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:
Nov. 17, 2009
Filed:
Dec. 16, 2004
Pavel Pekarski, Aachen, DE;
Jan Alfons Julia Stoffels, Turnhout, BE;
Holger Moench, Vaals, NL;
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
A method and a circuit arrangement for operating a discharge lamp, in particular during the first hours of operation after lamp manufacture, are described. The method and the circuit arrangement are provided in particular for high-pressure gas discharge lamps (HID or high intensity discharge lamps or UHP or ultra high performance lamps). Furthermore, a lighting unit with a discharge lamp and such a circuit arrangement and a projection system with a projection display and such a lighting unit are described. Switching-over between various modes of operation with different operating frequencies serves to avoid that the burning voltage of the lamp drops into a region of a minimum voltage of a lamp driver unit below which the latter can no longer drive the lamp with its rated power or a desired power.