| 摘要 |
PROBLEM TO BE SOLVED: To provide the width of grooves adequate for stabilizing signal quality, the adequate ratio of the width of lands and the width of prepits and the adequate depths of the prepits and grooves in the case the prepits are formed on the lands between the adjacent grooves. SOLUTION: The grooves 2 for recording desired information are concentrically or spirally formed on a substrate 1 and the lands 3 are formed in contact with both sides in the width direction of the grooves 2. The prepits 4, 4,... recording the address information of the optical disk are formed on continuation with the grooves 2 on the lands 3. The width of the grooves 2 is 1/3 to 1/2 the diameter of the spot 6 of a laser scanning beam for irradiating the surfaces of the grooves 2. The ratio of the width of the prepits 4 to the width of the lands 3 is specified to 0.3 to 0.6. The depths of both of the prepits 4 and the grooves 2 are specified to 40 to 65 nm. |
