Abstract: A CD-ROM has an obscurable section wherein exists a photosensitive mask material layer or constituent operative to alter the optical properties of areas subjected to prolonged exposure to the CD-ROM read laser radiation. Digital information stored on a CD-ROM is made accessible by use of a password, which is generated from user machine unique information, and which is written on the CD-ROM via selective exposure of the CD-ROM to the radiation used to read the CD-ROM.

Abstract: An optical recording medium includes a crystallizing layer for enhancing the crystallization of a phase change memory layer, an energy storage layer for aiding the state transformations of a phase change memory layer, and/or a modifying element for increasing absorption and contrast at short wavelengths. An optical data storage and retrieval system containing same. Also a light-plasmon coupling lens including an optically transparent substrate having a light incident surface and a light-plasmon coupling surface opposite the light incident surface. The light-plasmon coupling surface including at least a set of circular concentric peaks/valleys which form a Fourier sinusoidal pattern in the radial direction of the circular concentric peaks/valleys. A conformal layer of metal is deposited on the light-plasmon coupling surface of the substrate and has aperture at the center of thereof through which plasmons are transmitted.

Abstract: An optical information-recording medium comprises (a) a disk-shaped substrate having a first main surface and a second main surface opposite to the first main surface; an incidence surface of the medium being located to be nearer to the first main surface than the second main surface; (b) a recording layer formed on the substrate; and (c) a signal generation layer formed on the substrate in such a way as to be nearer to the incident surface than the recording layer. The signal generation layer allows an incident light beam irradiated to the incidence surface to pass through and allows a reflected light beam from the recording layer to pass through. The signal generation layer includes a transmittance changing region having a transmittance with respect to the incident light beam different from its neighborhood, thereby generating a repeated transmittance change according to rotation of the medium.

Abstract: An optical recording medium has a phase-change recording layer containing Sb and Te as essential elements therefor, to which is added at least one element selected from the group consisting of Ag, Au, Cu, Zn, B, Al, Ga, In, Si, Ge, Sn, Pb, N, P, Bi, La, Ce, Gd, and Tb, the recording layer being capable of assuming an amorphous phase changed from a crystalline phase by the application of a laser beam thereto, thereby optically recording information. Recording marks are formed in the recording medium by converting a light emission wave of laser beam into a recording pulse train comprising a plurality of on-pulses and off-pulses, with a recording frequency being continuously changed corresponding to the location of each of the recording marks in the radial direction of said recording medium. A recording apparatus has laser beam driving circuit means, signal generation means, and signal transmission means for achieving the above recording method.

Abstract: A rewritable recording medium having a first adjustment region recorded with first signal information, a data portion recorded with data information after the first adjustment region, and second adjustment region recorded with a second signal information after the data portion. Each time the first signal information is rerecorded, a length of the first adjustment region changes and a start position of the first adjustment region changes.

Abstract: An optical recording medium having two or more information recording layers in which information is recorded at a high recording density. The optical recording medium is comprised of information recording layers between a first surface at which light is incident and a second surface opposite the first surface. The first information recording layer nearest to the second surface is a phase-modulation information recording layer, and the second information recording layer is a reflectance-modulation information recording layer.

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: A method for recording information on a rewritable recording medium includes recording first synchronizing signal information in a first synchronizing signal portion on the rewritable recording medium, recording second synchronizing signal information in a second synchronizing signal portion following the first synchronizing signal portion on the rewritable recording medium, recording data information in a data portion of the rewritable recording medium after the second synchronizing signal portion by forming marks in the data portion. The data information corresponds to both ends of each the marks. The marks and spaces between the marks are substantially randomly inverted each time the information is recorded and a length of the first synchronizing signal portion changes and a start position of the first synchronizing signal portion changes. A change of the start position of the first synchronizing signal portion is smaller than a change of the length of the first synchronizing signal portion.

Abstract: An information recording medium includes a first information layer and a second information layer. The first information layer includes a first recording layer in which a reversible phase change is caused between a crystalline phase and an amorphous phase by irradiation of a laser beam or application of current. The second information layer includes a second recording layer in which a reversible phase change is caused between a crystalline phase and an amorphous phase by the irradiation of the laser beam or the application of the current. The first recording layer is made of a first material, the second recording layer is made of a second material, and the first material is different from the second material.

