WO2000057411A1 - Lecteur d'informations enregistrees - Google Patents

Lecteur d'informations enregistrees Download PDF

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Publication number
WO2000057411A1
WO2000057411A1 PCT/JP1999/001372 JP9901372W WO0057411A1 WO 2000057411 A1 WO2000057411 A1 WO 2000057411A1 JP 9901372 W JP9901372 W JP 9901372W WO 0057411 A1 WO0057411 A1 WO 0057411A1
Authority
WO
WIPO (PCT)
Prior art keywords
objective lens
pickup
track
information
tracking
Prior art date
Application number
PCT/JP1999/001372
Other languages
English (en)
Japanese (ja)
Inventor
Hideaki Satou
Yoshimi Iso
Hiroshi Tadokoro
Masato Souma
Original Assignee
Hitachi, Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi, Ltd. filed Critical Hitachi, Ltd.
Priority to PCT/JP1999/001372 priority Critical patent/WO2000057411A1/fr
Publication of WO2000057411A1 publication Critical patent/WO2000057411A1/fr

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Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
    • G11B7/085—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam into, or out of, its operative position or across tracks, otherwise than during the transducing operation, e.g. for adjustment or preliminary positioning or track change or selection
    • G11B7/08505—Methods for track change, selection or preliminary positioning by moving the head
    • G11B7/08517—Methods for track change, selection or preliminary positioning by moving the head with tracking pull-in only

Definitions

  • the present invention relates to an optical disc device capable of reading information from a disc of a standard represented by CD-ROM (Compact Disk-Read Only Memory), DVD (Digital Video Disk), MD (Mini Disk), LD (Laser Disk), etc.
  • the present invention relates to a recording information reading apparatus applied to the above, and particularly to a drive control of a pickup and an objective lens at the time of a track access, and to a technology effective when applied to vibration suppression of an objective lens during a track access operation. is there. Background art
  • a spiral information track is formed on an optical disc such as a CD-ROM or a DVD.
  • An optical disk device that optically reads and reproduces information recorded on such an optical disk causes a pickup to follow a spiral information track while rotating the optical disk.
  • the optical disk device has a tracking unit for precisely positioning an objective lens in a pickup on a track, and a thread unit for traversing a plurality of tracks in a big up.
  • the objective lens is, for example, elastically supported by a frame of a pickup, and is configured to be movable in a cross-track direction within a predetermined movable range by an electromagnetic coil. This objective lens focuses the laser light on a very narrow information track.
  • Servo control is performed to operate the domo overnight so that the objective lens follows the information track.
  • a tracking servo for moving the objective lens on the big-up and a thread servo control for moving the objective lens together with the big-up so that the objective lens follows the information track are performed.
  • detection to detect the amount of displacement of the objective lens in the radial direction of the recording disk And use the output signal of the detector to track
  • a control technique for controlling the optical pickup and moving the optical pickup while keeping the lens relatively stationary with respect to the optical pickup is disclosed in Japanese Patent Publication No. 4-105525.
  • the displacement amount of the objective lens is not limited to the method of always suppressing the vibration of the objective lens by matching the acceleration of the objective lens and the pickup, or the control of always keeping the objective lens relatively stationary with respect to the pickup.
  • a lens position detector for detecting Requires a lens position detector for detecting.
  • the cost is high, and there is a problem that it cannot be applied to an optical pickup that does not have a lens position detector.
  • An object of the present invention is to provide a recording information reading apparatus capable of suppressing vibration of an objective lens during track access with a simple configuration without using a relative position detector for the objective lens.
  • the recorded information reading apparatus comprises an objective lens (5) elastically supported by a frame (105) and converging light toward the information recording medium (1), and traversing an information track of the information recording medium.
  • Tracking actuator as a first driving means capable of moving the objective lens in the direction (B) (2) having an evening (101a, 101b), and a transverse direction of the information track.
  • Pickup pickup means (8) as second driving means capable of moving the pickup, and servo control for operating the tracking lens and pickup pickup means so that the objective lens follows the track.
  • the control means performs the following control to suppress the vibration of the objective lens during the track access operation.
