JP2013159718A - Manganese-activated germanate phosphor, method for preparing the same, and light-emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manganese-activated germanate phosphor which is excited by blue light and emits red light at high emission intensity, and to provide an industrially advantageous preparation method thereof.SOLUTION: A manganese-activated germanate phosphor is represented by general formula (1) (wherein M1 represents one or two or more elements selected from the group consisting of Zn, Cu, Cd, Ca, Hg, Sr and Ba, M2 represents one or two or more elements selected from the group consisting of Si, Sn and Pb, a is 0<a≤4, b is 0.5≤b≤4, c is 0.8≤c≤1.2, n is 0.001≤n≤0.05, x is 0<x≤0.25, and y is 0≤y≤0.28).

Description

  The present invention relates to a manganese-activated germanate phosphor useful as a red phosphor and a method for producing the same. The present invention also relates to a light emitting device using this manganese-activated germanate phosphor.

  In recent years, blue diodes have been put into practical use, and many studies on white light emitting diodes using these diodes as light sources are well known. Light emitting diodes have the advantages of being light, do not use mercury, and have a long life.

For example, a white light emitting diode in which Y ₃ Al ₅ O ₁₂ : Ce is coated on a blue light emitting element is known. However, strictly speaking, the light emitting diode is not white but becomes white mixed with green and blue. Therefore, it has been proposed to adjust the color tone by mixing Y ₃ Al ₅ O ₁₂ : Ce with a red phosphor that absorbs blue light and emits red fluorescence. There are many reports on red phosphors that absorb blue light and emit red fluorescence, but there are few reports on inorganic materials.

On the other hand, as general red phosphors, inorganic materials such as oxide phosphors, oxysulfide phosphors, sulfide phosphors, and nitride phosphors have been proposed, and manganese represented by the following general formula (A) An activated germanate phosphor has also been proposed (see, for example, Patent Documents 1 and 2 below).
(Wherein, a ′ + b ′ = 4, b ′ is 0.5 ≦ b ′ ≦ 1.0, and x ′ is 0.001 ≦ x ≦ 0.01).

A general method for producing a manganese-activated germanate phosphor is obtained by mixing magnesium oxide, magnesium fluoride, germanium oxide and manganese carbonate with a ball mill or the like, and firing the resulting mixture at 1000 to 1200 ° C. It is known.
For example, Patent Document 1 below proposes a method in which magnesium fluoride, magnesium oxide, germanium oxide, and manganese fluoride are mixed in a dry ball mill and fired.
Further, in Patent Document 2 below, magnesium oxide is used as a magnesium compound, and a container containing magnesium oxide, magnesium fluoride, gallium oxide and a manganese compound is moved regularly or irregularly, or by an external stirring means. There has been proposed a method for obtaining a manganese-activated germanic acid phosphor having large primary particles and not containing fine particle aggregates by firing the raw materials while stirring.
However, the conventional manganese-activated germanic acid phosphor has a problem in emission intensity and has a low quantum yield.

JP 54-158387 A JP-A-11-158464

  Accordingly, the present invention provides a manganese-activated germanate phosphor that is further improved in performance over conventional manganese-activated germanate phosphors and emits red light with high emission intensity when excited by blue light, and its industrial advantage. And a light-emitting element using the same.

  As a result of intensive studies in such circumstances, the present inventors have determined that some of the magnesium atoms are part of Zn, Cu, Cd, Ca, Hg in the manganese-activated germanate phosphor represented by a specific general formula. The inventors have found that a substance obtained by substituting a specific amount of at least one element selected from the group of Sr and Ba emits red light with a higher emission intensity than the conventional one, and completed the present invention.

The present invention has been made on the basis of the above knowledge, and the following general formula (1)
(In the formula, M1 represents one or more elements selected from the group of Zn, Cu, Cd, Ca, Hg, Sr and Ba, and M2 represents one or more elements selected from the group of Si, Sn and Pb. 2 or more elements are represented, a is 0 <a ≦ 4, b is 0.5 ≦ b ≦ 4, c is 0.8 ≦ c ≦ 1.2, n is 0.001 ≦ n ≦ 0.05, x represents 0 <x ≦ 0.25, and y represents 0 ≦ y ≦ 0.28.) A manganese-activated germanate phosphor is provided.

  The present invention is also a suitable method for producing the manganese-activated germanate phosphor, and includes M1 containing magnesium fluoride, a magnesium compound other than magnesium fluoride, a germanium compound, a manganese compound, and an M1 element. Provided is a method for producing a manganese-activated germanate phosphor, comprising a step of mixing an element-containing compound and an M2 element-containing compound containing M2 element added if necessary, and firing the resulting mixture To do.

