Abstract: In one embodiment, a holographic data storage medium includes a substrate, a holographic recording material, and an optically detectable tracking pattern on the medium. The substrate may have first and second substrate portions. The holographic recording material may be a photopolymer, and the medium may have a sandwiched construction, where the holographic recording material is sandwiched between the first and second substrate portions. The optically detectable tracking pattern may be replicated on at least one of the substrate portions. Alternatively, the optically detectable tracking pattern may be recorded as a holographic grating in the holographic recording material. The tracking pattern may facilitate the ability to pinpoint the location of the holographic bit maps on the holographic medium to within a fraction of a micron.

Abstract: A recording/reproducing optical disk of the present invention comprises a first recording section formed on a spiral track in an area in the shape of a land, a second recording section formed on the spiral track in an area in the shape of a groove, the second recording section being adjacent to the first recording section, a first half header section in which first address information of the first recording section is recorded, and a second half header section, in which second address information of the second recording section is recorded, and which is disposed in pair with the first half header section in a zig-zag shifted manner, wherein the first half header section and the second half header section are located ahead of the first recording section to assume a first positional relation relatively to the first recording section and the first half header section and the second half header section are located ahead of the second recording section to assume a second positional relation other than the first po

Abstract: A power control device for controlling a power of a light source of an optical beam directed to an optical medium. The power control device includes a reflected light detector for detecting reflected light from the optical medium when irradiated by an optical beam which is following a track; an arithmetic unit for calculating from the reflected light a transmissivity of light transmitted from a disk surface to a recording layer or an amount of directed light on the recording layer of the medium; and power control means for controlling the power of the light source for emission based on a calculation result produced by the arithmetic unit.

Abstract: A magneto-optical record medium and a reproducing apparatus for the same allow data reproduction having good characteristics by a simple structure. The magneto-optical record medium includes a plurality of first grooves (3) each having sidewalls, at least one of which is wobbled in accordance with address information; an address mark (21) formed by changing a width of a land located between second grooves connected to the first grooves; and third grooves wobbled cyclically, formed in a data portion magnetically storing data and connected to the second grooves. The reproducing apparatus reproduces the data from the magneto-optical record medium.

Abstract: An optical disk provided with a land region and a groove region that are formed on a substrate, the land region and groove region being used as a recording track that is the medium of the recording/playback of information signal, and a pre-pit region that is formed at the boundary part of neighboring land region and groove region and is disposed every other boundary part, the pre-pit region including specific information. Characteristically, the specific information's in neighboring pre-pit regions are not aligned in the radius direction of the optical disk.

Abstract: A method of detecting a servo error, an apparatus therefor, a disk which maintains quantity of a servo error signal, a method of controlling a servo of an apparatus for recording data on and reproducing data from a disk, a method of detecting the tracking error, and a method of detecting tilt error of the apparatus.

Abstract: A disc driving apparatus and an information readout method according to the present invention realize optimum servo control of a readout unit in reading out the information from a recording medium having lands and grooves. The disc driving apparatus includes a unit for correcting tracking error signals, a unit for inverting signals corrected by the correcting unit to generate inverted tracking error signals, a unit for detecting which of the lands and the grooves the readout unit is scanning, and a unit for selecting the tracking error signals or the inverted tracking error signals according to the results of detection by the detection unit to tracking-control the readout unit by the selected signals.

Abstract: A control system for controlling tracking and seeking in an optical disc drive for optical media with a pitted premastered area that cannot be overwritten and a grooved user-writeable area that can be overwritten. The control system determines whether an optical pickup unit is over the premastered or the writeable areas of the optical media by measuring peak to peak amplitude of a tracking error signal. Gains and calibration values are selected based on whether an optical pickup unit is over the premastered or the writeable areas of the optical media. Reading from and writing to the optical media is disabled while jumping tracks. Control of jumping tracks on the optical media includes controlling: jumping a single track on the optical media; jumping a specified number of tracks every specified number of revolutions of the optical media; auto jumpbacks, and jumping in forward or reverse directions.

