Record medium, its manufacturing method, mother disc for record medium, and its manufacturing method

摘要

Binary information previously recorded in an innermost rim side area is enabled to be stably reproduced. A record medium is formed by sequentially laminating a first information layer 2, an intermediate layer 3, a second information layer 4, and a cover layer 5 onto a substrate 1. First grooves are previously formed in the innermost rim area of the substrate 1. Second grooves are previously formed in an area where data is recorded. The first grooves are set to be shallower and narrower than the second grooves. Thus, such a situation that a BCA signal is modulated by diffraction due to the grooves can be reduced.