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:
Aug. 21, 1990
Filed:
Dec. 07, 1988
Edmund M Passmore, Gloucester, MA (US);
Robert J Karlotski, Weare, NH (US);
Simone P Bazin, Bedford, NH (US);
GTE Products Corporation, Danvers, MA (US);
Abstract
A metal halide discharge lamp includes an arc tube having a chemical fill, and a pair of electrodes sealed in the arc tube. The electrodes are tungsten and have differing thoria contents. The electrodes with differing thoria contents provide faster starting times than electrodes with equal low thoria contents and eliminate the electrode meltback, voltage increase and lumen loss that is characteristic of electrodes with equal but higher thoria contents. Preferably, one electrode has a thoria content of about 1.5 to 2 weight percent, and the other electrode has a thoria content of about one weight percent or less.