| 摘要 |
An optical disk according to the present invention includes: a substrate in a disk shape; guide grooves arranged at a pitch p in a radial direction of the substrate, each of the guide grooves being formed so as to extend in a circumferential direction of the substrate; and a pre-pit formed in a space between the guide grooves so as to extend along the guide groove. The optical disk is configured so that an address signal assigned to each location on a signal surface is indicated by the arrangement of the pre-pit in accordance with a predetermined rule. The pre-pit is composed of a pair of pre-pits formed on respective sides of the guide groove. The pair of pre-pits are arranged so as to be displaced in the circumferential direction so that a distance between inner edges of the respective pre-pits in the circumferential direction is smaller than the pitch p of the guide grooves. An optical disk apparatus of the present invention detects light reflected from the optical disk configured as above, calculates a differential phase detection signal, and detects an address signal using the differential phase detection signal. According to this optical disk apparatus, an address signal can be read reliably even at a region where a recording mark is formed so as to lie over the address pre-pit.
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