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. 06, 1990
Filed:
Jul. 06, 1988
Applicant:
Inventors:
Wolfgang Pabst, Munich, DE;
Manfred Rehmet, Munich, DE;
Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01J / ;
U.S. Cl.
CPC ...
313632 ; 313633 ; 313311 ; 313336 ;
Abstract
To improve the arc stability of a high-pressure arc discharge lamp, typically a xenon arc lamp, the cathode (4) has an essentially conical end portion (9), terminating in a roughly flat, or slightly rounded tip (10). The cathode is covered with a carbide layer (11) decreasing in thickness towards the tip (10) and, preferably, leaving a zone (12) adjacent the tip and extending over about one-third of the end zone (9) free from carbide. The carbide has a lower melting temperature than the tungsten of the electrode, and leaving the tip free from carbide prevents deterioration of the electrode due to melting of the carbide material, in operation of the lamp.