JP2006077079A - Preparation process of phosphor, phosphor and primer display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the light emitting efficiency of both a phosphor and a plasma display panel. <P>SOLUTION: In the preparation process of the phosphor comprising the step of forming a precursor of the phosphor by a liquid phase method, desalination is carried out during the period from the start of a precursor formation to the end or immediately after the formation. The desalinated precursor is treated by calcination in an oxygen containing atmosphere under specific conditions and further the above treated precursor is again treated by calcination in a weakly reductive atmosphere. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a phosphor manufacturing method, a phosphor, and a plasma display panel, and more particularly, to a phosphor manufacturing method, a phosphor, and a plasma display panel that include a desalting step and a plurality of heating steps under a predetermined condition. .

  In recent years, as a display device using a new video display method replacing CRT (Cathode Ray Tube), a liquid crystal display (LCD) using a liquid crystal panel and an electroluminescence (EL) phenomenon are used. Plasma displays using an EL display and a plasma display panel (hereinafter referred to as “PDP”) have been developed.

  Among them, the plasma display can be reduced in thickness and weight, the structure can be simplified and the screen can be enlarged, and the visible range, so-called viewing angle, can reach 160 degrees or more in both the horizontal and vertical directions. Compared with a liquid crystal panel, it is also possible to see clear images from a wide range of up, down, left and right. In addition, since it is a video display method with fixed pixels using a dot matrix, it is possible to suppress occurrence of color misalignment and screen distortion, and to display a high-quality video even on a large screen.

  PDPs used in these plasma displays are provided with a number of discharge cells formed by two glass substrates provided with electrodes and barrier ribs provided between the substrates. Inside these discharge cells are phosphors. A phosphor layer coated with is formed. The PDP configured in this manner selectively discharges the discharge cell by applying a voltage between the electrodes, thereby causing vacuum ultraviolet rays (hereinafter referred to as VUV: Vacuum Ultraviolet) caused by the discharge gas enclosed in the discharge cell. ) And the phosphor is excited by this VUV to emit visible light.

  As a general method for producing the above phosphor, a solid phase method in which a compound containing an element constituting the phosphor matrix and a compound containing an activator element are mixed in a predetermined amount and then baked to perform a solid-solid reaction, A liquid phase method in which a phosphor raw material solution containing an element constituting the phosphor matrix and a phosphor raw material solution containing an activator element are mixed, and the obtained phosphor precursor precipitate is solid-liquid separated and then fired. There is.

  Among these production methods, in the solid phase method, as a result of the reaction between solids, surplus impurities that do not react and by-products generated by the reaction remain, so that a stoichiometrically high purity phosphor is obtained. Therefore, there has been a problem that the yield and luminous efficiency of the obtained phosphor are reduced. In addition, since it is difficult to reduce the diameter of the phosphor particles due to the reaction between solids, it is difficult to increase the specific surface area and improve the emission intensity. The liquid phase method is preferably used.

  On the other hand, the phosphor particles obtained by the liquid phase method are extremely small, and it is difficult to perform each treatment such as washing or solid-liquid separation, so that it is difficult to control the particle size and particle size distribution. The remaining impurities, sub-salts, and the like present in the precursor precipitation medium cause problems such as discoloration of the phosphor, uneven firing, and damage to the phosphor body due to sputtering or VUV irradiation.

  Therefore, as a phosphor capable of improving the emission intensity and a production method thereof, in a phosphor production method by a liquid phase method, by including a desalting step from the start to the end of precursor formation, A phosphor manufacturing method has been developed that removes excess impurities that do not react and by-products generated by the reaction (see, for example, Patent Document 1).

Further, as a method for producing a phosphor capable of improving the production stability and emission intensity, in the method for producing a phosphor by a liquid phase method, a step of heating the precursor of the phosphor in an oxygen atmosphere, and heating A phosphor that burns impurities, sub-salts, and the like remaining in the phosphor raw material mixture before firing by providing a step of heating the precursor of the subsequent phosphor in a weakly reducing atmosphere. Has been developed (see, for example, Patent Document 2).
JP 2003-171661 A JP 2003-183643 A

  However, in the phosphor manufacturing method described above, impurities, sub-salts, and the like are not sufficiently removed and burned, thereby preventing discoloration of the phosphor, burning unevenness, and damage to the phosphor body due to sputtering or VUV irradiation. As a result, a sufficient effect cannot be obtained, resulting in a problem that the emission intensity is lowered.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a phosphor manufacturing method, a phosphor, and a plasma display panel capable of improving the emission intensity.

In order to solve the above problems, a method for manufacturing a phosphor according to the invention described in claim 1 comprises:
In a method for producing a phosphor that forms a phosphor precursor by a liquid phase method,
A desalting step of performing a desalting treatment between the start and end of formation of the precursor or immediately after the end;
A first firing step of performing a firing treatment under predetermined conditions in an oxygen-containing atmosphere on the precursor after the desalting treatment;
And a second baking step of performing a baking process under a predetermined condition in a weakly reducing atmosphere on the precursor after the baking process.

  According to the first aspect of the present invention, in the phosphor manufacturing method for forming the phosphor precursor by the liquid phase method, the desalting treatment is performed during the period from the start to the end of the precursor formation or immediately after the end. A salt process, a first firing process in which a precursor after desalting is fired under a predetermined condition in an oxygen-containing atmosphere, and a precursor in a weakly reducing atmosphere after firing. A second baking step for performing a baking process under the above conditions, and after removing impurities or by-salts present in the phosphor raw material mixture by a desalting process, a baking process is further performed under a predetermined condition. Thus, even if impurities or subsalts remain in the phosphor raw material mixture after the desalting treatment, the impurities or subsalts can be reliably burned.

  The method for producing a phosphor according to claim 2 is characterized in that the electrical conductivity at the end of the precursor formation is 0.01 to 20 mS / cm.

  According to the invention described in claim 2, since the electrical conductivity at the end of the precursor formation is 0.01 to 20 mS / cm, the phosphor can be obtained by adjusting the electrical conductivity at the end of the precursor formation. The amount of impurities and by-salts in the raw material mixture can be controlled.

  According to a third aspect of the present invention, there is provided a method for producing a phosphor, wherein a firing temperature in the first firing step is 1000 to 1400 ° C.

