JP2002212549A - Method for producing fluorescent substance and production apparatus used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method by which a high-intensity high- performance fluorescent substance can be produced with excellent production efficiency. SOLUTION: The fluorescent substance is produced by filling an air-tight container 1 having the inner wall covered with an insulating material made of a heat-resistant fiber, and a graphite heater 8 arranged in the interior space, with a reducing atmosphere 9, placing a heat-resistant container 6 filled with a raw material powder 7 for the fluorescent substance on a rail 8 arranged in the air-tight container 1, sending the heat-resistant container 6 into the air- tight container 1, and firing the raw material powder 7 for the fluorescent substance. The raw material powder for the fluorescent substance preferably contains an aluminum compound to provide an aluminate fluorescent substance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a phosphor and a production apparatus used for the same, and more particularly, to a method for producing a phosphor used as a phosphor for a three-wavelength band fluorescent lamp, a plasma display panel, an electron tube and the like. It relates to a manufacturing method.

[0002]

2. Description of the Related Art Conventionally, as a phosphor material for a three-wavelength band fluorescent lamp, for example, a material that emits blue light, blue green light, green light, or the like, is BaMgAl ₁₀ O ₁₇ :
Eu ²⁺ (blue), (Ba, Sr) MgAl ₁₀ O ₁₇ : E
Aluminate phosphors such as u ²⁺ , Mn ²⁺ (blue-green), Sr ₄ Al ₁₄ O ₂₅ : Eu ²⁺ (blue-green), and CeMgAl ₁₁ O ₁₉ : Tb ³⁺ (green) are used. . As a phosphor for a plasma display, for example, a material that emits blue light, green light, or the like, is BaMgAl ₁₀ O ₁₇ : Eu.
An aluminate phosphor such as ²⁺ (blue) and BaAl ₁₂ O ₁₉ : Mn ²⁺ (green) is used. As a phosphor for an electron tube, for example, Y ₃ Al ₅ O ₁₂ : Tb ³⁺ (green) ) Etc. are used. In addition, as long afterglow phosphors, for example, CaAl ₂ O ₄ : Eu ²⁺ , Nd ³⁺ (blue),
Aluminate phosphors such as SrAl ₂ O ₄ : Eu ²⁺ , Dy ³⁺ (blue-green) are known.

[0003] Aluminate phosphors used for various applications as described above are expected to have improved luminous brightness and luminous performance. For example, a phosphor material containing no fluorine-based substance as a reaction accelerator is used. A method of firing powder in a reducing atmosphere at a high temperature of 1600 to 2000 ° C. is disclosed in JP-A-9-15.
No. 1372. According to this method,
For example, to contain spherical or substantially spherical alumina as a part of the phosphor raw material powder, and to fire without using the reaction accelerator, derived from the particle shape of the alumina raw material,
A spherical or substantially spherical particle-shaped aluminate phosphor is obtained.

In the production of such a conventional aluminate phosphor, a very common high-temperature furnace for burning a phosphor is used. In the high-temperature furnace, for example, a furnace tube made of a material mainly composed of alumina is arranged in a cavity surrounded by a heat-insulating material made of a heat-resistant brick such as porous alumina, and a space between the furnace tube and the heat insulating material is provided. In this configuration, a molybdenum disilicide heater having a maximum heat generation temperature of 1900 ° C. is arranged in the atmosphere. In addition, in the case of a high-temperature furnace for mass production, the furnace tube generally has a structure in which brick-like heat-resistant ceramics made of high-purity alumina having a purity of 98% or more are laminated, and a heat-resistant paste is filled in voids of the laminate. The inside of the core tube is kept airtight. Incidentally, when the molybdenum disilicide heater is electrically heated in a reducing atmosphere,
Since it has the property of weakening, it has a structure that generates heat in the atmosphere of an oxidizing atmosphere.

Conventionally, when the aluminate phosphor is fired, the inside of the furnace tube is filled with a nitrogen-hydrogen mixed gas to form a reducing atmosphere, and an alumina heat-resistant container filled with a phosphor raw material powder. Is placed, and the alumina heat-resistant container is pushed in another alumina heat-resistant container to be conveyed in a reducing atmosphere, and the phosphor raw material powder is heated at a high temperature of 1600 to 2000 ° C. for a predetermined time and fired. Attempts have been made to do so. Most of the aluminate phosphors are oxidized in the atmosphere, and the brightness tends to decrease and the performance tends to deteriorate.Therefore, the inside of the core tube having the airtight structure as described above is filled with a reducing atmosphere. By firing the phosphor raw material powder in this atmosphere, it is possible to achieve high luminance and high performance of the phosphor. In addition, the firing temperature of the aluminate phosphor has been increasing with the demand for higher performance of the phosphor. Particularly, as disclosed in JP-A-9-151372, as a part of the phosphor raw material powder, a particulate (for example, spherical, substantially spherical, plate-like, etc.) alumina is contained, and a reaction accelerator is used. In the method of producing aluminate phosphor having a shape derived from the particle shape of the alumina raw material by firing without using
High temperature processing at 2000 ° C., preferably 1650 to 1850 ° C., is required.

[0006]

However, as the firing temperature set as described above is increased, the following problems occur. For example, if the furnace temperature is set to a normal phosphor firing temperature of 1000 to 1400 ° C.,
Since the temperature is as high as 1600 to 2000 ° C. as compared with 50 ° C., deterioration and cracking of the furnace tube due to thermal shock, cracking of the heat insulating material, heater consumption and disconnection due to high temperature use may be severe. Further, compared with the case of firing at the normal firing temperature, even a half of the furnace life could not be ensured, and it was extremely difficult to perform long-term continuous firing for several months or more. In addition, since an alumina furnace tube formed of heat-resistant ceramics that is weak to thermal shock is used, the furnace tube is damaged, and it is difficult to maintain a reducing atmosphere during firing, and the heating temperature of the firing furnace is raised or lowered by 200 ° C. or more. Is difficult, and
It was also difficult to repeatedly start and stop the firing furnace.

[0007] For this reason, for example, although it is possible to fire a small amount of aluminate phosphor of several kg or less in a single shot, it is not possible to perform long-term continuous firing for mass production. There is a problem that the quality of the phosphoric acid salt varies greatly. In addition, even if an attempt is made to produce a plurality of types of aluminate phosphors having different optimum firing temperatures, it is difficult to raise or lower the heating temperature as described above. However, there is also a problem that the production cannot be performed at the respective optimum firing temperatures using the same firing furnace. In addition, even if the order quantity of the aluminate phosphor is reduced and the supply of the phosphor raw material powder is stopped and temporarily stopped, the furnace tube is damaged if the firing furnace is stopped for a certain period of time. However, there was also a problem that operating costs were high.

Therefore, an object of the present invention is to provide a high-brightness, high-performance phosphor that can be continuously processed in large quantities with stable quality and excellent production efficiency, raising and lowering the heating temperature and starting the firing furnace.
An object of the present invention is to provide a method of manufacturing a phosphor that can be easily stopped and a manufacturing apparatus used for the method.

[0009]

Means for Solving the Problems In order to solve the above problems, a method for producing a phosphor of the present invention is a method for producing a phosphor, wherein an inner wall of the phosphor is covered with a heat-resistant fiber heat insulating material, and an inner space is formed. Is characterized in that a heat-resistant tray on which a phosphor material powder is placed is carried into an airtight container in which a graphite heater is arranged, and the phosphor material powder is fired in a reducing atmosphere.

As described above, the present invention first uses a heater composed of graphite (carbon).
For example, it can withstand long-term use at a high temperature, particularly 1600 to 2000 ° C., and short-term consumption of the heater and occurrence of disconnection can be prevented. Further, since a heat-resistant fiber heat insulating material is used as a heat insulating material for covering the inner wall of the hermetic container, thermal shock does not become a problem at all, for example, high-temperature sintering as described above, or an increase or decrease in heating temperature, Cracking or breakage of the heat insulating material is prevented. Furthermore, the present invention does not maintain the reducing atmosphere tightly by using a brick-shaped alumina core tube or the like which is easily damaged by a thermal shock or the like such as raising or lowering the temperature as in the conventional manufacturing method. . For this reason, the problem that the reducing atmosphere cannot be maintained due to the damage of the alumina core tube is avoided, and for example, the cost of the apparatus and the maintenance frequency can be reduced.
From the above, according to the production method of the present invention, it is possible to carry the phosphor raw material powder into the hermetic container filled with the reducing atmosphere in a long term, and to stably perform the high-temperature firing operation. become able to. Further, for example, even if the firing temperature is changed or the production is started and stopped repeatedly,
Production can be performed stably. Therefore, for example, it can be said that this is a manufacturing method suitable for mass production of phosphors and improvement of production efficiency.

In the production method of the present invention, the phosphor raw material powder preferably contains an aluminum compound,
The phosphor produced is preferably an aluminate phosphor. In the present invention, the “aluminate phosphor” refers to a phosphor containing an aluminum compound and oxygen as main elements.

In the manufacturing method of the present invention, it is preferable that the shape of the aluminum compound is the same or substantially the same as the shape of a desired phosphor. By setting the shape of the aluminum compound in this way, an aluminate phosphor having a shape derived from the shape of the aluminum compound can be obtained.
Continuous mass production with stable quality and excellent production efficiency is possible. In the case where the shape of the phosphor is set in this way, it is preferable to perform firing without adding a reaction accelerator as described later, since the shape of the aluminum compound is easily maintained.

