WO2006067863A1 - 電子線励起蛍光体とその製造方法 - Google Patents
電子線励起蛍光体とその製造方法 Download PDFInfo
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- WO2006067863A1 WO2006067863A1 PCT/JP2004/019747 JP2004019747W WO2006067863A1 WO 2006067863 A1 WO2006067863 A1 WO 2006067863A1 JP 2004019747 W JP2004019747 W JP 2004019747W WO 2006067863 A1 WO2006067863 A1 WO 2006067863A1
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- crucible
- phosphor powder
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- zinc
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G9/00—Compounds of zinc
- C01G9/08—Sulfides
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
Definitions
- Electron beam excited phosphor and method for producing the same
- the present invention is an electron beam tube (power sword ray tube: C
- Phosphor powder constituting the phosphor film used in FED more specifically, zinc sulfide phosphor particles that produce blue and green light emission required to display a high-quality image on the phosphor film
- the present invention relates to a child crystal and a manufacturing method thereof.
- electron beam tubes have the following advantages over liquid crystal display devices and plasma display devices.
- the energy conversion efficiency of the fluorescent film into visible light is as high as 20%, which does not allow other display devices to follow.
- High energy conversion efficiency and picture elements of the phosphor film are imaged with a dot-sequential scanning electron beam to display an image with a brightness similar to that of a daytime scene at a temperature rise of around 3 ° C. Can do.
- the electron tube has a very long life and low lifetime cost.
- the manufacturing cost itself is low.
- the total amount of energy consumed at the time of manufacturing the electron tube is much smaller than that at the time of manufacturing liquid crystal display devices and plasma display devices, and can meet social demands to reduce environmental pollution.
- the main technical problem for improvement of electron beam tubes and the like is to eliminate the flickering force that appears on the phosphor screen.
- the ellipse sways slightly due to the characteristics of the fluorescent film that irradiates the electron beam.
- the phosphor film is made up of a stack of phosphor particles, and each phosphor particle is an insulator. The fluorescent fine particles irradiated with the electron beam are charged. 7
- this charge / discharge of the capacitor intervenes in the local electric closed circuit of the fluorescent film, and disturbs the electron beam trajectory irradiating the fluorescent film, resulting in a small fluctuation of the local light emission of the fluorescent film. all right. This fact has been overlooked so far.
- the particle surface is clean.
- the function of the micro-capacitor of the phosphor particles is counteracted by the anodic electric field applied to the black matrix imparted with electrical conductivity under the fluorescent film.
- the small image fluctuation disappears from the fluorescent film. That is, the problem of flickering force on the electron beam screen can be solved by arranging phosphor particles with clean particle surfaces in two or less layers. Due to this lack of reasoning, the surface of the phosphor powder particles currently on the market remains heavily contaminated.
- the zinc sulfide phosphor powder manufactured by the manufacturing method of R CA has the following problems. It can be classified into (1) related to the emission center inside the particle and (2) related to the outside of the particle such as particle shape and size and surface. Problems with the former include phosphor brightness and emission color. When impure ions intervene in the zinc sulfide crystal lattice, brightness and emission color change. Problems caused by the latter include (i) the change in pH value and electrical conductivity of the PVA phosphor slurry coating solution over time, (mouth) the formation of a large number of fine particle forces S on the coated phosphor film, C) It is difficult to control the pattern by applying phosphor powder.
- the present inventor reexamined the manufacturing method of the ZnS phosphor from a basic level.
- molten N a C 1 acts as a flux in the growth of ZnS fine particles, but the present inventor applied various fluxes to the quartz tube.
- the fluxing effect of NaCl was not observed, and it was found that the aerated zinc halide had a fluxing effect.
- ZnCl 2 The function of zinc halides as a flux can be represented by ZnCl 2 , so the following explanation will proceed based on this, but the flux is not limited to ZnCl 2 . Because of its deliquescent nature, ZnCl 2 is an unsuitable material that requires accuracy of the order of 100 ppm in the weighing of raw materials. The inventor found the following facts. Sulfur in the molten state is very active and readily reacts with other compounds. If sulfur, metal chloride, or amorphous ZnS powder is placed in a crucible and the crucible is maintained at a temperature above the melting point of sulfur and below the boiling point, for example, 400 ° C, a chemical reaction between the molten sulfur and a small amount of chloride occurs.
- the phosphor powder according to the present invention as described above was cut off from the external world in the phosphor that emits light by electron beam excitation: Crystals with gaseous halogenated zinc as a flux within t ⁇ ⁇ It is characterized by being a fine crystal of zinc sulfide grown.
