Abstract: Phase-change type rewritable optical recording media, such as optical discs, optical cards, and optical tapes, where recorded data can be erased or overwritten and where data can be recorded with high speed and high density by applying a light beam can include an optical recording medium is one that includes a laminate member, which in various embodiments contains a transparent substrate, a first dielectric layer, a recording layer, a second dielectric layer, a light absorbing layer, and/or a reflecting layer. In various embodiments of the invention, the shortest distance between recorded marks in the recording direction along the track is less than &lgr;/NA, with &lgr; and NA denoting the wavelength of the light used and the numerical aperture of the objective lens of the optical head, respectively.

Abstract: An optical information recording medium having a multilayer structure comprising at least a lower protective layer, a phase-change type optical recording layer, an upper protective layer and a reflective layer, on a substrate, wherein the phase-change type optical recording layer has a composition of Gef(SbdTe1−d)1−f, where 0.65≦d≦0.85, and 0.01≦f≦0.20, whereby overwrite recording is carried out by modulation of light intensity of at least strong and weak two levels, so that a crystalline state is an unrecorded state, and an amorphous state is a recorded state.

Abstract: There is disclosed an optical recording media having a transparent substrate; a dye recording layer containing a metal complex of a porphym or phthalocyanine dye on said transparent substrate; a reflective layer provided on said dye layer wherein the reflective layer which is a mixture of silver and gold in such proportions that the gold is between about 0.5 and 15 atomic percent of said mixture; and a protective layer formed over said reflective layer. In accelerated keeping tests, the media of the invention exhibits excellent stability.

Abstract: A phase change optical disk medium includes a disklike substrate, and a recording layer formed by a laminate of a plurality of thin layers including a phase change layer. Information marks are recorded on the phase change layer by phase changes from a crystal phase to an amorphous phase and vice versa. The recording layer has tracks for recording information marks formed by groove portions and land portions respectively taking alternate concave and convex shapes. The track has an interval in range of 0.54 to 0.64 &mgr;m and the recording layer has a ratio of the optical reflectance of 0.35 or less when the phase change layer has changed to the amorphous phase in case where the optical reflectance of the recording layer is 1 when the phase change layer is in the crystal phase.

Abstract: Phase-change type, reversible optical information recording medium, being possible for recording, reproducing, erasing, and rewriting of information, by use of a laser beam. This invention consists of recording thin film of ternary elements, for example, containing Ge, Te, Sb/or Bi or quaternary elements containing the fourth element of Se with which a part of Te is replaced, which is established on such surface—flat substrates as glass or plastics. In this case, the component ratio of Te and Se is selected not to be excess for other elements, such as Ge, Sb/or Bi so as to be fixed as stable compounds of stoichiometric compositions of GeTe, Sb2Te3/or Bi2Te3, or GeSe, Sb2Se3/Bi2Se3 when crystallized. Strictly speaking, a concentration of each component is selected to have proper ratio of the number of atomes each other so as to represent whole composition as the sum of each component. By this treatment, it is possible to have high crystallization speed and long cyclability of recording/erasing.

Abstract: A user-removable optical data storage system is provided. A rotatable first-surface medium is enveloped in a cartridge. The cartridge provides relatively large data capacity such as about 0.25 Gbytes or more despite a relatively small size such as about 35 mm×35 mm×3 mm. Preferably the cartridge substantially seals the data surfaces of the medium when the cartridge is withdrawn from a drive and at least a portion of one surface is automatically exposed to the objective of an optics arm when said cartridge is inserted in the drive. Tracking involves rotating an optic arm about an axis parallel to the disk rotation axis. Focus can involve pivoting the arm about an axis parallel to the disk surface.

Abstract: A layer arrangement for an optical component or an optical data storage element such as a CD, a DVD, a hybrid disk or a super audio disk, has at least one layer which is at least predominantly Si(1-x)Ge(x)Hy as a spectrally selective layer for a predominant reflection of light in a lower part of a spectral range of 600 nm to 800 nm and for a predominant transmission of light in an upper part of said spectral range. The values for x and y are 0.1<x≦0.9 and 0≦y≦0.5.

