for the raw material mixture is more preferably a nitrogen atmosphere containing reducing hydrogen.

[0101] Aluminate phosphors exhibit good reactivity of the raw material mixture in a reducing atmosphere containing hydrogen and nitrogen, allowing for heat treatment at atmospheric pressure without pressurization. Heat treatment can be performed using, for example, electric furnaces or gas furnaces.

[0102] Post-processing

[0103] The obtained phosphors can also undergo post-processing steps such as wet dispersion, wet sieving, dehydration, drying, and dry sieving to obtain phosphors with the desired average particle size. For example, after heat treatment, the phosphors are dispersed in a solvent, and the dispersed phosphors are placed on a sieving machine. While various vibrations are applied to the sieving machine, the solvent flow is passed through it, and the calcined material is wet-sieved through a mesh. Then, it is dehydrated, dried, and sieved through a dry sieving machine to obtain phosphors with the desired average particle size.

[0104] By dispersing the heat-treated phosphor in a medium, calcination residues and other impurities from the flux, as well as unreacted components from the raw materials, can be removed. Alumina balls or zirconia balls, etc., can also be used as dispersion media in wet dispersion.

[0105] Example

[0106] The present invention will be described in more detail below through examples.

[0107] Example 1

[0108] The molar ratio of feed is determined by (Ba) 0.5 Sr 0.5 ) 0.92 (Mg 0.4 Mn 0.6 ) 0.85 Al 10 O 16.77 The composition is as follows: 36.6g of BaCO3 (BaCO3 content: 99.3% by mass), 27.4g of SrCO3 (SrCO3 content: 99.0% by mass), 204.9g of Al2O3 (Al2O3 content: 99.5% by mass), 4.0g of MgO (MgO content: 98.0% by mass), 24.7g of MnCO3 (MnCO3 content: 94.8% by mass), and 2.5g of MgF2 as a flux are dry-mixed to obtain a raw material mixture.

[0109] The obtained raw material mixture was filled into an alumina crucible, covered, and heat-treated at 1500°C for 5 hours in a mixed atmosphere of 3% H2 and 97% N2 to obtain an aluminate phosphor.

[0110] Example 2

[0111] Besides being determined by the molar ratio of added ingredients (Ba) 0.5 Sr 0.5 ) 0.95 (Mg 0.6 Mn 0.4 ) 0.93 Al 10 O 16.88 The composition is as shown. As raw materials, 37.8g of BaCO3, 28.4g of SrCO3, 205.6g of Al2O3, 7.6g of MgO, 18.1g of MnCO3, and 2.5g of MgF2 were added as flux. The process was carried out in the same manner as in Example 1 to obtain an aluminate phosphor.

[0112] Example 3

[0113] Besides being determined by the molar ratio of added ingredients (Ba) 0.5 Sr 0.5 ) 0.95 (Mg 0.4 Mn 0.6 ) 0.93 Al 10 O 16.88The composition is as shown. As raw materials, 37.1g of BaCO3, 27.8g of SrCO3, 201.6g of Al2O3, 4.4g of MgO, 26.6g of MnCO3, and 2.5g of MgF2 were weighed as fluxes. The process was carried out in the same manner as in Example 1 to obtain an aluminate phosphor.

[0114] Example 4

[0115] Besides being determined by the molar ratio of added ingredients (Ba) 0.5 Sr 0.5 ) 0.92 (Mg 0.6 Mn 0.4 ) 0.85 Al 10 O 16.77 The composition is as shown. As raw materials, 37.2g of BaCO3, 27.9g of SrCO3, 208.6g of Al2O3, 6.9g of MgO, 16.8g of MnCO3, and 2.5g of MgF2 were weighed as fluxes. The process was carried out in the same manner as in Example 1 to obtain an aluminate phosphor.

[0116] Example 5

[0117] Besides being determined by the molar ratio of added ingredients (Ba) 0.5 Sr 0.5 ) 0.92 (Mg 0.3 Mn 0.7 ) 0.85 Al 10 O 16.77 The composition is as shown. As raw materials, 36.2g of BaCO3, 27.2g of SrCO3, 203.0g of Al2O3, 2.5g of MgO, 28.6g of MnCO3, and 2.5g of MgF2 were weighed as fluxes. The process was carried out in the same manner as in Example 1 to obtain an aluminate phosphor.

