| 摘要 |
PROBLEM TO BE SOLVED: To provide an information recording medium which can obtain a good signal quality even when information is recorded at high density on an information track in the boundary part between zones. SOLUTION: An information recording medium is constituted in such a way that groove parts and flat parts are formed alternately on a transparent substrate, that both parts are used as tracks for information recording (groove-part information tracks 1 and flat-part information tracks 2), that nearly head parts of the tracks for information recording are provided with uneven-shape marks which can discriminate the groove parts or the flat parts even when they are formed in left positions or right positions with reference to the center of the tracks, that a plurality of information recording zones are provided and that information is recorded and reproduced in such a way that the tracks for information recording are irradiated with a light beam through the transparent substrate. In this case, address pit parts 3 to be used as discrimination marks are not formed in the boundary between the zones, and flat parts A in the boundary between the zones and both adjacent groove parts B, C are used as dummy tracks so as not to be used for a recording operation. |
