JP2003342562A - Method for producing inorganic fluorescent material and inorganic fluorescent material produced thereby - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an inorganic fluorescent material having excellent controllability of luminescent property, particle size and particle size distribution and provide an inorganic fluorescent material produced by the method. <P>SOLUTION: The method for the production of an inorganic fluorescent material contains a baking step to raise the temperature in a manner that the average heating rate U<SB>0</SB>from the heat-starting temperature t<SB>0</SB>to an arbitrary temperature t<SB>1</SB>is set to be higher than the average heating rate U<SB>t</SB>from the arbitrary temperature t<SB>1</SB>to the heat-finishing temperature T<SB>1</SB>. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, various inorganic phosphors have been used in various fields. For example, in a three-wavelength fluorescent lamp which is an example of a lighting device, a phosphor that emits three wavelengths of blue, green and red is used as a phosphor, and a cathode ray tube (CRT) that is an example of a display device. Various phosphors are also used in plasma display panels (PDPs), electroluminescent devices, active light emitting liquid crystal devices, and the like.

By the way, these inorganic phosphors can usually be produced by firing various phosphor raw material mixtures. This firing step is a step in which the activator element diffuses into the host crystal at the same time when the host crystal of the phosphor grows,
This is an important step that affects the emission characteristics of the obtained phosphor. In particular, temperature control in the firing step and cooling control after the firing step are extremely important in order to obtain stable characteristics of the phosphor such as emission characteristics of the phosphor, particle size and particle size distribution.

[0004]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above problems, and its object is to:
It is an object of the present invention to provide a method for producing an inorganic phosphor excellent in controllability of light emission characteristics, particle size and particle size distribution, and an inorganic phosphor obtained by the production method.

[0005]

The object of the present invention can be achieved by adopting the following constitution.

1. As the average heating rate U ₀ from temperature increase start temperature t ₀ to an arbitrary temperature t _1, is faster than the average heating rate U _t from any temperature t ₁ to a temperature T ₁ of the at the end heating A method for producing an inorganic phosphor, comprising a firing step of raising the temperature.

2. The method for producing an inorganic phosphor according to the above item 1, wherein the curve showing the change of the temperature rising rate with respect to temperature has n (n is a natural number of 1 or more) inflection point or refraction point.

3. Or to maintain the average Atsushi Nobori rate U _t from the mean heating rate U ₀ or any temperature t ₁ from temperature increase start temperature t ₀ to an arbitrary temperature t ₁ to a temperature T ₁ of the at the end of heating at a constant rate Or the method for producing an inorganic phosphor according to the item 1 or 2, wherein the temperature is changed continuously or intermittently with respect to temperature.

4. Cooling step in which the average temperature decrease rate D ₀ from the temperature decrease start temperature T ₂ to the arbitrary temperature t ₂ is higher than the average temperature decrease rate D ₁ from the arbitrary temperature t ₂ to the temperature t ₃ at the end of the temperature decrease A method for producing an inorganic phosphor, which comprises:

5. 5. The method for producing an inorganic phosphor according to the item 4, wherein the curve showing the change of the temperature falling rate with respect to temperature has n (n is a natural number of 1 or more) inflection point or refraction point.

6. The average cooling rate D ₀ from the cooling start temperature T ₂ to the arbitrary temperature t ₂ or the average cooling rate D ₁ from the arbitrary temperature t ₂ to the temperature t ₃ at the end of the cooling is maintained at a constant rate or The method for producing an inorganic phosphor as described in 4 or 5 above, wherein the method is changed continuously or intermittently.

7. A method for producing an inorganic phosphor, wherein the method for producing an inorganic phosphor according to any one of claims 1 to 3 and the method for producing an inorganic phosphor according to any one of claims 4 to 6 are used in combination.

8. An inorganic phosphor manufactured by the method for manufacturing an inorganic phosphor according to any one of 1 to 7 above.

The present invention will be described in detail below. The method for producing an inorganic phosphor of the present invention includes a step of preparing an inorganic phosphor precursor, a firing step of firing the inorganic phosphor precursor to obtain an inorganic phosphor, and a cooling step of performing cooling after firing. . A step of surface treatment of particles may be included if necessary.

