JP2013173868A - METHOD FOR PRODUCING β-SIALON PHOSPHOR - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve luminance of a β-type sialon phosphor.SOLUTION: A method for producing a phosphor having a β-sialon as a base crystal carries out a firing step at least two times, wherein the first firing step prepares a phosphor raw material for first-time firing in which an activating agent element concentration is made lower than a target concentration, and firing the raw material to thereby obtain the first-time fired raw material; and the second firing step fires a raw material for second-time firing in which the activating agent has been added to the obtained first-time fired raw material.

Description

  The present invention relates to a method for producing a phosphor having a β silicon nitride type structure. More specifically, the present invention has a β silicon nitride type structure in which the activator concentration can be adjusted more freely than before and the crystallinity is good. The present invention relates to a method of manufacturing a phosphor.

Recently, as phosphors having a small luminance drop due to temperature rise and excellent durability, attention has been paid to nitride and oxynitride phosphors having a stable crystal structure.
A typical example of the nitride or oxynitride phosphor is sialon, which is a solid solution of silicon nitride. Similar to silicon nitride, sialon has two types of crystal systems, α-type and β-type. A β-sialon activated with a specific rare earth element is known to have useful fluorescence characteristics, and its application to a white LED or the like is being studied.

According to Patent Document 1, it has a specific range of electron spin density, is represented by the general formula Si _6-x Al _x O _x N _8-x (z is 0 to 4.2), and contains β-type containing Eu. A phosphor mainly composed of sialon is excited in a wide wavelength range from ultraviolet light to visible light, and emits green light having a main wavelength within a range of 520 nm to 550 nm with high efficiency. It is disclosed that it is excellent. It is also disclosed that this phosphor can be suitably used for various light emitting elements, particularly white LEDs using ultraviolet LEDs or blue LEDs as a light source, alone or in combination with other phosphors.

  Patent Document 1 also discloses a first step of generating Eu-containing β-type sialon and the obtained Eu-containing β-type sialon in a nitrogen atmosphere, vacuum, or a gas other than nitrogen as a main component. And a second step of reducing the crystal defect density by performing heat treatment at each optimum temperature and time in an inert atmosphere, and further performing acid treatment in some cases. The effect of this second step is to reduce the number of unpaired electrons and improve the luminous efficiency by, for example, decomposing unstable nitride or oxynitride phase with high crystal defect concentration. It is described.

WO2008 / 062781 International Publication Pamphlet

  However, the β-type sialon phosphor described in Patent Document 1 has been required to further improve luminance in practical use.

  Therefore, as a result of intensive studies, the present inventors have determined that the β-type sialon phosphor is shaped like a hexagonal tube when considering the arrangement of atoms in its crystal structure, and the continuous voids inside the tube are formed. Focusing on the special shape that the activator enters inside, and the possibility that the activator element continues to move in the void as long as the void continues inside the crystal, it is different from before An attempt was made to produce a β sialon phosphor by the production method, and the present invention was achieved.

That is, the gist of the present invention resides in the following (1) to (4).
(1) In the phosphor production method using β sialon as a base crystal, at least the firing step is performed twice, and in the first firing step, the concentration is less than the concentration at which the activator element is obtained. A β sialon phosphor characterized in that a phosphor material is prepared, fired, and fired on a phosphor material for second firing in which an activator element is further added to the obtained first fired material. Manufacturing method.
(2) The method for producing a β sialon phosphor according to (1), wherein the β sialon phosphor is represented by the following general formula.

_{Si 6-x Al x O x} N 8-x: Eu y ··· [1]
(Wherein, x and y represent numbers satisfying 0 ≦ x ≦ 4.2 and 0.001 ≦ y ≦ 0.03, respectively) (3) Activator in phosphor material for first firing (1) or (2), wherein the molar fraction of the element with respect to the phosphor is smaller than the sum of the molar fractions of the activator element with respect to the phosphor in the phosphor material for the second and subsequent firings. A method for producing a β sialon phosphor.
(4) The molar fraction of the activator element in the phosphor material for the first firing relative to the phosphor is 10 which is the maximum value of the mole fraction of the activator element in the phosphor material for the second and subsequent firings relative to the phosphor. The method for producing a β sialon phosphor according to claim 1, wherein the β sialon phosphor is at most%. (5) The method for producing a β sialon phosphor according to any one of claims 1 to 4, wherein the activator element is substantially not contained in the phosphor material for the first firing.
(6) A β sialon phosphor produced by the method according to any one of claims 1 to 5.
(7) A β sialon phosphor in which the half width of the peak on the (301) plane of the XRD chart measured by Cu—Kα ray is smaller than 0.105 degrees at 2θ.
(8) A light emitting device using the phosphor according to claim 6 or 7.

