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:
May. 25, 1982
Filed:
Apr. 14, 1980
Applicant:
Inventors:
Bertus de Vrijer, Eindhoven, NL;
Leonard C Eijkelenboom, Eindhoven, NL;
Jan de Ridder, Eindhoven, NL;
Assignee:
U.S. Philips Corporation, New York, NY (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01J / ; H01K / ;
U.S. Cl.
CPC ...
313315 ; 313112 ; 313113 ;
Abstract
In the electric incandescent lamps having an infrared radiation-reflecting filter which is pervious to visible light, the efficiency can be increased by adapting the geometry of the filter and the geometry of the filament to each other. According to the invention, the filter comprises a major portion of a prolate ellipsoid of revolution and a cylindrical filament extends between the foci thereof, the distance between focal points being from 1-2 times the length of the filament.