Abstract: An optical information recording medium including a substrate, a light absorbing layer which is located overlying the substrate and in which marks are formed to store information and a light reflection layer located overlying the light absorbing layer including a crystal, wherein the optical information recording medium satisfies the relationship, Lt/4?Lc?Lm, wherein Lc represents the average particle diameter of the crystal of the light reflection layer, Lm represents the minimum length of the marks, and Lt represents the thickness of the light reflection layer.

Abstract: The present invention is directed to a three-dimensional memory apparatus for storing information in a volume comprising of an active medium. The active medium is capable of changing from a first to a second isomeric form as a response to radiation of a light beam having an energy substantially equal to a first threshold energy. The concentration ratio between a first and a second isomeric form in any given volume portion represents a data unit. The active medium in the memory apparatus comprises of diarylalkene derivatives, triene derivatives, polyene derivatives or a mixture thereof. The invention is further directed to means for reading the data units from the isomeric states of the active medium in different portions of said active medium where the two isomeric forms have a substantially different absorption coefficient for absorbing energy of a second threshold energy. Reading may also be carried out by measuring the scattering pattern of the two isomeric forms.

Abstract: At least one information layer including a recording layer contains a material that can exhibit a transition between two optically different states in response to irradiation with a laser beam as a main component is provided on a substrate, and the material is configured so as to exhibit an energy gap ranging from 0.9 eV to 2.0 eV in the amorphous state. The information layer is configured to have a light transmittance of not less than 30% when irradiated with a laser beam having a wavelength ranging from 300 nm to 450 nm. It is possible to achieve excellent recording/reproduction, even if a plurality of recording layers are provided in the recording medium, when this medium is irradiated with a laser beam with a wavelength in the foregoing range from one side of the medium.

Abstract: An information recording medium includes a first information layer and a second information layer. The first information layer includes a first recording layer in which a reversible phase change is caused between a crystalline phase and an amorphous phase by irradiation of a laser beam or application of current. The second information layer includes a second recording layer in which a reversible phase change is caused between a crystalline phase and an amorphous phase by the irradiation of the laser beam or the application of the current. The first recording layer is made of a first material, the second recording layer is made of a second material, and the first material is different from the second material.

Abstract: Increase of jitter in a phase change optical recording medium is suppressed with no extreme decrease in the crystallization speed of the recording layer when the medium is overwritten at a high linear velocity. In addition, in a disk-shaped medium operated at a constant angular velocity, the overwriting is accomplished with the increase of jitter suppressed over the entire area of the medium. Provided is an optical recording method for recording a disk-shaped optical recording medium having a phase change recording layer which is rotated at a constant angular velocity, wherein amorphous recorded marks are formed in the recording layer. In this method, the minimum recorded mark is formed such that WL/ML incrementally or gradually decreases from the radially inner side to the radially outer side of the optical recording medium, when the minimum signal has a length of SL, and when the minimum recorded mark corresponding to said minimum signal has its maximum width of MW, EW is 0.

Abstract: An initialization method of an optical recording medium having a plurality of optical recording layers capable of reducing initialization unevenness due to light interference caused at the time of initialization without deteriorating information recording/reproducing signal characteristics of the optical recording layers is provided.

Abstract: An optical information recording medium for recording information by a plurality of record mark lengths, wherein the shortest mark length is at most 0.5 ?m, and a crystal state is an unrecorded or erased state and an amorphous state is a recorded state, wherein the erasing is carried out by recrystallization which substantially proceeds by crystal growth from an interface between the amorphous portion or a melt portion and a peripheral crystal portion; and an optical recording method suitable therefore. The medium of the present invention has characteristics that overwriting can be made at a high speed, the jitter of mark edge is small, mark length modulation recording can be made at a high density, and the formed mark is excellent in the stability with the lapse of time.