  • the control means detects a relative position of the objective lens on the pickup before opening the servo loop, and before moving the pickup by the pickup feeding means in the track traversing control,
  • the objective lens is moved toward its elastic neutral position by the tracking operation based on the detection result. According to the above, since the objective lens is forcibly returned to the elastic neutral position when the tracking servo is turned off, the elastic member supporting the objective lens is restored when the tracking servo is turned off. It is possible to suppress the objective lens from freely vibrating due to the force.
  • the detection of the relative position is performed only when the tracking servo is turned off, and is not necessary after the tracking servo is turned off. Therefore, the signal obtained during the tracking servo control can be used.
  • the objective This can be performed by detecting the amount of displacement of the lens from the elastic neutral position based on the drive signal (12 S) of the pickup feeding means during the servo control. Therefore, there is no need to newly provide a special position detection circuit to detect the relative position of the objective lens on the big-up.
  • the control means moves the objective lens in the same direction as the movement of the pickup by the tracking operation. Is performed temporarily.
  • the amount of movement at this time can be determined according to the mass of the big up, the moving speed, the moving distance, and the like.
  • the control unit controls the objective lens in a direction opposite to the moving direction of the pickup by the tracking acknowledgment at the time of braking for terminating the movement of the pickup.
  • the control for moving is temporarily performed.
  • the moving distance of the objective lens can be determined based on the strength of the brake applied to the big-up feeding means. According to this, it is possible to suppress occurrence of unnecessary vibration in the objective lens due to an inertial force generated by applying a brake to the pick-up feeding means near the end of the movement of the pickup.
  • the following control can be adopted as the vibration suppression control of the objective lens during the track access operation by the control means. That is, the control The means detects a relative position of the objective lens on the pick-up before the sub-volume is opened, and at the same time as control for starting movement of the pickup by the pick-up feeding means in the track crossing control. The objective lens is moved toward its elastic neutral position by the tracking operation based on the detection result. If this control is used, the time required for track access is reduced, but if the movement of the objective lens on the pickup and the movement of the pickup itself overlap, the control becomes complicated.
  • FIG. 1 is a block diagram showing an example of an optical disk device.
  • FIG. 2 is an external view illustrating the mechanical configuration of the pick-up feeding means.
  • FIG. 3 is an explanatory diagram illustrating a mechanical configuration of the objective lens driving device.
  • FIG. 4 is a frequency response characteristic diagram of an actuator for explaining the free vibration of the objective lens.
  • FIG. 5 is an explanatory diagram of a force generated by a difference in the relative position of the objective lens.
  • FIG. 6 is an explanatory diagram showing a waveform of a tracking drive control signal corresponding to the relative position of the objective lens during a normal reproduction operation.
  • FIG. 7 is an explanatory diagram showing waveforms of drive control signals in a thread mode and a tracking operation during a track access operation.
  • FIG. 8 is a flowchart showing a control procedure of the track access operation.
  • FIG. 9 is an explanatory diagram showing waveforms of drive control signals in a thread mode and a tracking operation in another example of the track access operation.
  • FIG. 1 is a block diagram showing an example of an optical disk device to which the present invention is applied.
  • an optical pickup also referred to as an optical pickup
  • a laser light source 3 a beam splitter 4
  • a condenser lens 5 also referred to as an objective lens
  • a photodetector 6 a photodetector 7.
  • a mechanical lens driving device 7 a mechanical lens driving device 8.
  • a laser light source 3 in the optical pickup 2 includes a laser diode (not shown), a driving circuit for emitting a laser diode, and a laser light source for converting divergent laser light emitted from the laser diode into parallel light. And a collimating lens (not shown) for emitting parallel laser light.
  • the optical path of the laser light is bent by the beam splitter 4 and is incident on the objective lens 5.
  • the objective lens 5 focuses the light beam and forms a minute light spot on the recording surface of the recording disk 1.
  • the light reflected on the recording surface of the recording disk 1 enters the photodetector 6 via the condenser lens 5 and the beam splitter 4.
  • the photodetector 6 receives the intensity change of the reflected light modulated by the track position information on the recording disk 1, and supplies the photoelectrically converted signal to the high-frequency amplifier 32.