In the present invention, in the firing step, the average heating rate U ₀ from the heating start temperature t ₀ to an arbitrary temperature t _{1 is} increased.
Is higher than the average temperature increase rate U ₁ from the arbitrary temperature t ₁ to the temperature T ₁ at the end of temperature increase (where t ₀ <t
₁ <T ₁ ).

In the step of firing the inorganic phosphor precursor, the activator element begins to diffuse into the host crystal at the same time as the host crystal of the phosphor grows. At this time, in the present invention, the light emission characteristics, particle size and particle size distribution of the obtained phosphor crystal are controlled by adjusting the heating rate as described above.

The temperature rising rate is limited as long as the above conditions are satisfied.
And may be changed in any manner with respect to temperature. example
For example, the temperature rise start temperature t₀To any temperature t₁Until the average rise
Temperature rate U ₀After holding and growing the host crystal,
Temperature t₁To the temperature T at the end of heating₁Up to average heating rate
U_t(However, U_t<U₀) To suppress the growth of the host crystal.
You may control. Even if the heating rate is changed with temperature,
Well, the change with temperature is continuous, but intermittent.
It may be. It also combines continuous and intermittent changes
You may let me. When changing the heating rate with temperature
Is an nth-order function (n = 1, 2 or 3), an exponential function,
Alternatively, it may be changed in a differential function. In addition, to temperature
The change in the heating rate against the hysteresis curve, cos
It may be a temperature rising pattern showing a function or the like.

FIG. 1 shows some aspects of the heating pattern of the firing step, but the present invention is not particularly limited to this.

Further, in the present invention, the curve showing the change of the temperature rising rate with respect to temperature may or may not have a bending point or an inflection point. Is also not particularly limited. Here, the refraction point means an intersection of two straight lines having different slopes in a curve formed by connecting a plurality of straight lines having different slopes. On the other hand, the inflection point refers to the inflection point that the approximated curve has when a curve made up of non-straight lines is approximated to a curve in which a plurality of straight lines having different slopes are combined.

In the present invention, in the cooling step, the average cooling rate D ₀ from the cooling start temperature T ₂ to an arbitrary temperature t _{2 is} increased.
Is lower than the average temperature decrease rate D ₁ from the arbitrary temperature t ₂ to the temperature t ₃ at the end of the temperature decrease (where t ₃ <t
₂ <T ₂ ).

In the cooling step after firing the inorganic phosphor precursor,
At the same time as the growth of the host crystal of the phosphor is stopped, the particle size and particle shape are stabilized. At this time, in the present invention, the emission rate, particle size and particle size distribution of the obtained phosphor crystal are controlled by adjusting the temperature lowering rate as described above.

The cooling rate is limited to the above-mentioned conditions.
And may be changed in any manner with respect to temperature. example
For example, the temperature start temperature T₂To any temperature t₂Until the average drop
Temperature rate D ₀Hold any temperature t₂The temperature at the end of cooling
Degree t₃Up to average temperature decrease rate D_t(However, D_t<D₀)
The particle size and the particle shape may be stabilized.
The rate of temperature decrease may be changed with respect to temperature and
The changes that occur may be continuous or intermittent.
Further, continuous change and intermittent change may be combined. Descending
When changing the temperature rate with respect to the temperature,
(N = 1, 2 or 3), exponential or differential function
May be changed. Other rate of temperature drop
Changes show hysteresis curve, cos function, etc.
It may be a temperature drop pattern.

FIG. 2 shows some aspects of the temperature lowering pattern of the temperature lowering step, but the present invention is not limited to this.

Further, in the present invention, the curve showing the change of the cooling rate with respect to temperature may or may not have a bending point or a refraction point. Is not particularly limited. Here, the refraction point means an intersection of two straight lines having different slopes in a curve formed by connecting a plurality of straight lines having different slopes. On the other hand, the inflection point refers to the inflection point that the approximated curve has when a curve made up of non-straight lines is approximated to a curve in which a plurality of straight lines having different slopes are combined.

