Oxide phosphor, light-emitting device, and method for producing oxide phosphor

Abstract

To provide an oxide-based phosphor having an emission peak wave length of 800nm or longer.SOLUTION: A molar ratio of Mg or a total molar ratio of Mg and the first element M1 is in a range of 0.7 or more and 1.3 or less when a total molar ratio of Ga, Cr, the second element M2, and the third element M3 in 1 mol of the composition of the fluorescent material is 2, and the fluorescent material contains Mg, Ga, O, and Cr, and optionally contains the first element M2, the second element M3, and the third element M1. The molar ratio of O is in a range of 3.7 or more and 4.3 or less, the molar ratio of Cr is in a range of more than 0.02 and 0.3 or less, and the light emission peak wavelengths are in a range of 800nm or more and 1600nm or less in the light emission spectrum.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to an oxide phosphor, a light-emitting device, and a method for producing the oxide phosphor. [Background technology]

[0002] Light-emitting devices with emission intensities in the wavelength range from red light to near-infrared light are desired for use in, for example, infrared cameras, infrared communications, light sources for plant growth and cultivation, vein authentication, which is a type of biometric authentication, food composition analysis equipment for non-destructively measuring the sugar content of foods such as fruits and vegetables, etc. Light-emitting devices that emit light in the wavelength range from red light to near-infrared light as well as in the wavelength range of visible light are also desired. Such light emitting devices include light emitting devices that combine a light emitting diode (LED) and a phosphor.

[0003] Patent Document 1 discloses a phosphorescent phosphor made of chromium-activated gallate that is used as a display or light source in dark places and emits light having an emission peak wavelength in the red light range of 660 nm to 720 nm when excited by ultraviolet light of 254 nm. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-259375 Summary of the Invention [Problem to be solved by the invention]

[0005] Light sources used in small analytical instruments for medical or food applications may require emission with a peak wavelength in the near-infrared region exceeding 720 nm. An object of the present disclosure is to provide an oxide phosphor having an emission peak wavelength in the near-infrared wavelength range of 800 nm or more, a light-emitting device using the same, and a method for producing the oxide phosphor. [Means for solving the problem]

[0006] The first aspect is a composition containing Mg, Ga, O (oxygen), and Cr, and optionally containing at least one first element M selected from the group consisting of Ca, Sr, Ba, Ni, and Zn. 1 and at least one second element M selected from the group consisting of B, Al, In, and Sc. 2 and at least one third element M selected from the group consisting of Eu, Ce, Tb, Pr, Nd, Sm, Yb, Ho, Er, Tm, and Mn. 3 and wherein the Ga, the Cr and the second element M in 1 mole of the composition of the oxide phosphor are 2 and the third element M 3 When the total molar ratio of Mg and the first element M is 2, 1 When the compound contains Mg and the first element M 1 the molar ratio of O is in the range of 3.7 to 4.3, the molar ratio of Cr is in the range of more than 0.02 to 0.3, and further the molar ratio of Mg and the first element M 1 The molar ratio of the first element M when the total of 1 The molar ratio of the second element M is in the range of 0 to 0.8. 2 The molar ratio of the third element M is in the range of 0 to 1.6. 3 The molar ratio of the third element M is in the range of 0 to 0.2. 3 The molar ratio of is smaller than the molar ratio of Cr, and the phosphor has an emission peak wavelength in the range of 800 nm to 1600 nm in its emission spectrum.

[0007] A second aspect is a light emitting device comprising the oxide phosphor and a light emitting element having an emission peak wavelength in the range of 365 nm to 500 nm, and irradiating the oxide phosphor.

[0008] The third aspect is a composition comprising a first compound containing Mg, a second compound containing Ga, a third compound containing Cr, and, if necessary, at least one first element M selected from the group consisting of Ca, Sr, Ba, Ni, and Zn. 1 and a fourth compound containing at least one second element M selected from the group consisting of B, Al, In, and Sc. 2 and at least one third element M selected from the group consisting of Eu, Ce, Tb, Pr, Nd, Sm, Yb, Ho, Er, Tm, and Mn. 3 and a sixth compound containing Ga, Cr, the second element M in 1 mole of the oxide phosphor composition. 2 and the third element M 3 When the total molar ratio of Mg or the first element M is 2, 1 When it contains Mg and the first element M 1 the total molar ratio of Mg and the first element M is in the range of 0.7 to 1.3, the molar ratio of Cr is in the range of more than 0.02 to 0.3, 1 The molar ratio of the first element M when the total of 1 The molar ratio of the second element M 2 The molar ratio of the third element M 3 The molar ratio of the third element M 3 preparing a raw material mixture by adjusting and mixing the first compound, the second compound, the third compound, and, as necessary, the fourth compound, the fifth compound, or the sixth compound so that the molar ratio of Cr is smaller than the molar ratio of Cr; and heat-treating the raw material mixture at a temperature in the range of 1200°C to 1700°C in an oxygen-containing atmosphere to obtain an oxide phosphor, wherein at least one compound selected from the group consisting of the first compound, the second compound, and the third compound is an oxide. [Effects of the Invention]

[0009] According to one aspect of the present disclosure, it is possible to provide an oxide phosphor having an emission peak wavelength in the near-infrared wavelength range of 800 nm or more and 1600 nm or less, a light-emitting device using the same, and a method for producing the oxide phosphor. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a first configuration example of a light emitting device. [Figure 2] FIG. 2 is a schematic cross-sectional view showing another example of the first configuration example of the light emitting device. [Figure 3A] FIG. 3A is a schematic plan view showing a second configuration example of the light emitting device. [Figure 3B] FIG. 3B is a schematic cross-sectional view showing a second configuration example of the light emitting device. [Figure 4] FIG. 4 is an SEM photograph of the oxide phosphor according to Example 3. [Figure 5] FIG. 5 is a diagram showing the emission spectra of the oxide phosphors according to Examples 1 to 3. [Figure 6] FIG. 6 is a diagram showing the emission spectra of the oxide phosphors according to Examples 4 to 6. [Figure 7] FIG. 7 is a diagram showing the emission spectra of the oxide phosphors according to Examples 7 to 9. [Figure 8] FIG. 8 is a diagram showing the emission spectra of the oxide phosphors according to Examples 10 to 12. [Figure 9] FIG. 9 is a diagram showing the emission spectra of the oxide phosphors according to Examples 13 to 15. [Figure 10] FIG. 10 is a diagram showing the absorption spectrum of the oxide phosphor according to Example 3. [Figure 11] FIG. 11 is a diagram showing the emission spectra of the oxide phosphors according to Comparative Examples 1 and 2. As shown in FIG. [Figure 12] FIG. 12 is a diagram showing the emission spectra of the oxide phosphors according to Comparative Examples 3 and 4. As shown in FIG. [Figure 13] FIG. 13 is a diagram showing the emission spectra of the light emitting devices according to Examples 1 and 2. As shown in FIG. [Figure 14] FIG. 14 is a diagram showing the emission spectra of the oxide phosphors according to Examples 16 to 18. [Figure 15] FIG. 15 is a diagram showing the emission spectra of the oxide phosphors according to Examples 19 to 21. [Figure 16] FIG. 16 is a diagram showing the emission spectra of the oxide phosphors according to Examples 22 to 24. DETAILED DESCRIPTION OF THE INVENTION

[0011] The oxide phosphor according to the present disclosure, a light-emitting device using the same, and a method for manufacturing the oxide phosphor are described below. However, the following embodiments are merely examples for embodying the technical concept of the present invention, and the present invention is not limited to the oxide phosphor, light-emitting device, and method for manufacturing the oxide phosphor described below. Note that, for visible light, the relationship between color names and chromaticity coordinates, the relationship between light wavelength ranges and color names of monochromatic light, etc., conforms to JIS Z8110.

[0012] Light-emitting devices are required to emit light in an optimal wavelength range depending on the target and usage situation. For example, medical equipment used in medical settings and for daily health management may be required to easily obtain information about the inside of a living body. The inside of a living body contains light absorbers such as water, hemoglobin, and melanin. For example, hemoglobin has a high absorption rate for light in the visible wavelength range of less than 650 nm. Therefore, light-emitting devices emitting light in the visible wavelength range have difficulty transmitting light in the visible wavelength range into the living body, making it difficult to obtain information about the inside of a living body. Therefore, there is a range known as the "biological window" through which light easily penetrates the living body. There is a need for light-emitting devices that emit light in a highly transparent near-infrared wavelength range, for example, from 800 nm to 1300 nm, which includes at least a portion of this range. For example, if it were possible to measure increases or decreases in the oxygen concentration in blood in a living body by measuring the increase or decrease in light absorption by hemoglobin, which binds to oxygen, it would be possible to easily obtain information about the inside of a living body by irradiating light from a light-emitting device. Therefore, the phosphor used in the light emitting device may be required to have an emission peak wavelength in the range of 800 nm to 1300 nm, preferably 800 nm to 1200 nm, and more preferably 800 nm to 1000 nm.

[0013] For example, in the food industry, there is a demand for non-destructive sugar content meters that can non-destructively measure the sugar content of fruits and vegetables, as well as non-destructive rice taste meters. Near-infrared spectroscopy is sometimes used as a non-destructive method for measuring the internal quality of fruits and vegetables, such as sugar content, acidity, ripeness, and internal damage, as well as the surface quality that appears on the surface of the fruit and vegetable peel or the surface layer near the surface, such as abnormal dryness. Near-infrared spectroscopy irradiates fruits and vegetables with light in the near-infrared wavelength range, receives the transmitted light that passes through the fruit and vegetables, and receives the reflected light that is reflected by the fruit and vegetables, and measures the quality of the fruit and vegetables based on the decrease in light intensity (light absorption). Near-infrared spectroscopy analytical devices used in such food industry use light sources such as tungsten lamps and xenon lamps.

[0014] There are cases where light emitting devices are required that emit light in the wavelength range of 365 nm to 700 nm as well as in the wavelength range of 800 nm to 1600 nm. For example, there are cases where emission in the visible light wavelength range is required not only to obtain internal information about living organisms or fruits and vegetables, but also to improve the visibility of the target object.

[0015] The phosphorescent phosphor disclosed in the aforementioned Patent Document 1 is excited by, for example, 254 nm ultraviolet light and has an emission peak wavelength of 706 nm, which is less than 800 nm. Therefore, it is not possible to obtain sufficient light emission in the wavelength range of 800 nm or more and 1000 nm or less, which is necessary to obtain internal information about living organisms or fruits and vegetables. Furthermore, because the phosphorescent phosphor disclosed in the aforementioned Patent Document 1 is excited by, for example, 254 nm ultraviolet light, it may not emit enough light in the visible light wavelength range of 365 nm or more and less than 700 nm, which is necessary for visibility of objects.

