JP2003183643A - Method of production for inorganic-fluorescent substance and inorganic-fluorescent substance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inorganic-fluorescent substance and a method of production for the same excellent in manufacturing stability without causing discoloration, uneven baking or the like in manufacturing process and having sufficient luminous properties. <P>SOLUTION: The method of production for the inorganic-fluorescent substance includes following (1) to (3) steps, and the means particle diameter of the produced inorganic-fluorescent substance is adjusted to ≤1.0 μm. Step (1), a step of producing a precursor for the inorganic-fluorescent substance by a liquid phase method; Step (2), a step of heating the precursor of the inorganic- fluorescent substance while exposing to an atmosphere including oxygen; Step (3), a step of heating the precursor of the inorganic-fluorescent substance which is heated in the step (2), while exposing to a weak reducing atmosphere. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an inorganic phosphor and a method for producing the inorganic phosphor.

[0002]

2. Description of the Related Art Conventionally, various phosphors have been used in various fields. For example, in a three-wavelength emission type fluorescent lamp which is an example of an illumination device, blue is used as the phosphor
A phosphor that emits three wavelengths of green and red is used.
Various phosphors are used in CRTs (cathode ray tubes) and PDPs (plasma display panels), which are examples of display devices, also in electroluminescence devices, active light-emitting liquid crystal devices, and radiation measurement.

In these conventionally used phosphor materials, phosphor particles having nonuniform particle sizes are used, and phosphor particles in which large, medium and small particles are mixed randomly are used. Lamps and CRTs having an average particle size in the range of 3 μm to 10 μm are used, and PDPs having an average particle size in the range of 1 μm to 5 μm are used. The aluminum-containing oxide phosphor used for the long-afterglow phosphor-containing material has an average particle size in the range of 5 μm to 50 μm.

[0004]

These conventionally used phosphors have a large particle size and have a wide particle size distribution, so that they are used in various types of plasma display devices, electroluminescent devices, active light emitting liquid crystal devices, and the like. When used for the above-mentioned application, there was a problem such as uneven light emission.

Under the circumstances as described above, in recent years, there is an increasing market need for an inorganic phosphor having a small average particle size of 1 μm or less and high emission intensity. Further, recently, there is a market need for an inorganic phosphor that is excited by light having a short wavelength of 250 nm to 430 nm and has a high emission intensity, but at present, a satisfactory level has not yet been obtained. is there.

[0006] In the conventional general method for producing an inorganic phosphor (dry mixing of raw material powders and firing with a small amount of flux), it is difficult to control each phosphor particle microscopically, resulting in a macroscopic The performance such as brightness was not sufficiently satisfactory. Further, if the phosphor is crushed in order to reduce the particle size of the phosphor, not only the luminous efficiency is lowered but also the emission intensity is lowered.

As a method for producing an inorganic phosphor for the purpose of improving various characteristics such as particle size and brightness of the phosphor, Japanese Patent Laid-Open No.
No. 2,875,551 discloses a production method including a step of mixing and adjusting a metal alkoxide in a solution state, but a more effective detailed embodiment is not disclosed. When impurities such as organic substances are mixed in the phosphor raw material mixture when firing the phosphor raw material mixture, they cannot be burned sufficiently and the phosphor is discolored, the emission intensity is lowered, or firing unevenness occurs. There was a problem such as doing.

The present invention solves the problems in the prior art and achieves the following objects. That is, it is an object of the present invention to provide an inorganic phosphor having excellent production stability without causing discoloration, firing unevenness and the like in the production process, and a method for producing the same.

[0009]

The above object of the present invention is achieved by the following constitution.

1. A method for producing an inorganic phosphor, comprising the steps (1) to (3), wherein the average particle size of the obtained inorganic phosphor is adjusted to 1.0 μm or less. Production method.

2. It is a manufacturing method of the inorganic fluorescent substance which has said process (1)-(3), Comprising: The excitation wavelength of an inorganic fluorescent substance is 250 nm-430 nm, The manufacturing method of the inorganic fluorescent substance characterized by the above-mentioned.

3. 3. The method for producing an inorganic phosphor as described in 1 or 2 above, wherein a sol-gel method is used as the liquid phase method.

4. 3. The method for producing an inorganic phosphor as described in 1 or 2 above, wherein a crystallization method is used as the liquid phase method.

5. The process of heating the inorganic phosphor precursor while exposing it to an atmosphere having oxygen is 600 ° C. or higher and 1000
5. The method for producing an inorganic phosphor according to any one of 1 to 4 above, wherein the temperature is not higher than ° C.

6. 6. The method for producing an inorganic phosphor according to any one of 1 to 5 above, wherein the step of heating the inorganic phosphor precursor while exposing it to an atmosphere containing oxygen is 30 minutes or more and 90 minutes or less.

7. An oxygen-containing atmosphere has an oxygen concentration of 1
% Or more and 50% or less, The manufacturing method of the inorganic fluorescent substance in any one of said 1-6 characterized by the above-mentioned.

8. The process of heating the inorganic phosphor precursor while exposing it to a weak reducing atmosphere is 1000 ° C. or higher and 1800 ° C.
The method for producing an inorganic phosphor according to any one of 1 to 7 above, wherein the method is as follows.

9. The weak reducing atmosphere has an oxygen concentration of 0 or more and 100 ppm or less, The method for producing an inorganic phosphor according to any one of 1 to 8 above.

10. The weakly reducing atmosphere has a hydrogen concentration of 0.
1 to 9 which is 1% or more and 10% or less
The method for producing the inorganic phosphor according to any one of 1.

