Abstract: A speed profile constituting the target speed for the next drive process during searching is generated by target speed generating section 140 and tracking actuator 132 is driven using the error signal in regard to the speed of movement of the light beam calculated by movement speed detection section 141 from a pulse signal obtained by converting the TE signal to binary form. Also linear motor 139 is driven using the difference signal obtained from the target speed and the speed of movement. Tracking actuator 132 is controlled so as to suppress swinging of focusing lens 107 during searching and linear motor 139 moves, during searching, under tracking control to a target speed.

Abstract: An optical-disk play-back system has a lens that receives a light beam reflected from a data surface of an optical disk. The lens focuses the light on four quadrant photodiodes. The position of the lens relative to the photodiodes is adjusted by a standard tracking control loop. In addition, the sledge position is controlled by a sledge-center-error signal. Since the sledge position changes only infrequently, the center error is a low-frequency signal. A non-linear center-error-generating circuit uses two op-amp stages. Signals from an inner pair of photodiodes are summed and applied to one input of the first-stage op amp, while signals from an outer pair of photodiodes are summed and applied to the other input of the first-stage op amp. The first-stage op amp output an overall error signal that includes high-frequency errors. A high-pass filter removes low-frequency components output from the first-stage op amp. The high-pass filter drives an inverting input of the second-stage op amp.

Abstract: An apparatus to generate a seek direction detecting signal for an optical pickup to determine a position of a center of an optical spot focused on an optical disk relative to a center of a track, which focuses a main beam on a first optical detector and a sub-beam having a predetermined aberration in a radial direction on a second optical detector using a light dividing unit. The second optical detector has an inner and an outer pair of light receiving portions arranged along the radial direction, the inner pair being between the outer pair. A signal processing portion includes a first signal processing portion to detect a track error signal from signals output from the first optical detector, and a second signal processing portion to generate the seek direction detecting signal from signals detected by the second optical detector and the track error signal.

Abstract: A recording and/or reproducing apparatus for a disc-shaped recording medium includes an optical head, a disc rotationally driving unit, a transfer unit, and an eccentricity amount measuring unit. The eccentricity amount measuring unit includes a controller and an error signal generator which generates an error signal exhibiting the amount of relative displacement of a light beam irradiated from the optical head onto the disc-shaped recording medium with respect to a track on such medium. The controller detects the peak and trough values of the error signal supplied from the error signal generator and compares a difference signal exhibiting a difference between the detected peak and trough values and a reference value to calculate the amount of eccentricity of the disc-shaped recording medium based on a comparison output signal.

Abstract: A seek control unit divides a seek control section into four segments, i.e., an acceleration segment, a maximum constant-velocity segment, a deceleration segment and a minimum constant-velocity segment. During the migration from the acceleration segment to the deceleration segment, the seek control unit newly provides a maximum constant-velocity control segment in which the maximum velocity Vd after acceleration remains unvaried. A time tuning unit adjusts and sets a period of time TC2 of the maximum constant-velocity control segment so as to minimize at all times a period of time TC1 of the minimum constant-velocity control segment based on the minimum velocity VC after termination of the deceleration control with respect to variances of the seek distance to the target track.

Abstract: In an optical information reproduction device for reproducing information from an optical disk medium on which an identification information area including first identification information shifted radially outward with respect to the center of a recording track by a specified distance and second identification information shifted radially inward with respect to the center of a recording track by a specified distance, and a user information area disposed along the center of a recording track are disposed, information is reproduced using a sum signal and a difference signal of the outputs from a split photodetector having at least two light-receiving parts disposed on opposite sides of a track tangential line. The first or second identification information signal is inverted and the direct-current component in the identification information signal and the user information signal are removed.

Abstract: A difference counter in a servo system includes RX signal processing circuitry, TX signal processing circuitry, and a latch. The RX processing circuitry includes a RX z-hold (zero order) circuit, a RX delay circuit coupled thereto, and a RX XOR logic circuit coupled thereto for producing an RX processed signal. The TX processing circuitry includes a TX z-hold circuit, a TX delay circuit coupled thereto, and a TX XOR logic circuit coupled thereto for producing an TX processed signal. The RX and TX processed signals are fed into the latch which, in response, generates a noise-free quarter track signal. Half and full track signals are generated therefrom to further process the signal track information.