Abstract: Apparatus is disclosed for recovering both a data signal and a clock signal from an optical disk, in which nonconfocal detection is used to recover the data signal and confocal detection is used to recover the clock signal. The clock signal is recorded at a frequency slightly higher than the highest frequency components of the data signal, so the clock signal is not incorporated into the signal recovered by the nonconfocal data detector. The data and clock signals thereby can be recovered simultaneously from the optical disk, using just a single laser beam and objective lens.

Abstract: Information recording area of an optical disk is divided radially into a plurality of recording areas with a boundary area interposed therebetween. The boundary area is formed as either a high-reflection area that presents a higher reflection light level than the divided recording areas or a low-reflection area that presents a lower reflection light level than the divided recording areas. When an instruction is given to move an optical head from a current point to the target point over the optical disk, a seek operation is performed up to the start point of one of the divided recording areas that contains the target point, while detecting, on the basis of a variation in the reflection light level, the boundary area located between another one of the divided recording areas that contains the current point and the divided recording area containing the target point.

Abstract: A tracking control apparatus comprises an signal processing section, a lens characteristic measuring section and an optimum lens position searching section. The lens characteristic measuring section acquires a first address and second address of an optical disk. The lens characteristic measuring section successively generates offset set values so that the position of a converging lens is moved by an actuator at predetermined spatial intervals and counts the number of times both the first address and the second address are acquired. The optimum lens position searching section searches for a maximum value of the acquisition count and moves the converging lens using the actuator based on the offset set value when the acquisition count reaches a maximum value.

Abstract: In an optical pickup direction detection unit, a detector group receives return light from an optical disc and outputs a light detection electric signal, a push-pull signal generator generates a push-pull signal, and a land prepit signal generator generates a land prepit signal. Further, a direction determiner detects a direction detection signal based on a tracking error signal and the land prepit signal.

Abstract: An optical disc for recording data and having a recording area subdivided into coaxial annular zones with circular or spiral tracks. Each track within one of the zones is arranged for storing a same predetermined amount of data, and the first track of each zone stores an amount of data proportional to the radial position, resulting on average in a substantially constant density, the so called CLV (Constant Linear Velocity) density. The tracks include periodic characteristics, e.g. a wobble, which are radially aligned within each one of the zones, the periodicity indicating the track recording density for the track concerned. Hence, the data recording and reading speed can be synchronized to the periodic characteristics, whereas any cross-talk of the periodic characteristics of neighboring tracks is avoided.

Abstract: An optical disc (1) is provided with: a disc substrate (110); an information track (102, G) formed on the disc substrate spirally or coaxially around a center of the disc substrate, on which an information signal including a physical sector number is to be recorded; and a guide track (102, L) adjacent to the information track and formed on the disc substrate spirally or coaxially around the center, on which a guide signal including address information is to be recorded, wherein a readable emboss area, in which the information signal is recorded by an emboss pit, and an unreadable emboss area, in which an unreadable emboss pit to disable writing and reading the information signal, are formed on the information track, and the guide signal is not recorded on the guide track corresponding to the readable emboss area and the guide signal is recorded on the guide track corresponding to the unreadable emboss area.

Abstract: A method of detecting a servo error, an apparatus therefor, a disk which maintains quantity of a servo error signal, a method of controlling a servo of an apparatus for recording data on and reproducing data from a disk, a method of detecting the tracking error, and a method of detecting tilt error of the apparatus.

Abstract: A record carrier is described that has a servo track (4) indicating an information track (9) intended for recording information blocks. The servo track (4) has a periodic variation of a physical parameter at a predetermined frequency and modulated parts for encoding position information at regular intervals. The modulated parts start with a bit sync element and are of a data type having a data bit element or of a word sync type having a word sync element. The bit sync element, word sync element and the data bit element being modulated according to a same predetermined type of modulation of the periodic variation. The distances between all elements constituting the modulated parts are unique. Further a device for reading and/or writing the record carrier is described.

Abstract: An optical disc is described for recording data, which disc has a recording area for recording data encoded in optical marks at a recording density. The recording area has circular or spiral tracks provided with a servopattern comprising headers alternating with track portions. The headers contain position information encoded in preformed marks. The track portions comprise periodic characteristics, e.g. a wobble, to synchronize the data writing and reading operations. For reliably detecting the headers the phase of the periodic characteristics comprises a phase jump at a predetermined distance before each header.

