Patent ID: 7813257
Filing Date: 2010-10-12
Classification: G11B

Abstract:
1. An optical recording medium comprising: a substrate having a groove and plural pits formed and arranged dispersedly in a circumference direction thereon, wherein the groove is formed to have a U-shaped cross section which is shallower than a depth of the pits, said U-shaped cross section having an open end opposite a bottom including a flat area, the U-shaped cross section being separated by two opposing sides that taper inwardly, each opposing side having a first portion tapering at a first angle from the open end toward a transition point, and a second portion tapering at a second angle from the transition point toward the bottom, the second angle being smaller than the first angle, said two opposing sides being spaced apart by said bottom so as not to converge, and the groove of the optical recording medium has a ratio of a bottom width to an aperture width in the U-shaped groove to be set to 17% or more.