JP5408582B2 - Method for producing oxide amorphous fine particles - Google Patents

Description

The present invention relates to a method for producing oxide amorphous fine particles which are precursors of an alpha sialon phosphor. The illumination device having a light-emitting device with an alpha SiAlON phosphor used the precursors is a highly efficient white LED lighting apparatus which is a kind of solid-state lighting fixture, which is expected as a next-generation lighting, Utilizing the features of energy saving and long life, it does not contain harmful substances such as mercury, so there is little environmental impact.

As phosphor used such as white light emitting _{diodes, M x Si 12- (m +} n) Al (m + n) O n N 16-m ( although, m, n is a is a parameter that determines the composition) had an alpha SiAlON compounds represented by Thus, the element in which the solid solution element M is a rare earth element, an alkali metal element, an alkaline earth metal element, or the like has attracted attention (for example, see Patent Documents 1 to 3 and Non-Patent Document 1). This type of phosphor is hereinafter referred to as an alpha sialon phosphor.

  As a method for obtaining an alpha sialon phosphor, Patent Document 1 discloses a method in which raw material powder is reacted at a high temperature and high pressure of 1700 ° C. and 20 MPa using a hot press apparatus. In the hot press method, the sample is synthesized in the form of a pellet. Therefore, in order to obtain a powdered phosphor, a step of pulverizing and powdering after sintering is required. Non-Patent Document 1 discloses a method in which a raw material powder is gas-pressure-sintered at a high temperature and high pressure of 1800 ° C. and 10 atm, and a powder having a particle diameter of 0.5 to 1.8 μm is obtained. Has been. Patent Document 2 discloses that a raw material powder granulated before sintering to an appropriate particle size is subjected to gas pressure sintering at a high temperature and high pressure of, for example, 1700 ° C. and 1.0 MPa to form one lump. A method for producing a phosphor powder having an appropriate secondary particle size by applying a slight force to break the powder after sintering into a powder form is disclosed. In the method disclosed here, the particle size when granulated in advance is set to 20 μm or more.

As a method for producing an alpha sialon phosphor having a high purity and an appropriate particle size distribution, a compound containing Al and one or a mixture of two or more selected from SiO ₂ , Si ₂ N ₂ O, and Si ₃ N ₄ And a method of heating a precursor material mixed with a compound containing an additive such as a rare earth element, an alkali metal element, or an alkaline earth metal element in a reducing nitrogen atmosphere has been proposed (see, for example, Patent Document 3). .)
According to Patent Document 3, compounds such as Al and rare earth elements, alkali metal elements, and alkaline earth metal elements are attached to fine particles such as amorphous SiO ₂ , Si ₂ N ₂ O, and Si ₃ N ₄ . Is used as a precursor material.

  By the way, in a white light emitting diode using phosphor (hereinafter, the light emitting diode is abbreviated as LED), the phosphor is powdered and dispersed in a resin in the vicinity of or around a blue or ultraviolet LED. The particle diameter of the phosphor generally used is approximately the same as the wavelength of light in the order of μm or several times larger than the wavelength of the light. There is a problem that the light extraction efficiency is lowered due to Mie scattering or geometrical optical scattering and back scattering. As a result, before the fluorescent light reaches the outside of the LED lamp package due to multiple scattering, it is absorbed by various members, and the loss ratio increases. The same applies when the alpha sialon phosphor is used for a white LED or the like.

As a method of reducing the loss due to such backscattering of light, there is a method of making phosphor particles have a size of several tens of μm or more. Another possible method is to reduce the particle size to a nano size where light scattering is weak. By making the phosphor nano-sized, light scattering is reduced. As a result, the light extraction efficiency of the white LED is improved, and an improvement in light emission efficiency can be expected. Furthermore, it is desirable that the phosphor used has high purity.
JP 2002-363554 A WO2006 / 6562 pamphlet JP 2005-306692 A Rong-Jun Xie et al., “Optical Properties of Eu2 + in α-SiAlON,” J. Phys. Chem. B, Vol. 108, pp.12027-12031 (2004)

However, the above-described conventional technique has the following problems.
As disclosed in Patent Document 1, when a phosphor is synthesized by a hot press method, pulverization is necessary and it is difficult to obtain a fine powder.
As disclosed in Non-Patent Document 1 and Patent Document 2, when a phosphor is synthesized by a gas pressure sintering method, it is difficult to obtain a fine powder.
In the method disclosed in Patent Document 3, it is difficult to obtain an alpha sialon phosphor powder having a uniform composition even when a precursor mixed with each material is heated in a reducing nitrogen atmosphere. That is, when Al, Ca, and Eu elements diffuse from the surface of the SiO ₂ fine particles toward the inside of the particle, the concentration of the additive is inevitably higher on the particle surface. As a result, it is difficult to mass-produce phosphors having a uniform composition and stable characteristics. The Al, Ca, and Eu are merely examples, and similar problems occur with other additives.

The present invention has been made in view of the above circumstances, a uniform composition, and an object thereof is to provide a stable, high-quality and very fine oxides of amorphous particles prepared how having fluorescent properties.

In order to achieve the above object, the present invention provides a method for producing oxide amorphous fine particles, which is a precursor for synthesizing an alpha sialon phosphor by a reduction nitriding method,
A compound serving as SiO ₂ of (SiX) steam by heating is mixed with O ₂ gas, and steam to become Compound _Al 2 _{O 3} (AlX) by heating is mixed with _{O 2} gas, _{O 2} Pre-mixing the gas;
Adding a vapor of a compound (MX) containing one or more elements selected from rare earth elements, alkali metal elements and alkaline earth metal elements immediately before heating;
Next, subjecting the mixed steam to rapid heating at 1000 ° C. or more per second to sufficiently oxidize the mixed steam to generate an oxide;
Next, a method of producing oxide amorphous fine particles is provided, which comprises a step of rapidly cooling at 250 ° C. or more per second to obtain oxide amorphous fine particles.

