Abstract: The invention provides an apparatus for controlling servo signal gains of an optical disc drive. The apparatus adjusts the gains of a plurality of servo signals controlling a servo system of the optical disc drive according to a closed-loop mode or a state-reloading mode whenever the optical disk drive encounters an operating state transition. In closed-loop mode, at least one AGC loop of the apparatus compensates the gains of the servo signals with a selectable bandwidth during a specific period after the operating state transition to accelerate the convergence of the servo signals. In state-reloading mode, at least one AGC loop of the apparatus reloads the previously saved convergence values or pre-determined values as the initial values according to the current operating state immediately after the operating state transition to accelerate the convergence of the servo signals.

Abstract: An optical disk apparatus according to the present invention is an optical disk apparatus for performing at least one of: recording data to a plurality of types of optical disks including a recordable optical disk and a read-only optical disk which are produced according to the BD specifications; and reproducing data from the optical disks. This apparatus includes: a means (506, 507) for irradiating a management area 502 of an optical disk 501 with a light beam while not performing tracking control, and generating a track position signal (push-pull TE or phase difference TE) from light which is reflected by the management area 502; and a disk determination means for determining, based on the track position signal obtained from the management area 502, whether the optical disk 501 mounted in the optical disk apparatus is a recordable optical disk or a read-only optical disk.

Abstract: A system for determining groove/land (G/L) switching points of an optical disc is disclosed. The system includes a motor rotating signal generating apparatus, an detection apparatus, and a G/L switching point generating apparatus. The motor rotating signal generating apparatus is for sensing the rotation of a motor to generate a motor rotating signal with a period corresponding to the rotation of the optical disc. Also, the detection apparatus is used for receiving the motor rotating signal and an original G/L switching point signal and utilizing the motor rotating signal and the original G/L switching point signal to determine a location of an reproduced G/L switching point of the optical disc. The G/L switching point generating apparatus is for generating an reproduced G/L switching point signal according to the location of the reproduced G/L switching point determined by the detection apparatus.

Abstract: An optical disk is equipped with a predetermined mark. A frequency generator outputs an FG pulse of frequency corresponding to the rotational speed of a spindle motor used for rotationally driving the optical disk. The edge of the FG pulse detected by an edge detection section is counted by an FG counter. An angle counter measures the duration of a time from appearance of an edge of the FG pulse until a point in time when the mark affixed to the optical disk 1 is detected. A count value of the FG counter, which has been acquired at the point in time when the mark is detected, and a count value of the angle counter are saved. In a case where a visible image is rendered, encoding of a visible image to be rendered is started when the count value of the FG counter and the count value of the angle counter have become equal to the respective saved values.

Abstract: A focus servo apparatus for an optical disc apparatus including an objective lens to converge laser beam on an information recording surface of an optical disc, and an actuator to move the objective lens in a focusing direction crossing the information recording surface, the focus servo apparatus comprising: a retaining unit configured to retain control data for driving the actuator; and a setting unit configured to set the control data retained by the retaining unit as initial data for driving the actuator, in the case of driving the actuator, to detect a position of the objective lens where the laser beam is focused on the information recording surface, as a target position when performing focus servo.

Abstract: An objective lens is moved with a disc irradiated with laser light. A maximum value FEmax and a minimum value FEmin of the focus error signal, and a maximum value FSmax of the amplitude of a focus sum signal are measured. “(FEmax?FEmin)/FSmax” is compared with a determination value to determine the type of a disc.

Abstract: A recording and reproducing method for recording and/or reproducing information from a record carrier that comprises a plurality of recording layers layered in its film thickness direction and a guide layer having a plurality of tracks carrying tracking servo information, wherein a record mark is formed on each recording layer of the record carrier. The method comprises: a focusing step of converging a servo light beam onto the guide layer as well as selectively converging a main light beam group onto one of the recording layers through a common objective lens, wherein the main light beam group comprises a plurality of main light beams neighboring each other; a tracking step of performing a positioning control of the objective lens so that the servo light beam is tracking on one of the tracks; and a recording and/or reproducing step of performing recording and/or reproducing information with the main light beam group while performing the focusing step and the tracking step.

