80results about "Erasing involving phase-change media" patented technology

In a phase-change recording medium, a recording medium is provided with a barrier layer including Ge-N, Ge-N-O between a recording layer and a dielectric protective layer in order to prevent a chemical reaction and an atom diffusion between the recording layer and the dielectric protective layer. A barrier material can be also applied to the protective layer itself. Thereby, it is possible to considerably suppress a reduction of a reflectivity and a reduction of a signal amplitude due to the repeat of recording and erasing, such reductions being observed in a conventional phase-change optical information recording medium, and thereby the number of overwriting times can be increased.

An optical phase-change disc comprises a substrate having thereon a spiral groove or concentric grooves for guiding a focused light beam, and a layer structure including a recording layer and protective layers sandwiching therebetween the recording layer. The groove has wobble for recording ATIP (absolute time information) or ADIP (address information). The following relationship between the groove width GW, beam diameter R0 and wobble amplitude aw: 0.25< / =GW / R0< / =0.45 or 0.65< / =GW / R0; and 0.03< / =aw / GW< / =0.08 hold for preventing distortion of the groove caused by repeated overwriting operation to improve reliability of the optical disc.

A phase change optical recording medium is provided wherein the power of the laser beam per unit area required in the initialization is reduced. The optical recording medium has a phase change recording layer satisfying the relations: A.sub.I.ltoreq.8.0%, and C.sub.I / A.sub.I.gtoreq.3.0 when the medium is initialized with a light beam having a wavelength .lambda..sub.I, and said recording layer exhibits a reflectivity A.sub.I in amorphous region and a reflectivity C.sub.I in crystalline region at said wavelength .lambda..sub.I.

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 μm, 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.

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.

In a rewritable compact disc having a wobble groove on a substrate, crystal and amorphous states of a phase-change recording layer are an unrecorded / erased state and a recorded state, respectively. When the recording layer is exposed to recording light, amorphous marks assuming the recorded state are formed. At any of 2-, 4- and 8-times velocities with respect to a reference velocity (1-times velocity) whose linear velocity is 1.2-1.4 m / s, modulation m11 of a recorded signal when the recording light of approximately 780 nm in wavelength irradiates the recording layer via an optical system with NA=0.5 or 0.55 is 60-80%. A topmost level Rtop of reflectivity of the eye pattern of the recorded signal during retrieving at the 1-times velocity is 15-25%, and a jitter of the individual length of marks and inter-mark spaces during retrieving at 1-times velocity is 35 ns or less. Recording at 8-times or higher velocities is thereby realized without any risk of impairing the read-compatibility with the conventional CD-RW specifications at least at 4-times velocity.

A heater includes at least two leads, and a heating element which is formed between the at least two leads, a material of the heating element being different from a material of the at least two leads such that a location of a hot spot in the heater is controllable based on a polarity of current in the heater.

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 lambd / NA, with lambd and NA denoting the wavelength of the light used and the numerical aperture of the objective lens of the optical head, respectively.

There is provided an optical recording medium capable of preventing cross erase and increasing its recording density. The optical recording medium includes: a reflecting film; a first transparent film provided on the reflecting film; a first semitransparent film provided on the first transparent film; a second transparent film provided on the first semitransparent film; a recording film provided on the second transparent film, the recording film being capable of reversibly changing an atomic arrangement; and a third transparent film provided on the recording film. The first semitransparent film has a complex refractive index of n-k satisfying relationships of 0<n<1 and 1<k, and a product of a thickness d (nm) of the first semitransparent film and an extinction coefficient k of the complex refractive index is dxk<=44.

In an optical recording / reproducing apparatus of the present invention, a semiconductor laser driver supplies a selected one of a plurality of drive currents, including at least a first-level drive current and a second-level drive current, to a semiconductor laser to control the emission of a laser beam by the laser. A current driver selectively outputs one of a plurality of increment currents to the laser driver in response to control signals, the plurality of increment currents including a first increment current supplied to the laser driver during an automatic power control process and a second increment current supplied to the laser driver during a special power setting process. A detection unit detects a first power sample signal, at a first sampling point of a laser driving current waveform, from the laser beam emitted when the first increment current is supplied to the laser driver, and detects a second power sample signal, at a second sampling point of the waveform, from the laser beam emitted when the second increment current is supplied to the laser driver. A calculation unit calculates a derivative efficiency of the laser based on the first and second power sample signals detected by the detection unit, so that the drive currents of the laser driver, supplied to the laser, are controlled based on the calculated derivative efficiency.

