KR20010077792A - Method for preparing green zinc sulfide phosphors having spherical shape by gas phase fluxes - Google Patents

Abstract

PURPOSE: Provided is a preparation method of spherical green fluorescent material based on zinc sulfide of particle diameter of 5-12 micrometer which improves fluorescent coating layer and chargeability to enhance luminescence for the cathode ray tube and flat display. CONSTITUTION: The process of making fluorescent layer for cathode ray tube and flat display panel comprises mixing ZnS with activators such as Cu or Au compounds, Al containing adjuvant activator, S and 0.01-0.3wt% vapor phase flux containing not less than two halogens and baking at 800-1050 deg.C with sulfur and activated charcoal under reducing atmosphere of N2 or H2. The process is characterized in that boiling, decomposition and sublimation temperature of each vapor phase flux are under the baking temperature, the differences being not less than 80 deg.C. The vapor flux is selected from halogen derivatives of Bi, Ca, Sb, Sn, Al, Cu, Ga, Mg, Sr, In, Zn and ammonium halides.

Description

METHODS FOR PREPARING GREEN ZINC SULFIDE PHOSPHORS HAVING SPHERICAL SHAPE BY GAS PHASE FLUXES}

[Industrial use]

The present invention relates to a method for producing a spherical green phosphor based on zinc sulfide (ZnS), and in particular, a sulfide sulfide capable of improving the chargeability and phosphor coating surface (fluorescence film) for improving the brightness of cathode ray tubes and flat panel displays. It relates to a method for producing a linked spherical green phosphor.

[Prior art]

As a method of improving the brightness of the cathode ray tube, a method of basically improving the brightness of the phosphor itself is preferable. However, the brightness of the phosphor itself has not increased dramatically over the past decade. Accordingly, there have been many attempts to increase the brightness of the cathode ray tube by improving the phosphor coating surface rather than increasing the brightness of the phosphor itself.

Phosphor coating film of cathode ray tube spins after mixing and stirring various chemicals such as photocatalysts such as polyvinylalcohol (PVA) and sodium dichromate (SDC) or ammoniumdichromate (ADC), surfactant, and sensitizer, which form a film on the phosphor It is obtained by injecting, developing, and drying the glass panel by spin-coating, exposing, recovering, and drying. At this time, the luminance of the cathode ray tube is changed by the filling property of the phosphor stripe or the dot film. For example, when a microcrystal with a flat growing surface, that is, plate like hexagonal particles and spherical particles, is applied together, the glass panel surface and the phosphor particles are present. The degree of ultraviolet light (UV) reaching the PVA layer to cause a photocuring reaction is different. The ultraviolet light cannot reach the PVA layer between the glass panel surface and the phosphor particles by passing through the phosphor particles of several μm, but is diffusely reflected by the phosphor particles present in the phosphor coating film to reach the PVA layer.

In the case of spherical phosphor particles which are advantageous for diffuse reflection due to the phenomenon at the time of exposure, ultraviolet rays reach the PVA layer under the phosphor, which does not occur in the case of plate-shaped particles which cause photocuring reactions but are disadvantageous for diffuse reflection. Therefore, during post-exposure development, plate-shaped particles, which do not properly undergo photocuring reactions in the PVA layer below, fall off the glass panel and cause pinholes to reduce the overall filling ability (Lyuji Ozawa, VDH, Cathodoluminescene-Theory). and Application, 1989, and Peng Chao-Chi et.al, IDW, Preparation of spherical Particles of Y ₂ O ₂ S: Eu phosphor by flux, 1997).

