JP2018109076A - Green phosphor, light emitting element and light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a γ-AlON green phosphor having improved brightness, a light emitting element including the phosphor, and a light emitting device including the light emitting element.SOLUTION: A green phosphor has a host crystal having the same crystal structure as a cubic spinel AlON crystal, and in the host crystal, element M (where element M is at least one element selected from Mn, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Tm, Yb) and element A (where element A is at least one metal element other than element M and Al) are dissolved in a solid state, where an aspect ratio obtained by dividing a minor axis of each phosphor particle by its major axis is 0.7 or more on average.SELECTED DRAWING: None

Description

The present invention relates to a green phosphor, and a light emitting element and a light emitting device using the phosphor. More specifically, the present invention relates to a green phosphor that is excellent in luminance and can be preferably used for an LED (also referred to as a light emitting diode) or an LD (also referred to as a laser diode), and a light emitting element and a light emitting device using the phosphor.

A white LED is a device that emits pseudo white light by a combination of a semiconductor light-emitting element and a phosphor. As a typical example, a combination of a blue LED and a YAG yellow phosphor is known. However, although this type of white LED is in the white region as its chromaticity coordinate value, it lacks the green light emission component and the red light emission component, so it has a low color rendering property for lighting applications, and is similar to a liquid crystal backlight. Such an image display device has a problem that color reproducibility is poor. Therefore, in order to compensate for the lack of light emitting components, a light emitting device combining a blue LED, a green phosphor and a red phosphor has been proposed. As a typical example of a phosphor emitting green light, a β sialon phosphor in which silicon nitride silicon, a part of nitrogen is aluminum, and β sialon in which oxygen is substituted to form a solid solution and an element serving as a luminescent center is further dissolved is known. It has been.

As other phosphors emitting green light, Patent Documents 1 and 2 disclose that an inorganic crystal having the same crystal structure as a cubic spinel AlON crystal (also referred to as γ-AlON) is a base crystal, for example, Mn A phosphor in which a combination of elements such as Mg or a combination of elements such as Mn, Eu and Mg, or Mn and Si is further dissolved in the base crystal (hereinafter also referred to as a γ-AlON phosphor) is disclosed. In principle, γ-AlON phosphors have a narrow emission spectrum half-width, and the emission peak wavelength of green phosphors is on the shorter wavelength side than the emission peak wavelength of β sialon phosphors. A light emitting device with higher efficiency and wider color reproducibility can be obtained. Patent Documents 3 and 4 also propose a light emitting device that combines a γ-AlON phosphor, a red phosphor, and a light source.

However, although γ-AlON phosphors are more advantageous than β sialon phosphors in terms of emission wavelength, the luminance is somewhat insufficient for use as a light emitting device, and there is room for improvement in this respect. It was. For this reason, in the industry, it has been expected to increase the luminance of the γ-AlON phosphor so that a light emitting element and a light emitting device having high luminance can be provided.

International Publication No. 2007/099862 Pamphlet JP 2009-096854 A JP 2009-218422 A JP 2010-093132 A

An object of the present invention is to provide a γ-AlON green phosphor having higher luminance, a light emitting element including the phosphor, and a light emitting device using the light emitting element.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have obtained a γ-AlON green phosphor in which a plurality of elements are further dissolved in a base crystal having the same crystal structure as a cubic spinel AlON crystal. And γ-AlON green phosphors with higher phosphor brightness can be obtained by defining the range of the average aspect ratio obtained by dividing the minor axis of the phosphor particles by the major axis. It came to do.

