Abstract: On an optical disk in a recording and/or playback apparatus, the position at which the thickness error of a light transmission layer is in the optical axis of an objective lens 11, and the position at which the recording/playback of information is performed is in the optical axis of a two-group objective lens 20, so that they are spaced apart from each other, making it impossible to accurately detect the thickness error at the position where the recording/playback of information is performed. Further, to chronologically compensate for the space between them, an excess circuit is required. In view of this, a first reflection light 107a reflected by a medium surface 106a of the optical disk is received to detect the focal error with respect to the medium surface, and a second reflection light 107b reflected by the surface of a light transmission layer 106b formed on the medium surface 106a to detect the focal error with respect to the surface of the light transmission layer 106b.

Abstract: The optical data recording method comprising the steps of: modulating data to be recorded, to generate a plurality of recording modulation codes; and emitting a pulse-like light beam to an optical disc, so that a plurality of recording marks and spaces which have lengths corresponding to the plurality of recording modulation codes are formed on the optical disc. In the optical data recording method, at least two of the plurality of recording marks comprises: a first pulse which is disposed at a front and forms a leading edge of the recording mark, a last pulse which is disposed at a backend and forms a trailing edge of the recording mark, and a multi-pulse train which is disposed between the first pulse and the last pulse and forms a center of the recording mark. The multi-pulse train has a pulse period longer than T which represents a reference period of the recording modulation code.

Abstract: On an optical disk in a recording and/or playback apparatus, the position at which the thickness error of a light transmission layer is in the optical axis of an objective lens 11, and the position at which the recording/playback of information is performed is in the optical axis of a two-group objective lens 20, so that they are spaced apart from each other, making it impossible to accurately detect the thickness error at the position where the recording/playback of information is performed. Further, to chronologically compensate for the space between them, an excess circuit is required. In view of this, a first reflection light 107a reflected by a medium surface 106a of the optical disk is received to detect the focal error with respect to the medium surface, and a second reflection light 107b reflected by the surface of a light transmission layer 106b formed on the medium surface 106a to detect the focal error with respect to the surface of the light transmission layer 106b.

Abstract: An optical information storage medium includes a lead-in area, a lead-out area, and a user data area between the lead-in and lead-out areas and in which user data is recorded. Pits are formed in the lead-in area, the user data area, and the lead-out area, and a track pitch in all or a portion of the lead-in area is different from a track pitch in the remaining area of the optical information storage medium.

Abstract: A method is used for calibrating a writing power of an optical storage carrier player. The player has an access device for writing data onto the optical storage carrier. The carrier includes a center, an inner power calibration area (first calibration area), a data storage area, and an outer power calibration area (second calibration area). The method determines a writing location of the data in the data storage area, and controls the access device to perform an optical power calibration process in either the inner power calibration area or the outer power calibration area according to the writing location. Once completed, the method then utilizes a result of the optical power calibration process to determine a required writing power, and finally controls the access device to write the data to the optical storage carrier in the writing location with the required writing power.

Abstract: An optical storage device having a lens opposite to a storage medium comprises an actuator that moves the lens,a mechanical shock acceleration sensing means that senses a mechanical shock acceleration, a collision prevention control means that drives the actuator for a predetermined period of time with a first driving force greater than the maximum rating force of the actuator when the mechanical shock acceleration sensed by the mechanical shock acceleration sensing means becomes a value equal to a predetermined value, and then, that drives the actuator with a second driving force smaller than the maximum rating force of the actuator.

Abstract: Disclosed are a writing method and a disk recording apparatus for maintaining reproduction reliability relative to a rewritable disk recording medium of a zero link type. In one embodiment, a disk recording apparatus for a rewritable optical disk comprises a first timing detector having a first timing synchronized with a wobble reproduction signal of the rewritable optical disk, and a second timing detector having a second timing synchronized with a track reproduction signal of the rewritable optical disk. A phase difference detector is configured to detect a phase difference between the first timing and the second timing. A controller is configured to determine a recording area based on the detected phase difference. In another embodiment, a selector is configured to select a timing between the first timing and the second timing.

Abstract: An optical head unit is provided including a first light source emitting a light with a first wavelength, a second light source emitting a light with a second wavelength, and a third light source emitting a light with a third wavelength. The optical head unit also includes a first objective lens irradiating the light emitted from the first light source onto an optical recording medium, a second objective lens irradiating the light emitted from the second light source or the light emitted from the third light source onto an optical recording medium, and a photodetector receiving a reflected light from the optical recording medium.

Abstract: A write-once optical recording medium, and a method and apparatus for recording management information on the recording medium are provided. The method includes recording, in a temporary defect management area (TDMA), management information produced while the recording medium is in use, and transferring and recording the latest management information of the TDMA in a final defect management area (DMA) of the recording medium at a DMA fill-in stage of the recording medium.

Abstract: In order to perform simultaneous recording and reproduction, a large capacity of buffer memories were required. In addition, it was difficult to record data while reproducing data which was recorded by a different apparatus. The present invention has an objective of providing an information recording medium, a simultaneous recording and reproduction method, and an information recording and reproduction apparatus which guarantee simultaneous recording and reproduction. The simultaneous recording and reproduction is guaranteed by reproducing data recorded in an area having at least a minimum size fulfilling the simultaneous recording and reproduction condition which allows for four access operations, recording data in an area having at least the same size, and performing reproduction and recording alternately by switching reproduction to recording when the data amount in the reproduction buffer becomes full and switching recording to reproduction when the data amount in the recording buffer becomes empty.