Abstract: The rewritable data storage medium (1) has a rewritable recording layer (9) provided with a tracking structure (8). Said layer (9) has a data recording area (5). An erasable identification mark is present in an identification mark area (4, 4?) other than the data recording area (5). The data recording area (5) has a first tracking structure (8?), whereas the identification mark area (4, 4?) is substantially free from a tracking structure or has a second tracking structure (8?) substantially different from the first tracking structure (8?). Thus erasure of the identification mark is practically impossible, because the location of the erasing spot of a recorder cannot be controlled precisely in radial direction.

Abstract: A data storage unit includes a data storage layer with multiple storage areas having a storage medium disposed thereon that changes between a plurality of states for writing and reading information. An array of beam emitters, such as laser light probes or near-field light sources, are spaced in close proximity to the data storage layer. A layer (LASL) adjacent to the storage layer generates carriers (electrons, holes or photons) in response to the light beams. Data is read by directing a light beam onto the data storage layer. The storage medium on the data storage layer affects the generation of carriers or alters the transport of carriers after generation by the LASL, depending upon the state of the storage medium. The carriers are detected in a detection region in carrier communication with the LASL to detect the presence of data. The detection region may comprise any type of region for detecting carriers, including a semiconductor diode junction and a photoconductive region.

Abstract: The present invention is a multilayer optical disc formed of a plurality of information recording sections having a phase change recording layer. A first information recording section provided at a laser-incident side uses, as a recording material, a phase change recording material which uses Sb and Te as major components and satisfies their ratio of 2.3<Sb/Te?4.0 according to the atomic ratio. Since this phase change recording material provides a fast crystallization speed, it is possible to stably record, reproduce, and rewrite an information signal at a high transfer rate.

Abstract: A phase change optical information recording medium including: a substrate; and a recording layer which is located overlying the substrate and in which marks are to be formed to store information, wherein the substrate includes plural sessions including a first session in which pits are formed and which includes a RAM region including a groove and a wobble signal, and a program memory area in which pits are formed and which includes position information of the first session and does not include disc ID information of the phase change optical information recording medium.

Abstract: An optical recording medium having a higher improved read accuracy is disclosed. In the case of irradiating a laser beam to an optical recording medium including an optical reflective layer and a recording layer so as to record information therein, in the recording layer, a virtual recording cell having an arbitrary unit length and a unit width perpendicular to the unit length is continuously defined. In the case where the laser beam is irradiated to the virtual recording cell over the entire allowable irradiation time T securable to one virtual recording cell, a reference power of the laser beam is preset so that an optical reflectance of the virtual recording cell can be reduced more than 50% with respect to the initial reflectance.

Abstract: A method and system for providing copy-protected optical medium using transient optical state change security materials capable of changing optical state when exposed to a wavelength of about 630 nm to about 660 nm and software code to detect such change in optical state.

Abstract: An information recording medium capable of high-density recording and accurate reproduction and also capable of repeated recording and reproduction, an information recording device that employs the information recording medium has a Co—Si oxide thin film 1 constructed such that columnar crystals 2 are separated by an intergranular phase 3 which contains SiO2 having a lower coefficient of thermal conductivity than the columnar crystals 2. Therefore, the intergranular phase 3 prevents heat transfer from one columnar crystal 2 to another. In addition, the intergranular phase 3 separates columnar crystals 2 from each other, so that the crystalline structure of each columnar crystal 2 is not affected by its adjacent columnar crystal 2.

Abstract: An initialization method of an optical recording medium having a plurality of optical recording layers capable of reducing uneven initialization due to light interference caused at the time of initialization without deterioration of information recording/reproducing signal characteristics of the recording layers is provided.

Abstract: An optical information recording method including: irradiating a recording medium with laser light, wherein 0 signals having width nT are recorded or rewritten using continuous laser light having a power level Pe, and 1 signals having width nT are recorded or rewritten using a light pulse train having a first pulse portion fp having power Pw and width xT (T: clock time), a multi-pulse portion mp in which a number (n?n?) of high level pulses each having power Pw? and width yT, and, if (n?n?)>1, a low level pulse which has power Pb and width (1?y)T are applied, and an end pulse portion ep having power Pb? and width zT, wherein n and n? are a positive integer (n>n?), and wherein each of Pw and Pw? is greater than Pe, Pe is greater than each of Pb and Pb?, and at least one of x, y and z is in a range as follows: 0.35?x?0.75, 0.30?y?0.55, 0.35?z?0.70.

