High recording density optical disc

Abstract

The present invention provides an optical disc of the land/groove method having equivalent optical characteristics for the land and the groove, serving as an optimal optical disc for the land/groove recording. A groove formed on a substrate 2 has a greater value than a width of a land of the substrate 2. The groove formed on the substrate 2 has an average width Wg defined by the following Equation (1). 0.46Tp+2Δ≦Wg≦0.54Tp+2Δ  (1) wherein Δ=(Tg To)/tan θ; Tg represents a film thickness of the recording layer formed on a slanting portion of said groove formed on said substrate; To represents a film thickness of said recording layer formed on a flat portion of said groove formed on said substrate; θ represents an angle defined by said slanting portion and said flat portion of said groove formed on said substrate; and Tp represents a sum of the average width Wg of said groove and the average width W1 of said land formed on said substrate.

Dependencies are inferred from the claim text.