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. 16, 1991
Filed:
Mar. 05, 1990
Harald L Witting, Burnt Hills, NY (US);
General Electric Company, Schenectady, NY (US);
Abstract
An electrodeless high intensity discharge lamp having an excitation coil disposed about an arc tube includes thermal apparatus for ensuring that a metal halide condensate forms a protective film on the portion of the arc tube which is nearest the plasma arc discharge during lamp operation. For a short, cylindrical arc tube, the thermal apparatus comprises a heat shield situated on the top and/or bottom thereof. In one embodiment, the bottom of the arc tube is concave to ensure that the condensate does not collect on the bottom of the arc tube. The excitation coil may be situated sufficiently close to the arc tube to ensure that enough heat is removed from the side wall of the arc tube to a heat sink so that the protective metal halide film forms on the inner surface of the arc tube wall. An outer glass envelope is preferably situated between the arc tube and the excitation coil, which envelope also functions to remove heat from the arc tube side wall.