Abstract: An optical disk has a multi-layer tuned optical coating overlying both small bumps to store pre-recorded information and lands onto which information is written to and read. The optical coating includes a phase-change metal/alloy layer formed over the disk substrate and a dielectric layer formed over the phase-change layer. An optical disk according to the invention has specific topological features and sizes.

Abstract: An optical disk includes at least one region along a radial direction, and a plurality of tracks provided in the at least one region. The at least one region contains address regions radially positioned on the plurality of tracks. In the address regions, data which is common between two adjacent tracks of the plurality of tracks is recorded at positions aligned along the same radial direction on the two adjacent tracks, and data which is not common between the two adjacent tracks is recorded at positions along different radial directions on the two adjacent tracks.

Abstract: A method and apparatus for write protection of rewritable compact disks and digital video disks. A Power Calibration Area is covered to prevent the drive laser from completing a calibration procedure. In one embodiment, the disk has an indented area formed around the central hole in the disk. A ring shaped plug is inserted into the indented area, with an extended surface that covers the calibration area. In an alternative embodiment, an adhesive label, ink, dye or paint is used. In still another alternative embodiment, the calibration area is mechanically abraded to provide permanent write protection. Finally, the laser in the drive may be used to darken, damage or destroy the calibration area or a transparent label over the calibration area, for permanent write protection.

Abstract: A near-field optical recording medium comprises a recording layer capable of writing, reading and erasing information using an evanescent light, the evanescent light having a beam spot size smaller than the wavelength of a source light, wherein the recording layer is a stable amorphous layer mainly comprising a photochromic compound having a glass transition point of 55° C. or higher and a molecular weight of 3000 or less.

Abstract: Disclosed is an optical disk barcode forming method wherein, as information to be barcoded, position information for piracy prevention, which is a form of ID, is coded as a barcode and is recorded by laser trimming on a reflective film in a PCA area of an optical disk. When playing back the thus manufactured optical disk on a reproduction apparatus, the barcode data can be played back using the same optical pickup.

Abstract: A photonic crystal having reversibly tunable photonic properties. The photonic crystal includes a phase change material having a plurality of structural states that vary with respect to fractional crystallinity. Optical constants including refractive index, extinction coefficient and permittivity vary as the fractional crystallinity of the phase change material is varied thereby providing tunability of photonic crystal properties. Variations among the structural states of the phase change material are reversibly effected through the addition of energy in forms including optical or electrical energy. The photonic crystals may include defects that provide photonic states within the photonic band gap. The position of these states is tunable through the control of the fractional crystallinity of the phase change material included in the photonic crystal. Electromagnetic radiation resonators including photonic crystals having photonic states in the photonic band gap are further provided.

Abstract: A phase-change optical recording medium which attains a high erasability in overwriting at a high linear velocity and has high recording sensitivity, excellent OW cycling characteristics, and excellent weatherability. The phase-change optical recording medium comprises a substrate and formed thereon a multilayered film comprising a protective layer and a recording layer and is that information is recorded/erased based on reversible phase changes in the recording layer between a crystalline phase and an amorphous phase, wherein the protective layer is a film made of an oxide of tantalum or aluminum and at least one carbide, and the content of the carbide is from 1 to 40 mol %.

Abstract: The present invention is related to methods and apparatus to produce a memory cell or resistance variable material with improved data retention characteristics and higher switching speeds. In a memory cell according to an embodiment of the present invention, silver selenide and a chalcogenide glass, such as germanium selenide (GexSe(1?x)) are combined in an active layer, which supports the formation of conductive pathways in the presence of an electric potential applied between electrodes. Advantageously, embodiments of the present invention can be fabricated with relatively wide ranges for the thicknesses of the silver selenide and glass layers.

Abstract: A recording method of a multilayer recording medium includes a first initializing step of initializing a lower recording layer based on a first initializing condition and a second initializing step of initializing an upper recording layer on the basis of a second initializing condition different from the first initializing condition. The second initializing condition is determined so that a transmittance of the recording layer after execution of the second initializing step is approximately equal to a transmittance of the recording layer after a predetermined data signal is recorded on an upper recording layer.