Abstract: Tracking control is carried out by a push-pull method or by mechanical feed at the time of recording signals, and tracking control is carried out by a phase difference tracking method at the time of reproduction. Thus, a phase change type optical disk which enables phase difference reproduction and is erasable may be realized. In a phase change type optical disk having a phase difference reproduction structure, servo mechanism at the time of reproducing signals may be stably controlled by causing the reflectance of a blank portion to be higher than the reflectance of a recording mark portion.

Abstract: The present invention provides an optical disk drive capable of preventing breakdown in a transient response state, and its tracking and focus control method. The optical disk drive comprises an ODC which takes the timing of variation in signal amplitude of tracking error signal or focus error signal as process start timing to meet a demand for data recording or a demand for data reading, and a hold timing signal output circuit which generates a mask signal to hold the tracking control or the focus control in timing before or after variation of the signal amplitude.

Abstract: There is provided an information recording medium and an information reproducing apparatus capable of carrying out information reproduction and tracking control by utilizing near-field light. A data bit 12 of a convex having a section orthogonal to a tracking direction in a triangular shape is formed on an information recording medium 3 as an information unit, by scattering near-field light formed at a reproducing probe 1 at inclined faces of the data bit 12 with directionalities, fluxes of reflected and scattered light thereby are detected by reproduced light detectors 6 and 7 arranged symmetrically in a left and right direction relative to a central axis of the reproducing probe 1 along the tracking direction, a differential signal between the detected signals is outputted by a difference circuit 20 and an actuator 22 is driven by the differential signal via a tracking signal forming circuit 21 and a position of the reproducing probe 1 is controlled to carry out the tracking control.

Abstract: The present invention relates to an optical device with a variable numerical aperture (NA), which utilizes special optical properties of a liquid crystal medium. Through the design of external electrodes and a circuit control unit, the refraction index of the liquid crystal medium can be modulated by the external voltage so that the beam passing through the LCD produces diffraction. An optical device with a variable focal point is thus formed by combining this LC diffractive device and an objective lens. So the present invention provides an optical device with focal points of different numerical apertures by varying the external voltage, whereby the device can read optical disks of all specifications.

Abstract: Disclosed is an apparatus for recording and playback data into and from an optical disc having: first tracks including a wobbled track and a non-wobbled track each implemented by either a land or a groove; and second tracks each sandwiched by the first tracks and used for recording information wherein if the first track is implemented by a groove, the second track is implemented by a land and if the first track is implemented by a land, the second track is implemented by a groove. The apparatus includes a unit for radiating a beam to a particular track on the disc; a unit for detecting a beam reflected by the particular track on the disc; and a unit for controlling the radiation unit so as to have the radiation unit trace a wobbled track adjacent to the particular track in accordance with the reflected beam. The apparatus is capable of generating a tracking-error signal by using only 1 beam.

Abstract: An anti-piracy recording disk. The disk includes a main recording track which has interruptions or changes of turn. This gives rise to non-sequential reading and therefore to information which is difficult to access. The copying of such a disk by conventional means is very difficult making it possible to easily detect counterfeits or to render any copy unusable.

Abstract: An optical information storage system using optical storage media including multiple data layers or stacks wherein each of the multiple data stacks has a storage density comparable to a conventional single layer optical disk. The optical data storage system comprises an optical medium having a single dedicated servo layer and multiple data stacks which each contain an embedded servo format, a servo laser beam positioned to maintain a first focus point on the dedicated servo reference layer, a read-write laser beam positioned to maintain a second focus point on one of the data stacks, a first, dedicated servo system which provides focus and tracking error correction according to error signals generated from the dedicated servo layer, and a second, embedded servo system which provides focus and tracking error correction according to error signals generated from the data stacks.

Abstract: An optical information recording and reproducing apparatus for recording and reproducing an information signal on/from both concave portions and convex portions of guide grooves formed on a recording medium is disclosed.