[0016] oxide phosphor The oxide phosphor contains Mg, Ga, O (oxygen), and Cr. The oxide phosphor may further contain at least one first element M selected from the group consisting of Ca, Sr, Ba, Ni, and Zn, as needed. 1 and at least one second element M selected from the group consisting of B, Al, In, and Sc. 2 and at least one third element M selected from the group consisting of Eu, Ce, Tb, Pr, Nd, Sm, Yb, Ho, Er, Tm, and Mn. 3 In one mole of the oxide phosphor composition, Ga, Cr, and the second element M may be contained. 2 and the third element M 3 When the total molar ratio of Mg and Mg is 2, the molar ratio of the first element M 1 When it contains Mg and the first element M 1 The total molar ratio of Mg and the first element M is in the range of 0.7 or more and 1.3 or less. The molar ratio of O is in the range of 3.7 or more and 4.3 or less, and the molar ratio of Cr is in the range of more than 0.02 and 0.3 or less. 1 When the total molar ratio of the first element M is 1, 1 The molar ratio of the second element M is in the range of 0 to 0.8. 2The molar ratio of the third element M is in the range of 0 to 1.6. 3 The molar ratio of the third element M is in the range of 0 to 0.2. 3 The molar ratio of the first element M is smaller than the molar ratio of Cr. In the emission spectrum of the oxide phosphor, the emission peak wavelength is in the range of 800 nm to 1600 nm. 1 , second element M 2 and the third element M 3 may contain two or more elements.

[0017] An oxide phosphor in which each element has a molar ratio within the above range absorbs and is excited by light from a light source of 400 nm or more, and emits light having a peak emission wavelength in the range of 800 nm to 1600 nm. An oxide phosphor in which each element has a molar ratio within the above range, for example, an oxide phosphor having a composition represented by the following formula (1), has high absorbance in the ultraviolet wavelength range of 10 nm to 400 nm, specifically, light in the range of 240 nm to 260 nm, as well as light in the range of 400 nm to 450 nm, absorbs light in the range of 400 nm to 450 nm, and emits light having a peak emission wavelength in the range of 800 nm to 1600 nm. An oxide phosphor in which each element has a molar ratio within the above range also has high absorbance in the range of 550 nm to 600 nm, and can absorb and be excited by light in the range of 550 nm to 600 nm.

[0018] The oxide phosphor preferably has a composition included in the composition formula represented by the following formula (1). (Mg 1-t M 1 t ) u (Ga 1-v-x-y M 2 v )2O w :Cr x ,M 3 y (1) (In the formula (1), t, u, v, w, x, and y satisfy 0 ≦ t ≦ 0.8, 0.7 ≦ u ≦ 1.3, 0 ≦ v ≦ 0.8, 3.7 ≦ w ≦ 4.3, 0.02 ≦ x ≦ 0.3, 0 ≦ y ≦ 0.2, and y < x.)

[0019] The oxide phosphor contains a first element M 1 Preferably contains at least one element selected from the group consisting of Ca, Sr, Ni, and Zn, and the second element M 2 Preferably contains at least one element selected from the group consisting of Al and Sc, and the third element M 3 Preferably contains at least one element selected from the group consisting of Eu, Ce, Ni, and Mn.)

[0020] When the oxide phosphor has a composition included in the compositional formula represented by the formula (1), the molar ratio of Mg or the first element M 1 When including, the variable u representing the total molar ratio of Mg and the first element M 1 May satisfy 0.8 ≦ u ≦ 1.2, may satisfy 0.9 ≦ u ≦ 1.1, or may satisfy u = 1.0. When the oxide phosphor has a composition represented by the formula (1), the molar ratio of the first element M 1 Is represented by the product of the variable t and the variable u. When the total molar ratio of Mg and the first element M 1 Is taken as 1, the variable t may satisfy 0.1 ≦ t ≦ 0.7, may satisfy 0.2 ≦ t ≦ 0.6, or may satisfy 0.3 ≦ t ≦ 0.5.)

[0021] When the oxide phosphor contains Zn as the first element M 1 In 1 mole of the composition of the oxide phosphor, when the total molar ratio of the first element M 1 And Mg is taken as 1, the molar ratio of the first element M 1 Is preferably in the range of 0.1 or more and 0.5 or less. When the oxide phosphor contains Zn as the first element M 1 In 1 mole of the composition of the oxide phosphor, when the total molar ratio of the first element M 1 And Mg is taken as 1, the molar ratio of the first element M 1 Is in the range of 0.1 or more and 0.5 or less, and the second element M2 and the second element M 2 It is preferable that the oxide phosphor contains the first element M 1 Zn as the second element, M 2 When the oxide phosphor contains Al as the first element, and has a composition included in the composition formula represented by the formula (1), 1 is Zn, and the second element M 2 When the first element M is Al, the variable t preferably satisfies 0.1≦t≦0.5, and the variable v preferably satisfies 0.1≦v≦0.6, and more preferably satisfies 0.2≦v≦0.5. 1 When Zn is contained as the first element, Mg and the first element M are contained in the composition of the oxide phosphor. 1 When the total molar ratio of the first element M is 1, 1 When the molar ratio is within the above range, the emission spectrum has an emission peak wavelength in the range of 800 nm to 1600 nm.

[0022] The oxide phosphor contains the first element M 1 When Ni is contained as the first element M 1 When the molar ratio of the total of Mg and Mg is 1, the first element M 1 The molar ratio of is preferably in the range of 0.001 to 0.50, may be in the range of 0.002 to 0.30, or may be in the range of 0.005 to 0.20. When the oxide phosphor has a composition included in the composition formula represented by the formula (1), the first element M 1 When the first element M is Ni, the variable t preferably satisfies 0.001≦t≦0.50, may satisfy 0.002≦t≦0.30, or may satisfy 0.005≦t≦0.20. 1 When Ni is contained as the first element, Mg and the first element M are contained in the composition of the oxide phosphor. 1 When the total molar ratio of the first element M is 1, 1 When the molar ratio is within the above range, the emission spectrum has an emission peak wavelength in the range of 800 nm to 1600 nm.

[0023] When the oxide phosphor has a composition included in the compositional formula represented by the formula (1), the molar ratio of the second element M 2 is represented by the product of the variable v and 2. The variable v in the formula (1) satisfies 0 ≦ v ≦ 0.8, may satisfy 0.01 ≦ v ≦ 0.70, may satisfy 0.02 ≦ v ≦ 0.60, and may satisfy 0.05 ≦ v ≦ 0.50.

[0024] The molar ratio of O (oxygen) contained in the oxide phosphor is within the range of 3.7 or more and 4.3 or less, may be within the range of 3.8 or more and 4.2 or less, may be within the range of 3.9 or more and 4.1 or less, or may be 4.0, when the total of Ga, Cr, the second element M 2 and the third element M 3 is 2 in 1 mole of the composition of the oxide phosphor. When the oxide phosphor has a composition included in the compositional formula represented by the formula (1), in the formula (1), the variable w representing the molar ratio of O (oxygen) satisfies 3.7 ≦ w ≦ 4.3, may satisfy 3.8 ≦ w ≦ 4.2, may satisfy 3.9 ≦ w ≦ 4.1, or w = 4 may also be satisfied.

[0025] In the oxide phosphor, Cr is an activating element. When the oxide phosphor has a composition included in the compositional formula represented by the formula (1), the molar ratio of Cr is represented by the variable x. The variable x in the formula (1) satisfies 0.02 < x ≦ 0.3, may satisfy 0.03 ≦ x ≦ 0.25, and may satisfy 0.03 < x ≦ 0.20.

[0026] In the oxide phosphor, the third element M 3 is an activating element together with Cr. When the oxide phosphor has a composition included in the compositional formula represented by the formula (1), the molar ratio of the third element M 3 is represented by the variable y. The variable y in the formula (1) satisfies 0 ≦ y ≦ 0.20, may satisfy 0.001 ≦ y ≦ 0.20, may satisfy 0.002 ≦ y ≦ 0.15, and may satisfy 0.003 ≦ y ≦ 0.10. In order to emit light having a target emission peak wavelength, the third element M 3The molar ratio is smaller than the molar ratio of Cr. When the oxide phosphor has the composition represented by the above formula (1), the variable x representing the molar ratio of Cr and the third element M 3 The variable y representing the molar ratio of satisfies y < x.

[0027] The oxide phosphor has an emission peak wavelength within the range of 800 nm or more and 1600 nm or less in the emission spectrum as a phosphor by irradiation with light from a light source. When the oxide phosphor has an emission peak wavelength within the range of 800 nm or more and 1600 nm or less in the emission spectrum as a phosphor by irradiation with light from a light source, it becomes possible to measure the increase and decrease of light in the range of 800 nm or more and 1300 nm or less and the quality of foods such as fresh fruits and vegetables, and it can be used for a light source used in a small analytical instrument for medical or food use. The oxide phosphor may have an emission peak wavelength within the range of 810 nm or more and 1500 nm or less, may have an emission peak wavelength within the range of 820 nm or more and 1400 nm or less, may have an emission peak wavelength within the range of 820 nm or more and 1300 nm or less, may have an emission peak wavelength within the range of 820 nm or more and 1200 nm or less, may have an emission peak wavelength within the range of 830 nm or more and 1000 nm or less, or may have an emission peak wavelength within the range of 830 nm or more and 980 nm or less in the emission spectrum as a phosphor by irradiation with light from a light source.

[0028] The oxide phosphor preferably has an emission spectrum with a peak wavelength in the range of 800 nm to 1600 nm, and a full width at half maximum of the emission spectrum in the range of 150 nm to 350 nm, or alternatively in the range of 160 nm to 340 nm, or in the range of 170 nm to 330 nm. In this specification, the full width at half maximum refers to the wavelength range in the emission spectrum where the emission intensity is 50% of the emission intensity at the emission peak wavelength showing the maximum emission intensity. Light is absorbed and scattered in vivo, and to measure subtle changes in the propagation behavior of light in blood, it is preferable to irradiate light with a peak light having a wide full width at half maximum. Furthermore, even when measuring foods such as fruits and vegetables and rice nondestructively, it is preferable to irradiate light with a wide emission spectrum in order to obtain information about the interior of the food. Furthermore, regarding the appearance of the color of an object when irradiated with light (hereinafter also referred to as "color rendering"), it is desirable for the emission spectrum to have a wide wavelength range, and a wider full width at half maximum results in light with superior color rendering. For example, when used in a work place such as a factory, it may be required to emit light that does not disrupt the spectral balance of light so that workers can work easily.

[0029] When the oxide phosphor has an emission spectrum with a peak wavelength in the range of 800 nm to 1000 nm, the full width at half maximum of the emission spectrum is preferably 150 nm to 250 nm, more preferably 160 nm to 240 nm. The emission spectrum of the oxide phosphor may have a full width at half maximum of 160 nm or more, 170 nm or more, 180 nm or more, 190 nm or more, 250 nm or less, or 230 nm or less.

[0030] When the oxide phosphor has an emission spectrum with a peak wavelength in the range of more than 1000 nm to 1600 nm, for example, in the range of 1001 nm to 1600 nm, the full width at half maximum of the emission spectrum is preferably 150 nm to 350 nm, more preferably 180 nm to 340 nm, even more preferably 200 nm to 330 nm, and even more preferably 205 nm to 330 nm.

[0031] The oxide phosphor preferably has a central particle size (median diameter) Dm at 50% cumulative volume in the particle size distribution measured by a laser diffraction particle size distribution measurement method, and more preferably has a central particle size (median diameter) Dm of 5 μm to 50 μm, and more preferably has a central particle size (median diameter) Dm of 10 μm to 30 μm. When the central particle size of the oxide phosphor is within the range of 5 μm to 50 μm, it easily absorbs excitation light and easily emits light having an emission peak wavelength within the range of 800 nm to 1600 nm in the emission spectrum. The median diameter Dm can be measured, for example, using a laser diffraction particle size distribution measurement device (MASTER SIZER 3000, manufactured by MALVERN).

