Abstract: An optical disc playback method is provided which includes steps of reading identification data recorded in an optical disc loaded in an optical disc player and starting reading data from a second recording area of the optical disc loaded in the optical disc player when it is determined that the loaded optical disc is a one having at least a first recording area and second recording area, a first lead-in area provided along the inner circumference of the first recording area, a second lead-out area provided along the outer circumference of the first recording area, a second lead-in area provided between the outer circumference of the first lead-out area and second recording area, and a second lead-out area provided along the outer circumference of the second recording area.

Abstract: A method and apparatus for generating an optimum recording power before recording user data in a recordable optical recording medium is disclosed. According to the method and apparatus, an optimum power calibration (OPC) is performed in the unit of a sector, and the start position of the respective physical sector can be synchronized. Thus, the optimum recording power can be determined even in a DVD-R/RW in which a PCA area exists but no OPC method is prescribed. Also, the degree of OPC can be heightened, and the limitation of the PCA area can be overcome. The method and apparatus also enables an easy and accurate search of the start position even in an odd sector where LPP data is recorded in odd positions.

Abstract: An information recording medium in which bottoms of a guide groove and a pit array formed on a disc substrate are allocated on a same flat plane and shaped in flat. Further, in a transition area from a pit array to a guide groove or from a guide groove to a pit array, the information recording medium is provided with an intermediate area composed of a pit array of which height changes from a height between a bottom and a side of a groove to another height between the bottom and a side of the pit array.

Abstract: An optical scanning device (21) is for scanning with a radiation beam a substantially circular track of an information layer (22). The device includes: (i) a radiation source (26) for providing the radiation beam (34), (ii) a lens system (27) for transforming the radiation beam to a scanning spot (38) in the information layer, the lens system including a first objective lens assembly (39) having an optical axis (CC?), (iii) a head rotation unit (59) for the first objective lens assembly which is rotatable about an axis of rotation (BB?), and (iv) first driving means (60) for rotating the head rotation unit about the axis of rotation. The center of curvature of the track substantially coincides with the axis of rotation. According to the invention, the objective lens assembly is movable substantially in a radial direction with respect to and perpendicular to the axis of rotation.

Abstract: An information recording medium in which bottoms of a guide groove and a pit array formed on a disc substrate are allocated on a same flat plane and shaped in flat. Further, in a transition area from a pit array to a guide groove or from a guide groove to a pit array, the information recording medium is provided with an intermediate area composed of a pit array of which height changes from a height between a bottom and a side of a groove to another height between the bottom and a side of the pit array.

Abstract: In an initial operation of an optical disc apparatus for reading out information data recorded in the innermost data recording area on the optical disc, a main processor judges whether periods between adjoining two pits are normal or not from signals outputted from an optical pickup. When the periods of the pits are normal, a light beam emitted from the optical pickup is on the present data recording track, and the information data is read out from the optical disc. Alternatively, when the periods of the pits are abnormal, the optical pickup is moved inwardly with sensing the periods of the pits and judges whether the periods are normal or not. When the periods of the pits become normal, the light beam is precisely tracked on the present data recording track, and reproduces the information data from the optical disc.

Abstract: A storage medium is provided having a relatively large number of relatively small servo sectors. The storage medium includes a plurality of tracks. Each track includes a plurality of data sectors and a plurality of servo sectors. Each servo sector includes a plurality of servo marks and a synchronization gap. A plurality of first servo sectors includes a synchronization gap having a first length and a plurality of second servo sectors includes a synchronization gap having a second length. The first length is different from the second length, whereby, an unsynchronized reading device may recognize the longer synchronization gap and synchronize to the servo sector and a synchronized reading device may remain synchronized by recognizing the shorter synchronization gap.

Abstract: An optical pickup apparatus having an irradiation optical system for condensing a light beam on a track of a recording plane and a photodetection optical system for guiding return light to a photodetector to detect a focal error includes a holographic lens provided in the optical path of the return light for outputting 0-th and ±1st order diffracted lights based on the return light; an optical element provided in front of or behind the holographic lens for providing astigmatism; photodetectors for receiving the 0-th and ±1st order diffracted lights; and servo-signal generating operation circuits connected to the photodetectors for generating a first and second focus error signals having a first and second capture ranges based on the output signal of the photodetector.