  According to the phosphor manufacturing method of the present invention, the luminance of the β-type sialon phosphor can be improved. In addition, when the phosphor manufactured by the manufacturing method of the present invention is used, the luminance of the light emitting device can be increased.

FIG. 1 is an explanatory diagram partially extracting the results of powder X-ray diffraction measurement for explaining the difference in crystallinity between the phosphors obtained in Examples and Comparative Examples of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention.
The technical feature of the present invention is that the β sialon phosphor has an atomic arrangement such as a hexagonal tube, and cares about the factor that inhibits the emission of Eu in the first firing affirmation. Without any adjustment, the particle shape and crystallinity of β sialon, which is the base structure, are adjusted, and the activator is put into the tube in the subsequent process. Many of the nitride phosphors that are actually used have a more complex structure, and the activator element enters the host crystal by substitution with a specific element. In order to send the activator element to the center, it is necessary to replace a very large number of elements in order. For this reason, even if it adds after an activator, an activator element is hard to enter to the center part of fluorescent substance particle, and it is thought that the same effect is hard to be acquired.

Further, in the past, although the fields are greatly different, in the phosphor for PDP that is known to emit light only on the very surface of the phosphor particles, the excitation light ( In this case, it has been known that an activator is added afterwards in order to improve only the concentration of the activator on the surface (which is said to be about 50 nm) to which the vacuum ultraviolet rays reach, but like a phosphor for LED In the case where the particle size is large and the excitation light passes through the entire phosphor particles, it has been considered that it is meaningless to improve the concentration of the activator only on the surface.

[Phosphor production method]
In the production method of the present invention, known methods for producing β sialon phosphors such as raw materials, firing conditions, washing, and classification may be used.
A feature of the present invention is that it has at least two firing steps, and that it does not contain all of the activator element amount of the final target composition in the first firing raw material.
More preferably, the molar fraction of the activator element in the phosphor material for the first firing relative to the phosphor is the sum of the mole fraction of the activator element in the phosphor material for the second and subsequent firings relative to the phosphor. More preferably, the mole fraction of the activator element in the phosphor material for the first firing relative to the phosphor is the mole fraction of the activator element in the phosphor material for the second and subsequent firings relative to the phosphor. It is 10% or less of the maximum value of the rate, and more preferably, the activator element is not substantially contained in the phosphor material for the first firing.

The purpose of the first firing is to adjust the particle shape and crystallinity without worrying about the factors that inhibit the light emission of Eu. In this case, an activator may be added even in the first firing. Even if the amount of the activator element at the first firing is about 95% of the final phosphor and the second is about 5%, the post-addition effect of improving the brightness of the phosphor may be obtained. is there.
However, judging from the shape of the phosphor particles, etc. (the shape of the phosphor particles is considered to reflect the quality of the crystallinity), the particle shape, high temperature and long time to improve the crystallinity If the effect on the activator element due to firing, additives, excessive grinding, Eu oxidation, etc. is large, the amount of activator element added at the first firing is added after the second activation. More than the amount of the agent element is not preferable.

  Further, even if considered from the principle, the activator element that penetrates into the voids does not disturb the crystal structure, and defects in the crystal structure can be reduced as much as possible, so in the first firing, it is preferable to limit the amount of the activator, The molar fraction of the activator element in the phosphor material for the first firing relative to the phosphor is 10% or less of the maximum value of the molar fraction of the activator element in the phosphor material for the second and subsequent firings relative to the phosphor. In particular, from the viewpoint of improving crystallinity, it is preferable that the activator element is not substantially contained.