Abstract: A method for moving an optical head from an initial track to a target track on a storage medium having data arranged in tracks thereon. The method includes determining a track crossing number indicating a number of tracks between the initial track and the target track, moving the optical head from the initial track toward the target track, and measuring a reflectivity level of light from the medium. The method continues with deriving a tracking error signal responsive to the reflectivity level. A waveform of the tracking error signal has zero crossings corresponding to the optical head crossing one of the tracks. The method may further include incrementing a track count number for each the zero crossing, and passing the reflectivity level through a high pass filter to obtain a data indicator signal. In this embodiment, a waveform of the data indicator signal has indicator points corresponding to the zero crossings.

Abstract: An optical pickup position control device according to the present invention automatically adjusts tracking with precision and in a short time. Two deviation signals, which express deviation of a light beam, projected by a pickup which uses the three-beam method, from a target track of a disk, are digitized by two AD converters. Two high-pass filters extract from the deviation signals AC signals, producing a tracking error signal. Further, two low-pass filters extract from the deviation signals DC signals (offset components). Two other low-pass filters extract from the deviation signals low-band signals containing DC components. Using the various foregoing signals, a control circuit calculates correction values to be applied to two offset correcting circuits and to two gain/balance correcting circuits, and corrections are performed collectively and simultaneously on the basis of these correction values.

Abstract: Method for controlling track jump in an optical recording medium for writing/reading data on/from land/groove tracks having depths different from each other in a direction of a beam incident, including the steps of (1) adjusting an offset of a servo error signal generated by using an optical signal reflected at the optical recording medium consistent to the land track, (2) adjusting an offset of a servo error signal generated by using an optical signal reflected at the optical recording medium consistent to the groove track, (3) selecting the servo error signal having the offset adjusted consistent to the land/groove track in the step (1) or (2) in response to a land/groove switching signal, (4) receiving a track jump command, and determining the track jump command of being an ‘N’(‘N’ is an odd numeral) track jump command, and (5) if the track jump command is determined of being an ‘N’(‘N’ is an odd numeral) track jump command in the step (4), after switching th

Abstract: An optical disk has a pattern for detecting an amount of a tilt of a disk. The optical disk has a code train having a pit pattern or a mirror pattern which is recorded on a concentrically or spirally formed track, such that a tilt detection pattern having a predetermined code train is recorded at least in a partial area of the disk. Thus, since a pattern for tilt detection is recorded in a portion of a disk, a tilt of a disk can be detected by a common quadrant photodetector without an additional apparatus such as a photo coupler.

Abstract: A track discrimination signal can be generated without requiring the use of a large number of parts or a complex device configuration even when an optical recording medium adapted to the “land/groove recording system” such as a “DVD-RAM” is used. A main light spot is and auxiliary light spots are formed on an optical disc for signal recording and signal reproduction.

Abstract: An optical disk reproducing apparatus of the present invention includes a body, a disk motor which rotates a disk in which information recording tracks are formed concentrically or spirally on an information recording surface, a base fixed onto the disk motor and elastically suspended with respect to the body, and an optical head which is suspended with an elastic member from the base and is displaceable in a radial direction of the disk.

Abstract: A reproducing apparatus and method are provided in accordance with the invention. The apparatus includes a reader for reading out data from a recording medium, a controller for controlling the position of the reader, and a determiner for determining a number of tracks the controller is to move the reader. The apparatus also includes a comparator, which compares whether the determined number of tracks is less than a predetermined number of tracks in which each of the tracks has an essentially equal number of sectors therein. If so, the controller moves the position of the reader in accordance with the equation Tj=|St−Sc|/Sn wherein Tj is the number of tracks said reading means is to move, St is the address of the target sector to be read out next, Sc is the address of the current sector, and Sn is the essentially equal number of sectors in a track. A method utilizing the apparatus is also provided.

Abstract: A track seeking and track locking method in an optical storage device capable of computing protection intervals such that any state transition of the TEZC signal and the RFZC signal within the computed protection interval is prohibited. The method is also capable of preventing the interference of the TEZC and the RFZC signal due to glitches in the TE signal and the RFRP signal, thus reducing track errors and speed computational errors.

Abstract: A method for performing a seek control operation for a disk device of the type having a pickup for reading/writing data from and to a disk is provided. The method includes the steps of counting mirror signals generated for every revolution of the disk recording medium, where each mirror signal corresponds to one of the tracks radially arranged on the disk recording medium; moving a pickup until the counted number of mirror signals is equal to a predetermined number of tracks required for the pickup to pass to reach a target track. The method further includes the steps of checking respective intervals of successive mirror signals; determining if there is a difference in length between intervals of two successive mirror signals; and executing a correction mode by adding or subtracting a correction value to the counted number of mirror signals if there is a difference in length between intervals of two successive mirror signals.