Such spherical phosphors have been intensively studied not only for phosphors used in cold cathode ray tubes, but also for phosphors used in flat panel displays such as plasma displays, which have recently been commercialized. For example, a method of forming a plate-shaped Y ₂ O ₂ S: Eu phosphor by spherical surface melting process using an induction plasma (AKAlbessard et. Al, Asia Display, Phosphor layer made fospherical particle, 1995), Method of making spherical Y ₂ O ₂ S: Eu by conventional solid phase reaction using a suitable flux (Peng Chao-Chi et. Al, IDW, Preparation of spherical Particles of Y ₂ O ₂ S: Eu phosphor by flux, 1997) and spherical Y ₂ O ₂ S: Eu, Y ₂ SiO ₅ : Tb, Y ₂ SiO ₅ : Ce, Zn ₂ SiO ₄ : Mn, BAM: Eu using a spray pyrolysis method (J. Dimeler et. Al, SID digest, Production for high performance Micron sized spheriacl powders for display applications, 1999).

However, the result of the successful spherical manufacturing method for green ZnS: Cu, Al or ZnS: Au, Cu, Al and blue ZnS: Ag, Cl, Al phosphors mainly ZnS used in cathode ray tube none. In connection with this method, a method of forming a blue ZnS: Ag, Cl, Al phosphor by spherical phosphor surface melting process using an induction plasma has been attempted, but ZnS can be volatilized without melting during induction plasma treatment. For spherical phosphor particles, spherical phosphors could not be obtained (AKAlbessard et. Al, Conference of PTCOE, Preparation of spherical phosphors by thermal plasma treatment, 1996). In addition, the production of spherical phosphors by the conventional solid-phase synthesis method in which the raw materials including fluxes are mixed by high-temperature firing, washing with water, and dispersing is only Y ₂ O ₂ S: Eu mainly used in cathode ray tubes. . It is formed by the liquid phase at the reaction firing temperature is made by kinetics control (kinetics control) by Na _x S to perform the role of the raw material, the solvent at the same time is easily produced commercially.

The production of a green fluorescent substance based on ZnS mainly used in a conventional cathode ray tube uses the following method.

In the case of green phosphors such as ZnS: Cu, Al or ZnS: Au, Cu, Al, ZnS powder, activator, co-activator Cu, Al or Au, Cu, Al added A compound, a mixture of other fluxes such as NaCl, and sulfur are mixed and calcined at a temperature of 800 to 1100 ° C. under a reducing atmosphere, which is prepared by washing with water and dispersing (US Pat. No. 4,316,816, US Pat. No. 4,140,940, US Pat. 4,038, 205, US Pat. No. 3,657,142, or US Pat. No. 3,691,088. Looking at the above documents and related data, there is no example in which the flux is used with interest in shape or under certain principles in the production of phosphors based on ZnS. However, there are some literatures on the preparation of ZnS: Ag phosphors using compounds such as NaCl, BaCl ₂ and NH ₄ Cl as fluxes and analyzing the results of the fluxes. It only limits the removal of killer ions (Fe, Ni, Co) (ALSmith, J. Electrochem. Soc., Influence of fluxes on the cathodoluminescence of Zinc Sulfide Phophors, 1949). In addition, experiments on the effects of flux on the growth of ZnS: Cu, Al phosphors (H. Kawai et. Al, Jap. J. Appl. Phys., Effects of fluxes on particle growth of ZnS phosphor, 1981) However, it deals with the flux in the liquid phase at the firing reaction temperature, and whether the particle growth takes place in one step or in two steps is the phase at the reaction firing temperature of the metal sulfide, the reaction compound of the flux, that is, the liquid phase. It only deals with the consequences of dependence on solid or solid state.

In view of the problems of the prior art, the present invention provides a method for producing a spherical green phosphor by the solid phase synthesis method, which is commercially used using a flux (hereinafter referred to as a gas phase flux) which exists in a gaseous phase below a calcination reaction temperature. It is an object of the present invention to provide a method for producing a spherical green phosphor having an average particle diameter of 5 to 12 µm based on zinc sulfide as possible.

Another object of the present invention is to provide a method for producing a zinc sulfide-based spherical green phosphor which is capable of improving the chargeability and phosphor coating surface (fluorescent film) for improving the brightness of cathode ray tubes and flat panel displays.

FIG. 1 is an electron micrograph of a spherical phosphor prepared by mixing two kinds of gaseous fluxes of Example 1. FIG.