- the gaseous zinc halide is preferably vaporizable zinc chloride.
- the gaseous zinc halide is preferably gaseous zinc iodide.
- the gaseous halogen zinc can be appropriately implemented by being a gaseous odor zinc.
- These phosphor powders of the present invention preferably contain flat anchor particles that prevent the phosphor particles from flowing.
- the tabular anchor particles can be appropriately carried out by containing particles of 2 microns or less and a maximum of 10% by weight.
- the method for producing the phosphor powder of the present invention is characterized in that, in a crucible cut off from the outside, vaporized zinc halide is used as a flux, and zinc sulfide fine crystal is grown on the flux. To do.
- the phosphor powder production method of the present invention includes an amorphous zinc sulfide, sulfur, a non-alloyed metal compound, and an activator serving as an optical center in a crucible that is shielded from the outside world.
- the raw material mixture is filled with water and heated, and the crucible is held in the melting zone of the sulfur to increase the filling density of the mixture with molten sulfur, and at the same time the molten sulfur and non-alloyed metal Zinc halide is produced in the mixture by a chemical reaction of the halide, the subsequent temperature rise of the crucible is controlled, and oxygen contained in the mixture is converted into sulfur dioxide by the molten sulfur gas, and then the halogen Zinc fluoride is used as a flux, and in the mixed powder having a temperature gradient, zinc sulfide fine crystal is grown on the flux.
- the concentration of the zinc halide is preferably 100 to 3000 ppm with respect to 1 mol of zinc sulfide.
- the metal element of the non-alkali metal halide is magnesium or aluminum. Nyum is preferred! /.
- the cavity in the mixture can be appropriately implemented by being a space in which the halogenated dumbbell which has been relieved due to difficulty functions as a flux.
- the raw material mixture is weighted from above the raw material mixture in the crucible, and the raw material mixture is isolated from the space formed between the surface of the raw material mixture in which sulfur has melted and contracted and the inner wall of the crucible. It is possible to appropriately carry out by growing the fine crystals of dumbbell sulfide while keeping the range in which the halogenated zinc is effective as a flux within the contracted raw material mixture.
- the crucible was covered with a plate to ensure airtightness during the growth of ZnS particles, and to keep the ZnCl 2 vapor necessary for the growth of ZnS particles in the crucible. Based on. The amount of ZnCl 2 held by the crucible must be at least the minimum necessary for the flux.
- the necessary minimum amount of ZnCl 2 required for growing ZnS particles is about 500 ppm with respect to 1 mol of the raw amorphous ZnS powder.
- the amount of all bubbles in the filled mixture with ZnCl 2 vapor is around 100 ppm. Since the airtightness of the crucible can be adjusted by the weight of the lid, the lid should be of a weight that can hold ZnCl 2 vapor in the crucible above the minimum required amount.
- the growth of ZnS particles occurs in a local space (hereinafter referred to as a cavity) made of air bubbles inevitably generated in the mixture filled in the crucible, and is contained in the cavity. Proceed with absolute amount of ZnCl 2 vapor.
- the ZnCl 2 vapor pressure in the crucible is uniquely determined by the weight of the lid.
- the ZnCl 2 vapor pressure in the cavity in the crucible is constant, and the growing ZnS particle size is the size of the cavity. It depends on the size. Therefore, in order to obtain a ZnS phosphor having a uniform shape and particle diameter, it is effective that a cavity having a uniform diameter exists in the mixture heated in the growth temperature range of ZnS particles.
- One of the features of the present invention is the method of creating a uniform diameter cavity in the heated mixture.
- the mixture powder is filled in a crucible, approximately 60% of the volume of the filled mixture is air bubbles, and the size and shape of the bubbles are widely distributed.
- ZnS particles are grown without controlling the bubble size, and the obtained ZnS fine particle crystals have very different shapes and sizes as shown in the micrograph shown in FIG.
- the crucible filled with the phosphor raw material mixture is maintained at a temperature not lower than the melting point of sulfur and not higher than the boiling point, molten sulfur diffuses into the mixture and fills only the large cavities, but the surface tension is large. Does not enter. As a result, the volume of the mixture shrinks, and a mixture in which cavities of uniform diameter are uniformly distributed is obtained in the crucible. As a result, as shown in the micrograph in FIG. 2, a powder composed of ZnS fine particles with uniform shape and small variation in size is obtained.
- the size of the cavity obtained by using molten sulfur is smaller than desired.
- the average size of ZnS particles grown in a small cavity is around 2 microns, and the size does not change even if the molten sulfur conditions are changed.