  The present invention also provides a light emitting device using the manganese activated germanate phosphor.

  According to the present invention, a manganese-activated germanate phosphor having a high emission intensity of red light can be provided. Moreover, according to the production method of the present invention, the phosphor can be produced by an industrially advantageous method.

Hereinafter, the present invention will be described based on preferred embodiments thereof.
The manganese-activated germanate phosphor according to the present invention basically emits red light when excited with blue light. Specifically, excitation is performed with excitation light of at least 270 to 550 nm, preferably 380 to 490 nm. Further, it has an emission band in a region of 600 to 750 nm, preferably 650 to 700 nm (that is, has a red spectrum).

The manganese-activated germanate phosphor of the present invention is represented by the following general formula (1).
M1 in the general formula (1) represents one or more elements selected from the group consisting of Zn, Cu, Cd, Ca, Hg, Sr and Ba, and M2 represents a group consisting of Si, Sn and Pb. 1 type or 2 or more types of elements chosen are shown. The M1 element is an element that is partially substituted with a magnesium atom and is contained in a manganese-activated germanate phosphor to improve the emission intensity and the absorption rate of excitation light in the blue region.
In the formula (1), a is 0 <a ≦ 4, preferably 1 ≦ a ≦ 3.4, b is 0.5 ≦ b ≦ 4, preferably 0.6 ≦ b ≦ 3, and c is 0. .8 ≦ c ≦ 1.2, preferably 0.9 ≦ c ≦ 1.1, n is 0.001 ≦ n ≦ 0.05, preferably 0.005 ≦ n ≦ 0.03, x is 0 <x ≦ 0.25, preferably 0 <x ≦ 0.15. When the substitution ratio of M1 is in the above range, the emission intensity of red light is increased. On the other hand, when the value of x exceeds a specified range, the internal quantum efficiency is not improved. Further, M1 in the formula of the general formula (1) is preferable from the viewpoint of obtaining Zn having particularly high emission intensity.

  The M2 element is an element that is partially substituted with a germanium atom as required and is contained in the manganese-activated germanate phosphor to further improve the emission intensity. y is 0 ≦ y ≦ 0.28, preferably 0 ≦ y ≦ 0.25, and particularly when the range of y is 0.03 ≦ y ≦ 0.1, the emission intensity of red light and the internal quantum efficiency are further improved. Can be improved. Further, M2 in the formula of the general formula (1) is preferable from the viewpoint of obtaining Si having particularly high emission intensity.

  The manganese-activated germanate phosphor of the present invention is a powder, and the particle shape is not particularly limited. The particle shape may be, for example, spherical, polyhedral, spindle shape, needle shape, or indefinite shape.

  The manganese-activated germanate phosphor of the present invention preferably has an average particle size of 1 to 50 μm, particularly 5 to 45 μm. By having an average particle diameter in this range, excitation light can be absorbed more efficiently. On the other hand, when the average particle size is less than 1 μm, the excitation light is likely to be scattered, and the absorption efficiency of the excitation light tends to decrease. When the average particle size is more than 50 μm, the particle surface area becomes small, and the absorption of excitation light tends to be insufficient. The average particle diameter referred to in the present invention is the average particle diameter of secondary particles formed by aggregation of primary particles. The average particle diameter is a median diameter. The average particle diameter (median diameter) of the secondary particles is measured by, for example, a laser diffraction / scattering particle size distribution measuring apparatus (model number LA920) manufactured by Horiba, Ltd., the refractive index of the sample is 1.81, and the refractive index of the dispersion medium is 1. .33 can be calculated on a volume basis.

  The average particle diameter can be adjusted, for example, as follows. That is, the fired product of the manganese-activated germanate phosphor obtained in the firing step described below is subjected to a grinding treatment by an automatic mortar or a ball mill, etc. By carrying out, a powder having a desired average particle diameter can be obtained.

Manganese-activated germanate salt phosphor of the present invention preferably has a BET specific surface area of 0.1 to 100 m ² / g, particularly 1 to 50 m ² / g. When the BET specific surface area is set in this range, excitation light can be sufficiently absorbed and excitation light can be prevented from scattering, so that the emission intensity can be sufficiently increased. On the other hand, when the BET specific surface area is less than 0.1 m ² / g, absorption of excitation light tends to be insufficient. When the BET specific surface area is more than 100 m ² / g, the average particle size is small with the increase of the surface area, so that the excitation light may be scattered and the absorption of the excitation light may be insufficient. The BET specific surface area can be measured using, for example, a BET method monosorb specific surface area measuring apparatus (Flowsorb II 2300) manufactured by Shimadzu Corporation.

