JP2009215486A - Spherical phosphor particle, method for manufacturing the same, and resin composition and glass composition each containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spherical phosphor particle which has both of transparency, which is enough to form a transparent phosphor layer when sealed by a transparent resin or glass, and high packability, which is enough to keep the amount of a sealant low in durability to be used to a minimum, and excellent sphericity and to provide a method for manufacturing the spherical phosphor particle, and a resin composition and a glass composition each containing the spherical phosphor particle. <P>SOLUTION: The spherical phosphor particle contains A (A is one or more elements selected from Al, Ga, Ge, W, P, V, Zn, Si, B, Mg, Ca, Ba, Sr and Sc), Ln (Ln is one or more elements selected from Y, Gd, La, Sm, Dy, Ho, Er, Yb and Lu), O and R as an activator (R is one or more elements, which are selected from Eu, Tb, Ce, Sm, Tm, Pr, Nd, Dy, Ho, Er, Yb, Mn, Ti, Fe, Cr and Pb and are the elements other than the elements to be selected as Ln) being an activator as principal components and has an amorphous phase based on Ln, O and R being the activator as the principal phase and 1.0-1.1 average ratio of (the long side) to (the short side). <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to spherical phosphor particles having good translucency and filling properties, a method for producing the same, and a resin composition and a glass composition containing the spherical phosphor particles.

Phosphors used in displays such as cathode ray tubes and plasma displays, or fluorescent lamps, emit light when excited by an electron beam or ultraviolet light, and high luminous efficiency is obtained especially when the particle size is about several μm. ing. This type of phosphor is used by sealing particles having a size of several μm to several tens of μm with a resin having translucency. Since phosphor particles are often synthesized by a solid-phase reaction using a flux, the particle shape is an irregular polyhedron and a polycrystal. For this reason, phosphor particles may not be uniformly filled, resulting in unevenness in the phosphor layer, and it may be difficult to obtain uniform light emission. In addition, the filling rate of the phosphor particles can be increased. However, the content of the resin, which is easily deteriorated by excitation light and easily deteriorates in transparency, increases, and the durability of the fluorescent layer tends to deteriorate. For this reason, favorable spherical phosphor particles have been developed (Patent Documents 1 to 3).
Japanese Patent Publication No. 7-45655 Japanese Patent Laid-Open No. 11-43672 JP-A-8-109375

However, the phosphor particles described in Patent Document 1 are polycrystalline as described in, for example, Y ₃ Al ₅ O ₁₂ : Tb, and the phosphor particles described in Patent Document 2 include a plurality of single crystals. The phosphor particles described in Patent Document 3 are crystalline as described in the examples, and none of them is good in transparency.

  Therefore, the present invention has both transparency sufficient to form a transparent fluorescent layer when sealed with a transparent resin or glass, and high fillability capable of minimizing the use of a sealant with low durability. An object of the present invention is to provide spherical phosphor particles having a good spherical shape, a method for producing the same, a resin composition containing the same, and a glass composition.

  In order to achieve the above object, the present inventors have conducted intensive research, and as a result, the amorphous phase containing a specific element as a main component is used as a main phase, which is then sealed with a transparent resin or glass. It is possible to obtain spherical phosphor particles with good spherical shape that have both sufficient transparency to form a transparent fluorescent layer and high fillability that can minimize the use of a sealant with low durability. I found it. That is, the present invention relates to A (A is one or more elements of Al, Ga, Ge, W, P, V, Zn, Si, B, Mg, Ca, Ba, Sr, and Sc), Ln (Ln is Y, Gd, La, Sm, Dy, Ho, Er, Yb, and Lu), O, and R as an activator (R is Eu, Tb, Ce, Sm, Tm, Pr, Nd) , Dy, Ho, Er, Yb, Mn, Ti, Fe, Cr, and Pb, and an amorphous phase mainly composed of an element other than the element selected as Ln. Spherical phosphor particles having a phase ratio of 1.0 to 1.1 on average in the ratio of the long side to the short side.

  The present invention is also a method for producing spherical phosphor particles, comprising a step of obtaining spherical phosphor particles by cooling and solidifying the molten particles containing the main component to form the amorphous phase. Furthermore, the present invention is a resin composition and a glass composition containing the spherical phosphor particles.

As described above, according to the present invention, transparency sufficient to form a transparent fluorescent layer when sealed with a transparent resin or glass and the use of a sealant with low durability can be minimized. It is possible to provide spherical phosphor particles having a high spherical shape and a good spherical shape, a method for producing the same, and a resin composition and a glass composition containing the same.

