Abstract: An optical disc is constructed for operation in an alloying mode and includes first recording sublayer of Ge--Sb--Te and a second recording sublayer of Bi--Te. Apparatus is provided for recording information on an optical disc in the alloying mode or phase transformation mode in accordance with disc type information associated with the disc and readably by the apparatus. There is also provided an environmental aging technique for use in constructing optical discs to obviate significant dimensional changes in the discs during use between the extremes of the operating environment. There is further provided an optical disc construction and method in which an inorganic dielectric deposited on an organic substrate includes a hydrocarbon. There is additionally provided an optical disc construction and method in which a plasma polymer layer is disposed between an inorganic dielectric layer over the recording layer and a resin layer.

Abstract: The present invention provides an information recording medium including a first recording film formed on a substrate and having an amorphous phase made of an alloy containing at least Ge and Te, and a second recording film formed on the first recording film and made of a material with a relatively large light absorption coefficient, wherein the alloy of the first recording film exhibits a Raman scattering spectrum having scattering peaks at 140 to 160 cm.sup.-1 and 120 to 130 cm.sup.-1 and no scattering peaks at 100 to 110 cm.sup.-1, and recording is performed by changing optical characteristics by alloying the materials of the first and second recording films by radiating recording light on the first and second recording films.

Abstract: The present invention provides an information recording medium including a first recording film formed on a substrate and having an amorphous phase made of an alloy containing at least Ge and Te, and a second recording film formed on the first recording film and made of a material with a relatively large light absorption coefficient, wherein the alloy of the first recording film exhibits a Raman scattering spectrum having scattering peaks at 140 to 160 cm.sup.-1 and 120 to 130 cm.sup.-1 and no scattering peaks at 100 to 110 cm.sup.-1, and recording is performed by changing optical characteristics by alloying the materials of the first and second recording films by radiating recording light on the first and second recording films.

Abstract: A data recording medium includes a substrate, an undercoat layer formed on the substrate by plasma polymerization using a source gas containing fluorocarbon, and a recording layer formed on the undercoat layer and containing a metal selected from the group consisting of Ag, Au, and Cu, Te, C, and H, data being recorded in the recording layer by forming pits therein. A method of manufacturing a data recording medium includes forming an undercoat layer on a substrate by plasma polymerization using a source gas containing fluorocarbon, and forming a recording layer containing a metal selected from the group consisting of Ag, Au, and Cu, Te, C, and H by reactive sputtering in an atmosphere of a gas mixture of an Ar gas and a hydrocarbon gas.

Abstract: An information storage medium consists of a polycarbonate substrate and a recording layer formed on the substrate and containing an AgTe eutectic alloy, carbon, and hydrogen. Information is recorded on the medium by forming pits in the recording layer upon radiation of a laser beam, and is reproduced by radiating a reproducing laser beam onto the recording layer in which the pits are formed and detecting reflectances.

Abstract: An information storage medium comprises a substrate and a recording layer formed on the substrate containing Te, Ge, C and H. The recording layer is formed by sputtering, with a Ge-Te alloy being used as a target and with a mixed gas of a noble gas and a hydrocarbon being used as a sputtering gas. The hydrocarbon content in the sputtering gas falls within a range of 3 to 35%. The composition of the target is Ge.sub.x Te.sub.100-x (where x is expressed by atomic %, and 5.ltoreq.x.ltoreq.20).