Moreover, in the manufacturing method of this invention, the frequency | count of baking is not limited to 2 times, It can divide and implement in 3 times or more. Regarding the amount of the activator in this case, unless otherwise specified, the first addition is considered as the first addition, and the total after the second addition is regarded as the second addition amount.
Regarding firing conditions, the first firing for producing a β sialon matrix may be performed under conditions suitable for producing the target β sialon matrix. Specifically, in order to improve the crystallinity of β sialon and to properly configure the tube, it is kept at a high temperature such as 2000 ° C. where the β sialon does not decompose, for a long time, or at a temperature such as 1500 ° C. In order to adjust the particle size, firing may be performed at a low temperature, for example, 1700 ° C., which is not usually performed because the activator does not enter the host crystal.

The second and subsequent times may be performed under conditions suitable for introducing the activator element. Specifically, 1800 ° C. or higher, at which the activator element actively enters the β sialon matrix, is preferable. The second firing is not particularly limited as long as Eu is introduced.
When the activator element is Eu, the ionic radius of trivalent Eu is smaller than the ionic radius of divalent Eu. Therefore, Eu is added as a trivalent compound and enters the hexagonal tube described above. After that, it is considered that the valence is reduced from trivalent to divalent, and it is advisable to devise a temperature rising pattern corresponding to this.

  The production method of the present invention has a first firing step for mainly growing the base crystal with good crystallinity and a second and subsequent firing steps for introducing the activator into the phosphor, with a temperature pattern suitable for each purpose. Other than firing, a conventionally known method may be used as it is. A general method for producing β sialon will be described below.

(Phosphor raw material)
As the phosphor raw material used in the method for producing the phosphor of the present invention, known materials can be used, for example, silicon nitride (Si ₃ N ₄ ), aluminum nitride (AlN), and silicon oxide (SiO ₂ ). And / or aluminum oxide (Al ₂ O ₃ ) and further Eu-containing compounds such as Eu metals, oxides, carbonates, chlorides, fluorides, nitrides or oxynitrides.
Note that O (oxygen) and N (nitrogen) in the formula [1] may be supplied from a Si source, an Al source, and a Eu source, and N (nitrogen) may be supplied from a firing atmosphere. Each raw material may contain inevitable impurities.

In the case of the present invention, as described above, from the viewpoint of crystallinity, the phosphor material for the first firing does not contain an activator element-containing compound containing Eu as an activator, or reduce the amount thereof. Preferably, the second and subsequent firing phosphor materials are prepared by mixing the first fired powder and the activator element-containing compound containing Eu as the activator to produce the second firing phosphor material. .
In the production method of the present invention, the amount of the activator element added to the second firing phosphor material or the kind of the activator element-containing material is appropriately changed to adjust the luminescence chromaticity of the phosphor. Can do. The reason why the chromaticity can be adjusted by the kind of the activator element-containing raw material is considered to be because the activator to β sialon, especially the way of entering and the amount of Eu vary depending on the kind of the raw material.

(Mixing process)
In the production method of the present invention, the phosphor raw materials are usually weighed so as to obtain the target composition and sufficiently mixed using a ball mill or the like to obtain a phosphor raw material mixture (mixing step).
Although it does not specifically limit as said mixing method, Specifically, the method of following (A) and (B) is mentioned.

(A) Dry pulverizer such as hammer mill, roll mill, ball mill, jet mill, etc., or pulverization using mortar and pestle, and mixer such as ribbon blender, V-type blender, Henschel mixer, or mortar and pestle And a dry mixing method in which the above phosphor raw materials are pulverized and mixed.
(B) A solvent or dispersion medium such as water is added to the phosphor material described above, and mixed using, for example, a pulverizer, a mortar and a pestle, or an evaporating dish and a stirring rod, to obtain a solution or slurry. A wet mixing method in which drying is performed by spray drying, heat drying, or natural drying.
The mixing of the phosphor raw material may be either the wet mixing method or the dry mixing method, but in order to avoid contamination of the phosphor raw material with moisture, a dry mixing method or a wet mixing method using a water-insoluble solvent is more preferable. .

(Baking process)
Since the firing temperature varies depending on the desired phosphor composition, it cannot be generally specified, but in general, the phosphor can be stably obtained in a temperature range of 1800 ° C. or higher and 2200 ° C. or lower. If the heating temperature is 1800 ° C. or higher, Eu can enter the β-type sialon crystal, and a phosphor having sufficient luminance can be obtained. Further, if the heating temperature is 2200 ° C. or less, it is not necessary to suppress the decomposition of β-sialon by applying a very high nitrogen pressure, and therefore, a special apparatus is not required, which is industrially preferable. . As a preferable firing temperature, 1820 ° C. or higher is preferable, 1900 ° C. or higher is particularly preferable, and 2150 ° C. or lower is preferable.
2100 degrees C or less is especially preferable.

