Abstract: A signal recording/playback apparatus includes a recording data converter. The recording data converter converts on a data pattern having a large influence on adjacent tracks on an optical disk, and outputs the converted data to an optical pickup. Specifically, by performing a data converting process in which, for a data pattern having a predetermined length of at least consecutive bits having identical values, part of the bits is inverted based on a conversion table, the recording data converter compensates a recording operation. Alternatively, instead of inverting the bits, by controlling the output power and pulse width of a laser, the recording operation is compensated. The signal recording/playback apparatus includes a played-back data converter. In the data playback mode of the signal recording/playback apparatus, the data converted by the recording data converter is identified and decoded into the original data by the played-back data converter. The played-back data converter outputs the original data.

Abstract: A magneto-optical recording medium includes a first magnetic layer (reproduction layer), a second magnetic layer (control layer), a third magnetic layer (blocking layer), and a fourth magnetic layer (recording layer) having respective Curie temperatures TC1, TC2, TC3 and TC4. The Curie temperatures of the layers satisfy the relationships TC1>TC3>TC2 and TC4>TC3. In addition, the magnetic anisotropy of the third magnetic layer Ku3 is greater than that of the second magnetic layer Ku2. A magnetic domain wall in the first magnetic layer in front of the spot irradiated by the reproduction light in the direction of travel is displaced toward the peak temperature portion so that a recorded domain is expanded. Displacement in the spot direction of a domain wall in the first magnetic layer behind the reproduction light spot in the direction of travel is suppressed. The second and third magnetic layers control the magnetic exchange coupling between the first and fourth magnetic layers.

Abstract: An optical recording medium having a wobble desirably arranged in a production process when having wobble at part of interfaces of lands and grooves is provided. An optical recording medium comprising an approximately disk-shaped disk substrate 15, formed in its surface with trenches 15a and having projections and recesses divided for every track region by the trenches 15a, on which are stacked an optical recording layer 16 having relief shapes corresponding with the trenches 15a and a protection film 17 and of a format where both regions of the projections (lands L) and the recesses (grooves G) are used as recording regions etc., wherein wobble W for providing clock information or address information is formed, between a pair of facing side walls forming each trench 15a, in a side wall portion at an inner circumferential side of the disk substrate 15 when seen from the recess (groove G) and at an outer circumferential side of the disk substrate 15 when seen from the projection (land L).

Abstract: The present invention is directed to an annealing apparatus adapted for performing anneal processing with respect to a magneto optical recording medium, which comprises a diffraction optical unit (3) for optically separating light beams emitted from a laser light source (1) into first light beams which are the 0 (zero)-th order diffracted light beams and second and third light beams which are the first order diffracted light beams, an object lens (5) for converging the first light beams to irradiate the first light beams thus converged onto magnetic layers of guide grooves or land portions forming both sides of the guide grooves, and for converging the second and third light beams to irradiate the second and third light beams thus converged onto magnetic layers in the vicinity of the boundary portions between guide grooves and land portions, and a biaxial actuator unit (6) for controlling the object lens (5) on the basis of linear characteristic of a first tracking error signal generated on the basis of inten

Abstract: A magneto-optical recording/reproducing method is disclosed which causes a laser beam to be emitted to a disc recording medium having information recorded thereon earlier by magnetic field modulation, the laser beam causing the disc recording medium to develop a temperature distribution such as to generate a driving force for moving a domain wall of a magnetic domain in the medium so that the magnetic domain smaller in diameter than a spot of the laser beam is expanded sufficiently to let information recorded in the domain be detected. The method comprises the steps of: recording information to the disc recording medium while rotating the medium in a first rotating direction; and reproducing the information that was recorded to the disc recording medium in the recording step while rotating the medium in a second rotating direction reverse to the first rotating direction.

Abstract: An optical recording medium in which deposition of impurities or damage to a surface of the medium illuminated by the light for signal recording and/or reproduction is to be prevented from occurring. An amine salt compound of perfluoropolyether having terminal carboxylic groups, represented by the chemical formulas (1) and/or (2): Rf—COO?N+HR1R2R3??(formula 1) R1R2R3N+H?CO—Rf—COO?N+HR1R2R3??(formula 2) where Rf denotes a perfluoropolyether group and R1, R2 and R3 denote hydrogen or a hydrocarbon group, is held on the surface side illuminated by light.

