WO2007116684A1 - Objective lens driving apparatus - Google Patents

Objective lens driving apparatus Download PDF

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Publication number
WO2007116684A1
WO2007116684A1 PCT/JP2007/056205 JP2007056205W WO2007116684A1 WO 2007116684 A1 WO2007116684 A1 WO 2007116684A1 JP 2007056205 W JP2007056205 W JP 2007056205W WO 2007116684 A1 WO2007116684 A1 WO 2007116684A1
Authority
WO
WIPO (PCT)
Prior art keywords
objective lens
tracking
magnet
driving device
lens driving
Prior art date
Application number
PCT/JP2007/056205
Other languages
French (fr)
Japanese (ja)
Inventor
Takuya Wada
Hiroshi Yamamoto
Original Assignee
Matsushita Electric Industrial Co., 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 Matsushita Electric Industrial Co., Ltd. filed Critical Matsushita Electric Industrial Co., Ltd.
Publication of WO2007116684A1 publication Critical patent/WO2007116684A1/en

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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
    • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B7/0925—Electromechanical actuators for lens positioning
    • G11B7/0935—Details of the moving parts
    • 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
    • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B7/0925—Electromechanical actuators for lens positioning
    • G11B7/0933—Details of stationary parts
    • 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
    • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B7/0901—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for track following only
    • 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
    • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B7/0908—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for focusing only

