JP2007106831A - Method for producing phosphor and phosphor produced by the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing phosphor fine particles having a narrow particle diameter distribution and further having a high brightness, and the phosphor fine particles produced by the method. <P>SOLUTION: This method for producing the phosphor comprising a precursor-forming process of forming the precursor of the phosphor by a liquid phase method and a baking process of forming the phosphor by baking the precursor is characterized by passing through at least (i) a process of preparing solution containing constituting metal elements of the phosphor in advance, (ii) a process of preparing suspension containing the precursor particles precipitated from the above solution and having ≥0.1 and ≤90% transmittance of the suspension for a visible light having 550 nm wave length, (iii) a process of forming fine droplets of the liquid containing the precursor particles and (iv) a process of introducing the droplets of the liquid containing the precursor particles into a thermally decomposing furnace together with carrier gas and heat-treating. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a phosphor, and more particularly to a method for producing a nano-sized fine particle phosphor.

  Phosphors are materials that convert the energy of excitation rays into light (ultraviolet rays, visible light, infrared rays, etc.) by irradiating excitation rays (ultraviolet rays, visible light, infrared rays, heat rays, electron rays, X-rays, etc.). As commonly used. Examples of the device using the phosphor include a fluorescent lamp, an electron tube, a cold cathode display, a fluorescent display tube, a plasma display panel (hereinafter also referred to as “PDP”), an electroluminescence panel, a scintillation detector, An X-ray image intensifier, a thermofluorescence dosimeter, an imaging plate, etc. are mentioned (for example, refer nonpatent literature 1). Each of these devices is a device that converts electrical energy into excitation ray energy and further converts excitation ray energy into light. An electronic device in which such a device is combined with an electronic circuit or a device component (such as a lighting device, a computer, a keyboard, and an electronic device that does not use a phosphor) is widely used as a lighting device or a display device.

  In addition, as a phosphor-using article using a phosphor, a phosphor in which a powdery phosphor is combined with a substance other than the phosphor, such as a liquid such as water or an organic solvent, a resin, a plastic, a metal, or a ceramic material. These include, for example, liquids and pastes such as phosphor paints, solids such as ashtrays, display materials such as guide plates and guidance articles, seals, stationery, outdoor products, safety signs, etc. Widely used.

  Furthermore, not only the above-mentioned uses but also progress in utilization in the medical field and bio field such as use as a tracer is expected.

  As a method for manufacturing the phosphor, a solid phase method in which a predetermined amount of a compound containing an element constituting the phosphor matrix and a compound containing an activator element are mixed and baked to perform an inter-solid reaction, and a phosphor matrix are constructed. There is a liquid phase method in which a solution containing an element and a solution containing an activator element are mixed to form a precipitate of a phosphor precursor in the solution, and the precursor is solid-liquid separated and then fired.

  In order to increase the yield and luminous efficiency of the phosphor, it is necessary to make the phosphor composition as close to the stoichiometric composition as possible. In the solid-phase method, it is difficult to produce a phosphor having a purely stoichiometric composition. As a result of reaction between solids, excess impurities that do not react and by-products generated by the reaction remain, resulting in stoichiometrically. It is difficult to obtain a high-purity phosphor. Due to the effect that such impurities cannot be burned sufficiently, there are disadvantages such as a decrease in emission intensity, discoloration of the phosphor, uneven firing, etc., and there is a large variation in the emission intensity depending on the firing lot.

  The liquid phase method is more suitable than the solid phase method to obtain a compositionally uniform and high-purity fine particle phosphor.

  When manufacturing a phosphor by a liquid phase method, first, a precipitate which is a precursor of the phosphor is generated and baked to obtain a phosphor. The characteristics of the phosphor such as particle size distribution and emission characteristics are as follows. It depends greatly on the properties of the precursor. Therefore, it is necessary to consider the control of the particle size distribution of the precursor and the exclusion of impurities.

  As a method for improving the particle size distribution of the precursor, a method is known in which a solution or suspension containing a phosphor component is thermally decomposed into droplets (see, for example, Patent Documents 1 and 2). ).

  On the other hand, since II-VI group semiconductor nanoparticles can obtain better light absorption and emission characteristics than the bulk crystal structure, research reports have been actively made in recent years. The excellent optical properties of the semiconductor nanoparticles are thought to be due to the fact that the crystal grain size is as small as nanometers, which increases the band gap and manifests the quantum size effect.