  According to invention of Claim 3, since the calcination temperature of the said 1st baking process is 1000-1400 degreeC, the phosphor raw material after a desalination process is adjusted by adjusting the calcination temperature of a 1st baking process. Even when impurities or by-salts or the like are mixed in the mixture, impurities or by-salts can be more reliably burned.

  According to a fourth aspect of the present invention, there is provided a method for producing a phosphor, wherein the firing time of the first firing step is 2 to 6 hours.

  According to the invention described in claim 4, since the firing time of the first firing step is 2 to 6 hours, the phosphor raw material after the desalting treatment is adjusted by adjusting the firing time of the first firing step. Even when impurities or by-salts or the like are mixed in the mixture, impurities or by-salts can be more reliably burned.

  The phosphor manufacturing method according to the invention described in claim 5 is characterized in that the firing temperature in the second firing step is 800 to 1400 ° C.

  According to invention of Claim 5, since the calcination temperature of the said 2nd baking process is 800-1400 degreeC, the phosphor raw material after a desalination process is adjusted by adjusting the calcination temperature of a 2nd baking process. Even when impurities or by-salts or the like are mixed in the mixture, impurities or by-salts can be more reliably burned.

  The phosphor manufacturing method according to the invention of claim 6 is characterized in that the firing time of the second firing step is 2 to 6 hours.

  According to the invention described in claim 6, since the firing time of the second firing step is 2 to 6 hours, the phosphor raw material after the desalting treatment is adjusted by adjusting the firing time of the second firing step. Even when impurities or by-salts are mixed in the mixture, impurities or by-salts can be burned more reliably.

  A phosphor according to a seventh aspect of the invention is manufactured by the manufacturing method according to any one of the first to sixth aspects.

  According to the invention described in claim 7, since it is manufactured by the manufacturing method according to any one of claims 1 to 6, impurities or by-salts are reliably removed in the manufacturing process. Therefore, the stoichiometric purity can be improved.

  A plasma display panel according to an eighth aspect of the invention includes a discharge cell manufactured using the phosphor according to the seventh aspect.

  According to the eighth aspect of the present invention, since the discharge cell manufactured using the phosphor according to the seventh aspect is provided, the emission intensity of the discharge cell can be improved.

  According to the first aspect of the present invention, in the phosphor manufacturing method for forming the phosphor precursor by the liquid phase method, the desalting treatment is performed during the period from the start to the end of the precursor formation or immediately after the end. A salt process, a first firing process in which a precursor after desalting is fired under a predetermined condition in an oxygen-containing atmosphere, and a precursor in a weakly reducing atmosphere after firing. And a second firing step for performing the firing treatment under the conditions described above, by removing impurities or by-salts present in the phosphor raw material mixture by the desalting treatment and further heating under predetermined conditions Even when impurities or by-salts remain in the phosphor raw material mixture after the desalting treatment, it is possible to surely burn the impurities or by-salts, thereby enabling the subsequent firing step. Phosphor discoloration in Damage to the phosphor body by irradiation of adult village and sputtering or VUV can be prevented.

  According to the invention described in claim 2, since the electrical conductivity at the end of the precursor formation is 0.01 to 20 mS / cm, the phosphor can be obtained by adjusting the electrical conductivity at the end of the precursor formation. It becomes possible to control the amount of impurities and sub-salts in the mixture of raw materials, whereby a more preferable effect can be obtained.

  According to invention of Claim 3, since the calcination temperature of the said 1st baking process is 1000-1400 degreeC, Since the calcination temperature of the said 1st baking process is 1000-1400 degreeC, it is 1st baking. By adjusting the firing temperature of the process, even when impurities or subsalts are mixed in the phosphor raw material mixture after the desalting treatment, impurities or subsalts can be burned more reliably. Therefore, a more preferable effect can be obtained.

  According to the invention described in claim 4, since the firing time of the first firing step is 2 to 6 hours, the phosphor raw material after the desalting treatment is adjusted by adjusting the firing time of the first firing step. Even when impurities or by-salts are mixed in this mixture, impurities or by-salts can be more reliably burned, and thereby more favorable effects can be obtained.

  According to invention of Claim 5, since the calcination temperature of the said 2nd baking process is 800-1400 degreeC, the phosphor raw material after a desalination process is adjusted by adjusting the calcination temperature of a 2nd baking process. Even when impurities or by-salts are mixed in this mixture, impurities or by-salts can be more reliably burned, and thereby more favorable effects can be obtained.

  According to the invention described in claim 6, since the firing time of the second firing step is 2 to 6 hours, the phosphor raw material after the desalting treatment is adjusted by adjusting the firing time of the second firing step. Even when impurities or by-salts are mixed in this mixture, impurities or by-salts can be more reliably burned, and thereby more favorable effects can be obtained.

  According to the invention described in claim 7, since it is manufactured by the manufacturing method according to any one of claims 1 to 6, by removing impurities or by-salts in the manufacturing process, It becomes possible to improve the stoichiometric purity, thereby improving the emission intensity of the phosphor.

  According to the eighth aspect of the present invention, since the discharge cell manufactured using the phosphor according to the seventh aspect is provided, the emission intensity of the discharge cell can be improved. The emission intensity can be improved.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, although various technically preferable limitations for implementing the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples.

Details of the phosphor manufacturing method, the phosphor and the plasma display panel according to the present invention will be described with reference to FIGS.
First, the phosphor according to the present invention will be described.
The phosphor according to the present invention is a vacuum ultraviolet-excited phosphor (hereinafter referred to as “phosphor”) that is particularly susceptible to light emission intensity due to the composition in the vicinity of the surface layer. After the treatment, it is fired under a predetermined condition in an oxygen atmosphere, and further fired under a predetermined condition in a weakly reducing atmosphere. Even when the by-salt etc. remains, the impurities or by-salt etc. are uniformly and reliably burned, the impurities or by-salt etc. are removed, and the phosphor efficiently receives VUV, The emission intensity is improved. More specifically, the phosphor particles that have been desalted are manufactured by a liquid phase method, and the electrical conductivity at the end of precursor formation is preferably 0.01 to 20 mS / cm. .

  The electrical conductivity at the end of the formation of the phosphor precursor according to the present invention is more preferably 0.01 to 10 mS / cm, and particularly preferably 0.01 to 5 mS / cm. If it is 0.01 mS / cm or less, the effect is not particularly increased, and the productivity is lowered. This is because the effect of the present invention is not exhibited because impurities and sub-salts are not sufficiently removed at 20 mS / cm or more.

