WO1998042797A1

WO1998042797A1 - Process for producing aluminate phosphor

Info

Publication number: WO1998042797A1
Application number: PCT/JP1998/001324
Authority: WO
Inventors: Hirofumi Moriyama; Tomofumi Moriyama; Yukie Kobayashi
Original assignee: Kabushiki Kaisha Tokyo Kagaku Kenkyusho
Priority date: 1997-03-26
Filing date: 1998-03-25
Publication date: 1998-10-01

Abstract

A process for producing a three-band or photostimulable aluminate phosphor, which comprises mixing feedstocks including an α-alumina powder having a primary-particle diameter of 0.3 to 30 νm and being substantially from fractures and then baking the mixture without fluxing the feedstock α-alumina particles. The phosphor thus obtained can be easily powdered, has excellent luminescent properties because of a small content of fine particles, attains a high product yield, and retains the particle diameter of the α-alumina powder.

Description

Specification

Method for producing aluminate phosphor

Technical field

The present invention relates to, for example, an aluminate-based phosphor used for a three-wavelength fluorescent lamp that emits blue, blue-green, or green light when excited by ultraviolet light, or a long-time excited by ultraviolet light or visible light. The present invention relates to a method for producing an aluminate-based phosphor, which has an afterglow characteristic used as a phosphorescent material having an afterglow property.

Background art

Since the production of fluorescent lamps in 1938, characteristics such as luminous brightness, luminous efficiency, color rendering, and life have been improved. In recent years, fluorescent lamps that are close to natural light with improved color rendering properties, so-called “three-wavelength fluorescent lamps,” have been developed by concentrating fluorescence strongly around the wavelengths of 450 nm (blue), 540 nm (green), and 610 nm (red). Widely used.

In this three-wavelength fluorescent lamp, for example, a blue phosphor is a barium-magnesium aluminate phosphor, a green phosphor is a cerium-magnesium-aluminate phosphor, and a red phosphor is an oxidized phosphor. It has been used in situ phosphors.

For example, for the production of aluminate phosphors of blue or green phosphors, magnesium (Mg), barium (Ba), and strontium (Sr) constituting an aluminate are added to an alumina powder. , Calcium (Ca), zinc (Zn) or cerium (Ce) compound powder, and a small amount of europium (Eu), manganese as an activator for producing luminescence. A raw material to which at least one (Mn) or terbium (Tb) is added and mixed is used. These mixed raw materials are fired at a high temperature exceeding 1,000 ° C and then pulverized, and then subjected to classification, washing, and other treatments, and used as a phosphor for lamps.

On the other hand, self-luminous luminous paints, in which a radioactive substance is added to a phosphor, have been used for nighttime display and luminous clocks. Recently, the application of phosphorescent phosphors having long-term persistence without using radioactive substances has been widely studied. As a phosphorescent phosphor, for example, europium-activated strontium alumina has been mainly studied (Japanese Patent No. 2543838). Disclosure of the invention

It is well known that the characteristics of phosphors are affected by the primary particle diameter of the phosphor particles, and that the luminous efficiency is higher when the phosphor particles are larger. Therefore, phosphors with a primary particle diameter of 4 to 10 ^ m are generally used as phosphors for three-wavelength fluorescent lamps. In addition, phosphorescent phosphors are usually used! Phosphors with a primary particle size of ~ 50 / m are used. Further, it is well known that the emission characteristics of phosphors are greatly affected by trace impurities. Therefore, high-purity alumina powder, such as high-purity high-purity α-alumina or high-purity α-alumina, is used as the main raw material for the aluminate serving as the base material of the aluminate phosphor. These high-purity alumina powders have a fine primary particle diameter, usually less than 1 / xm, and have strong agglomeration. Therefore, the phosphor after firing forms hard aggregated particles.

On the other hand, the reduction can be achieved by pulverizing these hard aggregated particles, but the particle size distribution after the pulverization becomes wider due to the residual aggregated particles and the generation of fine particles accompanying the powder frame. Therefore, phosphors synthesized using these high-purity alumina powders are powders having a wide particle size distribution from submicron to about 100 / xm.

In other words, the aluminate-based phosphor uses a fine high-purity alumina raw material having a primary particle diameter of less than 1 / zm as the raw material alumina, and grows from a submicron to about 200 m by high-temperature firing. Therefore, the phosphor particles after firing have a wide particle size distribution and are strongly agglomerated and need to be pulverized. In addition, it is essential to remove fine particles and coarse particles by classification. As a result, there have been major problems such as degradation of light emission characteristics due to destruction of primary particles due to pulverization and unevenness of crystallinity, and a low yield as phosphor particles.

Therefore, to date, no phosphorates for tri-wavelength fluorescent lamps and phosphorescent phosphors have been obtained, which are easy to grind, have few fine particles, have excellent emission characteristics, and have a high product yield. .

Under these circumstances, the present inventors have conducted intensive studies and found that as a blue phosphor, a blue-green phosphor, or a green phosphor, an aluminate phosphor and a phosphorescent material suitable for a three-wavelength fluorescent lamp and the like. To find a method for producing aluminate phosphor suitable for Has come to fruition.

The present invention provides an aluminate phosphor which is excellent in light emission characteristics due to easy pulverization and small number of fine particles, has high product yield, and obtains an aluminate-based phosphor while maintaining the particle diameter of α-alumina powder. It is an object of the present invention to obtain a method for producing a phosphor. That is, in the method for producing an aluminate-based phosphor according to the present invention, in the synthesis of the aluminate-based phosphor, a substantially fractured surface having a primary particle diameter of 0.3 / in or more and 30 / m or less is used as a raw material alumina. Α-alumina powder which does not have is used, and when the raw materials are mixed and then fired, the raw α-alumina powder is fired without melting with a flux.

According to one embodiment of the present invention, the aluminate-based phosphor has a general formula

aM.O-bMgO-cA l _a 0 ₃

Is a compound in which europium (Eu) alone or an activator composed of europium (Eu) and manganese (Mn) is added to a composite oxide substrate represented by

M, is at least one metal element selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca);

a is in the range of 0.5 to 4.5, b is in the range of 0 to 4, and c is in the range of 0.5 to 20. Further, according to another aspect of the present invention, an aluminate-based phosphor has a general formula

A compound in which an activator made of terbium (Tb) and / or manganese (Mn) is added to the composite oxide substrate represented by

M ₂ is at least one metal element selected from magnesium (Mg) and zinc (Zn),

d is 0.9 to 1.1, e is 0.9 to 1.1, and f is 5.5.

