Patent ID: 7924672

Claim:
A playing apparatus for playing an optical-disk recording medium including a substrate having main data recorded in the form of a combination of pits and lands on one side thereof and at least a reflective layer and cover layer stacked on the substrate and to which sub data is recorded in the form of marks so formed on the reflective layer by irradiating writing-power laser light to the reflective layer that the level of a reading signal will be raised at portions where the marks are formed but will be lowered at the mark-formed portions in an optical-disk recording medium produced by physically transcribing the substrate shape of the above optical-disk recording medium, the apparatus comprising: a reading signal generating means for generating the reading signal by detecting a return part, from the optical-disk recording medium, of reading-power laser light having been irradiated to the optical-disk recording medium; a sub data detecting means for detecting the level of the sub data on the basis of the result of sampling the reading signal generated by the reading signal generating means at a predetermined sampling point; and a judging means for judging, based on a result of determining whether the value of the sub data detected by the sub data detecting means has a correct polarity, whether the optical-disk recording medium is a authenticated disk, wherein the sub data includes identification information unique to each optical-disk recording medium and an error correction code for error correction of at least the identification information, the apparatus further comprising: a polarity inverting means for inverting the polarity of the value of the sub data detected by the sub data detecting means; an error correcting means for making error correction of the substantial data on the basis of the error correction code included in the sub data supplied from the polarity inverting means; and a sending means for sending specific information to an external device via a required network, the judging means being designed to determine, by determining whether the error correcting means has made the error correction accurately, whether the detected sub data value has a correct polarity, to thereby judge whether the optical-disk recording medium is a authenticated one, and to supply, in case the optical-disk recording medium has been judged not to be any authenticated one, the value of the sub data once inverted by the polarity inverting means to the inverting means, and then have the error correcting means retry the error correction, to thereby supply the identification information resulted from the retried error correction to the sending means; and the sending means sending the identification information supplied from the judging means as the specific information to the external device.