Patent ID: 7778143

Claim:
An optical disk comprising: 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 being configured so that an address signal assigned to each location on a signal surface is indicated by arrangement of the pre-pit in accordance with a predetermined rule, wherein the pre-pit for each of the grooves is composed of a pair of pre-pits formed on respective sides of the guide groove, each of the pair of pre-pits being independent from a pre-pit provided on opposing sides of an adjacent guide groove so as to represent the address signal different from the address signal assigned to the adjacent guide groove, and the pair of pre-pits are arranged so as to be displaced from each other 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.