Phosphor consisting of hollow particles, phosphor slurry, phosphor beads for analysis using tracer technique and their production processes

Abstract

A phosphor consisting of hollow particles, each hollow particle having an outer shell and a space in the inside of said outer shell.

What is claimed is:  
     
         1 . A phosphor consisting of hollow particles, each hollow particle having an outer shell and a space in the inside of said outer shell.  
     
     
         2 . The phosphor consisting of hollow particles according to  claim 1 , wherein the space is present at the approximately center portion of each hollow particle.  
     
     
         3 . The phosphor consisting of hollow particles according to  claim 1 , wherein the volume of the space is at least 15 vol % of the volume of the entire hollow particle.  
     
     
         4 . The phosphor consisting of hollow particles according to  claim 1 , wherein the ratio of the maximum particle size to the minimum particle size of each hollow particle is from 1.0 to 1.2.  
     
     
         5 . The phosphor consisting of hollow particles according to  claim 1 , wherein at least part of the outer shell is made of one layer of crystallite.  
     
     
         6 . A phosphor slurry containing a plural types of phosphors having different emission colors, wherein among the phosphors, at least one phosphor having a large specific gravity is a phosphor consisting of hollow particles as defined in  claim 1 .  
     
     
         7 . A process for producing a phosphor consisting of hollow particles, which comprises spraying a solution containing metal elements constituting the phosphor into a carrier gas to obtain fine droplets, and drying the fine droplets to form hollow particles, followed by thermal decomposition.  
     
     
         8 . The process for producing a phosphor consisting of hollow particles according to  claim 7 , wherein formation of the hollow particles is carried out by adjusting the rate of drying the droplets so that the surface of the droplets maintains the critical concentration of supersaturation, and the center portion has a concentration lower than the equilibrium concentration of saturation.  
     
     
         9 . The process for producing a phosphor consisting of hollow particles according to  claim 7 , wherein the droplets are adjusted to have an average particle size of from 0.5 to 100 μm and dried at a temperature of from 100 to 400° C. for from 0.1 to 5 seconds to form the hollow particles.  
     
     
         10 . Phosphor beads for analysis using tracer technique to be used to determine an organic substance, a reactant which reacts with the organic substance, or a substance inhibiting the binding of the organic substance to the reactant, by utilizing the binding of the organic substance to the reactant, wherein either the organic substance or the reactant is fixed to a radioactive labeled compound and the other is fixed to the phosphor beads, said phosphor beads being spherical or substantially spherical hollow particles, each hollow particle having a median particle size of from 0.01 to 10 μm.  
     
     
         11 . The phosphor beads for analysis using tracer technique according to  claim 10 , wherein the ratio of the maximum particle size to the minimum particle size is from 1.0 to 1.2.  
     
     
         12 . The phosphor beads for analysis using tracer technique according to  claim 10 , wherein the volume of the hollow part in each hollow particle is from 15 to 85 vol % of the volume of the entire particle.  
     
     
         13 . The phosphor beads for analysis using tracer technique according to  claim 10 , which comprise a host material of a metal oxide.  
     
     
         14 . The phosphor beads for analysis using tracer technique according to  claim 13 , wherein the host material of a metal oxide is Y 2 O 3 .  
     
     
         15 . The phosphor beads for analysis using tracer technique according to  claim 13 , wherein activating ions are Eu 3+ .  
     
     
         16 . A process for producing the phosphor beads for analysis using tracer technique as defined in  claim 10 , which comprises spraying an aqueous solution containing raw materials for a phosphor into a carrier gas to obtain fine droplets, and drying the fine droplets in a gas flow to form particles, followed by thermal decomposition to produce hollow spherical or substantially spherical phosphor beads.  
     
     
         17 . Phosphor beads for analysis using tracer technique to be used to determine an organic substance, a reactant which reacts with the organic substance, or a substance inhibiting the binding of the organic substance to the reactant, by utilizing the binding of the organic substance to the reactant, wherein either the organic substance or the reactant is fixed to a radioactive labeled compound and the other is fixed to the phosphor beads, said phosphor beads being spherical or substantially spherical solid particles, each solid particle having a median particle size of from 0.01 to 8 μm.  
     
     
         18 . The phosphor beads for analysis using tracer technique according to  claim 17 , wherein the ratio of the maximum particle size to the minimum particle size is from 1.0 to 1.2.  
     
     
         19 . The phosphor beads for analysis using tracer technique according to  claim 17 , which comprise a host material of a metal oxide.  
     
     
         20 . The phosphor beads for analysis using tracer technique according to  claim 19 , wherein the host material of a metal oxide is Y 2 O 3 .  
     
     
         21 . The phosphor beads for analysis using tracer technique according to  claim 19 , wherein activating ions are Eu 3+ .  
     
     
         22 . A process for producing the phosphor beads for analysis using tracer technique as defined in  claim 17 , which comprises spraying an aqueous solution containing raw materials for a phosphor into a carrier gas to obtain fine droplets, and drying the fine droplets in a gas flow to form particles, followed by thermal decomposition to produce solid spherical or substantially spherical phosphor beads.