Abstract: A phase-change optical recording medium capable of implementing record and readout operations of information data through reversible phase transition between amorphous and crystalline states induced by light beam irradiation in a recording layer included in the recording medium, including at least a transparent substrate and contiguous layers formed on the substrate in order as follows, a lower dielectric protective layer, the recording layer, an upper dielectric protective layer, and a reflective/heat dissipating layer, in which the upper dielectric protective layer essentially consists of a mixture of ZrO2 and SiO2, having a composition of (ZrO2)100-x (SiO2)x, where 0<x<60 (mole %).

Abstract: A method for reading data from high density optical recording media is disclosed. In this method, a value is generated from a formula Pr/(&lgr;/NA), wherein Pr is light source reading power; &lgr; is wavelength; and NA is numerical aperture, when the value is in a range of about 1.15 to about 8 mW/&mgr;m, a recording mark within the high density optical recording medium which is smaller than a resolution limit of an optical system is detected.

Abstract: An optical information recording medium includes a substrate formed in a concave-convex state by providing pits or grooves corresponding to recorded information, used for optically reproducing the information by irradiation of a light beam, and may also include a recording layer. The optical information recording medium includes a temperature responsive layer whose reflectance and/or transmittance for the light beam changes with a change in temperature caused by the irradiation of a light beam. With such an arrangement, the present invention provides an optical information recording medium enabling secure and highly accurate reproduction of information recorded with high density, and the recording and reproduction methods thereof.

Abstract: A holographic data storage medium includes a data storage body and a protective layer such as an anti-UV protective layer. The data storage body is used to record a holographic data such as a hologram or a holographic image. The protective layer is formed on the surface of the data storage body. In this case, only light of specific wavelength excepting UV light is allowed to pass through the protective layer, so that the data storage body can be prevented from UV light.

Abstract: An information storage medium includes BCA marks, having unique information, formed near the outer edge of the information storage medium. The BCA marks may be formed at the outermost edge of the information storage medium. This new layout enables miniaturization of the information storage medium so that the information storage medium is applicable to portable information recording and reproduction apparatuses.

Abstract: A phase-change optical recording medium capable of performing recording and reproduction at a high speed is provided, in which a reproduced signal output is not only sufficiently large but the phase-change optical recording medium also has excellent repeated rewriting performance. An interface layer 3, which is composed of a Ge—Si—N-based material, is formed on at least a surface of one side of a recording layer 4 of the phase-change optical recording medium 10. Accordingly, even when a phase-change material having a high melting point, for example, a Bi—Ge—Te-based phase-change material is used for the recording layer 4, it is possible to provide the phase-change optical recording medium in which the reproduced signal output is sufficiently large and the repeated rewriting performance is excellent.

Abstract: A phase change optical disc that has a multilayer structure. The structure is sequentially laminated on the transparent substrate starting with a first dielectric layer; a phase control layer, the phase control layer having two areas are defined in a laser spot in which the irradiation with a reproduction beam causes a phase difference that alters the optical path of the reflected reproduction beam passing through the areas; a second dielectric layer; the phase change recording layer, which reversibly converts between a crystal phase and an amorphous phase by irradiation with a recording beam; a third dielectric layer; a reflective layer; and a protective layer. An alternative embodiment includes a fourth dielectric layer disposed between the reflective layer and the protective layer. The information of a recording mark can be accurately reproduced due to the phase difference between adjacent areas on the phase control layer, thereby reducing the size of the effective spot of the reproduction beam.

Abstract: A high-density optical disc with a super-resolution near-field structure (Super-RENS) on which information is written by a beam has multi-layers formed on a substrate. The disc includes one or more Super-RENS mask layers and one or more phase-change recording auxiliary layers, each containing a highly crystalline material. The Super-RENS optical disc allows high quality signal reproduction by eliminating signal instability and unevenness that may occur during reproduction after recording data as well as low manufacturing costs and high production yields.