In the production method of the present invention, the shape of the aluminum compound may be spherical, substantially spherical, plate-like, hexagonal plate-like,
The shape is preferably at least one selected from the group consisting of needles, particles, and particles, and is more preferably spherical or substantially spherical.

In the manufacturing method of the present invention, it is preferable that the heat-resistant tray is continuously loaded into the airtight container, and the phosphor raw material powder is fired for each of the loaded heat-resistant trays. As described above, by continuously loading the heat-resistant tray, a longer-term manufacturing can be continuously performed, and a manufacturing method suitable for mass production and improvement of production efficiency can be obtained.

In the production method of the present invention, it is preferable that the phosphor raw material powder is filled in a heat-resistant container, and the heat-resistant container is placed on the heat-resistant tray and carried into the airtight container. In this case, the frequency of direct handling of the heat-resistant container filled with the phosphor material is reduced, and contact and collision between the heat-resistant containers can be prevented, so that the device can be used for a long time.

In the production method of the present invention, the airtight container further includes a graphite core tube therein.
Preferably, the phosphor raw material powder is fired in a reducing atmosphere inside the graphite core tube.

When the phosphor is fired, for example, an oxidizing gas (including water and carbon dioxide) is generated from the phosphor raw material powder, and the heater and the heat insulating material may be consumed by the oxidizing gas. However, as described above, if a graphite core tube resistant to thermal shock is further disposed in the hermetic container, and sintering is performed inside the furnace tube, the heat-resistant fiber heat insulating material disposed on the inner wall of the hermetic container becomes oxidizable. Exposure to gas or the like can be prevented. Therefore, as described above, it is possible to suppress not only deterioration due to thermal shock such as high-temperature heating, but also deterioration due to the oxidizing gas and the like, which is more suitable for mass production of phosphors and improvement of production efficiency. It can be a manufacturing method. Further, since the deterioration of each component can be further prevented, the cost can be further reduced.

In the manufacturing method of the present invention, the heat insulating material made of heat-resistant fiber is made of graphite, alumina, magnesia, zirconia, hafnia, titania, aluminum nitride, titanium nitride, vanadium nitride, zirconium nitride, boron nitride, hafnium nitride, tantalum nitride. , Boron carbide, molybdenum carbide, silicon carbide, tungsten carbide, hafnium carbide, niobium carbide, tantalum carbide, titanium carbide,
Fibers composed of materials such as zirconium carbide, aluminum boride, titanium boride, vanadium boride, tungsten boride, hafnium boride, zirconium boride, metal hafnium, metal iridium, metal molybdenum, metal niobium, metal tantalum and metal tungsten It is preferably composed of a body, more preferably graphite, alumina, magnesia, and zirconia, and particularly preferably graphite. The fibrous body may be, for example, any one type, or may be formed from two or more types of substances. Further, the heat insulating material may be formed of, for example, one kind of fibrous body, or may be formed of two or more kinds of fibrous bodies.

As the heat insulating material made of heat-resistant fiber, for example, a heat-resistant fiber press-formed body or a fiber board obtained by press-molding the heat-resistant fiber body can be used.

In the production method of the present invention, the method of loading the phosphor raw material powder into the hermetic container includes, for example,
The following methods are available.

As a first method, for example, the airtight container has a rail passing through the inside of the heat-resistant tray along the carrying direction of the heat-resistant tray, and a plurality of the heat-resistant trays are mounted on the rail. It is preferable that the heat-resistant tray positioned forward is pushed by the heat-resistant tray that is arranged and positioned rearward in the loading direction to move the heat-resistant tray and load the heat-resistant tray.

As a second method, for example, the airtight container has a rail penetrating therethrough along the carrying direction of the heat-resistant tray, and the heat-resistant tray is placed on the rail. Preferably, the heat-resistant tray is carried in by being disposed and the rail moving in the carrying-in direction. Note that “moving in the carrying-in direction” refers to moving from the carrying-in side to the carrying-out side.

In the production method of the present invention, the airtight container is preferably a metal container, and the material is preferably, for example, stainless steel, iron, aluminum, copper, nickel or the like. The metal may be, for example, one type or two or more types.

In the production method of the present invention, the sintering temperature is
It is preferably in the range of 1600 to 2000 ° C,
Since the present invention is a production method particularly useful for baking in a high temperature state, the temperature is more preferably in the range of 1650 to 1850 ° C, and particularly preferably in the range of 1700 to 1800 ° C.

In the production method of the present invention, the firing time is
For example, it is preferably in the range of 0.1 to 50 hours per heat-resistant tray, more preferably in the range of 0.5 to 10 hours, and particularly preferably in the range of 1 to 5 hours. Further, since the production method of the present invention is useful, for example, when producing a phosphor by continuously operating, the continuous operation time is preferably in the range of 1 to 10,000 hours, more preferably 1 to 400 days. And particularly preferably 1
The range is from 0 to 200 days.

In the production method of the present invention, the phosphor raw material powder preferably contains an aluminum compound in a range of 40 to 90% by weight, more preferably 50 to 80% by weight, and particularly preferably 60 to 80% by weight. It is in the range of 70% by weight.

Next, the manufacturing apparatus used for manufacturing the phosphor of the present invention includes a cylindrical container having openings at both ends, a graphite heater and rails, one of the two openings being a carry-in port and the other being a carry-in port. A rail is disposed inside the container so as to become an exit and penetrates the carry-in and the carry-out, and each of the openings has an openable and closable shutter that makes the inside of the container airtight when closed. Provided,
The inner wall of the container is covered with a heat-resistant fiber heat insulating material.

As described above, the manufacturing apparatus of the present invention uses a graphite heater, a heat-resistant fiber heat insulating material, and the like.
Since the alumina furnace tube is not used unlike the conventional apparatus, there is no possibility of breakage even when the apparatus is used for a long time at a high temperature, repeated start-stop of the apparatus, or raising and lowering the firing temperature. Therefore, according to the manufacturing apparatus of the present invention, for example, mass production by continuous operation, improvement of production efficiency, cost reduction, reduction of maintenance frequency, and the like can be performed. Therefore, such a production apparatus of the present invention is preferably used in the production method of the present invention, and is particularly preferably used in a production method of an aluminate phosphor.

In the production apparatus of the present invention, it is preferable that a graphite core tube is further disposed inside the vessel, and the rail is disposed inside the graphite core tube. With such a configuration, as described above, deterioration of the device can be further prevented.

In the manufacturing apparatus of the present invention, the heat-resistant fiber heat insulating material may be the same as described above, and is preferably graphite, alumina, magnesia, or zirconia, and more preferably graphite.

In the manufacturing apparatus of the present invention, it is preferable that a front chamber is arranged adjacent to the carry-in port, and a rear chamber is arranged adjacent to the carry-out port. As described above, if the front chamber and the rear chamber are provided adjacent to both the opening portions of the container, by setting them to the same reducing atmosphere as the container, when the heat-resistant tray is loaded or unloaded into the container, Even if the opening is opened, the airtightness in the container can be further maintained.

Since the production apparatus of the present invention is useful, for example, when producing a phosphor by operating continuously, the continuous operation time is preferably in the range of 1 to 10,000 hours, more preferably 1 to 400 hours. Days, particularly preferably from 10 to 200 days.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for producing a phosphor of the present invention will be described in detail with reference to the drawings, in which an example of producing an aluminate phosphor is described. Note that the present invention is not limited to the following embodiments.

(Embodiment 1) FIGS. 1 to 3 show an example of a manufacturing apparatus used in the manufacturing method of the present invention. 1 is a cross-sectional view of the manufacturing apparatus as viewed from the front, FIG. 2 is a cross-sectional view of the manufacturing apparatus as viewed from above, and FIG. 3 is a cross-sectional view of the manufacturing apparatus as viewed from the side. As shown,
The manufacturing apparatus includes an airtight container (hereinafter, also referred to as a “firing furnace”) 1 having a rectangular tubular main body 2, a heat insulating material 4 made of heat-resistant fiber, a graphite heater 3, and rails 8.

The rectangular tubular main body 2 has openings at both ends, and a front chamber 11 and a rear chamber 12 are provided adjacent to each other so as to close the openings. The front chamber 11 and the rear chamber 12 are provided with shutters 13b and 13c which can be freely opened and closed on the side surfaces corresponding to both openings of the rectangular tubular main body 2, respectively. These shutters 13b, 13
By closing c, the airtight container 1 with airtightness is maintained, and by opening the shutters 13b and 13c, one of the openings becomes a carry-in port and the other becomes a carry-out port. In the front room 11 and the rear room 12, shutters 13a and 13d which can be opened and closed are provided on the side surfaces corresponding to the shutters 13b and 13c, respectively. A heat insulating material 4 made of heat-resistant fiber is arranged on the inner wall of the airtight container 1. Above and below the airtight container 1, a plurality of graphite heaters 3 are arranged in parallel in the width direction at regular intervals from the upper surface and the bottom surface of the inner wall. A rail 8 is disposed above the graphite heater 3 disposed on the bottom side, and the rail 8 has protrusions at both ends in the width direction. Due to this convex portion, even if the heat-resistant tray 5 is placed on the rail 8 at the time of use, this does not protrude from the rail 8. Further, inside the airtight container 1, a gradual tropical zone, a heating zone, a gradual cooling zone, and a cooling zone (all not shown) are formed in this order along the direction of arrow A shown in FIGS. ,
The temperature changes continuously in accordance with the location of the graphite heater 3. In this embodiment, the center of the inside of the airtight container 1 provided with the graphite heater 3 is a heating zone. As will be described later, when used, the heat-resistant container 6 filled with the phosphor raw material powder 7 is covered with the lid 10 and placed on the heat-resistant tray 5, and the heat-resistant tray 5 is arranged on the rail 7.

