| 摘要 |
PURPOSE:To improve a recording density by executing recording, reproducing and erasing in both of guide grooves and land parts and to exactly execute access at a high speed by pit constitution for obtaining position information. CONSTITUTION:Tracks having M-pieces of the guide grooves of approximately the same size and the land parts of (M-1) pieces of lands between the guide grooves for an integer M of >=2 are composed. The substrate is subjected to recording, reproducing and erasing by condensing (2M-1) pieces of light beams to the individual guide grooves and the land parts. Since the pits for forming the address information are formed in the one or plural land parts within the tracks, the recording, reproducing and erasing are possible with a semiconductor laser of relatively low output if one beam among the plural light beams pass the pits. The recording, reproducing and erasing in M-pieces of the guide grooves and (M-1) pieces of the land parts are made possible and increasing of the recording density is possible. Further, the width of the guide grooves of the regions having the pits is formed narrower than in the regions where there are no pits so that the larger change in the reflected light quantity is obtd. at the time of passing of the light beams. The exact reproduction of the positional information from the pits is thus possible. |
