| 摘要 |
PROBLEM TO BE SOLVED: To reduce jitters and a block error rate by accurately reproducing recording marks which are formed in pre-grooves narrower than the diameter of a reproduction light spot. SOLUTION: The information recording medium has a light absorbing layer, a light reflecting layer, and a protecting layer on a substrate 1. The substrate 1 has pre-grooves 22 (22') spirally or concentrically on the surface. Prepits 21 are formed between adjacent pre-grooves 22 and 22' so that groove depth (c) is less than the groove depth (a) of the pre-grooves. Consequently, even when part of a pre-pit is included in a reproduction light spot together with a recording mark formed in a pre-groove, part of the pre-pit included in the reproduction light spot is prevented from being recognized as part of the recording mark, so that recording marks can properly be reproduced. |