The rectangular cylindrical body 2 is for maintaining the inside of the airtight container 1 in a reducing atmosphere 9 and, as described above, is made of, for example, a metal container of stainless steel, iron, aluminum, copper, nickel or the like. Preferably, it is constituted, more preferably, stainless steel or iron, and particularly preferably, stainless steel.

When a container having such an excellent airtightness is used, the inside of the airtight container 1 is sufficiently airtight, so that the reducing atmosphere 9 filled therein can be sufficiently maintained. Accordingly, for example, the graphite heater 3 that may be oxidized and weakened does not deteriorate due to oxidation. In addition, the heat generated by the graphite heater 3 causes the central portion of the hermetic container 1 to move, for example, to 1600 under a reducing atmosphere.
It is also possible to maintain a high temperature of ２０００2000 ° C. for a long time. At the time of production, a chemical reaction of the phosphor raw material powder can be performed in a state where the reducing atmosphere is sufficiently maintained, so that a high-luminance and high-performance aluminate phosphor can be produced.

In the present invention, the shape, size and the like of the rectangular tubular main body 2 are not particularly limited. For example, the height is in the range of 10 to 100 cm, the width is in the range of 10 to 100 cm, and the depth is long. It is in the range of 1 to 50 m.

The heat-insulating material 4 made of heat-resistant fiber insulates between the graphite heater 3 and the airtight container 1 and prevents melting and abnormal heating of the airtight container 1 due to heat generated by the graphite heater 3. For example, when the firing temperature is set to a high temperature of 1600 to 2000 ° C., it is preferable that the fiber is formed from a heat-resistant fibrous body that can withstand this. As the material of the heat-resistant fiber, for example, graphite, alumina, magnesia, zirconia, hafnia, titania, aluminum nitride, titanium nitride, vanadium nitride, zirconium nitride, boron nitride, hafnium nitride, tantalum nitride, boron carbide, molybdenum carbide, Silicon carbide, tungsten carbide, hafnium carbide, niobium carbide, tantalum carbide, titanium carbide, zirconium carbide, aluminum boride, titanium boride, vanadium boride, tungsten boride,
Preferred are hafnium boride, zirconium boride, metal hafnium, metal iridium, metal molybdenum, metal niobium, metal tantalum, metal tungsten, and the like, more preferably graphite, alumina, magnesia, and zirconia, and particularly preferably graphite.

Since the heat insulating material 4 made of a heat-resistant fiber is made of a fibrous body, it does not cause any problem such as thermal shock and does not break even at a high temperature of, for example, 1600 to 2000 ° C. It will not be damaged by a sudden rise or fall in temperature. In the present invention, in order to use a heat insulating material formed from such a heat-resistant fibrous body, it is possible to perform firing for a long period of several months or more under the above-mentioned high temperature conditions, or to start and stop the firing furnace 1. Even if intermittent baking is performed, the heat insulating material will not be damaged.

The thickness of the heat-resistant fiber heat insulating material 4 is not particularly limited, but is preferably in the range of 30 to 150 mm, more preferably 50 to 150 mm, for example, because it is as thin and inexpensive as possible within the range showing the heat insulating effect. The range is 100 mm. Further, as the heat insulating material 4 made of heat-resistant fiber, a pressure-formed body of the above-described heat-resistant fiber can also be used.
It can be manufactured by press molding under the conditions of g / m ³ and processing time of 1 to 100 minutes. Specifically, when the fibrous body is a graphite fiber, for example, a pressure of 100 to 200 k
The pressure treatment may be performed under the conditions of g / m ³ and a treatment time of 1 to 60 minutes.

The graphite heater 3 is a heating element for heating the phosphor raw material powder 7 for the purpose of synthesizing a desired aluminate phosphor.
It generates heat at a high temperature of 00 ° C. This graphite heater 3
As shown in FIG. 1, are installed on the upper surface side and the lower surface side of the inside of the firing furnace 1 covered with the heat insulating material 4 made of heat-resistant fiber, respectively.
When the heating zone is set to generate heat, the center of the space in the firing furnace 1, that is, a heating zone (not shown) is heated to a temperature of 1600 to 1600 which is suitable for manufacturing a high-luminance and high-performance aluminate phosphor.
It can be set to 2000 ° C. Further, the graphite heater 3 may be one whose surface is coated with a heat-resistant material such as boron nitride or silicon carbide in order to enhance the durability. The shape and dimensions of the graphite heater 3 and the manner of arrangement in the firing furnace 1 are not particularly limited.

The tray 5 is for placing, for example, a heat-resistant container 6 filled with the phosphor raw material powder as it is or with the phosphor raw material powder 7. The material is not particularly limited as long as it can withstand the set firing temperature,
For example, it can be appropriately determined according to the configuration of the firing furnace, the firing temperature, and the like. Specifically, for example, when the firing temperature is set to a high temperature of 1600 to 2000 ° C., it is preferable that the material be able to withstand the firing temperature, such as a high melting point inorganic compound such as alumina, magnesia, and zirconia, and platinum, tungsten, and molybdenum. And other high melting point metals, graphite, silicon carbide, and the like. Among these, alumina, zirconia, and graphite (graphite) are preferable.
It can be used in a high-temperature reducing atmosphere of 00 ° C or more, is inexpensive,
Graphite is particularly preferred because it is resistant to thermal shock and easy to process. The graphite tray may be, for example, a tray whose surface is coated with boron nitride or silicon carbide. By coating in this manner, it is possible to suppress the reaction between the oxidizing gas generated from the phosphor raw material or the hydrogen gas in the reducing atmosphere and the graphite, and further prevent the tray from deteriorating. The thickness of the coating layer is, for example, in the range of 1 to 1000 μm.

As described above, the heat-resistant container 6 filled with the phosphor raw material powder is placed on the tray 5 which is excellent in heat resistance and thermal shock resistance. By pressing and sliding on the rail 8, the phosphor raw material powder 7 can be continuously conveyed. In this case, the heat-resistant containers 6 do not come into contact with each other, and no external physical force is applied to the heat-resistant container 6 being transported, so that damage to the heat-resistant container 6 can be prevented.

The shape of the tray 5 is not particularly limited, and can be appropriately determined according to, for example, the specification of the firing furnace 1, the shape of the rail 8, the shape of a heat-resistant container for filling the raw materials, and the like. A square plate shape and the like can be given. In addition to this, for example, a container having a box shape, a crucible shape with a lid, a box shape with a bottom, a cylindrical shape with a bottom, or the like can be used as the tray 5.

The heat-resistant container 6 is a heat-resistant container for charging a phosphor raw material powder 7 prepared and mixed with materials necessary for obtaining a desired aluminate phosphor. The material is not particularly limited as long as it can withstand the set firing temperature, and can be appropriately determined depending on, for example, the configuration of the firing furnace and the firing temperature. Further, the present invention provides, for example, 1600 to 20
Since it is particularly useful when baking at a high temperature of 00 ° C., it is preferable to use a heat-resistant material that can withstand use under the above-mentioned temperature conditions, similarly to the tray 5 described above. Specifically, for example, high melting point inorganic compounds such as alumina, magnesia, and zirconia, sintered bodies thereof, high melting point metals such as platinum, tungsten, and molybdenum, graphite, and silicon carbide can be used. Among these, for example, a high-purity alumina sintered body is preferable because it does not stain the aluminate phosphor after firing and is easily available. When the material of the heat-resistant container 6 is made the same as that of a part of the aluminate phosphor raw material, for example, there is no possibility that an impurity element is mixed into the aluminate phosphor obtained after firing, so that a high-purity fluorescent material is obtained. The body is obtained and shows high brightness and high performance. In the case of a heat-resistant container made of graphite, for example, a container whose surface is coated with boron nitride, silicon carbide or the like can be used.

The shape and the like of the heat-resistant container 6 are not particularly limited.
For example, it is possible to select a convenient shape or a shape having strong thermal shock resistance from a square shape or a crucible shape. In addition, the heat-resistant container 6 may not have a lid. For example, a phosphor having a higher purity can be obtained by preventing a trace amount of carbon soot and the like which may be generated by baking, from being mixed. It is preferred to have a rating of 10.

The rail 8 moves the tray 5 on which the heat-resistant container 6 filled with the phosphor raw material powder 7 is placed in the direction of arrow A in FIG. 2 and FIG.
This is for sequentially passing through a slow cooling zone and a cooling zone (neither is shown). If such a rail 8 is provided, for example, by pushing the first tray that has been previously loaded into the firing furnace 1 forward with the next second tray,
The first tray slides on the rail 8 and moves forward. In this way, by sequentially pushing the plurality of trays into the firing furnace 1, the trays are connected in a daisy chain and pass through the inside. As a result, the phosphor raw material powders 7 filled in the plurality of heat-resistant containers 6 are continuously heated and reacted, and aluminate phosphors are generated one after another, so that continuous mass production becomes possible.