For the method for producing the inorganic phosphor of the present invention, various production methods such as a conventionally known solid phase method and liquid phase method can be applied. Among them, the liquid phase method is applied. Is preferred. In particular, the step of preparing the inorganic phosphor precursor does not undergo a mechanical crushing step at the time of preparation from the viewpoint of emission intensity, that is, those synthesized by the build-up method are preferable, and those manufactured by the liquid phase method are preferable. preferable.

(Liquid phase method) The liquid phase method includes coprecipitation method, crystallization method,
It represents a general reaction method in a liquid phase such as a sol-gel method, and can be appropriately selected in the present invention.

The liquid phase method according to the present invention is preferably, but not limited to, a sol-gel method or a crystallization method. Among the crystallization methods, the reaction crystallization method is preferable.

In the sol-gel method, an element (metal) generally used in a matrix, an activator or a co-activator, such as Si, is used.
Double alkoxides (for example, Al (OC ₄ H ₉ ) ₃ of metal alkoxides such as (OCH ₃ ) ₄ and Eu ³⁺ (CH ₃ COCHCOCH ₃ ) ₃ or metal complexes or organic solvent solutions thereof added with a metal simple substance. Mg [Al (OC ₄ H ₉ ) ₄ ] made by adding metallic magnesium to a 2-butanol solution
₂ etc.), a metal halide, a metal salt of an organic acid, or a metal simple substance is mixed in a necessary amount and thermally or chemically polycondensed.

The reaction crystallization method includes cooling, evaporation, pH adjustment,
When the physical or chemical environment changes due to concentration, or when the state of the mixed system changes due to a chemical reaction, it is the precipitation of the solid phase from the liquid phase, which is generally called the crystallization phenomenon. However, it means a manufacturing method in which physical and chemical operations that induce the occurrence of such a crystallization phenomenon are performed.

As the solvent when applying the sol-gel method,
Any material may be used as long as the reaction raw material is dissolved, but ethanol is preferable from the viewpoint of environment. As the reaction initiator or catalyst, either an acid or a base can be used, but a base is preferred from the viewpoint of the hydrolysis rate. As the type of base, common ones such as sodium hydroxide and ammonia can be used if the reaction starts, but ammonia is preferred from the viewpoint of easy removal. As a method of mixing the reaction initiator or the catalyst, it may be added to the mother liquor in advance, may be added at the same time as the raw materials, or may be added to the raw materials in advance. The method of being added to the mother liquor is more preferable. When using a plurality of reaction raw materials, the order of addition of the raw materials may be the same or different, and a suitable order can be appropriately assembled depending on the activity, and a double alkoxide may be formed in some cases.

Any solvent may be used when the reaction crystallization method is applied as long as the reaction raw materials are dissolved, but water is preferable from the viewpoint of easy control of supersaturation. When using a plurality of reaction raw materials, the order of adding the reaction raw materials may be the same or different, and an appropriate order can be appropriately assembled depending on the activity.

When the precursor is synthesized by the liquid phase method, the temperature, the addition rate, the stirring rate, the pH, etc. may be controlled during the reaction in any method, and ultrasonic waves may be irradiated during the reaction. .
Surfactants, polymers to control particle size or prevent agglomeration
Gelatin or the like may be added. It is also one of the preferred embodiments that the liquid is concentrated and / or aged if necessary after the completion of the addition of the raw materials.

After synthesizing the precursor by the liquid phase method, if necessary, it is recovered by a method such as filtration, evaporation to dryness, centrifugation, and then preferably washed, and further subjected to various steps such as drying and firing. Well, you may classify.

The drying temperature is not particularly limited, but it is preferably a temperature around the temperature at which the solvent used is vaporized or higher, and specifically 50 to 300 ° C. is preferable.

The method for producing an inorganic phosphor of the present invention is described above.
After the step of preparing the inorganic phosphor precursor, there is a baking step of baking the inorganic phosphor precursor to obtain the inorganic phosphor, and a cooling step of cooling after the baking.