Abstract: The present invention relates to an optical compact disc, on which data in a binary digital format are physically memorized as pits and lands of the disc surface along a spiral-shaped track running all along the surface of the disc. The track is scanned, during the data reading phase by the reading optical apparatus with a constant linear velocity (CLV). The track has at least one of first and second portions. The first portion of the track is scanned, during the data reading phase, with a CLV of between about 0.1 m/s and 1.2 m/s. The second portion of the track comprises a constant track pitch of between about 1.3 &mgr;m and 1.6 &mgr;m.

Abstract: Disclosed is a method of tracking control for an optical disc recorder and reproducer, which includes the steps of detecting a land/groove switching position, storing tracking error signals for a predetermined time if the land/groove switching position is detected, obtaining a mean value of the stored tracking error signals, and judging whether the mean value is larger than a predetermined permissible tracking level, and if it is judged that the mean value is larger than the predetermined tracking level, determining a direction of a track center, correcting the track center, and compensating for a DC offset.

Abstract: An optical disk comprising a substrate, and a plurality of tracks formed on the substrate, wherein the plurality of tracks include groove tracks consisting of a plurality of grooves mutually space apart by a fixed space, and land tracks consisting of areas between the groove tracks, wherein the borders between the groove tracks and the land tracks represent information using the waveforms from their wobbling patterns, wherein the period of the wobbling waveforms of the borders are constant on each border, but the wobbling waveforms of the opposite portions of the borders across the track are shifted in phase by a predetermined phase difference.

Abstract: An optical disk unit of this invention includes a defocus detecting system for detecting a defocus of an objective lens, a thickness unevenness detecting system for detecting a thickness unevenness of a transparent resin layer provided nearest the objective lens of a recording medium, and a thickness unevenness correcting mechanism for changing the focusing characteristic of light impinging upon the objective lens based on a change in the thickness of the transparent resin layer detected by the thickness detecting system.

Abstract: An optical disc in a sample servo format applicable to high density recording in which a control track area is formed without reducing format efficiency of a rewritable track area and an optical disc device that can read out control information in a short time with a simple circuit configuration are provided. For this purpose, in the optical disc, a space of a predetermined length where emboss prepits do not exist is arranged for each segment in the control track area, following a data area where control data are recorded by emboss prepits as a clock mark, wobble marks and an address mark.

Abstract: A disc player can be used in common for discs having different focus positions of an object lens with respect to a recording surface. The disc player carries out focus servo control with respect to the discs and reads out recorded information. The disc player comprises a judging device, a waveform setting device and a focus searching device. The judging device judges a type of disc set at the disc player. The waveform setting device selectively sets a predetermined waveform information in accordance with results of judgement by the judging device, from a plurality of waveform information which are held in advance for use in focus searching for the types of discs. The focus searching device generates a focus search signal based on the waveform information set by the waveform setting device, and carries out focus searching, at a time of start-up of the disc player, before the focus servo control is carried out.

Abstract: The objective of the present invention is to provide an optical disc recording and reproducing apparatus in which the target pre-format address and the recorded information can be read from the optical disc with excellent reproducibility, and the crosstalk between adjacent pregrooves can be prevented, even if the light beam is applied across adjacent information recording layers in accordance with the increase in a storage density of the optical disc.

Abstract: An optical disc 1 has spiral grooves GR formed on a data recording surface thereof and in which information is written to, and read from, both a land between the grooves and the grooves as tracks. Each track has a plurality of address areas AR1 and user areas AR2 formed thereon, and each of the address areas AR1 has embossed pits for a groove header GRH and embossed pits for a land header LH. Each of the address areas AR1 has provided in a leading part thereof a header mark area HM formed from a mirror finished surface. That is, this optical disc is of an on-land/in-groove recording type. An offset taking place in a tracking error signal and focus error signal is removed to accurately control the tracking and focus of an optical head.

Abstract: A method for generating header and transition flags using the DPD technology and an optical device using the same are disclosed. The method first sets a first and a second threshold levels. Then, the method generates a phase difference signal, i.e. starting a phase detection function to generate a phase difference signal. The method generates a first transition flag signal and a second transition flag signal, wherein the first transition flag signal is enable if the phase difference signal is greater than a first threshold level and the second transition flag signal is enable if the phase difference signal is smaller than the second threshold level. The method then generates a first header flag signal and a second header flag signal according to the transition flag signal.

