Sanyo Electric Co., Ltd.

Kouichi Tada

Seiji Kajiyama

Kenji Torazawa

Youichi Tsuchiya

Mitutaka Yamaguti

A disk apparatus is for a disk, and a DVD-RW or a DVD+RW can be mounted as the disk. For example, a wobble signal is detected on the basis of a laser beam reflected by a recording surface of the disk. A CPU determines whether a cycle of the wobble signal (wobble cycle) is 32 times or 186 times as long as a data cycle on the basis of a detection result of a detecting circuit. Then, when the wobble cycle is 186 times as long as the data cycle, the disk kind is identified as the DVD-RW, and when the wobble cycle is 32 times as long as the data cycle, the disk kind is identified as the DVD+RW.

Disk kind identifying method and disk apparatus

Micro-pits or micro-pit strings, which are disabled precise copying by means of illegal copying described above and enable signals different from signals of a normal disc to be detected in case of failure in precise copying, are recorded in a copy protected area of an optical disc beforehand. A read unit checks the copy protected area and determines a loaded disc is legal disc or illegally copied disc. If illegal, reading is prohibitted.

Optical recording disc capable of preventing illegal copy

An illegal disc copying protection system which includes an optical disc with recorded information as a series of pits aligned to a track direction from the optical disc, a recording system which records information as a series of pits aligned to the track direction from the optical disc, and a reading system which reads information being recorded as a series of pits aligned to the track direction from the optical disc.

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Gifu, Japan

Kouichi Tada