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:
Dec. 09, 2008
Filed:
Jul. 26, 2001
Richard A. A. Heylen, Leed, GB;
Richard A. A. Heylen, Leed, GB;
Macrovision Corporation, Santa Clara, CA (US);
Abstract
A method of copy protecting optical discs uses the differences in capability between the encoder associated with a laser beam recorder and that in currently available CD writers. Digital sum value (DSV) is a property of the encoded data on CDs and an encoder, which controls a laser beam recorder may be able to choose a pattern of merge bits which result in the overall DSV having optimal properties. During mastering of a CD, data patterns are added to the disc to provide an authenticating signature. These data patterns are chosen to cause DSV problems. Currently available CD writers have been found to have difficulty writing an authenticating signature of the type described without producing a resulting CD which has severe readability problems. Thus, the copy disc written by the CD writer will result in a CD reader returning corrupted data or information signalling a read error.