JP2000204366A - Production apparatus of fluorescent substance and vessel for producing fluorescent substance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the subject apparatus having a furnace for heating the raw materials for a fluorescent substance, and a specified vessel for producing the fluorescent substance, capable of efficiently promoting the reduction and nitridation even at the contacting surface with a boat, capable of providing a GaN-based fluorescent substance having good uniformity, and good crystalline shape having clear angles. SOLUTION: Raw materials 3 is loaded on a boat 4 obtained, for example, by mixing a carbonic material such as graphite, amorphous carbon and a carbon-coated alumina, and a BN powder, with a binder, a solvent and the like, inserting the obtained mixture into a mold to compact the mixture, drying the obtained compact, and baking the dried compact, and the raw materials 3 loaded on the boat 4 are inserted into the interior of a tube furnace 1. The raw materials 3 are heated by a heater 2 while flowing ammonia gas in the interior of the tube furnace 1 to provide the fluorescent substance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphor producing apparatus and a phosphor producing container capable of producing a phosphor having good crystallinity.

[0002]

2. Description of the Related Art In recent years, GaN is LE
It is known as a material that emits blue and green light with high luminance in light emitting elements such as D and LD. Conventionally, to manufacture a GaN phosphor, a compound of a doping substance is mixed with a Ga compound as a raw material, and the mixture is placed in a firing furnace and fired at a high temperature while flowing ammonia to nitride Ga and dope. Dope the substance.

[0003] Although attempts have been made in the past to cause the material obtained in this way to emit light with an electron beam, a powdered phosphor has not yet achieved practical brightness.

[0004]

The main reason why luminance cannot be obtained is that, unlike other phosphor materials, it is difficult to perform nitriding. That is, the temperature at which the material is nitrided (7
Since the difference between the temperature (00 ° C. to 1000 ° C.) and the temperature at which decomposition starts (950 ° C. or more) is small, nitridation and decomposition tend to proceed simultaneously in a normal reaction by heating. For this reason, although GaN can be produced, it was not possible to produce GaN that is white and has high crystallinity that can be used as a phosphor.

In order to manufacture a GaN phosphor, as described above, generally, a raw material is fired at a high temperature while flowing a gas containing ammonia or nitrogen in a tube furnace. Therefore, in the synthesis of GaN, a sufficient amount of ammonia must be supplied into the tubular furnace.

[0006] Even if a raw material is put in a conventional box-shaped container (generally called a boat) made of alumina, which is placed in a tubular furnace and fired while flowing ammonia, a uniform nitriding reaction can be obtained. Could not be obtained. This is because alumina boats which have been used conventionally do not have good air permeability, so that a portion of the raw material, particularly the portion in contact with the inner surface of the boat, could not contact the gas. In this part, the nitridation reaction was insufficient, and the obtained phosphor was not uniform, and there was a problem that the luminance when emitting light as the phosphor was partially weakened.

For this reason, even if the GaN phosphors in the same batch are used, only a small portion of the phosphors can provide a certain amount of light emission, and the light emission intensity is too low to be practical. Further, the reproducibility of the production of the GaN phosphor was not desirable, and a GaN phosphor having high emission intensity and stable characteristics could not be obtained.

The present invention provides a phosphor manufacturing container which can be applied to a method of manufacturing a phosphor by heating a phosphor material in a gas atmosphere and which can produce a phosphor having excellent characteristics. The purpose is.

[0009]

According to a first aspect of the present invention, there is provided an apparatus for manufacturing a phosphor, comprising: a furnace for heating a raw material of the phosphor in a gas atmosphere; A phosphor production container which has thermal conductivity for conducting heat of the furnace to the raw material and which accommodates the raw material and is disposed inside the furnace;

[0010] According to a second aspect of the present invention, there is provided a phosphor manufacturing container which contains a raw material of the phosphor, and which is disposed in a gas atmosphere and is heated. And heat conductivity for conducting heat to the raw material.

[0013] A container for producing a phosphor according to claim 3 is formed of a material that does not contain a gas that inhibits a reaction between the raw material and the gas. It is characterized by.

A phosphor manufacturing container according to a fourth aspect of the present invention is the phosphor manufacturing container according to the second aspect, wherein a powder of a substance selected from the group consisting of graphite, amorphous carbon, and carbon-coated alumina is used. It is characterized by being formed by sintering in a porous state.

