JP2006306959A - Fluorescent substance, method for producing fluorescent substance, and plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a fluorescent substance, capable of realizing improvement and stability of emission intensity, to provide the fluorescent substance given by the method, and to provide a plasma display panel given by utilizing the same. <P>SOLUTION: This method for producing the fluorescent substance has a firing process for firing a raw material mixture containing a fluorescent substance component at a high temperature or a firing process for firing a synthetic material of a solution containing the fluorescent substance component after drying the synthetic material, wherein the method includes one or more processes for conducing the firing in an oxygen-containing atmosphere and the oxygen-containing atmosphere has a dew point of ≤10°C. The fluorescent substance is given by the method. The plasma display panel has a discharge cell produced by using the fluorescent substance. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a phosphor, and more particularly to a method for manufacturing a phosphor suitable for a plasma display panel.

  As a method for producing a 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.

A manufacturing method (refer to Patent Document 1) of an aluminate phosphor [(Ba _0.9 , Eu _0.1 ) MgAl ₁₀ O ₁₇ etc.] having improved luminous efficiency by a solid phase method is also used in the manufacturing process by a liquid phase method. There is a disclosure of a technique for producing an inorganic phosphor having sufficient light emission characteristics without causing discoloration, uneven firing, and the like (see Patent Document 2).

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

However, the phosphor obtained by the liquid phase method has a problem that many impurities existing in the precursor precipitation medium are mixed, and the emission intensity, discoloration, and uneven firing are improved compared to the solid phase method. However, this is not always sufficient in terms of fluctuations in emission intensity due to firing lots.
Japanese Patent Laid-Open No. 10-110165 JP 2000-183643 A

  The present invention has been made in view of the above circumstances, and a phosphor manufacturing method capable of improving the emission intensity and stability, the phosphor obtained by the manufacturing method, and a plasma using the same. An object is to provide a display panel.

The above object of the present invention has been achieved by the following constitution. That is,
(Claim 1)
Baking in an oxygen-containing atmosphere in a method for producing a phosphor having a firing step of firing a raw material mixture containing a phosphor component at a high temperature, or a firing step of firing a composite of a solution containing a phosphor component after drying And the oxygen-containing atmosphere has a dew point of 10 ° C. or less.

(Claim 2)
The method for producing a phosphor according to claim 1, wherein the phosphor is fired in a weakly reducing atmosphere after firing in an oxygen-containing atmosphere having a dew point of 10 ° C or lower.

(Claim 3)
The method for producing a phosphor according to claim 1 or 2, wherein the step of firing in an oxygen-containing atmosphere having a dew point of 10 ° C or lower is 1000 to 1400 ° C.

(Claim 4)
A phosphor produced by the production method according to claim 1.

(Claim 5)
A plasma display panel comprising a discharge cell manufactured using the phosphor according to claim 4.

  The phosphor obtained by the present invention is excellent in emission intensity, hardly damaged, and is optimal for a plasma display panel.

  Hereinafter, the present invention will be described in more detail.

  The method for producing the phosphor of the present invention may be a solid phase method or a liquid phase method, but as described above, the liquid phase method is more suitable for obtaining a compositionally uniform and highly pure fine particle phosphor.

  As the liquid phase method, a general method such as a sol-gel method or a crystallization method can be used.

The method for producing an inorganic phosphor precursor by the sol-gel method generally means that an element (metal) used for a matrix, an activator or a coactivator is, for example, Si (OCH ₃ ) ₄ or Eu ³⁺ (CH ₃ COCHCOCH ₃ ) ₃ of a metal alkoxide or metal complex or their organic solvent solution to double alkoxide make the addition of elemental metal _{(Al (OC 4 H 9)} 3 2-butanol solution was added to metallic magnesium make Mg [Al (OC ₄ H ₉ ) ₃ ] ₂ etc.), a metal halide, a metal salt of an organic acid, a necessary amount as a simple metal, and a thermal or chemical polycondensation method.

  The method for producing an inorganic phosphor precursor by the crystallization method is 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. A solid phase sometimes precipitates from the liquid phase, which is generally referred to as a crystallization phenomenon, and means a production method by physical and chemical operations that can cause the occurrence of such a crystallization phenomenon.

  As the oxygen-containing atmosphere, the oxygen concentration is preferably 1 to 50% by volume, and more preferably 10 to 30% by volume.

  The oxygen-containing atmosphere preferably has a dew point of 10 ° C or lower, and more preferably 7 ° C or lower. After substituting the inside of the core in the firing furnace with an oxygen-containing atmosphere having a dew point of 10 ° C. or lower, it is preferably held at 1000 to 1400 ° C., more preferably 1100 to 1300 ° C.

