Patent ID: 6528138
Filing Date: 2003-03-04
Classification: G11B,Y10T

Abstract:
An optical information medium for rewritable recording by means of a laser-light beam, said medium comprising a substrate having disposed on a side thereof:a first recording stack including a phase change type recording layer, sandwiched between two dielectric layers, a second recording stack including a phase change type recording layer, sandwiched between two dielectric layers; a transparent spacer layer, interposed between the first and the second recording stack, having a thickness larger than the depth of focus of the laser-light beam, and a metal mirror layer proximate the second recording stack and at a side of the second recording stack remote from the transparent spacer layer; and wherein: the first recording stack includes a phase change type recording layer of a kind selected from a kind with substantially growth dominated crystallization and a kind with substantially nucleation dominated crystallization; and the second recording stack includes a phase change type recording layer of a kind different from the kind selected for the first recording stack.