[0032] Light-emitting device The light emitting device includes an oxide phosphor and a light emitting element having an emission peak wavelength in the range of 365 nm to 500 nm and irradiating the oxide phosphor. The oxide phosphor can be used as a component constituting a wavelength conversion member together with a translucent material.

[0033] The light emitting device preferably includes, as a light emitting element that irradiates the oxide phosphor, an LED chip or an LD chip that uses, for example, a nitride-based semiconductor.

[0034] The light-emitting element has an emission peak wavelength in the range of 365 nm to 500 nm, preferably in the range of 370 nm to 490 nm, more preferably in the range of 375 nm to 480 nm, and even more preferably in the range of 380 nm to 470 nm. By using the light-emitting element as an excitation light source for the oxide phosphor, it is possible to construct a light-emitting device that emits a mixed color light of a desired wavelength range, consisting of light from the light-emitting element and fluorescence from a phosphor containing the oxide phosphor. The full width at half maximum of the emission peak in the emission spectrum of the light-emitting element can be, for example, 30 nm or less. It is preferable to use a light-emitting element using, for example, a nitride-based semiconductor. By using a light-emitting element using a nitride-based semiconductor as a light source, a stable light-emitting device can be obtained that is highly efficient, has high output-to-input linearity, and is resistant to mechanical shock.

[0035] The light emitting device essentially comprises a first phosphor containing the oxide phosphor described above, and may further comprise a different phosphor. In addition to the first phosphor, the light emitting device preferably comprises at least one phosphor selected from the group consisting of a second phosphor having a peak emission wavelength in the range of 455 nm or more and less than 495 nm, a third phosphor having a peak emission wavelength in the range of 495 nm or more and less than 610 nm, a fourth phosphor having a peak emission wavelength in the range of 610 nm or more and less than 700 nm, and a fifth phosphor having a peak emission wavelength in the range of 700 nm or more and less than 1050 nm, in the emission spectrum of each phosphor. The light emitting device more preferably comprises a first phosphor containing the oxide phosphor described above, and at least one phosphor selected from the group consisting of the third phosphor, the fourth phosphor, and the fifth phosphor. Furthermore, the light-emitting device preferably has an emission spectrum that is continuous within a range from the peak emission wavelength of the light-emitting element to 900 nm inclusive, with the maximum emission intensity within the range from the peak emission wavelength of the light-emitting element to 900 nm inclusive being 100%, and the minimum emission intensity within the range from the peak emission wavelength of the light-emitting element to 900 nm inclusive being 3% or more. The emission spectrum of the light-emitting device being continuous within a range from the peak emission wavelength of the light-emitting element to 900 nm inclusive means that the emission intensity of the emission spectrum does not reach 0% throughout the entire wavelength range from the peak emission wavelength of the light-emitting element to 900 nm inclusive, and the emission spectrum is continuous without interruption. Depending on the measurement or detection target, such as in vivo or in fruits and vegetables, a light source that emits light having an emission spectrum ranging from visible light to a portion of near-infrared light may be required. When a tungsten lamp or xenon lamp is used as the light source, light having a continuous emission spectrum is emitted without interruption from the visible light to a portion of near-infrared light. However, using a tungsten lamp or xenon lamp as the light source makes it difficult to miniaturize the device.A light-emitting device that emits light with a continuous emission spectrum ranging from the peak emission wavelength of the light-emitting element to 900 nm inclusive, where the maximum emission intensity within the range of the peak emission wavelength of the light-emitting element to 900 nm inclusive is 100%, and the minimum emission intensity within the range of the peak emission wavelength of the light-emitting element to 900 nm inclusive is 3% or more, can irradiate light from a light source having an emission spectrum ranging from visible light to part of the infrared range. Such a light-emitting device can be made more compact than light-emitting devices that use tungsten lamps or xenon lamps as light sources. Compact light-emitting devices can be installed in small mobile devices such as smartphones, and can obtain in vivo information, which can be used for health management, etc. Here, "within the range of the peak emission wavelength of the light-emitting element to 900 nm inclusive" refers to the range of 443 nm to 900 nm inclusive, for example, if the peak emission wavelength of the light-emitting element is 443 nm.

[0036] The light-emitting device has an emission spectrum that is continuous within a range of from the emission peak wavelength of the light-emitting element to 900 nm inclusive, with the maximum emission intensity within the range of from the emission peak wavelength of the light-emitting element to 900 nm inclusive being 100%, and the minimum emission intensity within the range of from the emission peak wavelength of the light-emitting element to 900 nm inclusive being 3% or more, and emits light over a wide wavelength range from visible light to near-infrared. Such a light-emitting device can be used, for example, in reflectance spectroscopic measuring devices and lighting devices that enable non-destructive measurement of living organisms, fruits and vegetables, etc., and that require light with excellent color rendering properties.

[0037] The second phosphor, which has a different composition from the first phosphor containing the oxide phosphor described above, preferably contains at least one phosphor selected from the group consisting of a phosphate phosphor having a composition falling within the composition formula represented by the following formula (2a), an aluminate phosphor having a composition falling within the composition formula represented by the following formula (2b), and an aluminate phosphor having a composition falling within the composition formula represented by the following formula (2c), and may contain two or more phosphors. (Ca, Sr, Ba, Mg) 10 (PO4)6(F,Cl,Br,I)2:Eu (2a) (Ba,Sr,Ca)MgAl10 O 17 :Eu (2b) Sr4Al 14 O 25 :Eu (2c) In this specification, in a composition formula, multiple elements separated by a comma (,) mean that at least one of these multiple elements is contained in the composition. Also, in this specification, in a composition formula representing the composition of a phosphor, the parts before the colon (:) represent the elements constituting the host crystal and their molar ratios, and the parts after the colon (:) represent an activator element.

[0038] The third phosphor preferably contains at least one phosphor selected from the group consisting of a silicate phosphor having a composition included in the composition formula represented by the following formula (3a), an aluminate phosphor or gallate phosphor having a composition included in the composition formula represented by the following formula (3b), a β-sialon phosphor having a composition included in the composition formula represented by the following formula (3c), a cesium lead halide phosphor having a composition included in the composition formula represented by the following formula (3d), and a nitride phosphor having a composition included in the composition formula represented by the following formula (3e), and may contain two or more phosphors. When the third phosphor contains two or more phosphors, it is preferable that each of the two or more third phosphors be a phosphor having a different emission peak wavelength in the range of 495 nm or more and less than 610 nm. (Ca,Sr,Ba)8MgSiO 16 (F,Cl,Br)2:Eu (3a) (Lu,Y,Gd,Tb)3(Al,Ga)5O 12 :Ce (3b) Si 6-z Al z O z N 8-z :Eu (0 <z≦4.2) (3c) CsPb(F,Cl,Br,I)3(3d) (La,Y,Gd)3Si6N 11 :Ce (3e)

[0039] The fourth phosphor preferably contains at least one phosphor selected from the group consisting of a nitride phosphor having a composition included in the compositional formula represented by the following formula (4a), a fluorogermanate phosphor having a composition included in the compositional formula represented by the following formula (4b), an oxynitride phosphor having a composition included in the compositional formula represented by the following formula (4c), a fluoride phosphor having a composition included in the compositional formula represented by the following formula (4d), a fluoride phosphor having a composition included in the compositional formula represented by the following formula (4e), a nitride phosphor having a composition included in the compositional formula represented by the following formula (4f), and a nitride phosphor having a composition included in the compositional formula represented by the following formula (4g), and may contain two or more phosphors. When the fourth phosphor contains two or more phosphors, it is preferable that each of the two or more fourth phosphors is a phosphor having an emission peak wavelength in a different range within the range of 610 nm or more and less than 700 nm. (Sr,Ca)AlSiN3:Eu (4a) 3.5MgO·0.5MgF2·GeO2:Mn (4b) (Ca,Sr,Mg) k Si 12-(m+n) Al m+n O n N 16-n :Eu (4c) (In the formula (4c), k, m, and n satisfy 0 < k ≤ 2.0, 2.0 ≤ m ≤ 6.0, and 0 ≤ n ≤ 2.0.) A c [M 4 1-b Mn 4+ b F d (4d) (In the formula (4d), A contains at least one selected from the group consisting of K + , Li + , Na + , Rb + , Cs + and NH4 + , and among them, K + is preferable. M 4 contains at least one element selected from the group consisting of a Group 4 element and a Group 14 element, and among them, Si and Ge are preferable. b satisfies 0 < b < 0.2, and c is [M4 1-b Mn 4+ b F d (The absolute value of the charge of the ion, and d satisfies 5 < d < 7.) A’ c’ [M 4 ’ 1-b’ Mn 4+ b’ F d’ (4e) (In formula (4e), A’ is K + , Li + , Na + , Rb + , Cs + and NH4 + selected from the group consisting of at least one, and among them, K + is preferred. M 4 ’ contains at least one element selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements, and among them, Si and Al are preferred. b’ satisfies 0 < b’ < 0.2, and c’ is the absolute value of the charge of the ion of [M 4 ’ 1-b’ Mn 4+ b’ F d’ (, and d’ satisfies 5 < d’ < 7.) (Ba,Sr,Ca)2Si5N8:Eu (4f) (Sr,Ca)LiAl3N4:Eu (4g)

[0040] It is preferable that the fifth phosphor contains at least one phosphor selected from the group consisting of a gallate phosphor having a composition formula represented by the following formula (5a), an aluminate phosphor having a composition formula represented by the following formula (5b), a gallate phosphor having a composition formula represented by the following formula (5c), and an aluminate phosphor having a composition contained in the composition formula represented by the following formula (5d), and a phosphor having a composition contained in the composition formula represented by the following formula (5e) different in composition from the above oxide phosphor, and it may contain two or more phosphors. For the phosphor having a composition contained in the composition formula represented by the following formula (5e), reference can be made to the disclosure of Japanese Patent Application No. 2020-198326. Ga2O3:Cr (5a) Al2O3:Cr (5b) ZnGa2O4:Cr (5c) (Lu,Y,Gd,Tb)3(Al,Ga)5O 12 :Ce,Cr (5d) M 5 g M 6 h M 7 i M 8 5O j :Cr e 、M 9 f (5e) (In the above formula (5e), M 5 is at least one element selected from the group consisting of Li, Na, K, Rb, and Cs, and M 6 is at least one element selected from the group consisting of Mg, Ca, Sr, Ba, and Zn, and M 7 is at least one element selected from the group consisting of Ba, Al, Ga, In, and rare earth elements, and M 8 is at least one element selected from the group consisting of Si, Ti, Ge, Zr, Sn, Hf, and Pb, and M 9 is at least one element selected from the group consisting of Eu, Ce, Tb, Pr, Nd, Sm, Yb, Ho, Er, Tm, Ni, and Mn, and e, f, g, h, i, and j satisfy 0 < e ≤ 0.2, 0 ≤ f ≤ 0.1, f < e, 0.7 ≤ g ≤ 1.3, 1.5 ≤ h ≤ 2.5, 0.7 ≤ i ≤ 1.3, 12.9 ≤ j ≤ 15.1.)