  In the method for producing oxide amorphous fine particles of the present invention, it is preferable that the reaction chamber for performing heating and oxidation is a quartz glass tube.

  In the method for producing oxide fine particles according to the present invention, it is preferable to have an MX volatilization chamber upstream of the heating unit and an MX volatilization heat source different from the heat source for heating the reaction unit.

In the method for producing oxide amorphous fine particles of the present invention, in order to prevent the MX vapor volatilized in the MX volatilization chamber and the O ₂ gas from reacting in advance, the O ₂ gas from the MX volatilization chamber to just before the heating unit is O _2. It is preferable to use a reaction chamber provided with an MX channel independent of a gas channel or the like.

  In the method for producing amorphous oxide fine particles of the present invention, it is preferable to use a plurality of MX volatilization chambers and MX volatilization heat sources.

In the method for producing oxide fine particles according to the present invention, MX is an aqueous solution or an alcohol solution, misted with a nebulizer, and one or more gases selected from Ar, He, and N ₂ are used as a carrier gas in a reaction chamber It is preferable to carry it to the surface.

  In the method for producing oxide amorphous fine particles of the present invention, the heat source for heating the reaction chamber is preferably an oxyhydrogen burner, and the temperature of the outer surface of the tube is preferably in the range of 1200 to 1350 ° C.

In the method for producing oxide fine particles according to the present invention, SiX is SiCl _4, which is maintained at 20 to 45 ° C., and is selected from the group consisting of O ₂ gas, N ₂ gas, Ar gas, and He gas. It is preferable that the raw material is transported to the reaction chamber based on the vapor pressure according to the heat retention temperature by bubbling with one or two or more gases.

In the method for producing oxide amorphous fine particles of the present invention, SiX is SiCl ₄ , and this is kept at 60 to 80 ° C. to obtain SiCl ₄ gas, which is O ₂ gas, N ₂ gas, Ar gas, He gas. It is preferable that one or two or more gases selected from the above are used as a carrier gas and conveyed to the reaction chamber.

In the method for manufacturing the oxide amorphous particles of the present invention, AlX is AlCl _3, to generate AlCl ₃ by blowing Cl ₂ gas to Al, 1 kind or two kinds selected Ar, He, from _{N 2} The above gas is preferably transported to the reaction chamber as a carrier gas.

In the method for producing oxide amorphous fine particles of the present invention, MX is selected from the group consisting of Ca acetylacetonate, Eu acetylacetonate, bishexafluoroacetylacetone calcium, and trisdipivaloylmethanate europium. Or it is preferable that they are 2 or more types of compounds.

According to the present invention, it is possible to obtain a high-quality and ultrafine precursor of an alpha sialon phosphor having a uniform composition and stable fluorescence characteristics.
According to the present invention, it is possible to synthesize a precursor with less contamination from the chamber during synthesis of the precursor and less excess impurity concentration.
According to the present invention, fine alpha sialon phosphor particles having a particle size of less than 300 nm, which had not been reported so far, were obtained.
According to the present invention, by using a phosphor powder having a fine particle size capable of reducing Mie scattering, the phosphor-dispersed resin layer can be made to have a high transparency and a small shielding effect, and has a high light extraction efficiency. An LED package structure can be obtained.

The present invention is a method for producing oxide amorphous fine particles which are precursors for synthesizing an alpha sialon phosphor by a reduction nitriding method,
A compound serving as SiO ₂ of (SiX) steam by heating is mixed with O ₂ gas, and steam to become Compound _Al 2 _{O 3} (AlX) by heating is mixed with _{O 2} gas, _{O 2} Pre-mixing the gas;
Adding a vapor of a compound (MX) containing one or more elements selected from rare earth elements, alkali metal elements and alkaline earth metal elements immediately before heating;
Next, subjecting the mixed steam to rapid heating at 1000 ° C. or more per second to sufficiently oxidize the mixed steam to generate an oxide;
And a step of rapidly cooling at 250 ° C. or more per second to obtain oxide amorphous fine particles, and a method for producing oxide amorphous fine particles characterized by comprising: Fine particle and precursor of alpha sialon phosphor, alpha sialon phosphor fine particle using this precursor and method for producing the same, light emitting device combining this alpha sialon phosphor and blue LED, and lighting fixture equipped with the light emitting device It is.

  In the production method of the present invention, amorphous particulates are obtained by adding MX, which is an X compound of element M, immediately before heating the mixed vapor, followed by rapid heating and rapid cooling. Here, M is a metal element to be doped with respect to the amorphous fine particles serving as a parent phase. By this production method, fine particles having a uniform composition up to the inside of the particles can be produced.

In the production method of the present invention, MX is added immediately before heating because, among rare earth elements, alkali metal elements, and alkaline earth metal elements, industrially usable vapors such as Ca and Eu compounds. There are those retained temperature for generating the pressure is above 300 ° C., also, these materials are unstable at high temperatures, easily disassembled, oxidation, since the reaction with other compounds proceeds, O ₂ gas or This is because it is difficult to mix with other source gases in advance and transport them to the reaction chamber.