Definitions

  • the present invention relates to an objective lens driving device for an optical head device provided in an optical disc apparatus that records or reproduces information on a disc-shaped optical recording medium such as a BD, DVD, or CD.
  • a disc-shaped optical recording medium such as a BD, DVD, or CD.
  • An optical disc device using a disc-shaped optical recording medium includes an optical head device for reproducing an information signal recorded on the optical disc or recording an information signal.
  • This optical head device includes a semiconductor laser that is a light source that emits a light bundle irradiated on an information recording surface of an optical disc, an optical system block that includes a light receiving element that converts return light from the optical disc into an electrical signal, and a semiconductor laser.
  • an objective lens driving device for converging the light beam emitted from the optical disk on the information recording surface of the optical disk by an object lens and for causing the light beam to follow the information track.
  • This objective lens driving device includes an orthogonal two-axis actuator mechanism that moves and adjusts the objective lens in the focusing direction and the tracking direction.
  • the focusing direction is a direction perpendicular to the information recording surface of the optical disc.
  • the tracking direction is a direction parallel to the information recording surface of the optical disk and perpendicular to the information track, that is, the radial direction of the optical disk.
  • a coil is arranged in a magnetic field, a control current is supplied to the coil, and the objective lens is moved using electromagnetic force generated in the coil. As a result, the objective lens is caused to follow surface deflection and eccentricity accompanying the rotation of the optical disk.
  • FIG. 11 is an overall perspective view showing an example of the configuration of a conventional objective lens driving device
  • FIG. 12 is a sectional view thereof.
  • the objective lens 101 is used for glass press or resin molding.
  • the lens holder 102 is formed by resin molding and fixed by adhesion.
  • a focusing coil 103 having a Z axis as a winding axis and tracking coils 104 and 105 having an X axis as a winding axis are bonded and fixed to the lens holder 102.
  • a balancer 106 for balancing the weight with the objective lens 101 is fixed to the lens holder 102.
  • the objective lens 101, the objective lens holder 102, the focusing coil 103, the tracking coils 104 and 105, and the tolerancer 106 constitute a movable part.
  • the elastic support member 107 is formed of a thin leaf spring material.
  • the elastic support member 107 has one end fixed to the objective lens holder 102 and the other end fixed to a fixing member 108 fixed to the base member 109.
  • This elastic support member 107 supports the movable part so as to be movable in the focusing direction (Z-axis direction) and the tracking direction (Y-axis direction).
  • the elastic support member 107 is formed by stamping a metal plate such as phosphor bronze or beryllium copper, which is excellent in both current-carrying properties and panel characteristics. Also do.
  • the base member 109 is made of a ferromagnetic metal such as iron.
  • the base member 109 sandwiches the focusing coil 103 and the tracking coils 104 and 105.
  • the base member 109 includes yokes 109a and 109b facing each other, and each of the yokes 109a and 109b has two magnetic flux directions in the X-axis direction and different magnetic poles on the surfaces facing each other.
  • a magnet 110 is bonded and fixed to form a magnetic circuit.
  • tracking coils 104 and 105 The currents flowing in the opposite directions to each other are supplied.
  • the moving part is tracked in the tracking direction (Y-axis direction) by the current flowing through the Z-axis direction parts 104a and 105a parallel to the optical axis of the objective lens 101 of the tracking coils 104 and 105 and the magnetic flux from the magnet 110 constituting the magnetic circuit. ) Is generated. Since the movable part including the lens holder 102 is movably supported by the elastic support member 107, the objective lens 101 fixed to the movable part is moved in the tracking direction orthogonal to the optical axis by this electromagnetic driving force. . The objective lens is moved in the tracking direction to adjust the tracking of the laser beam irradiated onto the optical disk.
  • the tracking coil 104, 105 has an electromagnetic driving force in the Z-axis direction due to the current flowing through the Y-axis direction parts 104b, 105b of the tracking coils 104, 105 and the magnetic flux of 110 magnets constituting the magnetic circuit. FZ occurs.
  • these electromagnetic driving forces FZ have the same magnitude in the brass direction and in the minus direction, cancel each other, and the resultant force becomes 0, and no force is generated to drive the movable part in the Z-axis direction.
  • the center of gravity of the movable portion and the support center that supports the movable portion of the elastic support member 107 are provided.
  • the center of the driving force generated by the tracking coils 104 and 105 (driving center) must be made to coincide with each other in a plane orthogonal to the direction of the displacement operation.
  • the objective lens 101 is disposed on the optical disc side (Z-axis direction plus side) of the movable part.
  • the center of gravity of the movable part and the support center of the elastic support member 107 are on the positive side in the Z-axis direction, and are shifted from the drive center of the tracking coils 104 and 105.
  • a balancer 106 made of brass or the like is fixed to the lower side (Z-axis direction minus side) of the lens holder 102 by bonding or the like, and the center of gravity and the support center are set as the tracking drive center by lowering the center of gravity of the movable part. Matched.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 11-167737
  • An object of the present invention is to solve the above-mentioned conventional problems, and without using a balancer.
  • Another object of the present invention is to provide a thin objective lens driving device in which the reproduction signal is hardly deteriorated.
  • An objective lens driving device is an objective lens driving device that drives an objective lens for optically recording or reproducing information on an optical recording medium
  • a lens holder to which an optical system including the objective lens is attached;
  • the lens holder includes a focusing direction perpendicular to the recording surface of the optical recording medium and a tracking direction perpendicular to the forcing direction.
  • a support member that elastically supports the fixing member so as to be movable in each direction;
  • At least a pair of first and second tracking coils having a winding axis parallel to a direction perpendicular to each of the focusing direction and the tracking direction, and fixed to the lens holder;
  • the drive center axes of the first and second tracking coils are defined as axes extending in the middle of the respective winding axes of the centers of the first and second tracking coils, and the drive center axes are Along with passing through the center of gravity of the objective lens driving device,
  • the magnet generates the electromagnetic force generated by the first and second tracking coils. It is characterized by having a magnetization pattern in which the total torque generated by is zero.
  • the support central axis of the objective lens driving device is defined as an axis that passes through the center of gravity of the objective lens driving device and extends perpendicular to a plane including the tracking direction and the focusing direction. it can.
  • the magnet may have a magnetization pattern corresponding to a distance between each portion of the first and second tracking coils facing the magnet and the support central axis.
  • the magnet is non-linear with respect to a line connecting the winding axes of the centers of the first and second tracking coils in a plane including the tracking direction and the focusing direction. It may have a symmetrical magnetization pattern.
  • the magnet may have a tapered shape in the focusing direction within a plane including the tracking direction and the focusing direction.
  • the magnet may have a convex shape in the focusing direction within a plane including the tracking direction and the focusing direction.
  • the magnet may include a first magnet that generates an electromagnetic force in the first tracking coil and a second magnet that generates an electromagnetic force in the second tracking coil.
  • the magnet may cause a magnetic flux parallel to each winding axis to act on the first and second tracking coils.
  • the magnet is within a plane including the tracking direction and the focusing direction.
  • the first and second tracking coils may have a line-symmetric magnetization pattern that intersects the drive center axis and is parallel to the focusing direction.
  • the magnet may have a magnetization pattern including a magnetized portion and a non-magnetized portion.
  • the magnet has a boundary of the magnetic pole inclined with the force in the focusing direction.
  • It may have a magnetized pattern with two poles.
  • an optical head device may include the objective lens driving device.
  • optical disk device according to the present invention may be provided with the optical head device. Good.
  • the objective lens driving device of the present invention does not need to match the tracking driving force center with the position of the center of gravity of the movable part and the center of the support, and therefore it is not necessary to add a balancer to the movable part. Therefore, it is possible to provide an optical disc apparatus that is thin and capable of obtaining high acceleration, that is thin and that has little deterioration in reproduction signals.
  • FIG. 1 is a schematic perspective view showing a configuration of an objective lens driving device according to Embodiment 1 of the present invention.
  • FIG. 2 is a cross-sectional view of a surface including a tracking coil of the objective lens driving device in FIG.
  • FIG. 3 is a schematic view showing the shape of the magnet of FIG.
  • FIG. 4 is a schematic diagram for explaining the tonolec to the support center of the electromagnetic driving force generated in the tracking coil of FIG.
  • FIG. 5 is a cross-sectional view of another objective lens driving device according to Embodiment 1 of the present invention.
  • FIG. 6 is a schematic perspective view showing a configuration of an objective lens driving device according to Embodiment 2 of the present invention.
  • FIG. 7 is a cross-sectional view of a surface including one tracking coil of the objective lens driving device of FIG.
  • FIG. 8 is a cross-sectional view of a surface including another tracking coil of the objective lens driving device of FIG.
  • FIG. 9 is a schematic view showing the shape of the tracking magnet of FIG.
  • FIG. 10 is a schematic diagram for explaining the torque with respect to the support center of the electromagnetic driving force generated in the tracking coil of FIGS. 7 and 8.
  • FIG. 11 is a perspective view of a conventional objective lens driving device.
  • FIG. 12 is a cross-sectional view of a surface including a tracking coil of the objective lens driving device in FIG.
  • FIG. 1 is a schematic perspective view showing the configuration of the objective lens driving device according to Embodiment 1 of the present invention.
  • FIG. 2 is a cross-sectional view of a surface including the pair of tracking coils 4 and 5 of the objective lens driving device of FIG. 1 and 2, an objective lens 1 formed by glass press or resin molding is fixed to a lens holder 2 by adhesion.
  • the lens holder 2 is formed by resin molding.
  • the lens holder 2 includes a focusing coil 3 with the Z-axis direction as the winding axis and two tracking coils 4 with the X-axis direction as the winding axis. , 5 is glued and fixed.
  • the objective lens 1, the objective lens holder 2, the focusing coinlet 3, and the tracking coils 4 and 5 constitute a movable part.
  • the elastic support member 7 is formed of a thin, leaf spring material.
  • the elastic support member 7 has one end fixed to the object lens holder 2 and the other end fixed to a fixing member 8 fixed to the base member 9.
  • the elastic support member 7 supports the movable part so as to be movable in the focusing direction (Z-axis direction) and the tracking direction (Y-axis direction).
  • the elastic support member 7 is formed by stamping a metal plate such as phosphor bronze or beryllium copper, which is excellent in both conductivity and panel characteristics.
  • a metal plate such as phosphor bronze or beryllium copper, which is excellent in both conductivity and panel characteristics.
  • One end of the elastic support member 7 is connected to the focusing coil 3 and the tracking coils 4 and 5 by soldering, and is configured to be electrically connected.
  • the base member 9 is made of a ferromagnetic metal such as iron.
  • the base member 9 includes yokes 9a and 9b facing each other with the focusing coil 3 and the tracking coils 4 and 5 sandwiched therebetween.
  • yokes 9a and 9b facing each other with the focusing coil 3 and the tracking coils 4 and 5 sandwiched therebetween.
  • two magnets 10 having a magnetic flux direction in the X-axis direction and different magnetic poles on the opposing surfaces are bonded and fixed to constitute a magnetic circuit.
  • the movable part When the current is supplied to the focusing coil 3, the movable part is driven in the focusing direction by the current flowing in the focusing coil 3 and the magnetic flux in the X-axis direction from the magnet 10 constituting the magnetic circuit. Generate electromagnetic driving force. Since the movable part including the lens holder 2 is movably supported by the elastic support member 7, the objective lens 1 fixed to the movable part is moved in the focusing direction parallel to the optical axis by this electromagnetic driving force. To do. The objective lens 1 is moved in the focusing direction to adjust the focusing of the laser beam irradiated on the optical disk.
  • the drive center axis of the tracking coils 4 and 5 is defined as an axis extending in the middle of each winding axis at the center of the tracking coils 4 and 5.
  • the drive center is defined as the point where the drive center axis intersects the plane including the focusing direction (Z-axis direction) and the tracking direction (Y-axis direction). That is, it is defined as the point where the plane including the tracking coils 4 and 5 intersects with the drive center axis.
  • the objective lens driving device according to Embodiment 1 is not provided with a balancer. Since no balancer is provided, as shown in FIG. 2, the center of gravity of the movable part and the position of the support center G that supports the movable part of the elastic support member 7 are in the Z-axis direction of the objective lens 1 of the tracking coils 4 and 5. It is located on the positive side in the Z-axis direction from the center position (drive center) of the Z-axis direction parts 4a and 5a parallel to the optical axis. That is, the support center of the objective lens driving device and the driving center of the tracking coils 4 and 5 are deviated.
  • Torque TZa is generated (Fig. 2). This torque TZa causes the movable part to rotate about the X axis and causes the optical axis of the object lens 1 to tilt.
  • the electromagnetic driving force generated by the tracking coils 4 and 5 is affected by magnetic flux in addition to the electromagnetic driving force FY in the tracking direction (Y-axis direction) by the portions 4a and 5a in the Z-axis direction.
  • the torque TZb around the support center is also generated for this electromagnetic driving force FZ in the Z-axis direction. Therefore, the present inventor controls the electromagnetic driving force FZ in the Z-axis direction generated by the portion in the Y-axis direction, so that the Tonlek TZa by the electromagnetic driving force FY in the Y-axis is rotated by the clockwise torque T Zb. I came up with the idea of offsetting the total torque to 0.
  • the present inventor uses the inverted trapezoidal magnet 10 as shown in Fig. 3 to control the electromagnetic driving force generated in the Y axis direction portions 4b, 4c, 5b, 5c of the tracking coins 4, 5 Think to do #2.
  • the yokes 9a and 9b and the magnet 10 have an inverted trapezoidal cross-sectional shape in which the dimension of the upper base is larger than the lower base in the Z-axis direction.
  • the magnitude of the electromagnetic driving force increases in proportion to the length of the part where the magnetic flux acts. That is, the magnitude of the electromagnetic driving force generated in the tracking coils 4 and 5 varies depending on the length of the portion where the magnetic flux acts by the magnet 10.
  • the shape of the magnet 10 a trapezoidal shape with a long upper side and a short lower side, the length of the magnetic flux applied to the portions 4b, 4c, 5b and 5c in the Y-axis direction of the tracking coils 4 and 5 can be controlled. .
  • a clockwise tonlek TZb is generated and the Y-axis electromagnetic driving force FY torque Force S to offset TZa and make the total torque of the whole zero.
  • FIG. 4 is a schematic diagram for explaining the electromagnetic driving force generated in the pair of tracking coils 4 and 5 in FIG. 2 and the torque with respect to the support center G by this electromagnetic driving force.
  • the tracking coils 4 and 5 are indicated by dotted lines.
  • the electromagnetic drive force generated in each part of the tracking coils 4 and 5 where the magnetic flux acts by the magnet in Fig. 3 is indicated by arrows.
  • the solid line from the support center to the point of action of the electromagnetic driving force is shown.
  • the counterclockwise tonnolek TZa is generated about the support center G by the electromagnetic driving forces FY1 and FY2 generated in the Z-axis direction parts 4a and 5a of the tracking coils 4 and 5.
  • a magnetic flux of 10 magnets also acts on the apportionments 4b, 4c, 5b and 5c in the Y-axis direction of the tracking coinlets 4 and 5.
  • electromagnetic driving forces FZ1, FZ2, FZ3, and FZ4 in the Z axis direction are generated in the Y axis direction parts 4b, 4c, 5b, and 5c. Since the support center G and the drive center are misaligned in the Z-axis direction, torque is also generated for the electromagnetic drive force in the Z-axis direction. This torque is expressed as the vector product of the distance vector from the support center G and the force vector.
  • the magnet 10 has an inverted trapezoidal shape in the plane including the tracking direction and the focusing direction, as shown in FIG.
  • Electromagnetic driving force is , And increases in proportion to the length of magnetic flux.
  • the parts 4b and 5b are longer than the parts 4c and 5c. Therefore, the electromagnetic driving forces FZ1 and FZ3 generated in the parts 4b and 5b are larger than the electromagnetic driving forces FZ2 and FZ4 generated in the parts 4c and 5c.
  • the support center G is off the plus side in the Z-axis direction from the drive center, the parts 4b and 5b are closer to the support center G than the parts 4c and 5c.
  • the length of the portions 4b, 4c, 5b, 5c is controlled by controlling the shape of the magnet according to the distance from the support center G.
  • the size of the electromagnetic drive FZ1, FZ2, FZ3, FZ4 in the Z-axis direction is controlled by the length of the parts 4b, 4c, 5b, 5c.
  • the sum of the torque generated by the electromagnetic driving forces FZ1, FZ2, FZ3, and FZ4 in the Z-axis direction is defined as torque TZb.
  • This torque TZb has the opposite direction to the counterclockwise torque TZa generated by the Z-axis direction parts 4a and 5a of the tracking coils 4 and 5, that is, the clockwise direction around the X axis with respect to the support center G. Like that.
  • the magnitude of the clockwise torque TZb by the Y-axis direction parts 4b, 4c, 5b, and 5c is controlled to be the same magnitude as the counterclockwise torque TZa by the Z-axis direction parts 4a, 5a. .
  • the torques TZa and TZb in the two opposite directions cancel each other and can be reduced to substantially zero. Therefore, the inclination of the objective lens 1 due to the rotation of the movable part can be suppressed.
  • the resultant force of the electromagnetic driving force generated in the tracking coils 4 and 5 must be only the resultant force in the Y-axis direction, which is the tracking direction, and the resultant force in the Z-axis direction must be 0. . Therefore, consider the resultant force in each direction.
  • an electromagnetic drive force of (FY1 + FY2) is generated as described above.
  • the magnet 10 has a line-symmetric shape with respect to a line parallel to the Z-axis direction in the YZ plane, that is, a line-symmetric magnetization pattern.
  • the lengths of the parts 4b and 5b in the Y axis direction are made the same, and the lengths of the parts 4c and 5c are made the same. Therefore, the electromagnetic driving force FZ1 generated in the part 4b is the same in the opposite direction to the electromagnetic driving force FZ3 generated in the part 5b. Further, the electromagnetic driving force FZ2 generated in the portion 4c is the same in the opposite direction to the electromagnetic driving force FZ4 generated in the portion 5c. Therefore, the resultant force of electromagnetic driving force in the Z-axis direction is zero. The resultant electromagnetic drive force generated in the tracking coils 4 and 5 is only in the Y-axis direction, which is the tracking direction.
  • the magnet 10 The cross section has an inverted trapezoidal shape.
  • the shape of the magnet 10 is controlled in consideration of the distance from the support center G.
  • the lengths of the tracking coils 4, 5 in the Y-axis direction 4b, 4c, 5b, 5c are controlled.
  • the electromagnetic driving force FZ in the Z-axis direction is controlled by the length of the parts 4b, 4c, 5b, and 5c.
  • the total torque around the support center G is controlled by making the direction of Tonlek TZb by the electromagnetic driving force FZ in the Z-axis opposite to that of Tonlek TZa by the Y-axis electromagnetic driving force FY and controlling it to the same magnitude.
  • the force in which the cross section in the X-axis direction of the magnet 10 has a trapezoidal shape may be a reverse convex shape as shown in FIG.
  • the length of the magnetic flux acting on the Y-axis direction parts 4b, 4c, 5b, and 5c of the tracking coils 4 and 5 can be controlled, and the clockwise tonlect TZb can be generated about the support center. The same effect can be obtained.
  • the shape of the tracking coils 4 and 5 is substantially rectangular.
  • the shape is not limited to this, and the same effect can be obtained even if the shape is circular or oval.
  • FIG. 6 is a schematic perspective view showing the configuration of the objective lens driving device according to Embodiment 2 of the present invention.
  • FIG. 7 is a cross-sectional view showing a surface including the tracking coil 25.
  • FIG. 8 is a cross-sectional view showing a surface including the tracking coil 26.
  • this objective lens driving device is different in that the focusing coils 23 and 24 have a winding axis in the X-axis direction like the tracking coils 25 and 26. To do.
  • this objective lens driving device is different from the objective lens driving device according to Embodiment 1 in that the two tracking coils 25 and 26 are provided on opposite surfaces of the lens holder 22 on the same surface. No. Another difference is that tracking magnets 32 and 33 for applying magnetic flux to the tracking coils 25 and 26 are provided as separate magnets. In the objective lens driving device according to Embodiment 2, the tracking magnets 32 and 33 have a magnetization pattern in which the magnetic poles are reversed on the surfaces 32a and 33a inclined in the Y-axis direction from the ZX plane.
  • An objective lens 21 formed by glass press or resin molding is fixed to the lens holder 22 by adhesion.
  • the lens holder 22 is formed by resin molding, and focusing coils 23 and 24 having a winding axis in the X-axis direction ⁇ and tracking coinoles 25 and 26 having a winding axis in the X-axis direction are bonded and fixed. Yes.
  • a focusing coil 23 and a tracking coil 25 are provided on one surface, and a focusing coil 24 and a tracking coil 26 are provided on the other surface.
  • the objective lens 21, the objective lens holder 22, the focusing coils 23 and 24, and the tracking coils 25 and 26 constitute a movable part.
  • the elastic support member 27 is formed of a thin leaf spring material.
  • the elastic support member 27 has one end fixed to the objective lens holder 22 and the other end fixed to a fixing member 28 fixed to the base member 29.
  • the elastic support member 27 supports the movable part so as to be movable in the focusing direction (Z-axis direction) and the tracking direction (Y-axis direction).
  • the elastic support member 27 is formed by stamping a metal plate such as phosphor bronze or beryllium copper, which is excellent in both conductivity and panel characteristics, by pressing. One end of the elastic support member 27 is connected to the forcing coils 23 and 24 and the tracking coils 25 and 26 by soldering, and is configured to be energized.
  • the base member 29 is made of a ferromagnetic metal such as iron.
  • the base member 29 is provided with yokes 29a and 29b at positions facing the focusing coils 23 and 24 and the tracking coins 25 and 26, respectively.
  • a focusing magnet 30 and a tracking magnet 32 are bonded and fixed to the yoke 29a on surfaces facing the focusing coil 23 and the tracking coil 25, respectively.
  • a focusing magnet 31 and a tracking magnet 33 are bonded and fixed to the yoke 29b on the surfaces facing the focusing coil 24 and the tracking coil 26, respectively.
  • the tracking magnets 32 and 33 have a magnetization pattern in which the magnetic poles are reversed with respect to the surfaces 32a and 33a inclined in the Y-axis direction from the ZX plane force.
  • the force magnetization pattern showing N pole and S pole as magnetic poles is not limited to the above case. Change the magnetization pattern appropriately according to the direction of current. Good.
  • This objective lens driving device has two driving systems each composed of a pair of focusing coils and tracking coils.
  • the first drive system includes a focusing coil 23, a forcing single magnet 30, a tracking coil 25, and a tracking magnet 32.
  • the second drive system includes a focusing coil 24, a focusing magnet 31, a tracking coil 26, and a tracking magnet 33.
  • the first drive system and the second drive system are arranged symmetrically around the optical axis (Z axis) of the objective lens 21 by 180 degrees.
  • FIG. 7 is a cross-sectional view of the surface including the focusing coil 23 and the tracking coil 25 of the objective lens driving device of FIG. 6 as seen from the plus side in the X-axis direction.
  • the movable part is indicated by a solid line
  • the focusing magnet 30, the tracking magnet 32, and the yoke 29a are indicated by a broken line.
  • FIG. 8 is a cross-sectional view of the surface including the focusing coil 24 and the tracking coil 26 of the objective lens driving device of FIG. 6 as viewed from the minus side in the X-axis direction.
  • the movable part is indicated by a solid line
  • the focusing magnet 31, the tracking magnet 33, and the yoke 29b are indicated by broken lines.
  • the focusing magnet 30 is magnetized with two poles in the X-axis direction so as to have a magnetic pole boundary 30a on a plane parallel to the flange surface.
  • the magnetic flux in the X-axis direction opposite to each other passes through the portion 23a and the portion 23b in the Y-axis direction of the focusing coil 23.
  • the current flowing in the focusing coil 23 and the magnetic flux of the focusing magnet 30 constituting the magnetic circuit cause the Y-axis direction portions 23a and 23b of the focusing coil 23 to Generates an electromagnetic drive force that drives the movable part in the Z-axis direction, that is, the focusing direction.
  • the focusing coil 24 also moves the movable part in the Z-axis direction, that is, the force-singing direction by the magnetic force in the X-axis direction from the focusing force magnet 31 constituting the magnetic circuit. Generates electromagnetic driving force to drive. Since the movable part including the lens holder 22 is movably supported by the elastic support member 27, the focusing coil 2 The objective lens 21 is moved in the focusing direction parallel to the optical axis by the electromagnetic driving force of 3 and 24. The objective lens 21 is moved in the focusing direction to adjust the focusing of the laser beam irradiated onto the optical disc.
  • the tracking magnet 32 is magnetized with two poles in the X-axis direction so that it has a magnetic pole boundary 32a on a surface slightly inclined in the Y-axis direction around the ZX surface force X-axis. Yes.
  • the magnetic flux in the X-axis direction opposite to each other passes through the portion 25a and the portion 25b in the Z-axis direction of the tracking coil 25.
  • an electromagnetic drive in the Y-axis direction is generated by the current flowing through the Z-axis direction portions 25a and 25b of the tracking coil 25 and the magnetic flux from the tracking magnet 32 constituting the magnetic circuit.
  • Force FY is generated. This electromagnetic driving force FY drives the movable part in the tracking direction (Y-axis direction).
  • the tracking coil 26 similarly has an electromagnetic driving force that drives the movable part in the Y-axis direction, that is, the tracking direction, by the magnetic flux in the X-axis direction from the tracking magnet 33 that forms the magnetic circuit. Generate FY. Since the movable part including the lens holder 22 is movably supported by the elastic support member 27, the objective lens 21 moves in the tracking direction orthogonal to the optical axis by the electromagnetic driving force FY by the tracking coils 25 and 26. The The objective lens 21 is moved in the tracking direction to adjust the tracking of the laser beam applied to the optical disk.
  • the Tonerek TZa around the right-hand thread in this X-axis direction causes the movable part to rotate around the X-axis, causing the optical axis of the objective lens 21 to tilt.
  • the tracking coil 25 has not only portions 25a and 25b in the Z-axis direction but also portions 25c, 25d, 25e and 25f in the Y-axis direction where the magnetic flux from the tracking magnet 32 acts.
  • the electromagnetic driving forces FZ1, FZ2, FZ3, and FZ4 in the Z axis direction indicated by the arrows in FIG. 7 are applied to the Y axis direction portions 25c, 25d, 25e, and 25f. appear.
  • the present inventor uses a tracking magnet 32 having a magnetization pattern in which the magnetic poles are reversed with respect to a surface 32a inclined to the negative side in the Y-axis direction from the ZX plane, and a similar tracking magnet 33. Therefore, we considered controlling the electromagnetic driving forces FZ1 to FZ8 generated in the Y-axis direction of the tracking coils 25 and 26.
  • Electromagnetic drive forces FZ3 and FZ4 forces S in the negative direction of the Z axis are generated in the Y axis direction parts 25e and 25f of the tracking coil 25.
  • Electromagnetic driving forces FZ1 and FZ2 in the positive direction of the Z axis are generated in the portions 25c and 25d.
  • the magnitude of the generated electromagnetic driving force increases in proportion to the length affected by the magnetic flux.
  • the tracking magnet 32 has a magnetic pole boundary on a surface 32a inclined from the ZX plane to the negative side in the Y-axis direction. Therefore, the portions 25c and 25d are longer than the portions 25e and 25f.
  • the electromagnetic driving forces FZ1 to FZ4 are controlled by controlling the lengths of the portions 25c, 25d, 25e, and 25f in the Y-axis direction.
  • the electromagnetic driving forces FZ1 to FZ4 are controlled so that the torque TZb by the electromagnetic driving forces FZ1 to FZ4 is opposite to the torque TZa by the portions 25a and 25b in the Z-axis direction and has the same magnitude.
  • the torque TZa is offset by the torque TZb, and the overall torque can be reduced to zero.
  • the tracking magnet 33 is opposite to the tracking magnet 32.
  • the surface 33a inclined to the plus side of the direction has a magnetic pole boundary. Therefore, the parts 26c and 26d are longer than the parts 26e and 26f.
  • the length of the portions 26c, 26d, 26e, and 26f in the Y-axis direction is controlled to control the electromagnetic driving forces FZ5 to FZ8.
  • the torque TZb force by the electromagnetic driving force FZ5 to FZ8 is controlled to have the same magnitude in the opposite direction to the torque TZa by the portions 26a and 26b in the Z-axis direction. As a result, the torque TZa is offset by the torque TZb, and the entire tonolek can be made zero.
  • the resultant force of the electromagnetic driving force generated in the tracking coils 25 and 26 must be only the resultant force in the Y-axis direction, which is the tracking direction, and the resultant force in the Z-axis direction must be zero. . Therefore, consider the resultant force in each direction.
  • the electromagnetic driving force FY1 + FY2 + FY3 + FY4 is generated as described above.
  • the tracking coil 25 a positive component in the Z-axis direction remains in the resultant force of the electromagnetic driving forces FZ1 to FZ4 in the Z-axis direction.
  • the negative force component in the Z-axis direction remains in the resultant force of the electromagnetic driving forces FZ5 to FZ8 in the Z-axis direction. Therefore, the boundary surfaces 32a and 33a of the magnetic poles of the tracking magnets 32 and 33 are controlled so that the portion 25c of the tracking coil 25 and the corresponding portions of the tracking coil 26 have the same length. As a result, the resultant force SO of the electromagnetic driving forces FZ1 to FZ8 in the Z-axis direction of the tracking coil 25 and the tracking coil 26 is obtained.
  • the tracking magnet 32 and the tracking magnet 33 are arranged so that the boundary surfaces 32a and 33a of the magnetic poles are symmetrical with respect to the ZX plane.
  • FIG. 10 is a schematic diagram for explaining the torque with respect to the support center G due to the electromagnetic driving force generated in the tracking coils 25 and 26 in FIGS. 7 and 8.
  • the tracking coils 25 and 26 are indicated by dotted lines.
  • the electromagnetic driving force generated in each part of the tracking coils 25 and 26 in FIGS. 7 and 8 is indicated by arrows.
  • the straight line from the support center to the point of action of the electromagnetic driving force is shown.
  • the electromagnetic driving forces FZ1 to FZ8 in the Z-axis direction generated in the Y-axis portions 25c to 25f and 26c to 26f of the tracking coils 25 and 26 have the following relationship.
  • the position shift occurs.
  • This misalignment generates Tonlek TZa around the support center G around the right-hand thread.
  • the second embodiment is characterized in that the tracking magnets 32 and 33 each have a two-pole magnetization pattern having a magnetic pole boundary on a surface inclined about the X axis from the XZ plane.
  • the electromagnetic drive forces FZ1 to FZ8 generate a tonolek TZb that is opposite in direction to the torque TZa and has the same magnitude.
  • Torque TZa can be offset by torque TZb, and the overall tonolec can be reduced to zero. This can suppress the tilt of the objective lens that occurs during tracking drive. Thereby, the inclination of the optical axis of the objective lens 21 due to the rotation of the movable part can be suppressed.
  • the tracking magnets 32 and 33 have a magnetic pole boundary on the surface inclined from the XZ plane around the X axis.
  • the force is not limited to this.
  • the tracking magnets 32 and 33 are two-pole magnetized so that the lengths of the upper and lower sides of the same magnetic pole facing the tracking coils 25 and 26 are different, and the middle part has a crank-shaped magnetic pole boundary. Moyore.
  • the Y-axis portion of the tracking coil can generate the same magnitude of torque TZb in the reverse direction of the torque TZa at the support center, and the same effect can be obtained.
  • the shapes of the tracking coils 25 and 26 are substantially rectangular. However, the shape is not limited to this, and the same effect can be obtained even if the shape is circular or oval.
  • the objective lens driving device can be incorporated into the optical head device.
  • this optical head device can be incorporated into an optical disk device.
  • the objective lens driving device it is not necessary to match the positions of the tracking driving force center, the center of gravity of the movable part, and the supporting center. Therefore, it is possible to obtain a thin and high acceleration that does not require the addition of a balancer to the movable part, and it can be used for an optical disc apparatus that is thin and has little deterioration in the reproduction signal.