Abstract: It is an optical disk apparatus that comprises: a laser drive device for outputting a test power larger than a prescribed value in a gap section; an optical pickup for forming a beam spot on a disk and detecting reflected light; a focus error detector for detecting position shift between a recording face of the information recording medium and the beam spot; a focus control device for controlling the position shift; and a focus drive device for driving an objective lens in directions far from and close to the disk, wherein, in the gap section, the focus drive device keeps a focus drive output level of right before the laser drive device outputs the test power, and sets a recording power such that the emitted light power becomes the prescribed value.

Abstract: A system and method for calibrating a recording track offset of an optical storage device accessing an optical storage medium of land/groove type. The system includes: a tracking servo loop arranged to control tracking operations of an optical head of the optical storage device; a track offset control loop arranged to control the recording track offset for the tracking servo loop; a controller arranged to enable a latest value of the recording track offset to be a readout value for utilization in a recording process performed later; and a comparator arranged to compare a recording length with a threshold value and generate a flag to represent whether the recording length is a long recording length, wherein the latest value is derived from the track offset control loop.

Abstract: A high-density read-only optical disc, and an optical disc apparatus and method using the same. The apparatus and method record data on a lead-in area of a high-density read-only optical disc such as a BD-ROM (Blu-ray disc ROM (Read Only Memory)) in the form of pre-pit strings associated with an HFM (High-Frequency Modulated) groove applied to a BD-RW (Blu-ray Disc Rewritable). Moreover, the apparatus and method continuously apply the same tracking servo operation to an entire area of the same high-density read-only optical disc or rewritable optical disc. Therefore, the apparatus and method can simplify an algorithm for controlling a plurality of tracking servo operations, and avoid an increased size of the optical disc apparatus.

Abstract: An apparatus for reading subdivided information from an optical disk, which comprises a track groove and on which information is recorded along the track groove is disclosed. The apparatus includes an optical head, which irradiates the optical disk with light and generates an electric signal responsive to part of the light that has been reflected from the optical disk, read signal processing means for generating a wobble signal which has an amplitude changing with the wobble pattern from the electric signal, rise value acquiring means for sampling and holding an absolute gradient value of the wobble signal when the signal rises, fall value acquiring means for sampling and holding an absolute gradient value of the wobble signal when the signal falls, and subdivided information detecting means for determining the subdivided information by majority by comparing the values held by the rise and fall value acquiring means with each other.

Abstract: Provided is a recording and retrieval apparatus for a multi-layer optical disk. A multi-layer optical disk in which a plurality of recording layers and a single servo layer are combined to form a set is used. A spot for the servo layer and a spot for the recording layers are turned on in a time-sharing manner. Servo signal detection areas are formed discretely in the servo layer. The servo signal detection areas and data recording areas are provided so as not to overlap each other when viewed from the spot incident side. Thus, separation of data from each of the layers can be done by even a single photodetector without interference.

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: An optical disc drive apparatus has: a rotation angle counter cleared when the number of pulses in a frequency multiplied FG signal has reached a value corresponding to one rotation of the disc; a switching sector detector detecting polarity switching locations based on the output signal of an RF processor to clear the rotation angle counter; a switching window signal generator generating a switching window signal having a predetermined width based on the count value; a timing signal generator generating a timing signal for each sector based on the output signal of the RF processor; and a polarity switching signal generator generating a polarity switching signal based on the switching window signal and the timing signal.

Abstract: In an optical recording medium of a single-sided incident type having a plurality of recording layers, recording/reading conditions (for example, tracking polarity, recording pulse strategy, recording recommended power, etc.) can be instantaneously switched according to each of the recording layer, and recording or reading of information can be accurately and surely performed under recording/reading conditions adapted to each recording layer. A control unit reads out layer information from one recording layer of the optical recording medium in which the layer information is recorded in each of the plural layers, on which recording or reading of information can be performed by irradiating a laser beam from one side thereof (layer information reading step), and controls so that recording or reading is performed under recording/reading conditions adapted to a recording layer specified on the basis of the layer information (recording controlling step).