  The spherical phosphor particles according to the present invention have an amorphous phase mainly composed of A, Ln, O and R as a main phase, and the crystal phase mainly composed of these is contained in the amorphous phase. The major axis of this crystalline phase is preferably 200 nm or less. If the major axis of the crystalline phase present in the amorphous phase is 200 nm or less, the backscattering of light is suppressed, and transparency is not impaired. Here, the major axis of the crystalline phase means the longest diameter when the crystalline phase is not a true sphere.

  In this way, the spherical phosphor particles in which the crystalline phase is present in the amorphous phase can be obtained by cooling and solidifying the molten particles containing the main component by adjusting the melting and solidifying conditions of the molten particles. Spherical particles that can be obtained by forming a solid phase, and that are obtained by cooling and solidifying the molten particles containing the main component to form an amorphous phase containing A, Ln, O, and R as main components. Then, spherical particles having the amorphous phase as the main phase are heated while adjusting the conditions to crystallize at least a part of the amorphous phase. The adjustment of the melting and solidification conditions of the molten particles when obtaining a crystalline phase present in the amorphous phase can be achieved by, for example, lowering the melting temperature or melting particles when the molten particles are introduced into the refrigerant. By lowering the temperature, it is easy to obtain a product in which the crystalline phase is present in the amorphous phase. On the other hand, in the case of a composition having a high melting point, a composition greatly deviating from the eutectic composition, etc., the amorphous phase can be obtained by increasing the temperature at the time of melting or the temperature of the molten particles when the molten particles are introduced into the refrigerant. It becomes easy to obtain what consists only of.

  In the spherical phosphor particles according to the present invention, A, Ln, O and R are the main components other than A, Ln, O and R as long as they do not hinder the non-crystallization of A, Ln, O and R. This means that a small amount of the above component may be contained, for example, A, Ln, O and R are 95% by weight or more. Furthermore, an amorphous phase as a main phase means that a crystalline phase may be contained in a very small amount. For example, it means that the amorphous phase is 70% by weight or more and is amorphous. The case where it consists only of a crystalline phase and the case where a crystalline phase exists in an amorphous phase are included.

  In the spherical phosphor particle according to the present invention, A may be any one or more of Al, Ga, Ge, W, P, V, Zn, Si, B, Mg, Ca, Ba, Sr and Sc. However, it is preferably one or more elements of Al, P, Si, Ga, and Sr. Ln may be any one or more of Y, Gd, La, Sm, Dy, Ho, Er, Yb, and Lu, but any one or more of Y, Gd, La, and Lu. It is preferable. R may be any element selected from Eu, Tb, Ce, Sm, Tm, Pr, Nd, Dy, Ho, Er, Yb, Mn, Ti, Fe, Cr, and Pb. Tb, Ce, Sm, Tm and Pr are preferred. When the above preferable elements are selected, it is easy to obtain spherical phosphor particles having good sphericity and exhibiting high luminance emission in the visible region. When Al is selected as A, spherical phosphor particles having a good sphericity and exhibiting high-luminance emission in the visible region are easily obtained.

  In the spherical phosphor particles according to the present invention, the long side refers to the longest diameter of the spherical particles, and the short side refers to the shortest diameter of the spherical particles. The ratio of the long side to the short side can be measured using, for example, a laser microscope. The spherical particles according to the present invention are obtained by measuring 50 spherical particles using a laser microscope and calculating an average value thereof. The spherical phosphor particles according to the present invention have an average ratio of long side to short side of 1.0 to 1.1. When the ratio of the long side to the short side is larger than 1.1, the filling property into the resin and glass having translucency is deteriorated, and good fluorescence cannot be obtained. The average particle diameter of the spherical phosphor particles according to the present invention is preferably 500 μm or less. When the thickness is larger than 500 μm, the filling property into the resin and the glass having translucency is deteriorated, and good fluorescence cannot be obtained.

  The method for producing spherical phosphor particles according to the present invention includes the step of obtaining the spherical phosphor particles by cooling and solidifying the molten particles containing the main component to form the amorphous phase as described above. The molten particles containing the main component are those in which the constituent components are spheroidized in a molten state. Such molten particles can be obtained, for example, by a flame method, an atomizing method, and a spin disk method, and particularly preferably by a flame method. The flame method is a method in which particles each consisting of a constituent component are passed through a high temperature region having a temperature equal to or higher than the melting point. For example, the prepared particles are put into a chemical flame or thermal plasma to be melted and melted. It is the method of obtaining the spherical particle of this. The atomization method is a method in which a raw material composed of constituent components is melted in a crucible or the like, and a melt is ejected from a discharge port opened in the crucible. The spin disk method is a method in which a melt is applied to a disk that rotates at high speed. It is the method of making it collide in the state which maintained the molten state.