  • the high-frequency amplifier 32 performs a current-voltage conversion process on the output signal of the photodetector 6, performs an addition / subtraction process, and changes a signal level and a polarity according to a shift amount between the objective lens 5 and the information track. Generate TE.
  • the lens driving device 7 supports the objective lens 5 visibly, and There is a tracking unit that allows the object lens 5 to move in the radial direction of the disk (in the transverse direction of the information track), and a focusing unit that allows the object lens 5 to move in the front and back directions of the disk. Doing
  • the tracking drive of the lens driving device 7 moves the focused light spot in the radial direction of the recording disk (the direction traversing the track) by moving the focusing lens 5 based on the tracking error signal TE. Move. Through this operation, tracking control, which will be described in detail later, is performed.
  • the high-frequency amplifier 32 includes a focus error signal FE whose signal level is changed according to the defocus amount (deviation from focus) of the laser beam from the output signal of the photodetector 6, and a return light signal FE. It also generates a data reproduction signal RF whose signal level changes according to the change in the polarization plane.
  • the optical disc device performs focus control by driving the focusing lens and moving the condenser lens 5 based on the focus error signal FE.
  • the illustration of the control circuit for the focus servo is omitted.
  • the data reproduction signal RF is supplied to the signal processing / reproduction circuit 33, which performs binarization and filtering by the digital signal processing, and performs decoding, error correction, format conversion, etc.
  • the data recorded on recording disc 1 is played back.
  • the reproduced data is supplied to a host device 34 such as a personal computer or a workstation via a system control unit 18.
  • the host device 34 gives an operation command @ control data to the optical disk device, controls its operation, and exchanges data with the optical disk device.
  • Tracking control during overnight playback >> Here, the tracking control will be described.
  • the switch 13 is connected to the thread control circuit 12 and the switch 15 is connected to the tracking actuator control circuit 11 so that the tracking servo loop is closed. It is performed in the state where it is.
  • a loop including the high-frequency amplifier 32, the tracking driver control circuit 11 and the driver driver 14 forms a first tracking sub-volume (track jump sub-loop).
  • a loop including the high-frequency amplifier 32, the tracking work control circuit 11, the thread motor control circuit 12, and the motor driver 9 forms a second tracking servo loop (thread feed servo loop).
  • the spot irradiated from the objective lens 5 onto the disc follows the information track by controlling the tracking error based on the tracking error signal TE output from the high-frequency amplifier 32. Control. In other words, if the tracking control is properly controlled by this tracking control, the position of the objective lens 5, that is, the position of the optical spot, can be stopped at a fixed position with respect to the pickup 2. it can.
  • a tracking error signal TE is input to a tracking work overnight control circuit 11 and a pulse generation circuit 30.
  • the output of the tracking driver control circuit 11 is supplied to a driver driver 14 via a switch 15 and the driver driver 14 drives the driver driver.
  • the tracking actuator control circuit 11 is designed to stabilize the tracking control, in other words, the difference between the optical spot and the information track detected by the tracking error signal TE. With characteristics designed to reduce For example, a known circuit configuration using phase lead / lag compensation or the like can be adopted.
  • the objective lens 5 is driven so as to follow the track by the tracking function.
  • the optical pickup 2 if the optical pickup 2 is stopped, the objective lens 5 gradually deviates from its center position on the big-up 2, and if it exceeds the movable range of the objective lens 5, it cannot follow the information track any longer.
  • the pickup 2 since the operation range of the objective lens 5 on the pickup 2 is limited, the pickup 2 is supported so as to be movable in the radial direction of the recording disk, and the pickup 2 is used as a thread mode as a big-up feeding means. It is configured to be able to move in the evening 8.
  • the tracking drive control signal TD output from the tracking actuator control circuit 11 passes through the thread mode control circuit 12 and the drive control signal SLD changes from the switch 13 to the thread mode 8. It is applied as
  • the thread monitor control circuit 12 adjusts and stabilizes the frequency characteristic so that the direct current component of the tracking drive control signal TD is stably absorbed by the thread monitor 8, and the second tracking signal is provided. This is to optimize the response in one step.
