JP2008101224A - Method for producing phosphor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a phosphor having a small particle diameter, a narrow particle diameter distribution and excellent emission intensity in a method for producing a phosphor by firing a phosphor precursor formed by using a liquid-phase process. <P>SOLUTION: In the method for producing a phosphor by forming a phosphor precursor in a liquid phase and firing the phosphor precursor, the method for producing the phosphor comprises a process for forming the phosphor precursor while performing a pH control in a range from pH 7 to pH 14 twice or more during a time from the beginning to the end of the formation of the phosphor precursor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a phosphor precursor produced using a liquid phase method, a phosphor produced by firing the phosphor precursor, and further to the phosphor precursor production apparatus. Furthermore, the present invention is a phosphor that can be suitably used for various flat panel displays such as plasma display panels, cathode ray tubes, fluorescent lamps, radiation intensifying screens, inkjet inks, electrophotographic toners, and silver halide photographic materials. About.

  In recent years, with the progress of the information society, various flat panel displays such as plasma display panels and color cathode ray tubes such as color cathode ray tubes have a large screen and high contrast, as symbolized by high-definition cathode ray tubes and high-definition display tubes. As the number of pixels increases, it is necessary to form finer pixels on the face plate so that a high-definition screen can be formed. For this reason, phosphors are required to improve various characteristics such as emission luminance and adhesion to the face plate surface.

  Conventional phosphors for flat panel displays use particles with a particle size of about 2 to 7 μm developed for color cathode ray tubes, and the development of excitation wavelengths optimized for each flat panel display has not progressed. Therefore, improvement of various characteristics is demanded. In particular, a phosphor having a small particle size, monodispersion, and high luminance is demanded as the display becomes more precise in the future.

  As a general phosphor manufacturing method, a solid phase method in which a predetermined amount of a compound containing an element constituting a phosphor matrix and a compound containing an activator element are mixed and then baked to perform a solid-solid reaction, and the phosphor matrix There is a liquid phase method in which a phosphor precursor precipitate obtained by mixing together a solution containing an element constituting the element and a solution containing an activator element is subjected to solid-liquid separation, followed by firing.

  In order to increase the luminous efficiency and yield of the phosphor, it is necessary to make the phosphor composition as close to the stoichiometric composition as possible, but the solid phase method produces a phosphor with a pure stoichiometric composition. Difficult to do. Since the solid-phase method is a reaction between solids, surplus impurities that do not react and sub-salts generated by the reaction often remain, and it is difficult to obtain a stoichiometrically high-purity phosphor.

  In addition, the phosphor obtained by the solid phase method has a relatively wide particle size distribution, and particularly when fired using a large amount of flux, a phosphor having a wide particle size distribution close to the normal distribution can be obtained. When a fluorescent film is formed using such a phosphor, it is not preferable that a large amount of fine particles and coarse particles exist in order to obtain a high-luminance and dense fluorescent film. These fine particles and coarse particles are removed by a classification operation as necessary, but the classification operation is poor in workability and decreases the yield. In particular, the formation of the coarse particles reduces the yield of particles having a desired particle size. It greatly affects and cannot always be removed reliably. Therefore, in forming a fluorescent film for a high-definition cathode ray tube, it is important not to generate unnecessary fine particles and coarse particles, particularly coarse particles, during firing.

  In addition, since the phosphor obtained by the solid-phase method has a lower luminous efficiency and emission luminance as the particle size becomes smaller, there are hardly any phosphors having sufficient emission efficiency and emission luminance below 1 μm. Is the actual situation. Several manufacturing methods relating to phosphors having a particle size of 1 μm or less have been disclosed. However, as in Patent Document 1, particles having a particle size of 1 μm or less are obtained by classification operation, and the phosphor brightness is reduced by the classification operation and the yield is reduced. The problem of degradation occurs.

  Further, in each process of manufacturing the phosphor, the aggregation increases the particle size of the particles, which has been a great hindrance to the atomization of the phosphor, but there are few inventions in terms of preventing this, and patents There is only a description of the sintering inhibitor in Document 2, etc., and the effect is not sufficient.

  On the other hand, when manufacturing a phosphor by a liquid phase method, first, a precipitate that is a phosphor precursor is generated, and then the phosphor precursor is baked to obtain a phosphor. In the liquid phase method, the reaction is caused by the element ions constituting the phosphor, so that it is easy to obtain a stoichiometrically high purity phosphor. However, the phosphor particle size, particle shape, particle size distribution, emission characteristics, etc. The characteristics greatly depend on the properties of the phosphor precursor. Therefore, in order to obtain a desired phosphor, it is necessary to consider the control of the particle shape and particle size distribution, the impurity exclusion, and the like during the production of the phosphor precursor.

Therefore, many improved methods relating to the production of phosphors by the liquid phase method have been proposed. For example, Patent Document 3 discloses a method for producing a rare earth phosphate phosphor for a fluorescent lamp by adding a solution in which rare earth element ions and phosphate ions coexist in an aqueous solution controlled to a pH of 1.0 to 2.0. It is disclosed to produce a phosphate phosphor precursor. Patent Document 4 discloses a method for producing a rare earth oxide by producing a spherical rare earth oxide by reacting a rare earth ion and an oxalate ion while maintaining the reaction between -5 ° C and 20 ° C. ing. However, these methods have advantages such as obtaining a high-purity composition and obtaining spherical particles as compared with the phosphor obtained by the solid phase method, but obtain a phosphor having both a small particle size and high luminance. It was still not enough.
JP-A-8-81678 JP-A-6-306358 JP 2001-172627 A Japanese Patent Laid-Open No. 9-71415

  The present invention relates to a method for producing a phosphor obtained by firing a phosphor precursor produced using a liquid phase method, wherein the particle size is small, the particle size distribution is narrow, and the emission intensity is good. A method for producing a phosphor is provided.

  As a result of intensive studies on a method for producing a phosphor by a liquid phase method in order to achieve the above object, the present inventors have determined that the particle diameter is small and the particle diameter is controlled by controlling the conditions for producing this phosphor precursor. It has been found that a phosphor having a narrow distribution and good emission intensity can be produced, and the present invention has been completed.

  The configuration of the present invention is as follows.

  (1) In the method for producing a phosphor, in which a phosphor is obtained by firing the phosphor precursor in the liquid phase and then firing the phosphor precursor, the time from the start to the end of the production of the phosphor precursor A method for producing a phosphor, comprising a step of generating a phosphor precursor while performing pH control twice or more in the range of pH 7 to pH 14.

  (2) The method for producing a phosphor according to (1), wherein the step of generating the phosphor precursor is performed in the presence of a binder.