Abstract: A high-density read-only optical disc, and an optical disc apparatus and method using the same. The apparatus and method record data on a lead-in area of a high-density read-only optical disc such as a BD-ROM (Blu-ray disc ROM (Read Only Memory)) in the form of pre-pit strings associated with an HFM (High-Frequency Modulated) groove applied to a BD-RW (Blu-ray Disc Rewritable). Moreover, the apparatus and method continuously apply the same tracking servo operation to an entire area of the same high-density read-only optical disc or rewritable optical disc. Therefore, the apparatus and method can simplify an algorithm for controlling a plurality of tracking servo operations, and avoid an increased size of the optical disc apparatus.

Abstract: An optical disc medium (10) is provided with a data recording area (12) having the spiral recording track (11) and a lead-in area (13) composed of an embossed pit. In the lead-in area (13), information indicating a characteristic range of a signal detected by an optical head from a groove track is previously recorded. In accordance with a kind of the optical disc medium (10), even when the characteristic range of the signal detected by the optical head from the groove track is different, since the information indicating the characteristic range is previously recorded on the optical recording medium (10), tracking operation of the recording track can be performed under conditions within the characteristic range. Therefore, the tracking operation of the recording track (11) can be accurately performed to any kind of optical disc medium (10).

Abstract: An optical disk device includes a pickup head, and a controller which controls the pickup head. The controller subtracting a second measured value determined from an amplitude value of the tracking error signal when the pickup head irradiates a second area of the optical disk with a first DVD laser beam, from a first measured value determined from the amplitude value of the tracking error signal output when the pickup irradiates a first area of the optical disk with the first DVD laser beam, to determine an evaluation value. The controller determining that the optical disk is the first DVD if the evaluation value is smaller than a reference value, and determining that the installed optical disk is a second DVD if the evaluation value is larger than the reference value, the second DVD optical disk having a smaller track width than the first DVD optical disk.

Abstract: An optical-information recording medium includes a substrate that includes a servo surface having a servo pattern thereon; an information recording layer laminated on the servo surface of the substrate capable of recording information as a hologram produced by interference between an information beam containing the information and a reference beam; an address servo area that is formed as a part of the servo pattern, and that records therein address information and clock information for aligning a beam, emitted from an optical-information recording apparatus for recording information in the information recording layer, to a target position in the information recording layer; and a following up servo area that is formed as a part of the servo pattern, and that is to be irradiated by the beam to make the beam follow a rotation of the optical-information recording medium.

Abstract: A focus servo apparatus which comprises an optical pickup having a power lens that changes an incidence angle of laser light incident on an objective lens and a power lens actuator that drives the power lens along an optical axis direction. In a focus search operation, the focus servo apparatus controls the power lens actuator to drive the power lens along the optical axis direction and detects having been brought into the focus servo area on the basis of a focus error signal obtained from photo-reception outputs from a photo-detector of the optical pickup, and then allows a focus servo to be in lock and returns the power lens to its initial position with driving the objective lens so as to maintain the lock state.

Abstract: An optical disk apparatus includes: a servo control unit, operable to execute a servo control of focusing based on a focus error signal and to execute a servo control of tracking based on a tracking error signal; a detrack regulating unit, operable to execute a detrack regulation for setting an offset voltage, which is to be added to the tracking error signal, to be a voltage for giving the highest signal quality of an output of an optical pickup; and a defocus regulating unit, operable to execute a defocus regulation for setting an offset voltage, which is to be added to the focus error signal, to be a voltage for giving the highest signal quality of the output of the optical pickup. The defocus regulation is executed in a state in which the servo control of the focusing and the servo control of the tracking are executed. The defocus regulation is executed after the detrack regulation is executed, in the state in which the servo control of the focusing and the servo control of the tracking are executed.

Abstract: In one aspect of the invention, a computer system comprises application logic executable to search an optical medium for at least one type of file system that may be resident on the optical medium. In response to identifying the presence of at least one type of file system resident on the optical medium, the system readies a media driver of an apparatus to make the at least one file system available for access.