[0041] An example of a light-emitting device will be described based on the drawings. FIG. 1 is a schematic cross-sectional view showing an example of a first configuration example of the light-emitting device. FIG. 2 is a schematic cross-sectional view showing another example of the first configuration example of the light-emitting device.

[0042] As shown in FIG. 1, the light emitting device 100 includes a molded body 40 having a recess, a light emitting element 10 serving as a light source, and a wavelength conversion member 50 covering the light emitting element 10. The molded body 40 is formed by integrally molding a first lead 20, a second lead 30, and a resin portion 42 containing a thermoplastic resin or a thermosetting resin. The molded body 40 has the first lead 20 and the second lead 30 arranged to form the bottom surface of the recess, and the resin portion 42 arranged to form the side surface of the recess. The light emitting element 10 is placed on the bottom surface of the recess of the molded body 40. 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 via wires 60, respectively. The light emitting element 10 is covered with a wavelength conversion member 50. The wavelength conversion member 50 includes a phosphor 70 that converts the wavelength of the light emitting element 10 and a translucent material. The phosphor 70 essentially includes a first phosphor 71 containing an oxide phosphor. The phosphor 70 may contain a phosphor having an emission peak wavelength in a wavelength range different from the emission peak wavelength of the first phosphor 71. As shown in FIG. 2 , the phosphor 70 preferably contains at least one phosphor selected from the group consisting of the second phosphor 72, the third phosphor 73, the fourth phosphor 74, and the fifth phosphor 75, each of which is described above, and may contain two or more phosphors. The phosphor 70 essentially contains the first phosphor 71 and may also contain the second phosphor 72, the third phosphor 73, the fourth phosphor 74, and the fifth phosphor 75. The wavelength conversion member 50 also functions as a member for protecting the light emitting element 10 and the phosphor 70 from the external environment. The light emitting device 100 emits light upon receiving external power via the first lead 20 and the second lead 30.

[0043] 3A and 3B show a second configuration example of a light-emitting device. FIG. 3A is a schematic plan view of the light-emitting device 200. FIG. 3B is a schematic cross-sectional view of the light-emitting device 200 taken along line III-III' in FIG. 3A. The light-emitting device 200 includes a light-emitting element 10 having an emission peak wavelength in the range of 365 nm to 500 nm, and a wavelength conversion member 51 including a wavelength converter 52 containing a first phosphor 71 that emits light upon excitation with light from the light-emitting element 10 and a light-transmitting body 53 in which the wavelength converter 52 is disposed. The light-emitting element 10 is flip-chip mounted on the substrate 1 via bumps that are conductive members 61. The wavelength converter 52 of the wavelength conversion member 51 is provided on the light-emitting surface of the light-emitting element 10 via an adhesive layer 80. The light-emitting element 10 and the wavelength conversion member 52 have their side surfaces covered with a light-reflective covering member 90. The wavelength converter 52 is excited by light from the light-emitting element 10 and essentially contains a first phosphor 71 containing an oxide phosphor. The wavelength converter 52 may contain at least one selected from the group consisting of a second phosphor, a third phosphor, a fourth phosphor, and a fifth phosphor. The light emitting element 10 can receive power from outside the light emitting device 200 via wiring and a conductive member 61 formed on the substrate 1, causing the light emitting device 200 to emit light. The light emitting device 200 may also include a semiconductor element 11, such as a protective element, for protecting the light emitting element 10 from damage due to application of excessive voltage. The covering member 90 is provided so as to cover the semiconductor element 11, for example. Each member used in the light emitting device will be described below. For details, see, for example, the disclosure of JP 2014-112635 A.

[0044] The translucent material constituting the wavelength conversion member together with the phosphor may be at least one selected from the group consisting of resin, glass, and inorganic materials. The resin may be at least one selected from the group consisting of silicone resin, epoxy resin, phenolic resin, polycarbonate resin, acrylic resin, and modified resins thereof. Silicone resin and modified silicone resin are preferred because of their excellent heat resistance and light resistance. In addition to the phosphor and the translucent material, the wavelength conversion member may contain a filler, a colorant, and a light diffusing material as needed. Examples of fillers include silicon oxide, barium titanate, titanium oxide, and aluminum oxide.

[0045] When the wavelength conversion member contains a resin and a phosphor, it is preferable to form a composition for forming a wavelength conversion member containing the phosphor in the resin, and then form the wavelength conversion member using the composition for forming a wavelength conversion member. In the composition for forming a wavelength conversion member, the content of the first phosphor containing an oxide phosphor is preferably in the range of 20 parts by mass to 100 parts by mass, or alternatively, 25 parts by mass to 90 parts by mass, or alternatively, 30 parts by mass to 85 parts by mass, per 100 parts by mass of the resin. The first phosphor may contain only an oxide phosphor. The oxide phosphor contained in the first phosphor may contain two or more oxide phosphors with different compositions.

[0046] The composition for forming a wavelength conversion member is adjusted so that the content of each phosphor falls within the range described below. The content of the second phosphor contained in the composition for forming a wavelength conversion member may be in the range of 10 parts by mass or more and 100 parts by mass or less, 20 parts by mass or more and 90 parts by mass or less, or 30 parts by mass or more and 80 parts by mass or less, relative to 100 parts by mass of the resin. The content of the third phosphor contained in the composition for forming a wavelength conversion member may be in the range of 5 parts by mass or more and 100 parts by mass or less, 10 parts by mass or more and 90 parts by mass or less, 15 parts by mass or more and 80 parts by mass or less, 20 parts by mass or more and 70 parts by mass or less, or 25 parts by mass or more and 60 parts by mass or less, relative to 100 parts by mass of the resin. The content of the fourth phosphor contained in the composition for forming a wavelength conversion member may be in the range of 1 part by mass to 50 parts by mass or less, or in the range of 2 parts by mass to 40 parts by mass or less, or in the range of 3 parts by mass to 30 parts by mass or less, or in the range of 4 parts by mass to 40 parts by mass or less, or in the range of 5 parts by mass to 20 parts by mass or less, relative to 100 parts by mass of resin. The content of the fifth phosphor contained in the composition for forming a wavelength conversion member may be in the range of 5 parts by mass to 100 parts by mass, 10 parts by mass to 90 parts by mass, 10 parts by mass to 80 parts by mass, or 15 parts by mass to 70 parts by mass, relative to 100 parts by mass of the resin. When the composition for forming a wavelength conversion member contains a fifth phosphor and the fifth phosphor contains two or more types of phosphors, the content of the fifth phosphor refers to the total content of the two or more types of fifth phosphors. When the composition for forming a wavelength conversion member contains two or more types of phosphors, any of the second phosphor to the fourth phosphor, the content refers to the total content of the two or more types of phosphors. The total content of the phosphor contained in the composition for forming a wavelength conversion member may be in the range of 50 parts by mass or more and 300 parts by mass or less, or in the range of 100 parts by mass or more and 280 parts by mass or less, or in the range of 120 parts by mass or more and 250 parts by mass or less, or in the range of 150 parts by mass or more and 200 parts by mass or less, relative to 100 parts by mass of the resin.

[0047] The wavelength conversion member may include a light-transmitting body. The light-transmitting body can be a plate-shaped body made of a light-transmitting material such as glass or resin. Examples of glass include borosilicate glass and quartz glass. Examples of resin include silicone resin and epoxy resin. When the wavelength conversion member includes a substrate, the substrate is preferably made of an insulating material that is difficult to transmit light from the light-emitting element and external light. Examples of materials for the substrate include ceramics such as aluminum oxide and aluminum nitride, and resins such as phenolic resin, epoxy resin, polyimide resin, bismaleimide triazine resin (BT resin), and polyphthalamide (PPA) resin. When an adhesive layer is interposed between the light-emitting element and the wavelength conversion member, the adhesive constituting the adhesive layer is preferably made of a material that can optically connect the light-emitting element and the wavelength conversion member. The material constituting the adhesive layer is preferably at least one resin selected from the group consisting of epoxy resin, silicone resin, phenolic resin, and polyimide resin.

[0048] Examples of semiconductor elements that may be provided in a light-emitting device as needed include transistors for controlling light-emitting elements and protective elements for preventing damage to light-emitting elements or performance degradation due to excessive voltage application. Zener diodes are examples of protective elements. When a light-emitting device includes a covering member, an insulating material is preferably used as the material for the covering member. More specifically, examples include phenolic resin, epoxy resin, bismaleimide triazine resin (BT resin), polyphthalamide (PPA) resin, and silicone resin. Colorants, phosphors, and fillers may be added to the covering member as needed. The light-emitting device may use bumps as conductive members. Examples of materials for the bumps include Au or its alloys, and other conductive materials include eutectic solder (Au-Sn), Pb-Sn, and lead-free solder.

[0049] Light-emitting device manufacturing method An example of a method for manufacturing a light emitting device of the first configuration example will be described. For details, the disclosure of JP 2010-062272 A can be referenced, for example. The method for manufacturing a light emitting device preferably includes a molded body preparation step, a light emitting element arrangement step, a wavelength conversion member forming composition arrangement step, and a resin package formation step. When an aggregate molded body having a plurality of recesses is used as the molded body, the resin package formation step may be followed by a singulation step of separating the molded body into individual resin packages of each unit area.

[0050] In the step of preparing a molded body, a plurality of leads are integrally molded using a thermosetting resin or a thermoplastic resin to prepare a molded body having a recess with a side surface and a bottom surface. The molded body may be a molded body made of an aggregate base including a plurality of recesses. In the light-emitting element placement step, the light-emitting element is placed on the bottom surface of the recess of the molded body, and the positive and negative electrodes of the light-emitting element are connected to the first lead and the second lead by wires. In the step of placing the composition for forming a wavelength conversion member, the composition for forming a wavelength conversion member is placed in the recess of the molded body. In the resin package molding step, the wavelength conversion member-forming composition placed in the recesses of the molded body is cured to form a resin package, thereby manufacturing a light emitting device. When a molded body made of an aggregate substrate having multiple recesses is used, after the resin package formation step, the aggregate substrate having multiple recesses is separated into individual resin packages in each unit area in a singulation step, thereby manufacturing individual light emitting devices. In this manner, the light emitting device shown in FIG. 1 or 2 can be manufactured.

[0051] An example of a method for manufacturing the light emitting device of the second configuration example will be described. For details, reference can be made to the disclosures of, for example, Japanese Patent Application Laid-Open No. 2014-112635 or Japanese Patent Application Laid-Open No. 2017-117912. The method for manufacturing the light emitting device preferably includes a step of arranging a light emitting element, a step of arranging a semiconductor element as needed, a step of forming a wavelength conversion member including a wavelength converter, a step of bonding the light emitting element and the wavelength conversion member, and a step of forming a covering member.