  It was possible to provide a method for producing a phosphor having a small particle size, a narrow particle size distribution, and good emission intensity.

  Hereinafter, the present invention will be described in detail.

  The phosphor precursor is an intermediate product of the phosphor, and the phosphor is obtained by firing the phosphor precursor at a predetermined temperature.

  A method for producing the phosphor used in the present invention will be described.

  The present inventors control the production conditions of the phosphor precursor, particularly various conditions such as pH, temperature, ion concentration of phosphor precursor constituent elements, binder, etc., in the time from the start to the end of the production of the phosphor precursor. Thus, it has been found that a phosphor having a small particle size and a narrow particle size distribution and excellent emission intensity can be produced. As a method for producing the phosphor of the present invention, a solution containing an element constituting the phosphor matrix and a solution containing an activator element are mixed together to generate a precipitate of the phosphor precursor in the solution, and this phosphor precursor A liquid phase method in which the body is solid-liquid separated and then fired is preferably used.

  In the present invention, the method for precipitation of the phosphor precursor is not particularly limited, and it can be preferably produced by any method such as a reaction crystallization method, a coprecipitation method, or a Sol-Gel method. In addition, in order to obtain the type of phosphor and desired characteristics, it is preferable to appropriately adjust the addition speed and addition position of the raw material solution and the like, the stirring conditions, and the like.

  Although an example of the conceptual diagram of the production | generation apparatus of the fluorescent substance precursor in this invention is shown in FIG. 1, this invention is not limited to this example, All the aspects are used preferably. In FIG. 1, the container 1 initially contains the raw material solution [A]. The agitation mechanism 2 is illustrated as having a blade attached to a rotatable shaft, but this mechanism can have any conventional shape. While operating the stirring mechanism 2, the phosphor raw material solution [B] is poured into the container 1 through the pouring nozzle 3, and simultaneously, the phosphor raw material solution [C] is poured into the container 1 through the pouring nozzle 4. At this time, the characteristic value in the container 1 that changes with the reaction is measured by the sensor 6, and the necessary addition amount is fed back to the adjustment liquid adding device or the like (not shown) so as to obtain the desired characteristic value. The characteristic value is controlled in real time by pouring the adjustment liquid into the container 1 from the additive nozzle 5. The characteristic value does not need to be changed during the addition time of the raw material solution, and may be changed as needed. After completion of the addition of the raw material solution, the aging treatment is performed for a certain time, and the generation of the phosphor precursor is completed. At the time of aging, the characteristic values such as pH, temperature, ion concentration and the like may be the same as those at the time of adding the raw material solution, and may be appropriately changed as necessary.

  The raw material solution referred to in the present invention means a solution containing at least one of constituent element ions, a solvent or a binder of a phosphor.

  In the present invention, it is preferable to generate the phosphor precursor while controlling the pH of at least part of the time from the start to the end of the generation of the phosphor precursor, and further, while controlling the pH value in the range of pH 7 to pH 14. It is preferable to generate a phosphor precursor, and the most preferable embodiment is to generate a phosphor precursor by performing pH control at least twice.

  In addition, it is preferable to generate the phosphor precursor while controlling the temperature of at least a part of the time from the start to the end of the generation of the phosphor precursor. It is preferable to generate a phosphor precursor, and the most preferable embodiment is to generate a phosphor precursor by performing temperature control at least twice.

Furthermore, it is preferable to generate the phosphor precursor while controlling the ion concentration of at least one kind of constituent elements of the phosphor for at least part of the time from the start to the end of the generation of the phosphor precursor. It is more preferable to generate the phosphor precursor while controlling in the range of × 10 ⁻⁶ mol / l to 1 × 10 ² mol / l, and the phosphor precursor is generated by performing ion concentration control at least twice. Is the most preferred embodiment.

  In the present invention, the number of injection nozzles is not limited to three, but can be appropriately increased or decreased according to the type and characteristics of the phosphor to be manufactured. In the present invention, a pH sensor is preferably used as the sensor. Moreover, in another aspect, it is preferable to use a temperature sensor as what is used for a sensor. In yet another aspect, it is preferable to use an ion concentration sensor that measures at least one ion concentration of the constituent elements of the phosphor as the sensor. In a preferred embodiment of the present invention, the sensor is not limited to one type, but at least two types are used. Depending on the type and characteristics of the phosphor, pH, temperature, and ion concentration can be used in appropriate combination. Most preferably, all sensors are used to generate the phosphor precursor.

  In addition, crystal nuclei generated in a separate container in advance may be poured into the container 1, and crystal nuclei that have been continuously reacted in another mixer are continuously supplied to the container 1. There may be.

  In the present invention, the phosphor precursor is preferably generated in the presence of a binder. The binder in the present invention functions to prevent the particles from aggregating, and the function is clearly different from the organic polymer used for crystal habit control disclosed in JP-A-2001-329262.

  As the binder in the present invention, a known polymer compound can be used regardless of natural or synthetic. In that case, the average molecular weight of the binder is preferably 10,000 or more, more preferably 10,000 or more and 300,000 or less, and particularly preferably 10,000 or more and 30,000 or less. The binder in the present invention is preferably a protein, and particularly preferably gelatin. Moreover, it is not necessary to have a single composition, and various binders may be mixed.

  In the present invention, the solid-liquid separation method of the phosphor precursor is not particularly limited, and centrifugal separation, suction filtration method and the like are preferably used. Further, the phosphor precursor solution may be directly processed in a baking furnace such as a dryer or a spray pyrolysis furnace. In the present invention, the method for drying the phosphor precursor is not particularly limited, and any method such as vacuum drying, airflow drying, fluidized bed drying, spray drying and the like can be used.

  Further, in the present invention, the firing temperature and firing time of the phosphor precursor are not particularly limited, and can be appropriately selected according to the kind of the phosphor. The gas atmosphere at the time of firing may be any of an oxidizing atmosphere, a reducing atmosphere, and an inert atmosphere, and can be appropriately selected according to the purpose. Moreover, there is no limitation in particular as a baking apparatus, A well-known baking apparatus can be used. For example, a box furnace, a crucible furnace, a rotary kiln, a spray pyrolysis furnace or the like is preferably used.

In the present invention, an anti-caking agent may or may not be added. When added, it may be added as a slurry when the phosphor precursor is produced, and it is also preferably used in a method in which a powdery material is mixed with the dried phosphor precursor and fired. Further, the anti-caking agent is not particularly limited, and is appropriately selected depending on the type of phosphor and firing conditions. For example, depending on the firing temperature range of the phosphor, a metal oxide such as TiO ₂ is used for firing at 800 ° C. or less, SiO ₂ is used for firing at 1,000 ° C. or less, and for firing at 1,700 ° C. or less. Al ₂ O ₃ is preferably used. In the present invention, it is desirable to wash the phosphor after firing, but it is not always necessary to wash it.