As described above, when the tray 5 moves on the rail 8, the friction between the rail 8 and the tray 5 is reduced, and the sliding property of the tray 5 that slides on the rail 8 is improved. It is preferable to make the transfer of the tray 5 smooth. Further, the rail is constituted by a plurality of rollers, or a hemispherical dent is provided on the surface of the rail 8, and a ball made of a heat-resistant material is arranged in the dent, and the ball rotates in the dent. It may be constituted by a plate as described above. According to such a configuration, for example, with the rotation of the roller or the rotation of the ball, the tray 5 placed thereon can be easily conveyed. On the other hand, instead of moving the tray on the rail 8, as the rail, for example,
The tray 5 may be automatically transferred by moving the rail itself using a transfer device such as a conveyor.

The material of the rail 8 is not particularly limited as long as it can withstand the heating conditions in the reducing atmosphere as described above. For example, a material that can withstand the high firing temperature of 1600 to 2000 ° C. is preferable. , Graphite, magnesia, zirconia, hafnia, titania, aluminum nitride, titanium nitride, vanadium nitride, zirconium nitride, boron nitride, hafnium nitride, tantalum nitride, boron carbide, molybdenum carbide, silicon carbide, tungsten carbide, hafnium carbide, niobium carbide, Tantalum carbide, titanium carbide, zirconium carbide, aluminum boride, titanium boride, vanadium boride, tungsten boride, hafnium boride, zirconium boride, metal hafnium, metal iridium, metal molybdenum, metal niobium, metal tantalum And metal tungsten, and the like. Among these, graphite is preferable because it can be used under high temperature conditions of 2000 ° C. or more, is inexpensive, is easy to process, and has excellent thermal shock. In the case of a graphite rail, for example, a rail whose surface is coated with boron nitride, silicon carbide, or the like can be used.

The transfer speed of the tray 5 on the rail 8 is not particularly limited, and can be appropriately determined depending on, for example, the firing conditions and the length of the heating zone in the airtight container. It is not limited.

The front chamber 11 and the rear chamber 12 provided with the shutters 13a, 13b, 13c and 13d are disposed adjacent to the rectangular cylindrical body 2 as described above, so that the rectangular cylindrical body 2 is airtight. The container 1 is also used as an airtight chamber in which the tray 5 is temporarily placed. As the material, for example, the same material as the material of the above-described rectangular tubular main body can be used, and the material of the shutter is also the same.

The size of the front chamber and the rear chamber is not particularly limited, but is, for example, in the range of 10 to 100 cm in height and 10 in width.
It is in a range of １００100 cm and a depth of 10-100 cm.

Using this manufacturing apparatus, for example, an aluminate phosphor can be manufactured as follows.

First, a phosphor raw material powder 7 is prepared and filled in a heat-resistant container 6. As the phosphor material, for example, aluminum oxide, aluminum hydroxide, aluminum nitrate, aluminum compounds such as aluminum sulfate,
Alkaline earth metal compounds such as barium carbonate and strontium carbonate, rare earth compounds such as europium oxide, cerium oxide, terbium oxide, cerium fluoride, europium fluoride, lanthanum phosphate, magnesium compounds such as basic magnesium carbonate, manganese carbonate and the like A manganese compound,
And zinc compounds such as zinc oxide. These raw materials may be used alone or in combination of two or more.
The addition ratio can also be appropriately determined according to the type of the desired aluminate phosphor to be manufactured.

Most of the particles of the phosphor raw material may have, for example, a spherical shape, a substantially spherical shape, a plate shape, a hexagonal plate shape, a needle shape, a particle shape, a fine powder shape and the like. Preferably, the center particle size is, for example, in the range of about 0.1 to 10 μm.

In the present invention, the type, particle size, particle shape, mixing ratio, etc. of the phosphor raw material are not particularly limited. For example, among the phosphor raw materials, the aluminum compound has a spherical shape or a substantially spherical shape. It is preferably aluminum oxide in the form of a plate, hexagonal plate, needle, particle, fine powder, or the like, and more preferably spherical or substantially spherical aluminum oxide. If an aluminum compound having such a shape is used, the specific surface area is small, and the shape of most of the particles is a spherical or substantially spherical aluminate phosphor excellent in deterioration resistance such as oxidation resistance and ion impact resistance. And such a phosphor exhibits high luminance and high performance. Specific examples of the particulate aluminum oxide include:
For example, Sumikoundumu (trade name) manufactured by Sumitomo Chemical Co., Ltd. is mentioned.

As described above, for example, in the case of producing a phosphor having a shape derived from the shape of the aluminum compound raw material, it is preferable to perform firing without using a reaction accelerator at the time of firing. Is not limited to, for example,
The raw materials may contain a reaction accelerator (flux) or the like that increases the reactivity between the raw materials. Examples of the reaction accelerator include aluminum fluoride, magnesium fluoride, barium fluoride, boric acid, and boron oxide. Further, a substance other than the reaction accelerator may be contained. The proportions of these substances are not particularly limited as long as they do not hinder the production method of the present invention.

The means for mixing the phosphor raw material powder is not particularly limited as long as the respective raw materials can be mixed. For example, various mixing means such as an automatic mortar and a ball mill can be employed.

Next, the inside of the airtight container 1 is set to a reducing atmosphere with the shutters 13b and 13c closed. By setting the atmosphere in a reducing atmosphere, for example, it is possible to prevent deterioration and disconnection due to oxidation of the graphite heater 3 and, at the same time, to heat and react the phosphor raw material powder 7 while reducing it, thereby obtaining a high-luminance and high-performance aluminate fluorescent material. Body can be manufactured.

The reducing atmosphere 9 includes, for example, a nitrogen-hydrogen mixed gas atmosphere, a carbon monoxide gas atmosphere, and the like. In the present invention, the type is not particularly limited as long as it is in a reducing state. In addition, for example, in a high-temperature state, particularly in a high-temperature state of 1600 to 2000 ° C., various high-temperature atmospheres such as a vacuum atmosphere, a nitrogen gas atmosphere, an inert gas atmosphere, and a reduced-pressure atmosphere of a nitrogen gas or an inert gas also have a reducing property. Therefore, it is included in the reducing atmosphere.

Among these, a reducing atmosphere containing hydrogen gas is suitable for producing a higher-luminance and higher-performance aluminate phosphor, for example, because it has a strong reducing power.
The carbon monoxide gas atmosphere is suitable for continuous firing for a long period of time, for example, since the deterioration of the graphite heater 3 is further suppressed. Further, in the high temperature state, each atmosphere such as a vacuum atmosphere, a nitrogen gas atmosphere, an inert gas atmosphere, and a reduced pressure atmosphere of a nitrogen gas or an inert gas can be used, for example, without damaging the graphite heater 3 or the graphite heat-resistant fiber. It is suitable for continuous firing of aluminate phosphor for a longer period.

When the reducing atmosphere 9 is a nitrogen-hydrogen mixed gas atmosphere, a carbon monoxide atmosphere, a high-temperature nitrogen gas atmosphere, a high-temperature inert gas atmosphere, or the like, the gas flows through the firing furnace 1. The firing may be performed as described above, or the gas may be stored in the firing furnace 1 and fired. In this case, conditions such as a gas flow rate, a storage amount, and a pressure in the firing furnace 1 are not particularly limited, but a specific gas flow rate is, for example, nitrogen 10 to 10 at normal pressure.
The range is 00 cm ³ / min, hydrogen is 0.1 to 100 cm ³ / min, and carbon monoxide is 10 to 1000 cm ³ / min.

The heat-resistant container 6 is filled with the phosphor raw material powder 7 prepared as described above, the lid 10 is placed on the heat-resistant tray 5, the shutter 13a of the front chamber 11 is opened, and the inner rail is opened. After sending it up, shutter 13a
Close. Then, the front chamber 11 through the valve 14a.
Is evacuated or subjected to gas replacement as described above, and then the same reducing atmosphere as in the hermetic container 1 is set.
If the front chamber 11 is made to have the same conditions as the inside of the airtight container 1 as described above, the reducing atmosphere of the airtight container 1 can be maintained even if the shutter 13b located between the front chamber 11 and the airtight container 1 is opened, as described later. Can hold enough.

Next, the graphite heater 3 is energized to heat the airtight container 1. The temperature in the airtight container 1 is
Although it can be appropriately determined depending on the type of the desired phosphor and the like, in particular, the present invention is useful for firing at a high temperature, for example,
The temperature of the heating zone is preferably in the range of 1600 to 2000 ° C, more preferably 1650 to 1850 ° C.

Then, the shutter 13b at the carry-in entrance is opened, and the heat-resistant tray 5 arranged on the rail 8 of the front chamber 11 is pushed forward to be carried into the airtight container 1. Note that the heat-resistant tray 5 may be moved as described above. Then, the phosphor raw material powder 7 on the heat-resistant tray 5 carried into the airtight container 1 undergoes a chemical reaction to produce a phosphor. The firing time is
For example, it is appropriately determined depending on the type of the desired phosphor, the firing temperature, and the like.