11. In the step of heating while exposing to an atmosphere containing oxygen and the step of heating while exposing to a weakly reducing atmosphere, the atmosphere gas is 0.1 liter / min or more 10
11. The method for producing an inorganic phosphor according to any one of 1 to 10 above, wherein the inorganic phosphor is circulated at a flow rate of liter / minute or less.

12. After the step of heating while exposing to an atmosphere containing oxygen, a vacuum state of 1.33 × 10 ³ Pa or less is applied, and then the atmosphere is replaced with a weak reducing atmosphere. Of the method for producing an inorganic phosphor.

13. 13. The method for producing an inorganic phosphor according to any one of 1 to 12 above, wherein the inorganic phosphor contains Ba, Mg, Al and an activator.

14. 13. The method for producing an inorganic phosphor according to any one of 1 to 12 above, wherein the inorganic phosphor contains Ba, Si and an activator.

15. 13. The method for producing an inorganic phosphor according to any one of 1 to 12 above, wherein the inorganic phosphor contains Y, V and an activator.

16. 13. The method for producing an inorganic phosphor according to any one of 1 to 12 above, wherein the inorganic phosphor contains Sr, P, Cl and an activator.

17. The inorganic phosphor is Ba, Ca, Mg,
1 characterized by containing P, Cl and an activator
13. The method for producing an inorganic phosphor according to any one of 1 to 12.

18. 13. The method for producing an inorganic phosphor according to any one of 1 to 12 above, wherein the inorganic phosphor contains Sr, Mg, P and an activator.

19. An inorganic phosphor obtained by the method for producing an inorganic phosphor according to any one of 1 to 18 above.

The present invention will be described in detail below. << Inorganic Phosphor >> The “inorganic phosphor having an average particle diameter of 1.0 μm or less (also referred to as the inorganic phosphor of the present invention)” of the present invention will be described.

The method for producing an inorganic phosphor of the present invention according to claim 1 is characterized by producing an inorganic phosphor having a high emission intensity while having a small average particle size of 1.0 μm or less. is there.

The average particle diameter of the inorganic phosphor is preferably 0.8 μm or less, more preferably 0.1 to 0.6 μm.

The above "average particle size" is the sphere-converted particle size,
The sphere-converted particle size is a particle size represented by the particle size of the sphere, assuming a sphere having the same volume as the volume of the particle. Here, the particle size of the inorganic phosphor of the present invention can be measured using a transmission electron microscope (TEM) or a scanning electron microscope (SEM).

It is preferable that particles having a particle diameter of 1.0 μm or less account for 50% or more of the total particles by mass, and most preferably 70% or more of the total particles.

Further, the variation coefficient of the particle size distribution of particles having an average particle diameter of 1.0 μm or less is preferably 50% or less, and most preferably 30% or less.

The coefficient of variation of particle size distribution (width of particle distribution) is a value defined by the following equation.

Coefficient of variation of particle size distribution (width of particle distribution)
[%] = (Standard deviation of particle diameter / average particle diameter) × 100 The “inorganic phosphor having an excitation wavelength of 250 nm or more and 430 nm or less” of the present invention will be described.

The inorganic phosphor according to claim 2 has a thickness of 250 nm.
Although it has an excitation wavelength of ˜430 nm, the excitation wavelength range is preferably from the ultraviolet region to the visible region of short wavelength, more preferably 300 nm to 400 nm. The measurement of the excitation wavelength can be easily measured by a commercially available spectrofluorometer capable of scanning the excitation wavelength and the fluorescence wavelength, respectively.

The inorganic phosphors according to claims 13 to 18 are preferably used as the inorganic phosphor according to the present invention.

The inorganic phosphor containing Ba, Mg, Al and the activator of the present invention will be described. Ba, M of the present invention
The composition of the inorganic phosphor containing g, Al and an activator is B
Other than a, Mg, and Al, there is no particular limitation, but the metal oxide represented by BaMgAl ₁₀ O ₁₇ which is a crystal matrix is C
e, Pr, Nd, Pm, Sm, Eu, Gd, Tb, D
A combination of rare earth metal ions such as y, Ho, Er, Tm, and Yb and metal ions such as Ag, Al, Mn, Sb, and Sn as an activator or coactivator is preferable.

The inorganic phosphor containing Ba, Si and the activator of the present invention will be described. The composition of the inorganic phosphor containing Ba, Si and the activator of the present invention is other than Ba and Si,
Although not particularly limited, metal oxides represented by Ba ₂ SiO ₄ , which is a crystal matrix, include Ce, Pr, Nd, Pm, and Sm.
A combination of rare earth metal ions such as Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb and metal ions such as Ag, Al, Mn, Sb, and Sn as an activator or coactivator is preferable.

The inorganic phosphor containing Y, V and the activator of the present invention will be described. The composition of the inorganic phosphor containing Y, V and an activator of the present invention is not particularly limited except Y and V, but the metal oxides represented by YVO ₄ which is a crystal matrix are Ce, Pr, Nd, Pm, Sm, Eu, Gd, T
A combination of rare earth metal ions such as b, Dy, Ho, Er, Tm, and Yb and metal ions such as Ag, Al, Mn, Sb, and Sn as an activator or coactivator is preferable.

The inorganic phosphor containing Sr, P, Cl and the activator of the present invention will be described. Sr, P of the present invention,
The composition of the inorganic phosphor containing Cl and the activator is Sr,
Other than P and Cl, there is no particular limitation, but Sr which is a crystal matrix
Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, and D are included in halophosphate compounds represented by ₁₀ (PO ₄ ) ₆ Cl _{2 and the} like.
A combination of rare earth metal ions such as y, Ho, Er, Tm, and Yb and metal ions such as Ag, Al, Mn, Sb, and Sn as an activator or coactivator is preferable.