Test signals are recorded on a prescribed area in an optical disc. The prescribed area is scanned by a laser beam while the power of the laser beam is changed among different DC erasing values. The different DC erasing values are assigned to the recorded test signals, respectively. The recorded test signals are reproduced from the prescribed area to obtain reproduced signals. Parameter values of the respective reproduced signals are detected. The detected parameter values correspond to the different DC erasing values, respectively. Among the detected parameter values, a detected parameter value is decided which matches a target. One corresponding to the decided parameter value is selected from the different DC erasing values. A prescribed coefficient and the selected DC erasing value are multiplied to calculate an optimum level of an erasing power of the laser beam.

Initialization nonuniformity due to interference of light which occurs during an initialization process is reduced without causing degradation in the characteristic of signals recorded / reproduced on / from respective recording layers. A multilayer optical disk comprising at least a first information recording layer and a second information recording layer formed, on a substrate, into a multilayer structure with an intermediate layer disposed therebetween is illuminated with initializing light from the side of the first information recording layer to initialize the first information recording layer formed of a phase-change material serving as a recording material. The illumination with the initializing light is performed such that the numerical aperture NA of an objective lens used for illumination with the illuminating light, the longitudinal length L of the beam size of the initializing light, the thickness D of the intermediate layer, and the ratio R1 of the amount of light striking the first information recording layer after passing through the first information recording layer and being reflected by the second information recording layer to the amount of light incident on the first information recording layer satisfy the following relation for a wavelength lambdi of the initializing light: LxR1<=25[1-exp(-0.0004xNA4xD2)].

There are provided an optical disk, a magneto-optical disk, a disk apparatus therefor, and a data recording method which can provide improved recording / reproducing characteristics and record durability without linear velocity dependency even if the data access speed is increased by increasing the channel clock frequency. In a disk device for recording data on an optical disk by using a phase change recording scheme, erasing means for erasing data on the optical disk, and recording means for recording other data on the optical disk after the data is erased are provided.

An information recoding medium having a substrate (32) and a recoding layer (30) whose optical property is changed by being irradiated by a laser beam to display or erase a visible display pattern.

A phase-change optical information recording medium in which information can be recorded, erased, and read includes a substrate and a recording layer overlying the substrate. The recording layer achieves a crystal phase and an amorphous phase. The absorptance Ac of the recording layer in the crystal phase against light having a wavelength of from 370 nm to 450 nm is lower than the absorptance Aa of the recording layer in the amorphous phase against the light. Information is recorded on the recording medium with a recording wavelength of from 370 nm to 450 nm at a recording pitch of 0.3 μm to 0.52 μm.

A recording medium is provided that has at least a recording layer on a transparent substrate. The recording layer has at least a first phase-changeable film and a second phase-changeable film in that order, starting on the side closest to the transparent substrate. The first phase-changeable film and the second phase-changeable film each contains at least 10 atom % and no more than 50 atom % germanium and at least 45 atom % and no more than 60 atom % tellurium. Also at least one of the phase-changeable films contains bismuth.

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 μm, 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.

A method and apparatus to record data on an optical recording medium include generating a recording waveform having an erase pattern comprising a multi-pulse having a high level which is higher than an erase power level and a low level which is lower than the erase power level. A power level of a leading one of the multi-pulse of the erase pattern and a power level between an end of the erase pattern and a start point of a leading pulse of a recording pattern are controlled to be the low level and the high level, respectively, the high level and the high level, respectively, the high level and the low level, respectively, or the low level and the low level, respectively.

An optical data recording method for recording data in a phase-change optical recording medium using a sequence of one or more short pulses is provided. In this method, a temperature is detected at a prescribed spot around the optical recording medium. The amplitude of the short pulses is controlled in response to the detected temperature. Then, data are recorded in the optical recording medium using the sequence of amplitude-controlled short pulses.

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.

A first laser beam and a second laser beam are selectively generated. The first or the second laser beam is irradiated on an optical storage medium having a recording layer on which main data has been recorded. The main data includes data to be reproduced and reproduction management data. The laser beam selection is made according to the reproduction management data. The first laser beam has a first laser power capable of carrying the main data without erasing when reflected from the optical storage medium. On the other hand, the second laser beam has a second laser power capable of erasing the main data from the optical storage medium while carrying the main data when reflected from the optical storage medium. The data to be reproduced and carried by the first or the second laser beam is then reproduced.