Landscapes

  • Optical Recording Or Reproduction (AREA)

Abstract

Provided is an objective lens driving apparatus for driving an objective lens for optically recording/reproducing information in and from an optical recording medium. The objective lens driving apparatus is provided with a lens holder to which an optical system including an objective lens is attached; a supporting member, which has one end attached to the lens holder and the other end attached to a fixed member and elastically supports the lens holder to the fixed member so that the lens holder can move in a focusing direction vertical to the recording surface of the optical recording medium and in a tracking direction vertical to the focusing direction; first/second tracking coils, which have winding axes parallel to the directions vertical to the focusing direction and the tracking direction and are fixed to the lens holder; and a magnet for giving magnetic field to each tracking coil to have the tracking coil generate electromagnetic force. A drive center axis is specified as an axis extending to the middle of each winding axis of each tracking coil. The drive center axis does not pass the center of gravity of the objective lens driving apparatus, and the magnet has a magnetization pattern wherein the total torque due to electromagnetic force generated by each tracking coil is 0.

Description

明 細 書  Specification
対物レンズ駆動装置  Objective lens drive
技術分野  Technical field
[0001] 本願 ίま、 曰本国 (こ 2006年 3月 27曰（こ出願した特願 2006— 84573号の日本特許 出願を優先権主張の基礎とするものであり、この日本特許出願の内容は本願明細書 の一部をなすものとしてここに挙げておく。  [0001] This application is based on the Japanese patent application of Japanese Patent Application No. 2006-84573 (this application was filed on March 27, 2006). Listed here as part of the specification.
[0002] 本発明は、 BD、 DVD, CDなどの円盤状の光記録媒体に情報を記録または再生 する光ディスク装置に備える光学ヘッド装置用の対物レンズ駆動装置に関する。 背景技術  The present invention relates to an objective lens driving device for an optical head device provided in an optical disc apparatus that records or reproduces information on a disc-shaped optical recording medium such as a BD, DVD, or CD. Background art
[0003] 円盤状の光記録媒体 (以下、光ディスクと略す。）を用いる光ディスク装置は、光デ イスクに記録された情報信号を再生し、或いは情報信号を記録するための光学ヘッド 装置を備えている。この光学ヘッド装置は、光ディスクの情報記録面に照射される光 束を出射する光源となる半導体レーザや、光ディスクからの戻り光を電気信号に変換 する受光素子などからなる光学系ブロックと、半導体レーザから出射された光束を対 物レンズによって光ディスクの情報記録面に集光させるとともに、情報トラックに光束 を追従させる対物レンズ駆動装置とからなる。  [0003] An optical disc device using a disc-shaped optical recording medium (hereinafter abbreviated as an optical disc) includes an optical head device for reproducing an information signal recorded on the optical disc or recording an information signal. Yes. This optical head device includes a semiconductor laser that is a light source that emits a light bundle irradiated on an information recording surface of an optical disc, an optical system block that includes a light receiving element that converts return light from the optical disc into an electrical signal, and a semiconductor laser. And an objective lens driving device for converging the light beam emitted from the optical disk on the information recording surface of the optical disk by an object lens and for causing the light beam to follow the information track.
[0004] この対物レンズ駆動装置は、フォーカシング方向とトラッキング方向とについて対物 レンズを移動調整する、直交 2軸ァクチユエータ機構を備えている。なお、フォーカシ ング方向は、光ディスクの情報記録面と垂直な方向である。トラッキング方向は、光デ イスクの情報記録面と平行、且つ、情報トラックと直交する方向、すなわち光ディスク の半径方向である。この対物レンズ駆動装置では、磁界中にコイルを配置しており、 このコイルに制御電流を給電し、該コイルに生じる電磁力を利用して対物レンズを移 動させる。これによつて、対物レンズを光ディスクの回転に伴う面振れと偏心に追従さ せる。 [0004] This objective lens driving device includes an orthogonal two-axis actuator mechanism that moves and adjusts the objective lens in the focusing direction and the tracking direction. Note that the focusing direction is a direction perpendicular to the information recording surface of the optical disc. The tracking direction is a direction parallel to the information recording surface of the optical disk and perpendicular to the information track, that is, the radial direction of the optical disk. In this objective lens driving device, a coil is arranged in a magnetic field, a control current is supplied to the coil, and the objective lens is moved using electromagnetic force generated in the coil. As a result, the objective lens is caused to follow surface deflection and eccentricity accompanying the rotation of the optical disk.
[0005] 図 11、図 12を用いて、従来の対物レンズ駆動装置の構成について説明する。図 1 1は、従来の対物レンズ駆動装置の構成の一例を示す全体斜視図であり、図 12は、 その断面図である。図 11において、対物レンズ 101はガラスプレス又は樹脂成形に より形成されており、樹脂成形で形成されたレンズホルダ 102に接着により固定され ている。レンズホルダ 102には、 Z軸を卷回軸とするフォーカシングコイル 103と、 X軸 を卷回軸とするトラッキングコイル 104、 105とが接着固定されている。レンズホルダ 1 02には対物レンズ 101との重量バランスを取るためのバランサ 106が固定されている 。対物レンズ 101、対物レンズホルダ 102、フォーカシングコイル 103、トラッキングコ ィノレ 104、 105、ノ ランサ 106により、可動部が構成される。 The configuration of a conventional objective lens driving device will be described with reference to FIGS. 11 and 12. FIG. 11 is an overall perspective view showing an example of the configuration of a conventional objective lens driving device, and FIG. 12 is a sectional view thereof. In Figure 11, the objective lens 101 is used for glass press or resin molding. The lens holder 102 is formed by resin molding and fixed by adhesion. A focusing coil 103 having a Z axis as a winding axis and tracking coils 104 and 105 having an X axis as a winding axis are bonded and fixed to the lens holder 102. A balancer 106 for balancing the weight with the objective lens 101 is fixed to the lens holder 102. The objective lens 101, the objective lens holder 102, the focusing coil 103, the tracking coils 104 and 105, and the tolerancer 106 constitute a movable part.
[0006] 弾性支持部材 107は、薄い板バネ材で形成されている。この弾性支持部材 107は 、一端を対物レンズホルダ 102に固着され、他端をベース部材 109に固定された固 定部材 108に固着されている。この弾性支持部材 107が、可動部をフォーカシング 方向（Z軸方向）とトラッキング方向（Y軸方向）とに移動可能に支持する。  [0006] The elastic support member 107 is formed of a thin leaf spring material. The elastic support member 107 has one end fixed to the objective lens holder 102 and the other end fixed to a fixing member 108 fixed to the base member 109. This elastic support member 107 supports the movable part so as to be movable in the focusing direction (Z-axis direction) and the tracking direction (Y-axis direction).
[0007] 弾性支持部材 107は、通電性とパネ特性の両方に優れたリン青銅、ベリリウム銅な どの金属板をプレス加工で打ち抜き形成されており、フォーカシングコイル 103、トラ ッキングコイル 104、 105への通電も行う。  [0007] The elastic support member 107 is formed by stamping a metal plate such as phosphor bronze or beryllium copper, which is excellent in both current-carrying properties and panel characteristics. Also do.
[0008] ベース部材 109は、鉄など強磁性体の金属でできている。ベース部材 109によって 、フォーカシングコイル 103とトラッキングコイル 104、 105とを挟む。このベース部材 109は、互いに対向するヨーク 109a、 109bを具備し、ヨーク 109a、 109bのそれぞ れには磁束の方向が X軸方向であり、且つ、互いに対向する面の磁極が異なる 2個 のマグネット 110が接着固定され、磁気回路を構成する。  [0008] The base member 109 is made of a ferromagnetic metal such as iron. The base member 109 sandwiches the focusing coil 103 and the tracking coils 104 and 105. The base member 109 includes yokes 109a and 109b facing each other, and each of the yokes 109a and 109b has two magnetic flux directions in the X-axis direction and different magnetic poles on the surfaces facing each other. A magnet 110 is bonded and fixed to form a magnetic circuit.
[0009] 以上のように構成された従来の対物レンズ駆動装置について以下その動作につい て述べる。  The operation of the conventional objective lens driving apparatus configured as described above will be described below.
まず、フォーカシングコイル 103に電流が供給されると、このフォーカシングコイル 1 03に流れる電流と、磁気回路を構成するマグネット 110からの磁束とによって、フォ 一力シングコイル 103に Z軸方向の電磁駆動力が発生する。レンズホルダ 102を含 む可動部は弾性支持部材 107にて移動可能に支持されているので、この電磁駆動 力によって、可動部に固定された対物レンズ 101は光軸と平行なフォーカシング方向 に移動する。対物レンズをフォーカシング方向に移動させて、光ディスクに照射する レーザ光のフォーカシングの調整が行われる。  First, when a current is supplied to the focusing coil 103, an electromagnetic driving force in the Z-axis direction is applied to the forcing coil 103 by a current flowing through the focusing coil 103 and a magnetic flux from the magnet 110 constituting the magnetic circuit. Occurs. Since the movable part including the lens holder 102 is movably supported by the elastic support member 107, the objective lens 101 fixed to the movable part is moved in the focusing direction parallel to the optical axis by this electromagnetic driving force. . The objective lens is moved in the focusing direction to adjust the focusing of the laser beam that irradiates the optical disc.
[0010] また、図 12において、この対物レンズ駆動装置では、トラッキングコイル 104、 105 のそれぞれにつレ、て互いに反対方向に流れる電流を供給する。トラッキングコイル 1 04、 105の対物レンズ 101の光軸と平行な Z軸方向部分 104a、 105aを流れる電流 と、磁気回路を構成するマグネット 110からの磁束とによって、可動部をトラッキング 方向（Y軸方向）へと駆動する磁気駆動力 FYが発生する。レンズホルダ 102を含む 可動部は、弾性支持部材 107にて移動可能に支持されているので、この電磁駆動力 によって、可動部に固定された対物レンズ 101は光軸と直交するトラッキング方向に 移動する。対物レンズをトラッキング方向に移動させて、光ディスクに照射するレーザ 光のトラッキングの調整が行われる。 In FIG. 12, in this objective lens driving device, tracking coils 104 and 105 The currents flowing in the opposite directions to each other are supplied. The moving part is tracked in the tracking direction (Y-axis direction) by the current flowing through the Z-axis direction parts 104a and 105a parallel to the optical axis of the objective lens 101 of the tracking coils 104 and 105 and the magnetic flux from the magnet 110 constituting the magnetic circuit. ) Is generated. Since the movable part including the lens holder 102 is movably supported by the elastic support member 107, the objective lens 101 fixed to the movable part is moved in the tracking direction orthogonal to the optical axis by this electromagnetic driving force. . The objective lens is moved in the tracking direction to adjust the tracking of the laser beam irradiated onto the optical disk.
[0011] 一方、トラッキングコイル 104、 105の Y軸方向部分 104b、 105bを流れる電流と、 磁気回路を構成するマグネット 110力もの磁束とによって、トラッキングコイル 104、 1 05に Z軸方向の電磁駆動力 FZが発生する。しかし、これらの電磁駆動力 FZはブラ ス方向の力とマイナス方向の力の大きさが同じであり互いにキャンセルし合い合力は 0となり、可動部を Z軸方向へ駆動する力は発生しない。  [0011] On the other hand, the tracking coil 104, 105 has an electromagnetic driving force in the Z-axis direction due to the current flowing through the Y-axis direction parts 104b, 105b of the tracking coils 104, 105 and the magnetic flux of 110 magnets constituting the magnetic circuit. FZ occurs. However, these electromagnetic driving forces FZ have the same magnitude in the brass direction and in the minus direction, cancel each other, and the resultant force becomes 0, and no force is generated to drive the movable part in the Z-axis direction.
[0012] 可動部のフォーカシング方向乃至トラッキング方向への変位動作で XY平面に対す る可動部の傾き発生を防ぐためには、可動部の重心と、弾性支持部材 107の可動部 を支持する支持中心と、トラッキングコイル 104、 105で発生する駆動力の中心（駆動 中心）とは、変位動作する方向と直交する面内で各々一致させる必要がある。駆動中 心が支持中心とずれていると可動部を回転させるトルクが発生し、光ディスクに対し 対物レンズが傾斜し、情報記録面上の光スポットに収差が生じ、情報の再生信号が 劣化してしまう。  [0012] In order to prevent the movable portion from tilting with respect to the XY plane by the displacement operation of the movable portion in the focusing direction or the tracking direction, the center of gravity of the movable portion and the support center that supports the movable portion of the elastic support member 107 are provided. The center of the driving force generated by the tracking coils 104 and 105 (driving center) must be made to coincide with each other in a plane orthogonal to the direction of the displacement operation. When the driving center is deviated from the center of support, torque that rotates the moving part is generated, the objective lens tilts with respect to the optical disk, aberration occurs in the light spot on the information recording surface, and the information reproduction signal deteriorates. End up.
[0013] 一般に対物レンズ 101は可動部の光ディスク側（Z軸方向プラス側）に配置される。  In general, the objective lens 101 is disposed on the optical disc side (Z-axis direction plus side) of the movable part.
そのままでは可動部の重心及び弾性支持部材 107の支持中心は Z軸方向プラス側 となり、トラッキングコイル 104、 105の駆動中心とずれてしまう。そのため、黄銅など でできたバランサ 106をレンズホルダ 102の下側（Z軸方向マイナス側）に接着等の 方法で固着し、可動部の重心を下げることで、重心及び支持中心をトラッキング駆動 中心と一致させていた。  As it is, the center of gravity of the movable part and the support center of the elastic support member 107 are on the positive side in the Z-axis direction, and are shifted from the drive center of the tracking coils 104 and 105. For this reason, a balancer 106 made of brass or the like is fixed to the lower side (Z-axis direction minus side) of the lens holder 102 by bonding or the like, and the center of gravity and the support center are set as the tracking drive center by lowering the center of gravity of the movable part. Matched.
[0014] 特許文献 1 :特開平 11一 167737号公報  Patent Document 1: Japanese Patent Application Laid-Open No. 11-167737
発明の開示 発明が解決しょうとする課題 Disclosure of the invention Problems to be solved by the invention
[0015] しかし、上記従来の構成では、バランサを搭載しているため可動部の重量が大きく なる。このため、対物レンズ 101の移動加速度が不足し、光ディスクの面振れや偏心 に追従できなくなり、光ディスク上に記録された情報の再生信号が劣化するという問 題があった。  [0015] However, in the conventional configuration, since the balancer is mounted, the weight of the movable part is increased. For this reason, there has been a problem that the moving acceleration of the objective lens 101 is insufficient, and it becomes impossible to follow the surface deflection and eccentricity of the optical disc, and the reproduction signal of information recorded on the optical disc deteriorates.
[0016] また、バランサ 106を取り付けるスペースも必要となり、対物レンズ駆動装置の薄型 ィ匕が困難であるとレ、う問題があった。  [0016] In addition, a space for mounting the balancer 106 is required, and there is a problem that it is difficult to thin the objective lens driving device.
[0017] 本発明の目的は、上記従来の問題点を解決するものであり、バランサを用いないで[0017] An object of the present invention is to solve the above-mentioned conventional problems, and without using a balancer.
、再生信号の劣化が少なぐ且つ、薄型の対物レンズ駆動装置を提供することを目的 とする。 Another object of the present invention is to provide a thin objective lens driving device in which the reproduction signal is hardly deteriorated.
課題を解決するための手段  Means for solving the problem
[0018] 本発明に係る対物レンズ駆動装置は、光記録媒体に光学的に情報を記録または 再生するための対物レンズを駆動する対物レンズ駆動装置であって、 An objective lens driving device according to the present invention is an objective lens driving device that drives an objective lens for optically recording or reproducing information on an optical recording medium,
前記対物レンズを含む光学系が取り付けられたレンズホルダと、  A lens holder to which an optical system including the objective lens is attached;