The inorganic phosphor containing Ba, Ca, Mg, P, Cl and the activator of the present invention will be described. The composition of the inorganic phosphor containing Ba, Ca, Mg, P, Cl and the activator of the present invention is not particularly limited except Ba, Ca, Mg, P, Cl, but it is a crystal matrix (Ba, Ca, Mg)
Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, and D are included in halophosphate compounds represented by ₁₀ (PO ₄ ) ₆ Cl _{2 and the} like.
A combination of rare earth metal ions such as y, Ho, Er, Tm, and Yb and metal ions such as Ag, Al, Mn, Sb, and Sn as an activator or coactivator is preferable.

The inorganic phosphor containing Sr, Mg, P and the activator of the present invention will be described. Sr, M of the present invention
The composition of the inorganic phosphor containing g, P and an activator is Sr,
Other than Mg and P, there is no particular limitation, but it is a crystal matrix (S
Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, D are included in phosphoric acid compounds represented by r, Mg) ₃ (PO ₄ ) _{2 and the} like.
A combination of rare earth metal ions such as y, Ho, Er, Tm, and Yb and metal ions such as Ag, Al, Mn, Sb, and Sn as an activator or coactivator is preferable.
<< Method of Manufacturing Inorganic Phosphor >> The method of manufacturing the inorganic phosphor of the present invention will be described.

The method for producing an inorganic phosphor of the present invention has at least the following three steps as described in claim 1 or 2. Step (1) A step of producing a precursor of an inorganic phosphor by a liquid phase method. Step (2) A step of heating the inorganic phosphor precursor while exposing it to an atmosphere containing oxygen. Step (3) A step of heating the heated inorganic phosphor precursor while exposing it to a weak reducing atmosphere after the step (3).

In the above step (1), the inorganic phosphor precursor is an inorganic phosphor raw material mixture before firing, and one of the features of the manufacturing method of the present invention is that the inorganic phosphor precursor is liquid. It is prepared by the phase method. (Liquid phase method) The production of the precursor of the inorganic phosphor of the present invention by the liquid phase method will be described.

As the liquid phase method in the present invention, a general method such as a sol-gel method or a crystallization method can be used.

Production of Inorganic Phosphor Precursor by Sol-Gel Method
The method generally refers to the matrix, activator or co-activator
Element (metal), for example, Si (OCH₃)_FourAnd Eu³⁺
(CH₃COCHCOCH₃)₃Metal alkoxides such as
Add simple metal to metal complex or their organic solvent solution
Make double alkoxide (eg Al (OC_FourH₉) ₃
Made by adding metallic magnesium to 2-butanol solution
Mg [Al (OC_FourH₉)₃]₂Etc.), metal halides,
Mix the required amount of metal salt of organic acid or metal as a simple substance, and
Means a production method by chemical polycondensation.

The method of producing an inorganic phosphor precursor by the crystallization method is to change the physical or chemical environment by cooling, evaporation, pH adjustment, concentration, etc., or to change the state of the mixed system by a chemical reaction. When it occurs, a solid phase may precipitate from the liquid phase, and it is generally said to be a crystallization phenomenon, but a production method by physical or chemical operation that can cause such a crystallization phenomenon to occur. Means (Baking Step) The heating step (hereinafter, also referred to as “baking step”) in the present invention will be described.

The firing step of the present invention is a step of firing the inorganic phosphor precursor to obtain a fired product (inorganic phosphor).

In the method for producing an inorganic phosphor of the present invention, it is preferable that, in the firing step, after the furnace core of the firing furnace is replaced with an atmosphere containing oxygen, heating is performed at 600 ° C. or higher and 1000 ° C. or lower. More preferably, the temperature is not lower than 800 ° C and not higher than 800 ° C. Also, at 600 ° C or higher and 1000 ° C or lower for 30 minutes or longer 9
It is preferable to hold for 0 minutes or less, but for 30 minutes or more 6
It is more preferably 0 minutes or less.

The oxygen-containing atmosphere preferably has an oxygen concentration of 1% or more and 50% or less, more preferably 10% or more and 30% or less. By heating in an atmosphere containing oxygen in this way, impurities such as organic substances and byproducts remaining in the inorganic phosphor precursor can be removed, and discoloration of the phosphor can be prevented and good emission characteristics can be obtained. be able to.

After the heating was started, the atmospheric gas in the furnace core was 0.
It is preferable to flow at a flow rate of 1 liter / min or more and 10 liter / min or less, but 0.5 liter / m
It is more preferably in or more and 2.0 liters / min or less.
As a result, the atmosphere in the furnace core is replaced, and impurities, by-products, etc. other than the inorganic phosphor can be discharged from the furnace core.

After maintaining the state of being heated in an atmosphere containing oxygen, substituting the atmosphere with a weak reducing atmosphere, it is preferable to heat to 1000 ° C. or higher and 1800 ° C. or lower.
It is more preferable to set the temperature to a constant temperature in the range from ℃ to 1600 ℃. The heating time is preferably 0.5 to 6 hours, more preferably 1 to 3 hours.

The weak reducing atmosphere preferably has an oxygen concentration of 100 ppm or less, more preferably 10 ppm or less.