Further, according to another aspect of the present invention, an aluminate-based phosphor is represented by the following general formula:

hMsOA 1

(M ₃ strontium (S r), calcium (C a;), a compound consisting of at least one metal element selected the group or al consisting Bruno potassium (B a), h is from 0.5 1.1) represented by a composite oxide substrate, europium as an activator (Eu) has been added up to 20% 0.002% or more in terms of mol% relative to metallic elements expressed by M _3, further as a co-activator, \

Lanthanum (La), cerium (Ce;), praseodymium (Pr), neodymium (Nd), samarium (Sm), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), At least one of the group consisting of erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), manganese (Mn), tin (Sn), bismuth (Bi), and scandium (Sc) one or more elements are aluminate phosphor having afterglow characteristics, which are added 0.002% or more and 20% or less in terms of mol% relative to the metal element expressed by M _3.

More specifically, the aluminate-based phosphor is represented by the general formula

(M ₃ strontium (S r), calcium (C a), Bruno helium (B a) group or al compounds comprising at least one or more metal element selected consisting of, h is from 0.5 1.1) complex represented by This is an aluminate phosphor having afterglow characteristics in which at least one metal element selected from lead (Pb), zinc (Zn) and bismuth (Bi) is added to an oxide substrate.

Further, as another specific example of another embodiment, the aluminate-based phosphor is represented by a general formula:

(S r, Eu, Pb, Dy) O-y (A 1, B i) 2 0 ₃

(However, 0.83≤y≤ l. 67)

This is an aluminate-based phosphor having the afterglow characteristic based on the Eu 2 ⁺ -activated strontium-aluminate-based phosphor represented by the following formula.

This is an aluminate-based phosphor having the afterglow characteristic shown by.

For example, as the raw material alumina, as an α-alumina powder having a primary particle diameter of not less than 0.3 / xm and not having a substantially crushed surface of not more than 30 ^ m, an alumina having a purity of 99.9% by weight or more is used. Is the way.

The present invention relates to a method for producing an aluminate-based phosphor which is easy to pulverize and has a small amount of fine particles, has excellent light-emitting characteristics, and has a good product yield. Use α-alumina powder having substantially no crushed surface of am or less. This α-alumina powder includes, for example, Α-alumina sold under the trade name of Devanst alumina can be used (JP-A-6-191833, JP-A-6-191835, JP-A-6-191836).

These primary powders having a primary particle diameter of not less than 0.3 / im and not more than 302 m and having substantially no crushed surface have almost no agglomerated particles and a sharp particle size distribution. Surprisingly, the α-alumina particles are composed of magnesium, which constitutes the aluminate. (Mg), Norium (Ba), Strontium (Sr), Calcium (Ca), Zinc (Zn), Reacted with compounds such as lead (Pb), bismuth (Bi), or cerium (Ce) to find aluminate-based phosphor particles with less fine particles and less aggregation. However, this α-alumina powder has little dispersibility because it has almost no aggregated particles and no fine particles. Magnesium (Mg), barium (Ba), strontium (Sr), calcium (Ca), zinc (Zn), lead (Pb), bismuth (Bi), or cerium (Ce) are homogeneously mixed with a compound powder, so it is thought that the phosphor will be less likely to generate fine particles. .

Further, in the present invention, although the adjacent α-alumina powder is partially melted by being fired without being melted by the flux, the entire α-alumina powder is fired without being melted. . For this reason, aluminate-based phosphors used in three-wavelength fluorescent lamps and the like that maintain the particle diameter of the size derived from the raw material α-alumina powder while maintaining the particle diameter of the alumina powder almost unchanged, An aluminate-based phosphor having light properties can be obtained.

That is, according to the observation by an electron microscope, although the adjacent α-alumina powder is partially melted by firing without using the flux, the particles of the alumina powder are fired almost without being melted, and the raw material α — An aluminate phosphor with a size derived from the particle size of alumina was obtained.

However, a slight difference was observed between the aluminate-based phosphor used in three-wavelength fluorescent lamps and the like and the aluminate-based phosphor having persistence.

For the aluminate-based phosphor used in three-wavelength fluorescent lamps, etc., the measured value of the average particle diameter based on the laser-scattering method is the average particle diameter of the raw material α-alumina powder. About 5 times to about 1.2 times the value of This is due to the adhesion between the obtained phosphors. This phenomenon was particularly large as the average particle diameter of the raw material a-alumina powder was smaller.

In other words, the aluminate-based phosphor obtained by firing without using a flux (flux) such as aluminum fluoride or boric acid has a phosphor with almost no change in the particle diameter of the raw material α-alumina powder. It is fired in a state where the phosphors are adhered to each other with a weak force. For this reason, the crushing or pulverization is easily separated by a force enough to loosen the adhesion between the particle diameters, and the crushing or crushing is easy and the number of fine particles is small. For this reason, an aluminate-based phosphor excellent in light emission characteristics and high in product yield can be easily obtained.

On the other hand, in the case of an aluminate-based phosphor having afterglow, when a general α-alumina powder having a substantially crushed surface is used and fired without adding a flux during firing, All of the raw material α-alumina powder does not melt, but some of the corners of the fracture surface are melted, and the fired crystal becomes a so-called “rounded corner” state. The phosphor is fired while maintaining almost the same. In particular, if the primary particle diameter of the raw material mono-alumina powder is smaller, adjacent particles of the α-alumina powder are fused with each other to form droplet-shaped particles having a primary particle diameter of about several / im. It is fired in a state where particles of about several meters are adhered with weak force. The obtained aluminate-based phosphor having afterglow characteristics is fired in a state in which the fused bodies are bonded to each other with a weak force, so that it is easily applied with a force enough to loosen the bonding between the fused bodies. It comes apart. Therefore, an aluminate-based phosphor having excellent afterglow characteristics and a high product yield and having a long afterglow characteristic can be easily obtained because of easy release and few fine particles.