Abstract: An optical disk device is disclosed that includes loop gain adjustment means for finding the first tracking loop gain of a first region, and loop gain estimation means for estimating the second loop gain of a second region on the basis of the loop gain of the first region. Accordingly, it is possible to set the optimal tracking control loop gain for all regions. As a side benefit, good tracking control stability can be ensured regardless of the region, which improves the reliability of reproduction and recording.

Abstract: A tilt correcting apparatus makes a tilt correction in an information recording apparatus or the like capable of recording record information onto an information recording medium, on an information recording surface of which a track having a wobble is formed, by emitting laser light thereonto. The tilt correcting apparatus is provided with: a correcting device for changing an irradiation angle of the laser light; a controlling device for controlling the correcting device such that the irradiation angle is set to be each of a plurality of predetermined angles before the record information is recorded; a wobble detecting device for detecting a wobble signal corresponding to the wobble from a photo-detection signal of light from the track caused by the laser light; and a tilt determining device for determining an amount of tilt of the information recording surface, on the basis of the detected wobble 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: An optical information reproducing method capable of determining multi-level information with high precision, and an apparatus for the method. Specifically, a cell having a reduced multi-level is provided in a portion of a data region to perform the level correction or automatic gain control. For example, a cell recorded with an M-value for each group including a plurality of cells, each of which is recorded with an N-value (N>3, M<N), is provided. A reproduction signal level of a cell recorded with the N-value, which follows the cell recorded with the M-value, is corrected based on a difference between a cell center value of a reproduction signal sampled when a center of a light spot is moved to a center of the cell recorded with the M-value and a reference value obtained from learning information.

Abstract: An optical head includes a plurality of light receiving areas, which receive a first type of reflected rays where zero-order and first-order components of the light diffracted by a track are superposed one upon the other to generate a light quantity signal representing the quantity of light of the first type of reflected rays, and a non-light-receiving area, which is provided between the light receiving areas so as not to receive a second type of reflected ray consisting essentially of the zero-order components. As measured in a first direction in which the light receiving areas are arranged, a gap between the light receiving areas is longer than the width of the non-light-receiving area. The optical head further includes a tracking error signal generating section for generating a tracking error signal based on the light quantity signal.

Abstract: An optical disc apparatus includes an emitter which emits a laser beam to a optical disc, a divided photodetector including a first divided portion and a second divided portion disposed in a light path of the reflected beam from the optical disc, and producing a first photodetector signal and a second photodetector signal, a phase difference detector which produces a phase difference signal from a phase difference between the first and the second photodetector signals, an integrator which produces a integral signal from a integration of the phase difference signal, a tracking controller configure to perform tracking control based on the integral signal, and a limiter which limits a signal to be supplied from the divided photodetector to the phase difference detector or a signal to be supplied from the phase difference detector to the integrator based on a detection status of a signal detected by the divided photodetector.

Abstract: A method for recording and reproducing information to/from with an optical recording medium, with which either in-groove recording or on-groove recording is selected according to a type of the recording medium, and information can be recorded and reproduced with good signal quality. In this method a laser beam is reflected by an information recording layer and is received by a photodetector that has been split into at least two parts by a split line parallel to the direction of the grooves. Further, the laser beam is reflected in a region in which a groove width is greater than a width between grooves, and the method determines whether the grooves on a side where the laser beam is incident are convex or concave based on a sum signal and a difference signal of photodetection signals outputted from the photodetector.

Abstract: In the first and second light-receiving regions equally divided into two in parallel with the track of the optical disc, the reflected light received from the optical disk is converted into electric signals and fed out by individual light-receiving regions. Then, the light-receiving ratio indicating the ratio of amounts of received light is calculated from the amplitude of the electric signal generated in the first light-receiving region and the amplitude of the electric signal generated in the second light-receiving region. Then, it is determined whether or not an absolute value of the light-receiving ratio is larger than a predetermined vale. When the absolute value is larger, the movement of the objective lens in a radial direction is corrected by incorporating a predetermined correction value.

