Compositions – Inorganic luminescent compositions – Compositions containing halogen; e.g. – halides and oxyhalides
Reexamination Certificate
2001-04-19
2003-09-30
Koslow, C. Melissa (Department: 1755)
Compositions
Inorganic luminescent compositions
Compositions containing halogen; e.g., halides and oxyhalides
C252S30140S, C252S30140P, C252S30140R, C252S30140H, C252S301500, C252S30160R, C252S30160S, C252S30160P, C252S30160F
Reexamination Certificate
active
06627113
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a phosphor suitable for formation of a fluorescent layer for e.g. a fluorescent lamp, a plasma display panel (PDP) or a vacuum fluorescent display (VFD), a phosphor slurry, phosphor beads used for analysis using tracer technique such as radioimmunoassay together with a radioactive labeled compound, and their production processes.
2. Discussion of Background
A phosphor to be used for a fluorescent lamp, PDP or VFD has been obtained, in the same manner as a phosphor to be used for a cathode ray tube (CRT) or for other applications, by mixing raw material powders, followed by heating in a baking container such as a crucible at a high temperature for a long period of time so that a solid reaction takes place to form a phosphor consisting of solid particles, which are pulverized by e.g. a ball mill to obtain a phosphor powder.
However, when a phosphor produced by the above method is used as a fluorescent layer for a device such as a fluorescent lamp, PDP or VFD, e.g. ultraviolet rays, vacuum ultraviolet rays or low voltage electron beam as an excitation source, having a weak penetrating power, can not excite the inside of the phosphor but excite the surface layer of the phosphor alone for light emission. Therefore, the region which contributes to the light emission is limited to the surface layer of the phosphor. Accordingly, the region which contributes to the light emission is an extremely limited surface layer alone in the phosphor used for the fluorescent layer, which increases the production cost of a device.
Further, in a case of a fluorescent layer for a three component type fluorescent lamp for example, a mixed phosphor slurry containing a plural types of phosphors having different emission colors is subjected to sedimentation coating method, and if there is a significant difference in specific gravity among the phosphors mixed, unevenness in composition may be caused due to difference in sedimentation rate during the coating, thus causing non-uniformity in the emission color.
Aside from this, a phosphor is used also in fields of medicine and industrial technology. Namely, in the fields of medicine and industrial technology, it is necessary to detect the presence of a small amount of an organic substance such as an antigen, an antibody, a hormone, a metabolic substrate, an enzyme or a medicine. Many biological analysis methods have been developed to detect a small amount of such an organic substance. Among them, a representative analysis method is analysis using tracer technique of detecting a binding of an organic substance to a reactant which biochemically specifically reacts with said organic substance, wherein a labeled compound (tracer) is fixed to either the organic substance or the reactant. Radioimmunoassay is a representative example thereof.
Radioimmunoassay utilizes a specific binding of an antibody (Ab) to a specific target antigen (Ag). To a mixture of an antigen (Ag) and a certain amount of an antigen (Ag*) having a labeled compound (tracer) fixed thereto, a certain amount of an antibody (Ab) is added, followed by incubation, and Ag-Ab (non-labeled bound complex) and Ag*-Ab (labeled bound complex) are formed due to an antigen-antibody reaction. Here, if the amount of the antibody (Ab) is made to be relatively small as compared with the amount of the antigen (Ag+Ag*), (Ag) and (Ag*) competitively bind to the antibody (Ab), and accordingly the proportion of the Ag-Ab (non-labeled bound complex) and Ag*-Ab (labeled bound complex) depends on the amount of (Ag). Here, the bound complexes and free (Ag*) are separated and the amount of the labeled compound (tracer) in the labeled bound complex (Ag*-Ab) is measured to determine the amount of the antigen (Ag) in an unknown sample from an analytical curve showing the relation between the amount of the labeled compound (tracer) and the amount of the antigen (Ag), preliminarily obtained by using a known amount of the antigen (Ag).
As the labeled compound (tracer) to be used in the above method, a radioactive isotope (RI) may be used, or RI and a fluorescent material may be used in combination. In a case where a radioactive isotope is used alone as a labeled compound, radiation from Ag*-Ab (labeled bound complex) are measured by using a radiation detector such as a scintillation counter.
Further, in a case where RI and a fluorescent material are used in combination as a labeled compound (tracer), RI is fixed to either the antigen (Ag) or the antibody (Ab), and the fluorescent material is fixed to the other, and fluorescence emitted from an antigen-antibody bound complex is measured by a photodetector such as a photomultiplier or a CCD camera.
The reaction proceeds in a liquid. The range of radiation from RI becomes shorter in a liquid, although it depends on the type of RI, and accordingly fluorescence can be detected when a fluorescent substance is present at a very short distance from RI. Namely, fluorescence from a bound complex of an antigen and an antibody can be detected, however, no fluorescence from a fluorescent substance fixed to an antigen or an antibody which is not combined with an antigen or an antibody labeled with RI can be detected even when the fluorescent substance receives radiation from RI in a liquid. Accordingly, it is not necessary to separate antigen-antibody bound complexes and an uncomplexed antigen or antibody, as in a conventional radioimmunoassay.
Here, a fluorescent material is usually produced by mixing phosphor raw material powders, putting the mixture into a baking container such as a crucible and heating it at a high temperature for a long period of time so that a solid reaction takes place, followed by pulverization into fine particles by e.g. a ball mill and classification to produce phosphor particles. In such a method, irregular particles in a form of sheets, columns or fragments and having an average particle size exceeding 2 &mgr;m are produced, and crude aggregated particles having a plurality of such particles aggregated are present in a considerable amount. Further, as such particles are solid particles, the specific gravity of the particles is the same as the true specific gravity of the phosphor and is rather large.
If such phosphor particles are used as phosphor beads for analysis using tracer technique, since the phosphor beads have irregular shapes, it tends to be difficult to uniformly coat the phosphor beads with an organic substance to be measured such as an antigen or antibody or its reactant in an adequate amount, and it also tends to be difficult to uniformly disperse the phosphor beads in the reaction system of e.g. an antigen or an antibody. Accordingly, a uniform reaction tends to be inhibited, which causes decrease in accuracy of analysis.
Further, in a case of carrying out a survey of new drugs by using many wells so that a plurality of samples to be measured are simultaneously reacted, such as in a High Throughput new drug Screening system, a slurry of phosphor beads having an organic substance to be measured or its reactant coated (fixed) thereon is preliminarily prepared, which is successively poured into a plurality of wells in a certain amount. For this pouring operation, a certain time is required. If the phosphor beads have a large specific gravity, the phosphor beads begin to sediment before a stirring operation is started after the completion of the pouring operation, and accordingly there may be a difference in the concentration of the phosphor beads among the plurality of wells, which may cause decrease in accuracy of measurement. To avoid this, it is required to carry out the pouring operation while stirring the liquid in the well, such being extremely troublesome. Further, while successively pouring the preliminarily prepared slurry of the phosphor beads into the plurality of wells, sedimentation of the phosphor beads takes place in the slurry, and there may be a difference in the content of the phosphor beads poured among samples even if the same amount of th
Kijima Naoto
Miwa Taiichiro
Kasei Optonix Ltd.
Koslow C. Melissa
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