Abstract: A method of initializing a phase-change optical disk which is capable of preventing enlargement of an amount of jitter which takes place when the number of overwriting operations does not exceed several times. The surface of the phase-change optical disk, on which information signals will be recorded, is crystallized. Then, signals are recorded with marks and spaces in grooves along tracks of the phase-change optical disk so that initialization is performed. The initialization is performed in such a manner that the length of each of spaces is shorter than a shortest length of spaces of information signals.

Abstract: The thickness of the transparent substrate of an optical disk has been selected from the range from 0.2 mm to 0.4 mm. The wavelength of a light beam passing through the transparent substrate has been selected from the range from 400 to 420 nm. The numerical aperture of an objective for converging the light beam has been selected from the range from 0.60 to 0.75.

Abstract: A magneto-optic recording medium includes a second auxiliary magnetic film, a first auxiliary magnetic film and a magneto-optic recording film on a substrate. The auxiliary magnetic films change from in-plane magnetization to vertical magnetization at critical temperatures TCR1 and TCR2. Since they have the relation TCR1>TCR2, the magnetic domain transferred from the magneto-optic recording film to the first auxiliary magnetic film at the time of reproduction is expanded in diameter and is transferred to the second auxiliary magnetic film when the temperature profiles of the auxiliary magnetic films inside an optical spot are utilized. The magnetic domain of the magneto-optic recording film can be expanded and transferred, too, by means of magnetostatic coupling by using a non-magnetic film in place of the first auxiliary magnetic film. Pulse reproduction light subjected to power modulation in synchronism with a reproduction clock can be used at the time of reproduction.

Abstract: A magneto-optical recording medium is composed of a base which has a property that a light can be transmitted therethrough, a readout layer formed on the base, which has in-plane magnetization at room temperature, whereas, a transition occurs from in-plane magnetization to perpendicular magnetization as the temperature thereof is raised and a recording layer formed on the readout layer for recording information magneto-optically. A recording and reproducing method and the optical head are designed for the magneto-optical recording medium. By the recording and reproducing method using the optical head, information recorded at high density can be reproduced.

Abstract: There is provided a phase-change type optical recording medium, including: a substrate; a recording layer formed on the substrate, phase condition of the recording layer being changed when a laser beam is radiated thereonto, to thereby record, erase or reproduce data into or from the recording layer; and a reflection layer formed on the recording layer for reflecting a laser beam having been radiated onto the recording layer. The recording layer is formed so that the following equation is established: Rc>Rm>Ra wherein Rc indicates a reflectivity to be obtained when the recording layer is in crystal condition, Ra indicates a reflectivity to be obtained when the recording layer is in amorphous condition, and Rm indicates a reflectivity to be obtained when the recording layer is in mixed condition of molten condition and crystal or amorphous condition.

Abstract: An optical recording medium is provided which achieves a higher recording capacity. This optical recording medium includes a base formed of thermoplastic resin which has a thickness ranging from between approximately 0.3 to 1.2 mm, a guide groove formed on the base, an information recording layer formed at least of a reflective film and an organic dye recording layer provided on the guide groove, and a light transmissive layer having a thickness ranging from between approximately 3 to 177 &mgr;m. In this optical recording medium, the unevenness &Dgr;t of the thickness of the light transmissive layer is set within the range of: &Dgr;t≦±5.26(&lgr;/N.A.4)(&mgr;m) wherein N.A. represents a numerical aperture of an optical head device of the optical disk recording and/or reproducing apparatus and &lgr; represents the wavelength of laser light utilized by the optical disk recording and/or reproducing apparatus.

Abstract: A very-high-density memory device which utilizes a scintillating medium for data storage. In one mode, the device operates as a read-only-memory (ROM) unit. In another mode, the device functions as a one-time-write (OTW) and then read-only-memory unit. In an exemplary embodiment, information is read at high data rates from a rotating data-storage disk or cylinder with an electron beam and sensitive photodetector. Two methods of following the data tracks on the storage medium are provided. Masks are provided for use in patterning the data or data tracks. These masks may also be used to pattern very-high-density media for other applications such as magnetic memory and optical near-field memory. A method of patterning radially-periodic structures using interferometric lithography is also provided.