[0118] Comparative Example 1

[0119] Besides being determined by the molar ratio of added ingredients (Ba) 0.5 Sr 0.5 ) 0.95 (Mg 0.8 Mn 0.2 ) 0.93 Al 10 O 16.88The composition is as shown. As raw materials, 38.6g of BaCO3, 29.0g of SrCO3, 209.8g of Al2O3, 10.9g of MgO, 9.2g of MnCO3, and 2.5g of MgF2 were weighed as fluxes. The process was carried out in the same manner as in Example 1 to obtain an aluminate phosphor.

[0120] Comparative Example 2

[0121] Besides being determined by the molar ratio of added ingredients (Ba) 0.5 Sr 0.5 ) 1.00 (Mg 0.4 Mn 0.6 ) 1.00 Al 10 O 17.00 The composition is as shown. As raw materials, 38.3g of BaCO3, 28.8g of SrCO3, 197.7g of Al2O3, 4.8g of MgO, 28.1g of MnCO3, and 2.4g of MgF2 were weighed as fluxes. The process was carried out in the same manner as in Example 1 to obtain an aluminate phosphor.

[0122] Comparative Example 3

[0123] Besides being determined by the molar ratio of added ingredients (Ba) 0.5 Sr 0.5 ) 0.95 (Mg 0.2 Mn 0.8 ) 0.93 Al 10 O 16.88 The composition is as shown. As raw materials, 36.4g of BaCO3, 27.3g of SrCO3, 197.8g of Al2O3, 1.4g of MgO, 34.8g of MnCO3, and 2.4g of MgF2 were weighed as fluxes. The process was carried out in the same manner as in Example 1 to obtain an aluminate phosphor.

[0124] Evaluation of luminescent properties

[0125] Relative luminous intensity (%)

[0126] The luminescence properties of the phosphors in the Examples and Comparative Examples were measured. Using a quantum efficiency measuring apparatus (manufactured by Otsuka Electronics Co., Ltd., QE-2000), each phosphor was irradiated with light of an excitation wavelength of 450 nm, and the emission spectra at room temperature (25℃±5℃) were measured. The luminescence intensity (%) of the obtained emission spectra was calculated. The relative luminescence intensity was calculated with the luminescence intensity of the phosphor in Comparative Example 1 as 100%. The results are shown in Table 1. Furthermore, for the aluminate phosphors of Example 1 and Comparative Example 1, Figure 2 The emission spectrum of relative luminescence intensity (%) is shown relative to wavelength.

[0127] Half-width: FWHM

[0128] For the phosphors of the examples and comparative examples, the half-width (FWHM) of the obtained emission spectra was measured. The results are shown in Table 1.

[0129] peak wavelength of emission

[0130] For the phosphors of the examples and comparative examples, the wavelength of the obtained emission spectrum with the largest wavelength was used as the emission peak wavelength (nm) for measurement. The results are shown in Table 1.

[0131] Reflectance (%)

[0132] For the phosphors of the examples and comparative examples, a spectrophotometer (Hitachi High-Technologies, F-4500) was used. The sample was irradiated with light from a halogen lamp serving as the excitation source at room temperature (25°C ± 5°C). The wavelengths of the spectrometers on both the excitation and fluorescence sides were scanned together, and the reflected light was measured. The ratio of reflected light to light at the excitation wavelength of 450 nm, based on the reflectance of CaHPO4, is shown as reflectance (%) in Table 1. Furthermore, for the phosphors of the examples and Comparative Example 1, the reflectance relative to wavelength is shown as the reflectance spectrum. Figure 3 .

