Abstract: In order to ensure a favorable recording characteristic for a write-once recording medium whose recording layer is made of an organic dye having an absorption spectrum at a wavelength ?=405 nm, this optical information recording apparatus includes a unit to set a write power to form recording marks, a space forming power to form spaces and a pulse width of a cooling pulse, and a unit to record information onto the recording medium according to the setting. The pulse width of the cooling pulse and a ratio of the space recording power to the write power are determined from a favorable region in a plane whose one coordinate axis represents the ratio and whose other coordinate axis represents the pulse width of the cooling pulse.

Abstract: In a head for thermal assisted magnetic recording device, a semiconductor laser is mounted so that the total height of the head does not become larger and light power fluctuation due to wavelength fluctuation occurs less frequently. In addition, the rise in temperature of the mounted semiconductor laser is suppressed. A semiconductor laser is placed on a side surface which is different from surfaces on an inflow end side and a trailing side, of four side surfaces of a floating slider. An entrance of a waveguide is placed on the side surface of the floating slider, to thereby cause emitted light from the semiconductor laser to directly enter the waveguide. A curved line part or a reflective mirror is formed in the middle of the waveguide so that the light which has entered the waveguide travels toward an optical near-field generating element.

Abstract: A recording medium includes: at least one recording layer on which information is recorded by multi-photon absorption; and a servo layer disposed in a laminated direction with respect to the recording layer and having a track for guiding a beam spot of laser light having a first wavelength and a beam spot of laser light having a second wavelength along a scanning trajectory, wherein the servo layer and the at least one recording layer constitute a set of layers, and a plurality of sets of layers is formed in the laminated direction.

Abstract: The apparatus comprising a pickup for reading data from or writing data to an optical storage medium, wherein the pickup comprises a laser providing a laser beam, an objective lens for focusing the laser beam onto the optical storage medium, a first detector and a beam splitter arranged between the laser and the objective lens for guiding light reflected from the optical storage medium onto the first detector. A selecting means, arranged in front of the beam splitter, with regard to the reflected light from the optical storage medium, is provided for guiding reflected light passing through an outer section of the objective lens onto a second detector. The light guided onto the first detector is utilized for providing a tracking error signal and the light guided onto the second detector is utilized for providing a data signal.

Abstract: A photodetector comprising: a substrate; a photodiode fixed to the substrate, the photodiode configured to output a signal according to a light amount of a laser beam when applied with the laser beam; and a translucent resin covering the photodiode, the translucent resin being irradiated with ultraviolet light in advance for a predetermined time such that a change in transmittance of the translucent resin for the laser beam having a predetermined wavelength is set within a predetermined range.

Abstract: Stable interlayer jump is realized by judging whether a signal is a false signal caused by noises, stray light, or interference of an adjacent layer or a true FE signal.

Abstract: An optical disc playback device is capable of being transitioned to a sleep mode in consideration of an optical disc status or an optical disc drive device status. An optical disc playback apparatus includes a main controller to transmit a sleep mode transition command to an optical disc drive device, and an optical disc drive device controller to check either a status of an optical disc or a status of the optical disc drive device when the sleep mode transition command is transmitted to the optical disc drive device, and to determine whether to perform transition to the sleep mode in response to the optical disc status or the optical disc drive device status.

Abstract: A waveform shaping portion receives a digital reproduced signal generated from an analog reproduced signal reproduced from an information recording medium and shapes the waveform of the digital reproduced signal. A maximum likelihood decoding portion applies maximum likelihood decoding to the digital reproduced signal in the shaped waveform and generates a binarized signal indicating the result of the maximum likelihood decoding. A phase detection portion extracts, during the maximum likelihood decoding, a phase error using state transition patterns having only a single zero cross point among differential metrics at a plurality of merging points at which a set of paths branched from a given state merges. A synchronization detection portion generates a reproduction clock signal using the phase error that has been detected and brings the digital reproduced signal into synchronization with the reproduction clock signal that has been generated.