Abstract: The present invention provides an optical disk drive and optical disk playback method, with an improved capability of reading address information from an optical disk having address information recorded thereon by wobbling one of side walls of a recording track, with a wider tilt margin.

Abstract: An optical recording medium in which deposition of impurities or damage to a surface of the medium illuminated by the light for signal recording and/or reproduction is to be prevented from occurring. An amine salt compound of perfluoropolyether having terminal carboxylic groups, represented by the chemical formulas (1) and/or (2): Rf—COO?N+HR1R2R3??(formula 1) R1R2R3N+H?CO—Rf—COO?N+HR1R2R3??(formula 2) where Rf denotes a perfluoropolyether group and R1, R2 and R3 denote hydrogen or a hydrocarbon group, is held on the surface side illuminated by light.

Abstract: An optical head is used to record and playback information to and from a magneto-optical storage medium having a displacement layer, a disconnecting layer, and a recording layer that are stacked in this order. The displacement layer is defined by a perpendicular magnetic film that is relatively smaller in domain-wall coercivity and that is greater in domain-wall mobility than the recording layer and the disconnecting layer is defined by a magnetic layer that is lower in Curie temperature than the displacement layer and the recording layer. An optimum offset value is set for causing tracking of the optical head to a recording track provided on the magneto-optical storage medium.

Abstract: In reproduction from a magneto-optical recording medium by the domain wall displacement detection method, it is possible to avoid occurrence of ghost signals and to improve dropout, and moreover design of magnetic layers is made easy. A configuration is adopted having at least, in order from the side of incidence of laser light for reproduction, a first magnetic layer 11 constituting a reproduction layer, a second magnetic layer 12 constituting a control layer, a third magnetic layer 13 constituting a blocking layer, and a fourth magnetic layer 14 constituting a recording layer, which if the respective Curie temperatures thereof are TC1, TC2, TC3 and TC4, satisfy the relations TC1>TC3>TC2 and TC4>TC3. At the same time, if the magnetic anisotropy of the second magnetic layer is Ku2 and the magnetic anisotropy of the third magnetic layer is Ku3, the relation Ku3>Ku2 is satisfied.

Abstract: A method for manufacturing a magneto-optical recording medium in which reading of recorded information is performed through domain wall displacement in a reproduction layer is provided, in which magnetic separation of groove side-wall portions is performed more reliably; as a result a magneto-optical recording medium with satisfactory recording and reproduction characteristics can be provided.

Abstract: In a manufacturing method of a magneto-optical recording medium formed by laminating a plurality of magnetic layers, there is provided a manufacturing method whereby at least two of the magnetic layers can be properly and individually formed by sputtering the same target means in the same vacuum vessel under different conditions at the time of a sputtering process in accordance with an element composition ratio and/or magnetic characteristics of each layer.

Abstract: In a DWDD (Domain Wall Displacement Detection) optical recording medium of a land and groove recording system, characteristics of a land and a groove can be well equilibrated by selecting a depth d (nm) of a groove 3 of an optical recording medium so as to satisfy the following equation:

Abstract: A phase error detection apparatus and method is disclosed whereby a data signal is played back at a high S/N ratio from a magneto-optical disk making use of a ghost signal by magnetic domain wall displacement detection while the playback laser poser is kept at an optimum level. First, the laser power is controlled so that the time delay of a ghost signal from a data signal may be equal to a fixed multiple of a data detection clock. Thereupon, a laser power control section searches for a point at which the amount of jitters generated is small based on a RF signal. Then, the playback laser power is adjusted so that the time delay amount of the ghost signal from the data signal may be the fixed multiple n=5 of the clock nearest to the phase delay amount set in advance of a ghost which appears in the isothermal region with a laser power with which an optimum signal characteristic is obtained.