- the average particle size of practical ZnS phosphors is around 4 microns. Therefore, in order to change the cavity diameter to an arbitrary size, an appropriate amount of water is added to the raw material powder when the raw material powder is mixed. This mixture is sufficiently stirred and mixed, and then filled into a bowl. When the crucible is heated, water vapor is generated in the mixture. 7 Vapor is held in a cavity that is weakly sealed by molten sulfur after molten sulfur fills the large cavity.
- the size of the cavity can be adjusted by the amount of water to be added and the program from room temperature to a region where molten sulfur is diffused.
- a fluorescent powder composed of ZnS fine particle crystals of a desired size (for example, 4 microns).
- Figure 3 shows a scanning electron microscope (SEM) photograph of the actual example.
- the oxygen contamination source of the ZnS phosphor is bubbles (cavities) in the mixed powder filled in the crucible. According to the inventor's research, the problem of oxygen contamination can be solved by detoxifying the oxygen in the cavity. The operation of removing oxygen and detoxifying the oxygen is effective when applied before ZnS crystal nuclei are generated in the mixture.
- the temperature at which ZnS crystal nuclei are generated from the ZnS raw material in the mixed powder is around 600 ° C. Therefore, harmful oxygen can be removed from the cavity at temperatures below 600 ° C. It is preferable to convert oxygen in the bubbles into a gas that is harmless to the light emission of the phosphor in the temperature range below 600 ° C, and to remove most of the converted gas from the cavity.
- the crucible filled with the raw material mixture is heated from room temperature to 400 ° C. and kept at that temperature for a predetermined time. With this heating, the molten sulfur is uniformly distributed in the mixture.
- This sulfur vapor is highly reactive and reacts with oxygen in the cavities to form a non-oxidized sulfur (SO2) gas that is harmless to the ZnS phosphor.
- SO2 gas generated in thermal expansion during temperature rise, diffuses into the crucible space from the cavity in the mixture. The SO 2 gas increases pressure in the crucible space, pushes up the crucible lid, and escapes out of the crucible. It is necessary to adjust the heating rate so that the thermally expanding SO 2 gas does not break through the cavity during this temperature increase.
- the problem of oxygen contamination is 600. Force generated in a calorie temperature range of C or higher With the method of the present invention, the problem of oxygen contamination can be solved without increasing the particle size when the temperature is increased from 400 ° C to 600 ° C, and light emission is achieved. ZnS phosphor powder with no variation in intensity and emission color can be produced with good reproducibility.
- the manufacturing method of the ZnS phosphor powder of the present invention is based on the fact that the ZnS phosphor is grown by the fluxing action of ZnCl 2 gas in an airtight space having a temperature difference. This is the conventional manufacturing method. And fundamentally different. In addition, this discovery makes it possible to create a temperature-raising program based on an understanding of the chemistry and physics that occurs in a calorie-heated mixture when the crucible is filled with raw material mixture powder. Details of the present invention will be described below. The invention's effect
- the phosphor powder of the present invention does not change the emission color even when used at high luminance, and can be used as a blue and green high-performance fluorescent powder for electron-excited phosphor films. Furthermore, when this Doko powder is used, it is possible to apply a homogeneous fluorescent film with a particle arrangement of about two layers, and the small size that appears in the image on the electron tube fluorescent film screen, which has been considered difficult in the past. The problem of fluctuation can be solved.
- the production method of the present invention can bring about significant progress in production technology as follows. (1) Without using sodium salt, which is a source of contamination of ZnS phosphor powder, as raw materials, it is possible to select halides from which various by-products can be easily removed as raw materials. (2) Good properties: By using soot, the amount of halide used can be significantly reduced to one-sixth of the conventional sodium salt content. (3) The generated zinc sulfide particles are in a weakly sintered state, and the removal of residual by-products becomes easy.
- Figure 1 is a photomicrograph (transmission) of commercially available blue ZnS: Ag: Cl phosphor particles.
- Figure 2 shows a micrograph of blue ZnS: Ag: Cl phosphor particles produced by the production method of the present invention. (Transmission).
- FIG. 3 is a scanning electron micrograph of blue ZnS: Ag: Cl phosphor particles having an average particle diameter of 4 ′ microns prepared by the production method of the present invention.
- Fig. 4 is a schematic diagram of a crucible with good airtightness in which the mixture powder is closely packed.
- FIG. 5 is a diagram showing a heating program for the crucible filled with the mixture powder for the blue phosphor.
- FIG. 6 is a photomicrograph (transmission) of the phosphor film of the present invention coated on a glass substrate in one layer by the number of particles.