  In the production method of the present invention, rapid heating can simultaneously oxidize the elements present in the reaction part, so that the composition can be uniform throughout the particles. For example, when the heating rate is slow, since the elements that are easily oxidized are sequentially oxidized, an unevenly deposited portion of the initially oxidized element is formed inside the fine particles obtained after the reaction. In the case of fine particles containing Si—Al—O amorphous as a main component, it was found by experiments that fine particles having a uniform composition can be obtained by rapid heating at 1000 ° C. or more per second. In addition, by rapid cooling, amorphous fine particles having a uniform composition can be produced without unevenly depositing the solid phase of some of the compounds contained. In the case of fine particles containing Si—Al—O amorphous as a main component, it has been experimentally found that fine particles having a uniform composition can be obtained by rapid cooling at 250 ° C. or more per second.

FIG. 1 is a block diagram showing a first example of a production apparatus used for carrying out the method for producing oxide amorphous fine particles of the present invention, in which reference numeral 1 denotes a tubular reaction chamber, and 2 denotes an oxyhydrogen. Burner, 3 is a filter (bag filter etc.) for collecting oxide amorphous fine particles, 4 is a SiX vapor generator, 5 is an AlX vapor generator, and 6 is an MX vapor generator. The manufacturing apparatus of this example includes a reaction chamber 1 into which SiX vapor, AlX vapor, and O ₂ gas are introduced from one end side, and an MX vapor supply path is connected to the reaction chamber 1 to heat the reaction chamber 1. The oxyhydrogen burner 2 is disposed and connected to an exhaust device (not shown) through a filter 3 that captures and collects amorphous fine particles generated by the reaction at the other end of the reaction chamber 1. Yes.

  FIG. 2 is a block diagram showing a second example of the manufacturing apparatus. The same components as those in the manufacturing apparatus shown in FIG. The manufacturing apparatus of this example is an MX vapor generating apparatus in which a concave MX volatilization chamber is provided in a part of the reaction chamber 1 and the MX compound 7 is disposed in the MX volatilization chamber. Is characterized in that it can be heated by the heat-retaining equipment 8 from outside the chamber. Examples of the heat insulation equipment 8 include a mantle heater, a resistance wire heater, and a gas burner. The amorphous fine particles 9 generated in the reaction chamber 1 are captured and collected by the filter 3.

  FIG. 3 is a block diagram showing a third example of the manufacturing apparatus. The same components as those in the manufacturing apparatus shown in FIGS. The manufacturing apparatus of this example has substantially the same configuration as the manufacturing apparatus shown in FIG. 2, but a partition 10 for flowing MX vapor generated here in a predetermined direction in the reaction chamber 1 is added to the MX volatilization chamber. It is configured.

  FIG. 4 is a block diagram showing a fourth example of the manufacturing apparatus. The same components as those in the manufacturing apparatus shown in FIGS. The manufacturing apparatus of this example has substantially the same configuration as the manufacturing apparatus shown in FIG. 2, but in this example, concave MX volatilization chambers are provided at a plurality of locations in the reaction chamber 1, and the same or different MX compounds are provided in each of them. 7A and 7B are put in, and it is comprised so that it can heat with the heat insulation equipment 8, respectively.

FIG. 5 is a configuration diagram showing an example of a bubbling device that can be used as the SiX vapor generation device 4, the AlX vapor generation device 5, and the MX vapor generation device 6. This bubbling device includes a bubbling tank 11 that contains a liquid raw material 12 such as SiCl ₄ , a conduit that supplies a carrier gas to the bubbling tank 11, and a carrier that contains saturated vapor of the liquid raw material discharged from the bubbling tank 11. A conduit for supplying gas to the reaction chamber 1 and a temperature controller 13 for keeping warm while covering the bubbling tank 11 are configured.

  FIG. 6 is a block diagram showing a fifth example of the manufacturing apparatus, in which the same components as those in the manufacturing apparatus shown in FIGS. The manufacturing apparatus of this example has substantially the same configuration as the manufacturing apparatus shown in FIG. 1, but an ultrasonic nebulizer 14 that supplies a mist 16 of the MX compound aqueous solution 15 is used as the MX vapor generating apparatus.

FIG. 7 is a block diagram showing a sixth example of the manufacturing apparatus, and the same reference numerals are given to the same components as those of the manufacturing apparatus shown in FIGS. 1 to 4 and 6. The manufacturing apparatus of this example uses the bubbling apparatus shown in FIG. 5 as a steam generator for supplying SiX vapor (SiCl ₄ steam), and has two types of MX steam generators with the same configuration as the manufacturing apparatus of FIG. Using an MX volatilization chamber structure capable of supplying MX compounds (CaCl ₂ , EuCl ₃ ), further supplying Cl ₂ gas and carrier gas (such as He) into the reaction tank 17 containing Al as an AlX vapor supply device. Then, a device is used that supplies AlCl ₃ produced by reaction (chlorination) in the reaction tank 17 to the reaction chamber 1.

FIG. 9 is a block diagram showing a seventh example of the manufacturing apparatus. The same components as those in the manufacturing apparatus shown in FIGS. 1 to 4, 6 and 7 are denoted by the same reference numerals. The manufacturing apparatus of this example enables AlX and MX to be supplied to the reaction chamber 1 with a single nebulizer device. As the aqueous solution 15 atomized by this nebulizer device, for example, an aqueous solution such as AlCl ₃ or CaCl ₂ can be used.

In the production method of the present invention, by using a quartz glass tube as the reaction chamber 1, a precursor of an alpha sialon phosphor with less contamination of impurities can be produced. Quartz glass has excellent heat resistance and is not easily decomposed even by rapid heating. Further, the main component is SiO ₂ , and there is no problem of contamination during the reaction.

