Abstract: It is an object of the present invention to provide a method of recording information to an optical recording medium that is suited to achieving high data transfer rates.

Abstract: A method for manufacturing a stamper for an information medium in which a light absorbing layer containing a beam absorbing material to absorb a laser beam is formed on a glass base, a photoresist layer is formed on the light absorbing layer, the photoresist layer is irradiated with the laser beam to form a latent image, the photoresist layer is developed, and a photoresist matrix with a protrusion/depression pattern formed thereon is fabricated, stamper forming members are formed on the surface with the protrusion/depression pattern formed thereon of the photoresist matrix, the glass base of the photoresist matrix is removed, and the light absorbing layer is removed together with the photoresist layer by using strong alkaline solution. Since multiple exposure of the photoresist layer can be thus avoided, a photoresist matrix with a sharp protrusion/depression pattern and a stamper for information medium can be manufactured thereby.

Abstract: When information is recorded in an optical recording medium having a recording layer by irradiating a laser beam thereto through an optical system, the recording is carried out under the conditions: &lgr;/NA≦680 nm and n·Tw≦22 ns wherein the laser beam has a wavelength &lgr;, the optical system includes an objective lens having a numerical aperture NA, the window margin is Tw, and a signal length corresponding to the shortest recorded mark is n·Tw. The method provides for a high transfer rate and minimizes the jitter.

Abstract: An optical recording medium includes a substrate, a protective layer, three or more information recording layers formed between the substrate and the protective layer and transparent intermediate layers each formed between neighboring information recording layers and capable of recording data in the three or more information recording layers and reproducing data recorded in the three or more information recording layers by projecting a laser beam onto the three or more information recording layers via a light incidence plane constituted by the surface of either the substrate or the protective layer, wherein neighboring transparent intermediate layers facing each other across an information recording layer have different thicknesses. According to the thus constituted optical recording medium, it is possible to reduce interlayer cross-talk.

Abstract: It is an object of the present invention to provide an inspection method for judging whether or not a phase change type medium can be used as a write-once type medium.

Abstract: An optical recording medium according to the present invention includes a phase change recording layer where reversible phase changes between a crystal phase and an amorphous phase are used, wherein the recording layer includes at least Sb, Mn, and Te and, in a state corresponding to the crystal phase, has a structure where one diffracted ray is detected by X-ray diffraction as being present in respective ranges of spacings (Å) of 3.10±0.03, 2.25±0.03, and 2.15±0.03, in a range of between 3.13 and 2.12 spacing inclusive, with diffracted rays not being detected in other ranges within the 3.13 to 2.12 spacing range. Accordingly, the optical recording medium can be reliably crystallized even when the irradiation time of laser light is short, and also has superior thermal stability in an amorphous state.

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: Noise of the read-out signal is reduced in an optical information medium comprising a supporting substrate and a reflective layer disposed on the supporting substrate wherein the reading beam irradiates the medium from the side where the reflective layer is formed. In addition, noise of the read-out signal is reduced without adversely affecting the recording properties in an optical information medium comprising a supporting substrate, and a reflective layer and a recording layer disposed on the supporting substrate in this order wherein the recording beam irradiates the medium from the side where the reflective layer is formed. In the medium, the reflective layer has a crystallite size of up to 30 nm.

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: 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: There is provided an optical recording medium having a phase-change recording layer formed based on a drastically new concept of making the content of Mn still higher than the prior art while using Sb as a main component. The optical recording medium has a recording layer composed of a plurality of elements, and the recording layer contains Sb, and also has an Mn content of more than 20 atomic % but not more than 40 atomic %, on condition that the total amount of all the elements composing the recording layer is 100 atomic %.

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.

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, Sn and Ge as a primary component, and a second recording layer located in the vicinity of the first recording layer and containing Ag 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. 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: There is provided an optical recording medium formed based on a drastically new concept of forming a phase-change recording layer by using other elements than chalcogen. The optical recording medium has a phase-change recording layer thereof formed such that a reversible phase change of the phase-change recording layer between an amorphous phase and a crystalline phase can be utilized. The phase-change recording layer contains Sb as a main component and at least one element selected from the groups consisting of elements of other groups than group VIb and rare earth metal elements, as a sub-component.

Abstract: The optical recording medium of the present invention is a phase change optical recording medium which can be used as a write once medium and which can be recorded at a high recording density. The optical recording medium of the present invention is adapted for recording such that, when the recording beam has a wavelength of &lgr;, and objective lens of recording optical system has a numerical aperture of NA, minimum record marks formed are circular or ellipsoidal marks having a length of 0.4&lgr;/NA or less; and the medium is a write once medium wherein the recorded information can not be erased or rewritten at the minimum linear velocity used.

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, Sn, Zn and Cu as a primary component, and a second recording layer located in the vicinity of the first recording layer and containing Al 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 40 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: An optical recording medium includes a substrate, a protective layer, a first recording layer containing an element selected from a group consisting of Si, Ge, Sn, Mg, In, Zn, Bi and Al as a primary component, and a second recording layer located in the vicinity of the first recording layer and containing Cu as a primary component. When the optical recording medium is irradiated with a laser beam, the element contained in the first recording layer as a primary component and the element contained in the second recording layer as a primary component are mixed by the laser beam and a region whose reflection coefficient has been changed is formed, whereby information is recorded.

Abstract: In an optical recording medium of land/groove recording system, a sufficient tilt margin and a reduced cross talk are realized simultaneously with a sufficiently increased output. Provided is an optical recording medium having a light-transmitting substrate formed with grooves wherein the grooves and the region between adjacent grooves are used for the recording track, and a reading beam is irradiated through the light-transmitting substrate, wherein the relations: −12.6T+15.6≦x≦25T−3.8, and 0.55≦T≦0.68 are satisfied when the reading beam has a wavelength of &lgr;, the light-transmitting substrate has a refractive index at the wavelength &lgr; of n, the reading optical system has a numerical aperture of NA, recording track pitch is PT, the groove has a depth of &lgr;/(x·n), and T is PT/(&lgr;/NA).

Abstract: In an optical recording medium comprising a phase change recording layer (4) containing Sb and optionally, Te and/or In as a main component, the recording layer is able to be crystallized to provide a crystallized region which contains rhombohedral crystals consisting essentially of Sb and is substantially free of a crystal phase other than the rhombohedral crystals. When the recording layer contains a rare earth element, Zr, Hf, Ti or Sn as an auxiliary component, the medium has a dielectric layer (31) composed of silicon oxide, silicon nitride, aluminum oxide, or a mixture of zinc sulfide and at least 30 mol % of silicon oxide, disposed contiguous to and in front of the recording layer (4) as viewed from the recording/reading beam incident side. The medium has a high transfer rate and improved thermal stability.