  Furthermore, after baking in an oxygen-containing atmosphere with a dew point of 10 ° C. or lower, baking in a weakly reducing atmosphere is more preferable. In one firing, one cycle consists of raising the temperature from room temperature to a predetermined temperature, maintaining the predetermined temperature, and lowering the temperature to room temperature. When the temperature is lowered to room temperature, it may be returned to the atmospheric atmosphere once.

  The weakly reducing atmosphere preferably has an oxygen concentration of 100 ppm or less, and more preferably 10 ppm or less.

(Phosphor)
Specific examples of the compound of the inorganic phosphor of the present invention thus obtained are shown below, but are 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 ) 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} : Ce3 +, 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: Eu2 +
_{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 : Eu3 ⁺
RL-14: (Y, Gd ) BO 3: Eu 3+
As the phosphor according to the present invention, the above GL-14: Zn ₂ SiO ₄ : Mn ²⁺ is particularly preferable.

  Next, a method for manufacturing the phosphor according to the present invention will be described. The method for producing a vacuum ultraviolet-excited phosphor is obtained in a precursor forming step for forming a phosphor precursor, a firing step in which a precursor obtained in the precursor forming step is fired to obtain phosphor particles, and a firing step. An etching process for removing impurities and the like by performing an etching process on the surface of the phosphor particles.

(Precursor formation step)
First, a precursor formation process is demonstrated. Any method may be used in the precursor formation step, but it is particularly preferable to synthesize the precursor by a liquid phase method (also referred to as “liquid phase synthesis method”). A precursor is an intermediate product of a phosphor, and, as will be described later, phosphor particles can be obtained by firing this precursor at a predetermined temperature in a firing step.

  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 phosphors are produced while repeating the solid-phase reaction and the pulverization process, it is possible to obtain particles with a fine particle size without performing the pulverization process, and the crystals due to the stress applied during pulverization It is possible to prevent internal lattice defects and prevent a decrease in luminous 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 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 gas phase to the solid phase when the physical or chemical environment changes due to cooling, evaporation, pH adjustment, concentration, etc., 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, as the solvent for applying the reaction crystallization method, any solution can be applied as long as the reaction raw material is dissolved, but water is preferable from the viewpoint of easy control over the degree of supersaturation. When a plurality of reaction raw materials are used, the order in which the raw materials are added may be simultaneous or different, and an appropriate order can be appropriately selected according to the 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 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 one of preferred embodiments 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 this protein include gelatin, water-soluble protein, and water-soluble glycoprotein. Specific examples include albumin, ovalbumin, casein, soy protein, synthetic protein, and protein synthesized by genetic engineering.

  Examples of gelatin include lime-processed gelatin and acid-processed gelatin, and these may be used in combination. Furthermore, a hydrolyzate or 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 affected 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 very 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 formation step described above, as described above, the particle size is controlled as appropriate to synthesize the precursor, and if necessary, the precursor is filtered, evaporated to dryness, centrifuged, or the like. After that, preferably, washing and desalting treatment steps are performed.

  The desalting treatment 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, ultrafiltration A method using a film or the like can be applied.

  The desalting step may be performed immediately after the precursor formation is completed. Further, it may be carried out a plurality of times depending on the reaction conditions of the raw materials.

  After the desalting treatment step, a drying step may be further performed. The drying step is preferably performed after washing or desalting, and can be performed by any method such as vacuum drying, airflow drying, fluidized bed drying, and spray drying. The drying temperature is not particularly limited, but it is preferable that the temperature used is equal to or higher than the temperature at which the solvent used evaporates. If the drying temperature is too high, baking is performed simultaneously with drying, and subsequent baking treatment is not performed. Specifically, since a phosphor is obtained, the temperature is more preferably in the range of 50 to 300 ° C.

(Baking process)
Next, the firing process will be described. The phosphors according to the present invention, such as rare earth borate phosphors, silicate phosphors and aluminate phosphors, can be obtained by firing each precursor. Here, the conditions (baking conditions) for the baking treatment will be described.

  Any method may be used in the firing step, and the firing temperature and time may be appropriately adjusted within the scope of the present invention. For example, a desired phosphor can be obtained by filling the precursor in an alumina boat and firing it at a predetermined temperature in a predetermined gas atmosphere.

  As the baking apparatus (baking container), any apparatus known at present can be used. For example, a box furnace, a crucible furnace, a cylindrical tube type, a boat type, a rotary kiln and the like are preferably used.