  The phosphor according to the present invention preferably has an average particle size of 1.0 μm or less, more preferably 0.8 μm or less, further preferably 0.5 μm or less, and 0.01 μm or more and 0.0. Most preferably, it is 3 μm or less. The average particle diameter shown here refers to the length of the edge of the particle when the particle is a so-called normal crystal of a cube or octahedron. In the case of non-normal crystals, for example, in the case of spherical, rod-like, or tabular grains, the diameter when a sphere equivalent to the volume of the grains is considered is shown.

  In the present invention, the shape of the phosphor particles is not particularly limited, but a cubic shape is preferable, an octahedral shape is more preferable, and a spherical shape is more preferable.

  In the phosphor of the present invention, the variation coefficient of the particle size distribution is preferably 100% or less, more preferably 50% or less, and most preferably 30% or less. Here, the variation coefficient of the particle size is a value defined by the following equation.

(Standard deviation of particle size / average value of particle size) × 100 = width of particle distribution (coefficient of variation) [%]
In the present invention, the phosphor may be subjected to surface modification or improvement of dispersibility as required by a surface modifying agent, a surfactant, a matting agent such as fine particle silica gel, aerosil, or alumina.

The composition of the inorganic phosphor particles according to the present invention is described in, for example, JP-A Nos. 50-6410, 61-65226, 64-22987, 64-60671, and JP-A-1-168911. Although there is no particular limitation, it is represented by metal oxides typified by Y ₂ O ₂ S, Zn ₂ SiO ₄ , Ca ₅ (PO ₄ ) ₃ Cl, etc. which are crystal bases, and ZnS, SrS, CaS, etc. Activates ions of rare earth metals such as Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb, and metals such as Ag, Al, Mn, and Sb. What combined as an agent or a co-activator is preferable.

Preferred examples of the crystal matrix include, for example, ZnS, Y ₂ O ₂ S, Y ₃ Al ₅ O ₁₂ , Y ₂ SiO ₅ , Zn ₂ SiO ₄ , Y ₂ O ₃ , BaMgAl ₁₀ O ₁₇ , BaAl ₁₂ O ₁₉ , (Ba, Sr, Mg) O.BaAl ₂ O ₃ , (Y, Gd) BO ₃ , YO ₃ , (Zn, Cd) S, SrGa ₂ S ₄ , SrS, GaS, SnO ₂ , Ca ₁₀ (PO ₄ ) ₆ (F, Cl) ₂ , (Ba, Sr) (Mg, Mn) Al ₁₀ O ₁₇ , (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ , (La, Ce) PO ₄ , CeMgAl _{11 O 19, GdMgB 5 O 10} , Sr 2 P 2 O 7, Sr 4 Al 14 O 25 and the like.

  The above crystal matrix and activator or coactivator may be partially replaced with elements of the same family, and the element composition is not particularly limited.

  Although the example of a compound of inorganic fluorescent substance particle is shown below, this invention is not limited to these compounds.

[Blue light emitting inorganic fluorescent compound]
(BL-1) Sr ₂ P ₂ O ₇ : Sn ⁴⁺
(BL-2) Sr ₄ Al ₁₄ O ₂₅ : Eu ²⁺
(BL-3) BaMgAl ₁₀ O ₁₇ : Eu ²⁺
(BL-4) SrGa ₂ S ₄ : Ce ³⁺
(BL-5) CaGa ₂ S ₄ : Ce ³⁺
(BL-6) (Ba, Sr) (Mg, Mn) Al ₁₀ O ₁₇ : Eu ²⁺
(BL-7) (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺
(BL-8) ZnS: Ag
(BL-9) CaWO ₄
(BL-10) Y ₂ SiO ₅ : Ce ³⁺
(BL-11) ZnS: Ag, Ga, Cl
(BL-12) Ca ₂ B ₅ O ₉ Cl: Eu ²⁺
(BL-13) BaMgAl ₁₄ O ₂₃ : Eu ²⁺
(BL-14) BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , Tb ³⁺ , Sm ²⁺
(BL-15) BaMgAl ₁₄ O ₂₃ : Sm ²⁺
(BL-16) Ba ₂ Mg ₂ Al ₁₂ O ₂₂ : Eu ²⁺
(BL-17) Ba ₂ Mg ₄ Al ₈ O ₁₈ : Eu ²⁺
(BL-18) Ba ₃ Mg ₅ Al ₁₈ O ₃₅ : Eu ²⁺
(BL-19) (Ba, Sr, Ca) (Mg, Zn, Mn) Al ₁₀ O ₁₇ : Eu ²⁺
[Green emitting inorganic phosphor particles]
(GL-1) (Ba, Mg) Al ₁₆ O ₂₇ : Eu ²⁺ , Mn ²⁺
(GL-2) Sr ₄ Al ₁₄ O ₂₅ : Eu ²⁺
(GL-3) (Sr, Ba) Al ₂ Si ₂ O ₈ : Eu ²⁺
(GL-4) (Ba, Mg) ₂ SiO ₄ : Eu ²⁺
_{(GL-5) Y 2 SiO} 5: Ce 3+, Tb 3+
(GL-6) Sr ₂ P ₂ O ₇ —Sr ₂ B ₂ O ₅ : Eu ²⁺
(GL-7) (Ba, Ca, Mg) ₅ (PO ₄ ) ₃ Cl: Eu ²⁺
_{(GL-8) Sr 2 Si} 3 O 8 - 2 SrCl 2: Eu 2+
_{(GL-9) Zr 2 SiO} 4, MgAl 11 O 19: Ce 3+, Tb 3+
(GL-10) Ba ₂ SiO ₄ : Eu ²⁺
(GL-11) ZnS: Cu, Al
(GL-12) (Zn, Cd) S: Cu, Al
(GL-13) ZnS: Cu, Au, Al
(GL-14) Zn ₂ SiO ₄ : Mn ²⁺
(GL-15) ZnS: Ag, Cu
(GL-16) (Zn, Cd) S: Cu
(GL-17) ZnS: Cu
(GL-18) Gd ₂ O ₂ S: Tb ³⁺
(GL-19) La ₂ O ₂ S: Tb ³⁺
(GL-20) Y ₂ SiO ₅ : Ce ³⁺ , Tb ³⁺
(GL-21) Zn ₂ GeO ₄ : Mn ²⁺
(GL-22) CeMgAl ₁₁ O ₁₉ : Tb ³⁺
(GL-23) SrGa ₂ S ₄ : Eu ²⁺
(GL-24) ZnS: Cu, Co
(GL-25) MgO.nB ₂ O ₃ : Ce ³⁺ , Tb ³⁺
(GL-26) LaOBr: Tb ³⁺ , Tm ³⁺
(GL-27) La ₂ O ₂ S: Tb ³⁺
(GL-28) SrGa ₂ S ₄ : Eu ²⁺ , Tb ³⁺ , Sm ²⁺
[Red light emitting inorganic phosphor particles]
(RL-1) Y ₂ O ₂ S: Eu ³⁺
(RL-2) (Ba, Mg) ₂ SiO ₄ : Eu ³⁺
(RL-3) Ca ₂ Y ₈ (SiO ₄ ) ₆ O ₂ : Eu ³⁺
(RL-4) LiY ₉ (SiO ₄ ) ₆ O ₂ : Eu ³⁺
(RL-5) (Ba, Mg) Al ₁₆ O ₂₇ : Eu ³⁺
(RL-6) (Ba, Ca, Mg) ₅ (PO ₄ ) ₃ Cl: Eu ³⁺
(RL-7) YVO ₄ : Eu ³⁺
(RL-8) YVO ₄ : Eu ³⁺ , Bi ³⁺
(RL-9) CaS: Eu ³⁺
(RL-10) Y ₂ O ₃ : Eu ³⁺
(RL-11) 3.5MgO, 0.5MgF ₂ GeO ₂ : Mn ⁴⁺
(RL-12) YAlO ₃ : Eu ³⁺
(RL-13) YBO ₃ : Eu ³⁺
(RL-14) (Y, Gd) BO ₃ : Eu ³⁺
etc.