  • only the low frequency component of the drive control signal TD is applied as the drive signal SLD of the thread mode 8.
  • the optical spot can be moved slowly and largely by the thread monitor 8 and quickly and minutely by the tracking track.
  • the system control circuit 18, the lens control signal generator 16, the thread control signal generator 17, the pulse generator 30, the tracking control circuit 11, and the thread motor control circuit 1 are on one semiconductor chip
  • the control circuit 31 is a semiconductor integrated circuit.
  • the front switch 13 is connected to the thread control signal generator 17, and the switch 15 is connected to the lens control signal generator 16. That is, the first and second tracking lenses are opened (cut), and the system control section 18 is operated by the system controller 18 on the big lens 2 and the big lens 2 regardless of the tracking error signal TE. 5 can cross the track.
  • the system control unit 18 gives an instruction to the lens control signal generator 16 to instruct the number of traversing tracks when moving the objective lens on the pickup 2 to traverse the tracks. One night is driven.
  • the system control unit 18 gives an instruction to the thread control signal generator 17 when the big lens 2 is moved to cause the objective lens 5 to cross the track, and the thread control signal generator 17 responds to this. Is driven.
  • the actual number of track crossings according to the instruction is obtained by shaping the waveform of the tracking error signal TE, which is a periodic signal for each crossing, with the pulse generator 30 and converting the resulting pulse signal 30S into the system controller 18 It can be grasped by counting with.
  • the pickup 2 largely moves by the threading mode 8 according to the number of moving tracks, that is, the moving distance, and the objective lens 5 moves minutely by the tracking function, and the objective lens 5 moves to the target track. Positioned.
  • FIG. 2 shows an example of the mechanical configuration of the big-cap feed unit.
  • Recording disc 1 is mounted and fixed on turntable 22 and the disc is Spider rotated by 19th.
  • the rotational speed of the disk motor 19 is controlled, for example, at a constant linear velocity.
  • the feed shafts 20a and 20b serve to guide the pickup 2 linearly in the transverse direction of the track while supporting the big up 2, and constitute a so-called narrow guide.
  • the pickup 2 has a rack gear 23A, and the rotational force of the thread motor 8 is transmitted through a corresponding pinion gear 23B and an intermediate gear 23C concentrically fixed to the pinion gear 23B. It can be moved back and forth linearly.
  • the disk motor 19, the feed shafts 20a and 20b, the pinion gear 23B, the intermediate gear 23C, and the thread motor 8 are fixed to a support 21.
  • FIG. 3 exemplifies the mechanical configuration of the tracking lens and the focusing lens of the objective lens realized as the lens driving device 7.
  • the lens driving device 7 has a lens support 103 holding the objective lens 5 and a lens with one end of an elastic member 104 such as a wire fixed to the lens support 103 and the other end fixed to the fixing member 105. It has a support mechanism for elastically supporting the support 103.
  • the lens support 103 is provided with a focusing coil 102 and a tracking coil 101a, 101b with their cores orthogonal to each other, and further includes coils 102, 101a, Magnets 100a and 100b are arranged to face each other across 10 lb. Although the magnets 100a and 100b are illustrated as floating in FIG. 3, they are actually fixed to the fixing member 105.
  • the tracking coils 101a and 101b and the magnets 100a and 100b constitute a tracking actuator.
  • a restoring force of the elastic member 104 and a thrust by an electromagnetic force act on the objective lens 5.
  • the objective lens 5 is considered to be supported via the elastic member 104, and when the elastic member 104 is subjected to disturbances such as load, torsion, and deformation, and then removed, the objective lens 5 and the objective lens 5 are removed.
  • the elastic member 104 performs free vibration having a natural frequency determined by the mass of the object lens 5 and the elastic member 104 by a restoring force.
  • the swing width (displacement) and frequency of the vibration of the objective lens 5 supported by the elastic member 104 show, for example, the characteristics shown in FIG.
  • the frequency o indicates a peak of a free vibration inherent in the objective lens 5 supported by the elastic member 104, and is called a resonance point.
  • the objective lens 5 supported by the elastic member 104 can be modeled as a state in which both ends of the lens support are connected to a fixed member by a panel as shown in FIG.