That is, the present invention
(1) To a base crystal having the same crystal structure as that of a cubic spinel AlON crystal, an element M (wherein the element M is Mn, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Tm, Yb) A green phosphor in which element A (one or more selected elements) and element A (where element A is one or more metal elements other than element M and Al) are in solid solution; A green phosphor having an average aspect ratio of 0.7 or more obtained by dividing by the major axis.
(2) The green phosphor described in (1) is preferably a phosphor in which the proportion of particles having an aspect ratio value of 0.7 or more is 50% or more of the whole particles on a number basis.
(3) The phosphor according to (1) or (2) is a green phosphor in which the ratio of particles having a circularity value of 0.6 or more is 50% or more of the total number of particles on a number basis. preferable.
(4) The green phosphor according to any one of (1) to (3) has a composition formula of MaAbAlcOdNe (where M is element M, A is element A, Al is aluminum, O is oxygen, and N is nitrogen) And satisfies a + b + c + d + e = 1) and is preferably a green phosphor of 0.00001 ≦ a ≦ 0.1.
(5) The green phosphor according to any one of (1) to (4) has a composition formula of MaAbAlcOdNe (where M is element M, A is element A, Al is aluminum, O is oxygen, and N is nitrogen) And satisfies a + b + c + d + e = 1), and is preferably a green phosphor with 0.001 ≦ b ≦ 0.40.
(6) In the green phosphor according to any one of (1) to (5), the element M is preferably Mn.
(7) In the green phosphor according to any one of (1) to (6), the element A preferably contains at least Mg.
(8) Moreover, this invention is a light emitting element containing the green fluorescent substance as described in any one of said (1)-(7).
(9) Moreover, this invention is a light-emitting device using the light emitting element of said (8) description.

By implementing the present invention, it is possible to obtain a green phosphor with higher brightness than conventional ones, such as a blue LED that can excite the phosphor of the present invention, and the green phosphor of the present invention and, if necessary, another color. For example, it is possible to provide a light emitting element such as a white LED including a phosphor that emits light in combination (for example, a red phosphor), and a light emitting device using these light emitting elements. Examples of the light emitting device include a lighting device, a backlight device, an image display device, and a signal device.

Hereinafter, embodiments for carrying out the present invention will be described in detail.

By implementing the present invention, a base crystal having the same crystal structure as that of the cubic spinel AlON crystal is converted into an element M (where the element M is Mn, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Tm, A green phosphor in which one or more elements selected from Yb) and element A (wherein element A is one or more metal elements other than element M and Al) is obtained as a solid solution is obtained. More specifically, the base crystal having the same crystal structure as the cubic spinel type AlON crystal in the present invention includes a cubic spinel type AlON crystal, an AlON solid solution crystal, the AlON crystal, and the AlON solid solution crystal. It is a general term for crystals having the same crystal structure as the cubic spinel AlON crystal. The cubic spinel AlON crystal is more generally called γ-AlON. The AlON solid solution crystal is a crystal having the same crystal structure as that of the AlON but having an oxygen / nitrogen ratio different from that of the AlON or having other elements such as silicon and Mn added thereto. Furthermore, the crystal having the same crystal structure as the cubic spinel type AlON crystal is a crystal having the same crystal structure as that of the AlON, except that some or all of Al, O, and N are replaced with other elements. Among these, γ-AlON is the most typical crystal.

In this specification, for convenience, it is described that the main crystal structure of the phosphor is represented by, for example, γ-AlON. However, even if the raw materials are blended so as to obtain a phosphor having such a composition, impurities in the raw materials and firing The composition of the phosphor may fluctuate due to the influence of the atmosphere at the time. The composition of the green phosphor of the present invention is an expression including such a variation.

Whether or not the base crystal of the green phosphor of the present invention has the same crystal structure as γ-AlON can be confirmed by powder X-ray diffraction measurement. When the host crystal of the phosphor of the present invention does not have the same crystal structure as that of γ-AlON, the emission color is not green, and the fluorescence intensity is greatly reduced, which is not preferable. In the green phosphor of the present invention, the base crystal having the same crystal structure as that of γ-AlON is preferably a single-phase crystal, but contains a heterophasic crystal as long as the phosphor characteristics are not greatly affected. It doesn't matter. Presence / absence of heterogeneous crystals can also be determined by the presence / absence of peaks other than those due to the target crystal phase by powder X-ray diffraction measurement. In addition, elements in which the lattice constant is changed by partially replacing the constituent elements of γ-AlON with other elements are also included in the present invention.

The green phosphor of the present invention is obtained by adding Mn, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Tm to a base crystal having the same crystal structure as a cubic spinel AlON (ie, γ-AlON) crystal. , Yb is a phosphor in which one or more elements M selected from Yb are dissolved. The element M is an element that becomes the emission center of the phosphor, and Mn is particularly preferable in the green phosphor of the present invention.

The green phosphor of the present invention is a phosphor in which the element A is further dissolved in addition to the element M. The element A is one or more metal elements other than the elements M and Al, and preferably contains Mg.