The temperature rising rate in the firing step is characterized by being performed under the above conditions, but the firing temperature in the firing step is not particularly limited, and generally 600 to 1800 ° C. can be preferably used. The firing time at the time of firing varies depending on the filling amount of the inorganic phosphor precursor, the firing temperature, the temperature at which it is taken out of the furnace, etc., but is generally 0.5 to 6 hours, preferably 1 to
3 hours is more preferred. The firing may be performed under any conditions such as a reducing atmosphere, an oxidizing atmosphere, the presence of sulfides or the presence of an inert gas, and can be appropriately selected. Various firing methods known at present can be used, but it is preferable to use a rotary firing apparatus. Furthermore,
If necessary, reduction treatment or oxidation treatment may be performed after firing.

In the method for producing an inorganic phosphor of the present invention, after passing through the firing step, a cooling step is performed. The cooling rate in the cooling step is characterized by being performed under the above conditions, but the cooling method in the cooling step is not particularly limited and can be appropriately selected from known cooling methods, using a cooler or the like. A method of controlling the temperature to a desired temperature and cooling is preferable.

If necessary, various general steps such as a washing step, a drying step, and a sieving step can be added to the cooled inorganic phosphor.

The composition of the inorganic phosphor produced by the method for producing an inorganic phosphor of the present invention is, for example, JP-A-50-6.
No. 410, No. 61-65226, No. 64-2
2987, 64-60671, and JP-A-1
No. 168911 and the like, and is not particularly limited, but is a crystal matrix such as Y ₂ O ₂ S, Zn ₂ SiO ₄ , and Ca.
₅ (PO ₄ ) ₃ Cl and other metal oxides and Zn
S, SrS, CaS, and other sulfides have Ce, P
r, Nd, Pm, Sm, Eu, Gd, Tb, Dy, H
ions of rare earth metals such as o, Er, Tm, Yb and Ag,
A combination of ions of metals such as Al, Mn and Sb as an activator or co-activator is preferable.

Preferred examples of the crystal matrix are, for example,
ZnS, Y₂O₂S, Y₃Al_FiveO₁₂, Y₂SiO_Five, Zn₂
SiO_Four, Y₂O₃, BaMgAl_TenO₁₇, BaAl₁₂O
₁₉, (Ba, Sr, Mg) O · aAl₂O₃, (Y, G
d) BO₃, YO₃, (Zn, Cd) S, SrGa₂S_Four,
SrS, GaS, SnO₂, Ca_Ten(PO_Four)₆(F, C
l)₂, (Ba, Sr) (Mg, Mn) Al_TenO₁₇,
(Sr, Ca, Ba, Mg)_{1 0}(PO_Four)₆Cl₂, (L
a, Ce) PO_Four, CeMgAl₁₁O₁₉, GdMgB_FiveO
_Ten, Sr₂P₂O₇, Sr_FourAl₁₄O_{twenty five}Etc.

The crystal matrix and the activator or co-activator described above may be partially replaced with a homologous element, and there is no problem.
There is no particular limitation on the elemental composition.

Examples of compounds of the inorganic phosphor according to the present invention are shown below, but the present invention is not limited to these compounds.