- FIG. 7 is a scanning electron micrograph of a cross section of a commercially available phosphor (A) and a phosphor (B) of the present invention coated on a glass substrate.
- FIG. 8 is a diagram showing a heating program for the crucible filled with the mixture powder for the green phosphor. Explanation of symbols
- Embodiments relating to a method for producing ZnS phosphor powder that emits blue and green light suitable for a screen of an electron beam excitation display device according to the present invention will be described below in detail with reference to the drawings.
- ⁇ S In the production of the ZnS phosphor of the present invention, since air-tight zinc chloride is used, an airtight and crucible is used. The airtightness of the crucible can be obtained by smooth polishing of the lid and the upper surface of the crucible where it transects and the plate surface of the lid. The ring must be of a material that does not react with by-products generated from the mixture at high temperatures! / ⁇ . Commercial alumina crucibles using electronic grade materials can meet this requirement. In the following, the force to explain about using an alumina crucible The present invention is not limited to an aluminum crucible, and other materials such as a quartz crucible may be used.
- any chloride can be used in principle as long as it reacts with molten sulfur in the mixture to produce ZnCl 2 during the heat. The same result is obtained.
- the first is the melting point of sulfites produced by chemical reactions with sulfur.
- the melting point of sulfide is the melting point of sulfide.
- the melting point of the sulfide is 1000 ° C or less, the surface of the phosphor particle on which the sulfide melt film is grown is covered.
- the sulfide melt film covering the particle surface at high temperature solidifies at room temperature and sinters the phosphor particles hard. It is difficult to remove sulfide from this sintered body, and this is one of the sources of problems with conventional phosphor powders.
- the second item to consider is the solubility of the by-product sulfide in water. If the sulfide is soluble in water or dilute acid, the sulfide can be chemically removed from the phosphor powder. Many sulfides do not dissolve in water. In addition, if there is a large difference in the mass or particle size of the reaction product, it can be physically separated. This is simpler. That is, even if the sulfide is not dissolved in water or dilute acid solution, if the particle size of the sulfide is extremely small, 1 micron (or submicron), these fine particles are caused by vibration of water molecules in the water washing process. Suspended in water without sinking due to Brownian motion. Submicron particles are separated from phosphor powder when removing the supernatant of cleaning liquid 14 2004/019747 Yes.
- A1C1 3 of 0.1 mm or more larger particles as a raw material, the size of A1C1 3 particles are transferred to the byproducts A1 2 S 3 of large particles are formed.
- the size of A1C1 3 particles is not a problem for the formation of ZnCl 2 .
- a powder containing phosphor particles is suspended in water and the suspension is poured onto a 100-mesh sieve, the phosphor particles pass through the sieve, but the large particles A1 2 S 3 are placed on the sieve. The rest can be separated from the phosphor powder. Therefore, aluminum chloride can be used as a salt raw material.
- a gastight crucible using a polished lid when excess gas is generated in the crucible, the lid is pushed up by the vapor pressure of the gas, and the excess gas escapes out of the crucible. Temperature below 60 ° C Gas that is unnecessary for the growth of phosphor particles in the region is removed from the mixture, and it is 600.
- the ZnCl 2 vapor pressure required for phosphor particle growth in the ⁇ region above C is controlled by the weight of the lid. If the amount of ZnCl 2 required for the growth of ZnS particles is held in the crucible, it will be good.
- the minimum amount of ZnCl 2 gas held in the crucible is about 500 ppm with respect to 1 mol of ZnS based on the experimental results of the sealed quartz tube by the inventors. Assuming that all the cavities where ZnS particles grow are filled, it is 1000 ppm. Therefore, when using a highly airtight crucible and crucible, the concentration of chloride added during the preparation of the ZnS material is reduced from 500 ppm to 1000 ppm, which is 60 to 30 times lower than that of the conventional NaCl (several percent). it can. However, the airtightness of the crucible varies to some extent, so the amount of chloride added must be adjusted in the range of 300 to 3000 ppm. Preferred results are that the amount of chloride ranges from 400 to 2000 ppm, with the most preferred amount being around 600 to 1000 ppm.
- the raw material mixture powder composed of amorphous zinc sulfide, sulfur, a non-alkali metal halide and an activator serving as a luminescent center has a bulk density of about 0.5 g / cm 3.
- the atmosphere in the crucible is filled with a gas generated by the chemical reaction of the mixture. Gas generation continues until it reaches the mixture power S heat town. gas During the generation, the pressure in the crucible is higher than the pressure in the furnace, so it is difficult to be affected by the atmosphere in the furnace. Therefore, it is not necessary to artificially replace the air in the furnace with nitrogen gas or the like. Also, there is no need to place activated carbon powder on the filled mixture.