  Here, the nanoparticle means a crystal grain having a particle diameter of about 1 nm to 100 nm, and is generally called a nanocrystal.

In recent years, there have been many reports on ZnS nanoparticles and doped ZnS: Mn ²⁺ nanoparticles produced by using a precipitation technique as an example of nanoparticle phosphors (for example, Patent Documents 3 and 4). reference.). In addition, it has been reported that emission intensity is increased by adding an organic acid such as acrylic acid during a liquid phase reaction utilizing coprecipitation to synthesize a nanoparticle phosphor (Patent Documents 5 and 6). reference.).
JP 2003-261867 A JP 2004-277543 A JP 2002-322468 A JP 2005-239775 A Japanese Patent Laid-Open No. 10-310770 JP 2000-104058 A “Phosphor Handbook” edited by Phosphors Society, Ohmsha, 1987

  Although some of the effects of the method for improving the particle size distribution of precursors disclosed in the above-mentioned patent documents are recognized, they are still not sufficient, and further improvements are required.

  In particular, when trying to reduce the particle size of the phosphor to the nano size for the purpose of high definition, the surface energy of the particles becomes larger and the particles tend to aggregate, so the dispersibility is deteriorated and the particle size distribution is also deteriorated. .

  Accordingly, the present invention has been made in view of the above problems, and an object thereof is to provide a method for producing a fine particle phosphor having a narrow particle size distribution and a high brightness, and a fine particle phosphor produced by the method. To do.

  The above object of the present invention is achieved by the following configurations.

1. In a phosphor manufacturing method comprising a precursor forming step for forming a phosphor precursor by a liquid phase method and a firing step for forming a phosphor by firing the precursor, the phosphor is subjected to at least the following steps. A method for producing a phosphor, comprising: manufacturing a phosphor.
(I) Step of preparing in advance a solution containing the constituent metal elements of the phosphor (ii) A suspension containing precursor particles precipitated from the solution, and for visible light having a wavelength of 550 nm A step of preparing a suspension having a transmittance of 0.1% or more and 90% or less of the suspension (iii) a step of finely forming a liquid containing the precursor particles (iv) the liquid 1. A step of introducing a liquid containing droplets of precursor particles together with a carrier gas into a thermal decomposition reactor and performing a heat treatment. When the suspension containing the precursor particles was allowed to stand for 1 hour, the transmittance change rate after 1 hour of standing was 0.1 relative to the transmittance at the beginning of standing for visible light having a wavelength of 550 nm. The method for producing a phosphor according to claim 1, wherein the phosphor content is from 10% to 10%.

  3. 3. The method for producing a phosphor according to 1 or 2, wherein the phosphor has an average particle size of 100 nm or less.

  4). A phosphor formed by firing phosphor precursor particles, wherein the transmittance of the suspension containing the precursor particles to visible light having a wavelength of 550 nm is 0.1% or more and 90% or less. And when the suspension was allowed to stand for 1 hour, the transmittance change rate after 1 hour of standing was 0.1% or more and 10% with respect to the transmittance at the beginning of standing for visible light having a wavelength of 550 nm. % Or less phosphor.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a fine particle phosphor having a narrow particle size distribution and a high luminance and a method for producing the same.

The phosphor production method of the present invention is a phosphor production method comprising a precursor forming step of forming a phosphor precursor by a liquid phase method, and a firing step of producing the phosphor by firing the precursor. The phosphor is manufactured through at least the following steps.
(I) Step of preparing in advance a solution containing the constituent metal elements of the phosphor (ii) A suspension containing precursor particles precipitated from the solution, and for visible light having a wavelength of 550 nm A step of preparing a suspension in which the transmittance of the suspension is 90% or less (iii) a step of forming liquid droplets containing the precursor particles into fine droplets (iv) a precursor formed into droplets Step of introducing a liquid containing body particles into a pyrolysis reactor together with a carrier gas and heat-treating The present invention and its components will be described in detail below.

  First, a typical method for producing a phosphor by the liquid phase method of the present invention will be described.

  The phosphor basically includes (A) a precursor formation step in which a solution containing a constituent metal element of an inorganic phosphor is mixed to form a precursor of the inorganic phosphor, and (B) a sub-step from the phosphor precursor. A desalting step for removing impurities such as salt, (C) a drying step for drying the precursor obtained by the precursor forming step after the precursor forming step, and (D) a dried precursor after the drying step. And a phosphor forming step of firing to form a phosphor.