In the case of the present invention, it is not necessary to consider the activator entering the crystal during the first firing, so that a technique that is not suitable for causing the activator to emit light can be used. We can concentrate on adjusting the shape and crystallinity. Further, it can be fired even at a temperature lower than the temperature at which Eu enters β sialon, for example, a temperature of 1700 ° C. or lower. The conditions for the second firing are the same as in the above general theory.
The firing atmosphere in the firing step is arbitrary as long as the phosphor of the present invention is obtained, but is usually a nitrogen-containing atmosphere. Specific examples include a nitrogen atmosphere and a hydrogen-containing nitrogen atmosphere, and a nitrogen atmosphere is particularly preferable.

The oxygen content in the firing atmosphere is usually 10 ppm or less, preferably 5 ppm or less.
The rate of temperature increase is usually 2 ° C./min or more, preferably 3 ° C./min or more, and usually 20 ° C./min or less, preferably 15 ° C./min or less. If the rate of temperature rise is below this range, the firing time may be long. In addition, if the rate of temperature rise exceeds this range, the firing device, container, etc. may be damaged.

The firing time varies depending on the temperature, pressure and the like during firing, but is usually 10 minutes or longer, preferably 1 hour or longer, and usually 48 hours or shorter, preferably 36 hours or shorter, particularly preferably 24 hours or shorter.
The pressure during firing varies depending on the firing temperature and the like, but is usually 0.1 MPa or more, preferably 0.5 MPa or more, and the upper limit is usually 2 MPa or less, preferably 1.5 MPa or less. Of these, about 0.6 MPa to 1.2 MPa is industrially preferable in terms of cost and labor.

The obtained fired product is granular or massive. This is pulverized, pulverized and / or classified into a powder of a predetermined size. In the case of the present invention, β sialon after the first firing has a small amount of activator, and even if defects are introduced by pulverization or the like, the defects are removed to some extent by the subsequent second firing. For this reason, even when the image is strongly baked and excessive crushing is required, the light emission efficiency is unlikely to decrease. Therefore, it is preferable that the weight median diameter D _{50 is set} to 1 to 50 microns, more preferably 5 microns or more and an upper limit of 40 microns or less during the first firing at a low concentration of the activator (hereinafter referred to as “median diameter D”). “ ₅₀ ” is defined as follows: The median diameter D ₅₀ is a value obtained from a weight-based particle size distribution curve obtained by measuring the particle size distribution by a laser diffraction / scattering method. The phosphor is dispersed in an aqueous solution containing a dispersant, and measured by a laser diffraction particle size distribution measuring device (for example, Horiba LA-300) in a particle size range of 0.1 μm to 600 μm. In the weight-based particle size distribution curve, it means the particle size value when the integrated value is 50%.

(Heat treatment process)
It is preferable to heat-treat the phosphor obtained in the firing step at a temperature lower than the firing temperature (heat treatment step). This is to thermally decompose the impurity phase of oxynitride or the unstable oxynitride phase.
An appropriate heat treatment temperature varies depending on the atmosphere and the like, but a temperature range of 1200 ° C. or higher and 1550 ° C. or lower is preferable. The decomposition of the impurity phase tends to proceed at 1200 ° C. or higher, and the rapid decomposition of β-sialon can be suppressed at 1550 ° C. or lower.
Examples of the heat treatment atmosphere include a nitrogen atmosphere, a hydrogen-containing nitrogen atmosphere, an argon atmosphere, a hydrogen-containing argon atmosphere, and a vacuum atmosphere, and an argon atmosphere is preferable.

The pressure during the heat treatment varies depending on the heat treatment temperature and the like, but is usually 0.05 MPa or more, preferably 0.09 MPa or more, and the upper limit is usually 1 MPa or less, preferably 0.5 MPa or less. Of these, about 0.09 MPa to 0.3 MPa is industrially preferable in terms of cost and labor.
The heat treatment time varies depending on the temperature and pressure during the heat treatment, but is usually 10 minutes or longer, preferably 1 hour or longer, and usually 48 hours or shorter, preferably 24 hours or shorter.