[0052] For example, in the light-emitting element placement step, the light-emitting element is placed on a substrate. The light-emitting element and the semiconductor element are, for example, flip-chip mounted on the substrate. Next, in the wavelength conversion member formation step, the wavelength converter may be obtained by forming a plate-shaped, sheet-shaped, or layer-shaped wavelength converter on one surface of a translucent body using a printing method, an adhesive method, a compression molding method, or an electrodeposition method. For example, a printing method can be used to print a wavelength conversion member containing a phosphor and a resin serving as a binder or solvent on one surface of a translucent body to form a wavelength conversion member containing a wavelength converter. Next, in the bonding step between the light-emitting element and the wavelength conversion member, the wavelength conversion member is placed opposite the light-emitting surface of the light-emitting element and bonded to the light-emitting element with an adhesive layer. Next, in the coating member formation step, the side surfaces of the light-emitting element and the wavelength conversion member are covered with a coating member composition. This coating member is intended to reflect light emitted from the light-emitting element. If the light-emitting device also includes a semiconductor element, it is preferable to form the semiconductor element so that the coating member is embedded in the semiconductor element. In this manner, the light-emitting device shown in Figures 3A and 3B can be manufactured.

[0053] Method for producing oxide phosphor The method for producing an oxide phosphor includes mixing a first compound containing Mg, a second compound containing Ga, a third compound containing Cr, and, if necessary, at least one first element M selected from the group consisting of Ca, Sr, Ba, Ni, and Zn. 1 and a fourth compound containing at least one second element M selected from the group consisting of B, Al, In, and Sc. 2 and at least one third element M selected from the group consisting of Eu, Ce, Tb, Pr, Nd, Sm, Yb, Ho, Er, Tm, and Mn. 3 and preparing a sixth compound containing Ga, Cr, and a second element M in 1 mole of the oxide phosphor composition. 2 and the third element M 3 When the total molar ratio of Mg or the first element M is 2, 1 When it contains Mg and the first element M 1 The molar ratio of Mg and the first element M is in the range of 0.7 to 1.3, and the molar ratio of Cr is in the range of more than 0.02 to 0.3.1 The first element M when the total molar ratio of 1 The molar ratio of the second element M is in the range of 0 to 0.8. 2 The molar ratio of the third element M 3 The molar ratio of the third element M 3 preparing a raw material mixture by adjusting and mixing a first compound, a second compound, a third compound, and, if necessary, a fourth compound, a fifth compound, or a sixth compound so that the molar ratio of Cr is smaller than the molar ratio of Cr; and heat-treating the raw material mixture at a temperature in the range of 1200°C or higher and 1700°C or lower in an oxygen-containing atmosphere to obtain an oxide phosphor, wherein at least one compound selected from the group consisting of the first compound, the second compound, and the third compound is an oxide.

[0054] Raw material mixture preparation process raw material The raw materials for producing an oxide phosphor are a first compound containing Mg, a second compound containing Ga, a third compound containing Cr, and optionally a first element M. 1 A fourth compound containing a second element M 2 The fifth compound contains the third element M 3 The sixth compound containing the first element M may be an oxide, a carbonate, a chloride, or a hydrate thereof. At least one compound selected from the group consisting of the first compound, the second compound, and the third compound is an oxide, and two or more compounds may be oxides. The first element M may be optionally contained. 1 a third compound containing a second element M 2 A fifth compound containing a third element M 3 The sixth compound may be an oxide. The first compound, the second compound, the third compound, the fourth compound, the fifth compound and the sixth compound are preferably in the form of powder.

[0055] Specific examples of the first compound include MgO, MgCO3, MgCl2, and hydrates thereof. Specific examples of the second compound include Ga2O3, GaCl2, and GaCl3. Specific examples of the third compound include Cr2O3, Cr2(CO3)3, CrCl2, and CrCl3. The fourth, fifth, and sixth compounds are compounds containing the first element M. 1 , second element M 2 or the third element M 3 These include oxides containing , or compounds that are stable as compounds and easily turn into oxides. Examples include CaCO3, CaO, SrCO3, SrO, BaCO3, NiO, NiCO3, ZnO, B2O3, Al2O3, In2O3, Sc2O3, Eu2O3, Ce2O3, CeO2, Ce2(CO3)3, Tb4O7, and Pr7O. 11 , Pr(CO) , NdO, Nd(CO), SmO, Sm(CO), YbO, HoO, ErO, TmO, MnO, MnO, and MnO. The first, second, third, fourth, fifth, and sixth compounds may be hydrates.

[0056] raw material mixture Each compound used as a raw material is Ga, Cr, a second element M in 1 mole of the composition of the oxide phosphor to be obtained. 2 and the third element M 3 When the total molar ratio of Mg or the first element M is 2, 1 When it contains Mg and the first element M 1 The molar ratio of Mg and the first element M is in the range of 0.7 to 1.3, and the molar ratio of Cr is in the range of more than 0.02 to 0.3. 1 The first element M when the total molar ratio of 1 The molar ratio of the second element M is in the range of 0 to 0.8. 2 The molar ratio of the third element M 3 The molar ratio of the third element M 3a first compound containing Mg, a second compound containing Ga, a third compound containing Cr, and, if necessary, a first element M 1 and a fourth compound containing a second element M 2 and a fifth compound containing a third element M 3 and a sixth compound containing the compound are weighed out, and the compounds are mixed to obtain a raw material mixture. The weighed compounds may be mixed wet or dry, or may be mixed using a mixer. The mixer may be a ball mill, which is commonly used industrially, or a vibration mill, a roll mill, a jet mill, or the like.

[0057] Each compound used as a raw material contains Mg, Ga, and Cr, and optionally contains a first element M 1 , second element M 2 or the third element M 3 It is preferable to prepare a raw material mixture containing each compound weighed so that the composition falls within the composition formula represented by the formula (1).

[0058] Flux The raw material mixture may contain a flux. The inclusion of a flux in the raw material mixture further promotes the reaction between the raw materials and allows the solid-state reaction to proceed more uniformly, resulting in a phosphor with larger particle size and superior luminescence characteristics. When the heat treatment temperature for obtaining the phosphor is approximately the same as the temperature at which the liquid phase of the compound used as the flux is generated, the flux promotes the reaction between the raw materials. A halide containing at least one element selected from the group consisting of rare earth elements, alkaline earth metal elements, and alkali metal elements can be used as the flux. Among halides, fluoride can be used as the flux. When the elements contained in the flux are the same as at least some of the elements constituting the oxide phosphor, the flux can be added as part of the raw materials for the oxide phosphor having the desired composition so that the composition of the oxide phosphor becomes the desired composition. Alternatively, the flux can be added after the raw materials are mixed to obtain the desired composition.

[0059] A process for obtaining oxide phosphor by heat treatment The raw material mixture can be placed in a crucible or boat made of carbon such as graphite, boron nitride (BN), alumina (Al2O3), tungsten (W), molybdenum (Mo), or other materials, and heat-treated in a furnace.

[0060] Heat treatment atmosphere The heat treatment is preferably carried out in an oxygen-containing atmosphere. There are no particular restrictions on the oxygen content in the atmosphere. The oxygen content in the oxygen-containing atmosphere is preferably 5% by volume or more, more preferably 10% by volume or more, and even more preferably 15% by volume or more. The heat treatment is preferably carried out in an air atmosphere (oxygen content of 20% by volume or more). If the oxygen-free atmosphere has an oxygen content of less than 1% by volume, an oxide phosphor having the desired composition may not be obtained.

[0061] Heat Treatment Temperature The heat treatment temperature is within the range of 1200° C. to 1700° C., preferably 1250° C. to 1650° C., and more preferably 1300° C. to 1600° C. If the heat treatment temperature is 1200° C. to 1700° C., thermal decomposition is suppressed, and an oxide phosphor having the desired composition and a stable crystal structure can be obtained.

[0062] In the heat treatment, a holding time may be set at a predetermined temperature. The holding time may be, for example, 0.5 hours to 48 hours, 1 hour to 40 hours, or 2 hours to 30 hours. By setting the holding time to 0.5 hours to 48 hours, crystal growth can be promoted.

[0063] The pressure of the heat treatment atmosphere may be standard atmospheric pressure (0.101 MPa), or may be 0.101 MPa or higher, or may be a pressurized atmosphere in the range of 0.11 MPa to 200 MPa. The heat-treated product obtained by heat treatment is prone to decomposition of its crystalline structure when the heat treatment temperature is high, but decomposition of the crystalline structure can be suppressed when the heat treatment is performed in a pressurized atmosphere.

[0064] The heat treatment time can be appropriately selected depending on the heat treatment temperature and the pressure of the atmosphere during the heat treatment, and is preferably 0.5 to 20 hours. Even when two or more stages of heat treatment are performed, the heat treatment time for each stage is preferably 0.5 to 20 hours. If the heat treatment time is 0.5 to 20 hours, decomposition of the resulting heat-treated product is suppressed, and a phosphor with a stable crystal structure and desired emission intensity can be obtained. Furthermore, production costs can be reduced and the manufacturing time can be relatively shortened. The heat treatment time is more preferably 1 to 10 hours, and even more preferably 1.5 to 9 hours.

[0065] The heat-treated product obtained by the heat treatment may be subjected to post-treatments such as pulverization, dispersion, solid-liquid separation, drying, etc. Solid-liquid separation can be carried out by an industrially commonly used method such as filtration, suction filtration, pressure filtration, centrifugation, decantation, etc. Drying can be carried out by an industrially commonly used device such as a vacuum dryer, a hot air heating dryer, a conical dryer, a rotary evaporator, etc. [Example]

[0066] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0067] oxide phosphor Example 1 The raw materials were weighed out so that 8.44 g of MgCO3, 18.28 g of Ga2O3, and 0.38 g of Cr2O3 were used. The molar ratio of each element in 1 mole of the resulting oxide phosphor was MgGa 1.95 O4:Cr 0.05The raw materials were weighed out so that the total weight of the raw materials would be 100g. In the charged composition, the molar ratio of elements without a molar ratio specified is 1. The raw materials were mixed for 10 minutes using an agate mortar and agate pestle to obtain a raw material mixture. The obtained raw material mixture was placed in an alumina crucible and heat-treated for 6 hours in an air atmosphere (oxygen 20% by volume) at 1400°C and standard atmospheric pressure (0.101 MPa). After the heat treatment, the obtained heat-treated product was pulverized to obtain the oxide phosphor of Example 1.

[0068] Example 2 The raw materials were weighed so that MgCO3 was 8.44g, Ga2O3 was 18.09g, and Cr2O3 was 0.53g. The molar ratio of each element in the charged composition was MgGa 1.93 O4:Cr 0.07 An oxide phosphor of Example 2 was obtained in the same manner as in Example 1, except that a raw material mixture measured so as to satisfy the following formula was used.

[0069] Example 3 The raw materials were weighed so that 8.44 g of MgCO3, 17.91 g of Ga2O3, and 0.68 g of Cr2O3 were used. The molar ratio of each element in the charged composition was MgGa 1.91 O4:Cr 0.09 An oxide phosphor of Example 3 was obtained in the same manner as in Example 1, except that a raw material mixture measured so as to satisfy the following formula was used.

[0070] Example 4 The raw materials were weighed so that 8.44 g of MgCO3, 17.81 g of Ga2O3, and 0.76 g of Cr2O3 were used. The molar ratio of each element in the charged composition was MgGa 1.90 O4:Cr 0.10 An oxide phosphor of Example 4 was obtained in the same manner as in Example 1, except that a raw material mixture measured so as to satisfy the following formula was used.