  The BET specific surface area can be adjusted, for example, as follows. That is, the fired product of the manganese-activated germanate phosphor obtained in the firing step described below is subjected to a grinding treatment by an automatic mortar or a ball mill, etc. By carrying out, a powder having a desired BET specific surface area can be obtained.

Subsequently, the preferable manufacturing method of the manganese activation germanate fluorescent substance of this invention is demonstrated.
The method for producing a manganese-activated germanate phosphor having the above composition according to the present invention includes magnesium fluoride, a magnesium compound other than magnesium fluoride (hereinafter simply referred to as “magnesium compound”), a germanium compound, a manganese compound, and an M1 element. M1 element-containing compound (hereinafter simply referred to as “M1 element-containing compound”) and M2 element-containing compound (hereinafter simply referred to as “M2 element-containing compound”) containing M2 element added as necessary And firing the resulting mixture. That is, the method for producing a manganese-activated germanate phosphor of the present invention roughly includes (a) a mixing step and (b) a firing step.

  In the mixing step (a), a uniform mixture is prepared in which magnesium fluoride, magnesium compound, germanium compound, manganese compound, M1 element-containing compound and M2 element-containing compound added as necessary are uniformly mixed.

  A preferable physical property of the first raw material magnesium fluoride is that the average particle diameter is 10 μm or less, preferably 1 to 10 μm, and particularly preferably 0.1 to 1 μm, from the viewpoint of easy uniform mixing.

  As the second raw material magnesium compound, in addition to magnesium oxide, those that can be converted into magnesium oxide in the firing step (b) described later are used. As such a magnesium compound, for example, magnesium carbonate, oxalate, sulfate, hydroxide and the like can be used. These compounds can use 1 type (s) or 2 or more types. Among these, magnesium hydroxide is preferably used in that impurities do not remain after firing and the reactivity between raw materials is high. A preferable physical property of the magnesium compound is that the average particle size is 5 μm or less, preferably 0.2 to 5 μm, and particularly preferably 0.2 to 2 μm, from the viewpoint of easy uniform mixing.

  As the third raw material germanium compound, in addition to germanium oxide, one that can be converted into germanium oxide in the later-described (b) firing step is used. As such a germanium compound, for example, germanium carbonate, sulfate, nitrate, hydroxide, organic acid salt and the like can be used. These compounds can use 1 type (s) or 2 or more types. Among these, germanium oxide is preferably used from the viewpoint of easy composition adjustment by wet mixing because it has low volatility and is hardly hydrolyzed by moisture. A preferable physical property of the germanium compound is that the average particle diameter is 50 μm or less, particularly 1 to 30 μm, from the viewpoint of easy uniform mixing.

  As the fourth raw material manganese compound, for example, in addition to the oxide of manganese, one that can be converted to manganese oxide in the later-described (b) firing step is used. As such a manganese compound, manganese hydroxide, carbonate, nitrate, sulfate, organic acid salt and the like can be used. These compounds can use 1 type (s) or 2 or more types. Among these, manganese carbonate is preferable in that impurities do not remain after firing and it is easily dissolved in the base crystal. A preferable physical property of the manganese compound is that the average particle size is 10 μm or less, particularly 1 to 9 μm, from the viewpoint of easy uniform mixing.

Examples of the fifth raw material M1 element-containing compound include oxides, hydroxides, halides, carbonates, nitrates, and organic acid salts containing the M1 element. These compounds can use 1 type (s) or 2 or more types. A preferable physical property of the M1 element-containing compound is that the average particle diameter is 10 μm or less, particularly 0.01 to 9 μm, from the viewpoint that uniform mixing can be easily performed.
The M1 element-containing compound is preferably a compound containing Zn. In particular, zinc oxide is preferably used from the viewpoint of easy composition adjustment by wet mixing because zinc oxide hardly reacts with water and is not hydrolyzed.