  Below, the use of the phosphor according to the present invention is exemplified, but the present invention is not limited to this. Inorganic phosphors according to the present invention include phosphors for flat panel displays such as plasma display panels, field emission displays, ultraviolet light emitting organic electroluminescence displays, phosphors for color cathode ray tubes, inkjet inks, electrophotographic toners, halogenated substances. It can be used as a color material such as silver photographic material, a phosphor for media, and a phosphor for intensifying screens.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this.

(Example 1)
<Manufacture of phosphor 1>
1,000 ml of water was used as the solution [A]. Yttrium nitrate hexahydrate, gadolinium nitrate, nitric acid so that the yttrium ion concentration is 0.4659 mol / l, the gadolinium ion concentration is 0.2716 mol / l, and the europium ion concentration is 0.0388 mol / l in 500 ml of water. Europium hexahydrate was dissolved to obtain a solution [B]. Boric acid was dissolved in 500 ml of water so that the ion concentration of boron was 0.7763 mol / l to obtain a solution [C].

  The solution [A] was placed in the container 1 of FIG. 1 and stirred using the stirring mechanism 2. In that state, the solution [B] and the solution [C] were added at a constant rate of 100 ml / min from the pouring nozzles 3 and 4 of the container 1 containing the solution [A], respectively. After the addition, aging was performed for 45 minutes to obtain phosphor precursor 1. Thereafter, the phosphor precursor 1 was filtered and dried to obtain a dried phosphor precursor 1. Furthermore, the dried phosphor precursor 1 was baked for 2 hours under oxidizing conditions at 1,400 ° C. to obtain phosphor 1.

<Manufacture of phosphor 2>
A solution [A] was prepared by adding nitric acid to 1,000 ml of water to adjust the pH to 5.5. Yttrium nitrate hexahydrate, gadolinium nitrate, nitric acid so that the yttrium ion concentration is 0.4659 mol / l, the gadolinium ion concentration is 0.2716 mol / l, and the europium ion concentration is 0.0388 mol / l in 500 ml of water. Europium hexahydrate was dissolved to obtain a solution [B]. Boric acid was dissolved in 500 ml of water so that the ion concentration of boron was 0.7763 mol / l to obtain a solution [C].

  The solution [A] was placed in the container 1 of FIG. 1 and stirred using the stirring mechanism 2. In this state, the solution [B] and the solution [C] were respectively added at a constant rate of 100 ml / min from the pouring nozzles 3 and 4 of the container 1 containing the solution [A] to obtain a white precipitate. At this time, a signal from the sensor 6 (in this case, a pH sensor is used) is fed back to an ammonia addition device (not shown), and the reaction is performed by controlling the pH to 5.5 while adding ammonia from the pouring nozzle 5. went. After completion of the addition, aging was performed for 45 minutes to obtain phosphor precursor 2. Thereafter, the phosphor precursor 2 was filtered and dried to obtain a dried phosphor precursor 2. Furthermore, the dried phosphor precursor 2 was baked for 2 hours under oxidizing conditions at 1,400 ° C. to obtain phosphor 2.

<Manufacture of phosphor 3>
A solution [A] was prepared by adding ammonia to 1,000 ml of water to adjust the pH to 8.0. Yttrium nitrate hexahydrate, gadolinium nitrate, nitric acid so that the yttrium ion concentration is 0.4659 mol / l, the gadolinium ion concentration is 0.2716 mol / l, and the europium ion concentration is 0.0388 mol / l in 500 ml of water. Europium hexahydrate was dissolved to obtain a solution [B]. Boric acid was dissolved in 500 ml of water so that the ion concentration of boron was 0.7763 mol / l to obtain a solution [C].

  The solution [A] was placed in the container 1 of FIG. 1 and stirred using the stirring mechanism 2. In this state, the solution [B] and the solution [C] were respectively added at a constant rate of 100 ml / min from the pouring nozzles 3 and 4 of the container 1 containing the solution [A] to obtain a white precipitate. At this time, a signal from the sensor 6 (in this case, a pH sensor is used) is fed back to an ammonia adding device (not shown), and the reaction is performed by controlling the pH to 8.0 while adding ammonia from the pouring nozzle 5. went. After completion of the addition, aging was performed for 45 minutes to obtain phosphor precursor 3. Thereafter, the phosphor precursor 3 was filtered and dried to obtain a dried phosphor precursor 3. Furthermore, the dried phosphor precursor 3 was baked for 2 hours under oxidizing conditions at 1,400 ° C. to obtain phosphor 3.

<Manufacture of phosphor 4>
A solution [A] was prepared by adding ammonia to 1,000 ml of water to adjust the pH to 8.0. Yttrium nitrate hexahydrate, gadolinium nitrate, nitric acid so that the yttrium ion concentration is 0.4659 mol / l, the gadolinium ion concentration is 0.2716 mol / l, and the europium ion concentration is 0.0388 mol / l in 500 ml of water. Europium hexahydrate was dissolved to obtain a solution [B]. Boric acid was dissolved in 500 ml of water so that the ion concentration of boron was 0.7763 mol / l to obtain a solution [C].