In the production method of the present invention, the MX volatilization chamber and the heat source (heat insulation equipment 8) as shown in FIG. 2 are used, and by using a production apparatus in which the MX volatilization chamber is provided in the reaction chamber 1, Condensation can be prevented as much as possible. Among rare earth elements, alkali metal elements, and alkaline earth metal elements, there are those having a heat retention temperature of 300 ° C. or higher for generating industrially usable vapor pressure, such as Ca and Eu compounds, This method is effective because it is difficult to keep all the lines for conveying the raw material at a high temperature. In addition, these materials are unstable at high temperatures, and easily decompose, oxidize, and react with other compounds. Therefore, it is difficult to preliminarily mix with O ₂ gas or other source gas and transport it to the reaction chamber. For the first time, the vapor phase synthesis of the alpha sialon phosphor precursor material became possible by generating and adding MX vapor just before heating. The heat retention equipment 8 used for volatilization can be efficiently reacted by being provided and kept at a volatilization temperature corresponding to each compound MX by being provided separately from the oxyhydrogen burner for oxygen reaction.

  In the configuration in which the MX volatilization chamber and the heat source are attached to the reaction chamber 1, it is more preferable that the partition 10 is provided as shown in FIG. 3 in order to prevent the MX from being volatilized and simultaneously oxidized.

  In addition, when volatilizing a plurality of MXs, a plurality of types of MXs may be mixed and arranged in one volatilization chamber, but a plurality of MX volatilization chambers are provided as shown in FIG. It is desirable to do. The heat source used for volatilization is provided separately from the hydrogen burner for the oxidation reaction, and further provided independently for each compound, so that the volatilization temperature corresponding to each MX compound is set and kept warm, thereby allowing the reaction to occur efficiently. be able to.

  In the production method of the present invention, an MX addition system as shown in FIG. 6 can also be used. MX is converted into an aqueous solution or an alcohol solution, misted with a nebulizer, and the MX mist and an inert gas, for example, one or more gases selected from Ar, He, and N2 are conveyed to the reaction chamber as a carrier gas. As the nebulizer, an ultrasonic type, a Venturi tube type, or the like can be used. The solvent alcohol is not particularly limited.

  In the method for producing the oxide amorphous fine particles of the present invention, rapid heating at 1000 ° C. or more per second, sufficient oxidation, and rapid cooling at 250 ° C. or more per second are performed locally. This cannot be achieved unless the heat source can be heated sufficiently. The oxyhydrogen burner 2 is optimal for this. Further, the oxyhydrogen burner 2 can control the flow rate of oxygen and hydrogen to be introduced to control the heating power and the shape of the flame, so that sufficient heating can be performed locally. When the heating temperature of the reaction chamber 1 is 1200 ° C. or lower, the reaction rate is low, and more raw materials are wasted. Above 1350 ° C., the quartz glass tube used in the reaction chamber 1 is greatly deformed and stable synthesis cannot be performed.

In the method for producing oxide amorphous fine particles of the present invention, SiCl ₄ is preferable as SiX. SiCl ₄ is a liquid at room temperature and has a vapor pressure. As shown in FIG. 5, by bubbling with a carrier gas, SiCl ₄ corresponding to the saturated vapor pressure at that temperature can be transported. Conveyance amount of net SiCl ₄ can be controlled by controlling the heat retaining temperature of the carrier gas flow rate and SiCl ₄ liquid. However, if the heat retention temperature is less than 20 ° C., the vapor pressure is too low, and the synthesis rate of the fine particles is remarkably reduced. At 45 ° C. or higher, the vapor pressure is too high, and the addition amount is not stable and fine particles having a constant composition cannot be synthesized.

SiCl _{4 has} a boiling point of about 60 ° C. and can be transported and added in the gas phase. When the heat retention temperature is 80 ° C. or higher, the heat retention cost is increased, which is not industrially preferable.

In the method for producing oxide amorphous fine particles of the present invention, AlCl ₃ is preferable as AlX. AlCl ₃ sublimates above 185 ° C. and can be transported and added in the gas phase. Because of its high reactivity with oxygen, an inert gas such as Ar, He, or N ₂ can be used as the carrier gas.

In the method for producing oxide fine particles of the present invention, as MX, Ca (C ₅ H ₇ O ₂ ) ₂ (Ca acetylacetonate), Eu (C ₅ H ₇ O ₂ ) ₃ (Eu acetylacetonate) 1 or 2 selected from the group consisting of Ca (C ₅ HF ₆ O ₂ ) ₂ (bishexafluoroacetylacetone calcium), Eu (O ₂ C ₁₁ H ₁₉ ) ₃ (trisdipivaloylmethanate europium) It is preferable to use more than one species. The four materials listed here can obtain higher vapor pressures at lower temperatures than other Eu and Ca compounds. Therefore, it is possible to easily prevent condensation from the MX volatilization chamber to the reaction chamber, and stable addition to the precursor becomes possible.

  The amorphous fine particles obtained by the above-described method for producing oxide amorphous fine particles of the present invention can provide extremely fine particles having a particle size in the range of 50 to 300 nm. If the particle size of the amorphous fine particles is less than 50 nm, the sintering phenomenon is remarkably advanced when heating in a reducing nitriding atmosphere, which is not desirable. On the other hand, when the particle size exceeds 300 nm, even if the phosphor is dispersed in a resin and coated and mounted on an LED, the scattering by the particles and the light shielding caused by the scattering are large, and the light extraction efficiency of the LED lamp package is high. Since it falls, it is not desirable.