In the green phosphor of the present invention, the average aspect ratio obtained by dividing the minor axis of the phosphor particle by the major axis is 0.7 or more. If the average value of the aspect ratio is less than 0.7, the luminance of the light emitting device using this phosphor is lowered. When the ratio of the number is measured, it is not necessary to actually measure all the phosphor particles, and a value obtained by sampling a part may be used. However, in the present invention, at least 100 phosphor particles are sampled and the aspect ratio value is measured. This is also true other than measuring the aspect ratio value.

In the green phosphor of the present invention, the proportion of particles having an aspect ratio value of 0.7 or more is preferably 50% or more of the total number of particles on a number basis. If it is less than 50%, the luminance of the light emitting device using this phosphor tends to be lowered.

In the green phosphor of the present invention, the proportion of particles having a circularity of 0.6 or more of the phosphor is preferably 50% or more of the whole particles on a number basis. If it is less than 50%, the luminance of the light emitting device using this phosphor tends to be lowered.

The composition of the green phosphor of the present invention is expressed by MaAbAlcOdNe (where M is element M, A is element A, Al is aluminum, O is oxygen, N is nitrogen, and a + b + c + d + e = 1 is satisfied). It is preferable that 0.00001 ≦ a ≦ 0.1. If a is smaller than 0.00001, the luminance decreases because the number of elements M that are the emission centers is small. On the other hand, when a is larger than 0.1, the luminance is lowered by an interference phenomenon between elements M called concentration quenching.

The green phosphor of the present invention preferably satisfies 0.001 ≦ b ≦ 0.40 in the composition formula of the present invention. If b is out of this range, the host crystal of the phosphor becomes chemically unstable, and the ratio of the crystal phase other than the crystal phase represented by γ-AlON (that is, a different phase) increases, so that the luminance decreases.

The production method of the green phosphor of the present invention can be the same production method as the conventional production method of γ-AlON phosphor. Here, as a method for obtaining a crystal in which the element M and the element A are dissolved in the γ-AlON crystal according to one embodiment of the present invention, a powder in which raw materials that can constitute the crystal are mixed in a nitrogen atmosphere. Although the method of baking in a predetermined temperature range is illustrated, it does not specifically limit to this method.

The above-mentioned manufacturing method prepares a simple substance and / or a compound containing element M, element A, aluminum, oxygen, and nitrogen as a raw material of the green phosphor of the present invention, and a compound that can obtain a target phosphor In the manufacturing method including the preparation step of mixing the raw materials and the baking step of baking the raw material to obtain the green phosphor of the present invention. The simple substance or compound containing the element M is a metal containing the element M, an oxide, carbonate, nitride, fluoride, chloride, oxynitride of the element M, or a combination thereof. The simple substance or compound containing the element A is a metal containing the element A, an oxide of the element A, carbonate, nitride, fluoride, chloride, oxynitride, or a combination thereof. Further, the simple substance or compound containing aluminum is aluminum, an aluminum alloy, aluminum oxide, aluminum nitride, or a combination thereof. Oxygen and nitrogen, which are raw materials for the green phosphor of the present invention, can be supplied from the oxides and nitrides, and the atmospheric gas (nitrogen gas) in the furnace for sintering. Each of these raw materials is preferably in the form of a powder if it is solid, and is preferably mixed in advance before firing.

The raw material uniformly mixed in advance (hereinafter referred to as raw material mixed powder) is filled in a firing container and fired. The firing container is preferably made of a material that is sufficiently chemically and physically (mechanically) stable at least in a nitrogen atmosphere at the firing temperature and is difficult to react with the raw material mixed powder and its reaction product. Made of carbon and carbon.

The firing container filled with the raw material mixed powder is set in a firing furnace, and preferably fired in a nitrogen atmosphere of 1500 ° C. or higher and 2200 ° C. or lower. When the firing temperature is lower than 1500 ° C., the amount of unreacted residue increases, and when the firing temperature is higher than 2200 ° C., the host crystal of the target phosphor is decomposed, which is not preferable.

The firing time is selected within a time range in which a large amount of unreacted raw material remains, the phosphor particles do not grow sufficiently, or the practical productivity is not lowered. In a preferred embodiment of the present invention, the firing time may be 1 hour or more and 24 hours or less.

The pressure of the firing atmosphere is selected according to the firing temperature. The higher the atmospheric pressure, the higher the decomposition start temperature of the base crystal of the green phosphor of the present invention, but it is preferably less than 1 MPa in view of industrial productivity.

