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. 07, 1991
Filed:
Apr. 24, 1989
Ramon L Yale, Towanda, PA (US);
GTE Products Corporation, Stamford, CT (US);
Abstract
A process is disclosed for making a rare-earth oxysulfide phosphor resistant to hydrolysis, which comprises forming a slurry of the phosphor in water, adding to the slurry, a zinc compound in an amount sufficient to result in a zinc ion concentration in the water of from about 0.01 molar to about 0.05 molar, separating the resulting zinc-treated phosphor from the liquid portion of the slurry, heating the zinc-treated phosphor in air at a temperature of from about 500.degree. C. to about 600.degree. C. for a sufficient time to enhance the brightness of the phosphor, and screening the resulting heated phosphor to remove non-luminescent material therefrom. The phosphor has a resistance to hydrolysis that is at least about 50% greater than phosphors produced without the zinc treatment.