  Moreover, a conventionally well-known method is applicable to the measuring method of electrical conductivity, For example, a commercially available electrical conductivity measuring device can be used.

Specific examples of the inorganic phosphor used as the phosphor according to the present invention are shown below.
[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 ) ₆ Cl 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⁺

Incidentally, the phosphor according to the present invention, the _{(GL-14) Zn 2 SiO} 4: Application of Mn ²⁺ are preferred.

Next, a method for manufacturing the above-described phosphor will be described.
The phosphor manufacturing method according to the present invention includes a precursor forming step for forming a phosphor precursor, a firing step for firing the precursor obtained in the precursor forming step to obtain phosphor particles, and a firing step. And a surface treatment process for removing impurities and the like by performing an etching process on the surface of the phosphor particles obtained in (1).

First, the precursor forming step will be described.
In the precursor forming step, a precursor that is an intermediate product of the phosphor is synthesized by a liquid phase method, and in the subsequent firing step, the precursor is fired at a predetermined temperature, thereby obtaining phosphor particles. it can.

  The liquid phase method is a method for synthesizing a precursor in the presence of a liquid or in a liquid, and is also called a liquid phase synthesis method. 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 a phosphor is produced while repeatedly performing a reaction between solid phases and a pulverization step, it is possible to obtain particles having a small particle size without performing a pulverization step. Lattice defects in the crystal due to such stress can be prevented, and reduction in light emission efficiency can be prevented.

  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 is a change from the liquid phase to the solid phase when the physical or chemical environment changes due to cooling, evaporation, pH adjustment, concentration, or when the state of the mixed system changes due to a chemical reaction. 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.

  Further, in the formation of the precursor, in order to produce a phosphor with a finer particle size distribution and narrower, a raw material solution of two or more liquids including a reaction crystallization method is liquid in a poor solvent in the presence of a protective colloid. It is preferable to add them in the middle.

  In the reaction crystallization method in the present embodiment, as shown in FIG. 1, a so-called Y-shaped reaction apparatus 1 is used in which the shape of the plurality of flow paths provided is Y-shaped in plan view. Among these, the Y-shaped reactor 1 includes a first tank 2 in which one phosphor raw material solution A is stored and a second tank 3 in which another phosphor raw material solution B is stored. The first tank 2 and the second tank 3 are connected to one end of the first flow path 4 and the second flow path 5, respectively. Pumps P1 and P2 for supplying the phosphor raw material solutions A and B are provided in the middle of the first flow path 4 and the second flow path 5, respectively. Further, the other ends of the flow paths 4 and 5 are connected to the third flow path 6 via the connection portion C, and are continuously supplied via the flow paths 4 and 5 at the connection portion C. The phosphor raw material solutions A and B are collided and mixed.

  The third flow path 6 is configured to continuously supply the mixed solution after mixing to the aging container 7 installed below the discharge port of the third flow path 6. The flow rate of the mixed solution is larger than the flow rate of each solution supplied by the second flow path 5.

  The aging container 7 is provided with a stirring blade 8 for stirring the mixed solution stored therein, and this stirring blade 8 is connected to a driving device 9 which is a rotational power source.

  An ultrafiltration device 10 is provided at a position adjacent to the Y-shaped reactor 1 for separating impurities, sub-salts and the like in the mixed solution. In the ultrafiltration device 10, one end of a suction tube 11 for introducing the mixed solution stored in the aging container 7 into the ultrafiltration device 10 and the filtered mixed solution into the aging container 7 again. One end of the discharge pipe 12 for introduction is connected, and the other ends of the suction pipe 11 and the discharge pipe 12 are arranged at arbitrary positions in the internal space of the aging container 7.

  The manufacturing apparatus used is not limited to the Y-shaped reactor 1, and may be a so-called T-shaped manufacturing apparatus that differs only in the form of the flow path and is T-shaped in plan view.

  The first, second, and third flow paths 4, 5, and 6 are formed in a cylindrical shape, and the diameter of each flow path 4, 5, and 6 is formed to be about 1 mm.

  Note that the diameter and length of the third flow path 6 are not limited to the present embodiment, and the time until the particles immediately formed by the collision mixing in the connecting portion C become substantially stable, the so-called stable time. As long as it is possible to satisfy the above, any diameter size and length may be used. Here, the stabilization time in this embodiment is set to 0.001 seconds or more.

  In addition, the so-called moving time during which the Y-shaped reactor 1 stays while moving, that is, the moving time is preferably 0.001 seconds or more, more preferably 0.01 seconds or more, and particularly preferably 0.1 seconds or more.

  Furthermore, any pump can be applied as long as the pumps P1 and P2 are conventionally known pumps, but a pulsation pump is preferable.

  Furthermore, although the connection part C is not equipped with the dynamic stirring mechanism, it is not limited to this embodiment, According to the objective, you may be equipped with dynamic stirring mechanisms, such as a stirring blade.

  Further, when the phosphor raw material solutions A and B are supplied through the first flow path 2 and the second flow path 3, the back flow around the connection portion C is prevented and more uniform mixing is performed. In addition, it is preferable that the flow is substantially turbulent.

  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. In addition, a surfactant or a polymer may be added for particle size control. Furthermore, after adding a raw material, you may perform only one of concentration and aging of a solution, or concentration or aging as needed.

  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 does not need to 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. Therefore, it is extremely effective to synthesize the precursor while 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 precursor process described above, a desalting process is performed for a certain period of time between the start and end of precursor formation. This desalting step is a step for removing impurities such as by-salts from the precursor, and various membrane separation methods, coagulation sedimentation methods, electrodialysis methods, methods using ion exchange resins, nudelle washing methods, etc. can be applied. However, it is preferably carried out by a method using an ultrafiltration membrane.

  In addition, the time of a desalting process is not limited to this embodiment, You may perform immediately after completion | finish of precursor formation. Moreover, it may be performed a plurality of times depending on the reaction conditions of the raw materials.

  Furthermore, after the desalting step, a drying step may be further performed. The drying step is preferably performed after the desalting step, and any method such as vacuum drying, airflow drying, fluidized bed drying, spray drying, and the like can be applied. The drying temperature is not particularly limited, but is preferably a temperature near or above the temperature at which the solvent used is vaporized. If the drying temperature is too high, baking is performed simultaneously with drying, and subsequent baking treatment is performed. Since the phosphor can be obtained without any problem, it is more preferably 50 to 300 ° C.

