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.
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