  The present invention is characterized by including a firing step of obtaining phosphor particles by drying and heating the precursor obtained in the precursor formation step into droplets. Moreover, you may include the etching process of performing an etching process on the surface of the fluorescent substance particle obtained in the baking process, and removing an impurity.

  Here, the “precursor” of the phosphor according to the present invention is a crystal deposited from a mixed solution in the manufacturing method, and is not subjected to a baking treatment at a high temperature or the like, and is predetermined. It means a crystal in a state that hardly shows the light-emitting property of the wavelength.

  Below, each said process which comprises the manufacturing method of fluorescent substance is demonstrated.

(Precursor formation step)
In the precursor forming step according to the present invention, a precursor is synthesized by a liquid phase method (also referred to as “liquid phase synthesis method”).

  The liquid phase method is a method for producing (synthesizing) a precursor in the presence of a liquid or in a liquid. In the liquid phase method, since the phosphor raw material is reacted in the liquid phase, a reaction between element ions constituting the phosphor is performed, and a stoichiometrically high purity phosphor is easily obtained. Compared with the solid phase method in which the phosphor is produced while repeating the solid phase reaction and the pulverization step, particles having a small particle size can be obtained without performing the pulverization step. It is possible to prevent lattice defects in the crystal and prevent a decrease in light emission efficiency.

  In addition, as the liquid phase method in the present embodiment, a general crystallization method represented by cooling crystallization or a sol-gel method is used, but a reaction crystallization method can be particularly preferably used.

A method for producing a precursor of an inorganic phosphor by a sol-gel method generally includes, for example, Si (OCH ₃ ) ₄ or Eu ³⁺ (CH ₃ COCHCOCH ₃ ) ₃ as a matrix, activator or coactivator. metal alkoxides, Al (OC ₄ H _{9) 3} 2-butanol solution make by adding metal magnesium _{Mg [Al (OC 4 H 9} ) 3] the elemental metal addition to metal complexes or their organic solvent solution of ₂ such as This means a production method by mixing required amounts of double alkoxide, metal halide, metal salt of organic acid or simple metal, and thermally or chemically polycondensing them.

  A method for producing a precursor of an inorganic phosphor by a reaction crystallization method is to use a crystallization phenomenon to mix a solution or source gas containing an element as a phosphor raw material in a liquid phase or a gas phase. This is a method for producing a precursor by the above method. Here, the crystallization phenomenon refers to a change in physical or chemical environment due to cooling, evaporation, pH adjustment, concentration, etc., or a change in the state of the mixed system due to a chemical reaction, etc. In the reaction crystallization method, it means a production method by physical and chemical operations resulting from the occurrence of such a crystallization phenomenon.

  In addition, any solvent can be used as the solvent for applying the reaction crystallization method as long as the reaction raw material is dissolved, but water is preferable from the viewpoint of easy control over the degree of supersaturation. Moreover, when using a some reaction raw material, the order which adds a raw material may be simultaneous or different, and it is possible to select a suitable order suitably according to activity.

  Furthermore, in the formation of the precursor, in order to produce a phosphor with a finer particle size and a narrow particle size range, two or more raw material solutions, including a reaction crystallization method, are placed in a poor solvent in the presence of a protective colloid. It is preferable to add them in the middle. Moreover, it is more preferable to adjust various physical properties such as the temperature during the reaction, the addition rate, the stirring rate, and the pH depending on the type of the phosphor, and ultrasonic waves may be irradiated during the reaction. A surfactant or polymer may be added to control the particle size. It is also a preferred embodiment that the liquid is concentrated and / or aged as necessary after the addition of the raw materials.

  The protective colloid functions to prevent aggregation of the finely divided precursor particles, and various polymer compounds can be used regardless of natural or artificial, and among them, proteins can be preferably used.

  Examples of the protein include gelatin, water-soluble protein, and water-soluble glycoprotein. Specific examples include albumin, ovalbumin, casein, soy protein, synthetic protein, and genetically synthesized protein.

  Examples of gelatin include lime-processed gelatin and acid-processed gelatin, and these may be used in combination. Furthermore, a hydrolyzate of these gelatins and an enzyme degradation product of these gelatins may be used.

  The protective colloid need not have a single composition, and various binders may be mixed. Specifically, for example, a graft polymer of the above gelatin and another polymer can be used.