Next, the firing process will be described.
The rare earth borate phosphor, silicate phosphor, aluminate phosphor and the like used in the present embodiment are obtained by firing each precursor in the firing step. In this invention, this baking process is divided into a 1st baking process and a 2nd baking process, and demonstrates the conditions of a 1st and 2nd baking process, respectively.

  In the first firing step, the precursor is fired in an atmosphere containing oxygen. In addition, it is preferable that oxygen concentration is 1 to 50%, and, as for the atmosphere at this time, it is more preferable that it is 10 to 30%.

  The firing temperature in the first firing step is preferably 1000 to 1400 ° C, more preferably 1100 to 1300 ° C. Furthermore, the firing time is preferably 2 to 6 hours, more preferably 2 to 4 hours.

On the other hand, in the second firing step, a firing process is performed on the heated phosphor in a weakly reducing atmosphere. The atmosphere at this time preferably has an oxygen concentration of 100 ppm or less, and more preferably 10 ppm or less.
As described above, the atmosphere in the second firing step is preferably as the oxygen concentration is small. However, in the case where oxygen is not present, the mixed gas is a hydrogen concentration of 0.1 to 10% and the remaining components are all nitrogen. A mixed gas in which the hydrogen concentration is 0.1 to 5% and the remaining components are all nitrogen is more preferable.

  Furthermore, the firing temperature in the second firing step is preferably 800 to 1400 ° C, more preferably 900 to 1200 ° C. Furthermore, the firing time is preferably 2 to 6 hours, more preferably 2 to 4 hours.

  Conventionally known apparatuses or containers can be applied to the baking apparatus or baking container, and apparatuses such as a box furnace, a crucible furnace, a cylindrical tube type, a boat type, and a rotary kiln are preferably used.

  Moreover, a sintering inhibitor may be added as needed at the time of baking. In the case of adding a sintering inhibitor, it may be added as a slurry at the time of forming the precursor, or may be fired by mixing a powdery sintering inhibitor with the dried precursor.

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 firing at 800 ° C. or lower, SiO ₂ is used for firing at 1000 ° C. or lower, and Al ₂ O is used for firing at 1700 ° C. or lower. ₃ are each preferably used.

  In addition, after each baking process, a reduction process or an oxidation process etc. may be performed as needed. Moreover, a cooling process, a surface treatment, a dispersion process, etc. may be performed after a 2nd baking process, and a classification process may be performed.

  The cooling process is a process of cooling the fired product obtained in the firing process, and it is possible to cool the fired product while filling the fired device. The cooling treatment is not particularly limited, and can be appropriately selected from conventionally known cooling methods such as a method of lowering the temperature by leaving alone or a method of forcibly lowering the temperature while controlling the temperature using a cooler. is there.

  The surface treatment is a treatment for adsorbing or coating the surface of the fired product obtained in the firing step. The point at which the surface treatment is performed varies depending on the purpose and can be selected as appropriate. 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 subsequent dispersion treatment, A decrease in crystallinity of the phosphor during processing can be suppressed, and further, a decrease in emission intensity can be suppressed by preventing excitation energy from being captured by 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. In addition, the thickness of the coating layer, the coverage, and the like when performing these surface treatments can be arbitrarily controlled as appropriate.

  The dispersion treatment is a treatment for atomizing the fired product obtained in the firing step, such as a high-speed stirring impeller-type disperser, a colloid mill, a roller mill, or a ball mill, a vibrating ball mill, an attritor mill, a planetary ball mill, a sand mill, etc. Uses a device that moves media media in the device and atomizes both by collision and shear force, or a dry type disperser such as a cutter mill, hammer mill, jet mill, ultrasonic disperser, high pressure homogenizer, etc. It is done.

  Among these, in the present invention, it is particularly preferable to use a wet media type disperser that uses a medium that is a medium, and it is more preferable to use a continuous wet media type disperser that can be continuously dispersed. Moreover, the aspect etc. which connect a some continuous type and a wet media type | mold disperser in series are applicable.

  Here, “continuous dispersion processing is possible” means that at least the phosphor and the dispersion medium are dispersed in a constant quantity ratio per hour while being supplied to the disperser, and at the same time, manufactured in the disperser. It means a form in which the dispersion is discharged from the disperser without being interrupted in the form of being pushed out to supply. In the case of using a wet media type disperser that uses a medium as a medium for the dispersion process in the phosphor manufacturing method, the dispersion chamber container, so-called vessel, can be appropriately selected from a vertical type and a horizontal type.

Finally, the surface treatment process will be described.
Since the phosphor according to the present invention does not have the role of improving the light emission intensity by the convex portion on the surface unlike the electroluminescent phosphor, the viewpoint that the phosphor particles are densely packed in the phosphor layer and the fluorescence From the viewpoint of uniformly etching the surface of the body particles, it is preferable to perform etching on the phosphor particles with few or no projections on the particle surface. Is performed by an etching process.

  In addition, it is possible to select appropriately according to impurities on the surface of the phosphor particles. For example, a physical method of scraping the surface by fine particles or ion sputtering may be used. A chemical method such as soaking body particles to dissolve surface impurities and the like is effective. At this time, if the etching solution erodes the phosphor particle main body, the emission intensity becomes low, so that the etching needs to be performed carefully.

  The above-described Y-shaped reactor 1 can be applied to the etching process, but is not limited to the Y-shaped reactor 1, and may be a general reactor 21 as shown in FIG. As shown in FIG. 3, a double jet reactor 31 using a double jet method in which two kinds of reaction solutions are simultaneously added to mother liquor with separate nozzles may be used.

  The reaction apparatus 21 shown in FIG. 2 includes a tank 22, and the etching solution stored in the tank 22 is dispersed in the phosphor stored in the reaction container 24 via the flow path 23 by the pump P 3. It is added to the solution. Further, similarly to the Y-shaped reactor 1 described above, a stirring blade 26 connected to the driving device 25 is provided to stir the mixed solution.

  3 includes a first tank 32 and a second tank 33. The first tank 32 and the second tank 33 include a first flow path 34 and a second tank 33, respectively. One end of the second flow path 35 is connected to each other. In addition, pumps P4 and P5 are provided in the middle of the first flow path 34 and the second flow path 35, respectively.

