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:
Jun. 11, 2002
Filed:
Oct. 13, 1997
John O. Ryan, Cupertino, CA (US);
Kordian J. Kurowski, San Jose, CA (US);
Ronald Quan, Cupertino, CA (US);
Macrovision Corporation, Sunnyvale, CA (US);
Abstract
A VGA (or other component video signal) output, e.g. from a computer or DVD player, is protected so it is viewable on a VGA monitor. However, if the component video signal is converted to composite video (e.g. television) the resulting television picture is of substantially degraded quality, thereby inhibiting viewing and/or copying. This protects for instance copyrighted material in the VGA format from unauthorized use. The protection involves modifying the horizontal or vertical synchronization signals in the VGA video in such a way that there is no adverse affect on a typical VGA monitor. However, most or all VGA to television converters and/or television sets and VCR's suffer from loss of synchronization, resulting in an unviewable picture. Also, methods and circuits for defeating the copy protection are provided.