In the present invention, the emission intensity of red light and the internal quantum efficiency can be further improved by containing the M2 element-containing compound as a sixth raw material in the mixture as needed in addition to the first to fifth raw materials. .
Examples of the M2 element-containing compound as the sixth raw material include oxides, hydroxides, halides, carbonates, nitrates, and organic acid salts containing the M2 element. In addition, in the case of a compound containing Si as the M2 element-containing compound, silicon, silicon carbide, silicon nitride, silicon boride and the like can be used in addition to the above.
These compounds can use 1 type (s) or 2 or more types. A preferable physical property of the M2 element-containing compound is that the average particle size is 10 μm or less, particularly 0.01 to 9 μm, from the viewpoint that uniform mixing can be easily performed.
The M2 element-containing compound is preferably a compound containing Si. In particular, silicon dioxide is preferably used from the viewpoint of easy composition adjustment by wet mixing because silicon dioxide does not easily react with water and is not hydrolyzed.

  Production history of the above-described magnesium fluoride, magnesium compound, germanium compound, manganese compound, M1 element-containing compound and M2 element-containing compound added as necessary is not limited, but to produce a high-purity manganese-activated germanate phosphor. In addition, it is preferable that the impurity content is as low as possible.

In this production method, the mixing ratio of magnesium fluoride, magnesium compound, germanium compound, manganese compound, M1 element-containing compound, and M2 element-containing compound added as required is the composition of the desired manganese-activated germanate phosphor described above. The mixing ratio of each raw material may be appropriately selected according to the above.
Specifically, when the M2 element-containing compound is not added, the mixing ratio of magnesium fluoride, magnesium compound, germanium compound, manganese compound, and M1 element-containing compound is such that the amount of magnesium fluoride added is germanium in the germanium compound. The molar ratio of the number of magnesium fluoride molecules to the total number of atoms, manganese atoms in the manganese compound, and M1 atoms in the M1 element compound (MgF ₂ / (Ge + Mn + M1)) is 0.5 to 4, preferably 0.6. ~ 3. The amount of magnesium compound added is the molar ratio of the number of magnesium atoms in the magnesium compound to the total number of germanium atoms in the germanium compound, manganese atoms in the manganese compound, and M1 atoms in the M1 element-containing compound (Mg / (Ge + Mn + M1)) greater than 0 and 4 or less, preferably 1 to 3.4. The addition amount of the manganese compound is the molar ratio of the number of manganese atoms in the manganese compound to the total number of germanium atoms in the germanium compound, manganese atoms in the manganese compound, and M1 atoms in the M1 element-containing compound (Mn / (Ge + Mn + M1)) is 0.001 to 0.05, preferably 0.005 to 0.03. The amount of the M1 element-containing compound added is the molar ratio (M1 / Mg + M1) of the number of M1 atoms in the M1 element-containing compound to the total number of magnesium atoms in the magnesium compound and the M1 atom in the M1 element-containing compound. It is preferable to be greater than 0 and not greater than 0.25, preferably greater than 0 and not greater than 0.15.
When the M2 element-containing compound is added, the amount of the M2 element-containing compound added is the number of M2 atoms in the M2 element-containing compound relative to the total number of germanium atoms in the germanium compound and M2 atoms in the M2 element-containing compound. The molar ratio (M2 / Ge + M2) is more than 0 and 0.28 or less, preferably more than 0 and 0.15 or less, and more preferably 0.03 to 0.1.

  As a method of mixing the first to sixth raw materials of magnesium fluoride, magnesium compound, germanium compound, manganese compound, M1 element-containing compound and M2 element-containing compound added if necessary, both wet method and dry method are used. Although it is possible, it is preferable that the wet process is performed by mechanical means because a uniform mixture in which the raw materials are uniformly mixed can be easily obtained. In particular, by performing a mixing process by a wet method using a media mill, which is a device capable of simultaneously performing pulverization and mixing, a homogeneous mixture can be obtained more easily, and a manganese-activated germanate fluorescent obtained using the homogeneous mixture can be obtained. The body has particularly high emission intensity.

The mixing process using the media mill will be further described.
The mixing process in the media mill basically includes a slurry preparation process and a mixing process in which the obtained slurry is introduced into the media mill and the mixing process is performed.

In the slurry preparation step, magnesium fluoride, a magnesium compound, a germanium compound, a manganese compound, an M1 element-containing compound and an M2 element-containing compound added as necessary are dispersed in a dispersion medium to form a slurry. As the dispersion medium, either water or a non-aqueous dispersion medium can be used. From the viewpoint of easy handling, it is preferable to use water or an aqueous solution in which a water-soluble organic solvent is blended in water as the dispersion medium.
In addition, when the mixing process is performed by a wet method using a media mill, the first to sixth raw materials magnesium fluoride, magnesium compound, germanium compound, manganese compound, M1 element-containing compound, and M2 element-containing compound added as necessary It is preferable to use a material that is hardly soluble or insoluble in the dispersion medium from the viewpoint of easy control of the particle diameter and composition adjustment.

