JP2002080846A - Zinc gallate powder, phosphor comprising the same, and their production methods - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zinc gallate powder which has an isotropic shape and a controlled particle size and is useful a phosphor for electron beam excitation. SOLUTION: In a process for producing a zinc gallate powder by mixing a gallium compound powder with a zinc compound powder and baking the resultant mixture, the sizes and shapes of the gallium compound and zinc compound are suitably set.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zinc gallate powder useful as a phosphor, a phosphor using the same, and a method for producing the same.

[0002]

_2. Description of the Related Art Zinc gallate is useful as a phosphor for exciting an electron beam, and is a self-activated (ZnGa ₂ O ₄ ) blue phosphor or a Mn activated (ZnGa ₂ O ₄ : Mn) green phosphor. Phosphors are known. These are fluorescent display tubes (Vacuu).
m Fluorescent Display: VFD)
And field emission displays (Field Emissio)
m Display (FED).

[0003] As a conventional method for producing a zinc gallate phosphor, a method in which zinc oxide and gallium oxide powder as starting materials are calcined together with a flux component such as a phosphate compound is disclosed in, for example, JP-A-3-166289. Kaihei 8-1
No. 38548. According to this production method, it is necessary to finely pulverize the calcined product in order to make zinc gallate into a predetermined particle size, and then to dissolve and wash the remaining phosphate compound.

In this manufacturing method, a large energy is given to the surface of the phosphor particles during the pulverizing step,
Surface defects are generated by the mechanochemical action. Also,
Mixing of impurities during the grinding operation is inevitable. On the surface of such a phosphor, a sufficiently high luminance could not be obtained because the luminous efficiency was low. In addition, variations in luminance between particles occur, making it difficult to produce a phosphor with stable luminance. Therefore, there is a demand for a method for producing a phosphor having a uniform particle diameter without a pulverizing operation.

[0005] As a production method that does not require pulverization, Japanese Patent Laid-Open No.
No. 000-80363 discloses a method of manufacturing using GaOOH, but in this case, only phosphor particles having a large aspect ratio are obtained. With such columnar particles, it was difficult to obtain a uniform coating film.

[0006] For this reason, it has been desired that the phosphor particles have a uniform particle diameter and an isotropic particle shape.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a zinc gallate powder having an isotropic shape and a controlled particle diameter, which is useful as a phosphor for exciting an electron beam.

[0008]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, mixed and fired a gallium compound powder and a zinc compound powder to produce a zinc gallate powder. In the process, it has been found that by appropriately setting the particle diameter and the particle shape of the gallium compound powder and the zinc compound powder used as the raw materials, it is possible to produce a zinc gallate powder having the intended particle diameter and particle shape. Further, NH ₄ Ga ₃ (SO ₄ ) ₂ (OH) ₆ .having a polyhedral particle shape as the gallium compound powder.
The inventors have found that H ₂ O is suitable, and have completed the present invention.

Hereinafter, the present invention will be described in detail.

[0010] The zinc gallate powder is produced in such a form that a zinc raw material (eg, zinc oxide powder, a salt of zinc chloride, etc.) infiltrates a gallium raw material (eg, gallium oxide powder, gallium compound powder, etc.). proceed. For this reason, a zinc gallate powder is generated that substantially reflects the shape of the gallium compound particles that are the gallium raw material.

From this fact, it is possible to obtain a desired particle size by using a gallium raw material (for example, gallium oxide powder, gallium compound powder, etc.) having a controlled particle diameter and particle shape, mixing with a zinc raw material having a controlled particle size, and firing. And zinc gallate powder in the form of particles can be produced.

In the present invention, the volume average particle diameter is from 1 to 20 in order to achieve both a sufficient emission intensity and good coating characteristics.
It is an isotropic zinc gallate powder of μm. Preferably, it is 1 to 10 μm. Here, the isotropic shape is spherical,
It shows an isotropic particle shape such as a cube. More strictly, the maximum value of the distance from one point to a different point on the surface of the powder is defined as the maximum particle diameter X. Furthermore, the vertical 2 of this straight line X
The minimum value at two points where the bisector meets the powder is defined as the minimum diameter Y. At this time, a powder satisfying 1 ≦ (maximum diameter / minimum diameter = X / Y) ≦ 2 is defined as isotropic.