Abstract: Disclosed is a seek control method in an optical storage device, of seek-moving a light beam of an optical head from a certain track on an optical storage medium to a desired track. This seek control method comprises a step of calculating a target position, a step of detecting a present position from a track error signal indicating a relative position between the light beam and the track, a step of calculating such a feedback control quantity as to zeroize an error between the target position and the present position and a step of controlling a moving mechanism for moving the light beam in accordance with the feedback control quantity.

Abstract: In the optical head transfer circuit of the related art, the sled error signal generated only via a low-pass filter has been used as a tracking error signal. However, the present invention provides a portable type reproducing apparatus which compensates a DC element corresponding to a shifting displacement of an objective lens generated depending on a change of attitude of the reproducing apparatus with a sled feed mechanism, and does not result in deterioration of reproducing characteristics depending on vertical or horizontal installation. The present invention has realized much improvement in vibration characteristics, because a signal from which the DC element is eliminated corresponding to the shifting displacement of the objective lens is used as the tracking error signal and the sled error signal is generated depending on a signal from which the DC element is not yet eliminated.

Abstract: A method for reducing the travel time for an optical pick-up and an apparatus thereof are provided to precisely control the tracking of said optical pick-up. The method comprises the steps of: (i) detecting the number of revolutions of the optical disc to determine the number of track-jumping signals produced in a unit time due to the rotation of the optical disc; and (ii) adding the number of track-jumping signals obtained in step(i) to the number of track-jumping signals detected in a unit time by the pick-up controller in the case that the optical pick-up moves outwardly, and subtracting the number of track-jumping signals obtained in step(i) from the number of track-jumping signals detected in a unit time by the pick-up controller in the case that the optical pick-up moves inwardly.

Abstract: A method for detecting the speed of a sledge motor in an optical storage device. In response to a track jumping command, a tracking servo output signal is expanded onto an orthogonal space to obtain simulation parameters corresponding to the tracking servo output signal. A pseudo-tracking servo output signal is generated according to the simulation parameters of the tracking servo output signal. Then, the pseudo-tracking servo output signal is used to compute the speed of the sledge motor.

Abstract: An optical disc system for efficiently controlling a sled motor is provided.

Abstract: A system and method for generating position error signals within a magneto-optical computer memory device whose track pitch is close to the full width half maximum width of the laser spot, the narrow track being typical of data stored on magnetic super resolution media. The magneto-optical computer memory device comprises a storage media for storing information, position marks embossed on the storage media, a head device coupled to the storage media for sensing the position marks to generate position error signals, and a correction device coupled to the head device to access the position error signals and responsively position the head device to correctly sense the stored information.

Abstract: There is provided an apparatus for compensating for an eccentricity of an optical disc, including a driver on which an optical disc is mounted for rotation, an optical head for emitting optical beams to the optical disc and receiving optical beams reflected from the optical disc, a mover to which the optical head is secured and which moves in a radius-wise direction of the optical disc, a track cross generating circuit which receives a track error signal from the optical disc and transmits a track cross pulse, and a controller which receives the track cross pulse to thereby determine an eccentricity of the optical disc in view of the optical beams reflected from the optical disc, and controls a rotational frequency of the optical disc in accordance with the thus determined eccentricity. The apparatus provides an advantage that an average transfer rate is increased for the long run.

Abstract: A method for reducing the turn-back in response to an actual and a target speed in an optical storage device. The method includes the following steps: (a) determining whether the turn-back of the optical pickup head occurs; if the turn-back occurs, step (b) is executed and if the turn-back does not occur, a speed error is obtained according to the target speed and the actual speed; (b) determining whether the number of turn-back tracks is greater than a default value; if the number of turn-back tracks is not greater than the default value, the speed error is set to zero and if the number of turn-back tracks is greater than the default value, the speed error is obtained according to the target speed and an inversion of the actual speed.