  Moreover, you may add a sintering inhibitor as needed at the time of baking. 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 forming the precursor, or a powdery sintering inhibitor may be mixed with the dried precursor and fired.

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 .

  Furthermore, you may give a reduction process or an oxidation process after baking as needed. In addition, after the firing step, cooling treatment, surface treatment, dispersion treatment, or the like may be performed, or classification 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 known cooling methods. For example, either a method of lowering the temperature by leaving alone or a method of forcibly lowering the temperature while controlling the temperature using a cooler. It may be.

(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 remarkable 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, It is possible to suppress a decrease in crystallinity of the phosphor and prevent a decrease in emission intensity by preventing excitation energy from being captured by the surface defects of the phosphor. Further, if 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.

(Distributed processing)
Next, the distributed processing process will be described. In the present invention, the following dispersion treatment is preferably performed on the phosphor particles obtained in the firing step.

  For example, a high speed agitation type impeller type disperser, colloid mill, roller mill, ball mill, vibrating ball mill, attritor mill, planetary ball mill, sand mill, etc. Examples thereof include those that are atomized by both, dry type dispersers such as a cutter mill, a hammer mill, and a jet mill, an ultrasonic disperser, and a high-pressure homogenizer.

  Among these, in the present invention, it is particularly preferable to use a wet media type disperser that uses a medium, and it is more preferable to use a continuous wet media type disperser capable of continuous dispersion treatment. A mode in which a plurality of continuous wet media type dispersers are connected in series is also applicable. Here, “continuous dispersion treatment is possible” means that at least the phosphor and the dispersion medium are dispersed and supplied to the disperser without interruption at a constant quantity ratio per hour, and at the same time, manufactured in the disperser. The dispersion is discharged from the disperser without interruption 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 dispersion treatment step in the phosphor manufacturing method, the dispersion chamber container (vessel) can be appropriately selected from a vertical type and a horizontal type.

(Etching process)
Next, the surface treatment process by etching 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 the etching process on the phosphor particles having few or no projections on the particle surface.

  In addition, it is possible to select appropriately according to the impurities on the surface of the phosphor particles. For example, a fine method or a physical method of scraping the surface by ion sputtering may be used. It is effective to use a chemical method such as soaking the surface to dissolve impurities on the surface. 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 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.

  In addition, after etching, it is preferable to perform a water washing process or the like to remove the etching solution.

(Plasma display panel)
Finally, a plasma display panel (hereinafter abbreviated as 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 with reference to an AC type PDP.

  As shown in FIG. 1, the PDP 1 in the present embodiment has a front plate 10 formed into a flat plate shape and a shape substantially the same as that of the front plate 10 and disposed at a position facing one surface of the front plate 10. And a face plate 20. Among these substrates 10 and 20, the front plate 10 transmits visible light emitted from the discharge cells, displays various information on the substrate, and functions as a display screen of the PDP 1.

  The front plate 10 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.

  The front plate 10 has a plurality of display electrodes 11 arranged at regular intervals on the surface of the front plate 10 facing the back plate 20. These display electrodes 11 are provided with a transparent electrode 11a formed in a wide band shape and a pass electrode 11b formed in the same shape as the transparent electrode 11a, and the pass electrode 11b is laminated on the upper surface of the transparent electrode 11a. It has a structure.

  The display electrodes 11 are orthogonal to the barrier ribs 31 in a plan view, and two display electrodes 11 are 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 11a, and the sheet resistance is preferably 100Ω or less. The width of the transparent electrode 11a is preferably in the range of 10 to 200 μm.

  The pass electrode 11b is for lowering the resistance, and is formed by sputtering of Cr / Cu / Cr or the like. Moreover, the width dimension of the pass electrode 11b is formed smaller than the transparent electrode 11a, and the range of 5-50 micrometers is preferable.

  The entire surface of the display electrode 11 disposed on the front plate 10 is covered with a dielectric layer 12. The dielectric layer 12 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 12 is covered with the protective layer 13. The protective layer 13 can be an MgO film, and the thickness dimension is preferably in the range of 0.5 to 50 μm.

  On the other hand, the rear plate 20 disposed at a position facing one surface of the front plate 10 is applicable to soda lime glass, so-called blue plate glass, etc., as with the front plate 10, and has a thickness dimension of 1 to 8 mm. The range is preferable, and about 2 mm is more preferable.

