Patent ID: 6128273
Filing Date: 2000-10-03
Classification: G11B

Abstract:
An optical disk, comprising:a substrate having a groove configured to guide a light beam and having a land, said groove having a wobble in accordance with a modulation signal and having a depth between 25 nm and 200 nm;a lower protective layer overlying said substrate and having a thickness between 10 nm and 200 nm;a rewritable recording layer on said lower protective layer and comprising a phase-change material; andan upper protective layer on said rewritable recording layer and having a thickness between 10 nm and 60 nm,wherein said wobble is configured to provide a wobble signal having a carrier level to noise ratio not less than 25 dB, and wherein:0.25.ltoreq.GW/R.sub.0 .ltoreq.0.45, or 0.65.ltoreq.GW/R.sub.0 and0.03.ltoreq.a.sub.w /GW.ltoreq.0.08,where a.sub.w, R.sub.0 and GW represent a wobble amplitude, a beam diameter of the light beam measured across said groove and a groove width, respectively.