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:
Mar. 29, 1977
Filed:
May. 19, 1975
Paul V Kelsey, Jr, Blacksburg, VA (US);
James E Mathers, Ulster, PA (US);
GTE Sylvania Incorporated, Stamford, CT (US);
Abstract
Phosphors having the general formula (A.sub.1.sub.-x RE.sub.x).sub.2 Hf.sub.2 O.sub.7 are disclosed wherein A is selected from the group consisting of yttrium, gadolium, lanthanum, scandium and lutetium; RE is selected from the group consisting of praseodymium, samarium, europium, terbium, dysprosium, holmium, erbium and thulium; and x is from about 0.001 to 0.10. The phosphors are prepared by dissolving an oxide of A and an oxide of RE in a mineral acid and dissolving HfOCl.sub.2 in water and combining the two solutions. A precipitating agent such as oxalic acid is added and the precipitate is washed, dried and fired to produce the phosphors.