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: When a disc is driven at a low speed, the number of tracks crossed by a beam spot of an optical pickup (3) is determined as the number of crossing tracks corresponding to an amount of mass eccentricity of the disc. If this number of crossing tracks exceeds a first threshold value, the disc is rejected as a non-conforming disc. When the disc is driven at a high speed, the number of tracks crossed by the beam spot is determined, a value remaining by subtracting the number of crossing tracks at the low speed from the number of crossing tracks at the high speed is determined as an amount of vibration produced owing to a mass eccentricity of the disc. Thus, a disc drive which can make an extremely precise detection of a magnitude of vibration resulting from the mass eccentricity of the disc without using a sensor component for detecting the vibration can be provided.

Abstract: When a data is recorded to a recording medium, a miserasing preventing circuit determines whether or not a track jump is caused by a shock or a scratch. If it is caused by a shock, such as a quantity of light of an optical pick-up is controlled to change a reproducing state, and then the optical pick-up is moved to the rerecording position to start rerecording. As a result, recorded area is not disturbed, and the rerecording control is not performed by a little dust. Thereby, it can be provided an apparatus with high recording efficiency.

Abstract: In a method of the present invention for controlling stepping motor, the stepping motor driving current is increased or reduced at a fixed inclination in proportion to the time to control the stepping motor effectively, and, a stepping motor driving current pattern is changed by 1/4 cycle or over to synchronize the state of excitation between the stepping motor driving means and the stepping motor to control the pick-up very accurately. In addition, the disk apparatus of the present invention, which uses a stepping motor is provided with a pulse rate pattern variable means, a pulse rate change proportion measuring means, and a driving voltage variable means, and when the pulse rate and the pulse rate change proportion are low, the driving voltage amplitude is lowered to reduce surplus torque generation in the stepping motor.

Abstract: A correction processing unit for correcting a level fluctuation appearing on a tracking error signal when a laser beam passes an ID area on a medium track during an on-track control is provided. That is, in the correction processing unit, a correction value determined by a correction value determining unit at a correction timing detected by a correction timing discriminating unit is subtracted by a correcting unit from a signal value obtained by sampling and converting the tracking error signal into digital data by an A/D converter at a predetermined period and reading, thereby performing the correction.

Abstract: Disclosed is a seek control method in an optical storage device, of seek-moving a light beam of an optical head from a certain track on an optical storage medium to a desired track. This seek control method comprises a step of calculating a target position, a step of detecting a present position from a track error signal indicating a relative position between the light beam and the track, a step of calculating such a feedback control quantity as to zeroize an error between the target position and the present position and a step of controlling a moving mechanism for moving the light beam in accordance with the feedback control quantity.

Abstract: A malfunction during focussing pull-in in an optical disc recording/reproducing apparatus is to be prevented. To this end, the optical disc recording/reproducing apparatus includes an optical pickup 7 having an objective lens 8 and a biaxial actuator, a photodetector for generating tracking error signals from the return light of the laser light illuminated on the optical disc and a position sensor for detecting the position of the objective lens relative to the optical disc. The optical disc recording/reproducing apparatus also includes an actuator driving circuit for controlling the servo operation of a biaxial actuator 9, based on the tracking error signals, so that the converging point of the light beam will be on the signal recording surface of the optical disc, and a pull-in range decision unit for outputting a permission signal according permission for the servo operation when the position of the objective lens 8 is within a preset range.

Abstract: An optical pickup position control device according to the present invention automatically adjusts tracking with precision and in a short time. Two deviation signals, which express deviation of a light beam, projected by a pickup which uses the three-beam method, from a target track of a disk, are digitized by two AD converters. Two high-pass filters extract from the deviation signals AC signals, producing a tracking error signal. Further, two low-pass filters extract from the deviation signals DC signals (offset components). Two other low-pass filters extract from the deviation signals low-band signals containing DC components. Using the various foregoing signals, a control circuit calculates correction values to be applied to two offset correcting circuits and to two gain/balance correcting circuits, and corrections are performed collectively and simultaneously on the basis of these correction values.

Abstract: A tracking servo control method for preventing a tremble of an object lens installed in a pickup in an optical disk drive. A determination is made whether a distance between a target track and a current track where the pickup is presently placed is longer than a first distance. When the distance between the target track and the current track is longer than the first distance, both ends of a tracking coil through which a driving current for moving the object lens flows, are shorted. In the meantime, when the distance between the target track and the current track is shorter than a second distance as the pickup moves to the target track, both ends of the tracking coil are opened. The first distance is equivalent to a distance of 1000 tracks, and the second distance is equivalent to a distance of 100-200 tracks.