A mixed gas having a hydrogen concentration of 0.1% or more and 10% or less and the remaining component being nitrogen is preferable, and a mixed gas having a hydrogen concentration of 0.1% or more and 5% or less and the remaining component being nitrogen. More preferable. When the hydrogen concentration is 0.1% or more, the emission characteristics can be improved, and when it is 5% or less, it is preferable in handling.

When the atmosphere in the furnace core is replaced with an atmosphere containing oxygen by a weak reducing atmosphere, the inside of the furnace core is 1.33%.
It is preferable to apply a vacuum of 10 ³ Pa or less. A rotary pump or the like can be used for vacuum suction. When the inside of the furnace core is evacuated, there is an advantage that the efficiency of atmosphere replacement is increased. In the case of so-called purge replacement in which the atmosphere is replaced without passing through a vacuum, it is necessary to inject an atmosphere having a volume of at least 3 times the volume of the furnace core.

[0058]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples.

Example 1 1. Production Formula of Inorganic Phosphor (Phosphor 1-1) Composition formula: Ba ₂ SiO ₄ : Eu ^{2+ An} inorganic phosphor precursor was produced by the following sol-gel method.

4 × 10 ^-2 mol of Si (OC ₂ H ₅ ) ₄ and 2
× 10 ^-4 mol of _{Eu (CH 3 COCHCOCH 3) 3} · 2
H ₂ O was dissolved in 150 ml of ethanol, and this was added dropwise to water (150 ml) -ethanol (150 ml) to which 1.6 × 10 ⁻² mol of ammonia was added at a rate of about 1 ml / min with stirring to obtain a sol. It was adjusted. The obtained sol was concentrated with an evaporator so that the concentration was about 15 times, and
295 ml of a 3 mol / L barium nitrate aqueous solution was added to cause gelation to obtain a wet gel. The obtained wet gel was aged at 60 ° C. for 15 hours in a closed container.

Then, the ethanol (3
00 ml) at an addition rate of 1 ml / min,
The deposited inorganic phosphor precursor is filtered and separated, and the mixture is heated at 50 ° C. for 10 minutes.
Dried for hours.

The inorganic phosphor precursor is filled in a quartz glass boat which is a firing container, and in a firing furnace in which an atmosphere containing oxygen (oxygen concentration 20%) flows at a flow rate of 1.0 liter / min. After heating at 600 ° C. for 30 minutes (heating step in an aerobic atmosphere), the atmosphere is changed to 6.65 × 10 ² Pa
Then, the atmosphere was replaced with an atmosphere (oxygen concentration of 100 ppm or less) in which 5% H ₂ -95% N ₂ gas was flowing at a flow rate of 1.0 liter / min, and heat treatment was performed at 1050 ° C. for 3 hours. gave. After firing, after cooling to 200 ° C. or lower, the fired product was taken out into the atmosphere, and the composition formula: Ba ₂ Si was used.
An inorganic phosphor of O ₄ : Eu ²⁺ was obtained (phosphor 1-1).

The average particle size of the obtained phosphor is 0.78 μm.
m, maximum excitation wavelength 350 nm, maximum emission wavelength 501 nm
Met. The size of the phosphor particles was measured by a transmission electron microscope and a scanning electron microscope. 2. Manufacturing method of inorganic phosphor (comparative phosphor 1-2): In manufacturing Ba ₂ SiO ₄ : Eu ²⁺ phosphor 1-1, the inorganic phosphor precursor is not subjected to a heating step in an oxygen-containing atmosphere. , In an atmosphere in which 5% H ₂ -95% N ₂ gas is flowing at a flow rate of 1.0 liter / min (oxygen concentration 100 ppm or less), from room temperature to 1
A composition formula: Ba ₂ Si was used in the same manner as the phosphor 1-1 except that the phosphor was heated to 050 ° C. and heat-treated at the same temperature for 3 hours.
An inorganic phosphor of O ₄ : Eu ²⁺ was obtained (comparative phosphor 1-
2).

The average particle size of the obtained phosphor is 1.12 μm.
m, maximum excitation wavelength 350 nm, maximum emission wavelength 501 nm
Met.

The obtained phosphor 1-1 and comparative phosphor 1-2
The sample was irradiated with ultraviolet rays having an excitation wavelength of 350 nm, and the emission intensity was measured. The obtained result is the emission intensity of the phosphor 1-1 of 10
The relative intensity is set to 0 and shown in Table 1, and the appearance color of the phosphor is also shown in Table 1.

[0066]

[Table 1]

As is clear from Table 1, the obtained phosphor 1-1 has an average particle size of about 30% as compared with the comparative phosphor 1-2.
It can be seen that the emission intensity is extremely high and there is no discoloration of the phosphor even though it is small. However, the comparative phosphor 1-2 obtained without passing through the heating step in an aerobic atmosphere not only has insufficient emission intensity but also changes its color to brown.
It turns out that it is not suitable for practical use. This discoloration is a failure due to organic substances remaining in the phosphor because heating was not performed in an oxygen-containing atmosphere.

Example 2 1. Production Formula of Inorganic Phosphor (Phosphor 2-1) Composition formula: BaMgAl ₁₀ O ₁₇ : Eu ^{2+ An} inorganic phosphor precursor was produced by the following sol-gel method.

