Koninklijke Philips Corporation N.V.

Sander Habets

Carsten Deppe

Christofher Daniel Charles Hooijer

Tom Munters

Hans Antonie Feijen

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.

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Berghem, Netherlands

Sander Habets