  The average molecular weight of the protective colloid is preferably 10,000 or more, more preferably 10,000 to 300,000, and particularly preferably 10,000 to 30,000. The protective colloid can be added to one or more of the raw material solutions, and may be added to all of the raw material solutions. Depending on the amount of protective colloid added and the addition rate of the reaction liquid, the particle size of the precursor may be added. Can be controlled.

  In addition, since various properties of the phosphor, such as the particle size, particle size distribution, and emission characteristics of the phosphor particles after firing, are greatly influenced by the properties of the precursor, the particle size control of the precursor is performed in the precursor formation process. It is preferable to make the precursor sufficiently small by performing the above. In addition, when the precursor is microparticulated, aggregation between the precursors is likely to occur, so it is extremely effective to synthesize the precursor after preventing aggregation between the precursors by adding a protective colloid, Particle size control becomes easy. When the reaction is carried out in the presence of a protective colloid, it is necessary to give sufficient consideration to the control of the particle size distribution of the precursor and the exclusion of impurities such as secondary salts.

  In the present invention, the transmittance for visible light having a wavelength of 550 nm of a suspension (including a dispersion) containing a precursor obtained by a liquid phase method is 0.1% or more and 90% or less. It takes a thing. Preferably they are 0.1% or more and 80% or less, More preferably, they are 0.1% or more and 60% or less.

  The transmittance of visible light having a wavelength of 550 nm after standing for 1 hour of the suspension of the precursor has a change rate of 0.1% or more and 10% or less with respect to the initial standing. Preferably they are 0.1% or more and 5% or less, More preferably, they are 0.1% or more and 3% or less.

(Desalting step)
After synthesizing the phosphor precursor in the phosphor precursor forming step, it is preferable to remove impurities such as by-salt from the phosphor precursor by performing a desalting step prior to the drying step and the firing step. Desalting may be performed from the start to the end of precursor formation, or desalting may be performed at the end of precursor formation. Moreover, depending on the reaction degree of a raw material, it may be given for the fixed time in the middle of precursor formation, and may be given several times.

  There is no particular limitation on the desalting method, and any method can be applied. For example, a precipitation desalting method, an electrodialysis method, various membrane separation methods, and a centrifugal separation method are preferably applied, and it is particularly desirable to perform an ultrafiltration treatment.

  As the desalting step, various membrane separation methods, coagulation sedimentation methods, electrodialysis methods, methods using ion exchange resins, Nudelle washing methods, and the like can be applied.

  By conducting the desalting step, the electrical conductivity after desalting of the precursor is preferably in the range of 0.01 to 20 mS / cm, more preferably 0.01 to 10 mS / cm, and particularly preferably 0. 0.01 to 5 mS / cm.

  When the electrical conductivity is less than 0.01 mS / cm, the productivity is lowered. On the other hand, if it exceeds 20 mS / cm, the secondary salt and impurities are not sufficiently removed, so that the coarsening of the particles and the particle size distribution become wide, and the emission intensity deteriorates. Any method can be used as the method for measuring the electrical conductivity, but a commercially available electrical conductivity measuring device may be used. Thereafter, the precursor is recovered by a method such as filtration, evaporation to dryness, and centrifugation.

(Drying and firing process)
The present invention is characterized in that a precursor suspension (including a dispersion) obtained by a liquid phase method is sprayed as fine droplets in a gas atmosphere and dried and heated. At this time, the precursor may be once dried and then sprayed. In the present invention, it is more preferable to spray the precursor suspension after performing wet dispersion treatment.

  As a method of forming a minute droplet, for example, a method of forming a droplet of 1 to 50 μm by spraying a liquid while sucking a liquid with pressurized air, or 4 to 4 using an ultrasonic wave of about 2 MHz from a piezoelectric crystal. A method of forming a 10 μm droplet, a method of vibrating an orifice having a pore diameter of 10 to 20 μm with a vibrator, dropping it at a constant speed, and forming a 20 to 100 μm droplet by centrifugal force, For example, a method of generating a droplet of 0.5 to 10 μm by applying a high voltage can be used.