Abstract: An optical recording/reproducing apparatus comprises a light beam emitting unit which emits a plurality of light beams to the recording medium, a photodetection unit which detects the reflected light beams and output detection signals, a detection signal selection unit which selects one of the detection signals according to one of a plurality of tracks which is selected in order to record or reproduce data, the tracks being formed on at least one of the land and the groove, and a tracking control unit which make one of the light beams trace the track which is selected in order to record or reproduce data, according to the selected detection signal.

Abstract: An information recording medium having at least a read only area and a recording and reproducing area is composed of at least: a substrate; a recording layer formed on the substrate so as to record and reproduce information; and a light transmission layer having transparency formed on the recording layer. The information recording medium is further characterized in that a wobbling groove corresponding to the read only area and another wobbling groove corresponding to the recording and reproducing area is formed on the substrate without overlapping with each other, the recording and light transmitting layers are continuously adhered over at least two areas of the read only area and the recording and reproducing area, reflectivity of the recording layer is more than 5%, and a push-pull signal output T3 reproduced from the read only area and another push-pull signal output T4 reproduced from the recording and reproducing area before recording satisfies relations of T3?0.1, T4?0.1 and 1.5?T3/T4?0.5.

Abstract: A position information signal pattern is recorded into a recording medium. The position information signal pattern is configured by arranging graphics having a circular shape, a rectangular shape or the like surrounded by a certain closed curve as pattern elements on a plane, and arranging the pattern elements in circumferential and radial directions of a disc so that a phase and a head position establish a proportional relationship in two or more frequency components of a reproduced signal. Position signals of the two frequency components included in the reproduced signal from the position information signal pattern are obtained, and the two position signals are added up with a certain ratio so that a position signal without error is obtained.

Abstract: The present invention provides an information storage apparatus that generates a tracking error signal based on a detection signal, and performs various control operations based on the tracking error signal. When the operation mode is a seek operation mode, the information storage apparatus generates a tracking error signal by holding the peak value of the detection signal. When the operation mode is a tracking operation mode, the information storage apparatus generates a tracking error signal directly from the detection signal. With this information storage apparatus, stable control operations can be performed, regardless of changes of conditions.

Abstract: A magnetic tape has a guide track for optically obtaining a tracking signal and an independent information track for storing information. The magnetic tape is partitioned into different kinds of zones. The guide tracks are provided with grooves or pits serving as tracking marks, and the tracking marks are selectively located in the zones depending on the kind of zone. Thus, the track spacing of the guide tracks in each zone can be increased, so that a tracking control can be performed for a high density recording medium without reducing the spot size of the light.

Abstract: In an optical recording apparatus having an optical pickup, a rotating section is provided for rotating an optical disk which is formed thereon with a guide groove to define a spiral track having a plurality of rounds. The optical pickup has a light source for generating an optical beam and a diffractive grating for diffracting the optical beam to form a main beam and a pair of sub beams opposite with each other relative to the main beam. The optical pickup is operable for irradiating the main beam to the spiral track with accompanying the pair of the sub beams along apposite sides of the spiral track. A servo section operates the optical pickup to enable the main beam to trace the spiral track based on a tracking error signal derived from return lights of the sub beams reflected back from the optical disk. A recording section modulates the main beam for recording of information onto the spiral track while the optical dick is rotated.

Abstract: A system and method for dynamically re-calibrating an optical disc drive during operation is provided. The optical media includes a pitted premastered area that cannot be overwritten and a grooved user-writeable area that can be overwritten. The system can attempt several increasing levels of effort to recalibrate the disc drive until the disc drive reaches a desired level of performance, or the recalibration effort levels are exhausted. During each level of recalibration effort, various calibration values are determined for the optical media and the servo actuator, along with a notch frequency for a notch filter; a focus actuator offset; a tracking actuator offset; a focus control loop gain; and a tracking control loop gain. The optical media disc is divided into zones, and zone calibration tables for each of the zones are generated. Each zone is recalibrated using the corresponding zone calibration table.

