| 摘要 |
PURPOSE:To obtain the information recording medium which is excellent in tracking in the outer peripheral part of a disk by forming the pregrooves existing on an outer peripheral side to the depth shallower than the depth of the pregrooves existing on the inner peripheral side than a reference circumferential position. CONSTITUTION:The pregrooves 4 within a region 7 on the outer peripheral side than the circumferential position of the circle having a diameter smaller by 10mm than the diameter of a substrate 1 of the information recording medium constituted by providing a dye recording layer 2 to allow information recording by a laser on the disk-shaped substrate which has a hole part 6 at the center and is provided with the pregrooves 3, 4 to a toric shape are formed to the depth shallower than the depth of the pregrooves 3 on the inner peripheral side. The recording layer 2 provided on the pregrooves 4 in the region 7 is formed to the layer thickness smaller than the layer thickness of the recording layer 2 provided on the pregrooves 3 on the inner peripheral side. The fluctuations in the push pull signals on the outer peripheral side are decreased in this way and, therefore, the optical disk allowing easy tracking control is obtd. |