  In the flame method, particles prepared by granulating powdery raw materials with a spray dryer, etc., and bulk materials obtained by sintering or melting and solidifying the raw materials are pulverized to use particles adjusted so as to obtain a desired particle size distribution. It is performed by putting the particles into a chemical flame or thermal plasma while suppressing the aggregation and melting them in the chemical flame or thermal plasma.

  In the flame method, a liquid precursor containing an element having a desired composition ratio such as a raw material colloidal liquid or an organometallic polymer can be used. It is carried out by spraying into plasma and evaporating the solvent or dispersion medium in a chemical flame or thermal plasma and then melting it. It is also possible to provide a low-temperature heating zone between the nozzle and the chemical flame or thermal plasma and evaporate the solvent or dispersion medium in the liquid raw material, and then put it into the chemical flame or thermal plasma.

  In the flame method, it is only necessary to obtain a high temperature of 2400 ° C. or higher as a generation source of the chemical flame. Used. In addition, oxygen, nitrogen, argon, carbon dioxide gas and mixed gas thereof, and water are used as a source of thermal plasma. When gas is used, an inductively coupled plasma apparatus is used, but water is used. It is preferred that

  In the case of the atomizing method or the spin disk method, the raw material may be any of powder, a molded body, a sintered body, and a solidified body, or a combination of two or more of these. These raw materials are accommodated in a crucible having a melting point higher than the melting point thereof, for example, a crucible made of Mo, W, Ta, Ir, Pt or the like, or a Cu crucible cooled by water or the like and then melted. The melting method may be any method as long as the raw material can be heated to a temperature equal to or higher than its melting point, and for example, high frequency, plasma, laser, electron beam, light, or infrared can be used. The raw material is preferably melted in an atmosphere in which the raw material is not evaporated or decomposed and the crucible is not significantly consumed. An optimum atmosphere is selected depending on the raw material and the material of the crucible used, such as in the air, in an inert gas, or in a vacuum.

  In the atomization method, spherical molten particles can be formed by ejecting a melt from pores opened in a crucible bottom or the like using gas pressure or the like. The spin disk method tilts the crucible, and in the same way as in the atomizing method, the melt collides with the rotating disk by, for example, jetting the melt from the pores opened at the bottom of the crucible using gas pressure etc. And spherical molten particles can be formed.

  As the molten particles containing the main component, these oxides are used as raw materials, but any oxides may be used as long as they are melted, and hydroxides, carbonates, and the like may be used. The composition ratio of these raw materials is preferably in the range of forming a eutectic composition and in the range of ± 10% by weight of the ratio. For example, when the composition of the spherical phosphor particles composed of Al, Y, O and Eu as an activator is within such a range, it is likely to become amorphous due to its relatively low melting point. This is because it becomes easy to obtain spherical phosphor particles having a good spherical shape.

  Next, the spherical molten particles are cooled to form an amorphous phase. This cooling step can be performed, for example, by putting the spherical molten particles into a refrigerant and rapidly solidifying them. The molten particles containing the main component can be solidified in a non-equilibrium state by rapid cooling with a liquid refrigerant, and the spherical particles are solidified in a state where the atomic structure at the time of melting is substantially maintained. In addition, it is easy to obtain spherical particles having extremely small solidification shrinkage and good spherical shape. In addition, by using quenching with a refrigerant, it is possible to suppress contact between particles before solidification and to form a good spherical shape. As the refrigerant, a non-flammable medium is preferable, and for example, helium gas, water, liquid nitrogen, liquid argon, or the like can be used. You may adjust the ratio of the long side of the spherical particle which consists of an obtained amorphous phase to a short side to 1.0-1.1 on an average. The amorphous spherical particles are solidified in a state in which the atomic structure at the time of melting is substantially maintained by quenching with a liquid refrigerant, and spherical particles having a very small solidification shrinkage and a good spherical shape can be obtained.