  The precursor of the alpha sialon phosphor according to the present invention is characterized in that M is Ca and Eu, and is made of the oxide amorphous fine particles according to the present invention, which is a Si-Al-Ca-Eu-O system. To do. From each of the prior literatures, a system in which Eu as a luminescent element is added to alpha sialon in which Ca is dissolved shows very excellent fluorescence characteristics. Examples of Ca and Eu compounds that can actually be used are disclosed in each of the prior documents.

  The alpha sialon phosphor precursor and the alpha sialon phosphor according to the present invention can provide extremely fine particles having a particle diameter of 50 to 300 nm. Conventionally, a sufficiently fine alpha sialon phosphor has not been obtained by solid phase sintering. Also, in Patent Document 3, which is a technique for synthesizing high purity, fine, and low-impurity alpha sialon phosphor powder, amorphous silicon dioxide powder having an average particle size of 0.3 μm or an average particle size of 0.5 μm is used as a material. It was used, and was not sufficiently fine from the viewpoint of reducing scattered light. For the first time, we have succeeded in synthesizing an alpha sialon phosphor having a particle size of 50 to 300 nm.

Among the alpha sialon phosphors according to the present invention, a calcium solid solution europium activated alpha sialon phosphor is particularly preferable. This is excellent in luminous efficiency and has an appropriate emission chromaticity. Formula _{Ca X (Si, Al) 12} (O, N) 16: Eu y or _{Ca x Si 12- (m + n} ) Al m + n O n N 16-n: represented by Eu _y.

  The method for producing an alpha sialon phosphor of the present invention is characterized in that the above-described amorphous sialon phosphor fine particles are obtained by heating in a reducing nitriding atmosphere using the amorphous fine particles as a precursor. In this production method, alpha sialon phosphor fine particles emitting bright yellow light are obtained by firing in a reducing nitriding atmosphere at 1400 ° C. to 1900 ° C. When the firing temperature is 1400 ° C. or lower, the reaction hardly occurs, and when the firing temperature is 1900 ° C. or higher, it is difficult to obtain a phosphor having sufficient fluorescence characteristics. The reducing nitriding atmosphere is desirably ammonia. In order to maintain the atmosphere, it is desirable to flow the atmosphere gas at a gas flow rate at which the atmosphere is changed within 30 seconds.

  The light-emitting device of the present invention combines the above-described alpha sialon phosphor fine particles according to the present invention with a blue LED, and thereby, the light extraction efficiency is higher than when a conventional phosphor powder having a particle size that easily causes scattering is used. A light emitting device excellent in the above can be obtained. A combination of the alpha sialon phosphor fine particles and the blue LED can provide a light emitting device that emits white light ranging from a neutral white color to a light bulb color.

  The light emitting device according to the present invention is effective as a light source of a lighting fixture. By using the white light-emitting device of the present invention instead of the conventional white light-emitting device using a phosphor powder having a particle size that is likely to cause scattering, it is possible to obtain a lighting fixture having excellent light extraction efficiency.

As a synthesis system, a precursor (amorphous fine particles) of a Ca solid solution alpha sialon phosphor to which Eu was added as a luminescent element was synthesized according to the present invention using the production apparatus shown in FIG.
SiCl ₄ was used as SiX. O ₂ was supplied as a carrier gas by a bubbling method. The temperature of the bubbling tank was 23 ° C., and the carrier gas flow rate was 250 sccm.
AlCl ₃ was used as the AIX. Cl ₂ gas is blown onto the Al ingot to generate AlCl ₃ . The temperature of the AlCl ₃ reactor was 220 ° C. The flow rate of the gas flowing into the reaction vessel was 150 sccm for Cl ₂ and 390 sccm for He. He gas is added to control the reaction rate of Cl ₂ and Al. When transporting the generated AlCl ₃ vapor to the reaction chamber, the entire piping was kept at 200 ° C. and transported so that the AlCl ₃ vapor was not condensed (solidified) in the piping.
SiCl ₄ vapor and AlCl ₃ vapor generated by these methods were mixed with 1650 sccm of O ₂ gas in a pipe and introduced into a reaction chamber.

A quartz glass tube having a diameter of 40 mm and a thickness of 3 mm was used as the reaction chamber. A part of the quartz glass tube was processed to provide two volatilization chambers, and each was heated and kept warm by an independent oxyhydrogen burner. CaCl ₂ and EuCl ₃ were used as MX. The temperature of CaCl ₂ was 700 ° C., and the temperature of EuCl ₃ was 1300 ° C. A structure in which Ar gas of 50 sccm flows as a carrier gas in each volatilization chamber, passes through an independent flow path provided from the volatilization chamber to immediately before the reaction unit, and merges SiCl ₄ vapor and O ₂ gas in the reaction unit It has become.

  When the point where the source gases merged was heated to 1340 ° C. with an oxyhydrogen burner, an oxidation reaction occurred and oxide fine particles were obtained. The synthesized fine particles were transported on a carrier gas stream and collected by a downstream filter.

  When the obtained fine particles were evaluated by a powder X-ray diffraction method, a peak chart resulting from the crystal structure was not obtained, and it was confirmed that the particles were amorphous particles.

  The SEM observation photograph and EDS map analysis result of the obtained fine particles are shown in FIG. The diameter of the particles was about 200 nm, and Si, Al, Ca, and Eu could be uniformly distributed in the fine particles.

In the same synthesis system as in Example 1, instead of using the bubbling method as a method of transporting SiCl ₄ , this is kept at 60 to 80 ° C. to obtain SiCl ₄ gas, O ₂ gas is used as carrier gas, and carrier gas flow rate Was transported as 250 sccm. As a result, the same result as in Example 1 was obtained.

