Optical recording medium

Abstract

An over-writable magneto-optical recording medium in which a recording section has at least a first dielectric layer, a first recording layer, a second recording layer, and a second dielectric layer formed sequentially and a reflective layer and a protective layer formed on the recording section. A groove is formed on the transparent substrate along a recording track, both sidewalls of the groove are respectively formed into an independent wobbling shape, a relationship of 0.470≦W/Ø≦0.610 is effectuated when assuming the width of the groove as W, and a relationship of 0.120≦D(λ/n)≦0.142 is effectuated when assuming the depth of the groove as D, and the angle ⊖ between wall faces of the groove is kept at 150°±10°. An in-plane-directional refractive index may be set to a value in a range of 140 to 25 (nm) and a vertical-directional double-refractive index is set to a value in a range of 200 to 300 (nm). The first recording layer may be made of Gd, Fe, and Co. contains 28 to 30 (at %) of Gd, and has a thickness of 50 to 100 Å and the second recording layer is made of at least Tb, Fe, and Co, contains 22 to 24 (at %) of Tb, and has a thickness of 180 to 250 Å. A relationship of 0.55≦(d2/d1)≦0.9 is effectuated when assuming the thickness of the first dielectric layer as d1 and that of the reflective layer as d2 and the reflective layer is made of Al, Au, and Ti and contains 20 to 40 (wt %) of Au and 0.5 to 2.0 (wt %) of Ti.

Dependencies are inferred from the claim text.