FIG. 2 is an electron micrograph of a spherical phosphor prepared by mixing two kinds of gaseous fluxes of Example 2. FIG.

3 is an electron micrograph of a plate-like phosphor prepared using only one liquid flux of Comparative Example 1. FIG.

FIG. 4 is an electron micrograph of a spherical phosphor prepared by mixing two kinds of gaseous fluxes of Example 3. FIG.

FIG. 5 is an electron micrograph of a plate-shaped phosphor prepared by mixing a gaseous flux and a liquid flux of Comparative Example 2. FIG.

FIG. 6 is an electron micrograph of a spherical phosphor prepared by mixing three kinds of gaseous fluxes of Example 4. FIG.

7 is an electron micrograph of a spherical phosphor having a non-uniform particle size distribution prepared using only one type of vapor phase flux of Comparative Example 5. FIG.

[Means for solving the problem]

The present invention to achieve the above object,

In the method for producing a spherical green phosphor based on zinc sulfide by a solid phase synthesis method,

a) iii) zinc sulfide;

Ii) Cu-containing compound, or Au-containing compound as activator,

Iii) Al-containing compounds as co-activators;

Viii) sulfur; And

Iii) two or more halogen-containing gas phase fluxes

Mixing; And

b) reducing the mixture obtained in step a) together with a mixture of sulfur and activated carbon

Firing at a temperature of 800 to 1050 ° C. under an atmosphere

It provides a method for producing a spherical green phosphor comprising a.

In another aspect, the present invention provides a spherical green phosphor prepared by the above production method.

In another aspect, the present invention provides a cathode ray tube or a flat panel display panel using a fluorescent film of a spherical green phosphor produced by the above production method.

Hereinafter, the present invention will be described in detail.

[Action]

The growth of particles in the presence of flux results in surface melting of raw material particles through liquid flux at the reaction temperature, the migration of these materials, and growth, or the process of gas phase etching by the reaction of the flux present in the gas phase with the raw particles at the reaction temperature. This occurs and grows through the redeposition of the material formed therefrom. The two particle growth processes differ greatly in the mass transfer of the mass transfer process.

When the mass transfer amount is low, that is, when the crystal growth occurs slowly due to low supersaturation, the thermodynamic factor is important because the time required for the active species adsorbed on the surface to move to a more stable site is important. Crystal growth proceeds in such a direction. In the case of ZnS, crystal growth occurs to expose 111 planes, thereby forming plate-like flat particles. On the other hand, when the amount of mass transfer is large, that is, when the degree of supersaturation increases, the reaction proceeds in a direction of rapidly decreasing the delivered active species, so the reaction rate factor is more important than the thermodynamic factor. As the growth rate increases, these crystal planes are exposed. In the case of ZnS, crystal growth occurs in a direction in which 100 planes and the like are exposed to form particles in a critically equilibrium state.

On the other hand, when the degree of supersaturation is very large, since the members do not rearrange the surface to form spherical particles that can lower the overall surface energy. Therefore, the present invention implements a method capable of sufficiently increasing the degree of supersaturation of the reactive active species in order to obtain a spherical ZnS phosphor, and uses a flux present in the gas phase at the reaction firing temperature for this purpose.

Particle growth reaction of ZnS by gas phase flux, that is, gas phase etching, redeposition process may be divided into five cases of the following reaction schemes 1 to 5.

Bi ₂ S ₃ (g) + ZnI ₂ (g)

ZnI ₂ (g) + S (g) ZnS (s) + I ₂ (g) or ZnI ₂ (g) + CS ₂ (g) ?? ZnS (s) + CI ₄ (g)

Bi ₂ S ₃ (g) + I ₂ (g) BiI ₃ (g) + S (g) or Bi ₂ S ₃ (g) + CI ₄ (g) ?? BiI ₃ (g) + CS ₂ (g)

Sb ₂ S ₃ (l) + ZnI ₂ (g)

ZnI ₂ (g) + S (g) ZnS (s) + I ₂ (g) or ZnI ₂ (g) + CS ₂ (g) ?? ZnS (s) + CI ₄ (g)