  The solution [A] was placed in the container 1 of FIG. 1 and stirred using the stirring mechanism 2. In this state, the solution [B] and the solution [C] were respectively added at a constant rate of 100 ml / min from the pouring nozzles 3 and 4 of the container 1 containing the solution [A] to obtain a white precipitate. At this time, a signal from the sensor 6 (in this case, a pH sensor is used) is fed back to an ammonia adding device (not shown), and the reaction is performed by controlling the pH to 8.0 while adding ammonia from the pouring nozzle 5. went. After completion of the addition, the pH was set to 11.0 using ammonia and aging was performed for 45 minutes to obtain phosphor precursor 4. During aging, the signal from the sensor 6 was fed back to an ammonia addition device (not shown), and the pH was controlled to 11.0 while appropriately adding ammonia. Thereafter, the phosphor precursor 4 was filtered and dried to obtain a dried phosphor precursor 4. Furthermore, the dried phosphor precursor 4 was baked for 2 hours under oxidizing conditions at 1,400 ° C. to obtain the phosphor 4.

<Manufacture of phosphor 5>
Phosphor 5 was obtained in the same manner as phosphor 2 except that a solution obtained by dissolving 30 g of low molecular gelatin (average molecular weight of about 100,000) in 1,000 ml of water was used as solution [A].

<Manufacture of phosphor 6>
Phosphor 6 was obtained in the same manner as phosphor 3 except that a solution obtained by dissolving 30 g of low molecular gelatin (average molecular weight of about 100,000) in 1,000 ml of water was used as solution [A].

<Manufacture of phosphor 7>
Phosphor 7 was obtained in the same manner as phosphor 4 except that a solution obtained by dissolving 30 g of low molecular gelatin (average molecular weight of about 100,000) in 1,000 ml of water was used as solution [A].

As a result of confirming the composition of the obtained phosphors 1 to 7 with a powder X-ray diffractometer, it was (Y, Gd) BO ₃ : Eu ³⁺ . The phosphors (phosphors 1 to 7) were irradiated with vacuum ultraviolet rays (146 nm), and the respective emission intensities were determined. Next, the relative light emission intensity of each phosphor when the phosphor 1 was 100% was calculated. Moreover, the particle diameter was taken with the electron microscope, and the average particle diameter and the variation coefficient were computed. The results are shown in Table 1.

  As can be seen from Table 1, it was possible to obtain a phosphor having a small particle size, monodispersion and high emission intensity by using the production method of the present invention.

(Example 2)
<Manufacture of phosphor 8>
Sodium metasilicate was dissolved in 800 ml of water so that the ion concentration of silicon was 0.4655 mol / l to obtain a solution [A]. Zinc chloride was dissolved in 800 ml of water so that the ion concentration of zinc was 0.8845 mol / l to obtain a solution [B]. Manganese chloride tetrahydrate was dissolved in 200 ml of water so that the manganese ion concentration was 0.1862 mol / l to obtain a solution [C].

  The solution [A] was placed in the container 1 of FIG. 1 and stirred using the stirring mechanism 2. In this state, the solution [B] is added at a rate of 80 ml / min and the solution [C] is added at a rate of 20 ml / min from the pouring nozzles 3 and 4 of the container 1 containing the solution [A]. It was. After the addition, aging was performed for 120 minutes to obtain phosphor precursor 8. Thereafter, the phosphor precursor 8 was filtered and dried to obtain a dried phosphor precursor 8. Further, the dried phosphor precursor 8 was baked for 3 hours in a nitrogen atmosphere at 1,050 ° C. to obtain a phosphor 8.

<Manufacture of phosphor 9>
Sodium metasilicate was dissolved in 800 ml of water so that the ion concentration of silicon was 0.4655 mol / l to obtain a solution [A]. Zinc chloride was dissolved in 800 ml of water so that the ion concentration of zinc was 0.8845 mol / l to obtain a solution [B]. Manganese chloride tetrahydrate was dissolved in 200 ml of water so that the manganese ion concentration was 0.1862 mol / l to obtain a solution [C].

  The solution [A] was placed in the container 1 of FIG. 1 and stirred using the stirring mechanism 2. In this state, the solution [B] is added at a rate of 80 ml / min and the solution [C] is added at a rate of 20 ml / min from the pouring nozzles 3 and 4 of the container 1 containing the solution [A]. It was. After the addition, aging was performed for 120 minutes to obtain a phosphor precursor 9. At this time, a signal from the sensor 6 (in this case, a pH sensor is used) is fed back to a nitric acid addition device (not shown), and the reaction is performed by controlling the pH to 6.5 while adding nitric acid from the pouring nozzle 5. went. After completion of the addition, aging was performed for 120 minutes to obtain a phosphor precursor 9. Thereafter, the phosphor precursor 9 was filtered and dried to obtain a dried phosphor precursor 9. Further, the dried phosphor precursor 9 was baked for 3 hours in a nitrogen atmosphere at 1,050 ° C. to obtain a phosphor 9.

<Manufacture of phosphor 10>
Sodium metasilicate was dissolved in 800 ml of water so that the ion concentration of silicon was 0.4655 mol / l to obtain a solution [A]. Zinc chloride was dissolved in 800 ml of water so that the ion concentration of zinc was 0.8845 mol / l to obtain a solution [B]. Manganese chloride tetrahydrate was dissolved in 200 ml of water so that the manganese ion concentration was 0.1862 mol / l to obtain a solution [C].

  The solution [A] was placed in the container 1 of FIG. 1 and stirred using the stirring mechanism 2. In this state, the solution [B] is added at a rate of 80 ml / min and the solution [C] is added at a rate of 20 ml / min from the pouring nozzles 3 and 4 of the container 1 containing the solution [A]. It was. At this time, a signal from the sensor 6 (in this case, a pH sensor is used) is fed back to an ammonia adding device (not shown), and the reaction is controlled by controlling the pH to 11.0 while adding ammonia from the pouring nozzle 5. went. After completion of the addition, aging was performed for 120 minutes to obtain phosphor precursor 10. Thereafter, the phosphor precursor 10 was filtered and dried to obtain a dried phosphor precursor 10. Further, the dried phosphor precursor 10 was baked for 3 hours in a nitrogen atmosphere at 1,050 ° C. to obtain the phosphor 10.