[0071] Example 5 The raw materials were weighed so that 8.44 g of MgCO3, 18.47 g of Ga2O3, and 0.23 g of Cr2O3 were used. The molar ratio of each element in the charged composition was MgGa 1.97 O4:Cr 0.03An oxide phosphor of Example 5 was obtained in the same manner as in Example 1, except that a raw material mixture measured so as to satisfy the following formula was used.

[0072] Example 6 The raw materials were weighed so that MgCO3 was 8.44g, Ga2O3 was 17.34g, and Cr2O3 was 1.14g. The molar ratio of each element in the charged composition was MgGa 1.85 O4:Cr 0.15 An oxide phosphor of Example 6 was obtained in the same manner as in Example 1, except that a raw material mixture measured so as to satisfy the following formula was used.

[0073] Example 7 The raw materials were weighed so that 8.44 g of MgCO3, 16.87 g of Ga2O3, and 1.52 g of Cr2O3 were used. The molar ratio of each element in the charged composition was MgGa 1.80 O4:Cr 0.20 An oxide phosphor of Example 7 was obtained in the same manner as in Example 1, except that a raw material mixture measured so as to satisfy the following formula was used.

[0074] Example 8 The raw materials were weighed so that 8.44 g of MgCO3, 16.40 g of Ga2O3, and 1.90 g of Cr2O3 were used. The molar ratio of each element in the charged composition was MgGa 1.75 O4:Cr 0.25 An oxide phosphor of Example 8 was obtained in the same manner as in Example 1, except that a raw material mixture measured so as to satisfy the following formula was used.

[0075] Example 9 The raw materials were weighed so that 8.44 g of MgCO3, 15.94 g of Ga2O3, and 2.28 g of Cr2O3 were used. The molar ratio of each element in the charged composition was MgGa 1.70 O4:Cr 0.30 An oxide phosphor of Example 9 was obtained in the same manner as in Example 1, except that a raw material mixture measured so as to satisfy the following formula was used.

[0076] Example 10 The raw materials were weighed so that 8.44 g of MgCO3, 13.12 g of Ga2O3, 2.81 g of Al2O3, and 0.38 g of Cr2O3 were used. The molar ratio of each element in the charged composition was MgGa 1.40 Al 0.55 O4:Cr 0.05 In Example 10, when the charged composition is a composition represented by the formula (1), the second element M 2 is Al and the variable v is 0.275.

[0077] Example 11 The raw materials were weighed out so that 8.44g of MgCO3, 9.37g of Ga2O3, 4.85g of Al2O3, and 0.38g of Cr2O3 were used. The molar ratio of each element in the charged composition was MgGaAl 0.95 O4:Cr 0.05 In Example 11, when the charged composition is a composition represented by the formula (1), the second element M 2 is Al and the variable v is 0.475.

[0078] Example 12 The raw materials were weighed out so that 5.90 g of MgCO3, 2.44 g of ZnO, 17.91 g of Ga2O3, and 0.68 g of Cr2O3 were used. 0.7 Zn 0.3 Ga 1.91 O4:Cr 0.09 In Example 12, when the charged composition is a composition represented by the formula (1), the first element M 1 is Zn, the variable t is 0.3, and the variable u is 1.

[0079] Example 13 The raw materials were weighed out so that 4.22 g of MgCO3, 4.07 g of ZnO, 17.91 g of Ga2O3, and 0.68 g of Cr2O3 were used. 0.5 Zn 0.5 Ga 1.91 O4:Cr 0.09 In Example 13, when the charged composition is a composition represented by the formula (1), the first element M 1 is Zn, the variable t is 0.5, and the variable u is 1.

[0080] Example 14 The raw materials were weighed out so that 5.90g of MgCO3, 2.44g of ZnO, 9.37g of Ga2O3, 4.64g of Al2O3, and 0.68g of Cr2O3 were used. 0.7 Zn 0.3 GaAl 0.91 O4:Cr 0.09 In Example 14, when the charged composition is a composition represented by the formula (1), the first element M 1 is Zn, and the second element M 2 is Al, the variable t is 0.3, the variable u is 1, and the variable v is 0.455.

[0081] Example 15 The raw materials were weighed out so that 4.22 g of MgCO3, 4.07 g of ZnO, 9.37 g of Ga2O3, 4.64 g of Al2O3, and 0.68 g of Cr2O3 were used. 0.5 Zn 0.5 GaAl 0.91 O4:Cr 0.09 In Example 15, when the charged composition is a composition represented by the formula (1), the first element M 1is Zn, and the second element M 2 is Al, the variable t is 0.5, the variable u is 1, and the variable v is 0.455.

[0082] Comparative Example 1 The raw materials were weighed so that MgCO3 was 8.44g, Ga2O3 was 18.70g, and Cr2O3 was 0.04g. The molar ratio of each element in the charged composition was MgGa 1.995 O4:Cr 0.005 The oxide phosphor of Comparative Example 1 was obtained in the same manner as in Example 1, except that a raw material mixture weighed out so as to satisfy the following formula was used. The oxide phosphor of Comparative Example 1 had an emission spectrum measured by the measurement method described below, with an emission peak wavelength of 709 nm, which was shorter than 800 nm.

[0083] Comparative Example 2 The raw materials were weighed so that MgCO3 was 8.44g, Ga2O3 was 18.65g, and Cr2O3 was 0.08g. The molar ratio of each element in the charged composition was MgGa 1.99 O4:Cr 0.01 The oxide phosphor of Comparative Example 2 was obtained in the same manner as in Example 1, except that a raw material mixture weighed out so as to satisfy the following formula was used. The oxide phosphor of Comparative Example 2 had an emission spectrum measured by the measurement method described below, with an emission peak wavelength of 709 nm, which was shorter than 800 nm.

[0084] Comparative Example 3 The raw materials were weighed so that 8.14 g of ZnO, 18.56 g of Ga2O3, and 0.08 g of Cr2O3 were used. 1.99 O4:Cr 0.01 The oxide phosphor of Comparative Example 3 was obtained in the same manner as in Example 1, except that a raw material mixture weighed out so as to satisfy the following formula was used. The oxide phosphor of Comparative Example 3 had an emission spectrum measured by the measurement method described below, with an emission peak wavelength of 708 nm, which was shorter than 800 nm.

[0085] Comparative Example 4 The raw materials were weighed so that 8.14 g of ZnO, 18.37 g of Ga2O3, and 0.24 g of Cr2O3 were used. 1.97 O4:Cr 0.03 The oxide phosphor of Comparative Example 4 was obtained in the same manner as in Example 1, except that a raw material mixture weighed out so as to satisfy the following formula was used. The oxide phosphor of Comparative Example 4 had an emission spectrum measured by the measurement method described below, with an emission peak wavelength of 708 nm, which was shorter than 800 nm.

[0086] Measurement of central particle size (median diameter), emission spectrum, absorption spectrum and emission characteristics A laser diffraction particle size distribution analyzer (product name: MASTER SIZER3000, manufactured by MALVERN) was used to measure the central particle size (median diameter) Dm of the cumulative 50% particle size from the smallest diameter side in the volume-based particle size distribution of the oxide phosphor of Example 3. The central particle size Dm of the oxide phosphor of Example 3 was 12.8 μm. Figure 4 is a scanning electron microscope (SEM) photograph of the oxide phosphor of Example 3. The emission spectrum of each oxide phosphor of the Examples and Comparative Examples was measured using a quantum efficiency measurement system (QE-2000, manufactured by Otsuka Electronics Co., Ltd.). The emission peak wavelength of the excitation light used in the quantum efficiency measurement system was 450 nm. Furthermore, the absorption spectrum of the oxide phosphor of Example 3 was measured within a wavelength range of 200 nm to 700 nm using a quantum efficiency measurement system (QE-2000, manufactured by Otsuka Electronics Co., Ltd.). From the obtained emission spectrum of each phosphor, the relative emission intensity (%), emission peak wavelength (λp) (nm), and full width at half maximum (FWHM) (nm) were determined as emission characteristics. The relative emission intensity at the emission peak wavelength of the oxide phosphor of Example 9, which had the lowest emission intensity, was set to 100%, and the relative emission intensity at the emission peak wavelength of each oxide phosphor was determined. The results are shown in Table 1. Furthermore, FIG. 5 shows the emission spectra of the oxide phosphors of Examples 1 to 3. FIG. 6 shows the emission spectra of the oxide phosphors of Examples 4 to 6. FIG. 7 shows the emission spectra of the oxide phosphors according to Examples 7 to 9. FIG. 8 shows the emission spectra of the oxide phosphors according to Examples 10 to 12. FIG. 9 shows the emission spectra of the oxide phosphors according to Examples 13 to 15. FIG. 10 shows the absorption spectrum in the range of 300 nm to 700 nm of the oxide phosphor according to Example 3. In FIG. 10, the relative absorbance (%) in the range of 300 nm to 700 nm is shown, with the absorbance of the maximum absorption spectrum around 250 nm being 100%. FIG. 11 shows the emission spectra of the oxide phosphors according to Comparative Examples 1 and 2. FIG. 12 shows the emission spectra of the oxide phosphors according to Comparative Examples 3 and 4. In FIGS. 5 to 9 and 11 and 12, the emission spectra in the range of 400 nm to 500 nm are the emission spectra of excitation light.

[0087] [Table 1]

[0088] As shown in Table 1 or FIGS. 5 to 9, the oxide phosphors according to Examples 1 to 15 had emission peak wavelengths in the range of 800 nm to 1000 nm in their emission spectra, with full widths at half maximum (FWHM) of 150 nm or more. The oxide phosphors according to Examples 1 to 15 had emission peak wavelengths in the near-infrared wavelength range of 800 nm to 1000 nm in their emission spectra, with a wide full width at half maximum of 150 nm or more, more specifically, 200 nm or more. FIG. 10 shows the absorption spectrum of the oxide phosphor according to Example 3. It can be seen that there are peaks with relatively high absorptance in the range of 400 nm to 450 nm and in the range of 550 nm to 600 nm.

[0089] As shown in Table 1 or FIG. 11, the oxide phosphors according to Comparative Examples 1 and 2 have a molar ratio of Cr of less than 0.02 per mole of the oxide phosphor composition, and although the relative luminescence intensity is higher than that of, for example, the oxide phosphor according to Example 9, the peak emission wavelength is 709 nm, less than 800 nm. Furthermore, as shown in Table 1 or FIG. 12, the oxide phosphors according to Comparative Examples 3 and 4 have a peak emission wavelength of 708 nm, less than 800 nm, when irradiated with excitation light of 450 nm. The oxide phosphor according to Comparative Example 4 has a molar ratio of Cr of 0.02 or more per mole of the oxide phosphor composition, but does not contain Mg in the oxide phosphor composition, and the first element M, which is optionally contained in 1 mole of the oxide phosphor composition, is 1 Since the molar ratio of Zn exceeded 0.8, the emission peak wavelength was less than 800 nm.

[0090] Light emitting device according to the embodiment The wavelength conversion member used in the light emitting device was a phosphor expressed by the following composition and having the following emission peak wavelength when excited by a light emitting element with an emission peak wavelength of 450 nm. First phosphor Formula (1-1): MgGa 1.95 O4:Cr 0.05 , peak emission wavelength 890nm. Third phosphor Formula (3b-1): LuAlO 12: Ce, peak emission wavelength 520 nm. Fourth Phosphor Formula (4a-1): (Sr,Ca)AlSiN3:Eu, emission peak wavelength 620 nm. Formula (4a-2): CaAlSiN3:Eu, emission peak wavelength 660 nm. Fifth Phosphor Formula (5a): Ga2O3:Cr, emission peak wavelength 730 nm.