  Next, in the method for producing spherical phosphor particles according to the present invention, when obtaining the crystalline phase in the amorphous phase, the spherical phase containing the amorphous phase is heated to obtain the crystalline phase. A part thereof is crystallized by precipitating or improving crystallinity, and the heating temperature at this time is preferably 800 ° C. or higher, more preferably 1000 to 1700 ° C. By appropriately selecting the temperature, time, heating rate, etc. of the heat treatment, the structure can be controlled, and spherical particles having a structure suitable for the purpose can be produced. For example, in the case where the crystalline phase is precipitated or the crystallinity is improved by heating at a temperature close to the melting point, a large temperature rise is performed in order to prevent the crystalline phase from coarsening and maintaining a good spherical shape. The speed and short heating time are selected.

  The method for heating the spherical particles is not particularly limited as long as the spherical particles can be heated at a temperature of 800 ° C. or higher and the melting point or lower. Resistance heating, high frequency induction heating using a susceptor, laser heating, electron beam heating Any method such as light heating or infrared heating may be used.

  Generally, microspheres are stored in a crucible made of ceramics such as aluminum oxide or magnesium oxide or a high melting point metal such as molybdenum, tantalum, platinum, iridium, etc., and the microspheres are heated. A method of heating while moving in a tubular furnace made of the same material as the crucible provided with a temperature gradient and a soaking area, or a microsphere, the predetermined temperature gradient and soaking area provided A method of heating while dropping in a vertical tubular furnace made of the same material as the crucible is employed.

  The heat treatment of the spherical particles may be performed in any atmosphere, such as in the air, in an inert gas, in a reducing gas, in a hydrocarbon gas, or in a vacuum, but is limited by the crucible and heating method used. There is.

  Thereafter, if necessary, the spherical phosphor particles are washed or heat-treated to produce desired spherical phosphor particles. The cleaning is performed according to the purpose with an organic solvent such as acetone or isopropyl alcohol, or various acids. In addition, in the case of spherical phosphor particles having a composition that is easily reduced, heat treatment in the presence of oxygen may show better fluorescence. Therefore, heat treatment in air or oxygen is performed at a temperature of 400 ° C. or higher. To produce desired spherical phosphor particles.

  Next, a resin composition and a glass composition having translucency at least in the visible region containing the spherical phosphor particles according to the present invention, and methods for producing these will be described.

  Since the spherical phosphor particles according to the present invention have extremely good fluidity, they exhibit extremely good moldability when filled into a resin or glass. The obtained spherical phosphor particles can be classified by a sieve or the like so as to obtain a desired filling rate, and then subjected to surface treatment as necessary to further improve the filling rate. As the surface treatment agent, a silane coupling agent is generally used, but titanate and aluminate coupling agents can also be used.

  As the resin composition according to the present invention, a silicone resin and an epoxy resin can be used. However, the resin composition is not particularly limited as long as it has the fluidity required at the time of molding and does not devitrify significantly by light in a short time. . Moreover, a hardening | curing agent, a hardening accelerator, etc. are added as needed at the time of shaping | molding.

  As the glass composition according to the present invention, it is possible to use a composition having a melting point of 1000 ° C. or lower and does not significantly react with the spherical phosphor particles of the present invention at the molding temperature.

  The spherical phosphor particles, resin composition, and glass composition according to the present invention have translucency at least in the visible region.

Example 1
Next, Example 1 of the spherical phosphor particles according to the present invention will be described. Α-Al ₂ O ₃ powder, Y ₂ O ₃ powder and Tb ₄ O ₇ powder were used as raw materials. The α-Al ₂ O ₃ powder, Y ₂ O ₃ powder and Tb ₄ O ₇ powder are mixed by a wet ball mill using water at a ratio of 65.3: 29.3: 5.4 from the former in a weight ratio and sprayed. The slurry obtained using a drier was granulated and dried to obtain granular particles having an average particle diameter of 11 μm.

  Granular particles obtained in parallel to the jet direction of the mixed gas are supplied into the flame formed by the combustion of the mixed gas of oxygen and acetylene, and melted and spheroidized in the flame. The spherical phosphor particles according to Example 1 were obtained by introducing the molten particles into running water and allowing them to solidify.

  The obtained spherical phosphor particles according to Example 1 had an average particle size of 8 μm, and the ratio of the long side to the short side was 1.02 on average. Spherical phosphor particles according to Example 1 were obtained by analyzing X-ray diffraction using Cu-Kα rays, observation with a transmission electron microscope, and analysis of characteristic X-rays using a semiconductor X-ray detector installed in the transmission electron microscope. , O and Tb were found to be composed of an amorphous phase.

