PATENTSCOPE will be unavailable a few hours for maintenance reason on Tuesday 19.11.2019 at 4:00 PM CET
Search International and National Patent Collections
Some content of this application is unavailable at the moment.
If this situation persists, please contact us atFeedback&Contact
1. (WO2007004101) METHOD OF DRIVING A DISCHARGE LAMP IN A PROJECTION SYSTEM, AND DRIVING UNIT
Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

CLAIMS:

1. A method of driving a discharge lamp (1) in a projection system (10), wherein, in a feed-forward control process,
system status data (SDL, SDF, SDy) comprising
- static information pertaining to the design of the projection system and/or
- dynamic information pertaining to the projection system and/or
- dynamic information pertaining to the lamp operation
are obtained, and wherein,
based on the system status data (SDL, SDF, SDy),
- a momentary target light waveshape (LWT, LWT') required by the projection system (10) and
- a waveshape correcting function
are determined, and wherein
the actual current (I) of the discharge lamp (1) is regulated according to a momentary required waveshape (RW) which is determined based on the target light waveshape (LWT, LWT') and the waveshape correcting function.

2. The method according to claim 1, wherein the system status data (SDL) comprises data from the following data group:
lamp voltage (U), gas pressure of the lamp, electrode separation, electrode status, discharge arc attachment over time.

3. The method according to claim 1 or claim 2, wherein the system status data (SDv) comprises information from the following group of variable system settings: positive and negative pulse timing, light level (RL) and colour band

(CB), allowed place for anti-flutter pulse.

4. The method according to any of claims 1 to 3, wherein the system status data (SDF) comprises information from the following group of fixed system settings:
lamp type, reflector type, colour filter and/or modulator construction data, system etendue (SE).

5. The method according to any of claims 1 to 4, wherein
at least parts of a waveshape correcting function are generated by an interpolation between experimentally observed correcting sampling values (ks).

6. The method according to any of claims 1 to 5, wherein
a required lamp current (It) at a certain time (t) is calculated from the target light waveshape by means of a correcting factor (ks, kn, kP).

7. The method according to claim 6, wherein,
a correcting factor (kn) is calculated by the waveshape correcting function.

8. The method according to any of claims 1 to 7, wherein
certain correcting factors (ks,kn) or at least parts of a waveshape correcting function depending on certain system status data are stored in a look-up-table (LUT).

9. The method according to any of claims 1 to 8, wherein the correcting factors (ks, kn) and/or at least parts of the waveshape correcting function are determined depending on the following system status parameter:
- colour band (CB),
- required relative current or light level (RL),
- lamp voltage (U),
- system etendue (SE).

10. The method according to any of claims 1 to 9, wherein
at least parts of the waveshape correcting function and/or correcting factors (kp) depend on a number of time constants (τpl, τei) describing the physical behaviour of the discharge process.

11. A driving unit (11) for driving a discharge lamp (1) in a projection system (10) in a feedforward control process, which driving unit comprises
- a source (35, 38, 39) of system status data (SDL, SDF, SDV), which system status data (SDL, SDF, SDy) comprise
- static information pertaining to the design of the projection system and/or
- dynamic information pertaining to the projection system and/or
- dynamic information pertaining to the lamp operation;
- a pattern calculation unit (33) for determination of
- a momentary target light waveshape (LWT, LWT') required by the projection system (10) and
- a lamp current correcting function
based on the system status data (SDL, SDF, SDV); and
- a current control unit (34) for regulating the actual current (I) of the discharge lamp (1) according to a momentary required waveshape (RW) which is determined based on the target light waveshape (LWT, LWTO ^d the correcting function.

12. A driving unit according to claim 11 , wherein
the source (35, 38, 39) of system status data (SDL, SDF, SDy) comprises

- a lamp information unit (35) for obtaining data (SDL) pertaining the momentary status of the lamp (1);
- a first storage mean (38) comprising fixed setting data (SDF) of the projection system (10);
- a second storage mean (39) comprising variable setting data of the projection system.

13. A projector system, comprising a high pressure discharge lamp (1) and a driving unit (11) according to claim 10 or claim 11.