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: A digital servo system of an optical disk drive with a calibrated inverse non-linearity function is disclosed. A look-up table is determined, for example, with a focus error signal gain corresponding with a focus error signal offset so that the response of the focus servo system is substantially linear. Additionally, the look-up table can include tracking error signal gain, tracking error signal offset, or tracking loop gain parameters corresponding with the focus error signal offset.

Abstract: An information recording medium in which bottoms of a guide groove and a pit array formed on a disc substrate are allocated on a same flat plane and shaped in flat. Further, in a transition area from a pit array to a guide groove or from a guide groove to a pit array, the information recording medium is provided with an intermediate area composed of a pit array of which height changes from a height between a bottom and a side of a groove to another height between the bottom and a side of the pit array.

Abstract: In an optical disc drive capable of recording and playing back different kinds of optical discs, an actuator driving means brings an objective lens close to the optical disc, focus error signals are generated in front of and behind a position where leaser beam comes into focus on a signal surface of the optical disc, optical disc discriminating means discriminates a thickness of the optical disc from a difference in waveform of the focus error signal which is generated by focus deviation between leaser beam which passes through an outer periphery of the objective lens and leaser beam which passes through an inner periphery of the objective lens, and discriminates a kind of the optical disc from the thickness of the optical disc.

Abstract: In a first mode, an R/W channel starts to monitor read information to thereby detect a servo mark contained in servo information, each time a servo controller generates a servo gate pulse. Upon detecting the servo mark, the R/W channel detects, from the read information, position information contained in the servo information and following the servo mark, at a timing determined by the detection timing of the servo mark. When the first mode has been switched to a second mode, the R/W channel detects the servo mark and position information using the synchronous method.

Abstract: Disclosed is an optical recording disk which records information using lands and grooves and has a shallow & deep groove structure in which groove is different in depth from the other groove adjacent thereto. In the optical recording disk, a playback signal is stabilized by setting the level ratio of an AC component of a sum signal to a DC component of the sum signal in a plurality of spots to be equal to or smaller than a predetermined value.

Abstract: An optical disc apparatus according to the present invention is usable for an optical disc including a bar code area and a control data area adjacent to the bar code area in a radial direction of the optical disc. The optical disc apparatus includes an optical head for directing an optical beam toward the optical disc so as to form an optical spot on the optical disc and output a signal in accordance with the optical beam reflected by the optical disc, a bar code area determination section for determining whether or not the optical spot is positioned on the bar code area of the optical disc based on the signal output by the optical head; and a control section for controlling the optical head so that the optical spot moves toward the control data area, when the optical spot is determined to be positioned on the bar code area.

Abstract: A recording medium that is adapted to maximize the recording capacity and to simplify the configuration of an information recording/reproducing apparatus including a pickup. In the medium, a different type of wobbling signals are preformatted in each of the adjacent land and groove signal tracks. A same-phase wobbling signal provided by wobbling each side of the respective land and groove signal tracks in the same phase and a different-phase wobbling signal provided by wobbling each side of the respective land and groove signal tracks in a different phase are used as the different type of wobbling signals. The physical positions of all the land and groove signal tracks are indicated by the same-phase wobbling signal.

Abstract: A method and apparatus for detecting a topographic feature on a media is described. More particularly, a light scatter detector is coupled to an atomic force microscope. The detector is used detect scattered optical energy reflected from the surface of the media to identify the topographic feature. The atomic force microscope may then be positioned in response to the topographic feature identified.