As described above, by selecting a material having the desired average particle size and particle size distribution as the raw material alumina, it was obtained by firing without using a flux (flux) such as aluminum fluoride or boric acid. The aluminate-based phosphor is fired as a phosphor having almost no difference in particle diameter from the raw material α-alumina powder, and is fired in a state where the phosphors are adhered with a small force. For this reason, the crushing or pulverization is easily separated with a force enough to loosen the adhesion between the particle diameters, so that the crushing or pulverization is easy and the fine particles are reduced. Few. As a result, an aluminate-based phosphor excellent in light emission characteristics and high in product yield can be easily obtained. In addition, aluminate-based materials that have no afterglow characteristics, such as a decrease in afterglow characteristics due to destruction of primary particles due to pulverization and non-uniform crystallinity, and a low yield as phosphor particles. A phosphor is obtained.

By the way, if it exceeds 30 mm, magnesium (Mg), barium (Ba), strontium (Sr), calcium (Ca), zinc (Zn), lead (Pb), bismuth Reaction with compound powder such as (Bi) or cerium (Ce) becomes difficult. Further, in order to enhance the light emission such as luminance, it is preferable that the alumina purity of α-alumina is 99.9% by weight or more.

Magnesium (Mg), barium (Ba), strontium (Sr), calcium (Ca), zinc (Zn), lead (Pb), bismuth (Bi), or cerium that constitutes the aluminate As the compound powder of (Ce), oxides, hydroxides, carbonates, nitrates, halides, and the like that can be decomposed at high temperatures to form oxides can be used.

Aluminate-based phosphor has the general formula aM! O · bMgO · c A 1 2 〇 ₃ europium double engagement oxide substrate represented by (E u) alone or europium (E u) and manganese (M n) In the case of a compound to which an activator consisting of is added, the components are mixed so that a is in the range of 0.5 to 4.5, b is in the range of 0 to 4, and c is in the range of 0.5 to 20.

For example, aluminate-based phosphor is formula a (B a, S r) 0 - bMgO - cA l 2 europium (E u) to the composite oxide substrate represented by Rei_3 alone or europium (E u) In the case of a compound to which an activator made of manganese (Mn) is added, it is preferable that a is in the range of 0.9 to 1.7, b is in the range of 1.5 to 2.1, and c is in the range of 8.

Further, for example, aluminate-based phosphor is formula a (B a, C a) 0 'c A l 2 0 europium (E u) to the composite oxide substrate represented by ₃ alone, or a europium (E u) In the case of a compound to which an activator made of manganese (Mn) is added, a is preferably in the range of 1.0 to 1.5, and c is preferably in the range of 6.

Further, for example, the case of the compounds of europium in the compound oxide substrate aluminate phosphor represented by the general formula a S r O · cA l ₂ 〇 ₃ (E u) is added as an activator, a 3.9 To 4.1 and c are preferably in the range of 7.

On the other hand, shows aluminate phosphor at d C e OLS · eM ₂ 〇 · f A l ₂ 〇 ₃ by formula g

In the case of a compound in which an activator made of terbium (Tb) and / or manganese (Mn) is added to the composite oxide substrate to be used, d is in the range of 0.9 to 1.1, e is in the range of 0.9 to 1.1, and f is in the range of 5.5 Is preferred.

Raw materials such as europium (Eu), manganese (Mn), and terbium (Tb) that act as activators for emitting light include oxides, hydroxides, carbonates, nitrates, and halides at high temperatures. Those which can be decomposed into oxides can be used. .. The amount, for example, aluminate-based phosphor is formula a (B a, S r) 0 · bMgO · c A 1 〇 ₃ europium complex oxide substrate represented by (E u) alone or In the case of an aluminate-based phosphor to which an activator consisting of europium (Eu) and manganese (Mn) is added, the amount of europium (Eu) added is 0.01a to 0.15a, and the amount of manganese (Mn) added is It is preferably in the range of 0.15 b or less.

For example, aluminate-based phosphor is formula a (B a, C a) 〇 · c A 1 〇 ₃ europium complex oxide substrate represented by (E u) alone or with manganese europium (Eu) ( In the case of an aluminate-based phosphor to which an activator consisting of Mn) is added, the amount of europium (Eu) added is 0.01a to 0.15a, and the amount of manganese (Mn) added is 0.20a or less. Is preferably within the range.

For example, aluminate-based phosphor of the general formula a S r O · c A 1 2 0 europium (E u) to the composite oxide substrate represented by ₃ is added, aluminate-based phosphor as an activator In this case, it is preferable that the amount of europium (Eu) be in the range of 0.02 a to 0.06 a.

For example, aluminate-based phosphor is formula dC eOu · eM ₂ 0 - activator consisting of terbium (Tb) and / or manganese (Mn) in the composite oxide substrate to be shown at f A l ₂ 〇 ₃ In the case of the added aluminate-based phosphor, it is preferable that the addition amount of terbium (Tb) is in the range of 0.3d to 0.5d and the addition amount of manganese (Mn) is in the range of 0.15e or less.

After mixing these materials using a ball mill, V-type mixer, etc., they are fired at 1,100 to 1,800 ° C for several hours. Further, the product obtained by the above method is pulverized using a ball mill, a jet mill, or the like, and then washed, but classified if necessary.

Α-alumina with a primary particle size of 0.3 / xm or more and substantially no crushed surface of 30 im or less The aluminate-based phosphor of the present invention obtained by using a powder as a raw material is extremely useful as a three-wavelength fluorescent lamp because it is easy to pulverize, has few fine particles, has excellent emission characteristics, and has a high product yield.

Further, as the aluminate-based phosphor having specific afterglow characteristics produced in the present invention, any phosphor containing an aluminate in a mother crystal may be used. For example, aluminate-based phosphors having afterglow characteristics of several ten minutes to several hours described in Japanese Patent No. 254 3825 and Japanese Patent Application No. 7-112574 are exemplified.

Aluminate-based phosphor having afterglow characteristics, the formula hM ₃ 〇 · A 1 ₂ 〇 ₃ [M ₃ is selected from the group consisting of strontium (S r), calcium (C a), barium (B a) Compound consisting of at least one or more metal elements, h is from 0.5 to 1.1] on a composite oxide substrate represented by: europium (Eu) as an activator, lanthanum (La), cerium (Ce) , Praseodymium (Pr), Neodymium (Nd), Samarium (Sm), Gadolinium (Gd), Terbium (Tb), Dysprosium (Dy), Holmium (Ho), Erbium (Er), Thulium (Tm), Ytterbium (Yb) ), Lutetium (Lu), Manganese (Mn), Tin (Sn), Bismuth (Bi), Scandium (Sc) at least one element was added as a co-activator for compounds, added pressure amount in terms of mol% relative to the metal element expressed by M ₃ 0 It is preferable that it is not less than .002% and not more than 20%.

