Projection system and method for operating a projection system to compensate for overshoot sequence
US7887196B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 21, 2006 |
| Grant date | Feb 15, 2011 |
| Priority date | — |
| Expiry date | Feb 5, 2028 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/00
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method for operating a projection system (1) is described, wherein a brightness level (B1, B2, B3, B4, B5, B6) 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 (2) of the projection system (1) is operated via a lamp driver with an essentially square-wave alternating current (IL) SO that an overshoot sequence (0), which occurs in the alternating current (IL) after a current zero crossing during operation of the high pressure discharge lamp (2), has a frequency so high that for each possible brightness level at least one full period (P) of the overshoot sequence (0) lies essentially within a light switch-on or switch-off phase (ts) following the zero crossing. A projection system (1) and a lamp driver (10) for a high pressure discharge lamp (2) in such a projection system (1) are also described.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.