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:
Dec. 19, 1989
Filed:
Apr. 24, 1989
Ramon L Yale, Towanda, PA (US);
GTE Products Corporation, Stamford, CT (US);
Abstract
A terbium activated gadolinium oxysulfide phosphor having a green/blue emission ratio of from about 0.7 to about 2.0 is disclosed. A process is disclosed for producing this phosphor which comprises forming a uniform mixture of gadolinium oxide, sulfur, alkali carbonate, alkali phosphate, terbium oxide, wherein the terbium oxide is provided in an amount sufficient to result in a terbium concentration of from about 0.25% to about 0.9% by weight, and a zinc compound wherein the zinc compound is provided in an amount sufficient to result in a zinc concentration of from about 0.05% to about 1.0% by weight, the zinc concentration and the terbium concentration resulting in the above ratio, the ratio increasing as the zinc concentration increases and as the terbium concentration increases, heating the mixture in an atmosphere in a covered vessel at a temperature of from about 900.degree. C. to about 1400.degree. C. for a sufficient time to form terbium-activated gadolinium oxysulfide, washing the terbium-activated gadolinium oxysulfide with deionized water to remove essentially all of any water soluble impurities which are present, annealing the resulting washed terbium-activated gadolinium oxysulfide in air at a temperature of from about 525.degree. C. to about 590.degree. C. for about 1 hour to about 3 hours to enhance the brightness of the phosphor.