For example, europium complex oxide substrate phosphorescent aluminate phosphor represented by the general formula h S r O · A 1 ₂ 〇 (Eu) is as an activator, was further added as dysprosium co activator In the case of a compound, h is preferably in the range of 0.9 to 1.1. Further, an aluminate-based phosphor having afterglow characteristics is a composite oxide represented by the general formula hC a〇 · A 1 ₂ ₃ In the case of a compound in which europium (Eu) is added as an activator and neodymium as a coactivator is added to the substrate, h is preferably in the range of 0.9 to 1.1.

Furthermore, for example, a composite oxide substrate to europium (E u) is an activator of luminous aluminate-based phosphor is shown by the formula h S r O · A 1 ₂ 〇, with further Jisupuroshiu arm co For compounds added as activators, europium (Eu) may be added in the range of 0.01 h to 0.1 lh and dysprosium in the range of 0.02 h to 0.2 h. preferable. For example, as an activator europium (E u) is a composite oxide substrate represented phosphorescent aluminate phosphor is by the formula h C aO · A 1 ₂ 〇 _3, further added as activator co neodymium In the case of the compound thus prepared, it is preferable that the addition amount of europium (Eu) is in the range of 0.01 h to 0.1 h, and the addition amount of neodymium is in the range of 0.02 h to 0.2 h. Addition of an activator in a smaller amount or a larger amount than these preferable ranges is not preferable because it lowers the luminance. ... Also, lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), gadolinium (Gd), terbium (Tb), dysprosium ( Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), manganese (Mn), tin (Sn), bismuth (Bi), scandium ( S one at least one metal element of the group consisting of c) general formula 1Iotamyu ₃ 〇 · Α 1 ₂ Ο, - a composite oxide substrate can be 0.1 h added pressure from 0.001 h in shown.

After mixing these materials using a ball mill, V-type mixer, etc., they are fired at 1,100 to 1,800 ° C for several hours. Further, the product obtained by the above method is crushed using a ball mill, a jet mill or the like, and then washed, but classified if necessary.

The aluminate-based phosphor for a phosphorescent material according to the present invention obtained by using an α-alumina powder having a primary particle diameter of 0.3 im or more and 30 m or less and having substantially no crushed surface as a raw material is easily crushed. It has excellent afterglow properties due to its small number of fine particles and is highly useful as a phosphorescent material because of its high product yield. BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1a and 1b are drawings showing the particle shape of the raw material α-alumina (アルミナ -07) in a scanning electron micrograph. FIG. Is the one with a magnification of 500.000.

2a and 2b are drawings showing the particle shape of raw material alumina (AA-2) in a scanning electron micrograph, and FIG. Has an enlargement factor of 500.000.

Figures 3a and 3b are scanning electron micrographs of the raw material α-alumina (原料 -3). 3A is a drawing showing the particle shape, and FIG. 3A is a drawing having a magnification of 2000 times, and FIG. 3B is a drawing having a magnification of 500 times.

FIGS. 4a and 4b are drawings showing the particle shape of raw material alumina (AA-5) in a scanning electron micrograph. FIG. 4a shows the particle shape at a magnification of 2000 times. b has an enlargement factor of 500.000.

FIGS. 5a and 5b are drawings showing the particle shape of the raw material α-alumina (ΑΑ-8) in a scanning electron micrograph, and FIG. b has an enlargement factor of 500.000.

FIGS. 6a and 6b are drawings showing the particle shape of the raw material α-alumina (ΑΑ-10) in a scanning electron micrograph, and FIG. 6b has a magnification of 500.000.

FIGS. 7a and 7b are drawings showing the particle shape of the raw material α-alumina (ΑΑ−18) in a scanning electron micrograph. 7b has a magnification of 500.000.

8a and 8b are drawings showing the particle shape of the raw material α-alumina (RA-40) in a scanning electron micrograph, and FIG. 8a shows the particle shape at a magnification of 2000 times. b has an enlargement factor of 500.000.

Fig. 9a and Fig. 9b show the particle shape of BAT-1 phosphor (using AA-2) by scanning electron microscopy. Fig. 9a shows the one with a magnification of 2000 times. In FIG. 9B, the magnification is 500 ×.

FIGS. 10a and 10b are drawings showing the particle shape of the BAT-2 phosphor (using AA-3) in a scanning electron micrograph, and FIG. In FIG. 10b, the magnification is 5,000 times.

Fig. 11a and Fig. 11b are drawings showing the particle shape of a BAT-3 phosphor (using AA-5) in a scanning electron micrograph. Fig. 11a shows a magnification of 2000. In FIG. 11b, the magnification is 50,000 times.

Fig. 12a and Fig. 12b show the particle shape of the BAT-4 phosphor (using AA-8) in a scanning electron micrograph. Fig. 12a shows the particle size of 20000. In FIG. 12b, the magnification is 500 times. Figures 13a and 13b are drawings showing the particle shape of a BAT-5 phosphor (using AA-10) in a scanning electron micrograph, and Figure 13a shows a magnification of 20%. In FIG. 13B, the magnification is 5,000 times.

Figs. 14a and 14b are drawings showing the particle shape of a BAT-6 phosphor (using AA-18) in a scanning electron micrograph, and Fig. 14a shows a magnification of 20%. In FIG. 14B, the magnification is 0000 times, and the magnification is 50,000 times. · Fig. 15a and Fig. 15b are drawings showing the particle shape of the BAT-REF phosphor (using RA-40) of the comparative example in a scanning electron micrograph, and Fig. 15a shows the magnification. FIG. 15b shows a magnification of 2000 times, and FIG. 15b shows a magnification of 5000 times.

Fig. 16a and Fig. 16b are diagrams showing the particle shape of the aluminate-based phosphor (AA07-127R) by a scanning electron microscope. In FIG. 16b, the magnification is 0000 times, and the magnification is 500 times.

Fig. 17a and Fig. 17b are drawings showing the particle shape of the aluminate-based phosphor (AA30-129R) with a scanning electron microscope. Fig. 17a shows a magnification of 20%. In FIG. 17b, the magnification is 500 times, and the magnification is 500 times.

FIGS. 18a and 18b are drawings showing the particle shape of the aluminate-based phosphor (AA50-130R) by scanning electron microscopy, and FIG. In FIG. 18b, the magnification is 0000 times, and the magnification is 5,000 times.