Alpha sialon in the same synthetic system as in Example 1 using Ca (C ₅ H ₇ O ₂ ) ₂ (Ca acetylacetonate) and Eu (C ₅ H ₇ O ₂ ) ₃ (Eu acetylacetonate) as MX A phosphor precursor was synthesized. These materials were kept warm with an oxyhydrogen burner. Ca acetylacetonate was kept at 180 ° C. and Eu acetylacetonate was kept at 160 ° C.
As a result, similar to Example 1, amorphous fine particles of about 200 nm were synthesized, and Si, Al, Ca, and Eu could be uniformly distributed in the fine particles.

In the same synthetic system as in Example 1, as MX, Ca (C ₅ HF ₆ O ₂ ) ₂ (bishexafluoroacetylacetone calcium) and Eu (O ₂ C ₁₁ H ₁₉ ) ₃ (Trisdipeparoylmethanate europium) Was used to synthesize an alpha sialon phosphor precursor. These materials were kept warm with an oxyhydrogen burner, with bishexafluoroacetylacetone calcium at 250 ° C. and trisdipivaloylmethanate europium at 270 ° C., respectively.
As a result, similar to Example 1, amorphous fine particles of about 200 nm were synthesized, and Si, Al, Ca, and Eu could be uniformly distributed in the fine particles.

Using the synthesis system shown in FIG. 9, a precursor (amorphous fine particle) of Ca solid solution alpha sialon phosphor was synthesized. This synthesis system is different from Example 1 in the method of adding AlX and MX.
As a method for adding AlX and MX, an ultrasonic nebulizer was used. AlCl ₃ was used as AlX, and CaCl ₃ was used as MX. These were used as aqueous solutions. The concentration of the solution was weighed so that Al was 0.5 mol and Ca was 0.5 mol per liter of the solution to prepare an aqueous solution. The atomized aqueous solution was carried on a carrier gas and transferred to the reaction chamber. Ar gas was used as the carrier gas. When the point where the source gases merged was heated to 1340 ° C. with an oxyhydrogen burner, an oxidation reaction occurred and oxide fine particles were obtained. The synthesized fine particles were transported on a carrier gas stream and collected by a downstream filter.
The obtained fine particles were subjected to EDS analysis. The EDS spectrum is shown in FIG. Al and Ca peaks were observed, and it was confirmed that the additive elements were uniformly added.

The Si-Al-Ca-Eu-O amorphous fine particles having a particle size of about 200 nm obtained in Example 1 were used as precursors and heated in a reducing nitridation atmosphere to obtain calcium solute europium activated alpha sialon phosphor fine particles. Synthesized. 0.12 g of this precursor was placed in an alumina boat, placed in an alumina core tube having an inner diameter of 24 mm, and set in a tubular furnace having a heating element outside the core tube. Ammonium gas was introduced from one end of the furnace core tube at a flow rate of 330 ml / min, and the temperature was raised to 700 ° C. at a rate of 500 ° C./hour. From this temperature, the flow rate of ammonia methane gas was set to 1300 ml / min. At the same time, methane gas was introduced into the furnace at a flow rate of 20 ml / min, and the temperature was subsequently raised to 1500 ° C. at a rate of 200 ° C./hr. After maintaining at this temperature for 30 minutes, the supply of methane gas was stopped, and the mixture was cooled to room temperature in an ammonia stream.
FIG. 11 shows a photograph in which the alpha sialon phosphor thus obtained is irradiated with black light on an alumina boat. A phosphor emitting bright yellow light was obtained by excitation of black light.
FIG. 12 shows an emission spectrum measured with a fluorescence spectrophotometer. The excitation during the measurement has a length of 440 nm.

  Using the alpha sialon phosphor fine particles produced in Example 6, a bullet-type white LED lamp was manufactured. First, the structure and manufacturing procedure of the bullet-type white LED lamp 20 of FIG. 13 will be described.

  This bullet-type white LED lamp 20 has two lead wires 22 and 23, one lead wire 22 has a recess at the tip, and a blue LED element 21 having an emission peak wavelength of 450 nm is placed in the recess. Has been. The lower electrode of the blue LED element 21 and the bottom surface of the recess are electrically connected by a conductive paste. The first resin 25 in which the alpha sialon phosphor fine particles 24 are dispersed is transparent and covers the entire blue LED element. The tip portion of the lead wire 22 including the recess, the blue LED element 21, and the first resin 25 in which the phosphor is dispersed are sealed with a transparent second resin 27. The transparent second resin has a substantially cylindrical shape as a whole, and has a lens-shaped curved surface at the tip, which is commonly called a shell type.

  The manufacturing procedure of this lamp is shown. In the first step, the blue LED element 21 having an emission peak wavelength of 450 nm was die-bonded to the element mounting recess on one of the pair of lead wires 22 and 23 using a conductive paste. In the second step, the blue LED element 21 and the other lead wire were wire-bonded with a fine gold wire 26. In the third step, an appropriate amount of the first resin 25 in which the alpha sialon phosphor fine particles 24 are dispersed is applied to the concave portion for element placement so as to cover the blue LED element 21 and pre-depped. Was cured. In the fourth step, the blue LED element 21 and the first resin 25 were surrounded by the second resin 27 and cured. This fourth step was performed by a casting method. Since the lead wires 22 and 23 were formed by forming a pair of lead wires as a pair, the portion connecting the two lead wires 22 and 23 was cut off in the fifth step. The same epoxy resin was used for the first resin 25 and the second resin 27.

