Abstract: A recording medium is provided and includes; a substrate having a first area formed with a first groove and a second area formed with a second groove, at least one information layer provided on the substrate, and a protecting layer provided on the information layer. Predetermined binary information has previously been recorded on the first groove and the first groove is shallower or narrower than the second groove.

Abstract: To accomplish write-once type optical recording mediums that have excellent recording and reproducing characteristics and producibility and that are capable of being fabricated at low cost. A write-once type optical recording medium 10 has the structure of which an inorganic recording film 6, a dielectric film 4, and a light transmission layer 5 have been successively formed on a substrate 1. The inorganic recording film 6 is composed of a metal film 2 and an oxide film 3 successively formed on the substrate 1. When light is radiated to the inorganic recording film 6, oxygen is separated from the oxide film 3 due to the light catalyst effect, resulting in increasing the oxygen concentration on the metal film 2 side and largely varying the optical constant.

Abstract: In an optical recording medium 1 having a configuration in which on one main surface of a substrate 2, a reflective layer 3, a lower dielectrics layer 4, a recording layer 5, an upper dielectrics layer 6 and a light transmissive layer 7 are sequentially laminated, the lower dielectrics layer 4 is formed of a first lower dielectrics layer and a second lower dielectrics layer that inhibits a material that constitutes the first lower dielectrics layer and a material that constitutes the reflective layer 3 from reacting, and the upper dielectrics layer 6 is formed of a first upper dielectrics layer and a second upper dielectrics layer that inhibits a material that constitutes the first upper dielectrics layer and a material that constitutes the light transmissive layer 7 from reacting.

Abstract: To accomplish write-once type optical recording mediums that have excellent recording and reproducing characteristics and producibility and that are capable of being fabricated at low cost. A write-once type optical recording medium 10 has the structure of which an inorganic recording film 6, a dielectric film 4, and a light transmission layer 5 have been successively formed on a substrate 1. The inorganic recording film 6 is composed of a metal film 2 and an oxide film 3 successively formed on the substrate 1. When light is radiated to the inorganic recording film 6, oxygen is separated from the oxide film 3 due to the light catalyst effect, resulting in increasing the oxygen concentration on the metal film 2 side and largely varying the optical constant.

Abstract: A recording medium is provided and includes; a substrate having a first area formed with a first groove and a second area formed with a second groove, at least one information layer provided on the substrate, and a protecting layer provided on the information layer. Predetermined binary information has previously been recorded on the first groove and the first groove is shallower or narrower than the second groove.

Abstract: In an optical recording medium 1 having a configuration in which on one main surface of a substrate 2, a reflective layer 3, a lower dielectrics layer 4, a recording layer 5, an upper dielectrics layer 6 and a light transmissive layer 7 are sequentially laminated, the lower dielectrics layer 4 is formed of a first lower dielectrics layer and a second lower dielectrics layer that inhibits a material that constitutes the first lower dielectrics layer and a material that constitutes the reflective layer 3 from reacting, and the upper dielectrics layer 6 is formed of a first upper dielectrics layer and a second upper dielectrics layer that inhibits a material that constitutes the first upper dielectrics layer and a material that constitutes the light transmissive layer 7 from reacting.

Abstract: In order to increase the recording capacity while preventing jitter deterioration and a decrease of the modulation factor and thereby ensuring satisfactory recording characteristics, a first dielectric film, phase recording film, second dielectric film, reflection film and protective film are sequentially formed on a disc substrate having formed lands, grooves and wobbling on one major surface. The recording film is made of a GeInSbTe alloy, and the reflection film is made of an AgPdCu alloy or AlCu alloy. Composition of the GeInSbTe alloy is adjusted to contain Ge in the range of 1 to 8 wt %, In in the range of 2 to 6 wt %, and control Sb/Te in the range of 2.2 to 3.0. Composition of the AgPdCu alloy is adjusted to contain Pd in the range of 0.9 to 1.5 wt % and Cu not more than 1.5 wt %. Composition of the AlCu alloy is adjusted to contain Cu in the not more than 1.5 wt %. Groove depth is controlled in the range of 35 to 45 nm, groove width in the range of 0.35 to 0.

