Optical recording medium having light transparent cover layer smaller in outer diameter than substrate

Abstract

An optical recording medium is an optical disk formed by bonding a substrate to a light transparent cover layer smaller in thickness than the substrate, and the optical disk includes one or more recording layer between the substrate and the light transparent cover layer. The light transparent cover layer is smaller in diameter than the substrate. Further, it is desirable that an outer edge of the substrate be higher than a between-edge part of the substrate. With this arrangement, a bonding surface of the substrate and the light transparent cover layer is not exposed out of an outer curved surface. Accordingly, it is possible to protect the bonding surface between the outer edge and the inner edge so as to increase strength against exfoliation of the light transparent cover layer.

Dependencies are inferred from the claim text.