Abstract: A method and apparatus provides an improved optical storage disk player. An improved method and apparatus for obtaining a tracking error signal for an optical disk player is disclosed which is general across the various data formats found in CD audio disks, CD-ROMs, and digital video disks. The present invention uses a photodetector with at least four active areas to sense the reflected laser beam. A differential amplitude tracking error signal is generated by comparing the signal strength in the different active areas.

Abstract: A central servo control system is used in an optical disc drive to control an optical pickup head. The optical at least includes a lens. The central servo control system includes a radio frequency (RF) amplifier, a sled motor, a tracking coil, and a central servo controller. The RF amplifier chip is coupled to the optical pickup head so as to receive the optical signal, which is amplified and processed so as to produce a RF data signal, a tracking error (Te) signal, and a central servo (Tcs) signal. The sled motor is used to hold the optical pickup head and move the optical pickup head to a desired position. The tracking coil located on the optical pickup head is used to move the lens to a designed position so as to allow the optical signal to be easily detected by the optical pickup head. The central servo controller receives the RF data signal, the Te signal, and the Tcs signal from the RF amplifier chip, and accordingly exports a tracking control signal to the tracking coil.

Abstract: A reproducing apparatus and method are provided in accordance with the invention. The apparatus includes a reader for reading out data from a recording medium, a controller for controlling the position of the reader, and a determiner for determining a number of tracks the controller is to move the reader. The apparatus also includes a comparator, which compares whether the determined number of tracks is less than a predetermined number of tracks in which each of the tracks has an essentially equal number of sectors therein.

Abstract: A reproducing apparatus and method are provided in accordance with the invention. The apparatus includes a reader for reading out data from a recording medium, a controller for controlling the position of the reader, and a determiner for determining a number of tracks the controller is to move the reader. The apparatus also includes a comparator, which compares whether the determined number of tracks is less than a predetermined number of tracks in which each of the tracks has an essentially equal number of sectors therein. If so, the controller moves the position of the reader in accordance with the equation Tj=|St−Sc|/Sn wherein Tj is the number of tracks said reading means is to move, St is the address of the target sector to be read out next, Sc is the address of the current sector, and Sn is the essentially equal number of sectors in a track. A method utilizing the apparatus is also provided.

Abstract: A device for automatically controlling a sled loop gain in an optical disc drive having a sled motor.

Abstract: An optical information recording and reproducing method and device, whereby it is possible to prevent reduction in information recording capacity of an optical card and increase in recording and reproduction time due to track jump operations, and there is no occurrence of track jumping errors due to oscillations associated with acceleration and deceleration of the relative speed of movement between the optical card and an optical head. A region where the optical head and optical card are moved at a constant speed relative to each other is provided in the acceleration or deceleration of the relative speed of movement, and a track jump operation is implemented in this region.

Abstract: A disc apparatus includes a micro-computer. The micro-computer causes a pickup to move to a predetermined position. A track pitch is calculated from a distance over which the pickup has moved and a number of tracks detected during the movement thereof over that distance. In response to a track jump command, tracks to be jumped over are determined in number by the distance from a center of a disc to a current position, a distance from the center of the disc to a target position, and a track pitch measured.

Abstract: A control method for an optical disk drive is disclosed. In the control method, first and second light beams output from an optical head are irradiated to an optical disk. Information is recorded or reproduced using the first light beam, and information is deleted using the second light beam. The control method consists of steps described below. At a step, the moving velocity of the first light beam is calculated, and the moving velocity of the first light beam is controlled so that the moving velocity varies in conformity to a first velocity profile predetermined. Herein, the first velocity profile is pre-set to assist the first light beam in reaching a target track for the shortest time. At the next step, the position of the optical head is controlled so that the optical head follows the first light beam. At the next step, if the first light beam is accelerating or traveling at a constant velocity, the position of the second light beam is controlled so that the second light beam follows the optical head.

Abstract: The invention provides an optical disk medium having a recording spiral formed by connecting groove tracks and land tracks alternately, and permitting detection of a connecting point between a groove track and a land track reliably is provided, and a method of tracking the optical disk medium and an optical disk drive apparatus for driving the optical disk medium. One part of an identification signal area is shifted by a predetermined distance in one radial direction from the center of a groove, while another part of the identification signal area is shifted by the same distance in the opposite radial direction from the center of the groove. A land/groove polarity of a sector is determined by the polarity of a tracking error signal and the order of the polarities during reproduction of an identification signal.

