Abstract: An optical recording medium includes a phase-change recording layer where reversible phase changes between a crystal phase and an amorphous phase are used. The recording layer includes at least Sb, Tb, and Te. When indexing as a hexagonal lattice has been performed in a state corresponding to the crystal phase, the recording layer has a structure where an axial ratio c/a of a c-axis length to an a-axis length in the hexagonal lattice is between 2.590 and 2.702 inclusive.

Abstract: An optical recording medium includes a recording layer, a first dielectric layer disposed on the side of a light incidence plane through which the laser beam enters with respect to the recording layer, a second dielectric layer disposed on the side opposite to the light incidence plane with respect to the recording layer, a heat radiation layer disposed on the side of the light incidence plane with respect to the first dielectric layer and a reflective layer disposed on the side opposite to the light incidence plane with respect to the second dielectric layer, the recording layer containing a phase change material represented by an atomic composition formula: SbaTebGecMnd, where a is equal to or larger than 55 and equal to or smaller than 70, c is equal to or larger than 4 and equal to or smaller than 10, d is equal to or larger than 10 and equal to or smaller than 20, a/b is equal to or larger than 2.8 and equal to or smaller than 3.5 and a/d is equal to or larger than 3.0 and equal to or smaller than 6.

Abstract: The optical recording medium of the invention comprises a recording layer and at least one mixed dielectric layer. The mixed dielectric layer contains cerium oxide and an additive compound. The additive compound is at least one compound selected from among aluminum oxide, chromium oxide, iron oxide, manganese oxide, niobium oxide, magnesium oxide, zinc oxide, titanium oxide, yttrium oxide, tantalum oxide, antimony oxide, zirconium oxide, bismuth oxide and magnesium fluoride. The optical recording medium has a high storage reliability and satisfactory recording/reading characteristics.

Abstract: An optical recording medium includes a recording layer, a first dielectric layer disposed on the side of a light incidence plane through which the laser beam enters with respect to the recording layer, a second dielectric layer disposed on the side opposite to the light incidence plane with respect to the recording layer, a heat radiation layer disposed on the side of the light incidence plane with respect to the first dielectric layer and a reflective layer disposed on the side opposite to the light incidence plane with respect to the second dielectric layer, the recording layer containing a phase change material represented by an atomic composition formula: SbaTebGecMnd, where a is equal to or larger than 57 and equal to or smaller than 74, c is equal to or larger than 2 and equal to or smaller than 10, d is equal to or larger than 5 and equal to or smaller than 20, (a+d) is equal to or larger than 74 and equal to or smaller than 81 and a/b is equal to or larger than 2.9 and equal to or smaller than 4.

Abstract: An optical recording medium and a recording system for the same are provided, which can dissipate heat produced by a laser beam during recording operations to thereby increase the erasing power margin of the laser beam which allows the playback jitter value to take on a certain value or less.

Abstract: An optical recording medium is provided, which has reduced degradation in jitter caused by manufacturing variations of a semiconductor laser emitting laser beams or variations in output power of laser beams, and which dissipates heat in the recording layer during recording by laser beams to increase the power margin of the laser beam providing playback jitter values at a certain level or less.

Abstract: An optical information medium is provided. The medium comprises a supporting substrate, an information recording layer thereon, and a light-transmitting layer thereon and a recording or reading laser beam enters the recording layer through the light-transmitting layer, and in such medium, recording/reading characteristics are improved when the beam spot of a laser beam has a small diameter and the linear velocity is high with the function of the light-transmitting layer to protect the information recording layer maintained at a sufficient level. Also provided is a medium wherein storage stability is improved.

Abstract: An optical recording medium includes a recording layer in which a record mark can be formed by projecting a laser beam thereonto, a first dielectric layer disposed on the side of a light incidence plane with respect to the recording layer, a second dielectric layer disposed on the opposite side to the light incidence plane with respect to the recording layer, a heat radiation layer disposed on the side of the light incidence plane with respect to the first dielectric layer and a reflective layer disposed on the opposite side to the light incidence plane with respect to the second dielectric layer, the recording layer containing a phase change material represented by a general formula: (SbxTe+x)+y My wherein M is an element other than Sb and Te, the first dielectric layer containing a mixture of ZnS and SiO2, the reflective layer containing Ag or alloy containing 90 atomic % or more of Ag, and the heat radiation layer containing 90 atomic % or more of aluminum nitride.