  The other ends of the first flow path 34 and the second flow path 35 are respectively connected to the reaction vessel 36 so that the solutions stored in the first tank 32 and the second tank 33 are supplied. In addition, the reaction vessel 36 is provided with a stirring blade 38 connected to a driving device 37 so as to stir the mixed solution.

  The stirring time is preferably 5 minutes or more and less than 2 hours, and more preferably 20 minutes or more and less than 1 hour after the addition of the acid is completed. This is because the emission intensity decreases if the range is out of this range.

  Furthermore, the addition amount of the etching solution is preferably 0.001 to 0.005 mol, more preferably about 0.002 mol, per 1 g of the phosphor.

Further, the addition rate of the etching solution is preferably 1.2 × 10 ^{−16 to} 7.0 × 10 ⁻¹⁵ mol / min per 1 m ² of the specific surface area of the phosphor, and 2.0 × 10 ^{−16 to} 5 More preferably, it is 0.0 × 10 ⁻¹⁵ mol / min.

  Furthermore, it is preferable that the temperature of an etching liquid is 20-60 degreeC, and it is more preferable that it is 30-50 degreeC.

  Furthermore, the type of the etching solution is determined according to impurities and the like, and may be acidic or alkaline, or an aqueous solution or an organic solvent. At this time, when an acidic aqueous solution is used, the effect appears remarkably, so that a strong acid is particularly preferably used.

  As the strong acid, hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, perchloric acid and the like are applicable, but hydrochloric acid, nitric acid and sulfuric acid are preferable, and hydrochloric acid is particularly preferable.

  As the concentration of the strong acid increases, the concentration of the eluted substance increases, and the substance removed during the etching process may be re-adsorbed on the particle surface, and the amount of the surface layer of the phosphor particles to be removed increases. Therefore, industrial efficiency falls. In addition, concentration localization is likely to occur during etching, making it difficult to uniformly perform etching between particles, and the effect on the emission intensity is reduced.

  On the other hand, when the concentration of the strong acid is reduced, the amount of impurities and the like on the surface of the phosphor particles is reduced, and the impurities and the like remain on the surface of the particles. As a result, the effect on the emission intensity is reduced.

  In addition, since the amount of strong acid required for the etching treatment for the phosphor particles increases, it becomes difficult to handle industrially. Therefore, it is desirable to adjust the concentration of the strong acid to the most preferable value depending on the situation.

  When these strong acids are used in the etching solution, the concentration of the etching solution is preferably 0.001 N or more and less than 6 N, more preferably 0.001 N or more and less than 2.5 N, and more preferably 0.001 N or more and 0. Particularly preferred is less than .25N. A desired effect can be obtained by performing etching using a strong acid of 0.001N or more and less than 6N. In particular, when a strong acid of 0.001N or more and less than 0.25N is used, only impurities are efficiently dissolved. The concentration of the eluted substance is low, and it becomes difficult to re-adsorb the removed substance on the particle surface. Further, during etching, the concentration of strong acid can be suppressed, and the particle surface can be uniformly etched.

For example, when etching is performed on Zn ₂ SiO ₄ : Mn ²⁺ using hydrochloric acid, Zn ₂ SiO ₄ is dissolved in hydrochloric acid according to the following reaction formula, and the surface layer of the phosphor particles is removed. .
Zn ₂ SiO ₄ + 4HCl → 2ZnCl ₂ + SiO ₂ + 2H ₂ O

From the above reaction formula, it is possible to control the amount of dissolved Zn ₂ SiO ₄ , that is, the amount removed by etching treatment, by changing the amount of strong acid reacted per unit mole of the phosphor. I understand. For example, when 2% of 1 mol of phosphor particles is desired to be dissolved, that is, when it is desired to be removed by etching, it may be reacted with 0.08 mol of hydrochloric acid.

  In addition, it is preferable that the quantity which dissolves and removes the surface of a fluorescent substance particle by an etching process is 1.5 mol% or more and less than 20 mol% of a fluorescent substance particle. In addition, after etching, it is preferable to perform a water washing process or the like to remove the etching solution.

  As described above, the phosphor manufacturing method according to the present invention is a desalting treatment between the start of formation of the precursor and the end thereof or immediately after the end in the phosphor manufacturing method of forming the phosphor precursor by the liquid phase method. A desalting step in which the precursor after the desalting treatment is subjected to a firing treatment at a constant temperature in an oxygen-containing atmosphere, and a weakly reducing atmosphere is applied to the precursor after the firing treatment. A second baking step of performing a baking process at a constant temperature, and after removing impurities or sub-salts present in the phosphor raw material mixture by a desalting process, further performing a baking process under predetermined conditions Thus, even if impurities or by-salt remains in the phosphor raw material mixture after the desalting treatment, it is possible to reliably burn out the impurities or by-salt, and thereby discolor the phosphor. And firing unevenness and Ttaringu or it is possible to prevent damage to the phosphor body by irradiation of VUV.

  In addition, the phosphor produced by the method for producing a phosphor according to the present invention can improve the stoichiometric purity by removing impurities, sub-salts, etc. during the production process. Thus, the emission intensity of the phosphor can be improved.

Finally, a PDP using the above-described phosphor will be described.
In general, PDPs are roughly classified into a DC type that applies a DC voltage and an AC type that applies an AC voltage depending on the electrode structure and operation mode. In this embodiment, as shown in FIG. Details will be described below with reference to an AC type PDP.

  As shown in FIG. 4, the PDP 101 in the present embodiment has a front plate 102 formed into a flat plate shape, and a back plate that is substantially the same shape as the front plate 102 and is disposed at a position facing one surface of the front plate 102. And a face plate 103. Of these substrates 102 and 103, the front plate 102 transmits visible light emitted from the discharge cells and displays various information on the substrate, and functions as a display screen of the PDP 101.

  The front plate 102 is preferably made of a material that transmits visible light, such as soda lime glass, so-called blue plate glass, and the thickness is preferably in the range of 1 to 8 mm, and more preferably 2 mm.

  Further, on the front plate 102, a plurality of display electrodes 104 are arranged at regular intervals on the surface of the front plate 102 facing the back plate 103. These display electrodes 104 include a transparent electrode 105 formed in a wide band shape and a bus electrode 106 formed in the same shape as the transparent electrode 105, and the bus electrode 106 is laminated on the upper surface of the transparent electrode 105. It has a structure.