Abstract: A thickness servo system using optical aberrations, wherein a photodetector detects an aberration amount corresponding to thickness irregularity, and a thickness irregularity correction section operates to minimize the detected aberration amount. The thickness irregularity of a transparent layer can also be calculated from the detected aberration amount.

Abstract: An apparatus and method for detecting a tilted disc, and an apparatus and method for reproducing data from the tilted disc are provided.

Abstract: An optical playback or recording device is equipped with mass-unbalance detection means (20) for detecting unbalance on the record carrier (2). Mass-unbalance causes vibration and sound in the optical device when the record carrier (2) is rotated at a relatively high speed. When mass-unbalance is detected, the speed may be reduced to reduce the vibration and sound in the optical device. The mass-unbalance detection means (20) performs the following steps to detect mass-unbalance: a) determining the maximum value Umax1 of the actuator control signal (AS) at a rotational speed ?1; b) determining the maximum value Umax2 of the actuator control signal (AS) at a rotational speed ?2; c) comparing Formula (I) with Formula (II). If these values are substantially equal, then the effect of mass-unbalance is small, otherwise the effect of mass-unbalance is too great and the speed may have to be reduced U max ? ? 1 ? 1 2 ? ? with ? ? U max ? ? 2 ? 2 2 .

Abstract: A method is provided for recording medium having a substrate on which first data and second data are recorded as a protrusion/depression pattern and a reflective layer that is provided on a surface having the protrusion/depression pattern. Laser light is radiated to the reflective layer to change the protrusion/depression pattern of the second data, and third data used for identifying the recording medium is additionally recorded at a predetermined position on the recording medium.

Abstract: An apparatus and method for branch prediction are disclosed. The branch predictor has four portions. The first includes a bimodal branch predictor in series with a local branch predictor; the second includes a global branch predictor. The first and second portions are in parallel and operate concurrently, and each provide an output received by the fourth portion. The third portion receives address data and selection data, and also provides output to the fourth portion. The fourth portion receives these outputs, and provides a branch prediction. The branch prediction is a selection of either the output from the first portion or the output from the second portion, based upon selection criteria received from the third portion.

Abstract: A data recording method according to one aspect of this invention comprises specifying a plurality of regions with different radial positions on a disk, and detecting the tilt amounts of the respective regions with respect to the optical axis of a light beam on the basis of a focus control signal used to just-focus the light beam on a recording surface of the disk, calculating tilt correction amounts for the respective regions in accordance with the tilt amounts of the respective regions, correcting a tilt of the optical axis with respect to a predetermined region on the basis of the tilt correction amount corresponding to the predetermined region, and recording data on the predetermined region while the tilt of the optical axis with respect to the predetermined region is corrected.

Abstract: The present invention shortens a time to be elapsed from a recording interruption to a recording restart, thereby realizing a reliable recording restart. In one embodiment, an optical disk apparatus comprises an optical pickup and a processor, which includes a reproduction system circuit, a speed information detection circuit, and a position detection circuit. The reproduction system circuit is configured to generate a reproduction signal used in restarting recording of the optical disk after an interruption, based on the electrical signal from the optical pickup and setting values. The speed information detection circuit is configured to detect speed information before or after an interruption of a recording on the optical disk based on the electrical signal from the optical pickup. The position detection unit is configured to detect a recording restart position and a current position of the optical disk.

Abstract: In an optical recording method and apparatus of the present invention, a driving power is applied to a light source to control emission of a light beam to a recording layer of an optical storage medium, the driving power including a sequence of mark and space portions, each mark portion having a pulse width that corresponds to a multiple of a period T of a write clock. A multi-pulse waveform of each mark portion of the driving power includes a front-end portion, a multi-pulse portion and a tail-end portion, the front-end portion having a first pulse width t1 with a high-power write level Pw and starting from a middle-power erase level Pe, the multi-pulse portion including write pulses each having a second pulse width t2 with the write level Pw and a third pulse width t3 with a low-power base level Pb, the multi-pulse portion having a duty ratio z=t2/(t2+t3), and the tail-end portion having a fourth pulse width t4 with the base level Pb and ending at the erase level Pe.

Abstract: An information recording apparatus for recording tracks includes: a rotation drive section (RDS) that supports and rotates a master disk with a resist layer; an exposure beam emitting section (EBES) deflectably applying an exposure beam to the disk to form a spot thereon; a relative movement drive section (RMDS) translating the RDS relatively to the spot in a radial direction of the disk; an emission controller supplying the EBES with an instruction for modulating an intensity of the exposure beam according to data to be recorded; and a movement controller supplying the RMDS with an instruction for moving the RDS with the rotating disk by a predetermined moving amount for each disk rotation.

Abstract: A tilt angle detection device and method which generates, as a first push-pull signal, a difference between light reception signals corresponding to two light receiving surfaces of one side of a photodetector, which are divided along the track tangent direction; generates, as a second push-pull signal, a difference between the light reception signals corresponding to two light receiving surfaces of the other side of the photodetector; and generates a tilt signal that indicates a tilt angle defined by a normal on the recording surface of the optical recording medium at a position of irradiation of the laser beam and the optical axis of the laser beam in accordance to a difference between amplitudes of the first and second push-pull signals.