Abstract: The present invention provides a method of determining a distance for moving an optical pick-up from a current track to a target track based on a distance from an exact single track width formed on an optical disc. According to the present invention, a method of determining a single track width of an optical disc by an optical pick-up includes the steps of a) calculating a number of tracks crossed by the pick-up using a detection of an initial track position information of an initial track when performing an initial loading of the disc and a track position information of a predetermined track located away the predetermined distance form the initial track; and b) calculating a single track width depending on the predetermined distance and the calculated number of tracks to be crossed by the pick-up. In the present invention, the access time of various optical discs is identical regardless the size of the single track width formed on the optical discs.

Abstract: An optical disk with clock pits disposed on tracks at predetermined intervals extending in a radial direction of the optical disk. Servo pits are arranged wobbly with respect to the tracks and auxiliary clock pits are arranged in such a manner that at least one auxiliary clock pit is provided between a pair of clock pits adjacent to one another in the radial direction of the optical disk.

Abstract: An adaptive, discrete-time sliding mode controller (SMC) is disclosed which detects and adapts to gain variations in the controlled plant. The overall control effort is generated by combining a linear control effort with a discrete-time sliding mode control effort generated by switching between gains in order to drive the system's phase states toward a sliding line trajectory. A sliding mode variable &sgr;k defines the position of the system phase states relative to the sliding line. The SMC controller is designed such that the sliding mode variable &sgr;k crosses the sliding line and changes sign at every sample interval. For the nominal plant gain, the SMC controller is also designed such that the magnitude of the sliding mode variable &sgr;k+1=−&sgr;k will remain constant (&sgr;k+1=−&sgr;k) and substantially constrained to |&sgr;k|=&Dgr;/(1+&lgr;) where &Dgr; and &lgr; are predetermined design constants.

Abstract: A CD-ROM drive is disclosed which is for use with disks having various degrees of spindle hole eccentricity and data track eccentricity. The hole eccentricity of each disk manifests itself during disk rotation as periodic vibration of the disk and, in consequence, periodic departures of the light beam spot from the track to an extent proportional to the speed of disk rotation, whereas the track eccentricity manifests itself during disk rotation as periodic departures of the beam spot from the track to a constant extent regardless of the speed of disk rotation. Therefore, on being loaded into the disk drive, each disk has its hole eccentricity and track eccentricity measured at two different disk eccentricity check speeds in terms of, for example, the amplitude of an eccentricity-caused periodic component of a tracking error signal. The hole eccentricity of the disk is ascertainable by subtracting the eccentricity measurement at the lower check speed from that at the higher check speed.

Abstract: A speed profile constituting the target speed for the next drive process during searching is generated by target speed generating section 140 and tracking actuator 132 is driven using the error signal in regard to the speed of movement of the light beam calculated by movement speed detection section 141 from a pulse signal obtained by converting the TE signal to binary form. Also linear motor 139 is driven using the difference signal obtained from the target speed and the speed of movement. Tracking actuator 132 is controlled so as to suppress swinging of focusing lens 107 during searching and linear motor 139 moves, during searching, under tracking control to a target speed.

Abstract: A tracking control apparatus for effectively compensating for a direct current offset of a tracking error signal when a recording medium having wobbled land and groove tracks is accessed. In the apparatus, a light beam is irradiated onto signal tracks of a recording medium including successively formed wobbled areas or intermittently formed wobbled areas, and a reflective light is detected by a photo detector divided into a plurality of areas. Signals detected by two areas of the photo detector symmetrically divided on a basis of the direction of the track are subtracted to generate a difference signal. Also, signals detected by the two area of the photo detector are added to generate a sum signal. A tracking offset compensating signal is generated based on the difference signal and the sum signal. The tracking error signal is compensated by the tracking offset compensating signal, so that a light beam can accurately trace the signal tracks.

Abstract: A magneto-optical information recording/reproducing apparatus in which a magneto-optical information recording medium at least including a first magnetic film having perpendicular magnetic anisotropy, and a second magnetic film to which information recorded on the first magnetic film is transferred by irradiation of a laser beam, is used so that a readout laser beam is irradiated onto the second magnetic film to thereby readout the information transferred to the second magnetic film. The apparatus includes a 2-split detection circuit for receiving the readout laser beam reflected from the second magnetic film of the recording medium, and a subtraction circuit in which output signals of the two detection elements of the 2-split detection circuit are subtracted from each other to generate a differential signal.