Sb ₂ S ₃ (l) + I ₂ (g) SbI ₃ (g) + S (g) or Sb ₂ S ₃ (l) + CI ₄ (g) ?? SbI ₃ (g) + CS ₂ (g)

SrS (s) + ZnBr ₂ (g)

ZnBr ₂ (g) + S (g) ZnS (s) + Br ₂ (g) or ZnBr ₂ (g) + CS ₂ (g) ?? ZnS (s) + CBr ₄ (g)

SrS (s) + Br ₂ (g) SrBr ₂ (g) + S (g) or SrS (s) + CBr ₄ (g) ?? SrBr ₂ (g) + CS ₂ (g)

ZnS (s) + Cl ₂ (g) or ZnCl ₂ (g) + CS ₂ (g) ?? ZnS (s) + CCl ₄ (g)

NH ₃ (g) + HCl (g)

HCl (g) + ZnS (s) ZnCl ₂ (g) + H ₂ S (g)

ZnCl ₂ (g) + S (g) ZnS (s) + Cl ₂ (g) or ZnCl ₂ (g) + CS ₂ (g) ?? ZnS (s) + CCl ₄ (g)

Metal halides, ie, gas halides such as M _x X _y , which may exist in the gas phase at the firing reaction temperature, form metal sufides such as M _z S through reaction with ZnS. Whether the gas phase (Scheme 1), liquid (Scheme 2), or solid phase (Scheme 3) is a significant problem at the firing reaction temperature. The produced metal sulfide reacts with the reaction product X ₂ or CX ₄ to produce gaseous flux, which is the original input, but the reaction rate for regenerating the gaseous flux is different depending on the phase of the metal sulfide. Therefore, excluding the quantitative aspect of the flux, the use of gaseous flux in Scheme 1 is advantageous to increase the supersaturation rate than the gaseous flux in Scheme 2, and the use of gaseous flux in Scheme 2 is It is advantageous to increase the degree of super saturation than to use gaseous flux.

There is also a gas phase melter that does not form a metal sulfide except ZnS as in Scheme 4 or Scheme 5. In addition to the gaseous flux and the metal flux produced initially, X ₂ or CX ₄ generated in the reaction process also participates in the gas phase etching and redeposition process of ZnS, as shown in Schemes 1 to 5.

The firing of the present invention proceeds after mixing the raw materials, filling it in the crucible and covering the lid. The process of heating up from the room temperature to the firing reaction temperature, and then stays at a constant reaction temperature for several hours. In this case, in the case of gaseous flux, unlike liquid flux, since the reaction can be easily released and removed from the crucible, it is necessary to increase the quantity. However, if only one type of gaseous flux is used in a quantitative way, when the temperature reaches the boiling point (bp) of the gaseous flux, excessive etching and redeposition occur instantaneously, resulting in excessive increase in particle size. The amount of the gaseous flux and the reaction product of the gaseous phase is increased to reduce the efficiency based on the amount of flux used. Therefore, not only one type of gaseous flux is used, but also two or more types are used to adjust the size of particles and increase the efficiency of the flux so that a certain amount of flux can be present in the gas phase in accordance with the temperature increase process. The boiling point, decomposition point, or sublimation point of each of the gaseous fluxes used is equal to or lower than the reaction baking temperature, and the boiling point, decomposition point, or sublimation point difference is preferably 80 ° C or more.

In the case of a liquid flux, it is initially injected with a raw material to form gaseous metal sulfide or ZnX ₂ , X ₂ , CX ₄ through surface melting and reaction to form a gas phase etching and redeposition process of ZnS. Is significantly lower than gaseous flux, and the degree of supersaturation of the material required for redeposition of ZnS cannot be sufficiently increased. In addition, when the gaseous flux and the liquid flux are used together, the gaseous flux forms spherical particles at the initial stage of the temperature raising process and the temperature of the firing reaction temperature and is released out of the crucible so that they do not contribute to further grain growth. However, the liquid flux remains and surrounds the spherical particles and continues to grow through volume diffusion with a low degree of supersaturation. The resulting particles appear in the form of plates. Therefore, in order to sufficiently increase the supersaturation during the temperature raising process and the initial maintenance of the reaction firing temperature, only the gaseous flux existing in the gas phase at the reaction firing temperature should be used as the flux injected with the raw materials. In addition, the liquid flux is vaporized so that spherical grown particles retain their shape and the growth of the particles stops when the reaction firing temperature is maintained. Do not use simultaneously with flux.