In order to obtain the above zinc gallate powder, the gallium raw material preferably has a volume average particle diameter of 1 to 20 μm, more preferably 1 to 10 μm. The particle shape of the gallium raw material is preferably an isotropic particle such as a sphere or a cube.

The gallium raw material in the present invention is not particularly limited. For example, gallium oxide powder, NH ₄ Ga ₃ (SO ₄ ) ₂ (OH) ₆ .H ₂ O, GaOO
H, Ga (OH) ₃ , Ga ₂ (C ₂ O ₄ ) ₃ , Ga ₂ (S
It is preferable to use a raw material that generates substantially only gallium oxide powder by heating such as O ₄ ) ₃ .

The above gallium compound powder may be spherical particles composed of a collection of amorphous or microcrystals obtained by hydrolysis of an alkoxide, or may be single crystal particles having an isotropic crystal outer shape. .

As an example of a gallium compound powder whose particle shape is isotropic and whose particle size can be controlled, NH ₄ Ga ₃ (SO
₄ ) A case where ₂ (OH) ₆ .H ₂ O is used as a raw material will be described. Gallium compound powder (NH ₄ Ga ₃ (SO ₄ ) ₂
(OH) ₆ .H ₂ O) tends to grow as isotropic polyhedral crystal particles in an aqueous solution. Here, the isotropic polyhedron is
It shows a polyhedral shape such as a cubic or octahedral shape and isotropic particle shape with relatively good symmetry. The gallium compound powder can easily take a cubic or octahedral shape, but need not be a complete cubic or octahedral polyhedron.

Gallium compound powder (NH ₄ Ga ₃ (S
The method for synthesizing O ₄ ) ₂ (OH) ₆ .H ₂ O) is not particularly limited, and an example is shown below.

By adding a substance containing a sulfate ion and an ammonium ion to a solution of a salt of gallium element of 0.01 to 1 mol / l and heating and reacting at a temperature of 50 ° C. or more for 1 hour or more, isotropic particles are obtained. Gallium compound powder (NH ₄ Ga ₃ (SO ₄ ) ₂ (O
H) ₆ · H ₂ O) can be obtained.

Gallium salts include gallium chloride, gallium nitrate, gallium sulfate, gallium acetate, etc., sulfuric acid raw materials include sulfuric acid and ammonium sulfate, and ammonia raw materials include ammonia, ammonium sulfate, ammonium chloride, ammonium nitrate and the like. Used. The amount of each of the sulfate ion and the ammonium ion is preferably from 0.2 mol to 10 mol per mol of the gallium element.

Under the above conditions, gallium compound powder (NH ₄ Ga) having a controllable particle size distribution and an isotropic particle shape
₃ (SO ₄ ) ₂ (OH) ₆ .H ₂ O) can be obtained.

As zinc raw materials, zinc oxide, zinc chloride,
Zinc compound powder which is a salt of zinc such as zinc nitrate, zinc sulfate, zinc oxalate and the like can be mentioned. Also, the zinc raw material is
In order to react uniformly and promptly with the gallium raw material and to maintain the shape of the gallium raw material even after the reaction, the particle size of the zinc raw material is determined by the ratio of the particle size of the zinc raw material to the particle size of the gallium raw material (volume of the zinc raw material) (Average particle diameter / volume particle diameter of the gallium raw material) is preferably 1 or less. For example, a zinc compound powder having a particle diameter ratio (volume average particle diameter of zinc compound powder / volume average particle diameter of gallium compound powder) of 1 or less is preferable. Furthermore, the ratio of the particle diameters (volume average particle diameter of the zinc raw material / volume particle diameter of the gallium raw material)) is 0.1
The following fine powder zinc raw materials are more preferable. As the zinc raw material of the fine powder, a mechanically pulverized material may be used, or fine particles neutralized and precipitated from a solution may be used.

