Title:
PASSIVE COMPENSATION OF FOCUS TRACKING UTILIZING WINDING AND CAPACITOR
Document Type and Number:
WIPO Patent Application WO2003090235
Kind Code:
A3
Abstract:
A video display apparatus includes a cathode ray tube and a high voltage transformer. The high voltage transformer incorporates a high voltage winding for producing an anode voltage in the cathode ray tube. The high voltage winding has a tap which provides a focus voltage for the electron gun assembly of the cathode ray tube. The transformer also includes a primary winding which is included in a resonant circuit. A third winding has a second portion that is wound to be closely coupled to the portion of the high voltage winding not associated with the generation of focus voltage. The third winding is coupled between the primary winding and a capacitor to produce a current that controls a variation of a ratio between the focus voltage and the anode voltage as a function of variation in a beam current in the cathode ray tube.
Inventors:
WILLIAMS KEVIN MICHAEL (US)
BOYER MICHAEL EDWARD (US)
BOYER MICHAEL EDWARD (US)
Application Number:
PCT/US2003/011893
Publication Date:
April 01, 2004
Filing Date:
April 15, 2003
Export Citation:
Assignee:
THOMSON LICENSING SA (US)
WILLIAMS KEVIN MICHAEL (US)
BOYER MICHAEL EDWARD (US)
WILLIAMS KEVIN MICHAEL (US)
BOYER MICHAEL EDWARD (US)
International Classes:
H04N3/26; (IPC1-7): H01J29/70
Foreign References:
| US6252361B1 | 2001-06-26 | |||
| US6256074B1 | 2001-07-03 | |||
| US4742270A | 1988-05-03 | |||
| US4645990A | 1987-02-24 |
Other References:
See also references of EP 1497845A4
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