Abstract: A method is provided for preparing an optical information medium comprising a disk-shaped supporting substrate having a center hole, an annular information recording area thereon, and an annular resin-based light-transmitting layer on the information recording area through which recording/reading laser beam is transmitted. In the formation of the light-transmitting layer, a coating fluid containing an actinic radiation-curable resin is fed onto the supporting substrate having the information-recording area formed thereon and the supporting substrate is rotated for spreading the coating fluid over the supporting substrate to thereby form a resin layer, and subsequently, the resin layer is irradiated with actinic radiation to thereby cure said resin layer while reducing the rotation speed of the supporting substrate. This method is capable of suppressing the size of the bump formed in the outer peripheral region of the light-transmitting layer.

Abstract: Reduction in noise of the read out signal as well as enhanced storage reliability are realized in an optical recording medium comprising a supporting substrate, and a reflective layer, a recording layer, and a light-transmitting substrate disposed on the supporting substrate in this order. The optical recording medium comprises a supporting substrate 20, and an intermediate layer 10 comprising an amorphous material, a reflective layer 5 comprising a polycrystalline material, a recording layer 4, and a light-transmitting substrate 2 disposed on the supporting substrate in this order. The write beam and the read beam are directed through the light-transmitting substrate 2.

Abstract: An optical recording medium wherein a recording layer, an absorbent layer and a radiating layer are provided in this order as seen from a recording/reproducing light incidence side and recording/reproduction is carried out on a condition that an extinction coefficient k of the absorbent layer is k>0 in a wavelength of recording/reproducing light, and a relationship between a wavelength &lgr; of the recording/reproducing light and a numerical aperture NA of an irradiating optical system of the recording/reproducing light is &lgr;/NA≦680 nm. An optical recording medium wherein an absorbent layer and a recording layer are provided in this order as seen from a recording/reproducing light incidence side and an extinction coefficient k of the absorbent layer is k>0 in a wavelength of recording/reproducing light, and a signal including a minimum mark having a mark length Ms of MS≦0.17 &mgr;m is recorded.

Abstract: In an optical information medium comprising a supporting substrate, an information recording layer thereon, and a light-transmitting layer wherein a recording/reading laser beam enters the recording layer through the light-transmitting layer, the light-transmitting layer is formed of a resin and has a tensile strength at break of 5-40 MPa, a tensile elongation at break of 15-100%, and a tensile modulus of 40-1,000 MPa. The medium has improved recording/reading characteristics when a laser beam defines a beam spot having a small diameter of up to 300 &mgr;m and the medium is rotated at a high linear velocity of at least 8 m/s.

Abstract: An optical recording/reproducing method and an optical recording medium capable of performing excellent optical recording with a simple structure in a recording layer made of environmentally friendly materials. The optical recording medium has a recording layer on a substrate. The recording layer has a pair of dielectric layers of which states are altered by a laser beam that is an energy beam of which intensity is modulated according to information to be recorded. This recording layer also has a assisting-material layer sandwiched by these dielectric layers. The assisting material layer includes an element selected from Sn, Ti, Si, Di, Ge, and C as a principle component, while the dielectric material as a base material for the dielectric layers is any one of ZnS, SiO2, AlN, and Ta2O5.

Abstract: An optical recording/reproducing method and an optical recording medium capable of performing excellent optical recording with a simple structure in a recording layer made of environmentally friendly materials. The optical recording medium has a recording layer on a substrate. The recording layer has a pair of dielectric layers of which states are altered by a laser beam that is an energy beam of which intensity is modulated according to information to be recorded. This recording layer also has a recording assist layer sandwiched by these dielectric layers. The recording assist layer includes an element selected from Sn, Ti, Si, Bi, Ge, and C as a principle component, while the dielectric material as a base material for the dielectric layers is at least one of ZnS, SiO2, AlN, and Ta2O5.