In mixing the zinc raw material (zinc compound powder), zinc oxide is mixed in a wet or dry manner. Alternatively, a gallium compound powder is introduced into an acidic or neutral solution of a zinc salt such as zinc chloride or zinc nitrate, and a zinc precipitate is obtained by a neutralization precipitation reaction with ammonia or oxalic acid, and the precipitate is filtered and dried. It is also possible.

By baking the mixture of the above-mentioned gallium raw material and zinc raw material at 800 to 1400 ° C. for 1 hour or more, it is possible to prepare an almost single-phase isotropic polyhedral zinc gallate powder. In consideration of the fact that gallium oxide powder is produced in addition to zinc gallate powder, the mixing amount of zinc is 0.4 to 0.4 mol / gallium.
0.6 mole is preferred.

In order to obtain a phosphor having good luminous efficiency, it is effective to activate the luminescent center by performing reduction firing after adjusting the zinc gallate powder, if necessary. In order to obtain ZnGa ₂ O ₄ : Mn which is a green phosphor, ZnGa ₂
O ₄ can be produced by adding and activating a manganese raw material as an activator during or after preparation of O ₄ .

As the manganese raw material as the activator, for example, manganese salts such as manganese sulfate, manganese nitrate, and manganese carbonate are used. The method of addition may be dry or wet mixing, or after adding a manganese raw material dissolved in a solution, the mixture may be dried. Considering the emission intensity of green light, the amount of manganese as an activator is preferably 0.1 to 3 mol% with respect to 1 mol of zinc gallate.

The zinc gallate powder thus prepared is an isotropic particle having a controlled particle size and a sharp particle size distribution. In addition, in terms of characteristics, since the packing density and coating characteristics are good and the purity is high, the resulting phosphor powder exhibits a stable and strong emission intensity, and is very useful.

[0027]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. The measuring method used in the examples was as follows. (1) Particle Shape The shape of the powder was observed with a scanning electron microscope. (2) Crystal Structure The crystal structure of the powder was identified by a powder X-ray diffractometer (MPX3, manufactured by Mac Science). C as X-ray source
u-Kα radiation was used. (3) Particle size distribution The particle size distribution of the powder was measured by a particle size distribution measuring device (COULTER LS-130 manufactured by Beckman Coulter, Inc.). (4) Fluorescence evaluation Fluorescence evaluation was measured by a fluorescence spectroscopy evaluation device (manufactured by JASCO Corporation). The excitation wavelength is 230 nm, and 300 to 780
The emission spectrum down to nm was measured. (5) Evaluation of Slow Electron Beam Emission FIG. 10 is a schematic diagram of an apparatus used for evaluation of light emission with a slow electron beam.
It was shown to. LaB ₆ filament is an electron beam source (cathode), Wehnelt cap, electron extraction electrode made of SUS-made mesh (grit), incident limiting slit (circular slit width diameter 5 mm), the phosphor coating the glass substrate (anode) Is set in a vacuum chamber.

The LaB ₆ in the filament passing a current of the direct current 2.6A, the electron extraction electrodes applying a voltage of 40V. The relationship between the anode voltage and the luminance was measured while changing the anode voltage from 0 to 1 kV. The entrance limiting slit is the same as the anode voltage. The luminance was measured from the back side of the light emitting surface using a luminance meter (Minolta nt- ／ ° P). The degree of vacuum in the vacuum chamber is 4 × 10 ^{−7 to 2} × 1
It was measured at 0 ^-6 torr. The glass substrate for phosphor application is I
A glass substrate coated with TO (tin-dissolved indium oxide) in the form of a thin film was used. A phosphor obtained by depositing a phosphor on the glass substrate in a thin film form by a sedimentation coating method was used. The coating method was such that a glass substrate was allowed to stand in distilled water, an aqueous solution in which a phosphor was dispersed was introduced therein, and the glass substrate was deposited on the glass substrate by natural sedimentation. Then, take out the substrate, after drying,
What was baked at 500 ° C. for 30 minutes was used. The coating amount of the phosphor was 2.5 mg / cm ² .