The state of the fired product obtained by firing the raw material mixed powder varies depending on the blending ratio of the raw material mixed powder and the firing conditions, such as powder, lump, and sintered body. When used as a phosphor, the fired product can have a predetermined particle size by combining crushing, pulverization and / or classification operations.

In the production of the green phosphor of the present invention, an acid treatment step for removing impurities in the phosphor and an annealing treatment step for improving the crystallinity of the phosphor are further provided. You may do it.

The green phosphor of the present invention can be used for a light emitting device including a light emitting source and the phosphor of the present invention. In particular, when an LED that emits ultraviolet light or visible light having a wavelength of 350 nm or more and 500 nm or less is used as a light source, and the phosphor of the present invention is irradiated, green light having a fluorescence peak at a wavelength of 510 nm to 550 nm is emitted. For this reason, for example, by using an ultraviolet LED or a blue LED as a light-emitting light source and forming a light-emitting element including a combination of the green phosphor of the present invention and a red phosphor, a white light-emitting element can be easily obtained. Can do.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to the description of these examples.

Example 1
As raw materials for the phosphor of Example 1, aluminum oxide powder (Al ₂ O ₃ , TM-DAR grade, manufactured by Daimei Chemical Co., Ltd.), aluminum nitride powder (AlN, E grade, manufactured by Tokuyama Co., Ltd.), magnesium oxide powder (MgO, manufactured by Wako Pure Chemical Industries, Ltd.), manganese oxide powder (MnO, manufactured by High Purity Chemical Laboratory), Mn: Mg: Al: O: N = 0.0179: 0.0625: 0.3482: 0 5089: 0.0625 dry mix for a molar ratio of 0.0625. The mixed raw materials were classified with a nylon sieve having a mesh size of 250 μm to obtain a uniform mixed powder. 300 g of the classified raw material mixed powder was filled into a cylindrical boron nitride container with a lid (N-1 grade, manufactured by Denka).

The boron nitride container filled with the raw material mixed powder was quickly set in an electric furnace of a carbon heater, and the inside of the furnace was sufficiently evacuated to 0.1 Pa or less. While evacuating, heating was started at a heating rate of 300 ° C. per hour, and after reaching 1000 ° C., nitrogen gas was introduced into the furnace, and the atmospheric pressure in the furnace was set to 0.8 MPa. When the internal volume of the furnace was 1, the volume of nitrogen gas flowing into the furnace per minute was introduced at a ratio of 0.02, and the nitrogen gas was exhausted in parallel so that the pressure was constant. . Even after the start of the introduction of nitrogen gas, heating was continued at a heating rate of 300 ° C. per hour, the temperature was raised to 1900 ° C., and the raw material mixture was baked for 4 hours while maintaining the temperature of 1900 ° C.

After cooling for a predetermined time, a green lump was recovered from the inside of the boron nitride container recovered from the furnace. The lump was further crushed in a mortar, and finally a sieve with a mesh opening of 45 μm was obtained. A completely passed powder was obtained.

The powder that has passed through the sieve having a mesh opening of 45 μm is subjected to an acid treatment step of washing with a mixed solution of hydrofluoric acid and nitric acid (80 ° C.), and water and sodium hexametaphosphate (dispersant) The phosphor sample of Example 1 was obtained by leaving still in the mixed solvent for 10 minutes, removing fine powder by decantation, and drying.

(Example 2)
Although it operated similarly to Example 1 until completion | finish of baking, the powder which implemented the acid treatment process was made into the powder which let the sieve of 75 micrometers of meshes pass all. Furthermore, the standing time in the mixed solvent of water and sodium hexametaphosphate (dispersant) was extended to 50 minutes, and the phosphor sample of Example 2 from which fine fine powder was further removed than Example 1 was obtained. Otherwise, the same processing as in Example 1 was performed.

(Comparative Example 1)
The operation was performed in the same manner as in Example 1 until the end of firing, but the crushing after firing was performed with a ball mill, and the powder subjected to the acid treatment step was a powder that passed through a sieve having an opening of 75 μm. In addition, the phosphor sample of the comparative example 1 was obtained with the standing time in the mixed solvent of water and sodium hexametaphosphate (dispersant) being 6 minutes. Otherwise, the same processing as in Example 1 was performed.