Abstract: There are provided an information write device and an information read device enabling to generate highly accurate contrast signals. When a main light spot Pc is located at the center of the a groove G, the light spot Pc and sub light spots Psa, Psb are each adapted to radiate a disc DSC such that the sub light spots Psa, Psb radiate positions displaced from the center of the land L. The reflected beams of light from the disc DSC caused by the radiation with the light spots Pc, Psa, Psb are detected to generate push-pull signals each corresponding to the light spots Pc, Psa, Psb, respectively, in accordance with each of the detected signals. Furthermore, a signal to be obtained by amplifying an addition signal, given by adding the push-pull signals each corresponding to the sub light spots Psa, Psb, with a predetermined amplification factor K/n, and a push-pull signal corresponding to the main light spot Pc are added to thereby generate a contrast signal.

Abstract: A wobble detection circuit detects a signal by a common photodetector (light receiving) element from several kinds of media having different pre-formats. Further, the wobble detection circuit changes a gain for amplifying the signal in a wobble signal detection process depending on the pre-format of a reproducing or recording medium to obtain a wobble signal.

Abstract: An optical storage medium includes a plurality of tracks and a plurality of information pits arranged in the tracks. The information pits are designed to produce reflection light upon irradiation of light. The information pits are disposed in a matrix layout so that the reflection light includes at least four diffracted rays. An information pit is offset from the predetermined reference point in the track direction and the tracking direction. Thus, the particular information pit carries information indicated by the offset position relative to the reference point.

Abstract: A method and system for correcting tracking errors in an optical storage medium having multiple tracks arranged in different layers of the optical storage medium, directs a reading spot that is nominally focused on to a track in the optical storage medium, and continually moves the reading spot in axial and radial directions so as to receive a signal having an amplitude which varies according to respective offsets from the track in radial and axial directions. The received signal is used to determine a direction of a respective offset from the track in radial and axial directions, and a location of the reading spot is adjusted accordingly.

Abstract: The present invention relates to loop gain adjustment of a focus/tracking servo in an optical disk apparatus, and provides an optical disk apparatus which can make the loop gain adjustment converge normally even in an optical disk in which prerecorded areas and recorded areas are mixed, and further which always has a stable servo system even when a gain is significantly varied due to changes in the disk state. When an inserted optical disk is determined to be a recordable optical disk by an optical disk type determination means 22, an optical pickup 1 is made seek a previously set area, thereby performing the loop gain adjustment. Further, when a gain is varied during the operation, a gain adjusting means 10 changes over a gain adjustment value.

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 synchronise 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: A disc drive apparatus for recording or playing back data onto and from an optical-disc recording medium having a plurality of signal surface areas outputting detected information as reflected detection signals with different amplitudes, the disc drive apparatus including: reflected-light quantity detection means for detecting a total quantity of a light reflected by a signal surface of the optical-disc recording medium and outputting a reflected-light quantity detection signal representing the total quantity; integration means for integrating the reflected-light quantity detection signal and providing an integration output representing a result of integration of the reflected-light quantity detection signal; and identification-signal generation means for comparing the level of the reflected-light quantity detection signal with the level of the integration output used as a threshold value and for outputting an identification signal identifying a specific signal surface area among the signal surface areas as a

Abstract: A servo mark detector detects a servo mark from each servo information item detected by the servo detector. A counter measures a time period each time a servo mark is detected, thereby measuring a servo interval. A correction circuit corrects a time period T2 on the basis of the measured servo interval and an ideal servo interval. A determination circuit determines which one of the time period T2 and a time period T2? obtained by correcting the time period T2 should be used. A servo-sector-pulse-generating unit generates a servo sector pulse a time period T1 after the detection of each servo mark, and generates a pseudo servo sector pulse when the time period determined by the determination circuit has elapsed after the detection of each servo mark, if the next servo mark is not detected during the determined time period.

Abstract: With the detection of a difference between both sides of a divided focus light spot of the returned light from an optical disk, the measurements obtained by means of said detection is represented as a graph having a more particular point or a sharper point than the light intensity distribution graph of the focus light spot of the returned light from the optical disk.

Abstract: An optical disc drive according to the present invention may be loaded with an arbitrarily selected one of optical discs of multiple types including a first optical disc with grooves and a second optical disc with no grooves.