On the other hand, liquid phase metal sulfide is produced when gaseous flux is used, but the amount of gaseous flux injected with the raw material is small in the production of phosphors of commercially available particle size, and thus the effect thereof is negligible. At the same time, sulfur is added to the raw material input to achieve crystal growth of ZnS by etching and redeposition, or a mixture of activated carbon and sulfur must be added together with the upper part of the raw material in the crucible to generate CS ₂ during the reaction firing process.

For example, in order to manufacture green ZnS: Cu, Al phosphors, Cu-containing compounds and co-activators containing 80 to 260 ppm of Cu as an activator in the raw material of ZnS powder as a parent An Al containing compound containing 40 to 200 ppm of Al, and 1 to 5% by weight of sulfur are added. Then, the gaseous flux shown in Table 1 is mixed so that two or more kinds thereof are added so that the total amount of flux is 100 to 3000 ppm, preferably 200 to 800 ppm. After mixing them for 3 to 24 hours, the mixture is placed in an alumina or quartz crucible and a mixture of activated carbon and sulfur is placed on the raw material composition, and then the lid is fired under a reducing atmosphere of nitrogen or hydrogen. During firing, the temperature increase rate is 2 to 20 ° C./min, and the firing temperature is maintained at a range of 800 to 1050 ° C. In this manner, spherical green ZnS: Cu, Al phosphors can be obtained, but the average particle size after washing with water is 5 to 12 µm. In the color coordinates indicated by CIE 1931, x is 0.270 to 0.300, and y is 0.605 to 0.625.

In another example, in order to manufacture green ZnS: Au, Cu, Al phosphors, Au-containing compounds containing 20 to 150 ppm of Au as an activator in a ZnS powder-like raw material as a parent, 60 to 200 Cu A Cu-containing compound containing ppm, an Al-containing compound containing 40 to 200 ppm of Al as a co-activator, and 1 to 5% by weight of sulfur are added. Then, the gaseous flux shown in Table 1 is mixed and two or more thereof are added so that the total amount of the flux is 100 to 1500 ppm, preferably 100 to 600 ppm. After mixing them for 3 to 24 hours, the mixture is placed in an alumina or quartz crucible and a mixture of activated carbon and sulfur is placed on the raw material composition, and then the lid is fired under a reducing atmosphere of nitrogen or hydrogen. During firing, the temperature increase rate is 2 to 20 ° C./min, and the firing temperature is maintained at a range of 800 to 1050 ° C. In this manner, spherical green ZnS: Au, Cu, Al phosphors can be obtained, and the average particle size after washing with water is 8 to 20 µm. In the color coordinates indicated by CIE 1931, x is 0.280 to 0.315, and y is 0.600 to 0.620.

Table 1 below shows the characteristics of the vapor phase flux that can be used to prepare spherical phosphors based on ZnS.