[0091] Light-emitting device of Example 1 The oxide phosphor of Example 1 was used as the first phosphor. The third, fourth, and fifth phosphors shown in Table 2 were mixed and dispersed with silicone resin to obtain the formulation shown in Table 2, and then degassed to obtain a composition for forming a wavelength conversion member. Table 2 shows the formulation of the first, third, fourth, and fifth phosphors per 100 parts by mass of resin in each Example and Comparative Example. The total amount of phosphor in the composition for forming a wavelength conversion member was 179.7 parts by mass per 100 parts by mass of resin. Next, a molded body having a recess as shown in FIG. 2 was prepared, and a light-emitting element having an emission peak wavelength of 443 nm and a gallium nitride-based compound semiconductor was placed on the bottom of the recess and attached to the first lead. The emission peak wavelength of the light-emitting element was 443 nm, and the full width at half maximum of the emission spectrum was 15 nm. After the light-emitting element was placed on the first lead, the composition for forming a wavelength conversion member was injected and filled on top of the light-emitting element, and further heated to harden the resin in the composition for forming a wavelength conversion member. The light emitting device of Example 1 does not include the second phosphor 72 in the wavelength conversion member shown in Fig. 2. The light emitting device according to the example was fabricated by the above steps.

[0092] Light-emitting device of Example 2 A composition for forming a wavelength conversion member was prepared so that the blending amounts of each of the first phosphor, third phosphor, fourth phosphor, and fifth phosphor per 100 parts by mass of resin were as shown in Table 2. Except for using this composition for forming a wavelength conversion member, the light emitting device of Example 2 and the light emitting device of Example 3 were manufactured in the same manner as the light emitting device of Example 1.

[0093] Measurement of emission spectrum The emission spectra of the light-emitting devices according to the examples were measured at room temperature (25°C ± 5°C) using an optical measurement system combining a spectrophotometer (PMA-11, Hamamatsu Photonics K.K.) and an integrating sphere. For each light-emitting device, the maximum emission intensity within the range of the emission peak wavelength of the light-emitting element and 900 nm inclusive in the emission spectrum of the light-emitting device was set to 100%, and the minimum relative emission intensity within the range of the emission peak wavelength of the light-emitting element and 900 nm inclusive was determined (minimum relative emission intensity (%) = minimum emission intensity / maximum emission intensity × 100). The results are shown in Table 2.

[0094] [Table 2]

[0095] The light emitting devices of Examples 1 and 2 emitted light in an emission spectrum in which the maximum value of the emission intensity in the range of 443 nm or more and 900 nm or less was 100%, and the minimum value of the emission intensity in the range of 443 nm or more and 1000 nm or less was 3% or more.

[0096] 13 is a diagram showing the emission spectra of the light emitting devices according to Examples 1 and 2. The emission spectra of the light emitting devices according to Examples 1 and 2 are continuous within a range from the emission peak wavelength of the light emitting element to 900 nm inclusive, and the maximum emission intensity within the range from the emission peak wavelength of the light emitting element to 900 nm inclusive is 100%, with the minimum emission intensity within the range from the emission peak wavelength of the light emitting element to 900 nm inclusive being 3% or more, and light having an emission spectrum within a wavelength range from visible light to part of infrared light can be emitted from the light source.

[0097] Example 16 The raw materials were weighed out so that 7.94 g of MgCO3, 0.45 g of NiO, 18.29 g of Ga2O3, and 0.38 g of Cr2O3 were used. The molar ratio of each element in 1 mole of the resulting oxide phosphor was Mg 0.94 Ni 0.06 Ga 1.95 O4:Cr0.05 The raw materials were mixed for 10 minutes using an agate mortar and an agate pestle to obtain a raw material mixture. The obtained raw material mixture was placed in an alumina crucible and heat-treated for 6 hours in an air atmosphere (oxygen 20% by volume) at 1400°C and standard atmospheric pressure (0.101 MPa). After the heat treatment, the obtained heat-treated product was pulverized to obtain the oxide phosphor of Example 16.

[0098] Example 17 The raw materials were weighed out so that 8.19 g of MgCO3, 0.23 g of NiO, 18.29 g of Ga2O3, and 0.38 g of Cr2O3 were used. The molar ratio of each element in 1 mole of the resulting oxide phosphor was Mg 0.97 Ni 0.03 Ga 1.95 O4:Cr 0.05 An oxide phosphor of Example 17 was obtained in the same manner as in Example 16, except that the weights were measured so that the total weight of the components was 100g.

[0099] Example 18 The raw materials were weighed out so that 8.19 g of MgCO3, 0.23 g of NiO, 17.91 g of Ga2O3, and 0.69 g of Cr2O3 were used. The molar ratio of each element in 1 mole of the resulting oxide phosphor was Mg 0.97 Ni 0.03 Ga 1.91 O4:Cr 0.09 An oxide phosphor of Example 18 was obtained in the same manner as in Example 16, except that the weights were measured so that the total weight of the components was 100g.

[0100] Example 19 The raw materials were weighed out so that 7.94 g of MgCO3, 0.45 g of NiO, 17.91 g of Ga2O3, and 0.69 g of Cr2O3 were used. The molar ratio of each element in 1 mole of the resulting oxide phosphor was Mg 0.94 Ni 0.06 Ga 1.91 O4:Cr 0.09 The oxide phosphor of Example 19 was obtained in the same manner as in Example 16, except that the weights were measured so that the total weight of the components was 1000 ppm or more.

[0101] Example 20 The raw materials were weighed out so that 7.60 g of MgCO3, 0.75 g of NiO, 17.91 g of Ga2O3, and 0.69 g of Cr2O3 were used. The molar ratio of each element in 1 mole of the resulting oxide phosphor was Mg 0.90 Ni 0.10 Ga 1.91 O4:Cr 0.09 The oxide phosphor of Example 20 was obtained in the same manner as in Example 16, except that the weights were measured so that the total weight of the components was 100g.

[0102] Example 21 The raw materials were weighed out so that 8.19 g of MgCO3, 0.23 g of NiO, 18.47 g of Ga2O3, and 0.23 g of Cr2O3 were used. The molar ratio of each element in 1 mole of the resulting oxide phosphor was Mg 0.97 Ni 0.03 Ga 1.97 O4:Cr 0.03 An oxide phosphor of Example 21 was obtained in the same manner as in Example 16, except that the weights were measured so that the total weight of the components was 1000 ppm or more.

[0103] Example 22 The raw materials were weighed out so that 8.32 g of MgCO3, 0.12 g of NiO, 17.91 g of Ga2O3, and 0.69 g of Cr2O3 were used. The molar ratio of each element in 1 mole of the resulting oxide phosphor was Mg 0.985 Ni 0.015 Ga 1.91 O4:Cr 0.09 An oxide phosphor of Example 22 was obtained in the same manner as in Example 16, except that the weights were measured so that the total weight of the components was 100g.

[0104] Example 23 The raw materials were weighed out so that 8.25 g of MgCO3, 0.18 g of NiO, 17.91 g of Ga2O3, and 0.69 g of Cr2O3 were used. The molar ratio of each element in 1 mole of the resulting oxide phosphor was Mg 0.977 Ni 0.023 Ga 1.91 O4:Cr 0.09An oxide phosphor of Example 23 was obtained in the same manner as in Example 16, except that the weights were measured so that the total weight of the components was 100g.

[0105] Example 24 The raw materials were weighed out so that 8.39 g of MgCO3, 0.05 g of NiO, 17.91 g of Ga2O3, and 0.69 g of Cr2O3 were used. The molar ratio of each element in 1 mole of the resulting oxide phosphor was Mg 0.993 Ni 0.007 Ga 1.91 O4:Cr 0.09 The oxide phosphor of Example 24 was obtained in the same manner as in Example 16, except that the weights were measured so that the total weight of the components was 100g.

[0106] Measurement of luminescence properties The emission spectra of each oxide of the obtained examples were measured using a quantum efficiency measurement system (QE-2000, manufactured by Otsuka Electronics Co., Ltd.) using the same method as the above-mentioned method for measuring emission characteristics. The emission peak wavelength of the excitation light used in the quantum efficiency measurement system was 450 nm. From the emission spectrum of each obtained phosphor, the relative emission intensity (%), emission peak wavelength (λp) (nm), and full width at half maximum (FWHM) (nm) were determined as emission characteristics. The relative emission intensity at the emission peak wavelength of the oxide phosphor of Example 16, which had the lowest emission intensity among the oxide phosphors of Examples 16 to 24, was set to 100%, and the relative emission intensity at the emission peak wavelength of each oxide phosphor was calculated. The results are shown in Table 3. Furthermore, FIG. 5 shows the emission spectra of the oxide phosphors of Examples 1 to 3 in the range of 1000 nm to 1600 nm. FIG. 14 shows the emission spectra of the oxide phosphors of Examples 16 to 18 in the range of 100 nm to 1600 nm. Fig. 15 shows the emission spectra of the oxide phosphors according to Examples 19 to 21. Fig. 16 shows the emission spectra of the oxide phosphors according to Examples 22 to 24 within the range of 1000 nm to 1600 nm.

[0107] [Table 3]

[0108] 14 to 16, the oxide phosphors according to Examples 16 to 24 had emission peak wavelengths in the range of 800 nm to 1600 nm, more specifically, in the range of 1001 nm to 1600 nm, and full widths at half maximum (FWHM) of 150 nm or more in the emission spectrum. The oxide phosphors according to Examples 1 to 15 had emission peak wavelengths in the near-infrared wavelength range of 800 nm to 1600 nm, and had emission spectra with wide full widths at half maximum of 150 nm or more, more specifically, 330 nm or less. [Industrial Applicability]

[0109] The oxide phosphor according to the present disclosure can also be used in a medical light-emitting device for obtaining information inside a living body, a light-emitting device that is mounted on a small mobile device such as a smartphone to manage health conditions, a light-emitting device for an analytical device that non-destructively measures internal information about food such as fruits and vegetables and rice, and a light-emitting device for a reflectance spectroscopic measuring device used to measure film thickness, etc. [Explanation of symbols]

[0110] 10: light-emitting element, 11: semiconductor element, 20: first lead, 30: second lead, 40: molded body, 42: resin part, 50, 51: wavelength conversion member, 52: wavelength conversion member, 53: light-transmitting body, 60: wire, 61: conductive member, 70: phosphor, 71: first phosphor, 72: second phosphor, 73: third phosphor, 74: fourth phosphor, 75: fifth phosphor, 80: adhesive layer, 90: covering member, 100, 200: light-emitting device.