  According to the prior art, the first resin in which the phosphor is dispersed is opaque due to scattering of the phosphor powder, and has a package structure with poor light extraction efficiency due to its shielding effect. Since it has become possible to use fine particles that can sufficiently reduce scattering, it has become possible to make the first resin in which the phosphor is dispersed more transparent than before. As a result, a shell-type white LED lamp 20 having a package structure having a higher light extraction efficiency than the conventional one was obtained.

Next, a chip type white LED lamp will be described. FIG. 14 shows an example of use of the chip-type white LED lamp 30 for mounting on a substrate according to the present invention.
The lower support substrate is a white alumina ceramic substrate having a high visible light reflectance, and two electrode patterns 35 and 36 are formed on the surface thereof by metal thin film sputtering. The thickness of the electrode patterns 35 and 36 is about several μm, and there is almost no step between the electrode pattern portion and the alumina surface portion, and it is almost flat. Lead wires 31 and 32 are connected to the two electrode patterns 35 and 36, respectively, and one ends of the wires 31 and 32 are fixed to the electrode patterns 35 and 36 on the upper surface of the substrate using a high melting point solder or the like. One end is an electrode that is exposed to the outside and is soldered when mounted on an electric board. One of the electrode patterns 35 and 36 has one side at the center of the substrate, and a blue LED element 33 having a light emission center wavelength of 450 nm is placed and fixed thereon. The lower electrode of the blue LED element 33 and the lower electrode pattern 35 are electrically connected by a conductive paste, and the upper electrode and another electrode pattern 36 are electrically connected by a gold wire 34. Yes. The alpha sialon phosphor fine particles 38 are dispersed in the resin 37 and mounted in the vicinity of the blue LED element 33. The resin 37 in which the alpha sialon phosphor fine particles 38 are dispersed is transparent and covers the entire blue LED element 33. A wall member having a shape with a hole in the center is fixed on the ceramic substrate. As shown in FIG. 14, the wall surface member has a central portion serving as a hole for holding the resin 37 in which the blue LED element 33 and the alpha sialon phosphor fine particles 38 are dispersed, and the central portion is a slope. ing. This slope is a reflection surface for taking out light forward, and the curved surface shape of the slope is determined in consideration of the light reflection direction. Further, at least the surface constituting the reflecting surface is a surface having a high visible light reflectance having white or metallic luster. In this embodiment, the wall member is made of a white silicone resin. The hole in the central portion of the wall member forms a recess when it is fixed to the ceramic substrate. Here, the resin 37 in which the blue LED element 33 and the alpha sialon phosphor fine particles 38 are dispersed is formed in a convex shape. Is filled. In this embodiment, the resin 37 is a silicone resin. The manufacturing procedure is substantially the same as the manufacturing procedure of Example 7 except for the portion for fixing the lead wires 31 and 32 to the alumina ceramic substrate.

  According to the conventional procedure, the resin in which the phosphor is dispersed is opaque due to the scattering of the phosphor powder, and has a package structure with poor light extraction efficiency due to its shielding effect, but the Mie scattering is sufficient as the phosphor resin. Since it has become possible to use fine particles that can be reduced, it has become possible to make the resin in which the phosphor is dispersed more transparent than before. As a result, a chip type white LED lamp 30 having a package structure superior in light extraction efficiency than the conventional one was obtained.

  As Example 9, a white lighting apparatus using the white LED lamp of Example 7 or Example 8 as an internal component will be described. FIG. 15 is an example of a white lighting fixture using Example 7 or Example 8. The upper part of the white lighting fixture 40 is a box-shaped support portion 42 having a certain strength, and the support portion 42 is fixed to the ceiling or side wall for use. Inside the support portion 42, a drive portion which is an electric circuit for lighting the white LED lamp 41 using a power source supplied from the outside is incorporated. The driving unit is usually composed of a power supply circuit, a white LED lamp driver IC, and peripheral components attached to them. The driver IC may have a function of driving the white LED lamp 41 in a pulsed manner or a dimming function. A large number of white LED lamps 41 of Example 7 or Example 8 are fixedly installed on the support part 42 and are electrically connected to a drive part (not shown). A cover 43 is disposed so as to cover the entire white LED lamp 41. The cover 43 is frosted glass or a transparent resin cover having a certain surface roughness, and has a function as a light scattering member. The cover 43 recognizes that the white light emitted from the white LED lamp 41 does not directly enter the human eye, and that the entire white lighting device 40 emits light brightly. For this reason, when the white LED lamp 41 of Example 7 or Example 8 is directly observed, the reflecting member makes a shade, but this does not cause a problem when using the lighting fixture.

  In the white lighting fixture 40 of the present embodiment, the light extraction efficiency is excellent by using the white LED lamp 41 of the present invention instead of the conventional white LED lamp using a phosphor powder having a particle size that is likely to cause scattering. It became possible to obtain a white luminaire.