On the other hand, the rear room 12 is similar to the front room 11,
The same reducing atmosphere as in the airtight container 1 is set via the valve 14b. Thereby, as described later, even if the shutter 13c located between the rear chamber 12 and the airtight container 1 is opened, the reducing atmosphere in the airtight container 1 can be maintained.

The tray 5 on which the heat-resistant container 6 filled with the phosphor raw material powder 7 is placed is newly disposed in the front chamber 11, and the shutters 13b and 13c at the entrance and exit are opened. Is pushed into the airtight container, and at the same time, the heat-resistant tray 5 fired by this is pushed out from the carry-out port to the rear chamber 12. Then, again, the shutters 13b, 1
After closing 3c, the atmosphere is introduced into the rear chamber 12 to return to the atmosphere, the shutter 13d is opened, the heat-resistant tray 5 is taken out, and the phosphor in the heat-resistant container 6 is collected. In addition, tray 5
After taking out, it is preferable to close the shutter 13d in the rear chamber and perform vacuuming or gas replacement as described above.

By repeatedly performing the above steps, a phosphor can be manufactured continuously without being affected by a thermal shock or the like.

(Embodiment 2) FIGS. 4 to 6 show an example of a manufacturing apparatus used in the manufacturing method of the present invention, in which a graphite core tube is arranged in an airtight container. 4 is a cross-sectional view of the manufacturing apparatus as viewed from the front, FIG. 5 is a cross-sectional view of the manufacturing apparatus as viewed from above, and FIG. 6 is a cross-sectional view of the manufacturing apparatus as viewed from the side. 4 to 6
, The same parts as those in FIGS. 1 to 3 are denoted by the same reference numerals.

In the manufacturing apparatus, a graphite furnace core tube 15 is disposed substantially at the center of the inside of the airtight container 1, and a rail 8 for conveying the tray 6 into the graphite furnace core tube 15.
Is arranged. In addition, the graphite heater 3
It is arranged outside the graphite furnace tube 15. And the airtight container 1, the front room 11, and the rear room 12
6, except that it has the same configuration as the manufacturing apparatus shown in the first embodiment. The gantry 16 is not shown in FIG.

As described above, the graphite furnace core tube 15 differs from the conventional alumina furnace core tube in that, for example, it has excellent thermal shock resistance and is hardly affected by a temperature change or the like. In addition, the graphite core tube is easy to process, for example, and can be easily manufactured even if it is an integral large core tube. Therefore, if this graphite core tube is placed in the hermetic container and baked in a reducing atmosphere inside the tube, for example, even if an oxidizing gas or the like is generated during firing, the oxidizing gas will Since it comes into contact only with the inside of the pipe, it is possible to prevent the heat-resistant fiber heat insulating material on the inner wall of the hermetic container from being deteriorated by contact with the oxidizing gas.

The size of the graphite core tube can be determined as appropriate depending on, for example, the size of the airtight container.
For example, a height range of 10 to 80 cm, a width of 10 to 80 cm
Range, depth length range 1-50m, thickness 1-10
cm. The shape of the graphite core tube is not particularly limited, and examples thereof include a hollow prismatic shape and a hollow cylindrical shape.

The gantry 16 supports the manufacturing apparatus in the present embodiment. For example, the size and the material are not particularly limited. For example, the height is in a range of 10 to 150 cm and the width is in a range of 10 to 200 cm. , Depth 1-50
cm. Examples of the material include metals such as iron and stainless steel.

When the phosphor is manufactured using the manufacturing apparatus of this embodiment, the raw material powder of the phosphor is fired while the inside of the graphite furnace tube 15 is set to the above-described reducing atmosphere and firing temperature, while the airtightness is maintained. Inside the container, for example, vacuum,
It can be manufactured in the same manner as in the first embodiment except that the atmosphere is nitrogen, an inert gas or the like. The condition inside the airtight container is more preferably a vacuum of 1 Pa to 10 ^-8 Pa.

[0076]

Next, examples of the present invention will be described together with comparative examples.

Example 1 The manufacturing apparatus shown in FIG. 1 was manufactured, and an aluminate phosphor was manufactured by continuous firing. Combined 2cm thick stainless steel plate, length 1
A hollow stainless steel rectangular cylinder having a width of 0 m, a width of 60 cm and a height of 50 cm is used as the hermetic container body 2, and front and rear chambers 11 and 12 each having a stainless steel shutter which can be opened and closed at both ends thereof. Were provided, whereby the airtight container 1 was produced. On the inner wall of the airtight container 1,
A heat insulating material 4 made of a heat-resistant fiber having a thickness of 7.5 cm, which was formed by pressing graphite fibers under a pressure of about 160 kg / m ³ , was provided. And as the heater, the outer diameter (φ) 1.2c
A round rod-shaped graphite heater 3 having a length of 30 cm and a length of 30 cm was used, and these were arranged at a constant distance (10 cm) from the upper surface and the bottom surface of the airtight container 1 so as to be spaced apart by 6 cm in the depth direction. Then, on the top of the heater on the bottom surface of the airtight container 1, a thickness of 5 cm and a width of 2
A plurality of graphite square plates of 5 cm and 25 cm in length are arranged so as to be connected to each other, and are about 25 cm in width and 9.6 in length.
m of rails 8 were formed. In addition, at both ends of the rail 8,
An edge is provided as shown in FIG. 1 (height 1 cm, width 2 cm),
The tray 5 to be conveyed does not protrude from the rail 8.

As the tray 5, a 3 L graphite container (purity 99%, square container with lid) was used. As the heat resistant container 6, a 1 L high purity alumina heat resistant container (purity 99.8%) was used. As described above, each of the square containers with lids) was prepared.

The closed chamber front chamber 11 and rear chamber 12 arranged adjacent to the carry-in and carry-out ports of the hermetic container 2 are brought into the same reducing atmosphere as in the hermetic container 1 as described above.
The tray 5 is carried into the airtight container 1 and the airtight container 1
It was provided to keep the reducing atmosphere in the airtight container 1 by carrying it out.

[0080] reducing atmosphere of the airtight container 1, the front chamber 11 and rear chamber 12, a nitrogen hydrogen mixed gas atmosphere at normal pressure nitrogen 380 cm ³ / min, was carried out under the conditions of hydrogen 20 cm ³ / min flow rate and flow rate ratio .

In the front chamber 11, a carry-in device (not shown) called a pusher is arranged. This has a piston structure, and the piston in the cylinder is operated by hydraulic pressure, air pressure, or the like, and the tray 5 can be pushed from the front chamber 11 into the airtight container 1 by the piston.

The conveying speed of the tray 5 is 40 cm / hour, the length of the slow tropical zone of the airtight container (firing furnace) 1 from the loading entrance side is 3.2 m, the length of the heating zone is 1.6 m, and the slow cooling zone. Was 3.2 m, and the length of the cooling zone was 1.6 m.

The firing temperature is monitored by a plurality of infrared radiation thermometers installed in the hermetic container 1.
The measured temperature of the internal heating zone is a predetermined temperature (1400 to 20
(Range of 00 ° C.). At the time of firing, tap water is supplied to a water cooling pipe (not shown) provided on the outer periphery of the hermetic container body 2 (hollow stainless steel prism) to cool the outer wall of the hermetic container 1 and adjust the temperature. went.

As described below, a (Ba, Sr) MgAl ₁₀ O ₁₇ : Eu ²⁺ , Mn ²⁺ aluminate phosphor was produced using the above-mentioned production apparatus.

First, a phosphor raw material powder 7 was prepared. This is made of barium carbonate powder (purity 99.95%, particle size 2-3)
μm), strontium carbonate powder (purity 99.9%, particle size 2-3 μm), basic magnesium carbonate powder (purity 9
9.9%, particle size 2-3 μm), aluminum oxide powder (purity 99.999%), europium oxide powder (purity 99.9%, particle size 2-3 μm), manganese carbonate powder (purity 99.9%, Each powder having a particle size of 2-3 μm) was used in a weight ratio of 7.89: 7.38: 9.50: 51.0: 1.7.
6: 0.115, and these were mixed by a rotary mill to prepare a predetermined amount of mixed powder, which was used as the phosphor raw material powder 7 for the mass production trial. As the aluminum oxide powder, pseudo-spherical α-Al ₂ having a central particle diameter of 3 μm is used.
O ₃ (Product name Advanced Alumina “Sumicorundum”
AA-3; manufactured by Sumitomo Chemical Co., Ltd.)
Aluminum fluoride (AlF ₃ ), magnesium fluoride (M
No reaction accelerator such as gF ₂ ) was used.

Next, 1 kg of the phosphor raw material powder was placed in a heat-resistant container 6 made of high-purity alumina having a content of 1 L (purity: 99.8%).
As described above, the container was filled with a lid 10 made of high-purity alumina so that a small amount of carbon soot generated during firing was not mixed. The high-purity alumina heat-resistant container 6 thus filled with the phosphor raw material powder 7 is
It was placed in a 3 L graphite container (99% purity, square container with lid) prepared as tray 5, and the tray was covered with a special lid made of graphite.

In this way, a number of trays 5 in which the heat-resistant containers 6 are arranged are prepared, and (Ba, Sr) MgAl ₁₀ O ₁₇ :
It was used for producing Eu ²⁺ , Mn ²⁺ aluminate phosphor.