2.8 × 10 ^-2 mol of Al (OC ₄ H ₉ ) ₄
When 8.3 × 10 ^-3 mol of Mg (NO ₃₎ solution of ₂ · 6H ₂ O was dissolved in ethanol 333ml, 2.8 × 10 ^-2 mol of Al (OC ₄ H _{9) 4} and 1.5 × 10 ^-3 mol of Eu
_{(CH 3 COCHCOCH 3) 3 ·} 2H 2 O in ethanol 3
Solution dissolved in 33 ml and 2.8 × 10 ^-2 mol of Al
A solution of (OC ₄ H ₉ ) ₄ and 8.3 × 10 ⁻³ mol of Ba dissolved in 333 ml of ethanol was mixed at 70 ° C. and stirred for 30 minutes, and 250 ml of water was added to cause gelation to obtain a wet gel. . The obtained wet gel was aged at 60 ° C. for 15 hours in a closed container. Then, the deposited inorganic phosphor precursor was collected by filtration and dried at 50 ° C. for 10 hours.

The inorganic phosphor precursor was filled in a boat made of alumina, which is a firing container, and was placed in a firing furnace in which an atmosphere gas containing oxygen was passed at a flow rate of 2.0 liter / min.
Heating at 00 ° C for 60 minutes (heating process in aerobic atmosphere)
After that, the atmosphere was set to a vacuum state of 1.33 × 10 ² Pa, and then 5% H ₂ -95% at a flow rate of 1.0 liter / min.
Replaced with an atmosphere in which N ₂ gas is flowing, 1400 ° C.
Was heat-treated for 3 hours. After firing, after cooling to 200 ° C. or lower, the fired product was taken out into the air, and the composition formula: Ba
An inorganic phosphor of MgAl ₁₀ O ₁₇ : Eu ²⁺ was obtained (phosphor 2
-1).

The average particle size of the obtained phosphor is 0.91 μm.
m, maximum excitation wavelength 233 nm, maximum emission wavelength 447 nm
Met. 2. Production of Inorganic Phosphor (Comparative Phosphor 2-2) Composition formula: BaMgAl_TenO₁₇: Eu²⁺ In the production of the phosphor 2-1, the inorganic phosphor precursor is acidified.
1.0 liter without going through the heating process in an elementary atmosphere
5% H at a flow rate of / min₂-95% N₂Gas is in circulation
In an atmosphere that heats from room temperature to 1400 ° C at the same temperature
Same as Phosphor 2-1 except heat treated for 3 hours.
And composition formula: BaMgAl_TenO₁₇: Eu ²⁺Inorganic phosphor
Was obtained (Comparative Phosphor 2-2).

The average particle size of the obtained phosphor is 1.36 μ.
m, maximum excitation wavelength 233 nm, maximum emission wavelength 447 nm
Met.

Obtained phosphor 2-1 and comparative phosphor 2-2
Was irradiated with ultraviolet rays having an excitation wavelength of 233 nm, and the emission intensity was measured. The obtained result is the emission intensity of the phosphor 2-1 of 10
The relative intensity is set to 0 and is shown in Table 2, and the appearance color of the phosphor is also shown in Table 2.

[0074]

[Table 2]

As is clear from Table 2, the phosphor 2-1 shows high emission intensity and discolors the phosphor, even though the average particle size is about 33% smaller than that of the comparative phosphor 2-2. It turns out that there is nothing. However, it can be seen that the comparative phosphor 2-2 obtained without the heating step in the aerobic atmosphere is not suitable for practical use because it not only has a reduced emission intensity but also has a light brown discoloration. This discoloration is a failure due to organic substances remaining in the phosphor because heating was not performed in an oxygen-containing atmosphere.

Example 3 1. Inorganic phosphor (phosphor 3-1) of manufacturing the composition formula: YVO _4: Eu ³⁺ below, were prepared inorganic phosphor precursor by sol gel method.

1.6 × 10 ^-2 mol of Y (CH ₃ COCH
COCH _{3) 3} · 3H ₂ O and 8.7 × 10 ^-4 mol of Eu
_{(CH 3 COCHCOCH 3) 3 ·} 2H 2 O in ethanol 1
Solution dissolved in 40 ml and 1.8 × 10 ^-2 mol VO
(CH ₃ COCHCOCH ₃ ) ₂ in 175 ml of methanol
The solution dissolved in was mixed at 60 ° C and stirred for 30 minutes, then water 14
7 ml was added at a rate of 5 ml / min for gelation to obtain a wet gel.

The obtained wet gel was aged at 60 ° C. for 15 hours in a closed container. Then, the deposited inorganic phosphor precursor was collected by filtration and dried at 50 ° C. for 10 hours.

The inorganic phosphor precursor was filled in a quartz glass boat, which is a firing container, and the atmosphere gas containing oxygen was passed at a flow rate of 1.0 liter / min in a firing furnace.
Heating at 700 ° C for 40 minutes (heating process in an aerobic atmosphere)
Then, 0.1% H ₂ -9 at a flow rate of 0.1 liter / min.
Replace with an atmosphere in which 9.9% N ₂ gas is flowing and
Heat treatment was performed at 050 ° C. for 3 hours. After firing, 200 ℃
After cooling to below, the fired product was taken out into the atmosphere, the composition formula: YVO _4: to obtain an inorganic phosphor Eu ³⁺ (phosphor 3
1).

The average particle size of the obtained phosphor is 0.68 μm.
m, maximum excitation wavelength 310 nm, maximum emission wavelength 619 nm
Met. 2. Production of Inorganic Phosphor (Comparative Phosphor 3-2) Compositional formula: YVO ₄ : Eu ^{3+ In} the production of the phosphor 3-1, the inorganic phosphor precursor is not subjected to a heating step in an aerobic atmosphere, Heating from room temperature to 1050 ° C. in an atmosphere in which 0.1% H ₂ -99.9% N ₂ gas is flowing at a flow rate of 1 liter / min,
An inorganic phosphor of the composition formula: YVO ₄ : Eu ³⁺ was obtained in the same manner as phosphor 3-1 except that heat treatment was performed at the same temperature for 3 hours (comparative phosphor 3-2).