[0133] Table 1

[0134]

[0135] As shown in Table 1, in the aluminate phosphors of Examples 1-5, when the molar ratio of Al is set to 10, the values ​​of variables a, b, m, and n satisfy conditions (1) to (3). In these Examples 1-5, the relative luminescence intensity is higher when excited by blue light with a peak emission wavelength of 450 nm compared to the aluminate phosphors of Comparative Examples 1-3. In particular, in the aluminate phosphors of Examples 1-4, when the molar ratio of Al is set to 10, the variable n representing the molar ratio of Mn in the second element (Mg and Mn) satisfies the condition 0.4 ≤ n ≤ 0.6, and the product (b × n) of the variable n representing the molar ratio of Mn and the variable b satisfies the condition 0.3 < b × n < 0.6. Therefore, the relative luminescence intensity is extremely high, exceeding 135%, when excited by blue light with a peak emission wavelength of 450 nm. Furthermore, as shown in Table 1, the reflectance of blue light with a peak emission wavelength of 450 nm, which serves as the excitation light, in the aluminate phosphors of Examples 1-5 is as low as 80% or less. Based on these results, it can be confirmed that the aluminate phosphors of Examples 1-5 absorb a significant portion of the blue light with a peak emission wavelength of 450 nm, which serves as the excitation light, and emit fluorescence with a high emission intensity.

[0136] As shown in Table 1, in the composition of the aluminate phosphor of Comparative Example 1, the variable n, representing the molar ratio of Mn in the second element (Mg and Mn), does not satisfy the condition 0.4 ≤ n ≤ 0.7 (3). In this Comparative Example 1, the reflectance exceeds 80%, which is higher than that of the aluminate phosphors of Examples 1 to 5. In other words, the absorption rate of the excitation light with a peak emission wavelength of 450 nm is lower, and the relative luminescence intensity is lower compared with that of the aluminate phosphors of Examples 1 to 5.

[0137] Furthermore, as shown in Table 1, in Comparative Example 2, the variable 'a' representing the total molar ratio of the first element (Ba, Sr) and the variable 'b' representing the total molar ratio of the second element (Mg and Mn) are equal in composition, and condition (1) is not satisfied. In this Comparative Example 2, the relative luminescence intensity is lower.

[0138] Furthermore, as shown in Table 1, in the composition of the aluminate phosphor of Comparative Example 3, the variable n, representing the molar ratio of Mn in the second element (Mg and Mn), does not satisfy the condition 0.4 ≤ n ≤ 0.7 (3), and the variable n is relatively large, exceeding the upper limit of 0.7. The relative luminescence intensity of Comparative Example 3 is extremely low, down to 13%.

[0139] Furthermore, in the compositions of the aluminate fluorophores in Comparative Examples 1 to 3, the product (b×n) of the variables n and b, which represent the molar ratio of Mn, does not satisfy the condition 0.3 < b×n < 0.6.

[0140] In addition, as shown in Table 1, the half-width of the emission peak in the emission spectrum of the aluminate phosphors in Examples 1 to 5 is narrowed to less than 30 nm.

[0141] As shown in Table 1 and Figure 2 As shown, the aluminate phosphors of Examples 1-5, when excited by blue light with a peak emission wavelength of 450 nm, emit light with a peak emission wavelength in the range of 516 nm to 518 nm. Additionally, as... Figure 2 As shown in the emission spectrum, the relative emission intensity of the aluminate phosphor of Example 1 at the emission peak wavelength is higher than that of Comparative Example 1.

[0142] In addition, such as Figure 3 As shown, it can be confirmed that the reflectance spectrum in the range of 420 nm to 470 nm of the aluminate phosphor of Example 1 is lower than that of the aluminate phosphor of Comparative Example 1. In particular, the absorption of excitation light with wavelengths of 420 nm to 470 nm is higher, and the phosphor absorbs excitation light in this wavelength range and emits fluorescence with higher luminescence intensity.

[0143] Industrial applicability

[0144] According to the present invention, an aluminate phosphor with high luminescence intensity can be provided as a green luminescent phosphor excited by light in the near-ultraviolet to blue region. Light-emitting devices using this aluminate phosphor are commonly used in a wide range of fields such as lighting, automotive lighting, displays, backlights for liquid crystal displays, signal controllers, and illuminated switches. The aluminate phosphor of one embodiment of the present invention has high luminescence intensity, a narrow half-width at half-maximum (WWHM) of the emission peak, and high color purity; therefore, it can expand the color reproduction range and is suitable for use as a backlight source for liquid crystal displays.

