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:
Feb. 21, 1989
Filed:
Dec. 16, 1986
Applicant:
Inventors:
Philip J White, Georgetown, MA (US);
David A Goodman, Salem, MA (US);
Assignee:
GTE Products Corporation, Danvers, MA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J / ; H01J / ;
U.S. Cl.
CPC ...
313631 ; 313633 ; 313558 ;
Abstract
A high pressure sodium vapor discharge device including a polycrystalline alumina arc tube which contains a fill including sodium and mercury is disclosed. An electrode is disposed at each end of the arc tube, and an emissive material including an oxygen getter, such as, zirconium and/or niobium, and thorium dioxide is coated on at least one of the electrodes. The improved emissive material coating reduces the rate of sodium loss from the arc tube and inhibits loss of luminosity due to discoloration of the arc tube.