  The solid content concentration of the slurry (magnesium fluoride, magnesium compound, germanium compound, manganese compound, M1 element-containing compound and M2 element-containing compound added if necessary) is 5 to 40% by weight, preferably 10 to 30%. It is preferable from the viewpoint that the treatment scale is small, operability is easy, and mixing using a media mill can be performed efficiently.

  From the viewpoint of more efficiently performing the treatment using the media mill, a dispersant may be added to the mixed slurry. By adding the dispersant, the magnesium fluoride, the magnesium compound, the germanium compound, the manganese compound, the M1 element-containing compound, and the M2 element-containing compound added as necessary are more uniformly dispersed in the dispersion medium. As a result, a uniform mixture of these raw materials can be obtained more easily. What is necessary is just to select a suitable dispersing agent to use according to the kind of dispersion medium. When the dispersion medium is water, various surfactants, polycarboxylic acid ammonium salts, and the like can be used as the dispersant. The concentration of the dispersant in the mixed slurry is preferably 0.01 to 10% by weight, particularly 0.1 to 5% by weight from the viewpoint of obtaining a sufficient dispersion effect.

  Next, the slurry obtained in the slurry preparation step is introduced into a media mill and mixed to obtain a uniform mixture. As the media mill, a bead mill, a ball mill, a paint shaker, an attritor, a sand mill, or the like can be used. It is particularly preferable to use a bead mill. In that case, the operating conditions and the type and size of the beads may be appropriately selected according to the size and processing amount of the apparatus and the type of raw material to be used.

  The mixing treatment by a wet method using a media mill may be performed until the average particle size of solids (average particle size of secondary particles) is 10 μm or less, particularly 0.1 to 8 μm. Is preferable from the viewpoint that high emission efficiency can be obtained. This average particle diameter can be measured by a light scattering particle size distribution measuring apparatus.

The uniform mixture is recovered by filtration from the uniform mixed slurry obtained in the mixing step (a). The recovered mixture is preferably subjected to a drying treatment before being subjected to the firing step (b). The drying treatment can be performed, for example, at 80 to 200 ° C. for 1 to 100 hours.
In addition, you may perform a drying process with the spray dryer etc. which dry the whole slurry after the wet-mixing process.

  As described above, the homogeneous mixture obtained in the mixing step (A) is subjected to the firing step (B) to obtain a manganese-activated germanate phosphor. When firing is performed at a firing temperature of 1025 to 1250 ° C., particularly 1050 to 1200 ° C., a single target composition can be obtained, and the particle surface can be made smoother, with high luminous efficiency. Is particularly preferable from the viewpoint that can be obtained. When the firing temperature is less than 1025 ° C., it is difficult to obtain a single composition, and it is difficult to dissolve the luminescent ions. On the other hand, when the firing temperature exceeds 1250 ° C., dissolution starts and the particle shape cannot be maintained. It tends to be difficult to obtain a uniform powder. The firing time is generally 1 hour or longer, particularly 3 hours or longer, preferably 5 to 36 hours. The firing atmosphere is not particularly limited, and may be any of an oxidizing gas atmosphere such as air and an inert gas atmosphere.

  The fired body obtained in this way may be subjected to a plurality of firing steps as necessary. After firing, the resulting manganese-activated germanate phosphor may be crushed or crushed as necessary, and further classified.

Thus, a manganese-activated germanate phosphor is obtained as a single composition, and the preferred physical properties of the manganese-activated germanate phosphor are an average particle size determined by a light scattering particle size distribution analyzer of 1 to 50 μm. The thickness is preferably 5 to 45 μm. When the average particle diameter is in the above range, excitation light can be absorbed more efficiently. BET specific surface area of 0.1 to 100 m ² / g, preferably from 1 to 50 m ² / g. When the BET specific surface area is in the above range, absorption of excitation light becomes sufficient, and scattering of excitation light can also be prevented, so that the emission intensity can be sufficiently increased.