  • FIG. 5 (2) shows a state in which the lens support 103 is stationary at the neutral position and no electromagnetic force or panel restoring force acts on the lens support 103.
  • (1) and (3) in FIG. 5 show that the lens support 103 is biased to one side or left and stationary, and the electromagnetic force and the restoring force of the panel are applied to the lens support 103. It is working.
  • the lens support 103 becomes elastically free and starts vibrating due to the restoring force of the panel.
  • FIG. 6 shows an example of the waveform of the drive control signal TD during the tracking operation.
  • FIG. 6 shows the waveform of the drive control signal TD when the objective lens maintains the neutral position of the pickup 2. That is, there is no offset with respect to the electrical midpoint.
  • FIG. 6 (b) shows the waveform of the drive control signal TD when the objective lens 5 is displaced to the left or right in the tracking direction, and has a high or low offset from the electrical midpoint. State.
  • FIG. 6 illustrates the waveform of the drive control signal SLD of the thread monitor 8 when the objective lens 5 is in the state of (b) of FIG.
  • the thread control signal SLD is a signal obtained by performing phase compensation on the low-frequency component of the drive control signal TD for the tracking operation, and This is a signal used to control the motor 8.
  • the signal waveform shown in (c) of FIG. 6 is proportional to the voltage applied to the thread motor 8.
  • the thread 8 has a dead zone, and rotates when the applied voltage exceeds the dead zone. It is assumed that the objective lens 5 is in a state as shown in (3) of FIG. 5 at the start of rotation. At this time, the thread will rotate 8
  • the objective lens 5 starts to return to the mechanical center position in the evening, that is, the neutral position, and passes the state of (2) in FIG.
  • the voltage to 8 is lowered to a level below the dead zone
  • the rotation of threaded motor 8 is stopped.
  • the objective lens 5 is in the state of (1) in FIG. 5, for example.
  • the drive control signal SLD of the threaded motor 8 can be regarded as a signal indicating the displacement of the objective lens 5 from the neutral position.
  • the states of the objective lens 5 in (1), (2) and (3) in FIG. 5 and the states of the waveforms in (b) and (c) in FIG. 6 correspond to (b) and (b) in FIG. (C) It can be associated as the positions of (1), (2), and (3) above.
  • the signal waveform in FIG. 6 is a signal waveform at the time of normal reproduction in which reproduction is performed by closing each loop of the track jump servo and the thread feed servo.
  • FIG. 7 shows the signal waveforms of the control signals S LD and TD when performing track access following the normal reproduction. Track access is started from time t0.
  • FIG. 8 shows an example of a control procedure of the system control unit 18 for an instruction of a track access operation.
  • the track access instruction is issued from the host device 34 by a command, etc.
  • the command includes target track number information and the like.
  • the system control unit 18 calculates the number of tracks to be moved with respect to the current position of the objective lens 5. The current position in this calculation can be ascertained based on track position information and the like included in the immediately preceding read information.
  • the system controller 18 counts the output pulse signal 30S of the pulse generator 30, compares the target number of traversing tracks with the counted value, and grasps the required number of traversing tracks.
  • the track error signal TE has a sinusoidal waveform that periodically changes every time the track crosses the track. Therefore, the track error signal TE is generated by the pulse generator 30.
  • the system controller 18 calculates the positional deviation (residual error) to the target track by calculating the number of pulses, and can use it for positioning.
  • the system control unit 18 detects the relative position of the objective lens 5 on the pickup 2 before opening the servo (S 1). That is, the current position of the objective lens 5 on the pickup 2 is detected.
  • the thread motor drive control signal SLD can be used for the detection.
  • the drive control signal SLD of the thread mode can be regarded as a signal indicating the amount of displacement of the objective lens 5 from the neutral position. Therefore, the midpoint potential is subtracted from the voltage value of the thread mode drive control signal SLD, and the value is converted into a displacement amount. That is, the amount of displacement of the objective lens 5 required to return the objective lens 5 to the elastic neutral position is calculated by the track jump using only the tracking error.