According to a fifth aspect of the present invention, there is provided a phosphor manufacturing container according to the second aspect, wherein the BN powder is formed by sintering to a porous state. Features.

According to a sixth aspect of the present invention, there is provided a phosphor manufacturing container which contains a raw material of GaN: A (A = Zn, Mg), is disposed in a gas atmosphere containing nitrogen, and is heated. Container having air permeability through which the gas can pass and heat conductivity for conducting heat to the raw material.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to solve the above-mentioned problems, the boat is made porous so that the gas sufficiently contacts the raw material of the GaN phosphor in contact with the inner surface of the boat. We thought it important to be able to pass. However, the boat must be made of a material having sufficiently higher thermal conductivity than conventional alumina so that heating by the furnace is performed efficiently. Also,
It is also necessary that the material has good formability, can form a boat of any shape, is easily available and is inexpensive.

As materials satisfying the above conditions, the present inventors have selected carbon-based materials such as graphite and amorphous carbon, carbon-coated alumina which is a material utilizing carbon, and BN powder. . Powders of these substances were mixed with a binder, a solvent, and the like, molded into a mold, dried, and fired to form a boat. The boat thus obtained was in a porous state and had sufficient thermal conductivity. When the phosphor was manufactured using this, a phosphor in which crystal grains had a large diameter and were uniformly arranged due to good crystal growth was obtained.
In the conventional boat, the light emission was weak because the contact surface of the raw material with the boat did not come into contact with the gas, but in this example, this portion was also efficiently reduced and nitrided, and the uniformity of the sample was improved.
In addition, the repetition reproducibility of the synthesis is improved, and a GaN phosphor having a more stable quality and a higher light emission luminance than that of a conventional boat can be manufactured.

[0017]

EXAMPLES (1) Example 1 1 mol% of Zn to 1 mol% of gallium sulfide
And placed on a porous boat made of amorphous carbon, and mixed in an ammonia atmosphere.
The reaction was performed at 000 ° C. for 3 hours. As a result, the powder Ga
An N: Zn phosphor was obtained.

FIG. 1 is a perspective view showing the above process as an example. A heater 2 as a heating means is provided around the tubular furnace 1.
Is provided. The boat 4 on which the raw material 3 is placed is inserted into the tubular furnace 1. The raw material 3 is heated by the heater 2 while flowing ammonia gas in the tubular furnace 1 as shown by arrows. In addition, in this example, the shape of the boat 4 is obtained by dividing a cylindrical shape having two open ends along the central axis, so that the gas easily comes into contact with the raw material 3. In addition, the curvature of the boat 4 is
And the heat of the heater 2 is easily conducted from the tubular furnace 1. However, this shape is an example, and of course, other structures may be used.

When this phosphor was irradiated with ultraviolet rays from a mercury lamp (365 nm), blue light emission of 440 nm was confirmed.

Further, an ITO having this phosphor formed on a substrate is provided.
It was applied on the electrode by printing and mounted on a fluorescent light emitting tube and a field emission light emitting device. Anode voltage 400V, duty =
When driven at 1/240, blue light emission with good color purity was obtained.

FIG. 2 shows the SE of the GaN phosphor obtained in this example.
FIG. 3 is an M photograph, and FIG. 3 shows a GaN phosphor manufactured using a conventional alumina boat. It was confirmed that the GaN phosphor according to the present example in FIG. 2 was a particle having a better crystal shape with a sharp corner.

(2) Example 2 Example 1 was performed using a porous boat made of graphite.
An experiment similar to that of Example 1 was performed, and a mercury lamp (3
When excited with ultraviolet light (65 nm), blue light emission having a peak at 440 nm was obtained.

(3) Example 3 An experiment was conducted using a porous boat made of carbon-coated alumina. 1 mol of Mg in gallium hydroxide
% / Ga1 mol equivalent of Mg (OH) ₂ was mixed, placed on the boat, and reacted at 1100 ° C. for 3 hours in a nitrogen atmosphere mixed with ammonia. As a result, powder G
An aN: Mg phosphor was obtained.