[Blue emitting inorganic phosphor] (BL-1) Sr ₂ P ₂ O ₇ : Sn ⁴⁺ (BL-2) Sr ₄ Al ₁₄ O ₂₅ : Eu ²⁺ (BL-3) BaMgAl ₁₀ O ₁₇ : Eu ²⁺ (BL-4) SrGa ₂ S ₄ : Ce ³⁺ (BL-5) CaGa ₂ S ₄ : Ce ³⁺ (BL-6) (Ba, Sr) (Mg, Mn) Al ₁₀ O
₁₇ : Eu ²⁺ (BL-7) (Sr, Ca, Ba, Mg) ₁₀ (P
O ₄ ) ₆ Cl ₂ : Eu ²⁺ (BL-8) ZnS: Ag (BL-9) CaWO ₄ (BL-10) Y ₂ SiO ₅ : Ce ³⁺ (BL-11) ZnS: Ag, Ga, Cl _{(BL-12) Ca 2 B} 5 O 9 Cl: Eu 2+ (BL-13) BaMgAl 14 O 23: Eu 2+ (BL-14) BaMgAl 10 O 17: Eu 2+, T
b ³⁺ , Sm ²⁺ (BL-15) BaMgAl ₁₄ O ₂₃ : Sm ²⁺ (BL-16) Ba ₂ Mg ₂ Al ₁₂ O ₂₂ : Eu ²⁺ (BL-17) Ba ₂ Mg ₄ Al ₈ O ₁₈ : Eu ²⁺ (BL-18) Ba ₃ Mg ₅ Al ₁₈ O ₃₅ : Eu ²⁺ (BL-19) (Ba, Sr, Ca) (Mg, Zn,
Mn) Al ₁₀ O ₁₇ : Eu ²⁺ [green light emitting inorganic phosphor] (GL-1) (Ba, Mg) Al ₁₆ O ₂₇ : Eu ²⁺ , M
n ²⁺ (GL-2) Sr ₄ Al ₁₄ O ₂₅ : Eu ²⁺ (GL-3) (Sr, Ba) Al ₂ Si ₂ O ₈ : Eu ²⁺ (GL-4) (Ba, Mg) ₂ SiO ^{_{4: Eu 2+ (GL-5}} ) Y 2 SiO 5: Ce 3+, Tb 3+ (GL-6) Sr 2 P 2 O 7 -Sr 2 B 2 O 5: Eu 2+ (GL-7) ( Ba, Ca, Mg) ₅ (PO ₄ ) ₃ C
l: Eu ²⁺ (GL-8) Sr ₂ Si ₃ O ₈ -2SrCl ₂ : Eu ²⁺ (GL-9) Zr ₂ SiO ₄ , MgAl ₁₁ O ₁₉ : C
e ³⁺ , Tb ³⁺ (GL-10) Ba ₂ SiO ₄ : Eu ²⁺ (GL-11) ZnS: Cu, Al (GL-12) (Zn, Cd) S: Cu, Al (GL-13) ZnS: Cu, Au, Al ( GL-14) Zn 2 SiO 4: Mn 2+ (GL-15) ZnS: Ag, Cu (GL-16) (Zn, Cd) S: Cu (GL-17) ZnS: Cu (GL-18) Gd ₂ O ₂ S: Tb ³⁺ (GL-19) La ₂ O ₂ S: Tb ³⁺ (GL-20) Y ₂ SiO ₅ : Ce ³⁺ , Tb ³⁺ (GL-21 ) Zn ₂ GeO ₄ : Mn ²⁺ (GL-22) CeMgAl ₁₁ O ₁₉ : Tb ³⁺ (GL-23) SrGa ₂ S ₄ : Eu ²⁺ (GL-24) ZnS: Cu, Co (GL-25). _{MgO · nB 2 O 3: Ce} 3+, Tb 3+ (GL-26) LaOBr: Tb 3+, Tm 3+ (GL _{27) La 2 O 2 S:} Tb 3+ (GL-28) SrGa 2 S 4: Eu 2+, Tb 3+, Sm
²⁺ [red emitting inorganic _{phosphor] (RL-1) Y 2} O 2 S: Eu 3+ (RL-2) (Ba, Mg) 2 SiO 4: Eu 3+ (RL-3) Ca 2 Y 8 ( _{SiO 4) 6 O 2: Eu} 3+ (RL-4) LiY 9 (SiO 4) 6 O 2: Eu 3+ (RL-5) (Ba, Mg) Al 16 O 27: Eu 3+ (RL-6 ) (Ba, Ca, Mg) ₅ (PO ₄ ) ₃ C
^{l: Eu 3+ (RL-7} ) YVO 4: Eu 3+ (RL-8) YVO 4: Eu 3+, Bi 3+ (RL-9) CaS: Eu 3+ (RL-10) Y 2 O 3 : Eu ³⁺ (RL-11) 3.5MgO, 0.5MgF ₂ Ge
^{_{O 2: Mn 4+ (RL-}} 12) YAlO 3: Eu 3+ (RL-13) YBO 3: Eu 3+ (RL over 14) (Y, Gd) BO 3: Eu 3+ inorganic phosphor of the present invention The average particle size of the inorganic phosphor produced by the production method is preferably 0.1 to 1.0 μm,
0.2 to 0.8 μm is more preferable. The above-mentioned average particle size is a sphere-converted particle size, and 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 according to the present invention is the transmission electron microscope “TEM” or the scanning electron microscope “SE”.
It can be measured using "M". The particle size is preferably 0.1
Inorganic phosphors having particles of ˜1.0 μm occupy 50% or more of all particles by mass, more preferably having a particle size of 0.1 to 1.0.
It is an inorganic phosphor in which particles of μm occupy 70% or more of all particles by mass. Furthermore, an inorganic phosphor having a variation coefficient of particle size distribution of particles having an average particle diameter of 0.1 to 1.0 μm of 50% or less is preferable, and an inorganic phosphor having a variation coefficient of 30% or less is more preferable. Here, 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 (%) = (standard deviation of particle size / average particle size) × 100