The manganese-activated germanate phosphor of the present invention can be further surface-treated with a metal oxide as necessary for the purpose of improving moisture resistance.
Examples of the metal oxide include Be, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Sr, Y, Zr, and Nb. , Mo, Cd, In, Sn, Sb, Te, Ba, La, Hf, Ta, W, Tl, Pb, Bi, Ce, Pr, Nb, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er , Tm, Yb, Lu, Th, Pa, U, and a metal oxide containing two or more metal elements selected from Pu and Pu are used.
As a method for coating the surface of the particles of the manganese-activated germanate phosphor with these metal oxides, a known method can be used. For example, using a metal alkoxide containing the metal element, The metal alkoxide is added to a slurry or suspension containing the manganese-activated germanate phosphor particles, and a hydrolysis reaction of the metal alkoxide is performed in the presence of an acid catalyst or an alkali catalyst, if necessary. Examples thereof include a method of uniformly treating the particle surface of the acid salt phosphor with the metal oxide.

  The manganese-activated germanate phosphor thus obtained can be suitably used as a red phosphor, and the red phosphor can be used for display devices such as electrolytic emission displays, plasma displays, and electroluminescence. It can be used for various issuing elements. Moreover, since it has an excitation spectrum close to around 450 nm, it can be applied to a blue LED excitation phosphor. It is particularly suitable for use in electroluminescent display devices. Also, by a method using in combination with a blue excited green phosphor, a method using in combination with a blue LDE element and a blue excited green phosphor, or a method using in combination with a blue LDE element and a blue excited yellow light emitting phosphor, etc. It can also be applied to white LEDs.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. Unless otherwise specified, “%” means “% by weight”.

The average particle diameter and BET specific surface area in the following examples and comparative examples were measured as follows.
Average particle diameter: Measured with a laser diffraction / scattering particle size distribution analyzer (model number LA920) manufactured by HORIBA, Ltd., and calculated on a volume basis with the refractive index of the sample being 1.81 and the refractive index of the dispersion medium being 1.33.
BET specific surface area: Measured using a BET method monosorb specific surface area measuring apparatus (Flowsorb II 2300) manufactured by Shimadzu Corporation.

[Example 1]
(A) uniform slurry preparation process;
Magnesium hydroxide (average particle size 0.57 μm), zinc oxide (average particle size 0.33 μm), magnesium fluoride (average particle size 19.0 μm), germanium oxide (average particle size 17.7 μm), silicon dioxide (average) Particle size 0.016 μm) and manganese carbonate (average particle size 5.2 μm), the molar ratio of MgF ₂ : Mg: Zn: Ge: Si: Mn is 1: 2.6: 0.4: 0.94: 0. .05: 0.01 Weighed to 0.01 and charged into a ball mill. Water and a dispersant (manufactured by Kao Corporation, Poise 2100) were added to the ball mill to prepare a mixed solution having a solid content concentration of 15%. The concentration of the dispersant was 2%. The molar ratio of Mg indicates a molar ratio derived only from magnesium hydroxide.
A ball mill was charged with zirconia balls having a diameter of 2 mm and mixed and ground by a wet method for 15 hours. The average particle size of the solid content of the slurry after mixing and pulverization was measured by a light scattering method to be 0.3 μm.
Next, the mixture was recovered from the slurry by filtration and dried at 120 ° C. for 15 hours to obtain a dry powder. The average particle size of the dry powder was 0.5 μm.
(B) firing step;
Next, the dry powder was charged into an electric furnace and fired in the air at 1,150 ° C. for 6 hours.
In this _{manner, 3 (Mg 0.866 Zn 0.133)} O · 1MgF 2 · of interest _{{(Ge 0.94 Si 0.05) O} 2}: manganese activated germanate salt is 0.01Mn ⁴⁺ A phosphor was obtained.
When the obtained manganese-activated germanate phosphor was subjected to X-ray diffraction measurement, the manganese-activated germanate phosphor was composed of Mg ₁₄ Ge ₅ O ₂₄ and MgO by X-ray diffraction. It was confirmed that the composition was a manganese-activated germanate phosphor.

[Example 2]
In the step (a) of preparing the uniform mixed slurry in Example 1, magnesium hydroxide (average particle size 0.57 μm), zinc oxide (average particle size 0.33 μm), magnesium fluoride (average particle size 19.0 μm), oxidation Germanium (average particle size 17.7 μm), silicon dioxide (average particle size 0.016 μm) and manganese carbonate (average particle size 5.2 μm) are mixed at a molar ratio of MgF ₂ : Mg: Zn: Ge: Si: Mn of 1. : 2.8: 0.2: 0.94: 0.05: 0.01 and 3 (Mg _0.933 Zn _{0.067) in the same} manner as in Example 1 except that it was weighed so as to be in a ball mill and charged in a ball mill. ) O · 1MgF ₂ · {(Ge _0.94 Si _0.05 ) O ₂ }: A manganese-activated germanate phosphor of 0.01Mn ⁴⁺ was obtained. When the obtained manganese activated germanate phosphor was subjected to X-ray diffraction measurement, it was X-ray diffractionly composed of Mg ₁₄ Ge ₅ O ₂₄ and MgO, and single-composition manganese-activated germanate fluorescence. I confirmed that it was a body.