Claims

1. An aluminate phosphor having a composition comprising a first element and a second element, wherein the first element contains Ba and Sr, and the second element contains Mg and Mn. In the composition of the aluminate phosphor, when the molar ratio of Al is set to 10, the total molar ratio of the first element is variable a, the total molar ratio of the second element is variable b, the molar ratio of Sr is the product of variable m and variable a, and the molar ratio of Mn is the product of variable n and variable b. in, The variables a and b satisfy the following condition (4), the variable m satisfies the following condition (2), and the variable n satisfies the following condition (3). 0.7<b<a≤0.5b+0.5<1.0 (4) 0＜m≤1.0 (2) 0.4≤n≤0.7 (3)， The aluminate phosphor absorbs light in the wavelength range of 380 nm to 485 nm and emits light with a peak emission wavelength in the range of 485 nm to 570 nm.

2. The aluminate phosphor as described in claim 1, wherein, The aluminate phosphor has a composition represented by the following formula (I), (Ba 1-m ,Sr m ) a (Mg 1-n ,Mn n ) b Al 10 O 15＋a＋b (I) In the formula, a, b, m, and n are numbers that satisfy 0.5 < b < a ≤ 0.5b + 0.5 < 1.0, 0 < m ≤ 1.0, and 0.4 ≤ n ≤ 0.

7.

3. The aluminate phosphor according to claim 1, wherein, The first element is Ba and Sr, and the second element is Mg and Mn.

4. The aluminate phosphor according to claim 1 or 2, wherein, The variable n is a number that satisfies the condition 0.4≤n≤0.

6.

5. The aluminate phosphor according to claim 1 or 2, wherein, The half-width of the emission peak in the emission spectrum excited by light with an emission peak wavelength of 450 nm is less than 45 nm.

6. A light-emitting device comprising an aluminate phosphor and an excitation light source as described in claim 1 or 2.

7. The light-emitting device as claimed in claim 6, wherein, The excitation light source has a emission spectrum in the range of 380 nm to 485 nm.

8. The light-emitting device as claimed in claim 6, wherein, The excitation light source has a peak emission wavelength in the range of above 420nm and below 470nm.

9. A method for manufacturing an aluminate phosphor, the aluminate phosphor having a composition comprising a first element, a second element, Al, and O, wherein the first element contains Ba and Sr, and the second element contains Mg and Mn. The method for manufacturing the aluminate phosphor includes mixing a compound containing the elements in the following manner, and then heat-treating the resulting raw material mixture: When the molar ratio of Al in the composition is set to 10, the total molar ratio of the first element is variable a, the total molar ratio of the second element is variable b, the molar ratio of Sr is the product of variable m and variable a, and the molar ratio of Mn is the product of variable n and variable b. Furthermore, variables a and b satisfy the following condition (4), variable m satisfies the following condition (2), and variable n satisfies the following condition (3). 0.7<b<a≤0.5b+0.5<1.0 (4) 0＜m≤1.0 (2) 0.4≤n≤0.7 (3), The product (b×n) of the variable b and the variable n is a number that satisfies the condition 0.3 < b×n < 0.

6. The aluminate phosphor absorbs light in the wavelength range of 380 nm to 485 nm and emits light with a peak emission wavelength in the range of 485 nm to 570 nm.

10. The method for manufacturing an aluminate phosphor as described in claim 9, wherein, The resulting aluminate phosphor has the composition represented by the following formula (I). (Ba 1-m ,Sr m ) a (Mg 1-n ,Mn n ) b Al 10 O 15＋a＋b (I) In the formula, a, b, m, and n are numbers that satisfy 0.5 < b < a ≤ 0.5b + 0.5 < 1.0, 0 < m ≤ 1.0, and 0.4 ≤ n ≤ 0.7.

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