  The display electrode 104 is orthogonal to the partition wall 112 in a plan view, and is a set of two arranged in a positional relationship facing each other with a predetermined discharge gap.

  A transparent electrode such as a nesa film is applicable as the transparent electrode 105, and the sheet resistance is preferably 100Ω or less. The width dimension of the transparent electrode 5 is preferably in the range of 10 to 200 μm.

  The bus electrode 106 is for lowering the resistance, and is formed by sputtering of Cr / Cu / Cr or the like. Moreover, the width dimension of the bus electrode 106 is formed smaller than the transparent electrode 105, and the range of 5-50 micrometers is preferable.

  The entire surface of the display electrode 104 disposed on the front plate 102 is covered with a dielectric layer 107. The dielectric layer 7 can be formed of a dielectric material such as low-melting glass, and the thickness dimension is preferably in the range of 20 to 30 μm.

  The entire upper surface of the dielectric layer 107 is covered with the protective layer 108. The protective layer 108 can be an MgO film, and the thickness dimension is preferably in the range of 0.5 to 50 μm.

  On the other hand, as the back plate 103 disposed at a position facing one surface of the front plate 102, soda lime glass, so-called blue plate glass, or the like can be applied in the same manner as the front plate 102, and the thickness dimension is 1 to 8 mm. Is preferable, and about 2 mm is more preferable.

  A plurality of address electrodes 109 are arranged on the surface of the back plate 103 facing the front plate 102. These address electrodes 109 are formed in the same shape as the transparent electrode 105 and the bus electrode 106, and are provided at regular intervals so as to be orthogonal to the display electrode 104 in a plan view. The address electrode 109 may be a metal electrode such as an Ag thick film electrode, and the width dimension is preferably in the range of 100 to 200 μm.

  Further, the entire surface of the address electrode 109 is covered with a dielectric layer 110, and the dielectric layer 110 can be formed of a dielectric material such as low-melting glass. The range of 20-30 micrometers is preferable.

  On the upper surface of the dielectric layer 110, a partition wall 111 having a shape protruding in a direction perpendicular to the back plate 3 is disposed. These partition walls 111 are formed in a long shape, and are arranged on both sides of the address electrode 109 so that the longitudinal directions of the adjacent partition walls 111 are parallel to each other. In addition, a plurality of micro discharge spaces (hereinafter, discharge cells 112) partitioned into a predetermined shape by the barrier ribs 111 are formed in stripes in plan view.

  The partition wall 111 can be formed of a dielectric material such as low-melting glass, and the width dimension is preferably in the range of 10 to 500 μm, more preferably about 100 μm. Moreover, the height dimension of the partition 111 is 10-100 micrometers normally, and about 50 micrometers is preferable.

  In the discharge cell 112 according to this embodiment, when the front plate 102 and the back plate 103 are horizontally arranged, the barrier ribs 111 are arranged in parallel at predetermined intervals, that is, in a stripe shape. is called.

  Note that the structure of the discharge cell is not limited to such a stripe type, but is a grid type discharge cell 114 in which barrier ribs 113 are provided in a grid shape in plan view as shown in FIG. Alternatively, as shown in FIG. 6, a honeycomb-shaped (octagonal) discharge cell 116 may be formed by a pair of bent partition walls 115 that are subject to each other.

  Each of the discharge cells 112R, 112G, and 112B includes phosphor layers 117R and 117G each made of a phosphor that emits light of red (R), green (G), or blue (B) manufactured in this embodiment. , 117B are provided in a certain order. Further, a discharge gas is sealed in the hollow interior of each of the discharge cells 112R, 112G, and 112B, and at least one point where the display electrode 104 and the address electrode 109 intersect in plan view is provided. Furthermore, the thickness dimension of each fluorescent substance layer 117R, 117G, 117B is not specifically limited, The range of 5-50 micrometers is preferable.

  Each phosphor layer 117R, 117G, 117B is formed on the side or bottom surface of the partition wall. For these phosphor layers 117R, 117G, and 117B, a phosphor paste is first prepared by dispersing the phosphors described above in a mixture of a binder, a solvent, a dispersant, and the like. These phosphor pastes are adjusted to an appropriate viscosity, applied or filled in the corresponding discharge cells 112R, 112G, 112B, and finally dried or baked.

  The phosphor paste can be adjusted by a conventionally known method. In addition, as a method of applying or filling the phosphor paste to the discharge cells 112R, 112G, and 112B, various methods such as a screen printing method, a photoresist film method, and an ink jet method can be applied.

  The PDP 101 having the above-described configuration displays a display by selectively performing a trigger discharge between the address electrode 109 and one of the pair of display electrodes 104 and 104 during display. The discharge cell to be performed is selected. Thereafter, a sustain discharge is performed between the pair of display electrodes 104 and 104 inside the selected discharge cell, thereby generating ultraviolet rays caused by the discharge gas, and visible from the phosphor layers 117R, 117G, and 117B. It is designed to produce light.

  As described above, since the PDP 1 according to the present invention includes the discharge cell 112 manufactured using the above-described phosphor, it is possible to improve the emission intensity of the discharge cell 112, thereby increasing the emission intensity of the PDP 1. Improvements can be made.

Next, a method for manufacturing a phosphor and examples of the phosphor according to the present invention will be described.
[Example 1]
In this example, a green phosphor precursor 1 using Zn ₂ SiO ₄ : Mn ²⁺ as a raw material was synthesized, and the obtained precursor 1 was subjected to a desalting treatment, whereby the desalting treatment was performed. Precursors 2, 3, 4, and 5 were obtained. Furthermore, phosphors 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 are obtained by firing under two different conditions. Evaluation is made based on the relative light emission intensity before discharge, after discharge and after sputtering treatment in phosphors 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15. went.

First, a method for synthesizing the precursors 1, 2, 3, 4, and 5 will be described.
Colloidal silica containing 45 g of silicon dioxide (manufactured by Fuso Chemical Co., Ltd .: PL-3), 219 g of 28% ammonia water, and pure water were mixed and the liquid volume was adjusted to 1500 cc. did.
Further, 424 g of zinc nitrate hexahydrate (manufactured by Kanto Chemical Co., Ltd .: purity 99.0%) and 21.5 g of manganese nitrate hexahydrate (manufactured by Kanto Chemical Co., Ltd .: purity 98.0%) are purified water. A solution B was prepared by dissolving the solution in the solution and adjusting the amount of the solution to 1500 cc.