Abstract: The disclosure discloses a compensation method in a radial direction on a label side of an optical disc. An optical disc is inserted into an optical disk drive. The data side of the optical disc is divided into at least one compensation area. An optical pick-up head (OPU) is moved from inner to outer rings by simulating a writing process. The OPU is moved to some pre-determined points and radial-directional compensation is performed to obtain radial-directional voltage gains at the pre-determined points. The voltage gains are recorded. The label side of an optical disc is inserted into the optical disk drive. The simulated track number is calculated on the basis of the required moving distance for the OPU to write pattern on the label side. The OPU is moved to write the label side by a radial-directional lens driving voltage compensated with a gain obtained from a compensation formula.

Abstract: An object of this invention is to improve stability of tracking control and improve recording and reproduction performance. The tracking control device comprises a main push-pull signal generation section, which generates a main push-pull signal based on a signal obtained by photoelectric conversion of return light of the main beam; a microcomputer, which detects an other-layer stray light signal component included in a signal obtained by photoelectric conversion of return light of the sub-beam; a signal correction section, which corrects the signal obtained by photoelectric conversion of the return light of the sub-beam, based on the other-layer stray light signal component; and a sub-push-pull signal generation section, which generates a sub-push-pull signal based on the corrected signal obtained by photoelectric conversion of the return light of the sub-beam.

Abstract: An objective lens actuator comprises, two objective lenses, each for focusing lights upon an optical disc, an objective lens holder member for holding the objective lenses thereon, and lens protectors for preventing the objective lenses from being contacted on the optical disc, wherein the lens protectors include first and second lens protectors, which are provided on both end portions of the objective lens holder member in a tracking direction, and a third lens protector, which is provided in a middle of the two objective lenses, wherein the first and second lens protectors, which are provided on both end portions of the objective lens holder member in the tracking direction, are provided the objective lenses and end portion of the objective lens holder member in the tracking direction, and the third lens protector, which is provided between the objective lenses, has a height closer to that of the optical disc than the protectors, which are provided on both end portions of the objective lens holder member in

Abstract: An optical disc recording medium is irradiated with laser light having a predetermined laser power to deform an irradiated portion of a substrate into a protruding portion. Since the substrate is deformed so as to have protruding portions, a reflecting layer arranged on the substrate is also deformed so as to have protruding portions. For a pit, the deformed state of a protruding portion allows to obtain a reproduced signal level equivalent to that in each land. For a land, the deformed state of a protruding portion allows to obtain a reproduced signal level equivalent to that in each pit. Since the deformed state of each protruding portion can be controlled on the basis of the power of the laser light for irradiation, pit-to-land deformation and land-to-pit deformation can be performed by setting the laser power. Thus, recorded data can be rewritten on the optical disc recording medium recorded with the data using a combination of pits and lands formed in the substrate.

Abstract: In a recording method for recording information on an optical recording medium (500) according to the parameters of a write strategy by repeatedly recording (S23) a certain amount of information onto the optical disc (500) and entering a standby state (S22) in which recording is suspended and data are stored in a buffer memory (190), during an interval while recording is suspended, the information recorded just before is reproduced, the quality of the reproduced signal is measured (S25A), and the write strategy is altered as necessary (S25C) to obtain consistent recording quality. Only one correction is made per suspension period. Consistent recording quality is thus obtained despite changes in the recording position on the optical disc or changes in recording conditions.

Abstract: A recording/reproducing apparatus (100) is provided with: a first substrate (41) on which a recording medium (43) is mounted; and a second substrate (21) to which a recording/reproducing head (23), which performs information recording and information reproduction on the recording/reproducing medium is fixed, wherein the second substrate is relatively displaced in a predetermined direction substantially parallel to the first substrate with respect to the first substrate, a particulate (30) is placed in a gap between the first substrate and the second substrate, the particulate can be displaced with displacement of the second substrate, the particulate has a substantially circular cross section in a direction that the second substrate is displaced when the second substrate is displaced.