一端が前記レンズホルダに取り付けられ、他端が固定部材に取り付けられ、前記レ ンズホルダを、前記光記録媒体の記録面に垂直なフォーカシング方向と、前記フォ 一力シング方向と垂直なトラッキング方向とのそれぞれの方向に対して移動可能に前 記固定部材について弾性支持する支持部材と、  One end is attached to the lens holder, and the other end is attached to a fixing member. The lens holder includes a focusing direction perpendicular to the recording surface of the optical recording medium and a tracking direction perpendicular to the forcing direction. A support member that elastically supports the fixing member so as to be movable in each direction;
前記フォーカシング方向と前記トラッキング方向とのそれぞれの方向に対して垂直 な方向に平行な卷回軸を有し、前記レンズホルダに固定された少なくとも一対の第 1 及び第 2のトラッキングコイルと、  At least a pair of first and second tracking coils having a winding axis parallel to a direction perpendicular to each of the focusing direction and the tracking direction, and fixed to the lens holder;
前記第 1及び第 2のトラッキングコイルに電磁力を発生させるように磁界を付与する マグネットと、  A magnet for applying a magnetic field so as to generate an electromagnetic force in the first and second tracking coils;
を備え、  With
前記第 1及び第 2のトラッキングコイルの駆動中心軸は、前記第 1及び第 2のトラツキ ングコイルの中心のそれぞれの卷回軸の中間に延在する軸として規定され、前記駆 動中心軸は、前記対物レンズ駆動装置の重心を通らなレ、と共に、  The drive center axes of the first and second tracking coils are defined as axes extending in the middle of the respective winding axes of the centers of the first and second tracking coils, and the drive center axes are Along with passing through the center of gravity of the objective lens driving device,
前記マグネットは、前記第 1及び第 2のトラッキングコイルに発生させる前記電磁力 によって生じるトルクの合計が 0となる着磁パターンを有することを特徴とする。 The magnet generates the electromagnetic force generated by the first and second tracking coils. It is characterized by having a magnetization pattern in which the total torque generated by is zero.
[0019] また、前記対物レンズ駆動装置の支持中心軸は、前記対物レンズ駆動装置の前記 重心を通ると共に、前記トラッキング方向と前記フォーカシング方向とを含む面に対し て垂直に延在する軸として規定できる。前記マグネットは、前記マグネットが対向する 前記第 1及び第 2のトラッキングコイルの各部分と前記支持中心軸との距離に応じた 着磁パターンを有するものであってもよい。  [0019] Further, the support central axis of the objective lens driving device is defined as an axis that passes through the center of gravity of the objective lens driving device and extends perpendicular to a plane including the tracking direction and the focusing direction. it can. The magnet may have a magnetization pattern corresponding to a distance between each portion of the first and second tracking coils facing the magnet and the support central axis.
[0020] さらに、前記マグネットは、前記トラッキング方向と前記フォーカシング方向とを含む 面内で、前記第 1及び第 2のトラッキングコイルの中心のそれぞれの卷回軸を結ぶ線 につレ、て非線対称の着磁パターンを有するものであってもよレ、。  [0020] Further, the magnet is non-linear with respect to a line connecting the winding axes of the centers of the first and second tracking coils in a plane including the tracking direction and the focusing direction. It may have a symmetrical magnetization pattern.
[0021] またさらに、前記マグネットは、前記トラッキング方向と前記フォーカシング方向とを 含む面内で、前記フォーカシング方向についてテーパ状の形状を有するものであつ てもよレ、。前記マグネットは、前記トラッキング方向と前記フォーカシング方向とを含む 面内で、前記フォーカシング方向について凸型形状を有するものであってもよい。  [0021] Still further, the magnet may have a tapered shape in the focusing direction within a plane including the tracking direction and the focusing direction. The magnet may have a convex shape in the focusing direction within a plane including the tracking direction and the focusing direction.
[0022] また、前記マグネットは、前記第 1のトラッキングコイルに電磁力を発生させる第 1マ グネットと、前記第 2のトラッキングコイルに電磁力を発生させる第 2マグネットとを備え てもよい。  [0022] The magnet may include a first magnet that generates an electromagnetic force in the first tracking coil and a second magnet that generates an electromagnetic force in the second tracking coil.
[0023] 前記マグネットは、前記第 1及び第 2のトラッキングコイルに対して、それぞれの卷回 軸に平行な磁束を作用させるものであってもよい。  [0023] The magnet may cause a magnetic flux parallel to each winding axis to act on the first and second tracking coils.
[0024] 前記マグネットは、前記トラッキング方向と前記フォーカシング方向とを含む面内で[0024] The magnet is within a plane including the tracking direction and the focusing direction.
、前記第 1及び第 2のトラッキングコイルの前記駆動中心軸と交差し、前記フォーカシ ング方向に平行な線について線対称の着磁パターンを有するものであってもよい。 The first and second tracking coils may have a line-symmetric magnetization pattern that intersects the drive center axis and is parallel to the focusing direction.
[0025] また、前記マグネットは、着磁部分と非着磁部分とを含む着磁パターンを有するも のであってもよい。 [0025] The magnet may have a magnetization pattern including a magnetized portion and a non-magnetized portion.
[0026] さらに、前記マグネットは、前記フォーカシング方向力 傾いた磁極の境界を有する [0026] Further, the magnet has a boundary of the magnetic pole inclined with the force in the focusing direction.
2極着磁の着磁パターンを有するものであってもよレ、。 It may have a magnetized pattern with two poles.
[0027] また、本発明に係る光学ヘッド装置は、前記対物レンズ駆動装置を備えたものとし てもよい。 [0027] Further, an optical head device according to the present invention may include the objective lens driving device.
[0028] さらに、本発明に係る光ディスク装置は、前記光学ヘッド装置を備えたものとしても よい。 Furthermore, the optical disk device according to the present invention may be provided with the optical head device. Good.
発明の効果  The invention's effect
[0029] 本発明の対物レンズ駆動装置は、トラッキングの駆動力中心と可動部重心、支持中 心の位置を一致させる必要がないので、可動部にバランサを付加する必要がない。 そこで、薄型でかつ高加速度を得ることが可能になり、薄型で、且つ、再生信号の劣 化が少なレ、光ディスク装置を提供できる。  [0029] The objective lens driving device of the present invention does not need to match the tracking driving force center with the position of the center of gravity of the movable part and the center of the support, and therefore it is not necessary to add a balancer to the movable part. Therefore, it is possible to provide an optical disc apparatus that is thin and capable of obtaining high acceleration, that is thin and that has little deterioration in reproduction signals.
図面の簡単な説明  Brief Description of Drawings
[0030] [図 1]本発明の実施の形態 1に係る対物レンズ駆動装置の構成を示す概略斜視図で ある。  FIG. 1 is a schematic perspective view showing a configuration of an objective lens driving device according to Embodiment 1 of the present invention.
[図 2]図 1の対物レンズ駆動装置のトラッキングコイルを含む面についての断面図で ある。  2 is a cross-sectional view of a surface including a tracking coil of the objective lens driving device in FIG.
[図 3]図 2のマグネットの形状を示す概略図である。  FIG. 3 is a schematic view showing the shape of the magnet of FIG.
[図 4]図 2のトラッキングコイルに発生する電磁駆動力の支持中心に対するトノレクを説 明する概略図である。  FIG. 4 is a schematic diagram for explaining the tonolec to the support center of the electromagnetic driving force generated in the tracking coil of FIG.
[図 5]本発明の実施の形態 1に係る別例の対物レンズ駆動装置の断面図である。  FIG. 5 is a cross-sectional view of another objective lens driving device according to Embodiment 1 of the present invention.
[図 6]本発明の実施の形態 2に係る対物レンズ駆動装置の構成を示す概略斜視図で ある。  FIG. 6 is a schematic perspective view showing a configuration of an objective lens driving device according to Embodiment 2 of the present invention.
[図 7]図 6の対物レンズ駆動装置の一つのトラッキングコイルを含む面についての断 面図である。  7 is a cross-sectional view of a surface including one tracking coil of the objective lens driving device of FIG.
[図 8]図 6の対物レンズ駆動装置のもう一つのトラッキングコイルを含む面についての 断面図である  FIG. 8 is a cross-sectional view of a surface including another tracking coil of the objective lens driving device of FIG.
[図 9]図 7のトラッキングマグネットの形状を示す概略図である。  FIG. 9 is a schematic view showing the shape of the tracking magnet of FIG.
[図 10]図 7及び図 8のトラッキングコイルに発生する電磁駆動力の支持中心に対する トルクを説明する概略図である。  FIG. 10 is a schematic diagram for explaining the torque with respect to the support center of the electromagnetic driving force generated in the tracking coil of FIGS. 7 and 8.
[図 11]従来の対物レンズ駆動装置の斜視図である。  FIG. 11 is a perspective view of a conventional objective lens driving device.
[図 12]図 11の対物レンズ駆動装置のトラッキングコイルを含む面についての断面図 である。  12 is a cross-sectional view of a surface including a tracking coil of the objective lens driving device in FIG.
符号の説明 [0031] 1、 21 対物レンズ Explanation of symbols [0031] 1, 21 Objective lens
2、 22 レンズホルダ  2, 22 Lens holder
3、 23、 24、 30、 31 フォーカシングコイル  3, 23, 24, 30, 31 Focusing coil
4、 5、 25、 26、 32、 33 トラッキングコィノレ  4, 5, 25, 26, 32, 33 Tracking coin
7、 27 弾性支持部材  7, 27 Elastic support member
8、 28 固定部材  8, 28 Fixing member
9、 29 ベース部材  9, 29 Base material
10 マグネット  10 Magnet
101 対物レンズ  101 Objective lens
102 レンズホルダ  102 Lens holder
103 フォーカシングコイル  103 Focusing coil
104、 105 トラッキングコィノレ  104, 105 Tracking coin
106 バランサ  106 Balancer
107 弾性部材  107 Elastic member
108 固定部材  108 Fixing member
109 ベース部材  109 Base material
110 マグネット  110 magnet
発明を実施するための最良の形態  BEST MODE FOR CARRYING OUT THE INVENTION
[0032] 本発明の実施の形態に係る対物レンズ駆動装置について、添付図面を用いて説 明する。なお、図面において実質的に同一の部材には同一の符号を付している。  [0032] An objective lens driving device according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the drawings, substantially the same members are denoted by the same reference numerals.
[0033] (実施の形態 1)  [Embodiment 1]
本発明の実施の形態 1に係る対物レンズ駆動装置について、図 1及び図 2を用いて 説明する。図 1は、本発明の実施の形態 1に係る対物レンズ駆動装置の構成を示す 概略斜視図である。図 2は、図 1の対物レンズ駆動装置の一対のトラッキングコイル 4 、 5を含む面についての断面図である。図 1及び図 2において、ガラスプレス又は樹脂 成形により形成された対物レンズ 1がレンズホルダ 2に接着により固定されている。レ ンズホルダ 2は樹脂成形により形成されている。レンズホルダ 2には、 Z軸方向を卷回 軸とするフォーカシングコイル 3と、 X軸方向を卷回軸とする 2つのトラッキングコイル 4 、 5が接着固定されている。対物レンズ 1、対物レンズホルダ 2、フォーカシングコィノレ 3、トラッキングコイル 4、 5により、可動部が構成される。 An objective lens driving apparatus according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a schematic perspective view showing the configuration of the objective lens driving device according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of a surface including the pair of tracking coils 4 and 5 of the objective lens driving device of FIG. 1 and 2, an objective lens 1 formed by glass press or resin molding is fixed to a lens holder 2 by adhesion. The lens holder 2 is formed by resin molding. The lens holder 2 includes a focusing coil 3 with the Z-axis direction as the winding axis and two tracking coils 4 with the X-axis direction as the winding axis. , 5 is glued and fixed. The objective lens 1, the objective lens holder 2, the focusing coinlet 3, and the tracking coils 4 and 5 constitute a movable part.
[0034] 弾性支持部材 7は、薄レ、板バネ材で形成されてレ、る。弾性支持部材 7は、一端を対 物レンズホルダ 2に固着され、他端をベース部材 9に固定された固定部材 8に固着さ れている。この弾性支持部材 7によって、可動部をフォーカシング方向（Z軸方向）とト ラッキング方向 (Y軸方向）とに移動可能に支持する。  [0034] The elastic support member 7 is formed of a thin, leaf spring material. The elastic support member 7 has one end fixed to the object lens holder 2 and the other end fixed to a fixing member 8 fixed to the base member 9. The elastic support member 7 supports the movable part so as to be movable in the focusing direction (Z-axis direction) and the tracking direction (Y-axis direction).
[0035] 弾性支持部材 7は、通電性とパネ特性の両方に優れたリン青銅、ベリリウム銅など の金属板をプレス加工で打ち抜き形成されている。この弾性支持部材 7は、一端をフ オーカシングコイル 3及びトラッキングコイル 4、 5と半田付けにより結合されており、通 電ができるように構成されてレ、る。  [0035] The elastic support member 7 is formed by stamping a metal plate such as phosphor bronze or beryllium copper, which is excellent in both conductivity and panel characteristics. One end of the elastic support member 7 is connected to the focusing coil 3 and the tracking coils 4 and 5 by soldering, and is configured to be electrically connected.
[0036] ベース部材 9は、鉄など強磁性体の金属でできている。ベース部材 9は、フォーカシ ングコイル 3とトラッキングコイル 4、 5とを挟み、互いに対向するヨーク 9a、 9bを具備 する。ヨーク 9a、 9bには、磁束の方向が X軸方向であり、且つ、対向する面の磁極が 異なる 2個のマグネット 10が接着固定され、磁気回路を構成する。  [0036] The base member 9 is made of a ferromagnetic metal such as iron. The base member 9 includes yokes 9a and 9b facing each other with the focusing coil 3 and the tracking coils 4 and 5 sandwiched therebetween. To the yokes 9a and 9b, two magnets 10 having a magnetic flux direction in the X-axis direction and different magnetic poles on the opposing surfaces are bonded and fixed to constitute a magnetic circuit.
[0037] 以上のように構成された対物レンズ駆動装置について、以下にその動作を述べる。  The operation of the objective lens driving apparatus configured as described above will be described below.
フォーカシングコイル 3に電流が供給されると、フォーカシングコイル 3に流れる電流 と、磁気回路を構成するマグネット 10からの X軸方向の磁束とによって、フォーカシン グコイル 3に可動部をフォーカシング方向へと駆動する電磁駆動力を発生する。レン ズホルダ 2を含む可動部は弾性支持部材 7にて移動可能に支持されているので、こ の電磁駆動力によって、可動部に固定された対物レンズ 1は光軸と平行なフォーカシ ング方向に移動する。対物レンズ 1をフォーカシング方向に移動させて、光ディスクに 照射するレーザ光のフォーカシングの調整が行われる。  When the current is supplied to the focusing coil 3, the movable part is driven in the focusing direction by the current flowing in the focusing coil 3 and the magnetic flux in the X-axis direction from the magnet 10 constituting the magnetic circuit. Generate electromagnetic driving force. Since the movable part including the lens holder 2 is movably supported by the elastic support member 7, the objective lens 1 fixed to the movable part is moved in the focusing direction parallel to the optical axis by this electromagnetic driving force. To do. The objective lens 1 is moved in the focusing direction to adjust the focusing of the laser beam irradiated on the optical disk.
[0038] また、トラッキングコイル 4、 5に電流が供給されると、トラッキングコイル 4、 5の対物 レンズ 1の光軸と平行な Z軸方向部分 4a、 5aを流れる電流と、磁気回路を構成する マグネット 10からの X軸方向の磁束とによって、可動部をトラッキング方向（Y軸方向） へと駆動する磁気駆動力 FYを発生する。レンズホルダ 2を含む可動部は、弾性支持 部材 7にて移動可能に支持されているので、この電磁駆動力によって、可動部に固 定された対物レンズ 1は光軸と直交するトラッキング方向に移動する。対物レンズ 1を トラッキング方向に移動させて、光ディスクに照射するレーザ光のトラッキングの調整 が行われる。 [0038] When a current is supplied to the tracking coils 4 and 5, the current flowing through the Z-axis direction parts 4a and 5a parallel to the optical axis of the objective lens 1 of the tracking coils 4 and 5 constitutes a magnetic circuit. The magnetic driving force FY that drives the movable part in the tracking direction (Y-axis direction) is generated by the magnetic flux in the X-axis direction from the magnet 10. Since the movable part including the lens holder 2 is movably supported by the elastic support member 7, the objective lens 1 fixed to the movable part is moved in the tracking direction orthogonal to the optical axis by this electromagnetic driving force. To do. Objective lens 1 The tracking of the laser beam irradiated to the optical disc is adjusted by moving in the tracking direction.
[0039] なお、トラッキングコイル 4、 5の駆動中心軸は、トラッキングコイル 4、 5の中心のそ れぞれの卷回軸の中間に延在する軸として規定される。駆動中心は、フォーカシング 方向（Z軸方向）とトラッキング方向（Y軸方向）とを含む面と駆動中心軸とが交差する 点として規定される。すなわち、トラッキングコイル 4、 5を含む面と駆動中心軸とが交 差する点として規定される。  It should be noted that the drive center axis of the tracking coils 4 and 5 is defined as an axis extending in the middle of each winding axis at the center of the tracking coils 4 and 5. The drive center is defined as the point where the drive center axis intersects the plane including the focusing direction (Z-axis direction) and the tracking direction (Y-axis direction). That is, it is defined as the point where the plane including the tracking coils 4 and 5 intersects with the drive center axis.
