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:
Sep. 01, 1998
Filed:
Feb. 27, 1996
Applicant:
Inventor:
Charles R Ragsdale, Newport Beach, CA (US);
Assignee:
Illumination Technology, Inc., Cypress, CA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01K / ; H01K / ; H01K / ;
U.S. Cl.
CPC ...
445 48 ; 445 41 ; 427111 ;
Abstract
Filaments having a thin exterior tungsten phosphide layer for use in incandescent lamps are made by exposing tungsten filaments to vapors of elemental phosphorous at approximately 675.degree. to 725.degree. C. in an evacuated vacuum furnace. The tungsten phosphide layer protects the filaments from oxidation while the lamps are manufactured, and decomposes to tungsten and phosphorous when the lamp is first energized by current. The resulting elemental phosphorous acts as a gettering agent.