- Figure 4 shows the schematic diagram. 1 is a crucible, 2 is a crucible lid, 3 is a mixture contracted in the crucible, and 4 is an alumina plate on the contracted mixture.
- the alumina plate can be replaced with a quartz plate. Even if the crucible 1 with the anoremina plate 4 placed on the mixture is heated to around 970 ° C, the size of the cavity created in the mixture 3 remains unchanged. The shape of the phosphor crystallites grown in the cavity is uniform and the particle diameter is almost uniform.
- the atmosphere in the crucible is controlled by the heating program of the furnace that heats the crucible.
- the present inventor designed the heating program shown in FIG. 5 after elucidating the chemical reaction and physical phenomenon of the raw material mixture filled in the crucible.
- the Karo fever program can be roughly divided into three stages: A, B, and C. According to Fig. 5, the conditions necessary for heating the crucible and the crucible and the reasons are described in detail.
- step A5 of Fig. 5 the physical phenomenon of melting and diffusion of sulfur in the mixture is used to distribute sulfur uniformly in the raw material mixture powder at the molecular level.
- the mixture in the crucible is placed in a furnace below 100 ° C and heated up to 400 ° C.
- the effect of the heating rate is small, and if the holding time at 400 ° C is 30 minutes or more, there will be no sudden expansion of bubbles in the mixture.
- the large bubbles contained in the mixture filled in the crucible with a bulk density of around 0.5 g / cm 3 are filled with molten sulfur, leaving small bubbles of uniform diameter inside.
- the volume of the mixture shrinks to around 60% before the calorific heat.
- the amount of shrinkage is not sensitive to the amount of added sulfur, and the sulfur can be varied between 0.1 and 5 grams per 100 grams of raw ZnS powder. Preferred results are obtained in the range of 0.5 to 2 grams. Most preferred, the result should be around 1 gram.
- the packing density of the raw material mixture will be constant with no differences between individuals and every day, and the reproducibility of the particle size of the ZnS phosphor will be good.
- Another important role played by heating in this region A is the formation of ZnCl 2 by high-temperature chemical reaction between the molten sulfur and the chlorides in the mixture. The generated ZnCl 2 melts in this region and becomes a mixed solution with sulfur, and is uniformly distributed in the mixture.
- region A heating is the control of the cavity size. Control of the size of the cavity in the mixture is realized by the action of water added to the mixture. Water vapor is retained in the cavity whose volume is reduced by the action of the molten sulfur. Water vapor filling the cavity expands rapidly at a certain temperature, and the expansion pressure expands the cavity, so that a moderately sized cavity can be created in the mixture.
- the amount of water added is between 0.1 gram and 10 gram, preferably between 0.5 gram and 3 gram per 100 gram of raw ZnS powder.
- Optimal water volume is 1g Before and after. Into a mixture containing water; TO from room temperature to 400. Heating up to C in 30 minutes yields ZnS phosphors with particle sizes around 4 microns in the final stage of the Calorie program (see Figure 3).
- the preferred heating rate is 3 ⁇ 1 per minute.
- C. Detoxification of oxygen is 600. Increase the temperature to C. After raising the temperature to 600 ° C and holding for 30 minutes, the distribution of molten ZnCl 2 becomes uniform. At the same time, most of the gas unnecessary for ZnS particle growth goes out of the crucible.
- the heating rate is 8 ° C / min or higher, the evaporation of ZnCl 2 is rapid, and the ZnCl 2 gas in the cavity rapidly escapes out of the crucible.
- the heating rate is 2 ° C or less per minute, the gradient in the mixture is small, the growth of ZnS particles is slowed, and the particles are small.
- the optimum heating rate is 1 ° C for 6 soils per minute.
- the temperature in the mixture at 970 ° C is the temperature; the time it depends on the capacity of the crucible used is 90 minutes in many crucibles. ZnS particles grow in an agffi ed mixture? 19 19747 No.
- the obtained ZnS phosphor powder cleans the phosphor particle surface by adopting the same water washing process as before.
- the phosphor powder according to the present invention is weakly sintered with a small amount of ZnCl 2, and phosphor particle powder having a clean surface can be obtained much more easily than before.