[0040] 次に、本発明の実施の形態 1に係る対物レンズ駆動装置の特徴について説明する 図 1に示すように、実施の形態 1に係る対物レンズ駆動装置では、バランサを設けて いない。バランサを設けていないので、図 2に示すように、可動部の重心及び弾性支 持部材 7の可動部を支持する支持中心 Gの Z軸方向位置は、トラッキングコイル 4、 5 の対物レンズ 1の光軸と平行な Z軸方向部分 4a、 5aの中心位置（駆動中心）よりも Z 軸方向プラス側に位置している。すなわち、対物レンズ駆動装置の支持中心とトラッ キングコイル 4、 5の駆動中心とは外れている。上述したように、対物レンズ駆動装置 の支持中心がトラッキングコイル 4、 5の駆動中心と外れている場合、トラッキングコィ ル 4、 5に生じる Y軸方向の電磁駆動力 FYによる支持中心について反時計回りのト ルク TZaが発生する（図 2)。このトルク TZaは、可動部を X軸について回転させ、対 物レンズ 1の光軸を傾かせる原因となる。  Next, features of the objective lens driving device according to Embodiment 1 of the present invention will be described. As shown in FIG. 1, the objective lens driving device according to Embodiment 1 is not provided with a balancer. Since no balancer is provided, as shown in FIG. 2, the center of gravity of the movable part and the position of the support center G that supports the movable part of the elastic support member 7 are in the Z-axis direction of the objective lens 1 of the tracking coils 4 and 5. It is located on the positive side in the Z-axis direction from the center position (drive center) of the Z-axis direction parts 4a and 5a parallel to the optical axis. That is, the support center of the objective lens driving device and the driving center of the tracking coils 4 and 5 are deviated. As described above, when the support center of the objective lens drive device is out of the drive center of the tracking coils 4 and 5, the support center by the electromagnetic driving force FY in the Y-axis generated in the tracking coils 4 and 5 is counterclockwise. Torque TZa is generated (Fig. 2). This torque TZa causes the movable part to rotate about the X axis and causes the optical axis of the object lens 1 to tilt.
[0041] 一方、トラッキングコイル 4、 5によって発生する電磁駆動力には、 Z軸方向の部分 4 a、 5aによるトラッキング方向（Y軸方向）の電磁駆動力 FYの他に、磁束が作用する Y 軸方向の部分 4b、 4c、 5b、 5c等によって生じる Z軸方向の電磁駆動力 FZがある。こ の Z軸方向の電磁駆動力 FZについても支持中心周りのトルク TZbが発生する。そこ で、本発明者は、 Y軸方向の部分によって発生する Z軸方向の電磁駆動力 FZを制 御することによって、 Y軸方向の電磁駆動力 FYによるトノレク TZaを時計回りのトルク T Zbによって相殺して、全体の合計トルクを 0とすることに思い至った。  [0041] On the other hand, the electromagnetic driving force generated by the tracking coils 4 and 5 is affected by magnetic flux in addition to the electromagnetic driving force FY in the tracking direction (Y-axis direction) by the portions 4a and 5a in the Z-axis direction. There is an electromagnetic driving force FZ in the Z-axis direction generated by the axial parts 4b, 4c, 5b, 5c, etc. The torque TZb around the support center is also generated for this electromagnetic driving force FZ in the Z-axis direction. Therefore, the present inventor controls the electromagnetic driving force FZ in the Z-axis direction generated by the portion in the Y-axis direction, so that the Tonlek TZa by the electromagnetic driving force FY in the Y-axis is rotated by the clockwise torque T Zb. I came up with the idea of offsetting the total torque to 0.
[0042] 本発明者は、図 3に示すような逆台形形状のマグネット 10を用いて、トラッキングコ ィノレ 4、 5の Y軸方向の部分 4b、 4c、 5b、 5cに生じる電磁駆動力を制御することを考 えた。この対物レンズ駆動装置では、ヨーク 9a、 9b及びマグネット 10は、 Z軸方向の 下底より上底の寸法が大きい逆台形断面形状としている。電磁駆動力の大きさは磁 束の作用する部分の長さに比例して大きくなる。すなわち、トラッキングコイル 4、 5に 生じる電磁駆動力は、マグネット 10による磁束の作用する部分の長さによって大きさ が変わる。そこで、マグネット 10の形状を上辺が長く下辺が短い台形形状とすること によって、トラッキングコイル 4、 5の Y軸方向の部分 4b、 4c、 5b、及び 5cの磁束の作 用する長さを制御できる。トラッキングコイル 4、 5の Y軸方向の部分 4b、 4c、 5b、及 び 5cに生じる電磁駆動力を制御することによって、時計回りのトノレク TZbを発生させ 、 Y軸方向の電磁駆動力 FYによるトルク TZaを相殺して、全体の合計トルクを 0とす ること力 Sできる。 [0042] The present inventor uses the inverted trapezoidal magnet 10 as shown in Fig. 3 to control the electromagnetic driving force generated in the Y axis direction portions 4b, 4c, 5b, 5c of the tracking coins 4, 5 Think to do Yeah. In this objective lens driving device, the yokes 9a and 9b and the magnet 10 have an inverted trapezoidal cross-sectional shape in which the dimension of the upper base is larger than the lower base in the Z-axis direction. The magnitude of the electromagnetic driving force increases in proportion to the length of the part where the magnetic flux acts. That is, the magnitude of the electromagnetic driving force generated in the tracking coils 4 and 5 varies depending on the length of the portion where the magnetic flux acts by the magnet 10. Therefore, by making the shape of the magnet 10 a trapezoidal shape with a long upper side and a short lower side, the length of the magnetic flux applied to the portions 4b, 4c, 5b and 5c in the Y-axis direction of the tracking coils 4 and 5 can be controlled. . By controlling the electromagnetic driving force generated in the Y-axis direction parts 4b, 4c, 5b, and 5c of the tracking coils 4 and 5, a clockwise tonlek TZb is generated and the Y-axis electromagnetic driving force FY torque Force S to offset TZa and make the total torque of the whole zero.
[0043] 図 4は、図 2の一対のトラッキングコイル 4、 5に生じる電磁駆動力と、この電磁駆動 力による支持中心 Gに対するトルクを説明する概略図である。図 4では、トラッキング コイル 4、 5を点線で示している。図 3のマグネットによる磁束の作用するトラッキングコ ィル 4、 5の各部分に生じる電磁駆動力を矢印で示している。また、支持中心から電 磁駆動力の作用点までを実線で示してレ、る。  FIG. 4 is a schematic diagram for explaining the electromagnetic driving force generated in the pair of tracking coils 4 and 5 in FIG. 2 and the torque with respect to the support center G by this electromagnetic driving force. In FIG. 4, the tracking coils 4 and 5 are indicated by dotted lines. The electromagnetic drive force generated in each part of the tracking coils 4 and 5 where the magnetic flux acts by the magnet in Fig. 3 is indicated by arrows. The solid line from the support center to the point of action of the electromagnetic driving force is shown.
[0044] 上述のように、可動部の重心と弾性支持部材 7の可動部を支持する支持中心 Gと、 トラッキングコイル 4、 5の対物レンズ 1の光軸と平行な Z軸方向部分 4a、 5aの中心位 置（駆動中心）とは Z軸方向にずれがある。そのため、トラッキングコイル 4、 5の Z軸方 向部分 4a、 5aに発生する電磁駆動力 FY1、 FY2によって支持中心 Gについて反時 計回りのトノレク TZaが発生する。  [0044] As described above, the center of gravity of the movable part, the support center G that supports the movable part of the elastic support member 7, and the Z-axis direction parts 4a, 5a parallel to the optical axis of the objective lens 1 of the tracking coils 4, 5 There is a deviation in the Z-axis direction from the center position (drive center). Therefore, the counterclockwise tonnolek TZa is generated about the support center G by the electromagnetic driving forces FY1 and FY2 generated in the Z-axis direction parts 4a and 5a of the tracking coils 4 and 5.
[0045] 一方、トラッキングコィノレ 4、 5の Y軸方向咅分 4b、 4c、 5b、 5cにもマグネット 10力ら の磁束が作用する。トラッキングコイル 4、 5に電流が供給されることにより、 Y軸方向 の部分 4b、 4c、 5b、 5cに Z軸方向の電磁駆動力 FZ1、 FZ2、 FZ3、 FZ4が発生する 。支持中心 Gと駆動中心とは Z軸方向にずれがあるので、 Z軸方向の電磁駆動力に ついてもトルクが発生する。このトルクは支持中心 Gからの距離ベクトルと力のベタト ルとのべクトノレ積として表される。  On the other hand, a magnetic flux of 10 magnets also acts on the apportionments 4b, 4c, 5b and 5c in the Y-axis direction of the tracking coinlets 4 and 5. When current is supplied to the tracking coils 4 and 5, electromagnetic driving forces FZ1, FZ2, FZ3, and FZ4 in the Z axis direction are generated in the Y axis direction parts 4b, 4c, 5b, and 5c. Since the support center G and the drive center are misaligned in the Z-axis direction, torque is also generated for the electromagnetic drive force in the Z-axis direction. This torque is expressed as the vector product of the distance vector from the support center G and the force vector.
[0046] この対物レンズ駆動装置では、マグネット 10は、図 3に示すように、トラッキング方向 及びフォーカシング方向を含む面内の形状を逆台形形状としている。電磁駆動力は 、磁束の作用する長さに比例して大きくなる。マグネット 10の形状を制御することで、 部分 4b、 5bは、部分 4c、 5cより長くなる。そのため、部分 4b、 5bに生じる電磁駆動 力 FZ1、 FZ3は、部分 4c、 5cに生じる電磁駆動力 FZ2、 FZ4よりも大きい。一方、支 持中心 Gは、駆動中心よりも Z軸方向のプラス側に外れているので、部分 4b、 5bは、 部分 4c、 5cより支持中心 Gから近い。 In this objective lens driving device, the magnet 10 has an inverted trapezoidal shape in the plane including the tracking direction and the focusing direction, as shown in FIG. Electromagnetic driving force is , And increases in proportion to the length of magnetic flux. By controlling the shape of the magnet 10, the parts 4b and 5b are longer than the parts 4c and 5c. Therefore, the electromagnetic driving forces FZ1 and FZ3 generated in the parts 4b and 5b are larger than the electromagnetic driving forces FZ2 and FZ4 generated in the parts 4c and 5c. On the other hand, since the support center G is off the plus side in the Z-axis direction from the drive center, the parts 4b and 5b are closer to the support center G than the parts 4c and 5c.
[0047] そこで、支持中心 Gからの距離に応じてマグネットの形状を制御して、部分 4b、 4c、 5b、 5cの長さを制御する。部分 4b、 4c、 5b、 5cの長さによって、 Z軸方向の電磁駆 動力 FZ1、 FZ2、 FZ3、 FZ4の大きさを制御する。 Z軸方向の電磁駆動力 FZ1、 FZ2 、 FZ3、 FZ4によるトルクの和をトルク TZbとする。このトルク TZbは、トラッキングコィ ル 4、 5の Z軸方向部分 4a、 5aによって発生する反時計回りのトルク TZaとは逆向き、 すなわち、支持中心 Gに対し X軸周りに時計回りの向きを有するようにする。また、 Y 軸方向の部分 4b、 4c、 5b、及び 5cによる時計回りのトルク TZbの大きさを、 Z軸方向 部分 4a、 5aによる反時計回りのトルク TZaと同じ大きさになるように制御する。これに より、 2つの反対方向のトルク TZaとトルク TZbとは互いにキャンセルし合って略 0とす ること力 Sできる。そこで可動部の回転による対物レンズ 1の傾きを抑えることができる。  [0047] Therefore, the length of the portions 4b, 4c, 5b, 5c is controlled by controlling the shape of the magnet according to the distance from the support center G. The size of the electromagnetic drive FZ1, FZ2, FZ3, FZ4 in the Z-axis direction is controlled by the length of the parts 4b, 4c, 5b, 5c. The sum of the torque generated by the electromagnetic driving forces FZ1, FZ2, FZ3, and FZ4 in the Z-axis direction is defined as torque TZb. This torque TZb has the opposite direction to the counterclockwise torque TZa generated by the Z-axis direction parts 4a and 5a of the tracking coils 4 and 5, that is, the clockwise direction around the X axis with respect to the support center G. Like that. Also, the magnitude of the clockwise torque TZb by the Y-axis direction parts 4b, 4c, 5b, and 5c is controlled to be the same magnitude as the counterclockwise torque TZa by the Z-axis direction parts 4a, 5a. . As a result, the torques TZa and TZb in the two opposite directions cancel each other and can be reduced to substantially zero. Therefore, the inclination of the objective lens 1 due to the rotation of the movable part can be suppressed.
[0048] なお、この対物レンズ駆動装置において、トラッキングコイル 4、 5に生じる電磁駆動 力の合力は、トラッキング方向である Y軸方向の合力のみとし、 Z軸方向の合力は 0と する必要がある。そこで、それぞれの方向の合力について検討する。トラッキング方 向である Y軸方向には上述のように（FY1 + FY2)の電磁駆動力が生じる。一方、マ グネット 10は、 YZ面内で Z軸方向に平行な線について線対称の形状、すなわち線 対称の着磁パターンとしてレ、る。マグネット 10の形状を YZ平面で Z軸に線対称とする ことで、 Y軸方向の部分 4bと部分 5bの長さを同一とし、部分 4cと部分 5cの長さを同 一としている。そこで、部分 4bに生じる電磁駆動力 FZ1は、部分 5bに生じる電磁駆 動力 FZ3に対して逆向きで同じ大きさとなる。また、部分 4cに生じる電磁駆動力 FZ2 は、部分 5cに生じる電磁駆動力 FZ4に対して逆向きで同じ大きさとなる。そこで、 Z軸 方向の電磁駆動力の合力は 0となる。トラッキングコイル 4、 5に生じる電磁駆動力の 合力は、トラッキング方向である Y軸方向のみとなる。  [0048] In this objective lens driving device, the resultant force of the electromagnetic driving force generated in the tracking coils 4 and 5 must be only the resultant force in the Y-axis direction, which is the tracking direction, and the resultant force in the Z-axis direction must be 0. . Therefore, consider the resultant force in each direction. In the Y-axis direction, which is the tracking direction, an electromagnetic drive force of (FY1 + FY2) is generated as described above. On the other hand, the magnet 10 has a line-symmetric shape with respect to a line parallel to the Z-axis direction in the YZ plane, that is, a line-symmetric magnetization pattern. By making the shape of the magnet 10 line-symmetric with respect to the Z axis on the YZ plane, the lengths of the parts 4b and 5b in the Y axis direction are made the same, and the lengths of the parts 4c and 5c are made the same. Therefore, the electromagnetic driving force FZ1 generated in the part 4b is the same in the opposite direction to the electromagnetic driving force FZ3 generated in the part 5b. Further, the electromagnetic driving force FZ2 generated in the portion 4c is the same in the opposite direction to the electromagnetic driving force FZ4 generated in the portion 5c. Therefore, the resultant force of electromagnetic driving force in the Z-axis direction is zero. The resultant electromagnetic drive force generated in the tracking coils 4 and 5 is only in the Y-axis direction, which is the tracking direction.
[0049] 以上のように、実施の形態 1に係る対物レンズ駆動装置によれば、マグネット 10の 断面を逆台形形状としている。マグネット 10の形状は、支持中心 Gからの距離を考慮 して制御する。マグネット 10の形状によって、トラッキングコイル 4、 5の Y軸方向の部 分 4b、 4c、 5b、 5cの長さを制御する。部分 4b、 4c、 5b、 5cの長さによって Z軸方向 の電磁駆動力 FZを制御する。この Z軸方向の電磁駆動力 FZによるトノレク TZbの向き を Y軸方向の電磁駆動力 FYによるトノレク TZaと反対向きとすると共に、同じ大きさに 制御することによって、支持中心 Gの周りのトルク合計を 0とすることができる。これに よって、トラッキング駆動時に発生する対物レンズ 1の傾きを抑制でき、光ディスクの 情報再生性能に優れた対物レンズ駆動装置を提供できる。 As described above, according to the objective lens driving device according to the first embodiment, the magnet 10 The cross section has an inverted trapezoidal shape. The shape of the magnet 10 is controlled in consideration of the distance from the support center G. Depending on the shape of the magnet 10, the lengths of the tracking coils 4, 5 in the Y-axis direction 4b, 4c, 5b, 5c are controlled. The electromagnetic driving force FZ in the Z-axis direction is controlled by the length of the parts 4b, 4c, 5b, and 5c. The total torque around the support center G is controlled by making the direction of Tonlek TZb by the electromagnetic driving force FZ in the Z-axis opposite to that of Tonlek TZa by the Y-axis electromagnetic driving force FY and controlling it to the same magnitude. Can be set to 0. This can suppress the tilt of the objective lens 1 that occurs during tracking driving, and can provide an objective lens driving device that excels in information reproduction performance of the optical disc.
[0050] なお、本実施の形態 1ではマグネット 10の X軸方向の断面を台形形状とした力 図 5に示すように、 X軸方向の断面を逆凸型としてもよい。この場合も同様に、トラツキン グコィノレ 4、 5の Y軸方向部分 4b、 4c、 5b、 5cの磁束の作用する長さを制御でき、支 持中心について時計回りのトノレク TZbを発生させることができるので同等の効果が得 られる。 In the first embodiment, the force in which the cross section in the X-axis direction of the magnet 10 has a trapezoidal shape may be a reverse convex shape as shown in FIG. In this case as well, the length of the magnetic flux acting on the Y-axis direction parts 4b, 4c, 5b, and 5c of the tracking coils 4 and 5 can be controlled, and the clockwise tonlect TZb can be generated about the support center. The same effect can be obtained.