<Manufacture of phosphor 11>
Sodium metasilicate was dissolved in 800 ml of water so that the ion concentration of silicon was 0.4655 mol / l to obtain a solution [A]. Zinc chloride was dissolved in 800 ml of water so that the ion concentration of zinc was 0.8845 mol / l to obtain a solution [B]. Manganese chloride tetrahydrate was dissolved in 200 ml of water so that the manganese ion concentration was 0.1862 mol / l to obtain a solution [C].

  The solution [A] was placed in the container 1 of FIG. 1 and stirred using the stirring mechanism 2. In this state, the solution [B] is added at a rate of 80 ml / min and the solution [C] is added at a rate of 20 ml / min from the pouring nozzles 3 and 4 of the container 1 containing the solution [A]. It was. At this time, a signal from the sensor 6 (in this case, a pH sensor is used) is fed back to an ammonia adding device (not shown), and the reaction is controlled by controlling the pH to 11.0 while adding ammonia from the pouring nozzle 5. went. After completion of the addition, the pH was adjusted to 13.0 using ammonia and aging was performed for 120 minutes to obtain phosphor precursor 11. During aging, the signal from the sensor 6 was fed back to an ammonia addition device (not shown), and the pH was controlled to 13.0 while appropriately adding ammonia from the pouring nozzle 5. Thereafter, the phosphor precursor 11 was filtered and dried to obtain a dried phosphor precursor 11. Further, the dried phosphor precursor 11 was baked for 3 hours in a nitrogen atmosphere at 1,050 ° C. to obtain a phosphor 11.

<Manufacture of phosphor 12>
Except that 3% by mass of low molecular gelatin (average molecular weight of about 100,000) was added to each of the solution [A], the solution [B], and the solution [C] and dissolved, fluorescence was obtained in the same manner as the method for manufacturing the phosphor 9. Body 12 was obtained.

<Manufacture of phosphor 13>
Except that 3% by mass of low molecular gelatin (average molecular weight of about 100,000) was added to each of the solution [A], the solution [B], and the solution [C] and dissolved, fluorescence was obtained in the same manner as the method for manufacturing the phosphor 10. Body 13 was obtained.

<Manufacture of phosphor 14>
Except that 3% by mass of low molecular gelatin (average molecular weight of about 100,000) was added to each of the solution [A], the solution [B], and the solution [C] and dissolved, fluorescence was obtained in the same manner as the method for manufacturing the phosphor 11. Body 14 was obtained.

The obtained phosphors 8 to 14 were Zn ₂ SiO ₄ : Mn ²⁺ as a result of confirming the composition with a powder X-ray diffractometer. The phosphors (phosphors 8 to 14) were irradiated with vacuum ultraviolet rays (146 nm), and the emission intensity of each was determined. Next, the relative light emission intensity of each phosphor when the phosphor 8 was 100% was calculated. Moreover, the particle diameter was taken with the electron microscope, and the average particle diameter and the variation coefficient were computed. The results are shown in Table 2.

  As is apparent from Table 2, it was possible to obtain a phosphor having a small particle size, monodispersion and high emission intensity by using the production method of the present invention.

(Reference example)
<Manufacture of phosphor 15>
1,000 ml of water was used as the solution [A]. Yttrium nitrate hexahydrate, gadolinium nitrate, nitric acid so that the yttrium ion concentration is 0.4659 mol / l, the gadolinium ion concentration is 0.2716 mol / l, and the europium ion concentration is 0.0388 mol / l in 500 ml of water. Europium hexahydrate was dissolved to obtain a solution [B]. Boric acid was dissolved in 500 ml of water so that the ion concentration of boron was 0.7763 mol / l to obtain a solution [C].

  The solution [A] was placed in the container 1 of FIG. 1 and the temperature was kept at 15 ° C., and stirring was performed using the stirring mechanism 2. In this state, the solution [B] and the solution [C], which were also kept at 15 ° C., were added at a constant rate of 100 ml / min from the pouring nozzles 3 and 4 of the container 1 containing the solution [A], and white precipitates were added. Got. At this time, a signal from the sensor 6 (in this case, a temperature sensor was used) was fed back to a temperature controller (not shown), and the reaction was performed while controlling at 15 ° C. After completion of the addition, aging was performed for 45 minutes to obtain a phosphor precursor 15. Thereafter, the phosphor precursor 15 was filtered and dried to obtain a dried phosphor precursor 15. Furthermore, the dried phosphor precursor 15 was baked for 2 hours under oxidizing conditions at 1,400 ° C. to obtain a phosphor 15.

<Manufacture of phosphor 16>
1,000 ml of water was used as the solution [A]. Yttrium nitrate hexahydrate, gadolinium nitrate, nitric acid so that the yttrium ion concentration is 0.4659 mol / l, the gadolinium ion concentration is 0.2716 mol / l, and the europium ion concentration is 0.0388 mol / l in 500 ml of water. Europium hexahydrate was dissolved to obtain a solution [B]. Boric acid was dissolved in 500 ml of water so that the ion concentration of boron was 0.7763 mol / l to obtain a solution [C].

  The solution [A] was placed in the container 1 of FIG. 1 and the temperature was kept at 45 ° C., and stirring was performed using the stirring mechanism 2. In this state, the solution [B] and the solution [C], which were also kept at 45 ° C., were added at a constant rate of 100 ml / min from the pouring nozzles 3 and 4 of the container 1 containing the solution [A], and white precipitates were added. Got. At this time, a signal from the sensor 6 (in this case, a temperature sensor was used) was fed back to a temperature controller (not shown), and the reaction was performed while controlling at 45 ° C. After completion of the addition, aging was performed for 45 minutes to obtain a phosphor precursor 16. Thereafter, the phosphor precursor 16 was filtered and dried to obtain a dry phosphor precursor 16. Furthermore, the dried phosphor precursor 16 was baked for 2 hours under oxidizing conditions at 1,400 ° C. to obtain a phosphor 16.

<Manufacture of phosphor 17>
1,000 ml of water was used as the solution [A]. Yttrium nitrate hexahydrate, gadolinium nitrate, nitric acid so that the yttrium ion concentration is 0.4659 mol / l, the gadolinium ion concentration is 0.2716 mol / l, and the europium ion concentration is 0.0388 mol / l in 500 ml of water. Europium hexahydrate was dissolved to obtain a solution [B]. Boric acid was dissolved in 500 ml of water so that the ion concentration of boron was 0.7763 mol / l to obtain a solution [C].