[0045]

EXAMPLES The present invention will be specifically described below with reference to examples, but the embodiments of the present invention are not limited thereto.

Example 1 Production of "inorganic phosphor (GL-14-1)" (compositional formula: Z
n ₂ SiO ₄ : Mn ²⁺ ) An inorganic phosphor precursor was manufactured by the following reaction crystallization method.

45 g of gelatin and 0.1 m of Na ₂ SiO ₃
was dissolved in 200 ml of water, and the solution was designated as "A solution".

0.19 mol of ZnCl ₂ was added to 200 m of water.
It was dissolved in 1 at 60 ° C., and the solution was designated as “B solution”.

0.01 mol of MnCl ₂ .4H ₂ O was dissolved in 50 ml of water, and the solution was designated as "C liquid".

While maintaining the "liquid A" at 40 ° C., under stirring,
"B liquid" and "C liquid" are added at a constant rate at the same time, and after addition,
It was aged at 40 ° C. for 2 hours. Then, the deposited inorganic phosphor precursor is filtered and separated, and dried at 100 ° C. for 10 hours,
"Inorganic phosphor precursor (GP-14-1)" was obtained.

In the firing step, an inorganic titanate precursor (GP-14-GP-14-
1) ”, and the temperature rise rate in the atmosphere is 700 at a rate of 8 ° C./min.
After heating to ℃, change the heating rate to 4 ℃ / min
It was heated up to 000 ° C. and subjected to a firing treatment at the same temperature for 3 hours. After firing, the cooling rate is 200 ° C at 4 ° C / min in the cooling process.
After cooling to room temperature, the fired product is taken out and the composition formula: Zn _1.9
SiO ₄ : Mn ²⁺ _0.1 "inorganic phosphor (GL-14-
1) ”was obtained. The obtained "inorganic phosphor (GL-14-
1) ”means a maximum excitation wavelength of 235 nm and a maximum emission wavelength of 52
It was 4 nm.

Next, the obtained "inorganic phosphor (GL-14
−1) ”was measured, and the variation coefficient of the average particle size and the particle size distribution was calculated.

The emission intensity was measured by irradiating ultraviolet rays of 235 nm as an excitation source and measuring the emission intensity of 524 nm.

The average particle size and the coefficient of variation of the particle size distribution were calculated from the results of measurement for 100 arbitrary phosphor particles using a scanning electron microscope "SEM".

The results obtained are shown in Table 1. Example 2 Production of “inorganic phosphor (GL-14-2)” (compositional formula: Z
n ₂ SiO ₄ : Mn ²⁺ ) In the production of “inorganic phosphor (GL-14-1)” described in Example 1, in the firing step of “inorganic phosphor precursor (GP-14-1)”, Heating rate 4
It was heated to 1000 ° C. at a rate of ° C./minute and calcined at the same temperature for 3 hours. After firing, in the cooling step, the cooling rate was 8 ° C /
In minutes, and then cooled to 200 ° C. by changing the cooling rate to 4 ° C./minute, and in the same manner as in Example 1, “inorganic phosphor (GL-14-2)” was obtained. It was The obtained "inorganic phosphor (GL-14-2)" had a maximum excitation wavelength of 235 nm and a maximum emission wavelength of 524 nm.