The average particle size of the obtained phosphor is 1.02 μm.
m, maximum excitation wavelength 310 nm, maximum emission wavelength 619 nm
Met.

Obtained phosphor 3-1 and comparative phosphor 3-2
The sample was irradiated with ultraviolet light having an excitation wavelength of 310 nm and the emission intensity was measured. The obtained result is the emission intensity of the phosphor 3-1 of 10
The relative intensity is set to 0 and shown in Table 3, and the appearance color of the phosphor is also shown in Table 3.

[0083]

[Table 3]

As is clear from Table 3, the phosphor 3-1 shows a high emission intensity and has a high emission intensity even though the average particle size is smaller by about 33% than the comparative phosphor 3-2. It turns out that there is no discoloration. However, it can be seen that the comparative phosphor 3-2 obtained without the heating step in the aerobic atmosphere is not suitable for practical use because it not only has insufficient emission intensity but also changes its color to light brown. This discoloration is a failure due to organic substances remaining in the phosphor because heating was not performed in an oxygen-containing atmosphere.

Example 4 1. Composition formula of inorganic phosphor (phosphor 4-1): (Ba, Ca, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : E
u ^{2+ An} inorganic phosphor precursor was manufactured by the following crystallization method.

0.38 mol of BaCl ₂ , 0.17 mol of CaCl ₂ , 5.6 × 10 ^-2 mol of MgNO ₃ .6H ₂
O, 5.6 × 10 ^-3 mol of _{Eu (NO 3) 3 · 6H} 2 O,
0.34 mol of KH ₂ (PO) ₄ was dissolved in 500 ml of pure water and mixed at 60 ° C. At that time, aqueous ammonia was added so as to maintain pH 9 of the mixed solution. A precipitate was formed simultaneously with the mixing, and the obtained precipitate was collected by filtration and dried at 50 ° C. for 10 hours to produce a crystalline inorganic phosphor precursor.

The inorganic phosphor precursor is quartz, which is a firing container.
Fill a glass boat with a flow of 1.0 liter / min
In a firing furnace in which an atmospheric gas containing oxygen in a quantity is flowing,
Heating at 600 ℃ for 30 minutes (heating process in an aerobic atmosphere)
After that, change the atmosphere to 6.65 × 10 ²As a vacuum state of Pa
5% H at a flow rate of 1.0 liter / min₂-95%
N₂Replace with atmosphere in which gas is flowing and 1050 ℃
Was heat-treated for 3 hours. After firing, up to 200 ℃
After cooling, the fired product was taken out into the atmosphere and the composition formula: (B
a, Ca, Mg)_Ten(PO_Four)₆Cl₂: Eu²⁺Inorganic firefly
A light body was obtained (phosphor 4-1).

The average particle size of the obtained phosphor is 0.43 μm.
m, maximum excitation wavelength 360 nm, maximum emission wavelength 495 nm
Met. 2. Composition formula of inorganic phosphor (comparative phosphor 4-2): (Ba, Ca, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : E
In the production of the u ²⁺ phosphor 4-1, 5% H ₂ -95% N ₂ gas is supplied at a flow rate of 1.0 liter / min without going through the heating step of the inorganic phosphor precursor in an oxygen-containing atmosphere. In the flowing atmosphere, the composition formula: (Ba, Ca, Mg) ₁₀ (PO 4) was used in the same manner as the phosphor 4-1 except that it was heated from room temperature to 1050 ° C. and heat-treated at the same temperature for 3 hours. ₄ ) ₆ C
An inorganic phosphor of l ₂ : Eu ²⁺ was obtained (comparative phosphor 4-
2).

The average particle size of the obtained phosphor is 1.01 μm.
m, maximum excitation wavelength 360 nm, maximum emission wavelength 495 nm
Met.

Obtained phosphor 4-1 and comparative phosphor 4-2
Was irradiated with ultraviolet rays having an excitation wavelength of 360 nm, and the emission intensity was measured. The obtained result is the emission intensity of phosphor 4-1 of 10
Table 4 shows the relative intensity as 0, and Table 4 also shows the appearance color of the phosphor.

[0091]

[Table 4]

As is clear from Table 4, the phosphor 4-1 exhibits high emission intensity even though the average particle size is about 57% smaller than that of the comparative phosphor 4-2, and the discoloration of the phosphor also occurs. I know there isn't. However, it is understood that the comparative phosphor 4-2 obtained without passing through the heating step in the aerobic atmosphere is not suitable for practical use because not only the emission intensity is lowered but also the color is changed to pale yellow.

Example 5 1. Production Formula of Inorganic Phosphor (Phosphor 5-1) Composition Formula: Sr ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ^{2+ An} inorganic phosphor precursor was produced by the following crystallization method.

0.56 mol of SrCl ₂ .6H ₂ O, 5.
6 × 10 ⁻³ mol of Eu (NO ₃ ) ₃ · 6H ₂ O, 0.34
Dissolve each mole of KH ₂ (PO) ₄ in 500 ml of pure water,
Mixed at 60 ° C. At that time, aqueous ammonia was added so as to maintain pH 9 of the mixed solution. Precipitation occurs at the same time as mixing,
The obtained crystal precipitate was collected by filtration and dried at 50 ° C. for 10 hours to obtain a crystalline inorganic phosphor precursor.