[0051] なお、本実施の形態 1ではトラッキングコイル 4、 5の形状は、略長方形であるが、こ れに限られず、円形、長円形であっても同等の効果が得られる。  [0051] In the first embodiment, the shape of the tracking coils 4 and 5 is substantially rectangular. However, the shape is not limited to this, and the same effect can be obtained even if the shape is circular or oval.
[0052] (実施の形態 2)  [0052] (Embodiment 2)
実施の形態 2に係る対物レンズ駆動装置について説明する。図 6は、本発明の実 施の形態 2に係る対物レンズ駆動装置の構成を示す概略斜視図である。図 7は、トラ ッキングコイル 25を含む面を示す断面図である。図 8は、トラッキングコイル 26を含む 面を示す断面図である。この対物レンズ駆動装置では、実施の形態 1に係る対物レ ンズ駆動装置と比較すると、フォーカシングコイル 23、 24は、トラッキングコイル 25、 2 6と同様に X軸方向の卷回軸を有する点で相違する。また、この対物レンズ駆動装置 は、実施の形態 1に係る対物レンズ駆動装置と比較すると、 2つのトラッキングコイル 2 5、 26をレンズホルダ 22の同一の面ではなぐ相対する面に設けている点で相違す る。さらに、それぞれのトラッキングコイル 25、 26に磁束を作用させるトラッキングマグ ネット 32、 33をそれぞれ別個のマグネットとして設けている点で相違する。実施の形 態 2に係る対物レンズ駆動装置では、トラッキングマグネット 32、 33は、 ZX平面から Y 軸方向に傾いた面 32a、 33aについて磁極が反転した着磁パターンを有することを 特徴とする。 An objective lens driving apparatus according to Embodiment 2 will be described. FIG. 6 is a schematic perspective view showing the configuration of the objective lens driving device according to Embodiment 2 of the present invention. FIG. 7 is a cross-sectional view showing a surface including the tracking coil 25. FIG. 8 is a cross-sectional view showing a surface including the tracking coil 26. Compared with the objective lens driving device according to the first embodiment, this objective lens driving device is different in that the focusing coils 23 and 24 have a winding axis in the X-axis direction like the tracking coils 25 and 26. To do. Further, this objective lens driving device is different from the objective lens driving device according to Embodiment 1 in that the two tracking coils 25 and 26 are provided on opposite surfaces of the lens holder 22 on the same surface. No. Another difference is that tracking magnets 32 and 33 for applying magnetic flux to the tracking coils 25 and 26 are provided as separate magnets. In the objective lens driving device according to Embodiment 2, the tracking magnets 32 and 33 have a magnetization pattern in which the magnetic poles are reversed on the surfaces 32a and 33a inclined in the Y-axis direction from the ZX plane. Features.
[0053] 次に、この対物レンズ駆動装置の各構成部材について説明する。  Next, each component of the objective lens driving device will be described.
ガラスプレス又は樹脂成形により形成された対物レンズ 21がレンズホルダ 22に接 着により固定されている。レンズホルダ 22は、樹脂成形により形成されており、 X軸方 ^を卷回軸とするフォーカシングコイル 23、 24と、 X軸方向を卷回軸とするトラツキン グコィノレ 25、 26とが接着固定されている。レンズホルダ 22の X軸方向に垂直な 2つ の面のうち、一方の面にフォーカシングコイル 23とトラッキングコイル 25とを備え、他 方の面にフォーカシングコイル 24とトラッキングコイル 26とを備える。対物レンズ 21、 対物レンズホルダ 22、フォーカシングコイル 23、 24、トラッキングコイル 25、 26によつ て可動部が構成される。  An objective lens 21 formed by glass press or resin molding is fixed to the lens holder 22 by adhesion. The lens holder 22 is formed by resin molding, and focusing coils 23 and 24 having a winding axis in the X-axis direction ^ and tracking coinoles 25 and 26 having a winding axis in the X-axis direction are bonded and fixed. Yes. Of the two surfaces perpendicular to the X-axis direction of the lens holder 22, a focusing coil 23 and a tracking coil 25 are provided on one surface, and a focusing coil 24 and a tracking coil 26 are provided on the other surface. The objective lens 21, the objective lens holder 22, the focusing coils 23 and 24, and the tracking coils 25 and 26 constitute a movable part.
[0054] 弾性支持部材 27は、薄い板バネ材で形成されている。この弾性支持部材 27は、一 端を対物レンズホルダ 22に固着され、他端をベース部材 29に固定された固定部材 2 8に固着されている。この弾性支持部材 27によって、可動部をフォーカシング方向（Z 軸方向）とトラッキング方向（Y軸方向）とに移動可能に支持する。  [0054] The elastic support member 27 is formed of a thin leaf spring material. The elastic support member 27 has one end fixed to the objective lens holder 22 and the other end fixed to a fixing member 28 fixed to the base member 29. The elastic support member 27 supports the movable part so as to be movable in the focusing direction (Z-axis direction) and the tracking direction (Y-axis direction).
[0055] 弾性支持部材 27は、通電性とパネ特性の両方に優れたリン青銅、ベリリウム銅など の金属板をプレス加工で打ち抜き形成されている。弾性支持部材 27は、一端をフォ 一力シングコイル 23、 24、トラッキングコイル 25、 26と半田付けにより結合されており 、通電ができるように構成されている。  [0055] The elastic support member 27 is formed by stamping a metal plate such as phosphor bronze or beryllium copper, which is excellent in both conductivity and panel characteristics, by pressing. One end of the elastic support member 27 is connected to the forcing coils 23 and 24 and the tracking coils 25 and 26 by soldering, and is configured to be energized.
[0056] ベース部材 29は、鉄などの強磁性体金属でできている。このベース部材 29は、フ オーカシングコイル 23、 24とトラッキングコィノレ 25、 26と対向する位置にそれぞれョ ーク 29a、 29bを具備している。ヨーク 29aには、フォーカシングコイル 23とトラツキン グコイル 25のそれぞれに対向した面にフォーカシングマグネット 30とトラッキングマグ ネット 32とが接着固定されている。ヨーク 29bには、フォーカシングコイル 24とトラツキ ングコイル 26のそれぞれに対向した面にフォーカシングマグネット 31とトラッキングマ グネット 33とが接着固定されている。トラッキングマグネット 32、 33は、図 9に示すよう に、 ZX平面力、ら Y軸方向に傾いた面 32a、 33aについて磁極が反転した着磁パター ンを有する。なお、図 9では、磁極として N極、 S極を示した力 着磁パターンを上記 の場合に限定するものではなレ、。着磁パターンは電流の向きに応じて適宜変更して あよい。 [0056] The base member 29 is made of a ferromagnetic metal such as iron. The base member 29 is provided with yokes 29a and 29b at positions facing the focusing coils 23 and 24 and the tracking coins 25 and 26, respectively. A focusing magnet 30 and a tracking magnet 32 are bonded and fixed to the yoke 29a on surfaces facing the focusing coil 23 and the tracking coil 25, respectively. A focusing magnet 31 and a tracking magnet 33 are bonded and fixed to the yoke 29b on the surfaces facing the focusing coil 24 and the tracking coil 26, respectively. As shown in FIG. 9, the tracking magnets 32 and 33 have a magnetization pattern in which the magnetic poles are reversed with respect to the surfaces 32a and 33a inclined in the Y-axis direction from the ZX plane force. In FIG. 9, the force magnetization pattern showing N pole and S pole as magnetic poles is not limited to the above case. Change the magnetization pattern appropriately according to the direction of current. Good.
[0057] この対物レンズ駆動装置では、一対のフォーカシングコイルとトラッキングコイルで 構成される 2つの駆動系を有する。第 1の駆動系は、フォーカシングコイル 23と、フォ 一力シングマグネット 30と、トラッキングコイル 25と、トラッキングマグネット 32とで構成 される。また、第 2の駆動系は、フォーカシングコイル 24と、フォーカシングマグネット 31と、トラッキングコイル 26と、トラッキングマグネット 33とで構成される。第 1の駆動系 と第 2の駆動系とは、対物レンズ 21の光軸 (Z軸）周りに 180度対称に配置されている  [0057] This objective lens driving device has two driving systems each composed of a pair of focusing coils and tracking coils. The first drive system includes a focusing coil 23, a forcing single magnet 30, a tracking coil 25, and a tracking magnet 32. The second drive system includes a focusing coil 24, a focusing magnet 31, a tracking coil 26, and a tracking magnet 33. The first drive system and the second drive system are arranged symmetrically around the optical axis (Z axis) of the objective lens 21 by 180 degrees.
[0058] 以上のように構成された対物レンズ駆動装置について、以下にその動作を述べる。 The operation of the objective lens driving device configured as described above will be described below.
図 7は、図 6の対物レンズ駆動装置のフォーカシングコイル 23とトラッキングコイル 2 5とを含む面について、 X軸方向のプラス側から見た断面図である。図 7では、可動部 を実線で示し、フォーカシングマグネット 30と、トラッキングマグネット 32と、ヨーク 29a とを破線で示す。図 8は、図 6の対物レンズ駆動装置のフォーカシングコイル 24とトラ ッキングコイル 26とを含む面について、 X軸方向のマイナス側から見た断面図である 。図 8では、可動部を実線で示し、フォーカシングマグネット 31と、トラッキングマグネ ット 33と、ヨーク 29bとを破 ϋで示す。  FIG. 7 is a cross-sectional view of the surface including the focusing coil 23 and the tracking coil 25 of the objective lens driving device of FIG. 6 as seen from the plus side in the X-axis direction. In FIG. 7, the movable part is indicated by a solid line, and the focusing magnet 30, the tracking magnet 32, and the yoke 29a are indicated by a broken line. FIG. 8 is a cross-sectional view of the surface including the focusing coil 24 and the tracking coil 26 of the objective lens driving device of FIG. 6 as viewed from the minus side in the X-axis direction. In FIG. 8, the movable part is indicated by a solid line, and the focusing magnet 31, the tracking magnet 33, and the yoke 29b are indicated by broken lines.
[0059] まず、フォーカシングコイル 23、 24によるフォーカシング動作について説明する。  First, the focusing operation by the focusing coils 23 and 24 will be described.
図 7に示すように、フォーカシングマグネット 30は、 ΧΥ面に平行な面上に磁極の境 界 30aを持つように X軸方向に 2極着磁されてレ、る。フォーカシングコイル 23の Y軸 方向の部分 23aと部分 23bには互いに逆向きの X軸方向の磁束が通過する。フォー カシングコイル 23に電流が供給されると、このフォーカシングコイル 23に流れる電流 と、磁気回路を構成するフォーカシングマグネット 30力もの磁束とによって、フォー力 シングコイル 23の Y軸方向部分 23a、 23bには、可動部を Z軸方向、すなわちフォー カシング方向へと駆動する電磁駆動力を発生する。  As shown in FIG. 7, the focusing magnet 30 is magnetized with two poles in the X-axis direction so as to have a magnetic pole boundary 30a on a plane parallel to the flange surface. The magnetic flux in the X-axis direction opposite to each other passes through the portion 23a and the portion 23b in the Y-axis direction of the focusing coil 23. When a current is supplied to the focusing coil 23, the current flowing in the focusing coil 23 and the magnetic flux of the focusing magnet 30 constituting the magnetic circuit cause the Y-axis direction portions 23a and 23b of the focusing coil 23 to Generates an electromagnetic drive force that drives the movable part in the Z-axis direction, that is, the focusing direction.
[0060] 図 8に示すように、フォーカシングコイル 24も同様に、磁気回路を構成するフォー力 シングマグネット 31からの X軸方向の磁束によって、可動部を Z軸方向すなわちフォ 一力シング方向へと駆動する電磁駆動力を発生する。レンズホルダ 22を含む可動部 は弾性支持部材 27によって移動可能に支持されているので、フォーカシングコイル 2 3、 24による電磁駆動力によって、対物レンズ 21は光軸と平行なフォーカシング方向 に移動する。対物レンズ 21をフォーカシング方向に移動させて、光ディスクに照射す るレーザ光のフォーカシングの調整が行われる。 [0060] As shown in FIG. 8, the focusing coil 24 also moves the movable part in the Z-axis direction, that is, the force-singing direction by the magnetic force in the X-axis direction from the focusing force magnet 31 constituting the magnetic circuit. Generates electromagnetic driving force to drive. Since the movable part including the lens holder 22 is movably supported by the elastic support member 27, the focusing coil 2 The objective lens 21 is moved in the focusing direction parallel to the optical axis by the electromagnetic driving force of 3 and 24. The objective lens 21 is moved in the focusing direction to adjust the focusing of the laser beam irradiated onto the optical disc.
[0061] 次に、トラッキングコイル 25、 26によるトラッキング動作について説明する。  Next, the tracking operation by the tracking coils 25 and 26 will be described.
図 7に示すように、トラッキングマグネット 32は、 ZX面力 X軸周りに Y軸方向にわ ずかに傾いた面上に磁極の境界 32aを持つように X軸方向に 2極着磁されている。ト ラッキングコイル 25の Z軸方向の部分 25aと部分 25bには互いに逆向きの X軸方向 の磁束が通過する。トラッキングコイル 25に電流が供給されると、トラッキングコイル 2 5の Z軸方向の部分 25a、部分 25bを流れる電流と、磁気回路を構成するトラッキング マグネット 32からの磁束とによって、 Y軸方向の電磁駆動力 FYが発生する。この電 磁駆動力 FYは、可動部をトラッキング方向（Y軸方向）へと駆動する。  As shown in Fig. 7, the tracking magnet 32 is magnetized with two poles in the X-axis direction so that it has a magnetic pole boundary 32a on a surface slightly inclined in the Y-axis direction around the ZX surface force X-axis. Yes. The magnetic flux in the X-axis direction opposite to each other passes through the portion 25a and the portion 25b in the Z-axis direction of the tracking coil 25. When a current is supplied to the tracking coil 25, an electromagnetic drive in the Y-axis direction is generated by the current flowing through the Z-axis direction portions 25a and 25b of the tracking coil 25 and the magnetic flux from the tracking magnet 32 constituting the magnetic circuit. Force FY is generated. This electromagnetic driving force FY drives the movable part in the tracking direction (Y-axis direction).
[0062] 図 8に示すように、トラッキングコイル 26も同様に、磁気回路を構成するトラッキング マグネット 33からの X軸方向の磁束によって、可動部を Y軸方向すなわちトラッキング 方向へと駆動する電磁駆動力 FYを発生する。レンズホルダ 22を含む可動部は、弹 性支持部材 27にて移動可能に支持されているので、トラッキングコイル 25、 26による 電磁駆動力 FYによって、対物レンズ 21は光軸と直交するトラッキング方向に移動す る。対物レンズ 21をトラッキング方向に移動させて、光ディスクに照射するレーザ光の トラッキングの調整が行われる。  [0062] As shown in FIG. 8, the tracking coil 26 similarly has an electromagnetic driving force that drives the movable part in the Y-axis direction, that is, the tracking direction, by the magnetic flux in the X-axis direction from the tracking magnet 33 that forms the magnetic circuit. Generate FY. Since the movable part including the lens holder 22 is movably supported by the elastic support member 27, the objective lens 21 moves in the tracking direction orthogonal to the optical axis by the electromagnetic driving force FY by the tracking coils 25 and 26. The The objective lens 21 is moved in the tracking direction to adjust the tracking of the laser beam applied to the optical disk.
[0063] さらに、本発明の実施の形態 2に係る対物レンズ駆動装置の特徴について説明す る。  [0063] Further, features of the objective lens driving device according to Embodiment 2 of the present invention will be described.
図 6に示すように、この対物レンズ駆動装置においても実施の形態 1に係る対物レ ンズ駆動装置と同様に、バランサを設けていなレ、。バランサを設けていないので、可 動部の重心と弾性支持部材 27の可動部を支持する支持中心 Gと、トラッキングコイル 25、 26の駆動中心とは Z軸方向にずれがある。そのため、電磁駆動力 FYによって、 支持中心の周りに X軸方向について右ねじ回りのトノレク TZaが発生する。なお、このト ルク TZaは、図 7では反時計回り、図 8では時計回りで示される。この X軸方向につい て右ねじ回りのトノレク TZaは、可動部を X軸周りに回転させ、対物レンズ 21の光軸が 傾く原因となる。 [0064] —方、トラッキングコイル 25には、 Z軸方向の部分 25a、 25bだけでなく、トラツキン グマグネット 32からの磁束が作用する Y軸方向の部分 25c、 25d、 25e、 25fがある。 トラッキングコイル 25に電流が供給されることにより、 Y軸方向の部分 25c、 25d、 25e 、 25fには、図 7の矢印で示す向きの Z軸方向の電磁駆動力 FZ1、 FZ2、 FZ3、 FZ4 が発生する。トラッキングコイル 26についても同様に、図 8に示すように、 Y軸方向の き分 26c、 26d、 26e、 26fに fま、 Z軸方向の電磁馬区動力 FZ5、 FZ6、 FZ7、 FZ8力 S 発生する。この Z軸方向の電磁駆動力 FZ1〜FZ8についても支持中心 Gの周りのト ルク TZbが発生する。そこで、本発明者は、実施の形態 1と同様に、トラッキングコィ ノレ 25、 26の Y軸方向の部分によって発生する Z軸方向の電磁駆動力 FZ1〜FZ8を 制御して、 Y軸方向の電磁駆動力 FYによるトノレク TZaを逆回りのトルク TZbによって 相殺して、全体の合計トルクを 0とすることに思い至った。 As shown in FIG. 6, in this objective lens driving device, as in the objective lens driving device according to Embodiment 1, a balancer is not provided. Since no balancer is provided, the center of gravity of the movable part and the support center G that supports the movable part of the elastic support member 27 and the drive center of the tracking coils 25 and 26 are displaced in the Z-axis direction. As a result, the Tonerek TZa around the right-hand thread in the X-axis direction is generated around the support center by the electromagnetic driving force FY. This torque TZa is shown counterclockwise in FIG. 7 and clockwise in FIG. The Tonerek TZa around the right-hand thread in this X-axis direction causes the movable part to rotate around the X-axis, causing the optical axis of the objective lens 21 to tilt. [0064] On the other hand, the tracking coil 25 has not only portions 25a and 25b in the Z-axis direction but also portions 25c, 25d, 25e and 25f in the Y-axis direction where the magnetic flux from the tracking magnet 32 acts. When current is supplied to the tracking coil 25, the electromagnetic driving forces FZ1, FZ2, FZ3, and FZ4 in the Z axis direction indicated by the arrows in FIG. 7 are applied to the Y axis direction portions 25c, 25d, 25e, and 25f. appear. Similarly for tracking coil 26, as shown in Fig. 8, electromagnetic force in the Z-axis direction Fc5, FZ6, FZ7, FZ8 force S is generated up to 26c, 26d, 26e, and 26f in the Y-axis direction. To do. The torque TZb around the support center G is also generated for the electromagnetic driving forces FZ1 to FZ8 in the Z-axis direction. Therefore, as in the first embodiment, the inventor controls the electromagnetic driving forces FZ1 to FZ8 in the Z-axis direction generated by the Y-axis direction portions of the tracking condensers 25 and 26 to control the electromagnetic force in the Y-axis direction. We came up with the idea that the total torque was 0 by offsetting Tonlek TZa due to driving force FY with reverse torque TZb.