Abstract: An optical disc drive according to the present invention can read and write data from/on an optical disc 100 including record tracks to write data thereon and guide tracks for guiding a light beam 40. The drive includes: an optical pickup 101 with a converging optical system to focus the light beam 40 and form a spot thereof on the optical disc 100 for reading or writing the data; a tracking control section for controlling the converging optical system of the optical pickup 101 such that the light beam spot 40 follows a selected track on the optical disc 100 rotating; and a control unit 35 for operating the tracking control section in a first mode or in a second mode. In the first mode, the tracking control section makes the light beam spot 40 follow the recording tracks. In the second mode, the tracking control section makes the light beam spot 40 follow the guide tracks.

Abstract: In a method and system for forming light beams onto a disc for a plurality of disc formats, a main beam is directed onto the disc. A side beam is directed onto the disc with a displacement from the main beam, with the displacement being a LCM (least common multiple) distance of respective track pitches for the plurality of disc formats. A tracking servo uses such main and side beams with stable operation for the plurality of disc formats.

Abstract: The invention relates to a disc discriminating method and an optical disc information reproducing apparatus wherein DVD-RAM which is DVD-RAM1 or DVD-RAM2 and DVDRW which is DVD−RW or DVD+RW which cannot be respectively determined based upon distance from the surface of a disc to the recording face, the number of recording faces and the reflectance can be discriminated. In case an optical disc is DVD-RAM or DVDRW, the amplitude of a push-pull tracking error signal is measured by a microcomputer in a state in which servo control is executed based upon a focus error signal. Determination is performed based upon the amplitude of the push-pull tracking error signal, when the amplitude of the push-pull tracking error signal is larger than a predetermined value, the optical disc is judged as DVD-RAM and when the amplitude is smaller than the predetermined value, the optical disc is judged as DVDRW.

Abstract: A land/groove track discriminating method and apparatus for an optical recording medium having a land/groove structure which can stably discriminate the kind of a track even in an unstable state of the system. The kind of the track is discriminated by using the differential characteristic of a tracking error signal in a header region, by using the relation that the phase of a wobbling signal in the lang track is opposite to the phase of the wobbling signal in the groove track, or by comparing phase levels of delayed first and second header region signals. Accordingly, the servo control suitable to the kind of the track can be performed at a proper time, and thus an accurate tracking control can be performed with respect to an optical disc having the land/groove track structure.

Abstract: A control device includes an a focus controller for performing a focus servo control and a focus jump control; an aberration corrector; a command generator for commanding the change of a recording/reading layer from one recording layer to the other layer; a portion for changing an aberration correction value to a value suited for the other recording layer; and a timing adjuster for adjusting an execution timing of the focus jump and a rate of change in the gain of the amplifier in such a manner that a timing when the gain of the amplifier reaches the predetermined gain is within the execution time period of the focus jump.

Abstract: A position control method is disclosed that is capable of precisely and stably controlling a position of an object lens relative to a recording medium. When controlling the position of the object lens in the tracking direction, first, an attempt is made to read address information recorded on the recording medium, and if the address information is not readable, the polarity of the tracking error signal used for servo control is reversed. As a result, even for a recording medium of a low quality or a nonstandard recording medium, which are treated as invalid media in the related art, it is possible to locate the object lens to the target position.

Abstract: A focus-detecting emitter for a data storage device is provided, such focus-detecting emitter including a first emission zone configured to selectively produce a first electron beam portion, and a second emission zone configured to selectively produce a second electron beam portion. The first electron beam portion generates a first spot on a storage medium and the second electron beam portion generates a second spot on the storage medium such that a position of at least one of the first spot and the second spot is indicative of a focus state of at least one of the first electron beam portion and the second electron beam portion.

Abstract: A magnetic tape has a guide track for optically obtaining a tracking signal and an independent information track for storing information. The magnetic tape is partitioned into different kinds of zones. The guide tracks are provided with grooves or pits serving as tracking marks, and the tracking marks are selectively located in the zones depending on the kind of zone. Thus, the track spacing of the guide tracks in each zone can be increased, so that a tracking control can be performed for a high density recording medium without reducing the spot size of the light.