division flux Flux bp (℃) (including sublimation temperature and decomposition temperature) Produce metal sulfide Characteristics of Metal Sulphide Formed (mp / bp) Scheme 1 Category BiBr ₃ 453 (bp) Bi ₂ S ₃ 685 (dec.) BiCl ₃ 441 (bp) Bi ₂ S ₃ 685 (dec.) BiI ₃ 500 (bp) Bi ₂ S ₃ 685 (dec.) CaBr ₂ 810 (bp) CaS dec. Scheme 2 Classification SbBr ₃ 288 (bp) Sb ₂ S ₃ 547 (mp) SbCl ₃ 221 (bp) Sb ₂ S ₃ 547 (mp) SbF ₃ 376 (bp) Sb ₂ S ₃ 547 (mp) SbI ₃ 401 (bp) Sb ₂ S ₃ 547 (mp) SnBr ₄ 202 (bp) SnS ₃ / SnS dec./880 (mp) SnBr ₂ 620 (bp) SnS 880 (mp) SnCl ₄ 113 (bp) SnS ₃ / SnS dec./880 (mp) SnCl ₂ 623 (bp) SnS 880 (mp) SnI ₄ 340 (bp) SnS ₃ / SnS dec./880 (mp) SnI ₂ 720 (bp) SnS 880 (mp) Scheme 3 Classification AlBr ₃ 257 (bp) Al ₂ S ₃ 1100 (mp) AlCl ₃ 180 (subl.) Al ₂ S ₃ 1100 (mp) AlI ₃ 386 (bp) Al ₂ S ₃ 1100 (mp) CuCl ₂ 993 (bp) Cu ₂ S / CuS 1130 (mp) / 220 (dec.) CuF ₂ 950 (bp) Cu ₂ S / CuS 1130 (mp) / 220 (dec.) GaBr ₃ 279 (bp) Ga ₂ S ₃ 1250 (mp) GaCl ₃ 201 (bp) Ga ₂ S ₃ 1250 (mp) GaF ₃ 950 (subl.) Ga ₂ S ₃ 1250 (mp) GaI ₃ 345 (subl.) Ga ₂ S ₃ 1250 (mp) MgI ₂ 700 (dec.) MgS dec.> 2000 SrBr ₂ dec. SrS mp.> 2000 SrI ₂ dec. SrS mp.> 2000 InCl ₃ 300 (subl.) In ₂ S ₃ 1050 (mp) Scheme 4 Category ZnBr ₂ 650 (bp) ZnS 1020 (dec), 1185 (subl) ZnCl ₂ 732 (bp) ZnS 1020 (dec), 1185 (subl) ZnI ₂ 624 (bp) ZnS 1020 (dec), 1185 (subl) Scheme 5 Category NH ₄ Br 462 (subl.) - - NH ₄ Cl 340 (subl.) - - NH ₄ F dec. - - NH ₄ I 551 (dec.) - -

The present invention will be described in more detail with reference to the following examples and comparative examples. However, the examples are only for illustrating the present invention and are not limited thereto.

EXAMPLE

Example 1

(Spherical Phosphor Prepared Using a Mixture of _Two Vapor Solvents (BiI ₃ , ZnI ₂ ))

17.5 kg of ZnS (manufactured by Sakai Co., Ltd.) in powder form was added 247.5 g of ZnS with 1% by weight of Cu, 157.5 g of ZnS with 1% by weight of Al, 3.375 g of BiI _{3 as a} gaseous flux, 3.375 g of ZnI ₂ , and 170 g of sulfur. Then, mixed for 15 hours in a V-mixer.

This mixture was filled with a third of a quartz crucible, the remainder was filled with a mixture of activated carbon and sulfur on the raw material mixture and covered with a lid, and then fired at 900 ° C. for 60 minutes in a kiln-type continuous furnace under a nitrogen atmosphere.

The resulting phosphor is spherical in shape, with color coordinates of x = 0.290 and y = 0.612. An electron micrograph after washing and dispersing this phosphor is shown in FIG.

Example 2

(Spherical Phosphor Prepared Using a Mixture of _Two Vapor Solvents (ZnI ₂ , ZnCl ₂ ))

To 19.5 kg of powdered ZnS (manufactured by Sakai Co., Ltd.), 260 g of ZnS with 1% by weight of Cu, 200 g of ZnS with 1% by weight of Al, 4.0 g of ZnI _{2 as a} gaseous flux, 10.0 g of ZnCl ₂ , and 400 g of sulfur were added. After the addition, the mixture was mixed for 15 hours in a V-mixer.