Abstract: A phase change optical recording medium has on a substrate a recording layer consisting essentially of a Sb base thin film and a reactive thin film. The Sb base thin film is formed by depositing a Sb base material containing at least 95 at % of Sb to a thickness of 70-150 Å. The reactive thin film is formed of a material which forms a phase change recording material when mixed with Sb. The reactive thin film is typically formed of an In—Ag—Te or Ge—Te material. Stable write/read characteristics are accomplished at the first overwriting, initializing operation is eliminated, and rewriting is impossible at the same linear velocity as recording.

Abstract: An information storage medium includes a substrate, a thin film formed on the substrate and having a reflectance changed by a phase change caused by irradiation of an energy beam irradiated via the substrate and a first reflective layer and a second reflective layer on the film directly or via an intermediate layer. The thin film includes one of In3SbTe2, In35Sb32Te33, In31Sb26Te43 and Ag—In—Sb—Te. The first reflective layer and the second reflective layer are piled up in the recited order from a thin film side with the first reflective layer consisting of a material having an attenuation factor k of 2 or less and selected from a group of silicon based materials and the second reflective layer consisting of a material having an attenuation factor k of at least 3.

Abstract: An optical disk has a recording region divided into ones, each zone including physical tracks which are divided into a number of sectors. The optical disk further includes a structure management table which stores an attribute for each zone indicating whether the corresponding zone is a recording area which permits rewriting or a recording area that does not permit rewriting.

Abstract: An optical recording device including a medium having a first recording level, which includes a first active film having amorphous areas and crystalline areas, the first recording level being configured to produce a phase difference between an optical beam reflected by the amorphous areas and an optical beam reflected by the crystalline areas; and a second recording level superimposed on the first recording level and including a second active layer with first areas and second areas, the second recording level being configured to produce an intensity difference between an optical beam reflected by the first areas and an optical beam reflected by the second areas.

Abstract: An optical information recording medium includes a substrate with guide grooves thereon, a recording layer provided on the substrate, including a recording material of which phase is reversibly changeable from a stable state to a semistable state and vice versa, a heat-resistant dielectric protective layer provided on the recording layer, including a protective material which includes Zn, Si, S and O, and a light reflection and heat dissipation layer provided on the heat-resistant dielectric protective layer.

Abstract: A hybrid optical recording disc having a substrate and a recording layer disposed over the substrate, the substrate having a read-only (ROM) area in which a groove is modulated by depressions in the substrate and a recordable area in which the groove from the read-only area extends into the substrate in the recordable area, the groove in the read-only area forming wobbling tracks having a depth greater than 170 nm.

Abstract: Reading partly written record carriers using a reading device which positions the read head on the basis of written marks presents problems when an information block behind a non-written area must be read. A writing device and a method of writing information blocks on a record carrier of a rewritable type such as a CD-RW or a DVD-RAM include the following. First, record carrier areas which are in use for writing information blocks, are detected, for example, using the corresponding writing instructions. Subsequently, it is detected whether boundary areas adjoining the areas which are in use are unwritten. In that case, the boundary areas are initialized by writing them with dummy information, preferably with dummy information blocks comprising address information in the conventional manner. A record carrier is provided with status information which is indicative of the non-written state of areas. A reading device is provided with search means for searching written areas.

Abstract: A rewritable, heat sensitive, color image recording medium having a pair of opposed substrate sheets at least one of which is transparent, and a heat sensitive layer interposed between the substrate sheets and containing a cholesteric liquid crystal compound having a molecular weight of not greater than 2,000 and a glass transition point of at least 35° C. A color image is formed on the recording medium by varying imagewise the temperature of the heat sensitive layer from a first temperature to a second temperature such that the cholesteric liquid crystal compound assumes a cholesteric liquid crystal phase at at least one of the first and second temperatures. The image is fixed by rapidly cooling the recording medium to a temperature lower than the glass transition point of the cholesteric liquid crystal compound.

Abstract: There is disclosed a recordable optical element that has a substrate and on the surface of the substrate, a recording layer and a light reflecting layer. The recording layer has a material with the formula TeaGebCcHdOe wherein a, b, c, d, and e are atomic percents and (c+d)>40, d>10, a>5, b>5, and e≧0 such that a+b+c+d+e=100; and the reflecting layer and the recording layer being selected such that the element Rmax or Rmin (element reflectivity) is about or greater than 70% at about 780 nm.