Example 1 <Synthesis of zinc gallate powder> 1500 ml of an aqueous solution of 0.05 mol / l gallium chloride was put into a three-necked round bottom flask, and ammonium sulfate was added in an amount of 2 mol per mol of Ga.
Double amount was added. The solution was heated to 70 ° C. with stirring, kept for 24 hours, and then allowed to cool to room temperature. Next, the precipitate was separated by suction filtration, and the precipitate was washed with distilled water and dried, and the gallium compound (NH ₄ Ga ₃ (S
7.6 g of O ₄ ) ₂ (OH) ₆ .H ₂ O) powder was obtained. The volume average particle diameter of the obtained gallium compound powder was 6.9 μm.

7 g of this gallium compound powder as a gallium raw material and a volume average particle diameter of 0.3 μm as a zinc raw material
The mixture was wet-mixed with 1.59 g of zinc oxide powder in ethanol in ethanol, placed in an alumina crucible, and set in a box-type electric furnace. The resultant was calcined at 1200 ° C. for 2 hours in the air to obtain 5.0 g of zinc gallate powder. X-ray diffraction confirmed a zinc gallate single phase. In addition, blue light emission was confirmed by irradiation with ultraviolet light (254 nm).

FIG. 1 shows the obtained zinc gallate (ZnG).
The results of X-ray diffraction of a ₂ O ₄ ) powder were shown. It was confirmed that it was a zinc gallate single phase. FIG. 2 shows the gallium compound (NH ₄ Ga ₃ (SO ₄ ) ₂ (O
H) ₆ · H ₂ O) showed a powder SEM photograph of. FIG. 3 shows an SEM photograph of zinc oxide powder used as a zinc raw material. FIG. 4 shows the generated zinc gallate (ZnGa ₂ O ₄ ).
An SEM photograph of the powder was shown. It was confirmed that powder of zinc gallate (ZnGa ₂ O ₄ ) in which the shape of the gallium raw material was maintained was generated. FIG. 5 shows the particle size distribution of the obtained zinc gallate (ZnGa ₂ O ₄ ) powder. The volume average particle diameter of the obtained zinc gallate powder was 4.8 μm.

Example 2 <Synthesis of Green Phosphor (ZnGa ₂ O ₄ : Mn)> Example 1
2 g of zinc gallate powder obtained in the same manner as
A 0.01 N manganese sulfate (MnSO ₄ ) solution was added to 7.1
5 ml were weighed, added and dried on an evaporator.
At this time, the addition amount of Mn was 1 mol% with respect to 1 mol of zinc gallate.

The sample was placed in an alumina boat, and H
₂ = 4% N ₂ gas while flowing at 100 ml / min.
It was baked at 1000 ° C. for 1 hour and cooled in a furnace to room temperature. Manganese-doped zinc gallate powder (ZnGa ₂ O ₄ : M
n) 1.95 g were obtained.

FIG. 6 shows an emission spectrum diagram of the obtained manganese-doped zinc gallate powder (ZnGa ₂ O ₄ : Mn) in fluorescence evaluation at an excitation light wavelength of 230 nm. A green spectrum showing a peak of emission intensity at 507 nm was observed. Table 1 shows the amount of manganese added and the intensity of the emission peak at 507 nm at an excitation light wavelength of 230 nm.

[0035]

[Table 1] Example 3 <Synthesis of Green Phosphor (ZnGa ₂ O ₄ : Mn)> 0.02
1500 ml of an aqueous 5 mol / l gallium chloride solution
Put into a round-bottom flask and add ammonium sulfate to Ga
Was added in an amount 3 times the number of moles. The solution was heated to 70 ° C. with stirring, kept for 24 hours, and then allowed to cool to room temperature. Next, the precipitate was separated by suction filtration, and the precipitate was washed with distilled water and dried, and the gallium compound (N
7.6 g of H ₄ Ga ₃ (SO ₄ ) ₂ (OH) ₆ .H ₂ O) powder was obtained. The volume average particle diameter of the obtained gallium compound powder was 2.0 μm.