  As shown in FIG. 1, these A liquid and B liquid were respectively stored in the tanks 2 and 3 of the Y-shaped reactor 1 and kept at a temperature of 40 ° C. And A liquid and B liquid were supplied to the container 7 for maturation at the speed | rate of 1200 cc / min with pump P1, P2, and the deposit obtained by reaction was diluted with the pure water. Thereafter, solid-liquid separation was performed by pressure filtration, and further, the precursor 1 shown in Table 1 was obtained by drying at a temperature of 100 ° C. for 12 hours.

  On the other hand, in the precursor forming step described above, the precipitate obtained by the reaction is diluted with pure water, and then the diluted solution is ultrafiltered, whereby the electrical conductivity of the precursor is 30, 15, 0,. It adjusted to 3, 0.05 mS / cm, respectively. Thereafter, solid-liquid separation was performed by pressure filtration, and further, drying was performed at a temperature of 100 ° C. for 12 hours to obtain precursors 2, 3, 4, and 5 shown in Table 1.

The obtained precursors 1, 2, 3, 4, and 5 were fired at a temperature of 1240 ° C. for 3 hours in an atmosphere of 5% hydrogen and 95% nitrogen, whereby phosphors 1, 4, 7, and 10 were obtained. , 13 was obtained. Here, the firing conditions at this time are shown in Table 2 as firing conditions (1).
Further, the obtained precursors 1, 2, 3, 4, and 5 are fired at 1240 ° C. for 3 hours in an atmosphere of 20% oxygen to obtain phosphors 2, 5, 8, 11, and 14. It was. Here, the firing conditions at this time are shown in Table 2 as firing conditions (2).
Further, the obtained precursors 1, 2, 3, 4, and 5 were baked at 1240 ° C. for 3 hours in an atmosphere of 20% oxygen, and then in an atmosphere of 5% hydrogen and 95% nitrogen. Phosphors 3, 6, 9, 12, and 15 were obtained by firing at a temperature of 1240 ° C. for 3 hours. Here, the firing conditions at this time are shown in Table 2 as firing conditions (3).

  Subsequently, an equal amount of pure water is added to the phosphors 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15 described above, and the mixture is crushed by a pot mill. And distributed treatment. Thereafter, in order to remove the fine particles and the large particles, classification using a sieve was performed, and a phosphor dispersion solution was obtained.

Then, the classified phosphor dispersion solution and 2N hydrochloric acid are stored in the tanks 2 and 3 of the Y-shaped reactor 1 shown in FIG. 1, respectively, kept at a temperature of 40 ° C., and pumps P1 and P2 are used. The phosphor dispersion and 2N hydrochloric acid were simultaneously dropped into the aging container 7.
After completion of the dropping, the resulting mixed solution is stirred for 20 minutes, washed with pure water, and then dried at a temperature of 100 ° C. for 12 hours to complete a series of phosphor manufacturing steps.

Next, a method for evaluating the phosphor will be described.
The phosphor is evaluated using two indicators of the discharge maintenance ratio calculated based on the relative issuance intensity before discharge, after discharge and after sputtering, and the sputtering maintenance ratio, and the details will be described below. .

First, the discharge maintenance ratio will be described.
The obtained phosphors 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15 are introduced into a vacuum chamber of 0.1 to 1.5 Pa. Then, VUV was irradiated using an excimer 146 nm lamp (USHIO INC.). And the peak intensity of the green light obtained by irradiation is measured using a detector (manufactured by Otsuka Electronics Co., Ltd .: MCPD-3000), and the relative value when the emission intensity before the surface treatment is taken as 100. Luminescence intensity was calculated. Here, the relative light emission intensity calculated at this time was set as “relative light emission intensity before discharge” and shown in Table 1.

Further, each phosphor 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 is covered with an MgF ₂ plate having a thickness of 0.5 mm, and neon. After being introduced into the discharge space filled with 5% mixed gas of xenon gas, it was discharged for 1 hour. Then, the relative light emission intensity was calculated by the method described above. Here, the relative light emission intensity calculated at this time was set as “relative light emission intensity after discharge” and shown in Table 2.

  Furthermore, the above-mentioned relative light emission intensity after discharge is divided by the relative light emission intensity before discharge, and a value converted to a percentage is shown in Table 2 as “discharge maintenance ratio (%)”. The higher the numerical value, the lower the emission retention rate, the more the emission intensity is suppressed. That is, impurities, sub-salts, etc. contained in the phosphor are removed. Impurities and by-products are not removed.

Next, the sputtering maintenance rate will be described.
Argon gas in each of the phosphors 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 in a sputtering apparatus (manufactured by Sanyu Electronics Co., Ltd .: SC-701) The material was introduced into the discharge space filled with 100%, and a current of 5 mA was conducted to discharge for 5 minutes to perform sputtering. Then, the relative light emission intensity was calculated by the method described above. Here, the relative light emission intensity calculated at this time was set as “relative light emission intensity after sputtering” and shown in Table 2.

  Further, the above-mentioned relative light emission intensity after sputtering is divided by the relative light emission intensity before sputtering, that is, the above-mentioned relative light emission intensity before discharge, and a value converted into a percentage is shown as “Sputtering maintenance ratio (%)”. It was shown to. As for this sputtering maintenance factor, as the numerical value is higher, the reduction in emission intensity is suppressed, that is, impurities, sub-salts, etc. contained in the phosphor are removed, and the lower the numerical value, the more contained in the phosphor. Impurities and by-products are not removed.

  As a result, the phosphors 1, 2, and 3 that were not desalted in the precursor formation step had a discharge maintenance rate and a sputtering maintenance rate of about 65 to 75% regardless of the firing conditions. On the other hand, among phosphors 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15 that have been desalted in the precursor formation step, firing conditions (3) The phosphors 6, 9, 12, and 15 fired under the above conditions have a discharge maintenance ratio and a sputtering maintenance ratio of 90% or more, and the phosphor 4 fired under the firing conditions (1) and (2). , 5, 7, 8, 10, 11, 13, and 14, it was found that the light emission intensity was hardly reduced after discharge or after sputtering.