Abstract: According to the present invention, when a land-groove recording method is adopted, thermal crosstalk between a land and an adjoining groove is suppressed effectively. Inhomogeneity of a recording layer between the land and groove is suppressed effectively. A substrate for optical recording media comprises groove-like concave parts (2) and convex parts each created between adjoining concave parts. A border sidewall (4) between a concave part and an adjoining convex part (2) has a plurality of sidewall planes, that is, at least a first sidewall plane (41) that leads to the bed of the concave part and a second sidewall plane (42) that leads to the apical plane of the convex part. The first sidewall plane meets the bed of the concave part at an angle ranging from 120° to less than 180°. The second sidewall plane meets the bed of the concave part at an angle ranging from 90° to 110°.

Abstract: An optical recording medium having a wobble desirably arranged in a production process when having wobble at part of interfaces of lands and grooves is provided. An optical recording medium comprising an approximately disk-shaped disk substrate 15, formed in its surface with trenches 15a and having projections and recesses divided for every track region by the trenches 15a, on which are stacked an optical recording layer 16 having relief shapes corresponding with the trenches 15a and a protection film 17 and of a format where both regions of the projections (lands L) and the recesses (grooves G) are used as recording regions etc., wherein wobble W for providing clock information or address information is formed, between a pair of facing side walls forming each trench 15a, in a side wall portion at an inner circumferential side of the disk substrate 15 when seen from the recess (groove G) and at an outer circumferential side of the disk substrate 15 when seen from the projection (land L).

Abstract: A magneto-optical recording/reproducing method is disclosed which causes a laser beam to be emitted to a disc recording medium having information recorded thereon earlier by magnetic field modulation, the laser beam causing the disc recording medium to develop a temperature distribution such as to generate a driving force for moving a domain wall of a magnetic domain in the medium so that the magnetic domain smaller in diameter than a spot of the laser beam is expanded sufficiently to let information recorded in the domain be detected. The method comprises the steps of: recording information to the disc recording medium while rotating the medium in a first rotating direction; and reproducing the information that was recorded to the disc recording medium in the recording step while rotating the medium in a second rotating direction reverse to the first rotating direction.

Abstract: An optical disc and its manufacturing method in which humps may be prohibited from being formed on an outer rim area of the disc to assure optimum surface properties of a light transmitting layer of the disc to contribute to further increase in recording capacity. On a substrate 2 of an optical disc 1 are sequentially formed a recording portion 6 and a light transmitting layer 5. The light falls on the light transmitting layer 5 to record and/or reproduce information signals for a signal recording area 6a of the substrate 2. The radial distance D from the outermost rim of the substrate 2 to the signal recording area 6a is selected to be larger than the radial width L of a hump 5a formed on the outer rim of the light transmitting layer 5. The hump 5a has a height h from the surface of the light transmitting layer 5 not larger than 70 &mgr;m.

Abstract: A signal recording/playback apparatus includes a recording data converter. The recording data converter converts on a data pattern having a large influence on adjacent tracks on an optical disk, and outputs the converted data to an optical pickup. Specifically, by performing a data converting process in which, for a data pattern having a predetermined length of at least consecutive bits having identical values, part of the bits is inverted based on a conversion table, the recording data converter compensates a recording operation. Alternatively, instead of inverting the bits, by controlling the output power and pulse width of a laser, the recording operation is compensated. The signal recording/playback apparatus includes a played-back data converter. In the data playback mode of the signal recording/playback apparatus, the data converted by the recording data converter is identified and decoded into the original data by the played-back data converter. The played-back data converter outputs the original data.

Abstract: A transaction managing portion 2, a copyright owner 3 of digital data, a user 4 of digital data, and a transaction intermediary 5 who intermediates transactions are connected through a communication network using the Internet. The transaction managing portion 2 stores digital data, encryption key data, chronological change of the circulation number of the encryption key data, chronological change of the number of transactions, identification information of the transaction intermediary 5 and the user 4, and so forth. In addition, the transaction managing portion 2 decides whether or not transactions are concluded corresponding to the number of demanded digital data and the number of supplied digital data supplied through the communication network, identification information and asset information of people concerned with the transactions, identification of encryption key data, and so forth and performs data distributing and charging processes and so forth.