Next, one of the plurality of trays 5 is first placed on the rail 8 of the front chamber 11, and the front chamber 11 is evacuated. The gas was filled, and the atmosphere was set to a nitrogen-hydrogen atmosphere at normal pressure. Thereafter, the shutter 13b provided between the front chamber 11 and the airtight container 1 was opened, and the tray 5 was carried into the airtight container (firing furnace) 1 using the carry-in device.

Next, a new tray is placed adjacent to the loaded tray, and the new tray is pushed by the loading device, whereby the previous tray is pushed further inward, and the new tray is placed in an airtight container. It was carried into 1. By repeating this operation, as shown in FIG. 2, the plurality of trays 5 are connected in a daisy chain and sequentially pushed into the discharge side of the hermetic container 1, and the tray 5 is moved into the pre-gradient tropical zone in the hermetic container (firing furnace) 1. , A heating zone, a slow cooling zone, and a cooling zone. As a result, the phosphor raw material powder in the heat-resistant container is heated and reacted, and (Ba, Sr) MgAl ₁₀ O ₁₇ : Eu ²⁺ , M
An n ²⁺ aluminate phosphor was synthesized. The firing time for firing one tray was 4 hours. afterwards,
The tray 5 pushed to the end on the carry-out side of the airtight container 1 is
After opening the carry-out port, it was fed into the rear chamber 12 filled with the same reducing atmosphere as in the airtight container 1. And again,
After closing the shutter 13c, the rear chamber 12 was evacuated to the atmosphere, and then the shutter 13d was opened to take out the tray 5 and collect the aluminate phosphor in the heat-resistant container 6.

By repeating this operation, (B
a, Sr) MgAl ₁₀ O ₁₇ : Eu ²⁺ , Mn ²⁺ aluminate phosphor was mass-produced at a production rate of about 40 kg / day (corresponding to about 1.2 tons / month).

The obtained (Ba, Sr) MgAl after firing
_{The 10} O ₁₇ : Eu ²⁺ , Mn ²⁺ aluminate phosphor was a weak sintered body in which sintering of powders was slightly observed. After that, the powder was crushed by a ball mill and then classified by a vibration sieve. Thus, coarse particles of 12 μm or more were removed, followed by washing with water to remove fine particles of 1 μm or less. Thus, an aluminate phosphor having a center particle size of about 6 μm and having a predetermined particle size distribution (1 to 12 μm) suitable as a phosphor for a fluorescent lamp or a plasma display was obtained.

(Example 2, Comparative Example 1) Using the production apparatus of Example 1, high-temperature continuous firing was performed in a reducing atmosphere. This is because the heating temperature of the heating zone in the airtight container (firing furnace) 1 is increased at a rate of 200 to 250 ° C./hour.
It takes 8 hours to reach a predetermined temperature (1600 ° C, 1800 ° C)
(2000 ° C., 2000 ° C.), except that the temperature was raised to 2000 ° C.), thereby producing an aluminate phosphor. FIG.
2 shows the temperature history of the heating zone of the hermetic container (firing furnace) 1 in this embodiment.

As Comparative Example 1, an aluminate phosphor was produced in a reducing atmosphere by a conventional method for producing an aluminate phosphor at a mass production level. The temperature history of the heating zone in this case is shown by a dotted line in FIG. In Comparative Example 1,
A core tube made of alumina bricks instead of an airtight container,
Molybdenum disilicide heaters were used in place of the graphite heaters. Then, except that the heater was disposed in the alumina furnace tube so as to generate heat in the atmosphere, the inside was filled with a nitrogen-hydrogen mixed gas, and the tray on which the phosphor raw material powder was placed was transported. A phosphor was manufactured under the same conditions as in Example 2.

As shown, according to the second embodiment, the temperature of the heating zone is changed from room temperature to 1600 ° C., 1800 ° C., 2000 ° C.
, And the temperature could be maintained for several hours or more. Example 2
In the above, an airtight container (firing furnace) such as disconnection or remarkable wear of the graphite heater 3, damage to the heat-resistant fiber insulating material 4, damage to the airtight container 1, damage to the heat resistant container 6 and the tray 5, etc.
No wear or damage was observed in the component members. On the other hand, according to Comparative Example 1, at a temperature of 1600 ° C., continuous firing for about several tens of hours or more was possible.
If continuous firing is attempted at a temperature exceeding 600 ° C., 1650
The heater was disconnected at a temperature of about ° C, and continuous firing was impossible.

As described above, according to the method for producing an aluminate phosphor of the present invention, 1600 to 200 in a state of maintaining a reducing atmosphere, which could not be achieved by the conventional production method.
Continuous firing at 0 ° C. became possible, and particularly excellent continuous firing at a temperature higher than 1600 ° C. and 2000 ° C. or lower.

Example 3 and Comparative Example 2 Using the manufacturing apparatus of Example 1, a long-time continuous high-temperature firing in a reducing atmosphere was performed. This means that the heating temperature of the heating zone in the hermetic container (firing furnace) 1 is increased from room temperature to a predetermined temperature (1600) over a period of 8 hours at a heating rate of 200 to 250 ° C / hour.
C., 1800.degree. C., 2000.degree. C.) and carried out in the same manner as in Example 2 except that continuous firing was performed for 720 hours. FIG. 8 shows an airtight container (firing furnace) 1 in Example 2.
Are shown by solid lines.

In Comparative Example 2, continuous firing was performed for 72 hours.
The procedure was performed in the same manner as in Comparative Example 1 except that the procedure was performed for 0 hour. In addition, from the result of Comparative Example 1, it was found that the sintering at 1800 ° C. and 2000 ° C. was impossible with the conventional manufacturing method.
It was set to 0 ° C. The temperature history of the heating zone in this comparative example is shown by a dotted line in FIG.

As shown, according to the third embodiment, 160
After the temperature was raised to each of the firing temperatures of 0 ° C., 1800 ° C., and 2000 ° C., the firing temperature was raised to 50
It was possible to keep holding for more than 0 hours (about 21 days). In addition, as in the case of Example 2, even when the firing was performed at the high temperature for a long time, the components of the hermetic container (firing furnace) were not consumed or damaged at all. On the other hand, according to Comparative Example 2, even at a firing temperature of 1600 ° C., it is difficult to perform continuous firing for 500 hours or more as in Example 3, and it takes about 200 hours (about 8 days). The molybdenum disilicide heater was disconnected, preventing continuous firing.

As described above, according to the method for producing an aluminate phosphor of the present invention, high-temperature continuous treatment in a reducing atmosphere at 1600 to 2000 ° C. for 500 hours or more, which was impossible with the conventional production method, Sintering can be performed without difficulty.

Example 4 and Comparative Example 3 Using the manufacturing apparatus of Example 1, the firing furnace was repeatedly started and stopped. This means that the temperature of the heating zone is raised by a heating rate of 2 over 8 hours.
Under the condition of 00 to 250 ° C./hour, the temperature is raised from room temperature to a predetermined firing temperature (1600 ° C., 1800 ° C., 2000 ° C.), and after maintaining the firing temperature for 4 hours, 200 to 250 ° C.
The operation of cooling the temperature to about 200 ° C. under the condition of ° C./hour was repeated several times. FIG. 9 shows the temperature history of the heating zone of the hermetic container (firing furnace) 1 in the fourth embodiment with a solid line.

Comparative Example 3 was performed in the same manner as in Comparative Example 1 except that the same temperature change as in Example 4 was performed. In addition, from the result of Comparative Example 1, it was found that the sintering at 1800 ° C. and 2000 ° C. was impossible with the conventional manufacturing method.
It was set to 0 ° C. The temperature history of the heating zone in this comparative example is shown by a dotted line in FIG.

As shown, according to the fourth embodiment, 160
It was found that the heating and cooling up to the respective firing temperatures of 0 ° C., 1800 ° C., and 2000 ° C. can be repeated. Further, similarly to the above-described Example 2, even if the firing is performed at a high temperature for a long time,
No wear or damage was found in any of the components of the firing furnace. On the other hand, according to Comparative Example 3, it is impossible to repeat the production-pause of the aluminate phosphor, that is, the start-stop of the firing furnace 1 even at a relatively low firing temperature of 1600 ° C. there were. Specifically, once 1
When the temperature was raised to 600 ° C., the furnace core tube was damaged at around 1400 ° C. during the temperature drop, and the reducing atmosphere could not be maintained, and the firing furnace could not be repeatedly started and stopped.

As described above, according to the method for producing an aluminate phosphor of the present invention, the production and suspension of the aluminate phosphor in a state where the reducing atmosphere is maintained, which cannot be achieved by the conventional production method, ie, Thus, the start-stop of the firing furnace 1 can be repeated without any problem.

Example 5 and Comparative Example 4 Using the manufacturing apparatus of Example 1, the temperature of the heating zone in the firing furnace was set to 140
The temperature was repeatedly raised and lowered between 0 ° C and 2000 ° C. This is because the temperature of the heating zone is raised from room temperature to a sintering temperature of 2000 ° C. under the condition of a heating rate of 250 ° C./hour, and after maintaining the sintering temperature for 4 hours, 140 ° C. under the condition of 250 ° C./hour.
The operation of lowering the temperature to about 0 ° C., maintaining the temperature for 4 hours, and raising the temperature to 2000 ° C. again was repeated several times. FIG. 10 shows the temperature history of the heating zone of the hermetic container (firing furnace) 1 in the fifth embodiment with a solid line.