[0065] 本発明者は、図 9に示すように、 ZX平面から Y軸方向のマイナス側に傾いた面 32a について磁極が反転した着磁パターンを有するトラッキングマグネット 32及び同様の トラッキングマグネット 33を用いて、トラッキングコイル 25、 26の Y軸方向の部分に生 じる電磁駆動力 FZ1〜FZ8を制御することを考えた。  As shown in FIG. 9, the present inventor uses a tracking magnet 32 having a magnetization pattern in which the magnetic poles are reversed with respect to a surface 32a inclined to the negative side in the Y-axis direction from the ZX plane, and a similar tracking magnet 33. Therefore, we considered controlling the electromagnetic driving forces FZ1 to FZ8 generated in the Y-axis direction of the tracking coils 25 and 26.
[0066] まず、トラッキングコイル 25におけるトノレク TZaの相殺について検討する。  [0066] First, consideration will be given to cancellation of tonolec TZa in the tracking coil 25.
トラッキングコイル 25の Y軸方向の部分 25e、 25fには、 Z軸方向マイナスの向きの 電磁駆動力 FZ3、 FZ4力 S発生する。部分 25c、 25dには、 Z軸方向プラスの向きの電 磁駆動力 FZ1、 FZ2が発生する。発生する電磁駆動力の大きさは、磁束の作用を受 ける長さに比例して大きくなる。トラッキングマグネット 32は、 ZX平面から Y軸方向の マイナス側に傾いた面 32aについて磁極の境界を有するものとしている。そこで、部 分 25c、 25dは、部分 25e、 25fより長くなる。 Y軸方向の部分 25c、 25d、 25e、 25f の長さを制御して、その電磁駆動力 FZ1〜FZ4を制御する。電磁駆動力 FZ1〜FZ4 を制御して、電磁駆動力 FZ1〜FZ4によるトルク TZbが、 Z軸方向の部分 25a、 25b によるトルク TZaとは逆向きで同じ大きさを有するように制御する。これによつて、トノレ ク TZbによってトルク TZaを相殺して、全体のトノレクを 0とすることができる。  Electromagnetic drive forces FZ3 and FZ4 forces S in the negative direction of the Z axis are generated in the Y axis direction parts 25e and 25f of the tracking coil 25. Electromagnetic driving forces FZ1 and FZ2 in the positive direction of the Z axis are generated in the portions 25c and 25d. The magnitude of the generated electromagnetic driving force increases in proportion to the length affected by the magnetic flux. The tracking magnet 32 has a magnetic pole boundary on a surface 32a inclined from the ZX plane to the negative side in the Y-axis direction. Therefore, the portions 25c and 25d are longer than the portions 25e and 25f. The electromagnetic driving forces FZ1 to FZ4 are controlled by controlling the lengths of the portions 25c, 25d, 25e, and 25f in the Y-axis direction. The electromagnetic driving forces FZ1 to FZ4 are controlled so that the torque TZb by the electromagnetic driving forces FZ1 to FZ4 is opposite to the torque TZa by the portions 25a and 25b in the Z-axis direction and has the same magnitude. As a result, the torque TZa is offset by the torque TZb, and the overall torque can be reduced to zero.
[0067] 次に、トラッキングコイル 26におけるトルク TZaの相殺について説明する。  Next, cancellation of the torque TZa in the tracking coil 26 will be described.
トラッキングマグネット 33は、トラッキングマグネット 32とは逆に、 ZX平面から Y軸方 向のプラス側に傾いた面 33aについて磁極の境界を有するものとしている。そこで、 部分 26c、 26dは、部分 26e、 26fより長ぐなる。 Y軸方向の部分 26c、 26d、 26e、 26 fの長さを制御して、その電磁駆動力 FZ5〜FZ8を制御する。電磁駆動力 FZ5〜FZ 8を制御して、電磁駆動力 FZ5〜FZ8によるトルク TZb力 Z軸方向の部分 26a、 26 bによるトルク TZaとは逆向きで同じ大きさを有するように制御する。これによつて、ト ルク TZbによってトルク TZaを相殺して、全体のトノレクを 0とすることができる。 The tracking magnet 33 is opposite to the tracking magnet 32. The surface 33a inclined to the plus side of the direction has a magnetic pole boundary. Therefore, the parts 26c and 26d are longer than the parts 26e and 26f. The length of the portions 26c, 26d, 26e, and 26f in the Y-axis direction is controlled to control the electromagnetic driving forces FZ5 to FZ8. By controlling the electromagnetic driving force FZ5 to FZ8, the torque TZb force by the electromagnetic driving force FZ5 to FZ8 is controlled to have the same magnitude in the opposite direction to the torque TZa by the portions 26a and 26b in the Z-axis direction. As a result, the torque TZa is offset by the torque TZb, and the entire tonolek can be made zero.
[0068] なお、この対物レンズ駆動装置において、トラッキングコイル 25、 26に生じる電磁駆 動力の合力は、トラッキング方向である Y軸方向の合力のみとし、 Z軸方向の合力を 0 とする必要がある。そこで、それぞれの方向の合力について検討する。トラッキング方 向である Y軸方向には上述のように（FY1 + FY2 + FY3 + FY4)の電磁駆動力が生 じる。一方、トラッキングコイル 25では、 Z軸方向の電磁駆動力 FZ1〜FZ4の合力は Z軸方向のプラス側の成分が残る。トラッキングコイル 26では、 Z軸方向の電磁駆動 力 FZ5〜FZ8の合力は Z軸方向のマイナス側の成分が残る。そこで、トラッキングマ グネット 32及び 33の磁極の境界面 32a、 33aを制御して、トラッキングコイル 25の部 分 25cとトラッキングコイル 26の対応する各部分とが同じ長さとなるように制御する。こ れによって、トラッキングコイル 25とトラッキングコイル 26のそれぞれの Z軸方向の電 磁駆動力 FZ1〜FZ8の合力力 SOとなる。この場合、トラッキングマグネット 32とトラツキ ングマグネット 33とは、それぞれの磁極の境界面 32a及び 33aが ZX面に対して互レヽ に対称となるように配置する。  [0068] In this objective lens driving device, the resultant force of the electromagnetic driving force generated in the tracking coils 25 and 26 must be only the resultant force in the Y-axis direction, which is the tracking direction, and the resultant force in the Z-axis direction must be zero. . Therefore, consider the resultant force in each direction. In the Y-axis direction, which is the tracking direction, the electromagnetic driving force (FY1 + FY2 + FY3 + FY4) is generated as described above. On the other hand, in the tracking coil 25, a positive component in the Z-axis direction remains in the resultant force of the electromagnetic driving forces FZ1 to FZ4 in the Z-axis direction. In the tracking coil 26, the negative force component in the Z-axis direction remains in the resultant force of the electromagnetic driving forces FZ5 to FZ8 in the Z-axis direction. Therefore, the boundary surfaces 32a and 33a of the magnetic poles of the tracking magnets 32 and 33 are controlled so that the portion 25c of the tracking coil 25 and the corresponding portions of the tracking coil 26 have the same length. As a result, the resultant force SO of the electromagnetic driving forces FZ1 to FZ8 in the Z-axis direction of the tracking coil 25 and the tracking coil 26 is obtained. In this case, the tracking magnet 32 and the tracking magnet 33 are arranged so that the boundary surfaces 32a and 33a of the magnetic poles are symmetrical with respect to the ZX plane.
[0069] 図 10は、図 7及び図 8のトラッキングコイル 25、 26に生じる電磁駆動力による支持 中心 Gに対するトルクを説明する概略図である。図 10では、トラッキングコイル 25、 2 6を点線で示している。図 7及び図 8のトラッキングコイル 25、 26の各部分に生じる電 磁駆動力を矢印で示している。また、支持中心から電磁駆動力の作用点までを直線 で示している。  FIG. 10 is a schematic diagram for explaining the torque with respect to the support center G due to the electromagnetic driving force generated in the tracking coils 25 and 26 in FIGS. 7 and 8. In FIG. 10, the tracking coils 25 and 26 are indicated by dotted lines. The electromagnetic driving force generated in each part of the tracking coils 25 and 26 in FIGS. 7 and 8 is indicated by arrows. The straight line from the support center to the point of action of the electromagnetic driving force is shown.
[0070] トラッキングコイル 25、 26の Y軸部分 25c〜25f、 26c〜26fに生じる Z軸方向の電 磁駆動力 FZ1〜FZ8については、以下のような関係となる。  [0070] The electromagnetic driving forces FZ1 to FZ8 in the Z-axis direction generated in the Y-axis portions 25c to 25f and 26c to 26f of the tracking coils 25 and 26 have the following relationship.
(a)部分 25cと部分 26cの長さを同一としている。そこで、部分 25cに生じる電磁駆動 力 FZ1は、部分 26cに生じる電磁駆動力 FZ5に対して逆向きで同じ大きさとなる。 (b)部分 25dと部分 26dの長さを同一としている。そこで、部分 25dに生じる電磁駆動 力 FZ2は、部分 26dに生じる電磁駆動力 FZ6に対して逆向きで同じ大きさとなる。(a) The length of the part 25c and the part 26c is made the same. Therefore, the electromagnetic driving force FZ1 generated in the portion 25c is the same in the opposite direction to the electromagnetic driving force FZ5 generated in the portion 26c. (b) The lengths of the part 25d and the part 26d are the same. Therefore, the electromagnetic driving force FZ2 generated in the portion 25d has the same magnitude in the opposite direction to the electromagnetic driving force FZ6 generated in the portion 26d.
(c)部分 25eと部分 26eの長さを同一としている。そこで、部分 25eに生じる電磁駆動 力 FZ3は、部分 26eに生じる電磁駆動力 FZ7に対して逆向きで同じ大きさとなる。(c) The lengths of the portion 25e and the portion 26e are the same. Therefore, the electromagnetic driving force FZ3 generated in the portion 25e has the same magnitude in the opposite direction to the electromagnetic driving force FZ7 generated in the portion 26e.
(d)部分 25fと部分 26fの長さを同一としている。そこで、部分 25fに生じる電磁駆動 力 FZ4は、部分 26fに生じる電磁駆動力 FZ8に対して逆向きで同じ大きさとなる。 以上により、 Z軸方向の電磁駆動力 FZ：!〜 FZ8の合力は 0となる。これにより、トラッ キングコイル 25、 26に生じる電磁駆動力の合力は、トラッキング方向である Y軸方向 のみとなる。 (d) The lengths of the part 25f and the part 26f are the same. Therefore, the electromagnetic driving force FZ4 generated in the portion 25f is the same in the opposite direction to the electromagnetic driving force FZ8 generated in the portion 26f. As a result, the resultant force of the electromagnetic driving force FZ :! to FZ8 in the Z-axis direction becomes zero. As a result, the resultant electromagnetic driving force generated in the tracking coils 25 and 26 is only in the Y-axis direction, which is the tracking direction.
[0071] 以上のように、実施の形態 2に係る対物レンズ駆動装置によれば、バランサを設け ないことに起因してトラッキングコイル 25、 26の駆動中心と可動部の支持中心 Gとの Z方向の位置ずれが発生する。この位置ずれによって支持中心 Gの周りに右ねじ回り のトノレク TZaが発生する。実施の形態 2では、トラッキングマグネット 32、 33を XZ面か ら X軸周りに傾いた面に磁極の境界を持つ 2極着磁の着磁パターンを有するものを 用いることを特徴としている。トラッキングマグネット 32、 33の着磁パターンを制御して 、トラッキングコイル 25、 26の Y軸方向の部分によって生じる Z軸方向の電磁駆動力 FZ1〜FZ8を制御する。この電磁駆動力 FZ1〜FZ8によって、トルク TZaと反対向き であって同じ大きさのトノレク TZbを発生させる。トルク TZaをトルク TZbによって相殺し て、全体のトノレクを 0とすることができる。これによつて、トラッキング駆動時に発生する 対物レンズの傾きを抑制することができる。これにより可動部の回転による対物レンズ 21の光軸の傾きを抑えることができる。  As described above, according to the objective lens driving device according to Embodiment 2, the Z direction between the drive center of the tracking coils 25 and 26 and the support center G of the movable part due to the absence of the balancer. The position shift occurs. This misalignment generates Tonlek TZa around the support center G around the right-hand thread. The second embodiment is characterized in that the tracking magnets 32 and 33 each have a two-pole magnetization pattern having a magnetic pole boundary on a surface inclined about the X axis from the XZ plane. By controlling the magnetization pattern of the tracking magnets 32 and 33, the electromagnetic driving forces FZ1 to FZ8 in the Z-axis direction generated by the Y-axis direction portions of the tracking coils 25 and 26 are controlled. The electromagnetic drive forces FZ1 to FZ8 generate a tonolek TZb that is opposite in direction to the torque TZa and has the same magnitude. Torque TZa can be offset by torque TZb, and the overall tonolec can be reduced to zero. This can suppress the tilt of the objective lens that occurs during tracking drive. Thereby, the inclination of the optical axis of the objective lens 21 due to the rotation of the movable part can be suppressed.
[0072] なお、本実施の形態 2ではトラッキングマグネット 32、 33を XZ面から X軸周りに傾い た面に磁極の境界を持つ 2極着磁とした力 これに限られなレ、。例えば、トラッキング マグネット 32， 33は、トラッキングコイル 25、 26と対向する同一磁極の上辺と下辺の 部分の長さが異なるようにして、中間部分はクランク状の磁極の境界を持つ 2極着磁 としてもよレ、。この場合にも同様にトラッキングコイルの Y軸方向部分によって支持中 心についてトルク TZaとは逆回りであって同じ大きさのトルク TZbを発生させることが でき、同等の効果が得られる。 [0073] なお、本実施の形態 2においてトラッキングコイル 25、 26の形状は、略長方形であ るが、これに限られず、円形、長円形であっても同等の効果が得られる。 [0072] In the second embodiment, the tracking magnets 32 and 33 have a magnetic pole boundary on the surface inclined from the XZ plane around the X axis. The force is not limited to this. For example, the tracking magnets 32 and 33 are two-pole magnetized so that the lengths of the upper and lower sides of the same magnetic pole facing the tracking coils 25 and 26 are different, and the middle part has a crank-shaped magnetic pole boundary. Moyore. In this case as well, the Y-axis portion of the tracking coil can generate the same magnitude of torque TZb in the reverse direction of the torque TZa at the support center, and the same effect can be obtained. In the second embodiment, the shapes of the tracking coils 25 and 26 are substantially rectangular. However, the shape is not limited to this, and the same effect can be obtained even if the shape is circular or oval.
[0074] また、上記実施の形態 1及び 2の対物レンズ駆動装置は、光ヘッド装置に組み込む こと力 Sできる。さらに、この光ヘッド装置を光ディスク装置に組み込むことができる。  In addition, the objective lens driving device according to the first and second embodiments can be incorporated into the optical head device. Furthermore, this optical head device can be incorporated into an optical disk device.
[0075] 上述の通り、本発明は好ましい実施の形態により詳細に説明されているが、本発明 はこれらに限定されるものではなぐ特許請求の範囲に記載された本発明の技術的 範囲内において多くの好ましい変形例及び修正例が可能であることは当業者にとつ て自明なことであろう。  [0075] As described above, the present invention has been described in detail with reference to the preferred embodiments. However, the present invention is not limited thereto, and is within the technical scope of the present invention described in the claims. It will be apparent to those skilled in the art that many preferred variations and modifications are possible.
産業上の利用可能性  Industrial applicability
[0076] 本発明に係る対物レンズ駆動装置は、トラッキングの駆動力中心と可動部重心、支 持中心の位置を一致させる必要がなレ、。そこで、可動部にバランサを付加する必要 がなぐ薄型でかつ高加速度を得ることが可能になり、薄型でかつ再生信号の劣化 が少ない光ディスク装置に用いることができる。 In the objective lens driving device according to the present invention, it is not necessary to match the positions of the tracking driving force center, the center of gravity of the movable part, and the supporting center. Therefore, it is possible to obtain a thin and high acceleration that does not require the addition of a balancer to the movable part, and it can be used for an optical disc apparatus that is thin and has little deterioration in the reproduction signal.