Abstract: The present invention provides a focus position adjustment method for adjusting a focus position by which an optical storage device reads an optical storage medium. The optical storage medium comprises a header and a recording area. The optical storage device generates a focus error signal as reading the medium and utilizes the focus error signal to control the focus of the optical pickup head. After the optical storage device finishes tracking closed loop, the method is performed according to the deviation value between the levels of focus error signals of the header and the recording area to adjust the focus position to make the deviation value fall in a predetermined range. The system comprises a deviation value detection module for determining the deviation value and a focus control module for adjusting the focus position.

Abstract: On an optical disc including a substrate on which pits having at least two different depths are formed, main information is recorded by the shape of the pits and additional information is recorded by the depth of the pit. It is possible to reverse polarity of a tangential push-pull signal dependent on the depth of the pit, and therefore it becomes possible to record information utilizing the depth of the pit. This improves recording density of the optical disc. Further, when information of the optical disc is to be copied, the information recorded by the depth of the pit cannot be copied. Therefore, unauthorized reproduction can be prevented.

Abstract: An optical disk drive capable of securing reliable reproduction of a wobble signal even under a constant angular velocity control of a recordable or rewritable optical disk is disclosed. The optical disk has a guide track wobbled to produce a constant frequency when the optical disk is driven under a constant linear velocity control. An optical pickup unit detects the light reflected from the optical disk, and a wobble signal reproducing section takes out a wobble signal. The wobble signal reproducing section has two band-pass filters; a first band-pass filter detects a center frequency of the wobble signal, which is caused to vary under the constant angular velocity control, and a second band-pass filter has a center frequency set to the detected center frequency whereby the wobble signal is extracted by the second band-pass filter. The extracted wobble signal is subsequently demodulated address information.

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: Audio data of 20 bits is separated into first data of upper 16 bits and second data of lower 4 bits. EFM modulation data is formed from the first data. A laser beam is on/off controlled in correspondence to the logic level of channel data obtained by NRZI modulating a serial data train. The first data, therefore, is recorded in a manner similar to the case of a compact disc. Each pit is controlled so as to have a displacement in the right/left direction for the track center in accordance with the second data and the deviated pit is formed. When data is recorded by the displacement of the pit, since a high frequency component of a tracking error signal changes upon reproduction, the second data can be extracted from the tracking error signal.

Abstract: An optical recording medium that permits high density recording and only needs a recording machine of simple structure, and a machine for reproducing recorded information from such optical recording medium. A track pitch of recording tracks is smaller than a diameter of a beam spot of a scanning laser beam, and tracking pits for tracking control are formed on the respective recording tracks. A certain number of neighboring recording tracks define a group, and in each group the tracking pits are spaced from each other in a recording track direction by a predetermined interval which is smaller than the diameter of the beam spot.

Abstract: A method for multi-track optical data recording comprising the steps of providing an optical recording medium that includes a plurality of parallel, preformatted guide tracks, with sufficient space between adjacent guide tracks for recording a plurality of data tracks; providing relative motion between the optical recording medium and an optical head in a direction generally parallel to the guide tracks; imaging a guide track onto a detector array disposed relative to the optical recording medium; and generating a first tracking error signal representing the cross-track displacement of the guide track relative to the optical head. The method further comprises driving a closed-loop servo system to reduce the residual tracking runout of the guide track and simultaneously recording a band of data tracks in the unpreformatted space adjacent to the guide track and one or more control tracks parallel to the data tracks.

Abstract: When a setup is performed by reproducing conditions corresponding to the first kind of optical disk and a setup is subsequently performed by reproducing conditions corresponding to the second kind of optical disk, the reproducing conditions which succeed to at least a part of the reproducing conditions corresponding to the first kind of optical disk are used as reproducing conditions corresponding to the second kind of optical disk and the setup is performed. When the setup is completed, the reproducing conditions corresponding to the optical disk as a target of the setup are stored. When the same optical disk is set up again, the stored reproducing conditions are used.