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:
Jun. 30, 1992
Filed:
Dec. 21, 1990
Arunava Dutta, Chestnut Hill, MA (US);
Ernest A Dale, Hamilton, MA (US);
Leonard V Dullea, Peabody, MA (US);
GTE Products Corporation, Danvers, MA (US);
Abstract
A method has been found which reduces substantially the degradation of the red phosphor, Y.sub.2 O.sub.3 :Eu, in water base fluorescent lamp suspension, thereby prolonging the shelf life of triphosphor suspensions. The method of the invention comprises forming a protective coating around individual particles of europium-doped yttrium oxide phosphor to inhibit degradation of europium-doped yttrium oxide phosphor in a water base phosphor coating suspension, the protective coating comprising an inorganic material and being of sufficient thickness to prevent the europium-doped yttrium oxide phosphor from reacting with the coating suspension. A preferred coating material is gamma-alumina.