Fig. 19a and Fig. 19b are drawings showing the particle shape of the aluminate-based phosphor (RA-124R) by scanning electron microscopy, and Fig. 19a shows a magnification of 200 In FIG. 19b, the magnification is 500 times.

FIGS. 20a and 20b show the particle shapes of the comparative phosphor CP-056C30 before crushing with a scanning electron microscope, and FIG. 20a shows a magnification of 2000 times. Fig. 20b shows the case where the magnification is 500 times.

FIGS. 21 a and 21 b are drawings showing the particle shape of a comparative phosphor, CP-05 6C30SS, with a scanning electron microscope, and FIG. 21 a is the one with a magnification of 2000 times. 2 lb is a magnification of 500,000. BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. Various measurements in the present invention were performed as follows.

1. Characterization of α-alumina powder

(1) The primary particle size of the α-alumina powder is 80 to 10.0 particles from the SEM (scanning electron microscope, manufactured by JEOL Ltd .: 300-1) photograph of the α-alumina powder. The children were selected and image analysis was performed, and the average value of the circle equivalent diameter was obtained. The equivalent circle diameter is a value converted into the diameter of a perfect circle having the same area.

(2) The average particle size (D50) and particle size distribution (D90 / D10) of the α-alumina powder were measured using a master sizer (Malvern) based on the laser scattering method. It was measured.

(3) The specific surface area of the a-alumina powder was measured by the BET method.

(4) The purity analysis of α-alumina powder was performed using an emission spectrometer (CQM-75 manufactured by Shimadzu Corporation).

(5) The particle shape of the α-alumina powder was photographed using a scanning electron microscope (manufactured by JEOL Ltd .: 2-220Α).

2. Characterization of aluminate phosphor

(1) The average particle size (D50) and particle size distribution (D90ZD10) of the aluminate-based phosphor were measured using the SK Laser Micron Sizer-1 (manufactured by Seishin Enterprise), which uses the laser scattering method as the measurement principle. It measured using.

(2) The particle shape of the aluminate-based phosphor was photographed by using a scanning electron microscope (manufactured by JEOL Ltd .: 122-OA).

(3) The emission intensity of the aluminate-based phosphor was measured using a fluorescence spectrophotometer (made by Opto Research).

The Hi-Alumina powder having a primary particle diameter of 0.3 m or more and 30 rn or less and having substantially no crushed surface used in this example is sold by Sumitomo Chemical Co., Ltd. under the trade name of Advanced Aluminum. A lot of alumina powder having the characteristics shown in the following Tables 1 and 2 was used. In addition, RA-40 was used as a comparative example. FIGS. 1 to 7 show the particle shape of the raw material α-alumina used in this example in a scanning electron micrograph. FIG. FIG. 8 is a drawing showing the particle shape of a raw material α-alumina used for comparison in a scanning electron micrograph.

Table 1 Primary particle size Average particle size Particle size distribution α-Alumina name D 50

(^ m) (βΐη) D 9 0 / D 1 0

ΑΑ- 0 7 0.6 4 0.6.6 2.5

ΑΑ- 2 1. 7 1. 8 2. 1

ΑΑ- 3 2.8 2. 7 2. 1

ΑΑ- 5 4. 9 4. 7 2.0

ΑΑ- 8 7.5 7.0 0 1.8

ΑΑ— 1 0 9. 8 9. 2 1. 6

ΑΑ- 1 8 1 6 1 5 1. 6

RA-40.0.4 6 2.7 7.0 Table 2 α-Alumina name B ET (m ² / g) Purity (remarks)

ΑΑ- 0 7 2.4> 9 9.9 9 9 Fig. 1

ΑΑ-21.0> 9 9.9 9 9 Fig. 2

ΑΑ- 3 0.7> 9 9. 9 9 Fig. 3

ΑΑ- 5 0.4> 9 9. 9 9 Fig. 4

ΑΑ- 8 0.4> 9 9.9 9 9 Fig. 5

ΑΑ- 1 0 0.4> 9 9.9 Figure 6

ΑΑ- 1 8 0.4> 9 9.9 Figure 7

RA-4 0 3.6> 9 9.99 9 Figure 8

Example 1 (Production of BAT phosphor, no flux added)

Using the following raw materials, a BAT phosphor represented by the chemical formula (Ba ₉ .Euo.!) O.MgO.5 AO: was produced.

Carbonated Barium (B a C〇 ₃ ) /Five"

Europium oxide (Eu ₂ 〇 ₃ )

Basic magnesium carbonate trihydrate (3MgC_〇 _{_{3 'Mg (OH) 2 ·}} 3 H 2 O) α- alumina (a- A 1 ₂ 0 ₃₎

The a-alumina powder includes AA-2 (average particle size 1.8 ^ m, particle size distribution 2.1) and AA-3 (average particle size) sold by Sumitomo Chemical Co., Ltd. under the trade name of Advanced Alumina. Particle size 2.7 m, particle size distribution 2.1), AA-5 (average particle size 4.7 urn, particle size distribution 2.0), AA-8 (average particle size 7.0 ^ m, particle size distribution 1. 8), AA-10 (average particle size 9.2 um, particle size distribution 6), AA-18 (average particle size 15 / m, particle size distribution 6), and RA-40 (average particle size) A diameter of 2.7 urn and a particle size distribution of 7.0) were used.

In the production, the above-mentioned raw materials were sufficiently mixed by a pole mill, and calcined in a reducing atmosphere at 1500 ° C. for 3 hours without flux to obtain a phosphor (burn-up). Further, the obtained phosphor was crushed by a bead mill for 30 minutes to obtain a phosphor (after crushing). In the comparative example (using RA-40), aluminum fluoride was added as a flux (substituting 3% mol of aluminum atoms in mono-alumina) and calcined at 1300 ° C for 3 hours in a reducing atmosphere. The phosphor was obtained (baked). Further, the obtained oxide was pulverized with a bead mill for 60 minutes to obtain a phosphor.