  A plurality of address electrodes 21 are arranged on the surface of the back plate 20 facing the front plate 10. These address electrodes 21 are formed in the same shape as the transparent electrodes 11a and the pass electrodes 11b, and are provided at regular intervals so as to be orthogonal to the display electrodes 11 in plan view. The address electrode 21 can 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 21 is covered with a dielectric layer 22, and the dielectric layer 22 can be formed of a dielectric material such as low-melting glass, and its thickness dimension is 20 to 20 mm. A range of 30 μm is preferred.

  On the upper surface of the dielectric layer 22, a partition wall 30 having a shape protruding in a direction perpendicular to the back plate 20 is disposed. These partition walls 30 are formed in a long shape, and are arranged on both sides of the address electrode 21 so that the longitudinal directions of the adjacent partition walls 30 are parallel to each other. Further, a plurality of micro discharge spaces (hereinafter referred to as discharge cells 31) partitioned in a predetermined shape by the barrier ribs 30 are formed in stripes in plan view.

  The partition wall 30 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, and more preferably about 100 μm. The height of the partition wall 30 is usually in the range of 10 to 100 μm, and preferably about 50 μm.

  The discharge cell 31 in this embodiment is called a stripe type because the barrier ribs 30 are arranged in parallel, that is, in stripes at predetermined intervals when the front plate 10 and the back plate 20 are arranged horizontally. It is.

  The structure of the discharge cell is not limited to such a stripe type, and may be a grid type discharge cell provided in a grid shape in plan view, or a set of bent cells that are subject to each other. A honeycomb-shaped (octagonal) discharge cell may be formed by the partition walls.

  Each discharge cell 31R, 31G, 31B includes phosphor layers 35R, 35G made of phosphors that emit light in any of red (R), green (G), and blue (B) manufactured in the present invention. Any one of 35B is provided in a fixed order. Further, a discharge gas is sealed in the hollow interior of each of the discharge cells 31R, 31G, and 31B, and at least one point where the display electrode 11 and the address electrode 21 intersect in a plan view is provided. Furthermore, the thickness dimension of each fluorescent substance layer 35R, 35G, 35B is not specifically limited, The range of 5-50 micrometers is preferable.

  Each phosphor layer 35R, 35G, 35B is formed on the side or bottom of the partition. For these phosphor layers 35R, 35G, and 35B, a phosphor paste is first prepared by dispersing the above-described phosphor 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 31R, 31G, 31B, and finally dried or baked.

  The phosphor paste can be prepared by a conventionally known method. Further, as a method of applying or filling the phosphor paste to the discharge cells 31R, 31G, and 31B, various methods such as a screen printing method, a photoresist film method, and an ink jet method can be applied.

  The PDP 1 configured as described above performs display by selectively performing trigger discharge between the address electrode 21 and any one of the pair of display electrodes 11 and 11 during display. The discharge cell to be performed is selected. Thereafter, a sustain discharge is performed between the pair of display electrodes 11 and 11 inside the selected discharge cell to generate ultraviolet rays caused by the discharge gas, and visible from the phosphor layers 35R, 35G, and 35B. It is designed to produce light.

  As described above, since the PDP 1 according to the present invention includes the discharge cell 31 manufactured using the above-described phosphor, it is possible to improve the emission intensity of the discharge cell 31, thereby increasing the emission intensity of the PDP 1. Improvements can be made.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, the embodiment of this invention is not limited to these. Unless otherwise specified, “%” in the examples represents “mass%”.

Example 1 (Synthesis of green phosphor by solid phase method)
Composition formula: Zn ₂ SiO ₄ : Mn ²⁺
As phosphor materials, silicon oxide, zinc oxide, and manganese carbonate were weighed to be 26%, 64%, and 10%, respectively, and thoroughly mixed with a ball mill. Thereafter, the inside of the firing furnace was replaced with an atmosphere of 30% by volume of oxygen having different dew points as shown in Table 1, and fired at 1200 ° C. for 3 hours to obtain a green phosphor.

  An equal amount of pure water is added to the phosphor obtained by firing and pulverized and dispersed using a pot mill. After pulverization, classification is performed by sieving to remove fine particles and large particles.

  Subsequently, the classified phosphor dispersion was kept at 40 ° C. in a reaction vessel and acid-treated with 2 mol / L hydrochloric acid. After completion of the addition, the mixture is stirred for 20 minutes and then thoroughly washed with pure water. Subsequently, it dried at 100 degreeC for 12 hours, and obtained fluorescent substance powder.

  Relative emission intensity is measured by irradiating each phosphor with vacuum ultraviolet rays using an excimer 146 nm lamp (manufactured by USHIO INC.) In a vacuum chamber of 0.1 to 1.5 Pa, and detecting the obtained green light as a detector. The strength was measured using (MCPD-3000: manufactured by Otsuka Electronics Co., Ltd.). The peak intensity of luminescence was determined as a relative value with the luminescence intensity before acid treatment being 100. The results are shown in Table 1.