Abstract: In order to ensure CAV recording/reproduction while preventing jitter deterioration and modulation decrease and thereby ensuring sufficient recording properties, even at a linear velocity higher than 4.8 m/s, a first dielectric film, phase change versatile recording film, second dielectric film, reflection film and protective film are formed on a disc substrate having formed lands and grooves on one major surface. The recording film is made of a GeInSbTe alloy, and the reflection film is made of an AgPdCu alloy or AlCu alloy. Composition of the GeInSbTe alloy is adjusted to contain Ge in the range of 1 to 6 wt %, In in the range of 2 to 6 wt %, and control Sb/Te in the range of 2.2 to 3.0. Composition of the AgPdCu alloy is adjusted to contain Cu not more than 1.5 wt %. Regarding groove conditions, groove depth is controlled in the range of 40 to 50 nm, groove width in the range of 0.40 to 0.

Abstract: In order to increase the recording capacity while preventing jitter deterioration and a decrease of the modulation factor and thereby ensuring satisfactory recording characteristics, a first dielectric film, phase recording film, second dielectric film, reflection film and protective film are sequentially formed on a disc substrate having formed lands, grooves and wobbling on one major surface. The recording film is made of a GeInSbTe alloy, and the reflection film is made of an AgPdCu alloy or AlCu alloy. Composition of the GeInSbTe alloy is adjusted to contain Ge in the range of 1 to 8 wt %, In in the range of 2 to 6 wt %, and control Sb/Te in the range of 2.2 to 3.0. Composition of the AgPdCu alloy is adjusted to contain Pd in the range of 0.9 to 1.5 wt % and Cu not more than 1.5 wt %. Composition of the AlCu alloy is adjusted to contain Cu in the not more than 1.5 wt %. Groove depth is controlled in the range of 35 to 45 nm, groove width in the range of 0.35 to 0.

Abstract: In order to ensure CAV recording/reproduction while preventing jitter deterioration and modulation decrease and thereby ensuring sufficient recording properties, even at a linear velocity higher than 4.8 m/s, a first dielectric film, phase change versatile recording film, second dielectric film, reflection film and protective film are formed on a disc substrate having formed lands and grooves on one major surface. The recording film is made of a GeInSbTe alloy, and the reflection film is made of an AgPdCu alloy or AlCu alloy. Composition of the GeInSbTe alloy is adjusted to contain Ge in the range of 1 to 6 wt %, In in the range of 2 to 6 wt %, and control Sb/Te in the range of 2.2 to 3.0. Composition of the AgPdCu alloy is adjusted to contain Cu not more than 1.5 wt %. Regarding groove conditions, groove depth is controlled in the range of 40 to 50 nm, groove width in the range of 0.40 to 0.

Abstract: The present invention provides a rewritable optical disc which is compatible with a DVD-ROM reproduction apparatus and employs the groove recording method. The optical disc has a recording layer having a land 10 and a groove 9 onto/from which an information signal is recorded and reproduced with a light of a predetermined wavelength, wherein if it is assumed that the groove has a bottom width W1 and an opening width W2, then a groove average width X [&mgr;m] can be expressed as follows: X=(W1+W2)/2, and if the groove has a depth Y nm, then X and Y satisfy the following relationships: Y≧4736X2−4764X+1239 X≦−0.000127Y2+0.018624Y−0.075043 X>0.40.

Abstract: The present invention provides an optical disc capable of effectively reducing a reproduction signal jitter value and obtaining a wider record power margin assuring a reproduction limit jitter value to obtain a preferable recording/reproduction characteristic even after a number of times of recording repeated. The optical disc includes the following films successively formed on a substrate 2: a first dielectric film 3; a phase change recording film 4 whose phase is changed between a crystalline state and an amorphous state thereby to record an information signal; a second dielectric film 5; and a light reflection film formed on the phase change recording film 4 and constituted by an Al alloy containing Cu in a range from 0.1 to 1.0 atomic %.

Abstract: A phase-change optical disc has a recording layer formed from a phase-change material switchable between a crystalline state and an amorphous state. The recording layer is illuminated signal-wise by a light is focused onto the recording layer to change the phase thereof from crystalline to amorphous, to thereby write an information signal onto the recording layer. The phase-change material contains a GeSbTe alloy. The recording layer is formed by sputtering in an Ar gas atmosphere containing at least either N2 or O2 gas or both. The optical recording medium exhibits improved durability after repeated recording and maintains a stable and good write/read characteristic even after repeated cycles of signal recording.