Claims

請求の範囲 The scope of the claims
[1] 光記録媒体に光学的に情報を記録または再生するための対物レンズを駆動する対 物レンズ駆動装置であって、  [1] An object lens driving device for driving an objective lens for optically recording or reproducing information on an optical recording medium,
前記対物レンズを含む光学系が取り付けられたレンズホルダと、  A lens holder to which an optical system including the objective lens is attached;
一端が前記レンズホルダに取り付けられ、他端が固定部材に取り付けられ、前記レ ンズホルダを、前記光記録媒体の記録面に垂直なフォーカシング方向と、前記フォ 一力シング方向と垂直なトラッキング方向とのそれぞれの方向に対して移動可能に前 記固定部材について弾性支持する支持部材と、  One end is attached to the lens holder, and the other end is attached to a fixing member. The lens holder includes a focusing direction perpendicular to the recording surface of the optical recording medium and a tracking direction perpendicular to the forcing direction. A support member that elastically supports the fixing member so as to be movable in each direction;
前記フォーカシング方向と前記トラッキング方向とのそれぞれの方向に対して垂直 な方向に平行な卷回軸を有し、前記レンズホルダに固定された少なくとも一対の第 1 及び第 2のトラッキングコイルと、  At least a pair of first and second tracking coils having a winding axis parallel to a direction perpendicular to each of the focusing direction and the tracking direction, and fixed to the lens holder;
前記第 1及び第 2のトラッキングコイルに電磁力を発生させるように磁界を付与する マグネットと、  A magnet for applying a magnetic field so as to generate an electromagnetic force in the first and second tracking coils;
を備え、  With
前記第 1及び第 2のトラッキングコイルの駆動中心軸は、前記第 1及び第 2のトラツキ ングコイルの中心のそれぞれの卷回軸の中間に延在する軸として規定され、前記駆 動中心軸は、前記対物レンズ駆動装置の重心を通らなレ、と共に、  The drive center axes of the first and second tracking coils are defined as axes extending in the middle of the respective winding axes of the centers of the first and second tracking coils, and the drive center axes are Along with passing through the center of gravity of the objective lens driving device,
前記マグネットは、前記第 1及び第 2のトラッキングコイルに発生させる前記電磁力 によって生じるトルクの合計が 0となる着磁パターンを有することを特徴とする対物レ ンズ駆動装置。  2. The objective lens driving device according to claim 1, wherein the magnet has a magnetization pattern in which a total torque generated by the electromagnetic force generated by the first and second tracking coils is zero.
[2] 前記対物レンズ駆動装置の支持中心軸は、前記対物レンズ駆動装置の前記重心 を通ると共に、前記トラッキング方向と前記フォーカシング方向とを含む面に対して垂 直に延在する軸として規定され、  [2] The support central axis of the objective lens driving device is defined as an axis that passes through the center of gravity of the objective lens driving device and extends perpendicularly to a plane including the tracking direction and the focusing direction. ,
前記マグネットは、前記マグネットが対向する前記第 1及び第 2のトラッキングコィノレ の各部分と前記支持中心軸との距離に応じた着磁パターンを有することを特徴とす る請求項 1に記載の対物レンズ駆動装置。  2. The magnet according to claim 1, wherein the magnet has a magnetized pattern corresponding to a distance between each portion of the first and second tracking coinors opposed to the magnet and the support center axis. Objective lens drive.
[3] 前記マグネットは、前記トラッキング方向と前記フォーカシング方向とを含む面内で[3] The magnet is within a plane including the tracking direction and the focusing direction.
、前記第 1及び第 2のトラッキングコイルの中心のそれぞれの卷回軸を結ぶ線につい て非線対称の着磁パターンを有することを特徴とする請求項 1に記載の対物レンズ 駆動装置。 And a line connecting the winding axes of the centers of the first and second tracking coils. 2. The objective lens driving device according to claim 1, wherein the objective lens driving device has a non-axisymmetric magnetization pattern.
[4] 前記マグネットは、前記トラッキング方向と前記フォーカシング方向とを含む面内で [4] The magnet is within a plane including the tracking direction and the focusing direction.
、前記フォーカシング方向についてテーパ状の形状を有することを特徴とする請求項And a tapered shape in the focusing direction.
1に記載の対物レンズ駆動装置。 2. The objective lens driving device according to 1.
[5] 前記マグネットは、前記トラッキング方向と前記フォーカシング方向とを含む面内で[5] The magnet is within a plane including the tracking direction and the focusing direction.
、前記フォーカシング方向について凸型形状を有することを特徴とする請求項 1に記 載の対物レンズ駆動装置。 The objective lens driving device according to claim 1, wherein the objective lens driving device has a convex shape in the focusing direction.
[6] 前記マグネットは、前記第 1のトラッキングコイルに電磁力を発生させる第 1マグネッ トと、前記第 2のトラッキングコイルに電磁力を発生させる第 2マグネットとを備えること を特徴とする請求項 1に記載の対物レンズ駆動装置。 [6] The magnet includes a first magnet that generates an electromagnetic force in the first tracking coil and a second magnet that generates an electromagnetic force in the second tracking coil. 2. The objective lens driving device according to 1.
[7] 前記マグネットは、前記第 1及び第 2のトラッキングコイルに対して、それぞれの卷回 軸に平行な磁束を作用させることを特徴とする請求項 1に記載の対物レンズ駆動装 置。 7. The objective lens driving device according to claim 1, wherein the magnet causes a magnetic flux parallel to each winding axis to act on the first and second tracking coils.
[8] 前記マグネットは、前記トラッキング方向と前記フォーカシング方向とを含む面内で 、前記第 1及び第 2のトラッキングコイルの前記駆動中心軸と交差し、前記フォーカシ ング方向に平行な線について線対称の着磁パターンを有することを特徴とする請求 項 1に記載の対物レンズ駆動装置。  [8] The magnet is axisymmetric with respect to a line that intersects the drive center axis of the first and second tracking coils and is parallel to the focusing direction within a plane including the tracking direction and the focusing direction. The objective lens driving device according to claim 1, wherein the objective lens driving device has a magnetization pattern of:
[9] 前記マグネットは、着磁部分と非着磁部分とを含む着磁パターンを有することを特 徴とする請求項 1に記載の対物レンズ駆動装置。  9. The objective lens driving device according to claim 1, wherein the magnet has a magnetization pattern including a magnetized portion and a non-magnetized portion.
[10] 前記マグネットは、前記フォーカシング方向力 傾いた磁極の境界を有する 2極着 磁の着磁パターンを有することを特徴とする請求項 1に記載の対物レンズ駆動装置。  10. The objective lens driving device according to claim 1, wherein the magnet has a two-pole magnetized pattern having a boundary between magnetic poles inclined in the focusing direction force.
[11] 請求項 1に記載の対物レンズ駆動装置を備えたことを特徴とする光学ヘッド装置。  [11] An optical head device comprising the objective lens driving device according to [1].
[12] 請求項 11に記載の光学ヘッド装置を備えたことを特徴とする光ディスク装置。  12. An optical disk device comprising the optical head device according to claim 11.
PCT/JP2007/056205 2006-03-27 2007-03-26 Objective lens driving apparatus WO2007116684A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8778594B2 (en) 2011-07-19 2014-07-15 Sumitomo Chemical Company, Limited Resist composition and method for producing resist pattern

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62287444A (en) * 1986-06-06 1987-12-14 Pioneer Electronic Corp Lens driving device
JP2001222830A (en) * 2000-02-08 2001-08-17 Pioneer Electronic Corp Lens drive assembly of disk player

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62287444A (en) * 1986-06-06 1987-12-14 Pioneer Electronic Corp Lens driving device
JP2001222830A (en) * 2000-02-08 2001-08-17 Pioneer Electronic Corp Lens drive assembly of disk player

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8778594B2 (en) 2011-07-19 2014-07-15 Sumitomo Chemical Company, Limited Resist composition and method for producing resist pattern

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