The inorganic phosphor precursor is quartz, which is a firing container.
Fill a glass boat with a flow of 1.0 liter / min
In a firing furnace in which an atmospheric gas containing oxygen in a quantity is flowing,
Heating at 600 ℃ for 30 minutes (heating process in an aerobic atmosphere)
After that, change the atmosphere to 6.65 × 10 ²As a vacuum state of Pa
5% H at a flow rate of 1.0 liter / min₂-95%
N₂Replace with atmosphere in which gas is flowing and 1050 ℃
Was heat-treated for 3 hours. After firing, up to 200 ℃
After cooling, the fired product was taken out into the air, and the composition formula: Sr
_Ten(PO_Four)₆Cl₂: Eu²⁺We obtained an inorganic phosphor of
Body 5-1).

The average particle size of the obtained phosphor is 0.47 μm.
m, maximum excitation wavelength 283 nm, maximum emission wavelength 447 nm
Met. 2. Production Formula of Inorganic Phosphor (Comparative Phosphor 5-2) Composition Formula: Sr ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ^{2+ In} the production of the phosphor 5-1, the inorganic phosphor precursor is heated in an oxygen-containing atmosphere. Without passing through the steps, heating is performed from room temperature to 1050 ° C. in an atmosphere in which 5% H ₂ -95% N ₂ gas is flowing at a flow rate of 1.0 liter / min, and heat treatment is performed at the same temperature for 3 hours. An inorganic phosphor of the composition formula: Sr ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ was obtained in the same manner as phosphor 5-1 except for the above (Comparative phosphor 5-2).

The average particle size of the obtained phosphor is 1.05 μm.
m, maximum excitation wavelength 283 nm, maximum emission wavelength 447 nm
Met.

Obtained phosphor 5-1 and comparative phosphor 5-2
Was irradiated with ultraviolet rays having an excitation wavelength of 283 nm, and the emission intensity was measured. The obtained result is the emission intensity of the phosphor 5-1 of 10
The relative intensity is set to 0 and shown in Table 5, and the appearance color of the phosphor is also shown in Table 5.

[0099]

[Table 5]

As is clear from Table 5, the phosphor 5-1 exhibits a high emission intensity even though the average particle size is about 55% smaller than that of the comparative phosphor 5-2, and the discoloration of the phosphor also occurs. I know there isn't. However, it is understood that the comparative phosphor 5-2 obtained without the heating step in the aerobic atmosphere is not suitable for practical use because the emission intensity is lowered and the color is changed to pale yellow.

Example 6 1. Inorganic phosphor (phosphor 6-1) of manufacturing _{formula: (Sr, Mg) 3 (} PO 4) 2: Sn 2+ below, were prepared inorganic phosphor precursor at crystallization.

0.45 mol of SrCl ₂ .6H ₂ O, 5.
6 × 10 ^-2 mol of MgNO ₃ .6H ₂ O, 8.4 × 10 ^-3
Mol SnCl ₂ , 0.34 mol KH ₂ (PO) ₄ ,
Each was dissolved in 500 ml of pure water and mixed at 60 ° C. At that time, aqueous ammonia was added so as to maintain pH 9 of the mixed solution. A precipitate was formed simultaneously with the mixing, and the obtained precipitate was collected by filtration and dried at 50 ° C. for 10 hours to obtain a crystalline inorganic phosphor precursor.

The inorganic phosphor precursor is quartz, which is a firing container.
Fill a glass boat with a flow of 1.0 liter / min
In a firing furnace in which an atmospheric gas containing oxygen in a quantity is flowing,
Heating at 600 ℃ for 30 minutes (heating process in an aerobic atmosphere)
After that, change the atmosphere to 6.65 × 10 ²As a vacuum state of Pa
2% H at a flow rate of 1.0 liter / min₂-98%
N₂Replace with atmosphere in which gas is flowing and 1050 ℃
Was heat-treated for 3 hours. After firing, up to 200 ℃
After cooling, the fired product was taken out into the atmosphere, and the composition formula: (S
r, Mg)₃(PO_Four)₂: Sn²⁺Obtained an inorganic phosphor of
(Phosphor 6-1).

The average particle size of the obtained phosphor is 0.59 μm.
m, maximum excitation wavelength 255 nm, maximum emission wavelength 620 nm
Met. 2. Production of inorganic phosphor (phosphor 6-2) Composition formula: (Sr, Mg)₃(PO_Four)₂: Sn²⁺ In the production of the phosphor 6-1, the inorganic phosphor precursor is acidified.
1.0 liter without going through the heating process in an elementary atmosphere
2% H at a flow rate of / min₂-98% N₂Gas is in circulation
In an atmosphere that heats from room temperature to 1050 ℃, at the same temperature
Same as phosphor 6-1 except heat treatment for 3 hours
And compositional formula: (Sr, Mg)₃(PO_Four) ₂: Sn²⁺Nothing
An organic phosphor was obtained (Comparative phosphor 6-2).

The average particle size of the obtained phosphor is 1.08 μm.
m, maximum excitation wavelength 255 nm, maximum emission wavelength 620 nm
Met.

Obtained phosphor 6-1 and comparative phosphor 6-2
Was irradiated with ultraviolet rays having an excitation wavelength of 255 nm, and the emission intensity was measured. The obtained result is the emission intensity of the phosphor 6-1 of 10
Table 6 shows the relative intensity as 0, and Table 6 also shows the appearance color of the phosphor.

[0107]

[Table 6]

As is clear from Table 6, the phosphor 6-1 exhibits a high emission intensity even though the average particle size is smaller by about 45% than the comparative phosphor 6-2, and the discoloration of the phosphor also occurs. I know there isn't. However, it is understood that the comparative phosphor 6-2 obtained without the heating step in the aerobic atmosphere is not suitable for practical use because the emission intensity is reduced and the color is changed to brown.