  The droplets formed by the method as described above are then introduced into a pyrolysis reactor together with a carrier gas, dried and heated to become a phosphor. In order to obtain the type of phosphor and desired characteristics, the type of solvent, the type of carrier gas, the carrier gas flow rate, and the temperature in the pyrolysis reactor can be selected as necessary. For example, the droplet heat treatment step uses a carrier gas such as air, nitrogen, helium, argon or hydrogen, and is heated at an optimum flow rate in the flow path in the pyrolysis reactor. By setting the temperature in the pyrolysis reactor so that the temperature can be controlled, the size / distribution and crystallinity of the fine particles targeted by the present invention can be controlled.

  In the present invention, the solvent is preferably water or a low-boiling organic solvent having a boiling point equal to or lower than water. For example, alcohols such as ethanol and methanol are preferably used. Further, a mixed solvent of water and a low boiling point solvent may be used.

  In the present invention, the gas atmosphere for spraying the precursor-containing droplets is not particularly limited, and may be any of an oxidizing atmosphere, a reducing atmosphere, or an inert atmosphere, and contributes to the type of phosphor main phase and light emission. It selects suitably according to the kind of activator ion. For example, when a phosphor having an oxide as a main phase is synthesized, air, oxygen, nitrogen, hydrogen, nitrogen containing a small amount of hydrogen, or argon is preferable.

On the other hand, when synthesizing a phosphor having sulfide or oxysulfide as the main phase, nitrogen, hydrogen, nitrogen or argon containing a small amount of hydrogen, nitrogen containing hydrogen sulfide or carbon dioxide, hydrogen or argon, etc. are preferable. . Also, when the maintaining valency easily Eu ³⁺ and the like in an oxidizing atmosphere and activating ions, and preferably an oxidizing gas such as air or oxygen, maintaining the valence easily Eu ³⁺ and the like in a reducing atmosphere activator ions In this case, a reducing gas such as hydrogen, nitrogen containing a small amount of hydrogen, or argon is preferable.

  In the present invention, the temperature in the thermal decomposition reactor when spraying the precursor droplets is a temperature within the range of 600 ° C to 1900 ° C. If the temperature is too low, crystallization does not proceed sufficiently, and if the temperature is too high, unnecessary energy is consumed, which is not preferable in terms of cost. The residence time in the furnace is preferably 1 second or more and 24 hours or less. If the residence time is too short, crystallization does not proceed sufficiently, and if the residence time is too long, unnecessary energy is consumed, which is not preferable in terms of cost.

  Moreover, you may add a sintering inhibitor as needed. Of course, it is not necessary to add when there is no need to add. When a sintering inhibitor is added, it may be added as a slurry at the time of precursor formation, or a powdery sintering inhibitor may be added.

The sintering inhibitor 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 baking at 800 ° C. or lower, SiO ₂ is used for baking at 1000 ° C. or lower, and Al ₂ O ₃ is used for baking at 1700 ° C. or lower. Are preferably used. Therefore, in the present invention, it is preferable to use Al ₂ O ₃ .

(surface treatment)
The phosphor produced in the present invention can be subjected to surface treatment such as adsorption and coating for various purposes. The point at which the surface treatment is performed depends on the purpose, and the effect becomes more prominent when appropriately selected. For example, when the surface of the phosphor is coated with an oxide containing at least one element selected from Si, Ti, Al, Zr, Zn, In, and Sn at any point before the dispersion treatment process, The decrease in the crystallinity of the phosphor can be suppressed, and the decrease in the emission intensity can be suppressed by preventing the excitation energy from being captured by the surface defects of the phosphor. Moreover, when the surface of the phosphor is coated with an organic polymer compound or the like at any point after the dispersion treatment step, characteristics such as weather resistance are improved, and a phosphor having excellent durability can be obtained. The thickness and coverage of the coating layer when these surface treatments are performed can be arbitrarily controlled as appropriate.

  The average particle size of the phosphor according to the present invention is preferably 1 nm or more and 100 nm or less. Preferably they are 1 nm or more and 70 nm or less, More preferably, they are 1 nm or more and 50 nm or less. The particle diameter shown here refers to the length of the twill of a particle when the particle is a cubic or octahedral so-called normal crystal. Moreover, when it is not a normal crystal, for example, in the case of a spherical shape, a rod shape, or a flat shape, it means a diameter when a sphere equivalent to the volume of the particle is considered.

  When the average particle size of the phosphor is r and the standard deviation in the particle size distribution is σ, σ / r is 0.5 or less, preferably 0.4 or less, more preferably 0.3 or less.

  In the production method of the present invention, phosphors having various compositions can be produced. Specific examples of the inorganic phosphor according to the present invention are shown below, but the application of the production method of the present invention is not limited thereto.