- a simple description of the 7J washing process is as follows. Put the ZnS phosphor weakly sintered with ZnCl 2 in deionized (DI) water and leave it for 30 minutes. After that, when water is stirred, the phosphor particles are suspended in water. When this suspension is poured onto a 150 mesh screen, the phosphor particles pass through the screen. The phosphor particles that have passed through the sieve contain small bonded particle lumps, and these particle lumps are separated into individual particles by a ball mill using glass spheres.
- DI deionized
- the separated phosphor powder is washed repeatedly with ion exchange water.
- the main by-product that remains in the phosphor powder is the power of ZnCl 2
- the amount is very small and can be completely removed by washing with water. Repeating the wash until no chlorine can be detected in the supernatant liquid, the other by-products can be removed.
- the phosphor powder separated from water is dried. Put the dried phosphor powder in a 400 mesh sieve The phosphor powder that has passed through this becomes the phosphor powder produced by the method of the present invention. This phosphor powder
- Figure 6 shows a micrograph (transmission) of an example of such a fluorescent film.
- the fluorescent film is Cg until the particles suspended in the coating film settle on the substrate, the precipitated particles adhere to the substrate and do not move easily.
- a phosphor film as shown in Fig. 6 is formed.
- phosphor particles that adhere strongly to the substrate against the water flow are required.
- Such an insulator is a tabular grain having a flat crystal growth surface.
- the tabular grains move slightly, the particles strongly adhere to the substrate through the water and do not move. That is, the flat particles act as anchors ( ⁇ ) for the water flow. Other particles approaching the anchor are prevented from moving by the anchor. Therefore, if the distribution of anchor particles is appropriate, large pinholes cannot be formed.
- the anchor fluorescent film is made of three layers or less, the coating film is thin, so the amount of water is small and particles staying around the anchor do not accumulate.
- anchor particle force S is included in the phosphor powder.
- the anchor particles are slightly larger than the primary particles, as shown in the micrograph in Figure 6. Mu is preferred. As shown in Figure 1, extremely large particles can cause problems during application.
- a suitable amount of anchor particles is in the range of 1 to 15% by weight, preferably 5 to 10% by weight.
- An anchor particle cannot be produced by a method for producing zinc sulfide in which a raw material mixture is filled in a crucible. Before the particles grow, seed particles and amorphous zinc sulfide must coexist in the cavity. Furthermore, it was found that when an appropriate amount of polycrystalline microparticles serving as seed particles was mixed with amorphous zinc sulfide powder as a raw material, the number of anchor particles corresponding to the number of seed particles mixed grew.
- FIG. 2 shown above is a photomicrograph of a phosphor garlic containing an anchor particle produced by the method described above.
- the emission center consists of a pair of silver (Ag) and chlorine (C1), and is expressed as ZnS: A g : Cl in the formula.
- the concentration of the luminescent center is expressed as a molar ratio to ZnS and is lOO ppm. This concentration does not change.
- the blue ZnS phosphor powder manufacturing method according to the present invention is characterized by the fact that ZnCl 2 flux for growing ZnS particles is made of other chlorides instead of conventional NaCl, and the addition of the chlorides. The amount is less than 50 times that of conventional NaCl.
- Table 1 shows the composition ratio of the raw material mixed powder according to the present invention. In this example, hexahydrate magnesium chloride (MgCl 3 -63 ⁇ 40) is used as the added chloride. table 1
- a mixing time of 10 minutes or more is sufficient.
- the crucible 1 is filled with the mixed powder at a density of about 0.5 g / cm 3 .
- the ⁇ in the furnace is heated according to the temperature raising program shown in Fig. 5. Cool down to room temperature in the furnace after calorific heat. When the cooled crucible is removed from the furnace and the lid is removed, there is white powder in the crucible. This powder is a blue light-emitting ZnS: A g : Cl phosphor powder that is weakly sintered by solidification of a small amount of ZnCl 2 .
- a small amount of Mg by-product can be removed by washing with 0.1 N acid solution.
- the phosphor powder is then washed with DI water until no chlorine is detected from the supernatant. This cleaning can remove a small amount of ZnCl 2 .
- the phosphor powder after the washing process is separated from the water and dried by drying at 110 ° C.
- Blue phosphor ZnS: Ag: Cl phosphor powder can be obtained by classifying the dried phosphor powder with a sieve of 400 mesh or more.
- the PVA phosphor slurry liquid made using the above phosphor has a very good stability force S and a slurry. The characteristics of do not change. Therefore, if the above phosphor is used, a fluorescent film having an average of about two layers in terms of the number of particles can be applied.
- FIG. 6 A SEM photograph of the cross section of the phosphor film in which the commercially available phosphor powder (A) and the phosphor powder (B) of the present invention are applied to a glass substrate is shown in Fig. 6.