This gallium compound powder is used as a gallium raw material.
7 g of powder and a volume average particle diameter of 0.3 μm as a zinc raw material
1.59 g of zinc oxide powder and 0.001N sulfuric acid
Ngan (MnSO_Four) Wet mix 25.0 ml of solution
After drying, put it in an alumina crucible and put it in a box type electric furnace.
I set it. Fired in air at 1250 ° C for 2 hours,
Gun-doped zinc gallate powder (ZnGa_TwoO_Four:
Mn) 5.0 g was obtained. Zinc gallate by X-ray diffraction
A single phase was identified. Because the emission characteristics of this green phosphor are weak
Subsequently, an activation treatment was performed. Sample in alumina boat
Put H into the tube furnace_Two= 2% N_Two100ml / mi of gas
While circulating, bake at 1000 ° C for 1 hour to room temperature
Furnace cooled. Manganese-doped zinc gallate powder
(ZnGa _TwoO_Four: Mn) 1.95 g was obtained. manganese
Was 0.1 mol%.

FIG. 7 shows an SEM photograph of the obtained manganese-doped zinc gallate powder (ZnGa ₂ O ₄ : Mn). Manganese-doped zinc gallate powder (ZnGa ₂ O ₄ : Mn) in which the shape of the gallium raw material is maintained
Was generated. Table 1 shows the amount of manganese added and the intensity of the emission peak at 507 nm when the excitation light wavelength was 230 nm.

Example 4 <Synthesis of Green Phosphor (ZnGa ₂ O ₄ : Mn)> 0.05
1500 ml of an aqueous mol / l gallium chloride solution was placed in a three-necked round bottom flask, and ammonium sulfate was added in an amount 1.5 times the number of moles of Ga. This solution was heated to 80 ° C. without stirring, kept for 12 hours, and then allowed to cool to room temperature. Next, the precipitate was separated by suction filtration, and the precipitate was washed with distilled water and dried, and the gallium compound (N
7.6 g of H ₄ Ga ₃ (SO ₄ ) ₂ (OH) ₆ .H ₂ O) powder was obtained. The volume average particle diameter of the obtained gallium compound powder was 17.5 μm.

A zinc gallate powder containing 2.5 mol% of manganese was prepared in the same manner as in Example 3.

FIG. 8 shows an SEM photograph of the obtained manganese-doped zinc gallate (ZnGa ₂ O ₄ : Mn) powder. It was confirmed that a powder of manganese-doped zinc gallate (ZnGa ₂ O ₄ : Mn) in which the shape of the gallium raw material was maintained was generated. Table 1 shows the amount of manganese added and the intensity of the emission peak at 507 nm at an excitation light wavelength of 230 nm. Manganese activation amount is 0.1mo
Strong luminescence was observed over a wide range of 1%, 1 mol%, and 2 mol%.

Example 5 <Synthesis of Green Phosphor (ZnGa ₂ O ₄ : Mn)> Example 1
Gallium compound powder (NH ₄ Ga
5 g of ₃ (SO ₄ ) ₂ (OH) ₆ .H ₂ O) was placed in an alumina crucible and fired in a box-type electric furnace at 800 ° C. for 2 hours in the air to obtain 2.6 g of gallium oxide powder. The volume average particle diameter of the gallium oxide powder was 6.2 μm.

As a gallium raw material, 2.5 g of this gallium compound powder was used, and as a zinc raw material, the volume average particle diameter was 0.1 g.
After 0.6 g of zinc oxide of 5 μm was wet-mixed in ethanol, the mixture was placed in an alumina crucible and placed in a box-type electric furnace.
The mixture was calcined at 50 ° C. for 2 hours to obtain 3.0 g of zinc gallate powder. X-ray diffraction confirmed a zinc gallate single phase.
In addition, blue light emission was confirmed by irradiation with ultraviolet light (254 nm).

The zinc gallate powder was added to 2 g in 0.01 g.
7.15 m of manganese nitrate (Mn (NO ₃ ) ₂ ) solution of N
1 was weighed out and added. At this time, the addition amount of Mn was 1 mol% with respect to 1 mol of zinc gallate. It was dried with an evaporator, placed in an alumina boat, and set in a tube furnace.

100 ml of H ₂ = 4% N ₂ gas was placed in a tube furnace.
, The temperature is raised to 900 ° C., the temperature is maintained at 900 ° C. × 1 hour, and the furnace is cooled with a gas flowing to around room temperature to obtain a green phosphor (ZnGa ₂ O ₄ : M).
1.92 g of n) were obtained.