Example 3
In the step (a) of preparing the uniform mixed slurry in Example 1, magnesium hydroxide (average particle size 0.57 μm), zinc oxide (average particle size 0.33 μm), magnesium fluoride (average particle size 19.0 μm), oxidation Germanium (average particle size 17.7 μm), silicon dioxide (average particle size 0.016 μm) and manganese carbonate (average particle size 5.2 μm) are mixed at a molar ratio of MgF ₂ : Mg: Zn: Ge: Si: Mn of 1. : 2.4: 0.6: 0.94: 0.05: except that charged to the weighed ball mill so as to 0.01 in the same manner as in example 1 _{3 (Mg} 0.8 _{Zn 0.2} ) O · 1MgF ₂ · {(Ge _0.94 Si _0.05 ) O ₂ }: A manganese-activated germanate phosphor of 0.01Mn ⁴⁺ was obtained. The obtained manganese-activated germanate phosphor was subjected to X-ray diffraction measurement, and was X-ray diffractionly composed of Mg ₁₄ Ge ₅ O ₂₄ , MgO and ZnO, and a composition containing a small amount of impurity phase. This was confirmed to be a manganese-activated germanate phosphor.

[Comparative Example 1]
In the step (a) of preparing a uniform mixed slurry in Example 1, magnesium hydroxide (average particle size 0.57 μm), magnesium fluoride (average particle size 19.0 μm), germanium oxide (average particle size 17.7 μm), and carbonic acid Example 1 except that manganese (average particle size of 5.2 μm) was weighed so that the molar ratio of MgF ₂ : Mg: Ge: Mn was 1: 3: 0.99: 0.01 and charged in a ball mill. in the same manner as to _{3MgO · MgF 2 · Ge 0.99 O} 2: to obtain a manganese-activated germanate salt phosphor is 0.01Mn ^4+. When the obtained manganese activated germanate phosphor was subjected to X-ray diffraction measurement, it was X-ray diffractionly composed of Mg ₁₄ Ge ₅ O ₂₄ and MgO, and single-composition manganese-activated germanate fluorescence. I confirmed that it was a body.

[Comparative Example 2]
In the step (a) of preparing the uniform mixed slurry in Example 1, magnesium hydroxide (average particle size 0.57 μm), zinc oxide (average particle size 0.33 μm), magnesium fluoride (average particle size 19.0 μm), oxidation Germanium (average particle size 17.7 μm), silicon dioxide (average particle size 0.016 μm) and manganese carbonate (average particle size 5.2 μm) are mixed at a molar ratio of MgF ₂ : Mg: Zn: Ge: Si: Mn of 1. : 1.8: 1.2: 0.94: 0.05: except that charged to the weighed ball mill so as to 0.01 in the same manner as in example 1 _{3 (Mg} 0.6 _{Zn 0.4} ) O · 1MgF ₂ · {(Ge _0.94 Si _0.05 ) O ₂ }: A manganese-activated germanate phosphor of 0.01Mn ⁴⁺ was obtained. The obtained manganese-activated germanate phosphor was subjected to X-ray diffraction measurement. As a result, it was X-ray diffractionly composed of Mg ₁₄ Ge ₅ O ₂₄ , MgO, ZnO ₄ and Zn ₂ GeO _4. It was confirmed that it was a manganese-activated germanate phosphor.

[Reference Example 1]
In Example 1, (a) uniform mixed slurry preparation step, magnesium hydroxide (average particle size 0.57 μm), magnesium fluoride (average particle size 19.0 μm), germanium oxide (average particle size 17.7 μm), dioxide dioxide Silicon (average particle size 0.016 μm) and manganese carbonate (average particle size 5.2 μm) were mixed at a molar ratio of MgF ₂ : Mg: Ge: Si: Mn of 1: 3: 0.94: 0.05: 0. 01 become so weighed 3MgO _· MgF _{2 ·} except that charged into a ball mill in the same manner as in example _{1 {(Ge 0.94 Si 0.05)} O 2}: manganese-activated germanate is 0.01Mn ⁴⁺ An acid salt phosphor was obtained. When the obtained manganese activated germanate phosphor was subjected to X-ray diffraction measurement, it was X-ray diffractionly composed of Mg ₁₄ Ge ₅ O ₂₄ and MgO, and single-composition manganese-activated germanate fluorescence. I confirmed that it was a body.