Table 3 shows the results of comparing the average particle diameter, emission peak, and peak intensity of each of the obtained phosphors after baking and crushing. 9 to 14 show the particle shapes of the obtained phosphors in scanning electron micrographs. FIG. 15 is a drawing showing the particle shape of the phosphor of the comparative example in a scanning electron micrograph. As shown in Table 3, the raw material a—Alumina powder was calcined so as not to be melted by the flux, and the primary particle diameter was 0.3 im or more and 30 / m or less and had substantially no crushed surface. -A phosphor with different particle diameters derived from alumina powder was obtained. lb

Table 3

When examining the individual phosphors, comparing the particle shapes of the raw material α-alumina shown in Figs. 2 to 7 and the phosphors shown in Figs. 9 to 14, the particle size of the raw material α-alumina powder was It can be seen that the aluminate-based phosphor having a size derived from the particle diameter of the raw material mono-alumina was obtained without being substantially melted.

However, the measured value of the average particle diameter was about 1.4 to about 13 times the value of the particle diameter of the raw material α-alumina powder. This is due to the adhesion between the obtained phosphors. That is, BAT— :! of the present embodiment. The BAT-5 phosphor is fired as a phosphor having almost no change in the particle diameter of the raw material alumina powder, and is fired in a state where the phosphors are adhered with a small force. For this reason, the crushing is easily separated by a force enough to loosen the adhesion between the particle diameters, and the crushing is easy and the number of fine particles is small. As a result, an aluminate-based phosphor having excellent afterglow characteristics and a high product yield can be easily obtained. Example 2 (manufacture of BAL phosphor, no flux added)

Using the following raw materials, the chemical formula (1.29 (B ao. A, C ao., E u o. I) O · 5.5

Was prepared BAL phosphor represented by A 1 ₂ 0 _3).

Carbonate Bariumu (B a C0 ₃₎ f7

Calcium carbonate (C a CO,)

Europium oxide (Eu ₂ 0 ₃₎

α- alumina (a- A 1 ₂ 0 ₃₎

Note that Hi-Alumina powder includes AA-3 (average particle size 2.7 urn, particle size distribution 2.1) and AA-5 (average particle size) sold by Sumitomo Chemical Co., Ltd. under the trade name of Advanced Alumina. Particle size 4.7 urn, particle size distribution 2.0) and AA-8 (average particle size 7.0 urn, particle size distribution 2.1) were used, and RA-40 (average particle size 2.7 urn, The particle size distribution 7.0) was used.

In the production, the above-mentioned raw materials were sufficiently mixed in a ball mill, and calcined in a reducing atmosphere at 150 ° C. for 3 hours without flux to obtain a phosphor (burn-up). In the comparative example (using RA-40), aluminum fluoride was added as a flux (substituting 3% mol of aluminum atom of a-alumina), and the mixture was heated at 1300 ° C for 3 hours in a reducing atmosphere. Fired. After the obtained oxide was pulverized, this powder was further fired again at 130 ° C. for 3 hours in a reducing atmosphere to obtain a phosphor (burn-up).

Table 4

Table 4 shows the results of comparing the average particle diameter, emission peak, and peak intensity of each of the obtained phosphors after baking. As shown in Table 4, the raw material a—alumina powder was calcined so as not to be melted by the flux, and the primary particle diameter was 0.3 m or more and 30 urn or less and had substantially no crushed surface. Phosphors having different particle diameters derived from alumina powder were obtained. Example 3 (Production of SAE phosphor, no flux added)

Using the following raw materials, chemical formula was prepared SAE phosphor represented by (4 (S r 0. 96, E Uo.. 4) O. 7 A 1 2 0 3).

Strontium carbonate (S r C0 ₃₎

Europium oxide (E u ₂ 〇 ₃₎ ..

α-Alumina (α- A 1 ₂ O 3)

In addition, α-alumina powder is available under the trade name of Advanced Alumina from Sumitomo Chemical Co., Ltd. ΑΑ-3 (average particle size 2.7 xm, particle size distribution 2.1), AA-5 (average particle size Diameter 4.7 fim, particle size distribution 2.0), AA-8 (average particle size 7.0 zm, particle size distribution 2.1) were used, and RA-40 (average particle size 2.7 urn, particle size) The distribution 7.0) was used.

In the production, the above-mentioned raw materials were sufficiently mixed in a ball mill, and calcined in a reducing atmosphere at 150 ° C. for 3 hours without flux to obtain a phosphor (burn-up). In the comparative example (using RA-40), aluminum fluoride was added as a flux (substituting 3% mole of aluminum atom of α-alumina), and 0.20 mole of boric acid was added. It was calcined at 1300 ° C. for 3 hours in a neutral atmosphere. After the obtained oxide was pulverized, it was further fired at 130 ° C. for 3 hours in a reducing atmosphere to obtain a phosphor (burn-up).

) o

Table 5 Baked

α-alumina

Average particle Emission peak

Sanfur name Raw material diameter D50

[/ xm] [nm] [¾]

SAE-REF RA-40 13.0 491 101.2

SAE-1 ΑΑ-3 10.6 491 100.5

SAE-2 ΑΑ-5 13.4 492 98.2

SAE-3 ΑΑ-8 17.7 492 101.8 I

Table 5 shows the results of comparison of the average particle diameter, emission peak, and peak intensity of each of the obtained phosphors after baking. As shown in Table 5, by firing the raw material alumina powder so as not to be melted by the flux, the raw material α-alumina having a primary particle size of 0.3 m or more and 30 im or less and having substantially no crushed surface was obtained. A phosphor having a particle diameter derived from the particle diameter of the powder was obtained. Example 4 (manufacture of CAT phosphor, no flux added)

Using the following raw materials were prepared for CAT phosphor represented by the formula _{((C e .. 65, Tb} «. 35) OL 5 · MgO · 5. 5 A 1 2 O 3).

Oxidation Seriumu (C e 0 ₂₎

Terbium oxide (Tb ₄ 〇 ₇ )

Basic magnesium carbonate trihydrate (3MgC_〇 _{_{3 'Mg (OH) 2 ·}} 3Η 2 Ο) α- alumina _{(ο; - A 1 2 0} 3)

In addition, a-alumina powder includes AA-07 (average particle size 0.66 xm, particle size distribution 2.5) and AA-2 (average particle size) sold by Sumitomo Chemical Co., Ltd. under the trade name of Advanced Alumina. Diameter 1.8; m, particle size distribution 2.1), AA-3 (average particle size 2.7 urn, particle size distribution 2.1), AA-5 (average particle size 4.7 urn, particle size distribution 2) 0), AA-8 (average particle size 7.0 urn, particle size distribution 2.1), AA-10

(Average particle size 9.2ΐ, particle size distribution 1.6) and AΑ-18 (average particle size 15 / xm, particle size distribution 2.1), and RA-40 (average particle size 2. 7 m, particle size distribution 7.0) was used.