- the advantage of the phosphor powder coating film according to the present invention is clear.
- Fig. 7 (B) since the phosphor layer is thin, the flicker seen on the screen of the color electron beam tube can be ignored at clear distances.
- Blue light-emitting ZnS: Ag: Cl phosphor powder can also be produced by using hexahydrate aluminum chloride (A1C1 3 -6H 2 0) as a raw material salt of ZnCl 2 .
- Table 2 shows the mixing ratio of raw materials when ⁇ 3 ⁇ 4 ⁇ 6 ⁇ 20 is used. This, A1C1 3 .6H 2 0 Ca particle size is very small ⁇ , or large A1C1 3 using the .6H 2 0. With small A1C1 3 .6H 2 0, A1 2 S 3 -products, since the suspended without sedimentation in the wash water in, Torinozokeru with cleaning time of the supernatant.
- Aluminum salt is used as the raw material for ZnCl 2 : ⁇ , if oxygen is present when the raw material mixture is heated, the aluminum salt is easily oxidized to form aluminum oxide (A1 2 0 3 ).
- A1 2 0 3 aluminum oxide
- [alpha] 1 2 Omicron 3 is very stable compound, without reacting with sulfur in the presence of molten sulfur, the state of the A1 2 0 3 to hold.
- the temperature at which the aluminum salt is oxidized is 400 ° C or higher. Therefore, it is good if it can be converted to A1 2 S 3 before the aluminum salt in the mixture powder is oxidized.
- A1C1 3 is converted to A1 2 S 3 in the temperature range below 400 ° C.
- the oxygen contained in the mixed powder in the temperature range from 400 ° C to 600 ° C is easily converted and consumed by SO 2 by reaction with sulfur vapor, so the formed A1 2 S 3 is 970 ° C It is not oxidized even at high temperatures.
- the aluminum salt is not oxidized and is maintained in a sulfide state.
- the phosphor powder for which the calo heat program has been completed can be removed from the phosphor powder by the same processing steps as in Example 1. The resulting phosphor powder has the same characteristics as in Example 1.
- the green light-emitting ZnS phosphor is composed of copper (Cu) and aluminum (A1) as recombination emission centers.
- the formula is ZnS: Cu: Al.
- the emission center is different, the phosphor particle shape and size required for use in a display device and the surface state of the particle are the same as the blue phosphor.
- the major difference from the blue phosphor at the time of manufacture is that the phosphor is extremely reluctant to contaminate with chlorine.
- the luminance and emission color of the phosphor powder do not change due to chlorine contamination, a significant difference appears in the afterglow, and even a slight chlorine contamination shows a long-lived afterglow.
- ZnCl 2 vapor is suitable as a flux.
- Usable fluxes are Znl 2 or ZnBr 2 vapor. Either can be used. The following description is not limited to forces S, Znl 2 taking Znl 2 flux as an example.
- Table 2 ZnS: Ag: is replaced by A1C1 3 .6H 2 0 was used in the Cl blue phosphor in A1I 3 .6H 2 0, the mixing ratio of the raw material preparation is the same as Table 2 of.
- Table 3 shows the raw material mixing ratio of ZnS: Cu: Al 1 ⁇ 2 phosphor.
- the boiling point of Znl 2 is very different from ZnCl 2 .
- the melting point of Znl 2 is 446 ° C and 624. Do it with C. Growth of ZnS particles, since the proceeds in flux action of Znl 2 gas, it is necessary to close attention to the handling of Znl 2 gas.
- Fig. 8 shows the heating program necessary to produce a ZnS: Cu: Al green phosphor.
- stage A 8 of this program has already been explained in Examples 1 and 2.
- Retention of stage B 9 ⁇ t is the melting point of Znl 2 446. Must be higher than C and lower than 624 ° C, set between 500 ° C and 550 ° C. This is as described in Examples 1 and 2 for the C stage 10.
- the green light-emitting ZnS: Cu: Al phosphor produced according to the temperature program shown in Fig. 8 using a highly airtight crucible is weakly sintered.
- Weakly sintered green phosphor powder Karoe the same process as that described in Example 1 and 2], and dried, the surface contamination without luminance rises number 0/0 compared with the conventional brightness
- Rere ZnS: Cu: Al green phosphor powder can be produced.
- the problems that occur when using conventional green phosphor powder are solved by using the green phosphor powder produced by the method of the present invention.
- the phosphor powder containing the anchor particles is manufactured as follows.
- the phosphor powder used as seed particles is described as an example of a blue-emitting ZnS phosphor.