Abstract: A method and apparatus is provided for preparing an optical information medium comprising a disk-shaped substrate having a center hole, an information recording layer thereon, and a resin-based light-transmitting layer thereon by which recording/reading laser beam is transmitted. The apparatus includes a rotating table (2) for holding and rotating the substrate (100) having the information recording layer borne thereon, a plug means (3) including a disk member (31) for closing the center hole (101) and an integral support shaft (32), and a nozzle (4) for feeding a coating fluid containing the resin to the outer periphery of the support shaft (32), wherein the coating fluid is flowed from the support shaft to the disk member, then over the substrate, thereby forming the light-transmitting layer having a minimized thickness variation.

Abstract: An optical information medium comprising a supporting substrate, an information recording area on the supporting substrate, and a light-transmitting layer covering at least the information recording area, wherein the information recording area is irradiated with the recording/reading laser beam through the light-transmitting layer, and wherein the light-transmitting layer is highly scratch resistant upon contact with the optical pickup is provided. Also provided is an optical information medium which has a scratch-resistant light transmitting layer, and which experiences reduced vibration in high-speed rotation without suffering from problems in focus servo and tracking servo. In such optical information medium, the surface of the medium on the side of the laser beam incidence at least in the part above the information recording area has a dynamic coefficient of friction of up to 0.4.

Abstract: An optical recording/reproducing method and an optical recording medium capable of performing excellent optical recording with a simple structure in a recording layer made of environmentally friendly materials. The optical recording medium has a recording layer formed on a substrate and made of a mixture of a recording assist material and a dielectric material. A laser beam of which intensity is modulated in accordance with information to be recorded is irradiated onto this recording layer to cause a state change in the recording assist material and/or the dielectric material. The information can be recorded by changing optical characteristics thereof such as reflectivity. The recording assist material includes an element selected from Sn, Ti, Si, Bi, Ge, and C as a principle component, while the dielectric material as a base material for the dielectric layers is at least one of ZnS, SiO2, AlN, and Ta2O5.

Abstract: In an optical information medium comprising a supporting substrate, an information recording layer thereon, and a light-transmitting layer wherein a recording/reading laser beam enters the recording layer through the light-transmitting layer, the light-transmitting layer is formed of a resin and has a tensile strength at break of 5-40 MPa, a tensile elongation at break of 15-100%, and a tensile modulus of 40≧1,000 MPa. The medium has improved recording/reading characteristics when a laser beam defines a beam spot having a small diameter of up to 300 &mgr;m and the medium is rotated at a high linear velocity of at least 8 m/s.

Abstract: An optical recording medium includes a substrate, a first recording layer formed on the substrate and containing an element selected from the group consisting of Si, Ge, C and Al as a primary component, and a second recording layer located in the vicinity of the first recording layer and containing Zn as a primary component, the optical recording medium being constituted to be irradiated by a laser beam projected onto the side opposite from the substrate and the total thickness of the first recording layer and the second recording layer being equal to or thinner than 30 nm. According to the thus constituted optical recording medium, it is possible to decrease a noise level and improve a C/N ratio in a reproduced signal.

Abstract: In an optical recording medium wherein grooves or lands formed on the supporting substrate are used for the recording tracks, and wherein prepits are also formed, production of the supporting substrate and high density recording are facilitated. This medium comprises a supporting substrate and a recording layer on the substrate wherein the surface of the supporting substrate on which the recording layer is formed is formed with alternating continuous convex portions and continuous concave portions which are substantially parallel to each other. The adjacent continuous convex portions are connected by bridging convex portions extending in transverse direction, and the bridging convex portion has a planar configuration that its width is minimum at or near the center between the adjacent continuous convex portions. The supporting substrate is produced by using a master disk which has a resist layer formed with mother patterns of each of the continuous convex portions, continuous concave portions, and prepits.