Optical disk including a barcode pattern formed by a laser using pulse width modulation
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United States of America Patent
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Mar 6, 2012
Grant Date -
N/A
app pub date -
Jun 25, 2002
filing date -
Nov 17, 1994
priority date (Note) -
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status (Latency Note)
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Abstract
An object of the present invention is to provide a marking forming apparatus, a method of forming a laser marking on an optical disk, a reproduction apparatus, an optical disk, and a method of manufacturing an optical disk, capable of providing a greatly improved copy prevention capability as compared to prior known construction. To achieve this object, in the optical disk of the invention, for example, a marking is formed by a laser on a reflective film of a disk holding data written thereon and at least position information of the marking or information concerning the position information is written on the disk in an encrypted form or with a digital signature appended thereto.
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