Abstract: The present invention relates to an optical medium, having on at least one face (10), a superficial recording level (20) and a buried recording level (30), capable of being read and recorded by means of an optical beam having a wave length between 620 and 670 nanometers, and wherein each of the levels has a reflectivity between 6% and 12%.

Abstract: A magnetic recording medium for thermally-assisted recording is a bilayer of a high-coercivity, high-anisotropy ferromagnetic material like FePt and a switching material like FeRh or Fe(RhM) (where M is Ir, Pt, Ru, Re or Os) that exhibits a switch from antiferromagnetic to ferromagnetic at a transition temperature less than the Curie temperature of the high-coercivity material. The high-coercivity recording layer and the switching layer are exchange coupled ferromagnetically when the switching layer is in its ferromagnetic state. To write data the bilayer medium is heated above the transition temperature of the switching layer. When the switching layer becomes ferromagnetic, the total magnetization of the bilayer is increased, and consequently the switching field required to reverse a magnetized bit is decreased without lowering the anisotropy of the recording layer. The magnetic bit pattern is recorded in both the recording layer and the switching layer.

Abstract: An optical information recording medium includes a first dielectric layer composed of ZnS—SiO2, a second dielectric layer composed of silicon oxynitride, a third dielectric layer composed of ZnS—SiO2, a first interface layer composed of GeN, a recording layer composed of Ge2Sb2Te5, a second interface layer composed of GeN, a fourth dielectric layer composed of ZnS—SiO2, and a reflecting layer laminated on a transparent substrate in this order. The second dielectric layer is deposited by reactive sputtering in a mixed gas atmosphere composed of Ar, O2, and N2. The refractive index of the second dielectric layer is controlled so as to be lower than the refractive indexes of the first dielectric layer and the third dielectric layer. In the recording layer, the optical absorptivity in the amorphous state is controlled so as to be lower than the optical absorptivity in the crystalline state.

Abstract: A recording layer included in an optical information recording medium of the present invention includes: a mixture of a low oxide Te—O—M (M denotes at least one element selected from the group consisting of a metallic element, a metalloid element, and a semiconductor element) or a low oxide A—O (A denotes at least one element selected from the group consisting of Sb, Sn, In, Zn, Mo and W; and a material X (X denotes at least one compound selected from the group consisting of a fluoride, a carbide, a nitride and an oxide). Herein the low oxide refers to an oxide whose composition ratio of oxygen element is smaller than a composition ratio of oxygen element according to a stoichiometric composition.

Abstract: An optical recording medium including two or more recording layers which are capable of transmitting at a high transmittance recording light or reproducing light for performing recording/reproducing of a first recording layer (3) without having to make the thickness of a second recording film (5) positioned towards the side from which the recording light or the reproducing light enters. An optical recording medium including two or more recording layers, and which includes the first recording layer (3), the second recording layer (5) positioned further towards, with an intermediate layer (4) in between, the side from which the recording light or the reproducing light enters than is the first recording layer (3), and includes, between the above-mentioned intermediate layer (4) and the above-mentioned second recording layer (5), a dielectric layer (7) for increasing the transmittance for light passing through the above-mentioned second recording layer as the incident angle of the light becomes greater.

Abstract: The present invention provides CD-RW which makes high velocity recording at a level of at least 24-times velocity possible, rewritable DVD which makes high velocity recording at a level of at least 6-times velocity possible, and a recording method therefor, while maintaining interchangeability with conventional CD-RW standards and rewritable DVD standards.

Abstract: When initializing first and second information layers on a phase-change optical disk of the one-side multilayered configuration, a mistake occurs depending on thin film configuration of first and second information layers.

Abstract: Disclosed herein is a recording method for recording an image on a thermosensible image bearing medium that contains liquid crystal material. The liquid crystal exhibits a cholesteric phase at a temperature range higher than a room temperature so as to reflect selected wavelength of light based on heated temperature within the temperature range. Since the cholesteric liquid crystal material has a different response time for each selective reflection wavelength, an optimum energy application time is required for obtaining a desired recording color. Accordingly, in the recording method, it is getting higher the heating temperature, shorter the application time. The application time can be adjusted by the pulse width and/or pulse number of the applied energy.