  • the system control unit 18 calculates the number N of tracks to be jumped with respect to the displacement amount, or calculates the number N using a conversion table.
  • the system control unit 18 gives the switches 13 and 15 an instruction to open the subvolume (OFF).
  • the objective lens 5 attempts to shift to the free state (S 3).
  • a track jump command is sent from the system controller 18 to the lens control signal generator 16 to execute the track jump for the N tracks calculated in the step S2 (S4).
  • the system controller 18 keeps counting the number of tracks traversed by the objective lens 5, and when the count value reaches a desired value, it is considered that the N-track jump has been completed. Even if the objective lens 5 is elastically free in step S3, the objective lens 5 is forcibly track-jumped to the elastic neutral position with respect to the pickup 2, so that the restoring force of the elastic member 104 Accordingly, free vibration of the elastic member 104 together with the objective lens 5 is suppressed.
  • the system controller 8 sends a thread mode 8 drive command signal to the thread control signal generator 17.
  • the thread control signal generator 17 gives a kick pulse to the thread motor 8 to start it, the thread motor 8 rotates, and the pickup 2 starts to move in the radial direction of the disk (S 5 ).
  • the kick-up 2 starts to move rapidly, the objective lens 5 in the kick-up 2 tries to stay there by the principle of inertia. In this state, if nothing is done, the objective lens 5 will be in the same state as (1) and (3) in FIG.
  • the system controller 18 determines that the target track has been approached while counting the number of traversing tracks while the pickup 2 is moving, and brakes the thread control signal generator 17 when a predetermined count value is reached. A command is issued to rapidly reduce the moving speed of the big up 2 (S7). Even if the upclose 2 is rapidly decelerated, the objective lens 5 in the upup 2 tries to keep moving by the principle of inertia. If the objective lens 5 remains as it is, the objective lens 5 will be (1) in FIG. The state becomes the same as that of (3), and a vibration is generated by receiving a restoring force from the elastic member 104.
  • the system controller 18 sends a kickback command to the lens control signal generator 16 so as to suppress the vibration of the objective lens 5, and temporarily moves the objective lens 5 in the opposite direction to the moving direction of the pickup 2. (S8).
  • This movement amount is calculated by the system control unit 18 based on the access distance (the number of crossing tracks) by the track access, the braking force, and the like. Instead of this calculation processing, the movement amount may be obtained by referring to a table.
  • FIG. 7 showing the waveforms of the control signals SLD and TD at the time of the above track access control
  • the control of steps S 1 and S 2 is performed before time t Is performed.
  • the tracking servo loop is cut off (S3), and following this, the track jump of step S4 is started.
  • the movement of the thread is started at time t1 (S5), and a key pulse is given to the tracking actuator to suppress the occurrence of vibration of the objective lens (S6).
  • a brake pulse is applied at time t2 at the end of track access (S7), a kickback pulse that generates a magnetic field in the opposite direction to the kick pulse is applied during the tracking operation, and the objective lens is driven. Vibration generation is suppressed (S8).
  • the servo loop is closed and the tracking servo is pulled in (S9).
  • FIG. 9 shows the timing of another control method in which the track jump for the tracking operation and the thread movement start timing for the thread mode are different from the above. That is, the difference from the control method of FIG. 7 is that the movement start instruction of the backup 2 using the thread mode 8 performed in step S5 and the tracking operation performed in step S4 are used. This is the same timing as the track jump.
  • step S4 The jump of the objective lens 5 in step S4 must be performed so as not to lose the inertial force generated in the operation of step S5, so the system controller 18 controls the lens control to satisfy this. It is necessary for the signal generator 16 to generate a drive control signal.
  • the detection of the relative position of the objective lens 5 with respect to the view-up 2 only needs to be performed when the tracking servo is turned off (Sl), and is not necessary after the tracking servo is turned off. Therefore, the relative position of the objective lens 5 can be detected by using the thread control signal SLD obtained during the tracking servo control. For example, it can be performed by detecting the amount of displacement of the objective lens from the neutral neutral position based on a signal 12S which is a drive control signal SLD of the thread motor 8 during the servo control. . Therefore, there is no need to newly provide a special position detection circuit for detecting the relative position of the objective lens 5 on the big-up 2.