This mixture was filled with a third of a quartz crucible, the remainder was filled with a mixture of activated carbon and sulfur on the raw material mixture and covered with a lid, and then fired at 920 ° C. for 90 minutes in a kiln-type continuous furnace under a nitrogen atmosphere.

The resulting phosphor is spherical in shape and has color coordinates of x = 0.280 and y = 0.611. The electron microscope photograph of this fluorescent substance after water washing, dispersion | distribution, and surface treatment is shown in FIG.

Comparative Example 1

(Plate-shaped Phosphor Prepared Using One Liquid Membrane (MgCl ₂ ))

After adding 16.0 g of ZnS with 1% by weight of Cu, 10.0 g of ZnS with 1% by weight of Al, 15 g of MgCl _{2 as a} liquid flux, and 40 g of sulfur, were added to 974 g of powdered ZnS (manufactured by Sakai, Japan). Mix for 3 hours in a mixer.

This mixture was filled with a 2/3 quartz crucible, the remainder was filled with a mixture of activated carbon and sulfur on the raw material mixture and covered with a lid, and then fired at 900 ° C. for 60 minutes in a nitrogen atmosphere in a furnace.

The phosphor obtained therefrom is plate-shaped, and the color coordinates are x = 0.287 and y = 0.610. The electron microscope photograph after washing this fluorescent substance is shown in FIG.

Example 3

(Spherical Phosphor Prepared Using a Mixture of Two Vapor Solvents (BiI ₃ , SbI ₃ ))

To 974 g of powdered ZnS (manufactured by Sakai, Japan), 16.0 g of ZnS with 1% by weight of Cu, 10.0 g of ZnS with 1% by weight of Al, 0.3 g of BiI _{3 as a} vapor phase flux, 0.3 g of SbI ₃ , and 40.0 g of sulfur were added. After the addition, the mixture was mixed for 3 hours in a V-mixer.

The mixture was half filled in a quartz crucible, the remainder was filled with a mixture of activated carbon and sulfur on the raw material mixture, and the lid was closed, and then fired at 920 ° C. for 120 minutes under a nitrogen atmosphere.

The resulting phosphor is spherical in shape and has color coordinates of x = 0.286 and y = 0.615. The electron microscope photograph after washing this fluorescent substance is shown in FIG.

Comparative Example 2

(Plate-shaped phosphor prepared by mixing two kinds of vapor flux (BiI ₃ , SbI ₃ ) and one liquid flux (KI))

974 g of powdered ZnS (manufactured by Sakai Co., Ltd.), 16.0 g of ZnS with 1% by weight of Cu, 10.0 g of ZnS with 1% by weight of Al, 0.3 g of BiI _{3 as a} gas phase flux, 0.3 g of SbI ₃ , and KI 10 as a liquid flux g and 40 g of sulfur were added, followed by mixing for 3 hours in a V-mixer.

The mixture was half filled in a quartz crucible, the remainder was filled with a mixture of activated carbon and sulfur on the raw material mixture and covered with a lid, and then fired in a furnace at 920 ° C. for 120 minutes under nitrogen atmosphere.

The phosphor obtained therefrom is plate-shaped, and the color coordinates are x = 0.289 and y = 0.613. The electron micrograph after washing this fluorescent substance is shown in FIG.

Example 4

(Spherical Phosphor Prepared by Mixing ₃ Types of Gas Melting Agents (ZnCl ₂ , BiI ₃ , and SrBr ₂ · 6H ₂ O))

970 g of powdered ZnS (manufactured by Sakai Co., Ltd.), 5 g of ZnS with 1% by weight of Au, 15 g of ZnS with 1% by weight of Cu, 10.0 g of ZnS with 1% by weight of Al, and 0.15 g of ZnCl _{2 as a} gaseous flux, 0.15 g of BiI ₃ , 0.3 g of SrBr ₂ .6H ₂ O, and 15.0 g of sulfur were added, followed by mixing for 3 hours in a V-mixer.