  The solution [A] was placed in the container 1 of FIG. 1 and the temperature was kept at 45 ° C., and stirring was performed using the stirring mechanism 2. In this state, the solution [B] and the solution [C], which were also kept at 45 ° C., were added at a constant rate of 100 ml / min from the pouring nozzles 3 and 4 of the container 1 containing the solution [A], and white precipitates were added. Got. At this time, a signal from the sensor 6 (in this case, a temperature sensor was used) was fed back to a temperature controller (not shown), and the reaction was performed while controlling at 45 ° C. After completion of the addition, the mixture was heated to 80 ° C. and aged for 45 minutes to obtain phosphor precursor 17. During aging, the signal from the sensor 6 was fed back to a temperature control device (not shown) and controlled to 80 ° C. Thereafter, the phosphor precursor 17 was filtered and dried to obtain a dried phosphor precursor 17. Furthermore, the dried phosphor precursor 17 was baked for 2 hours under oxidizing conditions at 1,400 ° C. to obtain a phosphor 17.

<Manufacture of phosphor 18>
Phosphor 18 was obtained in the same manner as phosphor 15 except that 30 g of low molecular gelatin (average molecular weight of about 100,000) was dissolved in 1,000 ml of water to prepare solution [A].

<Manufacture of phosphor 19>
Phosphor 19 was obtained in the same manner as phosphor 16 except that 30 g of low molecular gelatin (average molecular weight of about 100,000) was dissolved in 1,000 ml of water to prepare solution [A].

<Manufacture of phosphor 20>
Phosphor 20 was obtained in the same manner as phosphor 17 except that 30 g of low molecular gelatin (average molecular weight of about 100,000) was dissolved in 1,000 ml of water to prepare solution [A].

As a result of confirming the composition of the obtained phosphors 15 to 20 with a powder X-ray diffractometer, it was (Y, Gd) BO ₃ : Eu ³⁺ . The phosphors (phosphors 15 to 20) were irradiated with vacuum ultraviolet rays (146 nm), and the emission intensity of each was determined. Next, the relative light emission intensity of each phosphor when the phosphor 1 produced in Example 1 was taken as 100% was calculated. Moreover, the particle diameter was taken with the electron microscope, and the average particle diameter and the variation coefficient were computed. The results are shown in Table 3.

  As is apparent from Table 3, it was possible to obtain a phosphor having a small particle size, monodispersion and high emission intensity by generating the phosphor precursor while controlling the temperature.

(Reference example)
<Manufacture of phosphor 21>
Sodium metasilicate was dissolved in 800 ml of water so that the ion concentration of silicon was 0.4655 mol / l to obtain a solution [A]. Zinc chloride was dissolved in 800 ml of water so that the ion concentration of zinc was 0.8845 mol / l to obtain a solution [B]. Manganese chloride tetrahydrate was dissolved in 200 ml of water so that the manganese ion concentration was 0.1862 mol / l to obtain a solution [C].

  The solution [A] was placed in the container 1 of FIG. 1 and the temperature was kept at 25 ° C., and stirring was performed using the stirring mechanism 2. In this state, the solution [B] kept at 25 ° C. at the rate of 80 ml / min from the pouring nozzles 3 and 4 of the container 1 containing the solution [A] is kept at 25 ° C. Was added at a constant rate of 20 ml / min. After the addition, aging was performed for 120 minutes to obtain a phosphor precursor 21. Thereafter, the phosphor precursor 21 was filtered and dried to obtain a dried phosphor precursor 21. Furthermore, the dried phosphor precursor 21 was baked for 3 hours in a nitrogen atmosphere at 1,050 ° C. to obtain a phosphor 21.

<Manufacture of phosphor 22>
Sodium metasilicate was dissolved in 800 ml of water so that the ion concentration of silicon was 0.4655 mol / l to obtain a solution [A]. Zinc chloride was dissolved in 800 ml of water so that the ion concentration of zinc was 0.8845 mol / l to obtain a solution [B]. Manganese chloride tetrahydrate was dissolved in 200 ml of water so that the manganese ion concentration was 0.1862 mol / l to obtain a solution [C].

  The solution [A] was placed in the container 1 of FIG. 1, and the temperature was maintained at 55 ° C., and stirring was performed using the stirring mechanism 2. In this state, the solution [B] kept at 55 ° C. from the pouring nozzles 3 and 4 of the container 1 containing the solution [A] was kept at 55 ° C. at a rate of 80 ml / min. Was added at a constant rate of 20 ml / min. After the addition, aging was performed for 120 minutes to obtain a phosphor precursor 22. At this time, a signal from the sensor 6 (in this case, a temperature sensor was used) was fed back to a temperature controller (not shown), and the reaction was performed while controlling at 55 ° C. After completion of the addition, aging was performed for 120 minutes to obtain a phosphor precursor 22. Thereafter, the phosphor precursor 22 was filtered and dried to obtain a dried phosphor precursor 22. Further, the dried phosphor precursor 22 was baked for 3 hours in a nitrogen atmosphere at 1,050 ° C. to obtain a phosphor 22.

<Manufacture of phosphor 23>
Sodium metasilicate was dissolved in 800 ml of water so that the ion concentration of silicon was 0.4655 mol / l to obtain a solution [A]. Zinc chloride was dissolved in 800 ml of water so that the ion concentration of zinc was 0.8845 mol / l to obtain a solution [B]. Manganese chloride tetrahydrate was dissolved in 200 ml of water so that the manganese ion concentration was 0.1862 mol / l to obtain a solution [C].

  The solution [A] was placed in the container 1 of FIG. 1, and the temperature was maintained at 55 ° C., and stirring was performed using the stirring mechanism 2. In this state, the solution [B] kept at 55 ° C. from the pouring nozzles 3 and 4 of the container 1 containing the solution [A] was kept at 55 ° C. at a rate of 80 ml / min. Was added at a constant rate of 20 ml / min. At this time, a signal from the sensor 6 (in this case, a temperature sensor was used) was fed back to a temperature controller (not shown), and the reaction was performed while controlling at 55 ° C. After completion of the addition, the mixture was heated to 80 ° C. and aged for 120 minutes to obtain phosphor precursor 23. During aging, the signal from the temperature sensor 6 was fed back to a temperature control device (not shown) and controlled to 80 ° C. Thereafter, the phosphor precursor 23 was filtered and dried to obtain a dried phosphor precursor 23. Further, the dried phosphor precursor 23 was baked for 3 hours in a nitrogen atmosphere at 1,050 ° C. to obtain a phosphor 23.

<Manufacture of phosphor 24>
Except that 3% by mass of each of low molecular gelatin (average molecular weight of about 100,000) was added to and dissolved in solution [A], solution [B], and solution [C], fluorescence was obtained in the same manner as the method for manufacturing phosphor 21. Body 24 was obtained.