Abstract: An optical information recording and reproducing apparatus for recording and reproducing an information signal on/from both concave portions and convex portions of guide grooves formed on a recording medium is disclosed.

Abstract: On an information record medium (1), information is optically recorded and reproduced while a servo control is performed with respect to the information record medium by a push-pull method. The information record medium is provided with: a record/reproduction area (DA) having a groove track (2), which is wobbled and continuously formed and on which the information is recorded and reproduced by a phase changing method by use of a light beam (B) having a wavelength of not less than 630 nm (nanometer) and not more than 680 nm; and a reproduction-dedicated area (RA) where a plurality of phase pits (PI) are wobbled and formed in advance, each having a depth of not less than 60 nm and not more than 90 nm and where only an information reproduction is possible by the light beam.

Abstract: A disk apparatus includes a DSP core, and executes processing for focal point positioning when turning on the power to the apparatus main body or exchanging the MO disk. The DSP core detects maximum and minimum values of outputs (focus error signal) of an FE signal detector circuit while moving the objective lens from an uppermost position of not contacted with a disk surface to a lowermost position. The DSP core calculates a middle position using positions of the objective lens upon fetching maximum and minimum values (uppermost and lowermost positions). Subsequently, the DSP core determines a range narrower than a range to be determined by the uppermost and lowermost positions, by the use of the middle point and amount of surface deflection of the MO disk. Then, the DSP core wobbles the objective lens within the narrow range and detects a focal point based on a level of the focus error signal.

Abstract: A very-high-density memory device which utilizes a scintillating medium for data storage. In one mode, the device operates as a read-only-memory (ROM) unit. In another mode, the device functions as a one-time-write (OTW) and then read-only-memory unit. In an exemplary embodiment, information is read at high data rates from a rotating data-storage disk or cylinder with an electron beam and sensitive photodetector. Two methods of following the data tracks on the storage medium are provided. Masks are provided for use in patterning the data or data tracks. These masks may also be used to pattern very-high-density media for other applications such as magnetic memory and optical near-field memory. A method of patterning radially-periodic structures using interferometric lithography is also provided.

Abstract: A disc-like record carrier has a machine-readable information track in which is provided record carrier control information including the actual physical diameter of the carrier.

Abstract: A disk apparatus includes a DSP core. When turning on power to the apparatus main body or exchanging the MO disk, setting processing of focus offset (offset) values is performed. The DSP core extracts fine clock mark (FCM) signals out of the reproduced signal through tracking on the land/groove. Specifically, in a range that mean value of FCM signal levels is equal to or greater than a predetermined level, FCM signal levels are detected at positions shifted left and right by a predetermined amount from a present offset value. In this manner, scanning is made throughout the range while being shifted by a predetermined amount, each time of which a difference is detected. An offset value where the difference assumes a minimum is determined as an optimal offset value. The optimal offset values are determined respectively for the land and the groove, which are switched according to a track (land/groove) upon reproduction.

Abstract: Apparatus (10) and method (100) for inscribing a clock pattern (14), detecting the clock pattern (14) optically, and using the clock pattern (14) to write a sevo pattern in an information storage unit (12), such as a computer hard drive. The clock pattern (14) is inscribed using a marking system (64), which may include a laser (66) or employ other, even non-optical, methods. The clock pattern (14) is inscribable into various locations on a disk platter (16) inside the storage unit (12), including many outside the media surface (26) conventionally used for such in data storage units. While the disk platter (16).is rotating, the clock pattern (14) is on detected using an detection subsystem (46), if desired through a transparent window (36) in a hermetically sealed housing (34) of the storage unit (12), for use in writing the servo pattern with less sector-inconsistency error and off-track error.

Abstract: An information recording method for recording information by irradiating an information recording medium with light, including steps of providing the information recording medium with a physical identification field (PID) and a data field, and utilizing a head amplifier for amplifying a detection signal in the PID field with a first gain and amplifying a detection signal in the data field with a second gain different from the first gain to record the information to the data field.