  (In the case of the production method of the present invention, it is more effective to perform the heat treatment after adjusting the fired product to a predetermined particle size. This is because the amount of activator is small. Even when the particle size adjustment is performed after the second firing, the flux effect by the activator element is stronger than assumed at the second firing, and if a deviation from the target particle size occurs, pulverization may be necessary again In such a case, it is possible to remove not only crystal defects formed during firing but also crystal defects formed during crushing and pulverization required for particle size adjustment.)

(Washing process)
In general, β-type sialon phosphors tend to generate Si metal on the phosphor surface by thermal decomposition in a firing step or a heat treatment step. In order to improve the characteristics of the phosphor, it is necessary to remove this Si metal as much as possible. In the present invention, the cleaning method is not particularly limited as long as impurities can be removed. For example, cleaning can be performed using hydrofluoric acid and nitric acid. However, in consideration of safety, environmental load, and the like, (i) a solid at 20 ° C. and a solubility at 20 ° C. of 0.1. Using an aqueous solution A of fluoride of 01 g / water 100 ml or more and 400 g / water 100 ml or less, and (ii) an aqueous solution B containing at least one selected from the group consisting of nitric acid, sulfuric acid, hydrochloric acid, oxalic acid, and phosphoric acid To wash.

  In other words, hydrofluoric acid and nitric acid have been conventionally used as components of the mixed acid used in the cleaning process. However, in order to reduce the amount of hydrofluoric acid that is an acutely toxic substance, for example, sodium fluoride (melting point: A stable solid at 993 ° C.) and nitric acid. Thereby, impurities including the Si metal can be removed safely and efficiently, and the yield in the cleaning process can be improved, thereby improving industrial convenience. Compared with hydrofluoric acid, the aqueous solution A is safer for the human body, less burdens on the environment, and is easy to handle in work processes such as storage and transportation.

The solubility of the fluoride used in the aqueous solution A at 20 ° C. is usually 0.01 g / water 100 ml or more, preferably 0.1 g / water 100 ml or more, more preferably 0.5 g / water 100 ml or more, Usually, it is 400 g / 100 ml or less of water, preferably 100 g / 100 ml or less of water. Since it is solid at normal temperature, it is easy to handle and work and can be manufactured safely. Further, the aqueous solution A containing such a fluoride is corrosive with respect to impurities such as Si and SiO ₂ , so that these compounds can be removed by itself, but impurities such as Si and SiO ₂ are When coated with an impurity phase of nitride, it tends to be difficult to remove with the aqueous solution A alone, so at least one selected from the group consisting of nitric acid, sulfuric acid, hydrochloric acid, oxalic acid, and phosphoric acid By using together the aqueous solution B containing oxynitride, the impurity phase of oxynitride can be removed, and impurities such as Si and SiO ₂ can be efficiently removed.

Specific examples of the fluoride include LiF, NaF, KF, RbF, CsF, NH ₄ F, NaHF ₂ , KHF ₂ , RbHF ₂ , NH ₅ F ₂ , AlF ₃ , ZnF ₂ .4H ₂ O, ZrF. ₄ , Na ₂ TiF ₆ , K ₂ TiF ₆ , (NH ₄ ) ₂ TiF ₆ , Na ₂ SiF ₆ , K ₂ SiF ₆ , ZnSiF ₆ · 6H ₂ O, MgSiF ₆ · 6H ₂ O, Na ₂ ZrF ₆ , K ₂ ZrF ₆ , (NH ₄ ) ₂ ZrF ₆ , KBF ₄ , NH ₄ BF ₄ , Mg (BF ₄ ) 2 .6H ₂ O, KPF ₆ , K ₃ AlF ₆ , Na ₃ AlF ₆ , SrF ₂ etc. . Among those exemplified, NaF is preferable because of its moderately high solubility and low deliquescence.