In the same manner as in Example 1, the emission intensity of the obtained "inorganic phosphor (GL-14-2)" was measured, and the average particle size and the coefficient of variation of the particle size distribution were calculated. The results obtained are shown in Table 1.

Example 3 Production of "inorganic phosphor (GL-14-3)" (compositional formula: Z
n ₂ SiO ₄ : Mn ²⁺ ) In the production of “inorganic phosphor (GL-14-1)” described in Example 1, in the firing step of “inorganic phosphor precursor (GP-14-1)”, Temperature rising rate is 8
Heat up to 700 ℃ at ℃ / minute, then increase the temperature by 4 ℃
/ Min, heated to 1000 ° C, subjected to calcination treatment at the same temperature for 3 hours, and after calcination, cooling rate is 8 ° C in the cooling step.
At a cooling rate of 4 ° C / min.
"Inorganic phosphor (GL-14-3)" was obtained in the same manner as in Example 1 except that the temperature was changed to minutes and the temperature was cooled to 200 ° C.
The obtained "inorganic phosphor (GL-14-3)" had a maximum excitation wavelength of 235 nm and a maximum emission wavelength of 524 nm.

In the same manner as in Example 1, the emission intensity of the obtained "inorganic phosphor (GL-14-3)" was measured, and the average particle size and the coefficient of variation of the particle size distribution were calculated. The results obtained are shown in Table 1.

Example 4 Production of "inorganic phosphor (GL-14-4)" (compositional formula: Z
n ₂ SiO ₄ : Mn ²⁺ ) In the production of “inorganic phosphor (GL-14-1)” described in Example 1, in the firing step of “inorganic phosphor precursor (GP-14-1)”, Heating rate is 1
Heat at 0 ° C / min to 800 ° C, then increase the heating rate to 4
The temperature is changed to ℃ / min and heated up to 1000 ℃, calcination is performed for 3 hours at the same temperature, and after calcination, the cooling rate is 1 in the cooling step.
Cool to 400 ° C at 0 ° C / min, then cool at 4
Example 1 except that the temperature was changed to ° C / min and the temperature was cooled to 200 ° C.
In the same manner as in, "Inorganic phosphor (GL-14-4)" was obtained. The obtained "inorganic phosphor (GL-14-4)" had a maximum excitation wavelength of 235 nm and a maximum emission wavelength of 524 nm.

In the same manner as in Example 1, the emission intensity of the obtained "inorganic phosphor (GL-14-4)" was measured, and the average particle size and the coefficient of variation of the particle size distribution were calculated. The results obtained are shown in Table 1.

Example 5 "Production of Inorganic Phosphor (GL-14-5)" (Compositional Formula: Z
n ₂ SiO ₄ : Mn ²⁺ ) In the production of “inorganic phosphor (GL-14-1)” described in Example 1, in the firing step of “inorganic phosphor precursor (GP-14-1)”, Heating rate 4
The same procedure as in Example 1 was performed except that the temperature was heated to 1000 ° C at a rate of 3 ° C / minute, the baking was performed at the same temperature for 3 hours, and after the baking, the cooling rate was 4 ° C / minute to 200 ° C in the cooling step. Thus, "inorganic phosphor (GL-14-5)" was obtained. The obtained "inorganic phosphor (GL-14-5)" had a maximum excitation wavelength of 235 nm and a maximum emission wavelength of 524 nm.

In the same manner as in Example 1, the emission intensity of the obtained "inorganic phosphor (GL-14-5)" was measured, and the average particle size and the coefficient of variation of the particle size distribution were calculated. The results obtained are shown in Table 1.