The mixture was filled with a 2/3 quartz crucible, the remainder was filled with a mixture of activated carbon and sulfur on the raw material mixture, and the lid was capped, and then fired at 900 ° C. for 60 minutes under a nitrogen atmosphere.

The resulting phosphor is spherical in shape and has color coordinates of x = 0.299 and y = 0.603. The electron microscope photograph after washing this fluorescent substance is shown in FIG.

Comparative Example 3

(Spherical Phosphor Prepared Using Only One Type of Gas Melting Agent (SrI ₂ ))

After adding 13.0 g of ZnS with 1% by weight of Cu, 10.0 g of ZnS with 1% by weight of Al, 0.4 g of SrI _{2 as a} vapor phase flux, and 20.0 g of sulfur, were added to 970 g of powdered ZnS (manufactured by Sakai, Japan). Mix for 3 hours in a mixer.

The mixture was half filled in a quartz crucible, and the rest was filled with a mixture of activated carbon and sulfur on the raw material mixture, and then capped. Then, the temperature was raised in a quartz tube furnace under a nitrogen atmosphere at a temperature increase rate of 15 ° C./min, and 60 to 840 ° C. It was baked for a minute.

The resulting phosphor has a spherical shape but a non-uniform particle size and a color coordinate of x = 0.290 and y = 0.613.

The electron microscope photograph after washing this fluorescent substance is shown in FIG.

The spherical green phosphor prepared by the method of the present invention is manufactured into a phosphor powder as a final product through a process such as washing with water, attaching a pigment, and surface treatment, and mixing it with other compositions to prepare a composition for forming a fluorescent film and thus forming a cathode ray tube. And a fluorescent film on a flat panel display panel (TV CPT (color picture tube), computer monitor CDT (color display tube), thin CRT, FED, etc.).

The spherical green phosphors based on zinc sulfide produced by the production method of the present invention can improve luminance by improving the fillability of a flat panel display fluorescent film including a cathode ray tube.

Claims (7)

In the method for producing spherical green phosphors based on zinc sulfide by solid phase synthesis, a) iii) zinc sulfide; Ii) Cu-containing compound, or Au-containing compound as activator, Iii) Al-containing compounds as co-activators; Viii) sulfur; And Iii) two or more halogen-containing gas phase fluxes Mixing; And b) reducing the mixture obtained in step a) together with a mixture of sulfur and activated carbon Firing at a temperature of 800 to 1050 ° C. under an atmosphere Method for producing a zinc sulfide-based spherical green phosphor comprising a. The method of claim 1, Gas phase flux of step a) i) is BiCl ₃ , BiBr ₃ , BiI ₃ , CaBr ₂ , SbF ₃ , SbCl ₃ , SbBr ₃ , SbI ₃ , SnCl ₃ , SnCl ₄ , SnBr ₂ , SnBr ₄ , SnI ₂ , SnI ₄ , AlCl ₃ , AlBr ₃ , AlI ₃ , CuF ₂ , CuCl ₂ , GaF ₃ , GaCl ₃ , GaBr ₃ , GaI ₃ , MgI ₂ , SrBr ₂ , SrI ₂ , InCl ₃ , ZnCl ₂ , ZnBr ₂ , ZnCl ₂ , A method for producing a zinc sulfide-based spherical green phosphor selected from the group consisting of NH ₄ Cl, NH ₄ Br, and NH ₄ I. The method of claim 1, The gas phase flux of step a) iii) has a boiling point, a decomposition point, or a sublimation point below the reaction firing temperature, and the difference is 80 ° C. or more. The method of claim 1, The method of manufacturing a zinc sulfide-based spherical green phosphor of step a) comprises 0.01 to 0.3% by weight of a gas phase flux of i). The method of claim 1, Reducing atmosphere of step b) is a nitrogen atmosphere, or hydrogen atmosphere of a zinc sulfide-based spherical green phosphor manufacturing method Zinc sulfide-based spherical green phosphor prepared by the production method of claim 1. A cathode ray tube or a flat panel display panel using a fluorescent film of a zinc sulfide-based spherical green phosphor prepared by the method according to claim 1.