In the production, the above-mentioned raw materials were sufficiently mixed in a ball mill, and calcined in a reducing atmosphere at 1500 ° C. for 3 hours without flux to obtain a phosphor (baked). Further, the obtained phosphor was crushed by a bead mill for 30 minutes to obtain a phosphor (after crushing). In addition, comparative example

(Using RA-40), aluminum fluoride was added as flux (substituting 3% mol of aluminum atom of a-alumina), and 0.08 mol of boric acid was added. Firing was performed at ° C for 3 hours. After the obtained oxide was powder-framed, it was further baked at 1300 ° C. for 3 hours in a reducing atmosphere to obtain a phosphor (burn-up). Further, the obtained phosphor was ground by a bead mill for 30 minutes to obtain a phosphor. Table 6

Table 6 shows the results of comparing the average particle diameter, emission peak, and peak intensity of each of the obtained phosphors after baking and crushing. As shown in Table 6, by firing the raw material α-alumina powder so as not to be melted by the flux, the raw material alumina powder having a primary particle diameter of 0.3 to 30 and having substantially no crushed surface was obtained. Phosphors having different particle diameters derived from the powder were obtained. Example 5 (Production of CM Z phosphor, no flux added)

Formula using the following ingredients (C eOu · (Mgo. Z n .. 4., Mn .. 26) 〇 • 5. 5 was prepared CMZ phosphor represented by A 1 ₂ 0 _3.

Cerium oxide (Ce0 ₂₎

Basic magnesium carbonate trihydrate (3MgC_〇 _{3 'Mg (OH) 3 H} 2 〇) zinc carbonate (Z n CO

Manganese carbonate (MnC0 ₃₎

α-alumina (a- A 1 ₂ Os)

The a-alumina powder includes AA-3 (average particle size 2.7 n, particle size distribution 2.1) and AA-5 (average particle size) sold under the trade name of Advanced Alumina by Sumitomo Chemical Co., Ltd. Diameter 4.7 um, particle size distribution 2.0) AA-8 (average particle diameter /

7.0 rn, particle size distribution 2.1) were used, and RA-40 (average particle size 2.7 um, particle size distribution 7.0) was used for comparison.

In the production, the above-mentioned raw materials were sufficiently mixed in a ball mill, and calcined in a reducing atmosphere at 1500 ° C. for 3 hours without flux to obtain a phosphor (baked). Further, the obtained phosphor was unframed in a bead mill for 30 minutes to obtain a phosphor (after crushing). In the comparative example (using RA-40), aluminum fluoride was added as a flux (substituting 3% mol of aluminum atoms of monoalumina), and firing was performed at 1300 ° C for 3 hours in a reducing atmosphere. After the obtained oxide was pulverized, it was further baked at 130 ° C. for 3 hours in a reducing atmosphere to obtain a phosphor (burn-up). Further, the obtained phosphor was powder-framed with a beam mill for 60 minutes to obtain a phosphor.

Table 7

Table 7 shows the results of comparing the average particle diameter, emission peak, and peak intensity of each of the obtained phosphors after baking and crushing. As shown in Table 7, by firing the raw material alumina powder so as not to be melted by the flux, the raw material powder having a primary particle diameter of 0.3 m or more and 30 m or less and having substantially no crushed surface is obtained. Phosphors having different particle diameters derived from alumina powder were obtained. Example 6 (Production of high afterglow acid salt-based phosphor without using flux)

(S r, Eu ...! ., Dy .... 2) firing the O · A 1 ₂ 〇 ₃ aluminate phosphor having afterglow characteristics shown without the addition of flux. The raw materials used Two

It is as follows.

Strontium carbonate (S r C0 _3),

Europium oxide (Eu ₂ 〇 ₃ ),

Dysprosium oxide (Dy ₂ 0 _3),

Facial - alumina powder _{_{(a- A l 2 0 3)}} ,

As α-alumina powder, Hi-Alumina powder A-07, AA-3, AA-5 (trade name “Advanced Alumina”, manufactured by Sumitomo Chemical Co., Ltd.) and RA-40 (Commercially available, manufactured by Iwatani Chemical Industry Co., Ltd.). The average particle size of the raw material α-alumina powder used and the particle size characteristics of the particle size distribution are as shown in Table 8 below.

Table 8

The above-mentioned raw materials were sufficiently mixed in a ball mill, and calcined in a reducing atmosphere at 1300 ° C. for 3 hours, and the obtained oxide was ground in an automatic mortar for 20 minutes to obtain each phosphor. . As a comparative example, a commercially available aluminate-based phosphor CP-056C30 having afterglow properties (commercially available product, trade name “Pikarico” manufactured by Chemitech Co., Ltd.) was ground in an automatic mortar for 120 minutes. CP-05 6C30SS was used.

Table 9 shows the properties of the obtained phosphor, such as the afterglow intensity, and Table 10 shows the average particle diameter and the particle diameter characteristics of the particle size distribution. The afterglow intensity was as follows: CP-056C30 (commercial product, product name “Pikarico”, manufactured by Chemitech Co., Ltd.) was crushed in an automatic mortar for 120 minutes (CP-056C30 SS) as 100%. It is a calculated value. The obtained aluminum having afterglow characteristics The particle shapes of the phosphate-based phosphor with a scanning electron microscope are shown in the substitute photographs in Figs. 16 to 19, respectively. Fig. 21 is a drawing showing the particle shape of the aluminate-based phosphor CP-056C30 having afterglow characteristics as compared to Fig. 20. Fig. 21 shows the particle shape of the phosphor of Fig. 20. A drawing showing the particle shape of the product (CP-05 6C30SS) with a scanning electron microscope is shown.

Table 9.

Table 10

As can be seen by comparing the raw materials shown in Figs. 1, 3, 4, and 15 with the fired products shown in Figs. Add Α-alumina is fired without melting, and the raw material α-alumina powder is not melted, maintains the particle size as it is, and has an afterglow aluminate-based fluorescent light. The body is obtained.

However, comparing Tables 8 and 10, the measured value of the average particle diameter of the obtained aluminate-based phosphor having the afterglow characteristic based on the laser-scattering method is substantially crushed. In the case of using 07-07, ΑΑ-3, A 5-5 without surface and RA-40 with crushed surface, the average particle diameter of α-alumina powder raw material before firing is 0.66 xm ~ The average particle diameter of the obtained aluminate phosphor having afterglow characteristics after firing is 6.4 m to 1 / xm. 0.9; about 13 times to about 2.3 times the average particle diameter of m and the raw material alumina powder.