  • the objective lens 5 When the servo loop is opened during track access, the objective lens 5 is returned to the elastic neutral position, so that the vibration of the objective lens 5 due to the restoring force of the elastic member 1Q4 can be suppressed.
  • the objective lens 5 When the pickup is moved, the objective lens 5 is temporarily moved in the same direction as the movement direction, so that unnecessary vibration that is generated in the objective lens 5 due to inertia at the start of the movement of the pickup is also suppressed. can do.
  • the control for giving a force against the inertial force to the objective lens is only temporarily performed at the start of the pickup movement following the operation of returning the objective lens 5 to the neutral position. Therefore, it is not necessary to constantly control the relative position of the objective lens with respect to the pickup or to maintain the acceleration of the objective lens constant during track access. Therefore, according to the present invention, the vibration of the objective lens at the time of access can be suppressed with a simple configuration without using a special relative position detector of the objective lens, and stable track access with reduced access time can be performed. Can be obtained.
  • the elastic neutral position of the pickup does not mean a mechanical neutral position (balance position) in a strict sense without error, but a range of required mechanical or electrical accuracy. Means the neutral position in the interior.
  • the mechanical or electromagnetic driving mechanism such as the pickup and the lens driving device is not limited to the above example, and can be appropriately changed.
  • the reading of the recorded information is not limited to the method using the constant linear velocity, and it is possible to employ an appropriate prescription such as a constant angular velocity or a mixture of both.
  • the recording medium is not limited to CD-ROM or DVD, but may be any writable medium such as MO or MD.
  • MO writable medium
  • the present invention can be applied to an information recording / reproducing apparatus having a writing function.
  • the control circuit 31 is not limited to a single-chip semiconductor integrated circuit, but may be a multi-chip single-chip microcomputer and a digital signal processor. Industrial applicability
  • the present invention is, CD- ROM, LD, MD S LV, CDV
  • the present invention can be widely applied to optical disk devices, magneto-optical disk devices, and the like that perform tracking control on a recording medium of a standard such as a DVD.
  • a pickup having a pickup, a pickup feeding means capable of moving the big pickup in a transverse direction of the information track, and the tracking lens and pickup sending means are operated to move the objective lens to the track.
  • the control means detects a relative position of the objective lens on the pick-up before opening the servo loop, and, based on the detection result, moves the pickup by the big-up feeding means in the track traversing control.
  • the relative position of the objective lens on the pick-up is an amount of displacement of the objective lens from a neutral neutral position, and the control means determines the amount of displacement by the pickup feed means during the servo control.
  • the control means may further include, in the track traversing control, when the pick-up movement is started, the tracking work temporarily controls the movement of the objective lens in the same direction as the pick-up movement direction.
  • Claim 1 characterized by the fact that

Abstract

L'invention concerne un lecteur d'informations enregistrées dans lequel un circuit de commande (31) détecte la position relative d'un objectif (5) avant qu'un actionneur de lecture du sillon et un moteur de mise en place (8) soient actionnés pour interrompre une boucle d'asservissement et suivre une piste, met l'objectif en position neutre élastiquement parlant en fonction du résultat de la détection avant qu'une tête de lecture (2) soit déplacée en fonction d'une commande de traversée de piste, et déplace l'objectif temporairement dans le sens de déplacement de la tête, lorsque la tête de lecture commence à se déplacer, ce qui empêche aisément une vibration libre de l'objectif, vibration qui serait autrement induite par une force de rappel élastique et une force d'inertie qui agissent sur l'objectif lorsque la boucle d'asservissement est interrompue.
PCT/JP1999/001372 1999-03-19 1999-03-19 Lecteur d'informations enregistrees WO2000057411A1 (fr)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07182662A (ja) * 1993-12-22 1995-07-21 Sony Corp 光ディスク装置
JPH0954962A (ja) * 1995-08-11 1997-02-25 Teac Corp ディスク装置

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07182662A (ja) * 1993-12-22 1995-07-21 Sony Corp 光ディスク装置
JPH0954962A (ja) * 1995-08-11 1997-02-25 Teac Corp ディスク装置

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