Abstract: Disclosed herein is a recording medium on or from which the recording or reproduction of data is stably performed. On the recording medium, data are recorded three-dimensionally by the irradiation of a recording laser beam. The recording medium includes a reflection control layer including a plurality of reflection layers stacked in a film thickness direction, each reflection layer having a connection terminal, each reflection layer exhibiting reflectivity and transmissivity changeable in response to an electrical signal supplied to the connection terminal and a recording layer disposed at a beam incidence side of the reflection control layer.

Abstract: An optical pickup apparatus changes a propagation direction of luminous fluxes, out of a laser light reflected by a disc, in four luminous flux regions set about a laser optical axis so as to mutually disperse these luminous fluxes. A signal light region in which only a signal light is present appears on a detection surface of a photodetector. A plurality of sensors for a signal light are placed at positions irradiated with the signal light within the region. When an arithmetic process is performed on a detection signal outputted from each sensor, a DC component occurring in a tracking error signal is suppressed.

Abstract: A file system which is enabled to use a Metadata Partition instead of VAT for write-once discs, is provided by a pseudo-overwrite method. On applying this invention to a drive apparatus which supports pseudo-overwrite media, the file system distinguishes data to overwrite from data to append. When the data is newly written to a logical sector, the drive apparatus writes the data to a physical sector to which the logical sector corresponds. When the logical sector is overwritten the data is written to another unrecorded physical sector in the volume space, and remapping information that specifies the original address, and the remapping address are stored in the remapping table.

Abstract: An optical disc recording device according to the present invention is capable of quickly performing the OPC operation for a rewritable optical disc, and is also capable of setting the proper writing power for both an unwritten area and a written area. A microcomputer reads out, from a memory, preliminary writing conditions for the optical disc in question, and then performs preliminary writing so that data is written to a test writing area of the optical disc under the preliminary writing conditions. After that, test writing to the test writing area, which has been subjected to the preliminary writing, is performed with the writing power being changed, and thereby the optimum writing power is determined. Information about the writing power and the erasing power is stored in the memory on an optical disc type basis. The information is used for the preliminary writing.

Abstract: An optical disc drive apparatus (100) of the present invention rotates an optical disc (1) at a predetermined rotation speed using a motor (2). An optical pickup (3) irradiates the optical disc (1) with a laser beam (5) emitted from an internal semiconductor laser (4) included therein, and obtains a reproduction signal (7) based on a laser beam reflected from the optical disc (1). A laser driving unit (8) controls a driving current (9) of the semiconductor laser (4) to a predetermined level, and superimposes a high-frequency current (11) having a predetermined level on the driving current (9). In a high-speed reproduction mode, a control unit (12) sets the rotation speed of the optical disc (1) higher, the power of the laser beam (5) irradiating the optical disc (1) higher, and the level of the high-frequency current (11) lower than in a normal reproduction mode.

Abstract: A fabrication method of a multilayer optical recording medium having a plurality of recording layers, comprises a step of preparing an optical recording medium having at least one record area; a write-position mark generating step of recording write-position marks in the record area beforehand; a step of preparing an optical system including a common objective lens to focus a data recording beam and a position mark recording beam on different positions in a thickness direction of the record area; a first data writing step of writing data between the write-position marks with following the write-position marks by the data recording beam; a position mark recording step of, in parallel with the first data writing step, recording new write-position marks in the record area by the position mark recording beam; and a second data writing step of writing data between the new write-position marks with following the new write-position marks by the data recording beam.

Abstract: An interference-type optical pickup, an optical information detection method, and an optical information recording and reproducing apparatus, which allow easy adjustment of a path difference between two lights, have a high signal amplification effect and are suitable for size reduction of an optical system, are provided. A signal light reflected from an optical disk and a reference light branched from the same light source and guided into detectors without being projected onto the optical disk are caused to interfere with each other on detectors. Detector outputs in four interference states in which phase relationships between the reference light and the signal light are different from each other by degrees are simultaneously obtained and calculated. Accordingly, a readout signal RF that is always stable and amplified with high quality is obtained even when an optical path changes due to disk undulations.

Abstract: An optical disc apparatus according to the present invention steadily performs a focus jump operation and a track-crossing seek operation relative to an optical disc having a plurality of recording layers. A signal processing section generates a focus error signal based on a conventional astigmatism detection (CAD) system and a focus error signal based on a differential astigmatism detection (DAD) system from a detection signal generated by an optical detector. When a focus jump is to be performed from one recording layer of the optical disc to another recording layer, a focus drive signal that is generated from the focus error signal based on the CAD system is used. When a read/write operation is to be performed in relation to one recording layer, a focus drive signal that is generated from the focus error signal based on the DAD system is used.

Abstract: In a beam applying method, recording and reproducing operations are performed on an optical recording medium, in which a signal is recorded and reproduced by applying a beam thereto and which has a recording layer on which the signal is recorded, a quarter-wavelength plate formed below the recording layer, a polarizing plate formed further below the quarter-wavelength plate, and a reflecting film formed below the quarter-wavelength plate. The beam applying method includes the steps of; emitting a beam to be applied to the optical recording medium; and driving a quarter-wavelength plate inserted into an optical system serving to guide the emitted beam to the optical recording medium so that the optical axis direction thereof has a predetermined angle difference at the time of performing a recording operation and reproduction.

Abstract: An optical disc drive according to the present invention can write data on both a write-once disc and a rewritable disc. The drive includes: a disc recognizing section 110 for recognizing the type of a given optical disc as a write-once disc or a rewritable disc; and track skipping detection signal generating section, which outputs track skipping detection signal when a first condition on tracking error is satisfied if the given optical disc, on which data is being written, has turned out to be a write-once disc. On the other hand, if the given optical disc has turned out to be a rewritable disc, the track skipping detection signal generating section outputs track skipping detection signal when a second condition on tracking error, which is different from the first condition, is satisfied. A control section stops writing the data in response to the track skipping detection signal while the data is being written.

