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:
Feb. 15, 2011
Filed:
Apr. 21, 2006
Carsten Deppe, Aachen, DE;
Tom Munters, Hasselt, DE;
Christofher Daniel Charles Hooijer, Helmond, NL;
Hans Feijen, Eindhoven, NL;
Sander Habets, Berghem, NL;
Carsten Deppe, Aachen, DE;
Tom Munters, Hasselt, DE;
Christofher Daniel Charles Hooijer, Helmond, NL;
Hans Feijen, Eindhoven, NL;
Sander Habets, Berghem, NL;
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
A method for operating a projection system () is described, wherein a brightness level (B, B, B, B, B, B) in an image (IM) is represented by the total length of a number of light switch-on phases within a particular image cycle (VT). A high pressure discharge lamp () of the projection system () is operated via a lamp driver with an essentially square-wave alternating current (IL) SO that an overshoot sequence (), which occurs in the alternating current (IL) after a current zero crossing during operation of the high pressure discharge lamp (), has a frequency so high that for each possible brightness level at least one full period (P) of the overshoot sequence () lies essentially within a light switch-on or switch-off phase (ts) following the zero crossing. A projection system () and a lamp driver () for a high pressure discharge lamp () in such a projection system () are also described.