[0109]

EFFECTS OF THE INVENTION According to the present invention, it is possible to obtain a remarkably excellent effect that an inorganic phosphor having excellent emission stability and excellent production stability can be obtained without causing discoloration or firing unevenness in the production process. ing.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C01G 31/00 C01G 31/00 C09K 11/59 CPM C09K 11/59 CPM CPR CPR CPW CPW CPX CPX CQA CQA 11 / 64 11/64 11/71 11/71 11/73 11/73 11/82 11/82 (72) Inventor Takahiro Okada In-house (72) Inventor Hideki Hoshino, 1st Sakura-cho, Hino City, Tokyo Konica Stock Company, 1 Sakura-cho, Hino-shi, Tokyo In-house (72) Inventor Tokiko Hoshino Konica Stock Company, 1-sakura-cho, Hino-shi, Tokyo Internal F-term (reference) 4G048 AA03 AB02 AC08 AD03 AE05 4G073 BA13 BD20 CC20 FC01 FC06 FD12 UB37 4G076 AA02 AA18 AA22 AB07 AB13 BA13 BA14 BA23 CA02 DA15 4H001 CA04 CA06 CF02 XA08 XA12 XA13 XA14 XA15 XA17 XA20 XA23 XA38 XA39 XA56 YA50 YA63

Claims (19)

[Claims] 1. A method for producing an inorganic phosphor comprising the following steps (1) to (3), wherein the average particle size of the obtained inorganic phosphor is adjusted to 1.0 μm or less. A method for producing an inorganic phosphor. Step (1) A step of producing a precursor of an inorganic phosphor by a liquid phase method. Step (2) A step of heating the inorganic phosphor precursor while exposing it to an atmosphere containing oxygen. Step (3) A step of heating the heated inorganic phosphor precursor while exposing it to a weak reducing atmosphere after the step (3). 2. A method for producing an inorganic phosphor having the following steps (1) to (3), wherein the excitation wavelength of the inorganic phosphor is 250 nm to 430 nm. Production method. Step (1) A step of producing a precursor of an inorganic phosphor by a liquid phase method. Step (2) A step of heating the inorganic phosphor precursor while exposing it to an atmosphere containing oxygen. Step (3) A step of heating the heated inorganic phosphor precursor while exposing it to a weak reducing atmosphere after the step (3). 3. The method for producing an inorganic phosphor according to claim 1, wherein a sol-gel method is used as the liquid phase method. 4. The method for producing an inorganic phosphor according to claim 1, wherein a crystallization method is used as the liquid phase method. 5. The step of heating the inorganic phosphor precursor while exposing it to an atmosphere containing oxygen is 600 ° C. or more and 1000 ° C.
It is the following, The manufacturing method of the inorganic fluorescent substance in any one of Claims 1-4 characterized by the following. 6. The inorganic material according to claim 1, wherein the step of heating the inorganic phosphor precursor while exposing it to an atmosphere containing oxygen is for 30 minutes or more and 90 minutes or less. Method for manufacturing phosphor. 7. The oxygen-containing atmosphere has an oxygen concentration of 1%.
It is 50% or less and 50% or more, The manufacturing method of the inorganic fluorescent substance in any one of Claims 1-6 characterized by the above-mentioned. 8. The inorganic material according to claim 1, wherein the step of heating the inorganic phosphor precursor while exposing it to a weakly reducing atmosphere is 1000 ° C. or more and 1800 ° C. or less. Method for manufacturing phosphor. 9. The weakly reducing atmosphere has an oxygen concentration of 0 or more and 1 or more.
It is below 00 ppm, The manufacturing method of the inorganic fluorescent substance in any one of Claims 1-8 characterized by the above-mentioned. 10. The weakly reducing atmosphere has a hydrogen concentration of 0.1.
% Or more and 10% or less, It is characterized by the above-mentioned.
The method for producing the inorganic phosphor according to any one of 1. 11. In the step of heating while exposing to an atmosphere containing oxygen and the step of heating while exposing to a weakly reducing atmosphere, the atmosphere gas is allowed to flow at a flow rate of 0.1 liter / min or more and 10 liter / min or less. The method for producing an inorganic phosphor according to any one of claims 1 to 10, which is characterized in that. 12. The method according to claim 1, wherein after the step of heating while exposing to an atmosphere containing oxygen, a vacuum state of 1.33 × 10 ³ Pa or less is applied, and then the atmosphere is replaced with a weak reducing atmosphere. The method for producing the inorganic phosphor according to any one of items. 13. The method for producing an inorganic phosphor according to claim 1, wherein the inorganic phosphor contains Ba, Mg, Al and an activator. 14. The method for producing an inorganic phosphor according to claim 1, wherein the inorganic phosphor contains Ba, Si and an activator. 15. The method for producing an inorganic phosphor according to claim 1, wherein the inorganic phosphor contains Y, V and an activator. 16. The method for producing an inorganic phosphor according to claim 1, wherein the inorganic phosphor contains Sr, P, Cl and an activator. 17. The inorganic phosphor is Ba, Ca, Mg, P,
Cl and an activator are contained, It is characterized by the above-mentioned.
13. The method for producing an inorganic phosphor according to any one of 12. 18. The method for producing an inorganic phosphor according to claim 1, wherein the inorganic phosphor contains Sr, Mg, P and an activator. 19. An inorganic phosphor obtained by the method for producing an inorganic phosphor according to any one of claims 1 to 18.