The acid that can be used as the aqueous solution B is an inorganic acid other than hydrofluoric acid, and specifically, at least one selected from the group consisting of nitric acid, sulfuric acid, hydrochloric acid, oxalic acid, and phosphoric acid. (Hereinafter, these acids are referred to as “inorganic acids of aqueous solution B”). Of these, nitric acid is preferred because of its high oxidizing power.
The concentration of the inorganic acid in the aqueous solution B is generally 10% by weight or more, preferably 15% by weight or more, more preferably 20% by weight or more, and usually 70% by weight based on the total amount of the aqueous solution A and the aqueous solution B. % Or less. If the concentration of the inorganic acid in the aqueous solution B with respect to the total amount of the aqueous solution A and the aqueous solution B falls within the above range, the concentration of the inorganic acid in the aqueous solution B in the aqueous solution B is not particularly limited, and for example, dilute nitric acid or concentrated nitric acid is used. be able to.

As a combination of the aqueous solution A and the aqueous solution B, a combination of NaF and nitric acid is preferable. The dissolution treatment with these mixed aqueous solutions is preferable because Si can be quickly removed to improve the characteristics of the phosphor and workability and industrial convenience can be improved while reducing the environmental burden.
In the cleaning step of the present invention, the phosphor obtained in the firing step is immersed in a mixed solution of the aqueous solution A and the aqueous solution B. At this time, the mixing method is not particularly limited as long as the aqueous solution A and the aqueous solution B can be combined, and the aqueous solution B may be added to the aqueous solution A or the aqueous solution B.

Here, while it is immersed, it may be allowed to stand, but from the viewpoint of work efficiency, it is preferable to stir to such an extent that the cleaning time can be shortened. Moreover, although it normally works at room temperature, you may heat aqueous solution as needed.
The time for immersing the phosphor in the mixed solution of the aqueous solution A and the aqueous solution B varies depending on the stirring conditions and the like, but is usually 1 hour or more, preferably 2 hours or more, and usually 24 hours or less, preferably 12 Below time.
In the washing step, it is preferable to perform general water washing and filtration after the operation of immersing the phosphor in the mixed solution of the aqueous solution A and the aqueous solution B. As the cleaning medium in the water washing, water at room temperature (about 25 ° C.) is usually used, but it may be heated as necessary.

It is preferable to perform the water washing of the phosphor described above until the electrical conductivity of the supernatant liquid at the time becomes a predetermined value or less by performing the following water dispersion test on the washed phosphor. That is, the washed phosphor is pulverized or pulverized with a dry ball mill or the like, if necessary, and classified with a sieve or a water tank to adjust the particle size to a desired weight median diameter. Then, the phosphor particles having a specific gravity heavier than that of water are naturally precipitated by stirring and dispersing in water 10 times as much as the phosphor for a predetermined time, for example, 10 minutes, and then allowing to stand for 1 hour. The electrical conductivity of the supernatant liquid at this time is measured, and the above-described washing operation is performed as necessary until the electrical conductivity is usually 100 μS / cm or less, preferably 50 μS / cm or less, and most preferably 10 μS / cm or less. repeat.

  The water used for the water dispersion test of the phosphor is not particularly limited, but desalted water or distilled water is preferable in the same manner as the cleaning medium water, and the electrical conductivity is usually 0.01 μS / cm or more, preferably Is 0.1 μS / m or more, usually 10 μS / cm or less, preferably 1 μS / cm or less. The temperature of the water used for the water dispersion test of the phosphor is usually room temperature (about 25 ° C.).

The phosphor obtained by performing such washing has an electrical conductivity of usually 10 μS / cm or less of the supernatant obtained by dispersing the phosphor in water 10 times by weight and allowing it to stand for 1 hour.
In addition, the measurement of the electrical conductivity of the supernatant liquid in the water dispersion test of the phosphor can be performed using, for example, an electrical conductivity meter “ES-12” manufactured by Horiba, Ltd.
Moreover, after the said washing | cleaning process, it is made to use after making a fluorescent substance dry until there is no adhesion water | moisture content. Further, if necessary, dispersion / classification treatment may be performed to loosen the aggregation.

[Use of phosphor]
The phosphor obtained by the present invention can be used for any application using the phosphor. Moreover, although the phosphor obtained by the present invention can be used alone as the phosphor obtained by the present invention, two or more kinds of phosphors obtained by the present invention are used in combination or obtained by the present invention. It is also possible to use a phosphor mixture of any combination, such as a combination of a phosphor and another phosphor.

EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example, unless the summary is exceeded.
[Example 1]
Α-type silicon nitride powder (“SN-E10” grade, oxygen content 1.2% by mass, β phase content 4.5% by mass, carbon content less than 0.2% by mass) 96.00 mass by Ube Industries, Ltd. %, Tokuyama aluminum nitride powder (“E” grade, oxygen content 0.9 mass%, carbon content 0.03 mass%) 3.64 mass%, Admatech silicon oxide (SO-E5) 0. 36% by mass was weighed, and the above raw materials were mixed until they were sufficiently uniform.

  The obtained raw material mixture was filled in a boron nitride crucible having an outer diameter of 9 cm and a height of 10 cm, and fired by holding at 2025 ° C. for 18 hours in an atmosphere with a nitrogen pressure of 0.95 MPa. The obtained fired powder was passed through a nylon mesh (NMG23, mesh opening 900 μm) to obtain β-SiAlON without an activator. As a result of powder X-ray diffraction measurement, β-SiAlON without an activator was a β-sialon single phase. Β-SiAlON 99.19% by mass of the obtained activator and 0.81% by mass of europium oxide powder (“RU” grade) manufactured by Shin-Etsu Chemical Co., Ltd. were weighed, and nylon mesh (NMG23, mesh opening 900 μm) was measured * times. Pass to mix.

The obtained phosphor raw material mixture was fired by filling 300 g into a boron nitride crucible having an outer diameter of 6 cm and a height of 3.6 cm, and holding at 2000 ° C. for 12 hours under an atmosphere of nitrogen pressure of 0.95 MPa. A powder was prepared. Next, the fired powder was heat treated by holding it at 1450 ° C. for 12 hours under an atmosphere of argon pressure of 0.205 MPa, passing a nylon mesh (N-No. 305T, opening 48 μm), Obtained.
The obtained heat treated powder was washed and dried to obtain the phosphor of Example 1.

[Example 2]
Β-SiAlON 99.04 mass% without activator, europium fluoride powder (product of high purity chemical 9
9%) was obtained in the same manner as in Example 1 except that 0.96% by mass was measured so that the same charged Eu concentration as in Example 1 was obtained.
[Comparative Example 1]
Α-type silicon nitride powder (“SN-E10” grade, oxygen content 1.2 mass%, β β, manufactured by Ube Industries, Ltd.) so that the composition of the phosphor of Example 1 and the Si, Al, Eu concentration are the same. Phase content 4.5% by mass, carbon content less than 0.2% by mass) 95.22% by mass, aluminum nitride powder (“E” grade, oxygen content 0.9% by mass, carbon content 0 by Tokuyama Corporation) 0.03 mass%) 3.61 mass%, europium oxide powder manufactured by Shin-Etsu Chemical Co., Ltd. ("RU" grade) 0.81 mass%, admatech silicon oxide (SO-E5) 0.35 mass%, The above raw materials were mixed until sufficiently uniform.

25 g of the obtained phosphor raw material mixture was filled in a boron nitride crucible having an outer diameter of 6 cm and a height of 3.6 cm, and was fired by holding it at 2025 ° C. for 18 hours in an atmosphere with a nitrogen pressure of 1.0 MPa. A powder was prepared. Next, the fired powder was heat treated by holding it at 1450 ° C. for 12 hours under an atmosphere of argon pressure of 0.205 MPa, passing a nylon mesh (N-No. 305T, opening 48 μm), Obtained.
The obtained heat treated powder was washed and dried to obtain the phosphor of Comparative Example 1.

<Powder X-ray diffraction measurement>
Powder X-ray diffraction measurement of the phosphors of Examples 1 and 2 and Comparative Example 1 was performed using a CuKα X-ray source. Examples 1, 2 and Comparative Example 1 were β sialon single phase.
Comparison of Examples 1 and 2 in which the XRD pattern was translated so that the angle of the diffraction peak intensity on the (301) plane of β sialon was 0 °, and the diffraction intensity was normalized with the diffraction peak intensity on the (301) plane The diffraction pattern of the (301) plane of Example 1 is shown in FIG. Since the half widths of Examples 1 and 2 are narrower than those of Comparative Example 1, it can be seen that Examples 1 and 2 have better crystallinity than Comparative Example 1.
Table 1 shows values obtained by measuring the half widths of the (301) planes of Examples 1 and 2 and Comparative Example 1.

  In order to compare the crystallinity here, the diffraction peak of the (301) plane was used because when there are multiple equivalent planes, the peaks overlap and are inappropriate for the evaluation of crystallinity. In consideration of the fact that the accuracy is apt to be lowered when the Bragg angle 2θ is too low or high, the diffraction peak of the (301) plane near 2θ = 52 degrees is used.