Abstract: An optical pickup includes a detector, a plurality of light guiding units, and a switching controller. The detector detects, using a plurality of detection areas, a reflected light beam that is emitted from a predetermined light source and is reflected off an optical recording medium. Each of the light guiding units has a specific light guide pattern and inputs a predetermined part of the reflected light beam to a predetermined detection area in accordance with the light guide pattern. The switching controller switches and selects the light guiding unit that acts on the reflected light beam from among the plurality of light guiding units according to a predetermined switching condition.

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: 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: When recording on a holographic recording medium by using a recording beam, the time required for an asking servo control to recover is reduced to increase the data transfer rate. In the holographic recording apparatus 10, a laser beam from a laser light source 16 is formed into a collimated beam having an expanded beam diameter and then is divided into an object beam and a reference beam. The divided object beam is modulated according to information to be recorded, and these object and reference beams are made incident on the reflective surface of a rotating polygon mirror 18, while maintaining collimated beam shapes and being adjacent to each other, through a condenser lens 24 having a focal point behind the reflective surface of the polygon mirror 18.

Abstract: A visible pattern is obtained by modulating the digital sum value. Because the digital sum value modulation allows the choice of several different channel bits groups between DC control points, the selection of a group of channel bits resulting in a change of reflection. This creation of a visible pattern is highly suitable for Blueray as the parity preserving property of the channel code guarantees disparity inversion by the DC-control bit, which keeps the DSV excursions between hard limits. As a result only small DSV deliberate variations are required to produce a visual watermark, which will not deteriorate the bit-detection margin of the optical disc.

Abstract: An optical disk drive is designed to read and/or write data from/on a spiral string of tracks where land and groove tracks are alternated. The drive includes: a light source for radiating a light beam; a lens for converging the light beam; a mechanism for moving the lens; a photodetector for generating an electrical signal based on at least a part of the light beam reflected from the optical disk; and a control section for controlling the light source and the mechanism responsive to the electrical signal. While performing a seek operation by having the lens moved by the mechanism such that a target track, from/on which the data should start being read or written, is irradiated with the light beam, the control section tries to get a PLL locked by irradiating another track, which precedes the target track by at least one, with the light beam.

Abstract: A high-density read-only optical disc, and an optical disc apparatus and method using the same. The apparatus and method record data on a lead-in area of a high-density read-only optical disc such as a BD-ROM (Blu-ray disc ROM (Read Only Memory)) in the form of pre-pit strings associated with an HFM (High-Frequency Modulated) groove applied to a BD-RW (Blu-ray Disc Rewritable). Moreover, the apparatus and method continuously apply the same tracking servo operation to an entire area of the same high-density read-only optical disc or rewritable optical disc. Therefore, the apparatus and method can simplify an algorithm for controlling a plurality of tracking servo operations, and avoid an increased size of the optical disc apparatus.

Abstract: A method for a focus error signal adjustment in an optical disk device which shapes a focus error signal and enables a high-accuracy focus servo is provided. In a DVD-RAM having an emboss data zone and a rewritable data zone, a focus error signal is generated with the DVD-RAM remaining still in a position where an emboss pit is not formed in the rewritable data zone, and a waveform of the FE signal is shaped so that the waveform is symmetrical with respect to a reference point. Then, the FE signal is generated in the emboss data zone and an amplitude of the FE signal is adjusted. The amplitude of the signal which is obtained by increasing the the amplitude of the FE signal whose amplitude is adjusted by approximately 6 dB is applied to the amplitude of the focus error signal in the rewritable data zone. Consequently, a high-accuracy focus servo based on the FE signal, whose amplitude is adjusted and waveform is shaped, can be achieved without an error caused by the emboss pit.

Abstract: The present invention discloses an apparatus and method for accurately converting a groove/land polarity upon a groove/land track change on an optical medium, by way of initially deciding a reference groove/land changing point or a decoded PID of any one specific sector formed on the optical medium. By counting a specific number of sectors from the reference groove/land changing point or the specific sector, a subsequent groove/land changing point will easily be approached for converting the groove/land polarity, and even the other oncoming track changing points on the optical medium also can be determined.