Example 2
The fired green phosphor obtained in Example 1 was further replaced with an atmosphere of 100% by volume of nitrogen and baked at 1200 ° C. for 3 hours. Crushing, dispersion, acid treatment, and drying were performed in the same manner as in Example 1, and the relative emission intensity of the obtained phosphor powder was measured. The results are shown in Table 2.

Example 3
In Example 1, after mixing the phosphor raw materials, the inside of the firing furnace was replaced with an atmosphere having an oxygen capacity of 30% with different dew points as shown in Table 3, and baked at 900 ° C. or 1500 ° C. for 3 hours. Crushing, dispersion, acid treatment, and drying were performed in the same manner as in Example 1, and the relative emission intensity of the obtained phosphor powder was measured. The results are shown in Table 3.

Example 4
Liquid A was prepared by mixing 219 g of colloidal silica (manufactured by Fuso Chemical Co., Ltd .: PL-3) containing 45 g of silicon dioxide and 219 g of 28% ammonia water in pure water to adjust the liquid volume to 1500 ml. Simultaneously, 424 g of zinc nitrate hexahydrate (Kanto Chemical Co., Ltd., purity 99.0%) and 21.5 g of manganese nitrate hexahydrate (Kanto Chemical Co., Ltd., purity 98.0%) were dissolved in pure water. Liquid B was made up to 1500 ml.

  After keeping A liquid and B liquid at 40 degreeC, it supplied to the Y-shaped reactor shown in FIG. 1 with the addition rate of 1200 ml / min using the roller pump. The aqueous dispersion containing the precipitate obtained by the reaction was washed by decantation until the electrical conductivity shown in Table 1 was reached, and then subjected to pressure filtration for solid-liquid separation. Subsequently, drying was performed at 100 ° C. for 12 hours to obtain a dried precursor.

  Next, the obtained precursor was replaced with an atmosphere having an oxygen capacity of 30% having different dew points as shown in Table 4 in the firing furnace and fired at 1200 ° C. for 3 hours to obtain a green phosphor.

  The phosphor obtained by firing was crushed, dispersed, acid-treated and dried in the same manner as in Example 1, and the relative emission intensity of the obtained phosphor powder was measured. The results are shown in Table 4.

Example 5
The fired green phosphor obtained in Example 4 was further replaced with an atmosphere of 100% by volume of nitrogen and baked at 1200 ° C. for 3 hours. Crushing, dispersion, acid treatment, and drying were performed in the same manner as in Example 1, and the relative emission intensity of the obtained phosphor powder was measured. The results are shown in Table 5.

Example 6
The dried precursor obtained in Example 4 was calcinated at 900 ° C. or 1500 ° C. for 3 hours by replacing the inside of the calcination furnace with an atmosphere of 30 vol% oxygen having different dew points as shown in Table 3. Crushing, dispersion, acid treatment, and drying were performed in the same manner as in Example 1, and the relative emission intensity of the obtained phosphor powder was measured. The results are shown in Table 6.

  In the present invention, it has been found that a phosphor including a step of firing in an oxygen-containing atmosphere having a dew point of 10 ° C. or lower has a high relative emission intensity and a stable emission intensity.

It is the schematic which shows an example of the plasma display panel using the fluorescent substance of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 AC type plasma display panel 10 Front plate 11 Display electrode 11a Transparent electrode 11b Pass electrode 12, 22 Dielectric layer 13 Protective layer 20 Back plate 21 Address electrode 30 Bulkhead 31 (R, G, B) Discharge cell 35 (R, G , B) Phosphor layer

Claims (5)

Baking in an oxygen-containing atmosphere in a method for producing a phosphor having a firing step of firing a raw material mixture containing a phosphor component at a high temperature, or a firing step of firing a composite of a solution containing a phosphor component after drying And the oxygen-containing atmosphere has a dew point of 10 ° C. or less. The method for producing a phosphor according to claim 1, wherein the phosphor is fired in a weakly reducing atmosphere after firing in an oxygen-containing atmosphere having a dew point of 10 ° C or lower. The method for producing a phosphor according to claim 1 or 2, wherein the step of firing in an oxygen-containing atmosphere having a dew point of 10 ° C or lower is 1000 to 1400 ° C. A phosphor produced by the production method according to claim 1. A plasma display panel comprising a discharge cell manufactured using the phosphor according to claim 4.

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