| 摘要 |
PROBLEM TO BE SOLVED: To easily discern a first layer and a second layer simply from a difference of polarities of address pits of a track error signal by making positions of two kinds of address pits to an information track different between the first layer and second layer. SOLUTION: A first address pit 303 and a second address pit 304 are arranged to positions shifted by half a pitch in a radial direction to a land track 302 and a groove track 301, respectively. The address pits 303 and address pits 304 are arranged so that a first positional relationship of the address pits 303 and address pits 304 in the radial direction is opposite to a second positional relationship of address pits 303 and address pits 304. The positional relationship of the first address pit 303 and the second address pit 304 is made different, so that polarities of the address pits appearing to a track error signal become different. A difference of a first layer and a second layer can be discerned accordingly. |