Abstract: A method for adjusting an aberration is disclosed that adjusts the aberration existing in a light spot by using a control signal generated from a wobbling signal and a reproduction signal, and thereby maintaining an appropriate S/N ratio for both the wobbling signal and the reproduction signal even when astigmatism, spherical aberration, or other aberrations are present. In an optical pickup, by moving a collimator lens along a light path, a spherical aberration is generated on the light emitted from a light source, a reproduction signal (RF signal) is obtained from the light reflected from an optical disk, a wobbling signal is obtained from the light reflected from grooves on the optical disk, and the correction aberration is adjusted based on the RF signal and the wobbling signal.

Abstract: The determination on the reach to a BCA by using a pull-in signal in a seek for the BCA may eliminate the necessity of a position sensor for determination of the reach to a BCA, for example, which can realize a seek independent of a count of the number of steps by a stepping motor, for example. Thus, the construction can be simplified, and the costs can be reduced. Furthermore, the required accuracy of disk chucking and mechanical accuracy of the mechanisms may be alleviated, which can provide simplicity in design and manufacture. The pickup unit can be allowed to perform the secure reading of information in a BCA by, after the transporting unit is stopped based on the determination on the reach to the BCA, monitoring the determination results (determination signals) based on a pull-in signal, for example, with the objective lens at different positions and controlling the position of the objective lens to an optimum position.

Abstract: Handling writing new data includes creating a journal entry that points to a first storage location containing old data to be replaced by the new data, where the journal entry is maintained after writing the new data, allocating new storage space having a second storage location, and writing the new data to the new storage space at the second storage location. The storage space may be provided by at least one storage device. Allocating new storage space may include remapping a switch coupled to the at least one storage device. The new data may be written by a host coupled to the switch. The switch may present the host with a logical storage area that is created by the switch mapping to different locations of the at least one storage device. The mapping may be transparent to the host. The switch may include at least one processor and a corresponding memory. The journal entry may be part of a journal that is stored in the memory. The storage space may correspond to a disk array storage device.

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 disk drive includes a pickup head, a servo circuit, and a controller. An optical disk has a first area and a second area for which different tracking methods are to be used. The controller may cause the pickup head to make a seek for a target address in the first area from a position in this area that is farther from the boundary between the two areas than the address. If the controller cannot perform tracking servo control after the seek is made, and if the calculated address is located in a critical region, the controller immediately causes the pickup head to make a seek by a specified number of addresses toward the position farther from the boundary. After the seek is made, the controller performs tracking servo control again.

Abstract: A method for identifying a type of an optical disk includes the steps of: turning on a laser diode of an optical pickup and focusing light emitted from the laser diode on the optical disk; moving the optical pickup to obtain a plurality of servo signals; reading a specific servo signal from the servo signals; and determining the type of the optical disk according to the count of enabled times of the specific servo signal and a corresponding enabled time period.

Abstract: A playback apparatus that plays back a recording medium having recording layers includes an optical head irradiating the recording layers with laser light using an objective lens and reading information recorded in the recording layers; an actuator holding the objective lens; focus servo means for driving the actuator to execute focus servo; layer movement driving means for driving the actuator to perform movement of the objective lens in an interlayer direction; tracking servo means for driving the actuator to execute tracking servo; center-point servo means for driving the actuator to execute center-point servo for setting the objective lens to a center point position; and layer jump sequence control means for performing a series of layer jump operations and causing the center-point servo means to execute the center-point servo in a predetermined time within a period during which the series of layer jump operations is performed.

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 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 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: A method, medium, and device changing a play mode if an error occurs in a process of discriminating the type of optical discs. The method includes the operation of discriminating a type of an optical disc loaded in an optical player, and if the optical disc is discriminated as one of a plurality of optical discs that belong to a first type, setting the play mode of the optical player to a play mode corresponding to the type of the discriminated optical disc, reading and playing data recorded in the loaded optical disc, and if the optical player is unable to reproduce the data recorded in the optical disc, then changing the play mode of the optical player to a play mode for reproducing one of a plurality of optical discs that belong to a second type.