FIG. 1 shows the results of X-ray diffraction of the obtained manganese-doped zinc gallate (ZnGa ₂ O ₄ : Mn) powder. It was confirmed that it was a zinc gallate single phase. Table 1 shows that the excitation light wavelength is 507 nm at 230 nm.
The intensity of the emission peak was shown.

Example 6 <Synthesis of Blue Phosphor (ZnGa ₂ O ₄ )> A zinc gallate powder was obtained in the same manner as in Example 1. 2 g of this zinc gallate powder was put into an alumina boat and set in a tubular furnace.

100 ml of H ₂ = 2% N ₂ gas was placed in a tube furnace.
, The temperature is raised to 1000 ° C., the temperature is maintained at 1000 ° C. × 1 hour, and the furnace is cooled with a gas flowing to around room temperature to obtain a blue phosphor (ZnGa ₂ O ₄ ).
1.90 g was obtained. In Table 1, a blue spectrum showing a peak of emission intensity at 470 nm by ultraviolet light having an excitation light wavelength of 230 nm was observed. The emission intensity was higher than in Comparative Example 2.

Comparative Example 1 <Synthesis of Green Phosphor (ZnGa ₂ O ₄ : Mn)> 5 g of commercially available gallium oxide powder reagent (volume average particle diameter 0.7 μm)
And commercially available zinc oxide reagent (volume average particle size 0.4 μm)
2.17 g was weighed and stirred and mixed in an agate mortar. This mixed powder was placed in an alumina crucible and fired at 1250 ° C. for 2 hours using a box-type electric furnace to obtain 6.9 g of zinc gallate powder.

The zinc gallate powder was added to 2 g in an amount of 0.01 g.
7.15 ml of N manganese sulfate (MnSO ₄ ) solution was weighed out and added. At this time, the addition amount of Mn was 1 mol% with respect to 1 mol of zinc gallate. The powder dried by the evaporator was put in an alumina boat and set in a tubular furnace.

100 ml of H ₂ = 4% N ₂ gas was placed in a tube furnace.
/ Min while flowing to 1000 ° C.
The temperature was kept at 0 ° C. × 1 hour, and the furnace was cooled with the gas flowing to around room temperature, and the green phosphor (ZnGa ₂ O ₄ : Mn) was 1.9.
5 g were obtained.

FIG. 9 shows an SEM photograph of the obtained manganese-doped zinc gallate (ZnGa ₂ O ₄ : Mn) powder. The obtained manganese-doped zinc gallate powder was an aggregate of fine particles having a particle diameter of 0.1 to 1 μm, and the particle shape was irregular. Table 1 shows that the excitation light wavelength =
The intensity of the emission peak at 507 nm at 230 nm was shown. The emission intensity was weaker than the sample of the example.

Comparative Example 2 <Synthesis of Blue Phosphor (ZnGa ₂ O ₄ )> In the same manner as in Comparative Example 1, 6.5 g of zinc gallate powder was obtained.

2.0 g of the zinc gallate powder was placed in an alumina boat and set in a tubular furnace. H ₂ =
While flowing 2% N ₂ gas at 100 ml / min, 1
The temperature was raised to 000 ° C., and the temperature was maintained at 1000 ° C. for 1 hour.
1.92 g of nGa ₂ O ₄ ) were obtained.

The obtained zinc gallate powder was an aggregate of fine particles having a particle diameter of 0.1 to 1 μm, and the particle shape was irregular. Excitation light wavelength = 4
A blue spectrum showing a peak of emission intensity at 70 nm was observed. The light emission intensity was lower than that of Example 6. <Slow electron beam emission evaluation> Examples 2 to 6 and Comparative Example 1
Using the phosphors of Comparative Example 2 to 2, light emission evaluation was performed using a low-speed electron beam. The evaluation conditions were as follows: the extraction voltage was 40 V, and the luminance was measured while changing the anode voltage from 0 to 1000 V. A list of these results is shown in Table 2, and these are graphed. FIG. 11 shows a green phosphor (ZnGa ₂ O ₄ : Mn).
FIG. 12 shows a blue phosphor (ZnGa ₂ O ₄ ).