Abstract: To provide an optical head to produce good servo and read signals by reducing the influence of interference by light reflected from a non-read layer of a multilayer optical disc. The head includes: a first optical system for converging light from a light source on a first or second storage layer; a second optical system for receiving and transmitting light reflected from the first layer and stray light reflected from the second layer when the light is converged on the first layer; a photodetector; and a calculator. The photosensitive areas of the photodetector output signals representing intensities of the light incident there through the second system. The reflected and stray light incident on the second system interfere with each other, and the first and second groups of areas are arranged so as to be equally affected by a variation in intensity caused by the interference.

Abstract: According to one embodiment, an information storage medium includes an organic dye material which records information with a light beam having a wavelength equal to or smaller than 620 nm.

Abstract: An optical disc recording device includes: an optical disc device to record optical recording data onto an optical disc; a recording data assigning unit to divide a recording region on the optical disc into multiple divisions, part as a data region, assign optical recording data thereto; a redundancy data calculating unit to calculate redundancy data for restoring recorded data; a redundancy data assigning unit to take divided regions other than the data region as a redundancy region, and assign the corresponding redundancy data thereto; a recording/playing device having a recording capacity greater than the data region; and a recording control unit configured to record optical recording data in the data region and also at least a part thereof in the recording/playing device, cause the recording/playing device to play the optical recording data recorded therein at the time of calculating redundancy data, and record calculated redundancy data in the redundancy region.

Abstract: An optical disk device includes a DPDTE signal generating section that detects misalignment between a light spot and a mark or a pit, an FE signal generating section, an optical crosstalk correcting section which corrects a signal output by the FE signal generating section using the DPDTE signal generating section, and a focus control section which controls an actuator so that a light beam converges on an information layer. The DPDTE signal generating section detects the misalignment on the basis of phase information obtained from signals received from predetermined light receiving areas. The optical crosstalk correcting section performs a correcting operation of removing a signal component from predetermined receiving areas of a detector which component is used for a DPDTE signal, the signal component being contained in the signals from the predetermined light receiving areas of the detector which signals are used by the FE signal generating section.

Abstract: An optically-readable disk includes a device that disrupts readability of the disk when the disk is spun at an angular velocity substantially greater than required to play the disk in its intended playing device, or for when a defined integral of velocity and time is exceeded. The device may include a fluid container that disperses a data-disruptive fluid. The device may include a membrane or layer that is disrupted when the disk is rotated above a defined angular velocity, or when a defined integral of velocity and time is exceeded.

Abstract: In an optical element feeding device and an optical pickup unit using the same, in order to make the device compact and light and achieve a stable operation, the device has a main shaft and a sub shaft supporting a movable frame in which an optical element is arranged in such a manner as to be movable in a direction of an optical axis, a stepping motor, a lead screw rotating on the basis of a rotation of the stepping motor, a resin nut engaging with the lead screw and being movable in the direction of the optical axis on the basis of the rotation of the lead screw, and a spring pressing the movable frame in the direction of the optical axis so as to bring the movable frame into contact with the nut, and a cushioning material is provided between the nut and the movable frame so as to connect the nut and the movable frame.

Abstract: Provided is an optical disk device installed in a personal computer, including: an information creation unit that creates identification information for identifying the type of the personal computer based on a command transmitted from the personal computer; and a parameter selection unit that conducts switching, for parameter selection, concerning a parameter indicating an amount of unbalance of an optical disk, which has previously been determined depending on the type of the personal computer, in accordance with the identification information created by the information creation unit.

Abstract: An optical pickup device includes a diffraction grating 12 for separating a light beam emitted from a semiconductor laser element into at least three light beams. The diffraction grating 12 is divided into three regions by a straight line extending in a direction parallel to a tangent line of a track of an optical information recording medium. A second region 12B is divided into a first sub-block 13 and a second sub-block 14 by a straight line extending in a direction parallel to a radius direction of the optical information recording medium. The first sub-block 13 has a phase difference of approximately 180 degrees from the second sub-block 14. The first region 12A has a phase difference of approximately 90 degrees from the first sub-block 13 and has a phase difference of approximately 180 degrees from the third region 12C.

Abstract: Improved techniques for forming a reflective layer of an optical disc are provided. One improvement includes forming the reflective layer over an information layer of the disc by utilizing a metallizer and a masking device having an angled lip configured to align to an outer edge of the information layer. The masking device allows the applied reflective layer to extend to the outer diameter edge of the information layer, and shields plasma generated by the metallizer from reaching internal components of the metallizer. The masking device may include a pusher having a spring mechanism attached to an inner masking portion of the masking device.

Abstract: An optical-pickup apparatus comprising: a laser-light source; a diffraction grating including first-and-second regions of periodic structures different in phase from each other and a third region whose periodic structure is different in phase from the first-and-second regions; an objective lens focusing main-and-sub-luminous fluxes generated by the diffraction grating on the same optical-disc track; and a photodetector to receive reflected light of the main-and-sub-luminous fluxes from an optical disc and output a detection signal for generating main-and-sub-push-pull signals, a relationship between an incident light width in the objective lens corresponding to the third region and pupil diameters of the objective lens corresponding to first-and-second wavelengths of laser lights being adjusted so that a ratio of minimum value to maximum value of a differential-push-pull-signal is at substantially 50% or more and a ratio of sub-push-pull-signal level to main-push-pull-signal level is at substantially 15% or m