Claims

1. Contains Mg, Ga, O (oxygen), and Cr, If necessary, at least one first element M selected from the group consisting of Ca, Sr, Ba, Ni and Zn １ and at least one second element M selected from the group consisting of B, Al, In, and Sc. ２ and at least one third element M selected from the group consisting of Eu, Ce, Tb, Pr, Nd, Sm, Yb, Ho, Er, Tm, and Mn. ３ and an oxide phosphor having a composition which may include The Ga, the Cr, and the second element M in 1 mol of the oxide phosphor composition ２ and the third element M ３ When the total molar ratio of Mg and the first element M is 2, １ When the compound contains Mg, the compound contains the first element M １ The total molar ratio of is in the range of 0.7 or more and 1.3 or less, the molar ratio of O is in the range of 3.7 or more and 4.3 or less, the Cr molar ratio is in the range of more than 0.02 and not more than 0.3, Furthermore, the Mg and the first element M １ The molar ratio of the first element M when the total of １ is in the range of 0 to 0.8, The second element M ２ The molar ratio of the third element M is in the range of 0 to 1.

6. ３ is in the range of 0 to 0.2, and the molar ratio of the third element M ３ an oxide phosphor having an emission spectrum having an emission peak wavelength in the range of 800 nm to 1600 nm inclusive, wherein the molar ratio of

2. 2. The oxide phosphor according to claim 1, having a composition included in a composition formula represented by the following formula (1): (Mg １－ｔ M １ ｔ ) ｕ (Ga １－ｖ－ｘ－ｙ M ２ ｖ ) ２ O ｗ :Cr ｘ ,M ３ ｙ (1) (In the formula (1), t, u, v, w, x, and y satisfy the following conditions: 0≦t≦0.8, 0.7≦u≦1.3, 0≦v≦0.8, 3.7≦w≦4.3, 0.02<x≦0.3, 0≦y≦0.2, y<x.)

3. The first element M １ is at least one element selected from the group consisting of Ca, Sr, Ni and Zn, and the second element M ２ is at least one element selected from the group consisting of Al and Sc, and the third element M ３ 3. The oxide phosphor according to claim 1, wherein is at least one element selected from the group consisting of Eu, Ce, and Mn.

4. The first element M １ is Ni, and the Mg and the first element M １ When the total molar ratio of the first element M １ 2. The oxide phosphor according to claim 1, wherein the molar ratio of is in the range of 0.001 to 0.

50.

5. The first element M １ The oxide phosphor according to claim 2 , wherein is Ni, and in formula (1), t satisfies 0.001≦t≦0.

50.

6. 6. The oxide phosphor according to claim 1, wherein the full width at half maximum of an emission spectrum having the emission peak wavelength of the oxide phosphor is 150 nm or more.

7. A light emitting device comprising: the oxide phosphor according to claim 1 ; and a light emitting element having an emission peak wavelength in the range of 365 nm to 500 nm, which irradiates the oxide phosphor.

8. a first phosphor containing the oxide phosphor is essential, a light emitting device comprising at least one phosphor selected from the group consisting of a second phosphor having an emission peak wavelength in the range of 455 nm or more and less than 495 nm, a third phosphor having an emission peak wavelength in the range of 495 nm or more and less than 610 nm, a fourth phosphor having an emission peak wavelength in the range of 610 nm or more and less than 700 nm, and a fifth phosphor having an emission peak wavelength in the range of 700 nm or more and 1050 nm, in the emission spectra of the respective phosphors; 8. The light emitting device according to claim 7, wherein the light emitting device has an emission spectrum in which the maximum value of the emission intensity within a range of the emission peak wavelength of the light emitting element and 900 nm inclusive is 100%, and the minimum value of the emission intensity within a range of the emission peak wavelength of the light emitting element and 900 nm inclusive is 3% or more.

9. 9. The light emitting device according to claim 8, wherein the second phosphor comprises at least one phosphor selected from the group consisting of a phosphate phosphor having a composition included in the composition formula represented by the following formula (2a), an aluminate phosphor having a composition included in the composition formula represented by the following formula (2b), and an aluminate phosphor having a composition included in the composition formula represented by the following formula (2c): (Ca,Sr,Ba,Mg) １０ (PO ４ ) ６ (F,Cl,Br,I) ２ :Eu (2a) (Ba,Sr,Ca)MgAl １０ O １７ :Eu(2b) Mr. ４ Al １４ O ２５ :Eu(2c)

10. 10. The light emitting device according to claim 8 or 9, wherein the third phosphor comprises at least one phosphor selected from the group consisting of a silicate phosphor having a composition included in the composition formula represented by the following formula (3a), an aluminate phosphor or gallate phosphor having a composition included in the composition formula represented by the following formula (3b), a β-sialon phosphor having a composition included in the composition formula represented by the following formula (3c), a cesium lead halide phosphor having a composition included in the composition formula represented by the following formula (3d), and a nitride phosphor having a composition included in the composition formula represented by the following formula (3e): (1,Sr,BL) ８ Yes ４ O １６ (F, Cl, Br) ２ :Eu (3a) (Lu,Y,Gd,Tb) ３ (A-,1) ５ O １２ :Ce (3ｬ) Yes ６－ｚ Al ｚ O ｚ N ８－ｚ :Eu (0<z≦4.2) (3c) CsPb(F,Cl,Br) ３ (3d) (L, Y, G) ３ Yes ６ N １１ :Ce (3e)

11. 11. The light emitting device according to claim 8, wherein the fourth phosphor comprises at least one phosphor selected from the group consisting of a nitride phosphor having a composition included in the composition formula represented by the following formula (4a), a fluorogermanate phosphor having a composition included in the composition formula represented by the following formula (4b), an oxynitride phosphor having a composition included in the composition formula represented by the following formula (4c), a fluoride phosphor having a composition included in the composition formula represented by the following formula (4d), a fluoride phosphor having a composition included in the composition formula represented by the following formula (4e), a nitride phosphor having a composition represented by the following formula (4f), and a nitride phosphor having a composition represented by the following formula (4g). (Sr,Ca)AlSiN ３ :Eu (4a) 359・059 ２ ・N2 ２ NO (4) (Ca,Sr,Mg) ｋ Yes １２－（ｍ＋ｎ） Al ｍ＋ｎ O ｎ N １６－ｎ :Eu (4c) (In the formula (4c), k, m, and n satisfy the following conditions: 0<k≦2.0, 2.0≦m≦6.0, and 0≦n≦2.0.) A ｃ [M ４ １－ｂ Mn ４＋ ｂ F ｄ ] (4d) (In the formula (4d), A is K ＋ , Li ＋ , Na ＋ , Rb ＋ , Cs ＋ and N.H. ４ ＋ and M ４ contains at least one element selected from the group consisting of Group 4 elements and Group 14 elements, b satisfies 0<b<0.2, and c satisfies [M ４ １－ｂ Mn ４＋ ｂ F ｄ ] is the absolute value of the charge of the ion, and d satisfies the relationship 5<d<7. A' ｃ’ [M ４ ' １－ｂ’ Mn ４＋ ｂ’ F ｄ’ ] (4e) (In formula (4e), A' is K ＋ , Li ＋ , Na ＋ , Rb ＋ , Cs ＋ and N.H. ４ ＋ and M ４ b′ contains at least one element selected from the group consisting of Group 4 elements, Group 13 elements, and Group 14 elements, b′ satisfies 0<b′<0.2, and c′ satisfies [M ２ ' １－ｂ’ Mn ４＋ ｂ’ F ｄ’ ] is the absolute value of the charge of the ion, and d' satisfies the relationship 5<d'<7. (Ba,Sr,Ca) ２ Si ５ N ８ :Eu (4f) (Sr,Ca)LiAl ３ N ４ :Eu(4g)

12. 12. The light emitting device according to claim 8, wherein the fifth phosphor comprises at least one phosphor selected from the group consisting of a gallate phosphor having a composition represented by the following formula (5a), an aluminate phosphor having a composition represented by the following formula (5b), a gallate phosphor having a composition represented by the following formula (5c), an aluminate phosphor having a composition represented by the following formula (5d), and a phosphor having a composition included in a composition formula represented by the following formula (5e): Ga ２ O ３ :Cr (5a) Al ２ O ３ :Cr (5b) Zinc ２ O ４ :Cr (5c) (Lu,Y,Gd,Tb) ３ (A-,1) ５ O １２ :Ce,Cr (5d) M ５ ｇ M ６ ｈ M ７ ｉ M ８ ５ O ｊ :Cr ｅ 、M ９ ｆ (5e) (In the formula (5e), ​​M ５ is at least one element selected from the group consisting of Li, Na, Ka, Rb, and Cs, and M ６ is at least one element selected from the group consisting of Mg, Ca, Sr, Ba, and Zn, and M ７ is at least one element selected from the group consisting of Ba, Al, Ga, In and rare earth elements, and M ８ is at least one element selected from the group consisting of Si, Ti, Ge, Zr, Sn, Hf and Pb, and M ９ is at least one element selected from the group consisting of Eu, Ce, Tb, Pr, Nd, Sm, Yb, Ho, Er, Tm, Ni, and Mn, and e, f, g, h, i, and j satisfy 0<e≦0.2, 0≦f≦0.1, f<e, 0.7≦g≦1.3, 1.5≦h≦2.5, 0.7≦i≦1.3, 12.9≦j≦15.

1.

13. A first compound containing Mg, a second compound containing Ga, a third compound containing Cr, and optionally at least one first element M selected from the group consisting of Ca, Sr, Ba, Ni, and Zn. １ and at least one second element M selected from the group consisting of B, Al, In, and Sc. ２ and at least one third element M selected from the group consisting of Eu, Ce, Tb, Pr, Nd, Sm, Yb, Ho, Er, Tm, and Mn. ３ and a sixth compound comprising: The composition of the oxide phosphor is Ga, Cr, the second element M, ２ and the third element M ３ When the total molar ratio of Mg or the first element M is 2, １ When Mg and the first element M １ The molar ratio of Mg and the first element M is in the range of 0.7 to 1.3, and the molar ratio of Cr is in the range of more than 0.02 to 0.

3. １ The molar ratio of the first element M when the total of １ The molar ratio of the second element M ２ The molar ratio of the third element M ３ The molar ratio of the third element M ３ preparing a raw material mixture by adjusting and mixing the first compound, the second compound, the third compound, and, if necessary, the fourth compound, the fifth compound, or the sixth compound so that the molar ratio of heat-treating the raw material mixture in an oxygen-containing atmosphere at a temperature in the range of 1200°C to 1700°C to obtain an oxide phosphor; The method for producing an oxide phosphor, wherein at least one compound selected from the group consisting of the first compound, the second compound, and the third compound is an oxide.

14. The method for producing an oxide phosphor according to claim 13 , wherein the raw material mixture is prepared so as to have a composition included in a composition formula represented by the following formula (1): (Mg １－ｔ M １ ｔ ) ｕ (Ga １－ｖ－ｘ－ｙ M ２ ｖ ) ２ O ｗ :Cr ｘ ,M ３ ｙ (1) (In the formula (1), t, u, v, w, x, and y satisfy the following conditions: 0≦t≦0.8, 0.7≦u≦1.3, 0≦v≦0.8, 3.7≦w≦4.3, 0.02<x≦0.3, 0≦y≦0.2, y<x.)

15. The method for producing an oxide phosphor according to claim 13 or 14, wherein the heat treatment is carried out in an air atmosphere.

16. The method for producing an oxide phosphor according to claim 13 , wherein the temperature of the heat treatment is in the range of 1300° C. or more and 1600° C. or less.

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