[Example 2]
In the first firing step, the precursor 4 obtained in Example 1 was fired in an atmosphere containing 20% oxygen at a temperature of 900 ° C. for 1, 3, 5, and 9 hours, respectively, and then the second firing. In the process, firing was performed for 3 hours at a temperature of 1240 ° C. in an atmosphere of 5% hydrogen and 95% nitrogen. 16, 17, 18, 19 were obtained.
Further, only the firing temperature in the first firing step was changed to 1240 ° C. to obtain phosphors 20, 21, 22, and 23.
Furthermore, only the firing temperature in the first firing step was changed to 1300 ° C. to obtain phosphors 24, 25, 26, and 27.
Furthermore, only the firing temperature in the first firing step was changed to 1420 ° C., and phosphors 28, 29, 30, and 31 were obtained.

  Each of the obtained phosphors 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, and 31 was subjected to the same procedure as in Example 1 before discharge. The relative light emission intensity after discharge and after sputtering was calculated and shown in Table 3 together with the discharge retention rate and sputtering retention rate.

  As a result, in the first firing step, phosphors fired at the same firing temperature with only the firing time changed, for example, phosphors 16, 17, 18, and 19 fired at 900 ° C. The phosphors 17 and 18 fired with the firing time set to 3 hours and 5 hours are more relative to the phosphors 16 and 19 fired with the firing time set to 1 hour and 9 hours. It was found that the emission intensity, the discharge maintenance rate, and the sputtering maintenance rate were high. This tendency is similarly observed in the phosphors fired at the firing temperatures of 1240 ° C., 1300 ° C., and 1420 ° C., respectively. Among them, among the phosphors 20, 21, 22, 23, 24, 25, 26 and 27 whose firing temperatures are set to 1240 ° C. and 1300 ° C., the fluorescence whose firing time is set to 3 hours and 5 hours. The bodies 21, 22, 25, and 26 were found to have this tendency more markedly than phosphors fired under other conditions.

[Example 3]
The precursor 4 obtained in Example 1 was baked for 3 hours at a temperature of 1240 ° C. in an atmosphere containing 20% oxygen in the first baking step, and then 5% hydrogen in the second baking step. It was baked for 1, 3, 5, and 9 hours at a temperature of 700 ° C. in a 95% nitrogen atmosphere, and further subjected to pulverization treatment, dispersion treatment, acid treatment, and drying treatment in the same manner as in Example 1. The bodies 32, 33, 34 and 35 were obtained.
Further, only the firing temperature in the second firing step was changed to 900 ° C., and phosphors 36, 37, 38, 39 were obtained.
Furthermore, only the firing temperature in the second firing step was changed to 1280 ° C. to obtain phosphors 40, 41, 42, and 43.
Furthermore, only the firing temperature in the second firing step was changed to 1420 ° C. to obtain phosphors 44, 45, 46, and 47.

  Each of the obtained phosphors 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47 was subjected to the same procedure as in Example 1 before discharge. The relative emission intensity after discharge and after sputtering was calculated and shown in Table 4 together with the discharge retention rate and sputtering retention rate.

  As a result, in the second firing step, phosphors fired at the same firing temperature with only the firing time changed, for example, phosphors 32, 33, 34, and 35 fired at 700 ° C. The phosphors 33 and 34 fired with the firing time set to 3 hours and 5 hours are more phosphorous than the phosphors 32 and 35 fired with the firing time set to 1 hour and 9 hours. It was found that the relative emission intensity, the discharge maintenance ratio and the sputtering maintenance ratio were high. This tendency is similarly observed in phosphors fired at 900 ° C., 1280 ° C., and 1420 ° C., respectively. Among them, among the phosphors 36, 37, 38, 39, 40, 41, 42 and 43 whose firing temperatures are set to 900 ° C. and 1280 ° C., the fluorescence whose firing time is set to 3 hours and 5 hours. The bodies 37, 38, 41, and 42 were found to have this tendency more markedly than the phosphors fired under other conditions.

  As described above, according to the phosphor manufacturing method, the phosphor and the plasma display panel according to the present invention, in the phosphor manufacturing method for forming the phosphor precursor by the liquid phase method, from the start to the end of the precursor formation. A desalting step for performing a desalting treatment during or immediately after the completion, a first firing step for performing a firing treatment on the precursor after the desalting treatment in an oxygen-containing atmosphere under a predetermined condition, and a step after the firing treatment And a second baking step in which the precursor is baked under a predetermined condition in a weakly reducing atmosphere, so that impurities, sub-salts, etc. present in the phosphor raw material mixture are removed by desalting. After that, further by performing a baking treatment under predetermined conditions, even if impurities or subsalts remain in the phosphor salt mixture after the desalting treatment, impurities or subsalts are removed. Burn reliably As a result, discoloration of the phosphor, uneven firing, damage to the phosphor body due to sputtering or VUV irradiation, and the like can be prevented, and the emission intensity of the phosphor and the plasma display panel can be improved. .

It is the schematic which shows a Y-shaped reaction apparatus. It is the schematic which shows a general reaction apparatus. It is the schematic which shows a double jet reactor. It is a perspective view which shows an example of the plasma display panel which concerns on this invention. It is a perspective view which shows the structure of another discharge cell. It is a perspective view which shows the structure of another discharge cell.

Explanation of symbols

1 Y-shaped reactor 11 Reactor 21 Double jet reactor 101 PDP

Claims (8)

In a method for producing a phosphor that forms a phosphor precursor by a liquid phase method,
A desalting step of performing a desalting treatment from the start to the end of precursor formation or immediately after the end;
A first firing step of performing a firing treatment under predetermined conditions in an oxygen-containing atmosphere on the precursor after the desalting treatment;
A phosphor manufacturing method comprising: a second baking step of baking the precursor after the baking treatment under a predetermined condition in a weakly reducing atmosphere.   The method for producing a phosphor according to claim 1, wherein the electrical conductivity at the end of the precursor formation is 0.01 to 20 mS / cm.   The method for producing a phosphor according to claim 1 or 2, wherein a firing temperature in the first firing step is 1000 to 1400 ° C.   The method for producing a phosphor according to any one of claims 1 to 3, wherein a firing time of the first firing step is 2 to 6 hours.   The method for producing a phosphor according to any one of claims 1 to 4, wherein a firing temperature in the second firing step is 800 to 1400 ° C.   The method for producing a phosphor according to any one of claims 1 to 5, wherein a firing time of the second firing step is 2 to 6 hours.   A phosphor manufactured by the manufacturing method according to any one of claims 1 to 6.   A plasma display panel comprising a discharge cell manufactured using the phosphor according to claim 7.

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