Each of the phosphors of Examples 2 to 6 showed a higher emission intensity with a slow electron beam than the comparative example.

[0056]

[Table 2]

According to the present invention, it is easy to control the particle diameter and particle shape of the zinc gallate powder, and it is possible to easily provide a phosphor with high luminous efficiency and a controlled particle diameter and particle shape.

[Brief description of the drawings]

FIG. 1 shows zinc gallate (ZnGa) obtained in Example 1.
₂ is an X-ray diffraction of ₂ O ₄ ) powder and manganese-doped zinc gallate (ZnGa ₂ O ₄ : Mn) powder obtained in Example 5.

FIG. 2 is an SEM photograph of a gallium compound (NH ₄ Ga ₃ (SO ₄ ) ₂ (OH) ₆ .H ₂ O) powder used as a gallium raw material in Example 1.

FIG. 3 is an SEM photograph of zinc oxide powder used as a zinc raw material in Example 1.

FIG. 4 shows zinc gallate (ZnGa) produced in Example 1.
It is a SEM photograph of ₂ O ₄ ) powder.

FIG. 5 is a diagram illustrating the zinc gallate (ZnGa) obtained in Example 1.
₂ O ₄ ) is the particle size distribution of the powder.

FIG. 6 shows a gallium doped with manganese obtained in Example 2.
Zinc oxalate (ZnGa _TwoO_Four: Mn) Excitation light wavelength of powder =
FIG. 9 is an emission spectrum diagram in the fluorescence evaluation at 230 nm.
You.

FIG. 7 shows a gallium doped with manganese obtained in Example 3.
Zinc oxalate (ZnGa _TwoO_Four: Mn) In the SEM photograph of the powder
is there.

FIG. 8 shows a gallium doped with manganese obtained in Example 4.
Zinc oxalate (ZnGa _TwoO_Four: Mn) In the SEM photograph of the powder
is there.

FIG. 9 shows a gallium doped with manganese obtained in Comparative Example 1.
Zinc oxalate (ZnGa _TwoO_Four: Mn) In the SEM photograph of the powder
is there.

FIG. 10 is a schematic diagram of a low-speed electron beam evaluation device.

FIG. 11 shows the results of low-speed electron beam evaluation of the green phosphor (ZnGa ₂ O ₄ : Mn) in Examples 2 to 5 and Comparative Example 1.

FIG. 12 shows a blue phosphor (Z) in Example 6 and Comparative Example 2.
3 shows the results of evaluating a low-speed electron beam of nGa ₂ O ₄ ).

[Explanation of symbols] Electron gun (LaB ₆ filament) Wehnelt cap Extraction electrode (SUS mesh) Incident restriction slit Phosphor coated substrate (anode) Vacuum chamber Constant current = 2.6A Extraction voltage = 40V Anode voltage = 0 to 1kV

Claims (7)

[Claims] 1. A zinc gallate powder having an isotropic shape having a volume average particle diameter of 1 to 20 μm. 2. The method for producing zinc gallate powder according to claim 1, wherein an isotropic gallium compound powder having a volume average particle diameter of 1 to 20 μm and a zinc compound powder are mixed and fired. 3. The gallium compound powder is NH ₄ Ga.
_{3. The} method for producing zinc gallate powder according to claim 1, wherein ₃ (SO ₄ ) ₂ (OH) ₆ .H ₂ O is used. 4. The gallium compound powder includes NH ₄ Ga
_{3 (SO 4) 2 (OH} ) 6 · manufacturing method of a gallium zinc powder according to any one of claims 1 to 3 of H ₂ O is characterized by using a gallium oxide powder to be obtained by firing. 5. A zinc compound powder having a particle diameter ratio (volume average particle diameter of zinc compound powder / volume average particle diameter of gallium compound powder) of 1 or less is used. 5. The method for producing a zinc gallate powder according to any one of 4. 6. A phosphor comprising the zinc gallate powder according to any one of claims 1 to 5. 7. Manganese is added in an amount of 0.1 to 3 with respect to 1 mol of the zinc gallate powder according to any one of claims 1 to 5.
The method for producing a phosphor according to claim 6, wherein the phosphor is added by mol%.