[Blue light emitting phosphor 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 ) 6Cl ₂ : Eu ²⁺
(BL-8): ZnS: Ag
(BL-9): CaWO ₄
(BL-10): Y ₂ SiO ₅ : Ce
(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 light-emitting phosphor compound]
(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 -2SrCl 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
(GL-19): La ₂ O ₂ S: Tb
(GL-20): Y ₂ SiO ₅ : Ce, Tb
(GL-21): Zn ₂ GeO ₄ : Mn
_{(GL-22): CeMgAl 11} O 19: Tb
(GL-23): SrGa ₂ S ₄ : Eu ²⁺
(GL-24): ZnS: Cu, Co
(GL-25): MgO.nB ₂ O ₃ : Ce, Tb
(GL-26): LaOBr: Tb, Tm
(GL-27): La ₂ O ₂ S: Tb
(GL-28): SrGa ₂ S ₄ : Eu ²⁺ , Tb ³⁺ , Sm ²⁺
[Red-emitting phosphor compound]
(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
(RL-12): YAlO ₃ : Eu ³⁺
(RL-13): YBO ₃ : Eu ³⁺
(RL-14) :( Y, Gd) BO ₃ : Eu ³⁺
The fine particle phosphor according to the present invention, particularly the nano-sized phosphor, can be used for various purposes and applications as described in the “Background Art” section.

  For example, when a fine particle or nanoparticle phosphor of 100 nm or less is used in the form of a coating film, a coating method using an inkjet nozzle can be used. Conventional phosphors with a size of several μm are likely to be clogged with nozzles, and the nozzle diameter needs to be adjusted to the size of the phosphor, which is unsuitable for applying fine patterns. By applying the nanoparticles using an inkjet nozzle having a small nozzle diameter, a fine pattern can be applied.

  Examples of such application applications include the production of fluorescent panels such as PDP / FPD, and the production of fluorescent ink prints (posters, signboards, T-shirts, etc.) using nanoparticles.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to this.

Theoretically, the following six phosphors represented by the composition formula: (Y _0.95 Eu _0.05 ) ₂ O ₃ were prepared.
(Preparation of phosphor 1)
65.5 g of yttrium nitrate (Y (NO ₃ ) ₃ .6H ₂ O) and 4.0 g of europium nitrate (Eu (NO ₃ ) ₃ .6H ₂ O) were dissolved in 500 ml of pure water, respectively. Produced. Next, using a spray pyrolysis apparatus (model: RH-2, manufactured by Okawara Processing Co., Ltd.), C-1 is sprayed on the raw material droplets in an air atmosphere at 900 ° C. and retained for 20 seconds to make phosphor 1 Was made.

(Preparation of phosphor 2)
Add 65.5 g of yttrium nitrate (Y (NO ₃ ) ₃ .6H ₂ O) and 4.0 g of europium nitrate (Eu (NO ₃ ) ₃ .6H ₂ O) to 250 ml of pure water heated to 40 ° C., and stir well. And completely dissolved. This solution is designated as solution A-1. Next, 34.0 g of oxalic acid ((COOH) ₂ .2H ₂ O) was added to 250 ml of pure water heated to 40 ° C., and the mixture was thoroughly stirred to dissolve completely. This solution is designated as solution B-1.

  Subsequently, A-1 liquid and B-1 liquid were simultaneously added in the liquid with the addition rate of 100 ml / min in 500 ml of pure water adjusted to pH 8 with ammonia, and precipitation was produced | generated. At this time, the pH was constantly changing with the addition of the A-1 solution and the B-1 solution, so that ammonia water was simultaneously added to adjust the pH to always be 8 ± 0.5. A total amount of A-1 liquid and B-1 liquid was added, and suspension D-1 containing a precursor was obtained.

  Next, D-1 was sprayed in an air atmosphere at 900 ° C. using a spray pyrolysis apparatus, and was retained for 20 seconds to produce phosphor 2.

(Preparation of phosphor 3)
Add 65.5 g of yttrium nitrate (Y (NO ₃ ) ₃ .6H ₂ O) and 4.0 g of europium nitrate (Eu (NO ₃ ) ₃ .6H ₂ O) to 250 ml of pure water heated to 40 ° C., and stir well. And completely dissolved. This solution was adjusted to pH 8 with ammonia. Let this liquid be A-2 liquid. Next, 34.0 g of oxalic acid ((COOH) ₂ .2H ₂ O) was added to 250 ml of pure water heated to 40 ° C., and the mixture was thoroughly stirred to dissolve completely. This solution is designated as B-2 solution.