Abstract: An optical disc 1 includes a defect management area (DMA). A plurality of defective area lists (TDFLs) and structure information (TDDS) are recorded in a temporary defect management area (TDMS) of the defect management area (DMA). The defective area lists (TDFLs) indicate at least one defective area which was detected during an access to the optical disc 1. The structure information (TDDS) includes a plurality of pieces of position information that indicate positions of the defective area lists (TDFLs). The plurality of pieces of position information, corresponding one-to-one to the defective area lists, are arranged in the structure information (TDDS) in an order in which the defective area lists (TDFLs) corresponding thereto are read out.

Abstract: When an optical disk image forming device forms an image on an optical disk, the image forming device reads information of kinds of coloring matters used in an image forming area from information described in an information area of the optical disk. Then, the optical disk image forming device reads from a table laser power strength information corresponding to the information of the kinds of the coloring matters and a maximum linear velocity (Nx) at the time of forming the image and applies a laser beam having this laser power strength to form the image on the image forming area of the optical disk. Thus, since the discoloration of the coloring matter in the image forming area is always saturated, the image having a constant contrast can be formed on the image forming area of the optical disk.

Abstract: An optical disc 1 includes a defect management area (DMA). A plurality of defective area lists (TDFLs) and structure information (TDDS) are recorded in a temporary defect management area (TDMS) of the defect management area (DMA). The defective area lists (TDFLs) indicate at least one defective area which was detected during an access to the optical disc 1. The structure information (TDDS) includes a plurality of pieces of position information that indicate positions of the defective area lists (TDFLs). The plurality of pieces of position information, corresponding one-to-one to the defective area lists, are arranged in the structure information (TDDS) in an order in which the defective area lists (TDFLs) corresponding thereto are read out.

Abstract: An objective lens actuator comprises a lens holder for attaching an objective lens thereon, a piece of focusing coil, being wound along side surface of the lens holder around the objective lens, and three magnets, being disposed opposing to two surfaces each having a normal line perpendicular to both a focusing direction and a tracking direction, among four side surfaces of the lens holder, wherein the three magnets are aligned, continuously, along the tracking direction, differing a polarity thereof from one another, and width of the magnets on both outsides is wider than width of the magnet inside, or alternately, one magnet, being disposed opposing to two surfaces each having a normal line perpendicular to both a focusing direction and a tracking direction, among four side surfaces of the lens holder, wherein the magnet is magnetized into three poles along the tracking direction, and among the three poles, width of the poles on both outsides is wider than width of the pole inside.

Abstract: A grating portion has a plurality of convex portions provided on at least one principal plane of a transparent substrate having a first layer containing a first transparent material and a second layer containing a second transparent material, and extended in parallel to each other in a first direction as well as periodically arranged in a second direction orthogonal to the first direction. A filling portion fills a third layer containing a third transparent material at least between the plurality of convex portions. Assuming that the change rate of the refractive index with the change of temperature of the first transparent material is ?A, the change rate of the refractive index with the change of temperature of the second transparent material is ?B, and the change rate of the refractive index with the change of temperature of the third transparent material is ?C, the relationship ?A<?C<0 and |?C|>|?B| is satisfied.

Abstract: An objective lens driving device includes a lens holder (3) holding an objective lens (1, 2), a stationary part (5) that supports the lens holder (3) via wires (7a, 7b), an electromagnetic coil (11a-11d, 12a-12d) provided on the lens holder, and a magnet (4a, 4b) provided on the stationary part and magnetized in a multipolar manner so that different magnetic pole surfaces are arranged on a surface of the magnet facing the electromagnetic coil. The lens holder has a convex portion (16a-16d, 17a-17d) on a surface thereof facing the magnet. The convex portion has at least one groove (601-604, 701-704) portion extending parallel to a direction of magnetic flux lines of the magnet facing the convex portion, and at least a surface of the convex portion is formed of material having magnetic property.