In Comparative Example 4, the heating zone was heated from room temperature to a firing temperature of 1600 at a heating rate of 250 ° C./hour.
° C, and after maintaining the firing temperature for 4 hours, 2
The operation was performed in the same manner as in Comparative Example 1 except that the operation of lowering the temperature to about 1400 ° C. under the condition of 50 ° C./hour, maintaining the temperature for 4 hours, and raising the temperature again to 1600 ° C. was repeated several times. The temperature history of the heating zone in this comparative example is shown by a dotted line in FIG.

As shown, according to the fifth embodiment, 200
Elevation between 0 ° C. and 1400 ° C. could be repeated. Further, as in the case of Example 2, even if the firing was performed at a high temperature for a long time, the components of the firing furnace were not consumed or damaged at all. On the other hand, in Comparative Example 4, since the core tube was damaged during the first reduction from 1600 ° C. to 1400 ° C., the reducing atmosphere could not be maintained, and the temperature range between the relatively low temperature range 1600 ° C. and 1400 ° C. It can be seen that even in this case, it was impossible to raise and lower the firing temperature.

As described above, according to the method for producing an aluminate phosphor of the present invention, 1400 to 20
The firing temperature can be raised and lowered between 00 ° C. without any problem.

(Example 6) (B) was carried out in the same manner as in Example 2 except that the production apparatus of Example 1 was used for a long period of continuous firing at a high temperature of 1700 ° C in a reducing atmosphere for about 2 months.
a, Sr) MgAl ₁₀ O ₁₇ : Eu ²⁺ , Mn ²⁺ Aluminate phosphor was mass-produced. By this continuous firing, the high-purity alumina heat-resistant container filled with 1 kg of the phosphor raw material powder is carried into the airtight container (firing furnace) 1 2500 times, resulting in a production rate of about 40 kg / day and 2.4 tons. Of aluminate phosphor was produced.

The emission spectrum and chromaticity of the phosphor obtained by the continuous firing over a long period of time were measured under irradiation of ultraviolet rays at 253.7 nm. The measurement of the chromaticity was calculated from the data of the coloring spectrum at every 5 nm. The result of the emission spectrum is shown by a solid line in the graph of FIG. 11, and the results of relative luminance and chromaticity based on CIE chromaticity coordinates are shown in Table 1 below. The “arbitrary unit” in FIG. 11 indicates a relative value (%) when the maximum light emission intensity is 100%.

As a reference example, a conventional aluminate was used.
Depending on the method of manufacturing the phosphor, the firing temperature is 1600 ° C.
(Ba, Sr) MgAl manufactured in one shot under the condition of 4 hours between
_TenO ₁₇: Eu²⁺, Mn²⁺About Aluminate Phosphor
Each measurement was performed in the same manner as described above. This emission spec
The result of the torque is shown by a dotted line in FIG.
Table 1 below shows the results of chromaticity based on E chromaticity coordinates.
You.

[0111]

As shown in the figure, the phosphor obtained by continuous firing at a high temperature in Example 6 showed almost the same emission spectrum as the phosphor produced by one shot of the reference example. A more detailed examination reveals the following.

In the same figure, the peak around the wavelength of 450 nm is shown.
Ku is Eu²⁺Shows ion emission, wavelength around 510nm
Peak is Mn²⁺Each shows the emission of ions
You. Compared with the phosphor of the reference example, the phosphor of the sixth embodiment
But, somewhat, Eu²⁺The emission intensity of the long wavelength component of the ion,
Mn²⁺The emission intensity of ions was weakened. This is 17
By firing at a high firing temperature of 00 ° C, the phosphor
The reaction between the powders is sufficiently performed, and the
(Ba, Sr) Al with light peak_TwoO_Four: Eu²⁺Phosphor
And the contamination of impurity phosphors can be prevented, and
Mn by firing at 1700 ° C. 100 ° C. higher than the reference example
Element evaporates and Mn in the manufactured phosphor²⁺During ion emission
This is probably due to a decrease in cardiac density. Note that this
Like, Eu ²⁺Long wavelength component of ion and Mn²⁺ion
Is a light-emitting component with high visibility,
The emission of the phosphor of Example 6 was caused by the decrease in the emission intensity of both.
As shown in Table 1 above, the y value of chromaticity in light is a reference value.
The chromaticity y value of the example was somewhat smaller.

On the other hand, as shown in Table 1 above, the luminance of the phosphor of Example 6 was approximately 1% higher than the luminance of the phosphor of the reference example. In general, among blue phosphors, a phosphor having a larger y value of chromaticity has a higher luminance even if its luminous efficiency is lower due to the effect of visibility. Considering the influence of the visibility, the luminous efficiency of the phosphor of Example 6 can be considered to be about 4% higher than the luminous efficiency of the phosphor of the reference example. Then, the composition of the phosphor raw material is finely adjusted to have the same emission spectrum as that of the phosphor of the reference example (Ba, Sr) MgAl ₁₀ O ₁₇ : Eu ²⁺ , Mn ²⁺ aluminate phosphor Is manufactured by a method similar to that of the sixth embodiment, the luminance can be considered to be about 4% higher than the luminance of the phosphor of the reference example.

As described above, according to the manufacturing method of the sixth embodiment,
1700 higher than the conventional manufacturing method of the reference example by 1100 ° C.
Even if continuous calcination is performed at a calcination temperature of ℃ for a long period of time, the calcination furnace does not wear out and is damaged, and (Ba, Sr) MgAl ₁₀ O ₁₇ : Eu ²⁺ , Mn ²⁺ aluminate which satisfies a practical level It can be seen that the salt phosphor could be mass-produced.

In the above embodiment, (Ba,
_{Sr) MgAl 10 O 17: Eu} 2+, a case has been described of Mn ²⁺ aluminate phosphor, in the same manner, BaMgAl ₁₀
O ₁₇ : Eu ²⁺ , Sr ₄ Al ₁₄ O ₂₅ : Eu ²⁺ , CeMgA
^{_{l 11 O 19: Tb 3+,}} BaAl 1 2 O 19: Mn 2+, Y 3 Al 5
O ₁₂ : Tb ³⁺ , CaAl ₂ O ₄ : Eu ²⁺ , Nd ³⁺ , SrA
As for aluminate phosphors such as l ₂ O ₄ : Eu ²⁺ , Dy ^3+, etc., high-luminance phosphors satisfying a practical level could be produced at a mass production level.

(Embodiment 7, Comparative Example 5) (Ba, Sr) MgAl ₁₀ O ₁₇ : Eu
²⁺ (Ba _0.5 Sr _0.4 Eu _0.1 MgAl ₁₀ O ₁₇ ), CaA
l ₂ O ₄ : Eu ²⁺ , Nd ³⁺ (Ca _0.96 Eu _0.02 Nd _0.02 A
l ₂ O ₄ ) and Sr ₄ Al ₁₄ O ₂₅ : Eu ²⁺ (Sr _3.8 Eu
_0.2 Al ₁₄ O ₂₅ ) were prepared. In addition, unless otherwise indicated, it carried out by the same baking procedure and baking conditions as said Example 1.

As the raw material powder of the phosphor, barium carbonate,
From strontium carbonate, calcium carbonate, basic magnesium carbonate, aluminum oxide, europium oxide, and neodymium oxide, powders which were appropriately selected and mixed so as to have a predetermined weight ratio shown in Table 2 below were used. Each of the powders used had a purity of 99.9% or more, and the powder used had a particle size of about 2 to 3 μm. In addition, the aluminum oxide powder was used in Example 1.
A pseudo-spherical α-Al ₂ O ₃ (trade name: Advanced Alumina) having a central particle size of 3 μm was used, and no reaction accelerator such as a fluorine compound or a boron compound was used.

[0119]

The temperature of the heating zone of the firing furnace is set to (Ba, Sr)
MgAl ₁₀ O ₁₇ : 1700 ° C., suitable for Eu ²⁺ phosphor
1450 suitable for aAl ₂ O ₄ : Eu ²⁺ , Nd ³⁺ phosphor
° C, 1550 suitable for Sr ₄ Al ₁₄ O ₂₅ : Eu ²⁺ phosphor
° C for 24 hours, 1
Firing was performed for 2 hours and 12 hours to continuously produce the above three kinds of phosphors. FIG. 12 shows the temperature history of the heating zone of the hermetic container (firing furnace) 1 in the seventh embodiment with a solid line.

Comparative Example 5 was performed in the same manner as in Comparative Example 1 except that the same temperature change as in Example 4 was performed. In addition, from the result of the comparative example 1, it was found that it was impossible to perform calcination at a temperature exceeding 1600 ° C. by the conventional manufacturing method. Therefore, in the comparative example 5, (Ba, Sr) MgAl
The firing of the ₁₀ O ₁₇ : Eu ²⁺ phosphor was performed at 1600 ° C. The temperature history of the heating zone in Comparative Example 5 is shown in FIG.
Is indicated by a dotted line.