  After keeping A-2 liquid and B-2 liquid at 50 degreeC, it supplied with the addition rate used as the Reynolds number 30,000 of a mixing part using the roller pump to the Y-shaped reactor shown in FIG.

  The reaction solution obtained by the reaction was aged while being kept at 50 ° C., and then the reaction solution was circulated at 30 l using Romicon HF 2-20-PM10 (fractionated molecular weight 10,000) as a separation membrane. The suspension containing the precursor is subjected to desalting until the conductivity of the reaction solution becomes 2 mS / m while adding pure water so that the reaction solution volume becomes constant during that time. D-2 was obtained.

  Next, D-2 was sprayed in a nitrogen atmosphere at 1000 ° C. using a spray pyrolysis apparatus, and was retained for 20 seconds to produce phosphor 3.

(Preparation of phosphor 4)
A phosphor 4 was produced in the same manner as the phosphor 3 except that the Reynolds number at the time of precursor generation was changed to 300,000.

(Preparation of phosphor 5)
A phosphor 5 was produced in the same manner as the phosphor 3 except that the Reynolds number at the time of precursor generation was 500,000.

(Preparation of phosphor 6)
The precursor obtained by the production of the phosphor 5 was subjected to solid-liquid separation with a centrifuge and dried at 110 ° C. overnight. The obtained dried precursor was baked at a temperature of 1240 ° C. for 3 hours in an atmosphere of 100% nitrogen to produce phosphor 6.

(Evaluation of phosphor)
Table 1 shows the average particle diameter and monodispersity of the phosphors 1 to 6.

  The average particle diameter and σ / r were taken with a transmission electron microscope (JEOL Ltd., 2000FX type), directly with a magnification of 5000 times, and the negative was captured as a digital image with a scanner, and using appropriate image processing software 300 or more particles were measured, and the average particle size and standard deviation were calculated and determined.

  A method for evaluating the phosphor will be described.

  Relative emission intensity is determined by irradiating each phosphor powder with vacuum ultraviolet rays using an excimer 146 nm lamp (USHIO Inc.) in a vacuum chamber of 0.1 to 1.5 Pa, and detecting the obtained green light. The relative light emission intensity, which is a relative value when the light emission intensity of the phosphor powder 1 is set to 100, is measured using a vessel (MCPD-3000: manufactured by Otsuka Electronics Co., Ltd.). It was shown in 1.

  As is clear from Table 1, it can be seen that the phosphor according to the method for producing the phosphor of the example of the present invention is a fine particle phosphor having a narrow particle size distribution and high brightness.

Y-shaped reactor

Explanation of symbols

A phosphor raw material solution B phosphor raw material solution M mixer P roller pump

Claims (4)

In a phosphor manufacturing method comprising a precursor forming step of forming a phosphor precursor by a liquid phase method and a firing step of forming the phosphor by firing the precursor, the phosphor is subjected to at least the following steps. A method for producing a phosphor, comprising: manufacturing a phosphor.
(I) Step of preparing in advance a solution containing a constituent metal element of the phosphor (ii) A suspension containing precursor particles precipitated from the solution, and for visible light having a wavelength of 550 nm (Iii) a step of finely forming a liquid containing the precursor particles (iv) the liquid A step of introducing a liquid containing droplets of precursor particles together with a carrier gas into a thermal decomposition reactor and performing a heat treatment When the suspension containing the precursor particles was allowed to stand for 1 hour, the transmittance change rate after 1 hour of standing was 0.1 relative to the transmittance at the beginning of standing for visible light having a wavelength of 550 nm. The method for producing a phosphor according to claim 1, wherein the phosphor content is from 10% to 10%. The method for producing a phosphor according to claim 1 or 2, wherein the phosphor has an average particle size of 100 nm or less. A phosphor formed by firing phosphor precursor particles, wherein the transmittance of the suspension containing the precursor particles to visible light having a wavelength of 550 nm is 0.1% or more and 90% or less. And when the suspension was allowed to stand for 1 hour, the transmittance change rate after 1 hour of standing was 0.1% or more and 10% with respect to the transmittance at the beginning of standing for visible light having a wavelength of 550 nm. % Or less phosphor.

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