It is a block diagram which shows the 1st example of the manufacturing apparatus used in order to implement the manufacturing method of the oxide amorphous fine particle of this invention. It is a block diagram which shows the 2nd example of the manufacturing apparatus used in order to implement the manufacturing method of the oxide amorphous fine particle of this invention. It is a block diagram which shows the 3rd example of the manufacturing apparatus used in order to implement the manufacturing method of the oxide amorphous fine particles of this invention. It is a block diagram which shows the 4th example of the manufacturing apparatus used in order to implement the manufacturing method of the oxide amorphous fine particle of this invention. It is a block diagram which illustrates the bubbling apparatus which can be used by this invention. It is a block diagram which shows the 5th example of the manufacturing apparatus used in order to implement the manufacturing method of the oxide amorphous fine particles of this invention. It is a block diagram which shows the 6th example of the manufacturing apparatus used in order to implement the manufacturing method of the oxide amorphous fine particles of this invention. It is a SEM observation image and EDS map analysis result of the fine particles produced in Example 1. It is a block diagram which shows the 7th example of the manufacturing apparatus used in order to implement the manufacturing method of the oxide amorphous fine particle of this invention. 6 is an EDS spectrum of a precursor of an alpha sialon phosphor produced in Example 5. It is an image which shows the fluorescence generation state of the alpha sialon phosphor manufactured in Example 6. It is the emission spectrum which measured the alpha sialon fluorescent substance manufactured in Example 6 with the fluorescence spectrophotometer. FIG. 10 is a cross-sectional view of a bullet-type white LED lamp produced in Example 7. 10 is a cross-sectional view of a chip-type white LED lamp produced in Example 8. FIG. FIG. 10 is a cross-sectional view of a white lighting fixture produced in Example 9.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Reaction chamber, 2 ... Oxyhydrogen burner, 3 ... Filter, 4 ... SiX vapor generator, 5 ... AlX vapor generator, 6 ... MX vapor generator, 7, 7A, 7B ... MX compound, 8 ... Thermal insulation equipment, DESCRIPTION OF SYMBOLS 9 ... Amorphous fine particle, 10 ... Partition, 11 ... Bubbling tank, 12 ... Liquid raw material, 13 ... Temperature controller for heat retention, 14 ... Ultrasonic nebulizer, 15 ... MX compound aqueous solution, 16 ... Fog, 17 ... Reaction tank , 20 ... Cannonball type white LED lamp, 21 ... Blue LED element, 22, 23 ... Lead wire, 24 ... Alpha sialon phosphor fine particles, 25 ... First resin, 26 ... Gold wire, 27 ... Second resin, 30 ... chip type white LED lamp, 31, 32 ... lead wire, 33 ... blue LED element, 34 ... gold fine wire, 35, 36 ... electrode pattern, 37 ... resin, 38 ... alpha sialon phosphor Particles, 40 ... white luminaire, 41 ... white LED lamp, 42 ... support portion, 43 ... cover.

Claims (11)

A method for producing oxide amorphous fine particles, which is a precursor for synthesizing an alpha sialon phosphor by a reductive nitriding method,
A compound serving as SiO ₂ of (SiX) steam by heating is mixed with O ₂ gas, and steam to become Compound _Al 2 _{O 3} (AlX) by heating is mixed with _{O 2} gas, _{O 2} Pre-mixing the gas;
Adding a vapor of a compound (MX) containing one or more elements selected from rare earth elements, alkali metal elements and alkaline earth metal elements immediately before heating;
Next, subjecting the mixed steam to rapid heating at 1000 ° C. or more per second to sufficiently oxidize the mixed steam to generate an oxide;
And a step of rapidly cooling at 250 ° C. or more per second to obtain oxide amorphous fine particles.  The method for producing oxide amorphous fine particles according to claim 1, wherein the reaction chamber for performing heating and oxidation is a quartz glass tube.  3. The production of amorphous oxide fine particles according to claim 1, further comprising an MX volatilization chamber upstream of the heating unit and an MX volatilization heat source different from the heat source for heating the reaction unit. Method. In order to prevent the MX vapor volatilized in the MX volatilization chamber and the O ₂ gas from reacting in advance, an MX channel independent of the O ₂ gas channel is provided from the MX volatilization chamber to immediately before the heating unit. 4. The method for producing oxide fine particles according to claim 3, wherein a reaction chamber is used.  5. The method for producing oxide amorphous fine particles according to claim 3, wherein a plurality of MX volatilization chambers and MX volatilization heat sources are used. The MX is made into an aqueous solution or an alcohol solution, misted with a nebulizer, and one or more gases selected from Ar, He, and N ₂ are conveyed to the reaction chamber as a carrier gas. The manufacturing method of the oxide amorphous fine particle in any one.  The oxide amorphous fine particles according to any one of claims 1 to 6, wherein the heat source for heating the reaction chamber is an oxyhydrogen burner, and the temperature of the outer surface of the tube is in the range of 1200 to 1350 ° C. Manufacturing method. SiX is SiCl ₄ and is kept at 20 to 45 ° C., and bubbled with one or more gases selected from the group consisting of O ₂ gas, N ₂ gas, Ar gas, and He gas, The method for producing oxide amorphous fine particles according to claim 1, wherein the raw material is conveyed to the reaction chamber based on the vapor pressure according to the above. SiX is SiCl ₄ and is kept at 60 to 80 ° C. to obtain SiCl ₄ gas. One or more gases selected from O ₂ gas, N ₂ gas, Ar gas, and He gas are used as carrier gas. The method for producing amorphous oxide fine particles according to claim 1, wherein the oxide amorphous fine particles are conveyed to a reaction chamber. AlX is AlCl _3, to generate AlCl ₃ by blowing Cl ₂ gas to Al, Ar, He, to carry one or more gases selected from _{N 2} into the reaction chamber as a carrier gas The method for producing oxide fine particles according to any one of claims 1 to 9. MX is one or more compounds selected from the group consisting of Ca acetylacetonate, Eu acetylacetonate, bishexafluoroacetylacetone calcium, and trisdipivaloylmethanate europium. Item 11. A method for producing oxide amorphous fine particles according to Item 1 to 10 .

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