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. 10, 2012
Filed:
Jul. 08, 2008
Jens Pollmann-retsch, Aachen, DE;
John-john Pieter Jan Van Den Bergh, Turnhout, BE;
Uwe Mackens, Aachen, DE;
Pavel Pekarski, Aachen, BE;
Mark Carpaij, Aachen, DE;
Carsten Deppe, Aachen, DE;
Jens Pollmann-Retsch, Aachen, DE;
John-john Pieter Jan Van Den Bergh, Turnhout, BE;
Uwe Mackens, Aachen, DE;
Pavel Pekarski, Aachen, BE;
Mark Carpaij, Aachen, DE;
Carsten Deppe, Aachen, DE;
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
In this method an arc-length control value, indicating the current length of a discharge arc of the gas-discharge lamp (), is monitored and the lamp () is driven in a first operation mode (OMP) with a first current wave-shape when the arc-length control value indicates that the arc-length is higher than a switching threshold, which first current wave-shape is selected to result in a tip () growing on an electrode () of the lamp (), and the lamp () is driven in a second operation mode (OMn) with a second current wave-shape when the arc-length control value indicates that the arc-length is lower than a switching threshold, which second current wave-shape is selected such that the tip () on the electrode () is at least partly melted back. In this method an operating frequency of the lamp is switched from a first frequency value (fi) to a second frequency value (f), which second frequency • (f) value is higher than the first frequency value (fi)', if a first time criterion pertaining to a duration of driving of the lamp () in the second operation mode (OMn) is fulfilled and the operating frequency is switched from the second frequency value (f) to the first frequency value (fi), if a second time criterion pertaining to a duration of driving of the lamp () in the first operation mode (OMP) is fulfilled.