The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 09, 1995
Filed:
Feb. 15, 1994
Yoshihiro Nishisu, Tsukuba, JP;
Mikio Kobayashi, Tsukuba, JP;
Abstract
A fluorescent material is disclosed which indludes substantially spherical particles each consisting of Y.sub.2 O.sub.3 and Eu.sub.2 O.sub.3 and having an average particle diameter of 90-210 nm and a narrow particle size distribution. The fluorescent material may be produced by heating an aqueous solution having a pH of 3 or less and containing a yttrium salt, a europium salt and urea at a temperature of at least 90.degree. C. to coprecipitate YOHCO.sub.3 and EuOHCO.sub.3 as particles having an average particle diameter of 110-270 nm. The resulting particles are then calcined at a temperature of at least 600.degree. C. to form spheres each consisting of Y.sub.2 O.sub.3 and Eu.sub.2 O.sub.3.