[Physical property evaluation of manganese-activated germanate phosphor]
For the manganese-activated germanate phosphors obtained in Examples, Comparative Examples and Reference Examples, the average particle diameter and BET specific surface area were measured by the methods described above, and the results are shown in Table 2.

[Evaluation as a red phosphor]
About the manganese activation germanate fluorescent substance obtained by the Example, the reference example, and the comparative example, the internal quantum efficiency and the relative light emission intensity in excitation wavelength 450nm were measured with the following method. The results are shown in Table 3 below.

[Internal quantum efficiency]
Using a fluorescence spectrophotometer (F-7000) manufactured by Hitachi High-Tech, Inc. and an attached integrating sphere, the excitation light was 450 nm, and the conversion efficiency was obtained by scanning the range from 420 to 700 nm. An aluminum oxide powder was used as a sample for measuring the total scattered light. The spectral intensity integrated value of 435 to 475 nm obtained by aluminum oxide is used as the excitation light amount, and the spectral intensity integrated value of 435 to 475 nm obtained by the phosphor sample is used as the excitation light amount after absorption, and from 600 obtained by the phosphor sample. The integral value of spectral intensity at 700 nm was determined as the amount of fluorescence. And the internal quantum efficiency was calculated | required from the following formula | equation (1).
Internal quantum efficiency (%) = 100 × fluorescence amount / (excitation light amount−excitation light amount after absorption) (1)

[Relative emission intensity]
Using a fluorescence spectrophotometer (F-7000) manufactured by Hitachi High-Tech Co., Ltd., excitation light was set to 450 nm, and a range from 470 to 800 nm was scanned to obtain a fluorescence spectrum. The relative light emission intensity was determined from the obtained intensity value with the maximum light emission intensity being 100.

As is clear from the results shown in Table 3, the manganese-activated germanate phosphor (product of the present invention) obtained by substituting a part of magnesium of Example 1 with a zinc atom is a part of the magnesium of Reference Example 1 with a zinc atom. It can be seen that the emission intensity in the red region is higher than that of the manganese-activated germanate phosphor not substituted with.

Claims (11)

The following general formula (1)
(In the formula, M1 represents one or more elements selected from the group of Zn, Cu, Cd, Ca, Hg, Sr and Ba, and M2 represents one or more elements selected from the group of Si, Sn and Pb. 2 or more elements are represented, a is 0 <a ≦ 4, b is 0.5 ≦ b ≦ 4, c is 0.8 ≦ c ≦ 1.2, n is 0.001 ≦ n ≦ 0.05, x represents 0 <x ≦ 0.25, and y represents 0 ≦ y ≦ 0.28.) A manganese-activated germanate phosphor characterized in that   The manganese-activated germanate phosphor according to claim 1, which emits light by excitation light of 270 to 550 nm.   The manganese-activated germanate phosphor according to claim 1 or 2, having an emission band in a region of 600 to 750 nm.   The manganese-activated germanate phosphor according to any one of claims 1 to 3, having an average particle size of 1 to 50 µm.   5. The manganese-activated germanate phosphor according to claim 1, wherein M1 in the formula of the general formula (1) is Zn.   6. The manganese-activated germanate phosphor according to claim 1, wherein M2 in the general formula (1) is Si. A method for producing the manganese-activated germanate phosphor according to claim 1,
Mixture obtained by mixing magnesium fluoride, magnesium compound other than magnesium fluoride, germanium compound, manganese compound, M1 element-containing compound containing M1 element and M2 element-containing compound containing M2 element added if necessary The manufacturing method of the manganese activation germanate fluorescent substance characterized by including the process of baking.   The method for producing a manganese-activated germanate phosphor according to claim 7, wherein the firing temperature is 1025 to 1250 ° C.   The method for producing a manganese-activated germanate phosphor according to claim 7 or 8, wherein the M1 element-containing compound containing the M1 element is zinc oxide.   10. The method for producing a manganese-activated germanate phosphor according to claim 7, wherein the M2 element-containing compound containing the M2 element is silicon dioxide.   A light-emitting device using the manganese-activated germanate phosphor according to any one of claims 1 to 6.