发明名称 CDROM copy protection
摘要 A method of forming an optical disc, and an optical disc formed, so as to facilitate identifying unauthorized copies of the disc by using a defined procedure for reading the disc. The method comprises the steps of encoding digital data, comprised of a series of 0s and 1s, in the disc by forming a series of spaced pits along a track, so that the track comprises a series of pits and lands, and wherein, when said defined procedure is used to read the disc, each of said pits and lands is read as either a 0 or a 1. The method comprises the further step of forming at least one fuzzy area on the track so that when the defined procedure is used to read the disc, the fuzzy area is sometimes read as 0 and sometimes read as 1. With a preferred procedure, the pits reflect a given light beam at a first intensity, the lands reflect the given light at a second intensity, and the fuzzy area reflects the given light at a third intensity substantially midway between the first and second intensities.
申请公布号 US6767695(B2) 申请公布日期 2004.07.27
申请号 US20010764836 申请日期 2001.01.17
申请人 INTERNATIONAL BUSINESS MACHINES CORPORATION 发明人 KELLEY EDWARD E.;MOTIKA ERIC M.;MOTIKA FRANCO;MOTIKA PAUL V.
分类号 G11B7/24;G11B7/004;G11B7/005;G11B7/007;G11B7/013;G11B19/12;G11B20/00;G11B20/10;G11B23/28;(IPC1-7):G11B7/00 主分类号 G11B7/24
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