The emission intensity of this phosphor by ultraviolet excitation was 1.5 times stronger than that of the conventional alumina boat.

According to AES analysis, the phosphor produced using a conventional alumina boat contains 5 mol% of oxygen.
% / Ga1 mol was detected, but the oxygen of the phosphor produced by the boat of this example was below the detection limit. Oxygen is a gas that inhibits the reaction between the raw material and the gas. The results of the AES analysis indicate that the boat of this example is substantially free of harmful gases in such a manufacturing process.

An integrated value was determined for a peak at 2θ = 37 ° in X-ray diffraction. It is considered that the smaller the value, the better the crystallinity. The value of the phosphor produced using the conventional alumina boat was 0.31, but the phosphor produced by the boat of the present example was as small as 0.26, indicating that the crystallinity was better than the conventional one. Was confirmed.

(4) Example 4 The same experiment as in Example 1 was conducted using a porous boat made of BN. In this boat, BN powder is put into an acrylic binder and terpineol, put into a mold, molded, dried and solidified. By firing this, BN
A boat is obtained in which the powder is baked at a low filling degree. According to this example, the mercury lamp (3
When excited with ultraviolet light (65 nm), blue light emission having a peak at 440 nm was obtained.

[0028]

According to the present invention, a phosphor production container containing a phosphor raw material and heated in a gas atmosphere is provided.
It has a gas permeability that allows gas to pass through and a thermal conductivity that efficiently conducts heat to the raw material. As a result, the following effects were obtained in a method for producing a phosphor by a gas phase reaction between a source material and a source gas.

1. In the conventional method, the reaction was insufficient and the light emission was weak because the boat contact surface was difficult to contact with gas, and the light emission was weak. Has improved the uniformity.

2. A phosphor having a good crystal system with sharp corners can be obtained.

3. Due to the above, a phosphor with high emission intensity can be obtained.

According to the phosphor production container of the present invention or the phosphor production apparatus using the same, the following effects can be obtained particularly in the production of a GaN phosphor.

[0033] In the conventional method, the boat contact surface was difficult to contact with hydrogen, so reduction was insufficient and light emission was weak,
By using the phosphor production container of the present invention, reduction and nitridation of the boat contact surface proceeded efficiently, and the uniformity of the sample was improved.

[0034] GaN with good crystal system with sharp corners
A system phosphor is obtained.

[0035] Due to the above, a GaN phosphor having high emission intensity can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a phosphor manufacturing apparatus according to an example of an embodiment of the present invention.

FIG. 2 shows SE of a GaN phosphor obtained in an example of the present invention.
It is an M photograph.

FIG. 3 GaN produced using a conventional alumina boat
It is a SEM photograph of a fluorescent substance.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Tubular furnace, 3 ... Phosphor raw material (Gallium oxide etc. which is a GaN phosphor raw material), 4 ... Fired boat as a container for producing a phosphor.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Fumiaki Kataoka 629 Oshiba Mobara-shi, Chiba Futaba Electronics Co., Ltd. F-term (reference) 4H001 XA31 YA12 YA30

Claims (6)

[Claims] A furnace for heating a raw material of a phosphor in a gas atmosphere; a furnace having a gas permeability, and having a heat conductivity for conducting heat of the furnace to the raw material; A phosphor production apparatus comprising: a phosphor production container containing a raw material and disposed inside the furnace. 2. A phosphor manufacturing container which stores a raw material of a phosphor and is placed in a gas atmosphere and heated, having a gas permeability which allows the gas to pass therethrough and conducting heat to the raw material. For producing a phosphor having thermal conductivity. 3. The phosphor manufacturing container according to claim 2, wherein the container is formed of a material that does not contain a gas that inhibits a reaction between the raw material and the gas. 4. Graphite, amorphous carbon,
3. The phosphor manufacturing container according to claim 2, wherein a powder of a substance selected from the group consisting of carbon-coated alumina is sintered so as to be porous. 5. The phosphor production container according to claim 2, wherein the BN powder is sintered so as to be in a porous state. 6. A phosphor manufacturing container which contains a raw material of GaN: A (A = Zn, Mg) and is placed and heated in a nitrogen-containing gas atmosphere, wherein a gas-permeable material through which the gas can pass. And a heat conductive member for transferring heat to the raw material.