(Comparative Example 2)
The operation was performed in the same manner as in Example 1 until the end of the baking, but the crushing after the baking was performed by a ball mill, and the powder subjected to the acid treatment step was a powder that passed through a sieve having an opening of 150 μm. The phosphor sample of Comparative Example 2 was obtained with the standing time in a mixed solvent of water and sodium hexametaphosphate (dispersant) being 10 minutes. Otherwise, the same processing as in Example 1 was performed.

(Confirmation of crystal structure)
Powder X-ray diffraction using CuKα rays was performed on the phosphor samples of Examples 1 and 2 and Comparative Examples 1 and 2 using an X-ray diffractometer (Ultima IV, manufactured by Rigaku Corporation). As for the obtained X-ray diffraction pattern, the same diffraction pattern as the AlON crystal was recognized in all samples, and it was confirmed that the main crystal phase had the same crystal structure as the AlON crystal.

(Measurement of fluorescence spectrum)
Fluorescence spectra were measured for the phosphor samples of Examples 1 and 2 and Comparative Examples 1 and 2 using a spectrofluorometer (F-7000, manufactured by Hitachi High-Technologies Corporation) corrected with rhodamine B and a substandard light source. did. For the measurement, a solid sample holder attached to the photometer was used, and a fluorescence spectrum at an excitation wavelength of 445 nm was obtained. As a result, the peak wavelength of the fluorescence spectrum was 520 nm for all samples.

(Measurement of aspect ratio and circularity)
The average value of the aspect ratios of the phosphor particles of Examples 1 and 2 and Comparative Examples 1 and 2, the percentage based on the number of particles having an aspect ratio value of 0.7 or more, and the circularity of 0.6 The above-mentioned ratio (%) based on the number of particles was measured with a particle shape image analyzer (PITA-04, manufactured by Seishin Enterprise Co., Ltd.). As a pretreatment of the phosphor before the measurement, 0.5 g of the phosphor sample was put into 100 cc of ion-exchanged water, and an ultrasonic homogenizer (Ultrasonic Homogenizer US-150E, manufactured by Nippon Seiki Seisakusho Co., Ltd.) was used. , Measured after dispersion treatment for 3 minutes under the conditions of Amplitude 100%, oscillation frequency 19.5 KHz, amplitude about 31 μm. The results are shown in Table 1. The number of particles measured was at least 100 in all cases.

(Measurement of quantum efficiency and chromaticity X of phosphor)
The green phosphor of the present invention is an invention that has led to finding an improvement in luminance by defining the value of the aspect ratio of the phosphor particles and the value of the circularity, but Examples 1 and 2 and Comparative Example 1, In order to confirm that there is no difference in the fluorescence characteristics of the phosphors of Example 2, the phosphor characteristics when excited with blue light having a wavelength of 445 nm for the phosphors of Examples 1 and 2 and Comparative Examples 1 and 2, That is, the internal quantum efficiency, the external quantum efficiency, and the chromaticity X of the phosphor were evaluated using a measurement system in which an integrating sphere is mounted on a generally known spectrophotometer. That is, a standard reflector having a reflectivity of 99% (Spectralon, manufactured by Labsphere) is 445 nm from the Xe lamp, which is a light source, in an integrating sphere (φ60 mm) set in the side opening (φ10 mm). Monochromatic light separated into wavelengths was introduced through an optical fiber, and the spectrum of the reflected light from the standard reflector was measured with a spectrophotometer (MCPD-7000, manufactured by Otsuka Electronics Co., Ltd.). In this measurement, the ambient temperature at the time of measurement was 25 ± 2 ° C., and the number of excitation light photons (Qex) was obtained from the spectrum in the wavelength range of 450 to 465 nm. Next, a concave cell filled with the phosphor sample of Example 1 is set in the opening of the integrating sphere so that the surface is smooth, and monochromatic light with a wavelength of 445 nm is irradiated, and the reflected reflected light and fluorescence spectra are excited. Was measured with a spectrophotometer. The number of excited reflected light photons (Qref) and the number of fluorescent photons (Qem) were obtained from the obtained spectrum data. The number of excited reflected light photons is the same wavelength range as the number of excited light photons, and the number of fluorescent photons is a value obtained in the wavelength range of 465 to 800 nm. From the obtained three types of photons, values of internal quantum efficiency (%) = Qem / (Qex−Qref) × 100 and external quantum efficiency (%) = Qem / Qex × 100 were calculated. Also, chromaticity X is calculated from CIE chromaticity coordinate x value (chromaticity X) in the XYZ color system defined by JIS Z 8701 according to JIS Z 8724 from data in the wavelength range of 465 nm to 780 nm of the fluorescence spectrum. did. The results are shown in Table 1. In this measurement, when a green phosphor standard sample (NIMS Standard Green, lot NSG1301, sold by Sialon Co., Ltd.) is measured, the external quantum efficiency is 55.6%, the internal quantum efficiency is 74.8%, and the chromaticity X is 0. .356. For the phosphor samples of Example 2, Comparative Example 1, and Comparative Example 2, the values of internal quantum efficiency, external quantum efficiency, and chromaticity X were determined in the same manner, and are shown in Table 1 together. From the results shown in Table 1, the internal quantum efficiency, external quantum efficiency, and chromaticity X values of the phosphors of Examples 1 and 2 and Comparative Examples 1 and 2 are almost the same, and there is no difference in the fluorescence characteristics themselves. It was confirmed.