<Manufacture of phosphor 25>
Except that low molecular gelatin (average molecular weight of about 100,000) was added to the solution [A], the solution [B], and the solution [C] in an amount of 3% by mass, respectively, and the fluorescence was obtained in the same manner as the method for manufacturing the phosphor 22. Body 25 was obtained.

<Manufacture of phosphor 26>
Except that 3% by mass of low molecular gelatin (average molecular weight of about 100,000) was added to each of the solution [A], the solution [B], and the solution [C] and dissolved, fluorescence was obtained in the same manner as the method for manufacturing the phosphor 23. Body 26 was obtained.

As a result of confirming the composition of the obtained phosphors 21 to 26 with a powder X-ray diffractometer, it was Zn ₂ SiO ₄ : Mn ²⁺ . The phosphors (Phosphors 21 to 26) were irradiated with vacuum ultraviolet rays (146 nm), and the emission intensity of each was determined. Next, the relative light emission intensity of each phosphor when the phosphor 8 produced in Example 2 was taken as 100% was calculated. Moreover, the particle diameter was taken with the electron microscope, and the average particle diameter and the variation coefficient were computed. The results are shown in Table 4.

  As is clear from Table 4, it was possible to obtain a phosphor having a small particle size, monodispersion and high emission intensity by generating the phosphor precursor while controlling the temperature.

(Reference example)
<Manufacture of phosphor 27>
Sodium metasilicate was dissolved in 800 ml of water so that the ion concentration of silicon was 0.4655 mol / l to obtain a solution [A]. Zinc chloride was dissolved in 800 ml of water so that the ion concentration of zinc was 0.8845 mol / l to obtain a solution [B]. Manganese chloride tetrahydrate was dissolved in 200 ml of water so that the manganese ion concentration was 0.1862 mol / l to obtain a solution [C].

The solution [A] was placed in the container 1 of FIG. 1 and stirred using the stirring mechanism 2. In this state, the solution [B] was added from the pouring nozzle 3 of the container containing the solution [A]. At this time, a signal from the sensor 6 (in this case using a zinc ion concentration sensor) is fed back to a zinc chloride addition device (not shown) so that the zinc ion concentration becomes 2.2 × 10 ⁻¹ mol / l. The reaction was conducted while controlling so as to be. The solution [C] was added at a constant rate from the pouring nozzle 4 at a rate of 20 ml / min. After completion of the addition, aging was performed for 120 minutes to obtain a phosphor precursor 27. Thereafter, the phosphor precursor 27 was filtered and dried to obtain a dried phosphor precursor 27. Further, the dried phosphor precursor 27 was baked for 3 hours in a nitrogen atmosphere at 1,050 ° C. to obtain a phosphor 27.

<Manufacture of phosphor 28>
A phosphor 28 was obtained in the same manner as the method for producing the phosphor 27 except that the reaction was performed while controlling the zinc ion concentration to be 4.8 × 10 ⁻² mol / l.

<Manufacture of phosphor 29>
Sodium metasilicate was dissolved in 800 ml of water so that the ion concentration of silicon was 0.4655 mol / l to obtain a solution [A]. Zinc chloride was dissolved in 800 ml of water so that the ion concentration of zinc was 0.8845 mol / l to obtain a solution [B]. Manganese chloride tetrahydrate was dissolved in 200 ml of water so that the manganese ion concentration was 0.1862 mol / l to obtain a solution [C].

The solution [A] was placed in the container 1 of FIG. 1 and stirred using the stirring mechanism 2. In this state, the solution [B] was added from the pouring nozzle 3 of the container containing the solution [A]. At this time, a signal from the sensor 6 (in this case using a zinc ion concentration sensor) is fed back to a zinc chloride addition device (not shown) so that the zinc ion concentration becomes 4.8 × 10 ⁻² mol / l. The reaction was conducted while controlling so as to be. Solution [C] was added from the pouring nozzle 4 at a constant rate of 20 ml / min. After completion of the addition, the zinc ion concentration was changed to 1 × 10 ⁻⁵ mol / l and aging was performed for 120 minutes to obtain a phosphor precursor 29. During aging, the signal from the sensor 6 was fed back to a zinc chloride addition device (not shown) and controlled to 6.7 × 10 ⁻⁴ mol / l. Thereafter, the phosphor precursor 29 was filtered and dried to obtain a dried phosphor precursor 29. Further, the dried phosphor precursor 29 was baked for 3 hours in a nitrogen atmosphere at 1,050 ° C. to obtain a phosphor 29.

<Manufacture of phosphor 30>
Fluorescence was performed in the same manner as the method for manufacturing phosphor 27 except that 3% by mass of low molecular gelatin (average molecular weight of about 100,000) was added to each of solution [A], solution [B], and solution [C] and dissolved. A body 30 was obtained.

<Manufacture of phosphor 31>
Except that 3% by mass of low molecular gelatin (average molecular weight of about 100,000) was added to each of the solution [A], the solution [B], and the solution [C] and dissolved, fluorescence was obtained in the same manner as the method for manufacturing the phosphor 28. A body 31 was obtained.

<Manufacture of phosphor 32>
Except that 3% by mass of low molecular gelatin (average molecular weight of about 100,000) was added to each of the solution [A], the solution [B], and the solution [C] and dissolved, fluorescence was obtained in the same manner as the method for manufacturing the phosphor 29. A body 32 was obtained.

The obtained phosphors 27 to 32 were Zn ₂ SiO ₄ : Mn ²⁺ as a result of confirming the composition with a powder X-ray diffractometer. The phosphors (phosphors 27 to 32) were irradiated with vacuum ultraviolet rays (146 nm), and the emission intensity of each was determined. Next, the relative light emission intensity of each phosphor when the phosphor 8 produced in Example 2 was taken as 100% was calculated. Moreover, the particle diameter was taken with the electron microscope, and the average particle diameter and the variation coefficient were computed. The results are shown in Table 5.

  As is clear from Table 5, it was possible to obtain a phosphor having a small particle size, monodispersion and high emission intensity by generating a phosphor precursor while controlling the zinc ion concentration.

It is a conceptual diagram which shows an example of the production | generation apparatus of the fluorescent substance precursor in this invention.

Explanation of symbols

1 Container 2 Stirring mechanism 3, 4, 5 Injection nozzle 6 Sensor

Claims (2)

In a method for producing a phosphor, in which a phosphor precursor is produced in a liquid phase, and then the phosphor precursor is baked to obtain the phosphor.
A method for producing a phosphor, comprising a step of producing a phosphor precursor while performing pH control twice or more in the range from pH 7 to pH 14 from the start to the end of production of the phosphor precursor.   The method for producing a phosphor according to claim 1, wherein the step of generating the phosphor precursor is performed in the presence of a binder.

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