Example 6 Production of "inorganic phosphor (GL-14-6)" (compositional formula: Z
n ₂ SiO ₄ : Mn ²⁺ ) In the production of “inorganic phosphor (GL-14-1)” described in Example 1, in the firing step of “inorganic phosphor precursor (GP-14-1)”, Temperature rising rate is 8
The same procedure as in Example 1 was repeated except that heating was performed at 1000 ° C./minute to 1000 ° C., baking treatment was performed at the same temperature for 3 hours, and after baking, the cooling rate was 8 ° C./minute to 200 ° C. in the cooling step. Thus, "inorganic phosphor (GL-14-6)" was obtained. The obtained "inorganic phosphor (GL-14-6)" had a maximum excitation wavelength of 235 nm and a maximum emission wavelength of 524 nm.

In the same manner as in Example 1, the emission intensity of the obtained "inorganic phosphor (GL-14-6)" was measured, and the average particle size and the coefficient of variation of particle size distribution were calculated. The results obtained are shown in Table 1.

[0065]

[Table 1]

As is clear from Table 1, the inorganic phosphor manufactured by using the temperature rising pattern and / or the temperature falling pattern of the present invention has high emission intensity, a small particle size, and a narrow particle size distribution can be controlled. You can see that

[0067]

INDUSTRIAL APPLICABILITY As demonstrated in the examples, the method for producing an inorganic phosphor of the present invention and the inorganic phosphor obtained by the production method are excellent in light emission characteristics, particle size and controllability of particle size distribution. Have.

[Brief description of drawings]

FIG. 1 is a diagram showing some aspects of a heating pattern of a firing step according to the present invention.

FIG. 2 is a diagram showing some aspects of the cooling pattern of the cooling step according to the present invention.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Naohiro Okada             Konica Stock Market, 1 Sakura-cho, Hino City, Tokyo             In-house (72) Inventor Hideki Hoshino             Konica Stock Market, 1 Sakura-cho, Hino City, Tokyo             In-house F-term (reference) 4H001 CA01 CF02

Claims (8)

[Claims] 1. A mean heating rate U ₀ from temperature increase start temperature t ₀ to an arbitrary temperature t ₁ is than the average heating rate U _t from any temperature t ₁ to a temperature T ₁ of the at the end heating A method for producing an inorganic phosphor, comprising a firing step of raising the temperature so as to be faster. 2. The inorganic fluorescence according to claim 1, wherein the curve showing the change of the temperature rising rate with respect to temperature has n (n is a natural number of 1 or more) inflection point or inflection point. Body manufacturing method. Wherein an average heating rate U _t from the mean heating rate U ₀ or any temperature t ₁ from temperature increase start temperature t ₀ to an arbitrary temperature t ₁ to a temperature T ₁ of the at the end of heating constant The method for producing an inorganic phosphor according to claim 1 or 2, wherein the method is maintained at a speed or is continuously or intermittently changed with respect to temperature. 4. The average cooling rate D ₀ from the cooling start temperature T ₂ to an arbitrary temperature t ₂ is faster than the average cooling rate D ₁ from the arbitrary temperature t ₂ to the temperature t ₃ at the end of cooling. A method for producing an inorganic phosphor, which comprises a cooling step of lowering the temperature. 5. The inorganic phosphor according to claim 4, wherein the curve showing the change of the temperature decreasing rate with respect to temperature has n (n is a natural number of 1 or more) inflection point or inflection point. Manufacturing method. 6. The average temperature decrease rate D ₀ from the temperature decrease start temperature T ₂ to an arbitrary temperature t ₂ or the average temperature decrease rate D ₁ from the arbitrary temperature t ₂ to the temperature t ₃ at the end of the temperature decrease is maintained at a constant speed. Alternatively, the method for producing an inorganic phosphor according to claim 4 or 5, wherein the temperature is changed continuously or intermittently with respect to temperature. 7. An inorganic fluorescent material, characterized in that the method for producing an inorganic fluorescent material according to any one of claims 1 to 3 and the method for producing an inorganic fluorescent material according to any one of claims 4 to 6 are used in combination. Body manufacturing method. 8. An inorganic phosphor manufactured by the method for manufacturing an inorganic phosphor according to any one of claims 1 to 7.