Abstract: In a recording medium which is circular and has first and second recording layers, the first and second recording layers each include one or more first tracks extending concentrically or spirally and one or more second tracks extending concentrically or spirally, each of the one or more first tracks and the one or more second tracks includes a plurality of first sectors and a plurality of second sectors, each of the plurality of first sectors includes first and second regions, each of the plurality of second sectors includes third and fourth regions, first and second grooves are formed in each of the second and fourth regions, the first and second grooves extending concentrically or spirally and oscillating sinusoidally, oscillation of the first groove has a first oscillation characteristic at a first prescribed position in the second region, oscillation of the second groove has a second oscillation characteristic at a second prescribed position in the fourth region, and the first and second oscillation chara

Abstract: A method and apparatus provide positive lens position control when reading information from a disk storing data using a first and a second encoding format. When reading the data encoded in the second encoding format, the lens is maintained in a substantially stationary radial position with respect to the disk. When the data encoded in the second encoding format has an error, the lens position is changed to find a better position for reading the data.

Abstract: A prepit detecting apparatus which uses an optical recording medium having information recording tracks on which information is recorded and guide tracks each of which guides a light beam to the information recording track and on which prepits for saving pre-information are formed such that the light beam is applied to the information track of the optical recording medium, the prepit detecting apparatus comprising: light receiving means divided into a first divided light receiving portion and a second divided light receiving portion divided along an optically parallel division line in a direction of tangent of the information tracks and arranged to receive reflected light of the light beam with which the optical recording medium has been irradiated; and a difference calculator for calculating the difference between a first read signal output from the first divided light receiving portion and a second read signal output from the second divided light receiving portion so that the prepit is detected in response

Abstract: An optical disk includes land and groove tracks which are alternately arranged, a land portion which is substantially flush with the land track and separates the groove track, a set of embossed pits which is formed in a boundary between the land portion and one of the land tracks located on two sides of the groove track in which the land portion is formed, and a record/reproduction interruption portion which is formed in a record area formed on the land track located on a side on which the embossed pits are not formed and adjacent to the land portion and on/from which no data is recorded/reproduced. Data are recorded/reproduced in units of ECC blocks each having a plurality of sectors.

Abstract: A pickup drive apparatus for recording or reproducing with respect to a recording medium such as a CD and a DVD. In the apparatus, return light produced by irradiating an optical spot is detected by a photodetector, and a push-pull signal is produced from this detection output. A tracking error signal is produced from the push-pull signal by a low-pass filter and a phase compensating circuit. A quasi-ON/OFF control signal having information of an irradiation position of the optical spot is produced from the push-pull signal by a high-pass filter, a comparator, and a single pulse generator. When the quasi-ON/OFF control signal is produced which indicates that the optical spot is positioned on a groove, the tracking error signal is outputted via switching circuits in synchronism with this signal production. A pickup is servo-controlled based on this output signal.

Abstract: An optical information recording medium according to the present invention includes at least one groove track and at least one land track allowing information to be recorded on or reproduced from the groove track and the land track, the groove track and the land track adjoining each other. The optical information recording medium further includes: an identification signal region including a pre-pit array, the pre-pit array indicating identification information concerning the groove track and the land track; and a servo control region disposed ahead of the identification signal region along the groove track and the land track, the servo control region including wobble pits positioned so as to shift to opposite sides of a center line of either the groove track or the land track.

Abstract: The invention provides an apparatus and method which allows playback of both of a first optical disc wherein the opposite side faces of a groove formed thereon are wobbled at a first predetermined frequency and a second optical disc wherein one of the opposite side faces of a groove formed thereon is wobbled at a second frequency shorter than the first predetermined frequency while the other face of the groove is formed as a flat face. In the apparatus and method, it is discriminated whether an object optical disc of playback is the first optical disc or the second optical disc, and various servo systems are switched based on a result of the discrimination.

Abstract: Disclosed herein is a disc drive apparatus for recording and reproducing data to and from an optical disc-like storage medium. The apparatus includes a wobble signal generating element for generating a wobble signal representative of information about the wobble detected based on reflected light from the optical disc-like storage medium, and a land/groove detecting element for determining, when the light beam fails to trace a specific track correctly on the storage medium, whether the emitted light beam is located on a land field or in a groove field. The land/groove detecting element further outputs a land/groove detection signal having a waveform inverted depending on whether the light beam is located on the land field or in the groove field.