表１から、Ｅｕ無しβサイアロンにＥｕ含有化合物を添加して焼成すると、半値幅が狭くなり、結晶性が良くなることがわかる。具体的には、Ｃｕ―Ｋα線にて測定した、ＸＲＤチャートの（３０１）面のピークの半値幅が、2θで０．１０５度より小さいβサイア
ロン蛍光体が得られている。より好ましくは０．１度以下である。そして、結晶性がよくなることで輝度が向上していることがわかる。
また、実施例１、２は色の違いに伴う、視感度を考慮すると、ほとんど同等の発光効率を有している。Ｅｕ含有化合物の種類が変更することによっても、効率をほとんど変化させることなく、発光の色度が変更できることがわかる。 <Relative brightness>
First, it measured using the fluorescence spectrophotometer F-4500 made from Hitachi, Ltd. at room temperature (25 degreeC). More specifically, the above-produced phosphor was irradiated with excitation light having a wavelength of 455 nm, and an emission spectrum within a wavelength range of 480 nm to 800 nm was obtained. From the obtained emission spectrum, the emission peak wavelength was read and the chromaticities x and y were calculated.
The luminance was calculated from the stimulus value Y in the XYZ color system calculated in accordance with JIS Z8724 in the range obtained by removing the excitation wavelength region from the emission spectrum in the visible region obtained by the above method. The luminances of the phosphors obtained in Examples 1 and 2 and Comparative Example 1 are shown in Table 1 as relative luminances when the luminance of the phosphor obtained in Comparative Example 1 is 100%.

From Table 1, it can be seen that when the Eu-containing compound is added to the Eu-free β sialon and fired, the half width is narrowed and the crystallinity is improved. Specifically, a β sialon phosphor having a half-value width of the peak on the (301) plane of the XRD chart measured by Cu—Kα ray is smaller than 0.105 degrees at 2θ. More preferably, it is 0.1 degrees or less. And it turns out that the brightness | luminance is improving because crystallinity improves.
In addition, Examples 1 and 2 have almost the same luminous efficiency in consideration of the visibility associated with the difference in color. It can be seen that the chromaticity of light emission can be changed with little change in efficiency even when the type of Eu-containing compound is changed.

  The phosphor manufactured by the manufacturing method of the present invention can be used in any field where light is used. For example, in addition to indoor and outdoor lighting, mobile phones, household appliances, outdoor installation displays, etc. It can be suitably used for image display devices of various electronic devices.

Claims (8)

  In the phosphor manufacturing method using β sialon as a host crystal, at least the firing step is performed twice, and in the first firing step, the phosphor material for the first firing that is less than the concentration to obtain the activator element The method for producing a β sialon phosphor is characterized by firing the phosphor material for the second firing in which the activator element is further added to the obtained first fired raw material. . The β sialon phosphor is represented by the following general formula. 2. The method for producing a β sialon phosphor according to claim 1.
_{Si 6-x Al x O x} N 8-x: Eu y ··· [1]
(In the formula, x and y represent numbers satisfying 0 ≦ x ≦ 4.2 and 0.001 ≦ y ≦ 0.03, respectively.)   The molar fraction of the activator element in the phosphor material for the first firing with respect to the phosphor is smaller than the sum of the mole fractions of the activator element in the phosphor material for the second and subsequent firings with respect to the phosphor. The method for producing a β sialon phosphor according to claim 1 or 2. The molar fraction of the activator element in the phosphor material for the first firing with respect to the phosphor is 10% or less of the maximum value of the mole fraction of the activator element in the phosphor material for the second and subsequent firings with respect to the phosphor. It exists, The manufacturing method of the beta sialon fluorescent substance of any one of Claim 1 thru | or 3 characterized by the above-mentioned.   The method for producing a β sialon phosphor according to any one of claims 1 to 4, wherein the activator element is substantially not contained in the phosphor material for the first firing.   A β sialon phosphor produced by the method according to claim 1. The half width of the peak on the (301) plane of the XRD chart measured with Cu-Kα ray is 2θ.
And β sialon phosphor less than 0.105 degrees.   A light emitting device using the phosphor according to claim 6.

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