  The spherical phosphor particles according to Example 1 were washed with acetone and dried, and then sealed with a transparent silicone resin to produce a transparent molded product having a thickness of 0.4 mm, and the fluorescence spectrum was measured. FIG. 1 shows the fluorescence spectrum of this molded product when excited at an excitation wavelength of 380 nm.

  Moreover, after washing | cleaning and drying the spherical fluorescent substance particle which concerns on Example 1 with acetone, it sealed with transparent bismuth type | system | group glass, and produced the transparent molded product similar to the above, and when the fluorescence spectrum was measured, A fluorescence spectrum similar to 1 was obtained.

Example 2
Next, Example 2 of the spherical phosphor particles according to the present invention will be described. Example 1 except that the raw material composition was changed from α-Al ₂ O ₃ powder, Y ₂ O ₃ powder and Eu ₂ O ₃ powder to a ratio of 63.9: 22.3: 13.8 from the former by weight ratio. By the same method, spherical phosphor particles according to Example 2 were obtained.

  The spherical phosphor particles according to Example 2 had an average particle diameter of 8 μm, and the ratio of the long side to the short side was 1.02 on average. The spherical phosphor particles according to Example 2 are obtained by analyzing X-ray diffraction using Cu-Kα rays, observation with a transmission electron microscope, and analysis of characteristic X-rays with a semiconductor X-ray detector installed in the transmission electron microscope. It was found to be composed of an amorphous phase composed of O, O and Eu.

  The spherical phosphor particles according to Example 2 were washed with acetone, dried, heated in air at 800 ° C., and then sealed with a transparent silicone resin to produce a transparent molded product having a thickness of 0.4 mm. The fluorescence spectrum when excited at an excitation wavelength of 380 nm was measured, and the fluorescence spectrum diagram shown in FIG. 2 was obtained.

Example 3
Next, Example 3 of the spherical phosphor particles according to the present invention will be described. The spherical particles composed of the amorphous phase composed of Al, Y, O and Tb and the spherical particles composed of the amorphous phase composed of Al, Y, O and Eu obtained in Examples 1 and 2 were mixed. Then, it was sealed with a transparent silicone resin to produce a transparent molded product having a thickness of 0.4 mm. It was confirmed that this molded product exhibited white light emission by excitation with an excitation wavelength of 380 nm.

Comparative Example 1
As Comparative Example 1, spherical particles were obtained in the same manner as in Example 1 except that the molten particles were solidified in the air. The spherical particles according to Comparative Example 1 have an average particle size of 8 μm, X-ray diffraction using Cu-Kα rays, observation with a transmission electron microscope, and analysis of characteristic X-rays using a semiconductor X-ray detector installed in the transmission electron microscope. Thus, it was found that it was composed of Y ₃ Al ₅ O ₁₂ containing α-Al ₂ O ₃ and Tb.

  The spherical particles according to Comparative Example 1 were washed with acetone and dried, and then sealed with a transparent silicone resin and bismuth glass to produce transparent molded products having a thickness of 0.2 mm and 0.4 mm. No molded product could be obtained.

It is a figure which shows the fluorescence spectrum by the excitation wavelength of 380 nm of the spherical fluorescent substance particle obtained in Example 1. FIG. It is a figure which shows the fluorescence spectrum by the excitation wavelength of 380 nm of the spherical fluorescent substance particle obtained in Example 2. FIG.

Claims (7)

  A (A is Al, Ga, Ge, W, P, V, Zn, Si, B, Mg, Ca, Ba, Sr, and Sc), Ln (Ln is Y, Gd, La, One or more of Sm, Dy, Ho, Er, Yb, and Lu), O, and R as an activator (R is Eu, Tb, Ce, Sm, Tm, Pr, Nd, Dy, Ho, Er) , Yb, Mn, Ti, Fe, Cr, and Pb, and the main phase is an amorphous phase mainly composed of an element other than the element selected as Ln, Spherical phosphor particles having a short side ratio of 1.0 to 1.1 on average.   The spherical phosphor particles according to claim 1, wherein the amorphous particles are formed by cooling and solidifying the molten particles containing the main component.   3. The spherical phosphor particles according to claim 1, wherein a crystalline phase is present in the amorphous phase.   4. The spherical phosphor particles according to claim 3, wherein the major axis of the crystalline phase is 200 nm or less.   The method for producing spherical phosphor particles, comprising the step of obtaining the spherical phosphor particles according to claim 1 by cooling and solidifying the molten particles containing the main component to form the amorphous phase.   A resin composition containing the spherical phosphor particles according to claim 1.   A glass composition containing the spherical phosphor particles according to claim 1.

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