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:
Jul. 14, 1981
Filed:
Dec. 03, 1979
Robert J Regan, Needham, MA (US);
Paul O Haugsjaa, Acton, MA (US);
GTE Laboratories Incorporated, Waltham, MA (US);
Abstract
A light source includes a high pressure discharge lamp and incandescent filaments which provide illumination during the warm-up and hot restart periods associated with the discharge lamp. A current regulator, which provides dc power to the discharge lamp, draws sufficient current through one filament to energize the filament only during discharge lamp warm-up. A second filament provides illumination during the period after the occurrence of a momentary power failure or power transient which is required by the discharge lamp to cool down to its maximum starting temperature. A bimetal switch permits current flow through the second filament when the discharge lamp is above the maximum starting temperature. An electronic switch permits current flow through the second filament when a current sensing resistor senses a lack of current through the discharge lamp.