The three kinds of aluminate phosphors have similar properties of the constituent elements of the phosphor, and have almost no adverse effect on each other even when manufactured using the same firing furnace. The optimum firing temperature of each of these phosphors is 1
700 ° C, 1450 ° C, and 1550 ° C. Each of the aluminate phosphors is a phosphor whose order is small at present, and its cost increases if manufactured separately. In addition, in the conventional aluminate phosphor manufacturing method, in which it is difficult to raise and lower the heating temperature of the firing furnace because the optimum values of the firing temperatures are different from each other, all of the various phosphors are optimized by using the same firing furnace. It could not be produced at the firing temperature.

However, as shown in FIG. 12, according to Example 7, the firing temperature was 1700 ° C., 1450 ° C., 1550 ° C.
° C, and the firing reaction was completed without the consumption and breakage of the firing furnace, which resulted in the production of three types of phosphors. On the other hand, in Comparative Example 5, the firing temperature was set to 16
The temperature was lowered from 00 ° C to 1450 ° C, and the second kind of CaAl
At the time when the production of the ₂ O ₄ : Eu ²⁺ , Nd ³⁺ phosphor was started, the furnace tube was damaged, and further continuous firing was not possible. Therefore, the first kind of (Ba, Sr) MgAl ₁₀ O ₁₇ : E
Only a u ²⁺ phosphor could be produced, and CaAl ₂ O ₄ : E
u ²⁺ , Nd ³⁺ phosphor and Sr ₄ Al ₁₄ O ₂₅ : Eu ²⁺ phosphor could not be produced.

As described above, according to the method for producing a phosphor of the present invention, the temperature can be easily changed, so that the conventional production method cannot. It can be seen that multiple types of aluminate phosphors having different optimum firing temperatures can be manufactured at the respective optimum firing temperatures using the same firing furnace. In addition, although the Example regarding the manufacturing apparatus of this invention shown in Embodiment 2 provided with the graphite core tube was omitted, the same results as in Examples 1 to 7 were obtained.

[0125]

As described above, according to the method for producing a phosphor of the present invention, for example, members such as a heater, a heat-resistant material, and a heat-resistant container are not worn out or damaged, and are subjected to high-temperature conditions, particularly, 1600 to 1600. The phosphor can be stably fired at a high temperature of 2000 ° C. in a reducing atmosphere for a long period of time. Therefore, it is possible to mass-produce a high-luminance and high-performance phosphor, particularly an aluminate phosphor. In addition, even if the firing temperature is raised and lowered and the production is repeatedly started and stopped, various members are not affected in the same manner. For example, in accordance with the order quantity of the phosphor, the production efficiency is improved, and the aluminate phosphor or the like is used. Can be manufactured.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing an example of a phosphor manufacturing apparatus of the present invention.

FIG. 2 is an upward sectional view of the phosphor manufacturing apparatus.

FIG. 3 is a side sectional view of the phosphor manufacturing apparatus.

FIG. 4 is a front sectional view showing another example of the phosphor manufacturing apparatus of the present invention.

FIG. 5 is an upward sectional view of the phosphor manufacturing apparatus.

FIG. 6 is a side sectional view of the phosphor manufacturing apparatus.

FIG. 7 is a graph showing a temperature history of a heating zone of a firing furnace in an example of the manufacturing method of the present invention.

FIG. 8 shows another embodiment of the production method of the present invention.
4 is a graph showing a temperature history of a heating zone of a firing furnace.

FIG. 9 is a graph showing a temperature history of a heating zone of a firing furnace in still another example of the production method of the present invention.

FIG. 10 is a graph showing a temperature history of a heating zone of a firing furnace in still another example of the production method of the present invention.

FIG. 11 is a graph showing an emission spectrum of an aluminate phosphor in still another example of the production method of the present invention.

FIG. 12 is a graph showing the temperature history of the heating zone of the firing furnace in still another example of the production method of the present invention.

[Description of Signs] 1 ... airtight container 2 ... airtight container body 3 ... graphite heater 4 ... heat insulating material made of heat resistant fiber 5 ... tray 6 ... heat resistant container 7 ... phosphor raw material powder 8 ... rail 9 ... reducing atmosphere 10 ... lid 11 ... Front room 12 ... Rear room 13a, b, c, d ... Shutter 14a, b ... Valve 15 ... Graphite core tube 16 ... Stand

Claims (21)

[Claims] 1. An inner wall is covered with a heat-resistant fiber insulation,
A method for producing a phosphor, in which a heat-resistant tray on which a phosphor raw material powder is placed is loaded into an airtight container in which a graphite heater is disposed in an internal space, and the phosphor raw material powder is fired in a reducing atmosphere. 2. The method for manufacturing a phosphor according to claim 1, wherein the heat-resistant tray is continuously carried into the airtight container, and the phosphor raw material powder is fired for each of the carried heat-resistant trays. 3. The method for producing a phosphor according to claim 1, wherein the heat-resistant container is filled with the phosphor raw material powder, and the heat-resistant container is placed on the heat-resistant tray and carried into the airtight container. 4. The airtight container according to claim 1, further comprising a graphite furnace tube therein, wherein the phosphor raw material powder is fired in a reducing atmosphere inside the graphite furnace tube. A method for producing the phosphor according to claim 1. 5. The heat-resistant fiber heat insulating material is made of graphite, alumina, magnesia, zirconia, hafnia, titania, aluminum nitride, titanium nitride, vanadium nitride, zirconium nitride, boron nitride, hafnium nitride,
Tantalum nitride, boron carbide, molybdenum carbide, silicon carbide, tungsten carbide, hafnium carbide, niobium carbide, tantalum carbide, titanium carbide, zirconium carbide, aluminum boride, titanium boride, vanadium boride,
Claims comprising a fibrous body made of at least one substance selected from the group consisting of tungsten boride, hafnium boride, zirconium boride, metal hafnium, metal iridium, metal molybdenum, metal niobium, metal tantalum and metal tungsten. Item 5. The method for producing a phosphor according to any one of Items 1 to 4. 6. The airtight container has a rail passing through the inside of the heat-resistant tray along the carrying-in direction of the heat-resistant tray, and a plurality of the heat-resistant trays are arranged on the rail, and are arranged rearward in the carrying-in direction. The method for manufacturing a phosphor according to any one of claims 1 to 5, wherein the heat-resistant tray located in (1) is moved by pushing a heat-resistant tray located in the front, and the heat-resistant tray is carried in. 7. The airtight container has a rail penetrating therethrough along the carrying direction of the heat-resistant tray, the heat-resistant tray is disposed on the rail, and the rail is moved in the carrying direction. The method for manufacturing a phosphor according to any one of claims 1 to 5, wherein the heat-resistant tray is carried in by being moved. 8. The method for producing a phosphor according to claim 1, wherein the airtight container is a metal container. 9. The material of the metal container is stainless steel,
The method for producing a phosphor according to claim 8, wherein the phosphor is at least one metal selected from the group consisting of iron, aluminum, copper, and nickel. 10. The method for producing a phosphor according to claim 1, wherein the firing temperature is in the range of 1600 to 2000 ° C. 11. The method for producing a phosphor according to claim 1, wherein the firing time is in the range of 0.1 to 50 hours per heat-resistant tray. 12. The phosphor raw material powder contains an aluminum compound in a range of 40 to 90% by weight.
The method for producing a phosphor according to any one of the above. 13. The method according to claim 1, wherein the phosphor is an aluminate phosphor. 14. The method for producing a phosphor according to claim 12, wherein the shape of the aluminum compound is the same or substantially the same as the shape of a desired phosphor. 15. The shape of the aluminum compound is at least one selected from the group consisting of a sphere, a substantially sphere, a plate, a hexagon, a needle, a particle, and a particle. The method for producing a phosphor according to any one of the above. 16. A container having a cylindrical container having openings at both ends, a graphite heater and a rail, one of the two openings serving as a carry-in port, the other serving as a carry-out port, and penetrating through the carry-in port and the carry-out port. Rails are disposed inside the container, and openable shutters are provided at the two openings so that the inside of the container is airtight when closed, and the inner wall of the container is covered with a heat-resistant fiber insulation. Phosphor manufacturing equipment. 17. The apparatus for producing a phosphor according to claim 16, wherein a graphite core tube is further disposed inside the container, and the rail is disposed inside the graphite core tube. 18. The heat insulating material made of heat-resistant fiber is made of graphite, alumina, magnesia, zirconia, hafnia, titania, aluminum nitride, titanium nitride, vanadium nitride, zirconium nitride, boron nitride, hafnium nitride,
Tantalum nitride, boron carbide, molybdenum carbide, silicon carbide, tungsten carbide, hafnium carbide, niobium carbide, tantalum carbide, titanium carbide, zirconium carbide, aluminum boride, titanium boride, vanadium boride,
Claims comprising a fibrous body made of at least one substance selected from the group consisting of tungsten boride, hafnium boride, zirconium boride, metal hafnium, metal iridium, metal molybdenum, metal niobium, metal tantalum and metal tungsten. Item 18. An apparatus for producing a phosphor according to Item 16 or 17. 19. The phosphor manufacturing apparatus according to claim 16, wherein a front chamber is disposed adjacent to the carry-in port, and a rear chamber is disposed adjacent to the carry-out port. . 20. An apparatus for producing a phosphor according to any one of claims 16 to 19, which is used in the method for producing a phosphor according to any one of claims 1 to 15. 21. The apparatus for producing a phosphor according to claim 16, wherein the phosphor is an aluminate phosphor.