(Production of light-emitting elements and evaluation of luminance)
When each of the phosphors of Examples 1 and 2 and Comparative Examples 1 and 2 is combined with K ₂ SiF ₆ : Mn red phosphor (KSF) (KR-101G, manufactured by Denka), the color is changed to white LED. The mixture was mixed in a vinyl bag at a ratio of degree X0.272 and chromaticity Y0.278 to obtain a phosphor mixture. 47.5 g of silicone resin (OE6656, manufactured by Toray Dow Corning) is further added to 2.5 g of each phosphor mixture, and a revolving mixer (Awatori Neritaro (registered trademark) ARE-310, Shinky Corp.) The two were mixed together to obtain a phosphor resin mixture. Each phosphor resin mixture including the phosphors of Examples 1 and 2 and Comparative Examples 1 and 2 uses a microsyringe, has an emission peak wavelength of 448 nm, and a surface dimension of 1.0 mm × 0.5 mm. Potting is performed on the surface of an LED chip in a certain unsealed state (however, electrode wiring is completed), and then the silicone resin is cured at 150 ° C., followed by post-curing at 110 ° C. for 10 hours for sealing. The light emitting devices of Examples 1 and 2 and Comparative Examples 1 and 2 were obtained. Ten light emitting elements were manufactured. The light emitting elements were energized, and their total luminous flux was measured. In addition, the value (average value) of the total luminous flux of the light emitting element of Example 2 was set to 100%, and other values were shown as relative values (average value). Note that there was almost no variation in the value of the total luminous flux between light emitting elements of the same type, and it was determined that the luminance was high when the value of the total luminous flux was 100% or more. These results are also shown in Table 1.

From the results shown in Table 1, by implementing the present invention, it is possible to provide a γ-AlON green phosphor with higher luminance, a light emitting element including the phosphor, and a light emitting device using the light emitting element. It was shown that there is.

Claims (9)

A base crystal having the same crystal structure as that of a cubic spinel AlON crystal is converted into an element M (wherein the element M is selected from Mn, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Tm, and Yb). A green phosphor in which element A or more element) and element A (wherein element A is one or more metal elements other than element M and Al) are in solid solution, the minor axis of the phosphor particles is the major axis A green phosphor having an average aspect ratio of 0.7 or more. The green phosphor according to claim 1, wherein a ratio of particles having an aspect ratio value of 0.7 or more is 50% or more of the whole particles on a number basis. The green phosphor according to claim 1 or 2, wherein the proportion of particles having a circularity value of 0.6 or more is 50% or more of the whole particles on a number basis. The composition formula is represented by MaAbAlcOdNe (where M is element M, A is element A, Al is aluminum, O is oxygen, N is nitrogen, and satisfies a + b + c + d + e = 1), and 0.00001 ≦ a ≦ 0.1 The green phosphor according to any one of claims 1 to 3, wherein The composition formula is represented by MaAbAlcOdNe (where M is element M, A is element A, Al is aluminum, O is oxygen, N is nitrogen, and a + b + c + d + e = 1 is satisfied), 0.001 ≦ b ≦ 0.40 The green phosphor according to any one of claims 1 to 4, wherein The green phosphor according to any one of claims 1 to 5, wherein the element M is Mn. The green phosphor according to claim 1, wherein the element A contains at least Mg. The light emitting element containing the green fluorescent substance as described in any one of Claims 1-7. A light emitting device using the light emitting element according to claim 8.