- Table 4 shows the raw material mixing ratio of the seed particles according to the present invention. Fill the mixed powder ingredients: Wi l. Place aluminum plate 4 on top of the filling mixture and cap with lid 2.
- This crucible is put in a furnace at room temperature and heated according to the temperature raising program shown in FIG. At that time, set the maximum temperature to 900 ° C. Cool to room temperature and remove the crucible from the furnace. ⁇ ⁇ Put the powder in the crucible into DI water and leave it for a while, then stir the water for 30 minutes using a stirrer. If the particles settle, remove the supernatant, add fresh DI water and stir again to remove the supernatant. After repeating this operation several times, the water and powder are separated and the powder is dried. When the dried powder is classified with a 20 mesh sieve, the powder that has passed through the sieve becomes the seed powder for the anchor particles.
- This seed powder is used and mixed with the raw materials at the mixing ratio shown in Table 5.
- this mixture is treated in the same steps as described in Example 1 and dried, a phosphor powder containing anchor particles is obtained. If this blue phosphor powder is used to make a phosphor film, the thin phosphor film shown in Fig. 6 and Fig. 7 (B) can be applied.
- the phosphor film falls off the substrate in the development process of photolithography when using phosphor powder containing only one anchor particle.
- the phosphor powder In order to obtain a phosphor film to be attached to the substrate, the phosphor powder must contain an appropriate amount of fine particles that form crater-shaped pinholes.
- the seed particles can be used for the fine particles used here.
- the above-mentioned seed particles are mixed with the finished phosphor powder at a ratio of 3 to 10% by weight, and the phosphor powder to which the seed particles are added is mechanically mixed for 30 minutes or more using a mixer.
- a blue phosphor film that adheres to a substrate even with a thick phosphor film can be produced.
- the phosphor powder of the present invention constitutes a phosphor film of an electron beam tube or an electric field irradiation type display device. Particularly suitable for blue and luminescent phosphor powders. Furthermore, when the phosphor powder of the present invention is used, the phosphor film can be applied in a particle arrangement of about two layers, and the problem of small fluctuations appearing in the image on the phosphor film screen, which has been difficult to solve in the past. Etc. The impact on the display device industry is significant.
- the production method of the present invention it is based on the discovery that the growth of sulfur sulfide and fine insulator crystals uses a fluorinated halogen dumbbell as a flux.
- This makes it possible to (1) select haguchigenides that can easily remove by-products from haguchigenides other than sodium salts, and (2) use halogen crucibles with good airtightness. (3) eliminates the sintering problem of the zinc sulfide phosphor to be produced, and (4) eliminates the problem of sintering of the conventional phosphor. By removing residual by-products that caused problems during use, (5) It becomes possible to produce phosphor powder with high brightness and no variation in emission color.
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Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH03275791A (ja) * | 1990-03-27 | 1991-12-06 | Kasei Optonix Co Ltd | 硫化物系蛍光体 |
JPH0445192A (ja) * | 1990-06-12 | 1992-02-14 | Mitsubishi Materials Corp | 板状硫化亜鉛螢光粉末の製造方法 |
JPH0641528A (ja) * | 1992-07-21 | 1994-02-15 | Miyota Kk | 白色発光蛍光膜を持つ陰極線管 |
JP2001329261A (ja) * | 2000-05-10 | 2001-11-27 | Samsung Sdi Co Ltd | 低駆動電圧で高効率発光する硫化亜鉛系蛍光体の製造方法 |
JP2003253260A (ja) * | 2002-03-04 | 2003-09-10 | Kasei Optonix Co Ltd | 硫化亜鉛蛍光体 |
-
2004
- 2004-12-24 WO PCT/JP2004/019747 patent/WO2006067863A1/ja not_active Application Discontinuation
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH03275791A (ja) * | 1990-03-27 | 1991-12-06 | Kasei Optonix Co Ltd | 硫化物系蛍光体 |
JPH0445192A (ja) * | 1990-06-12 | 1992-02-14 | Mitsubishi Materials Corp | 板状硫化亜鉛螢光粉末の製造方法 |
JPH0641528A (ja) * | 1992-07-21 | 1994-02-15 | Miyota Kk | 白色発光蛍光膜を持つ陰極線管 |
JP2001329261A (ja) * | 2000-05-10 | 2001-11-27 | Samsung Sdi Co Ltd | 低駆動電圧で高効率発光する硫化亜鉛系蛍光体の製造方法 |
JP2003253260A (ja) * | 2002-03-04 | 2003-09-10 | Kasei Optonix Co Ltd | 硫化亜鉛蛍光体 |
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