This can be seen from the comparison of the raw materials shown in Figs. 1, 3, 4, and 15 with the calcined products shown in Figs. If the particle size is small, adjacent particles of a-alumina powder will fuse with each other to form droplet-shaped particles with a primary particle diameter of about several meters, and particles of this fused number; It is fired in the state where it is. In addition, if the particle diameter of the raw material a-alumina powder is large, the particles of the raw material a-alumina powder are maintained without being melted, but the particles adjacent to each other are bonded with a weak force. Fired. Therefore, by crushing with an automatic mortar for about 20 minutes, it is possible to obtain small particles having an average particle diameter of about 10 xm with almost no coarse particles and fine powder.

In contrast, with commercially available aluminate-based phosphors having afterglow characteristics, the 50% average particle size (D50) must be reduced to the same particle size as AA-07, AA-3, and AA-5. Must be sufficiently crushed, and the labor involved in this crushing is enormous. In addition, it is clear that the afterglow intensity is equal to or less than that of the particles having the same particle diameter, and the particle diameter is not uniform and classification is required.

In the case of RA-40, the afterglow intensity was lower than that of a commercially available aluminate-based phosphor having afterglow characteristics. This is because the primary particle diameter of raw material a-alumina is 0.46 m, which is much smaller than other particle diameters, and the average particle diameter of the obtained phosphor is also much smaller, 6.4 zm. Commercially available aluminate with afterglow properties It is important to compare salt phosphors with an average particle diameter of about RA-40. However, milling of aluminate phosphors with afterglow properties that are commercially available to about 6.4 m is virtually impossible. Impossible.

As described above, the aluminate-based phosphor having the afterglow characteristic according to the present invention exhibits a high afterglow intensity despite the small average particle diameter, and the aluminate-based phosphor having extremely excellent afterglow characteristics A phosphor can be obtained. .

In the present _{embodiment, (S r, Euo .. 10} , Dy 0 .. 02) has shown an example of O · A 1 ₂ 0 ₃ phosphor, the general _{_{formula; aMO 'A l 2 0 3}} ( where , M is a compound consisting of at least one metal element selected from the group consisting of strontium (Sr), calcium (Ca), and barium (Ba), and a is 0.5 to 1.1) Europium (Eu) was added as an activator to the composite oxide substrate represented by the above in an amount of 0.002% or more and 20% or less in terms of mol% based on the metal element represented by M. Further, as a coactivator, , Cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), At least one element in the group consisting of ytterbium (Yb), lutetium (Lu), and scandium (Sc) is represented by M Aluminate-based phosphor having afterglow properties added in an amount of 0.002% or more and 20% or less in terms of mol% based on a metal element, and a general formula; (Sr, Eu, Pb, Dy) O A 1, B i) ₂ 〇 ₃ (0.83≤y≤ l. 67) Eulan ⁺ -activated strontium-aluminate-based phosphorescent aluminate By firing without using a flux, an aluminate-based phosphor having fine afterglow characteristics derived from the raw material alumina powder can also be obtained.

Claims

The scope of the claims

1. In the synthesis of aluminate-based phosphor,

As the raw material alumina, α-alumina powder having a primary particle diameter of 0.3 or more and 30 m or less and having substantially no crushed surface was used

A method for producing an aluminate-based phosphor, characterized in that when firing after mixing each raw material, the raw material alumina powder is fired without being melted by flux.

2. The aluminate-based phosphor has the general formula

Mi is at least one metal element selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca);

The method for producing an aluminate-based phosphor according to claim 1, wherein a is in the range of 0.5 to 4.5, b is in the range of 0 to 4, and c is in the range of 0.5 to 20.

3. Aluminate phosphor is a general formula

Is a compound in which an activator composed of terbium (Tb) and phosphorus or manganese (Mn) is added to the composite oxide substrate represented by

M ₂ is at least one metal element selected from magnesium (Mg) and zinc (Zn),

2. The method for producing an aluminate-based phosphor according to claim 1, wherein d is 0.9 to 1.1, e is 0.9 to 1.1, and f is 5.5.

4. The aluminate-based phosphor has the general formula

hM ₃ 〇A 12 O 3

(M ₃ strontium (S r), calcium (C a;), or the group consisting of barium (B a) 7

Et compounds comprising at least one or more metal element selected, h is the composite oxide substrate represented by 0.5 1.1) mol% of europium as the activator (E u) is for metallic elements represented by M ₃ 0.002% or more and 20% or less, and lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), gadolinium (Gd) , Terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er;), thulium (Tm), ytterbium. (Yb), lutetium (Lu), manganese (Mn), tin (Sn), bismuth (B i), aluminates having a scandium © beam (S c) at least one or more elements afterglow characteristic which are added 0.002% or more and 20% or less in terms of mol% relative to the metal element expressed by M ₃ in the group consisting of The phosphor according to claim 1, wherein Method for producing Rumin based phosphor.

5. The aluminate phosphor has the general formula

hMaOA 1 ₂ 0 ₃

Further, at least one metal element selected from lead (Pb), zinc (Zn), and bismuth (Bi) was added to the composite oxide substrate represented by

5. The method for producing an aluminate-based phosphor according to claim 4, wherein:

6. The aluminate-based phosphor has a general formula;

(Sr, Eu, Pb, Dy) O'y (A1, Bi) 2O3

(However, 0.83≤y≤1.67)

2. An aluminate phosphor having an afterglow characteristic according to claim 1, wherein the aluminate phosphor has an afterglow characteristic based on a Eu2 ⁺ -activated strontium-aluminate phosphor represented by the formula: A method for producing a salt phosphor.

7. The aluminate-based phosphor has a general formula;

(S r, Eu, Dy) 0 'A l ₂ 〇 ₃

A method for producing an aluminate-based phosphor having an afterglow characteristic, characterized in that the aluminate-based phosphor has an afterglow characteristic shown in (1). Two

8. The α-alumina powder having a primary particle size of 0.3 / zm or more and 30 / zm or less and having substantially no crushed surface, characterized by using alumina having a purity of 99.9% by weight or more. A method for producing an aluminate-based phosphor according to claim 1.