JP2008041180A - Optical pickup - Google Patents

Abstract

An optical pickup having high servo stability while suppressing unnecessary resonance such as rolling is provided.
SOLUTION: A lens holder 2 to which objective lenses 21 and 22 are attached, a support body 3, elastic support members 6a to 6f respectively connecting the lens holder 2 and the support body 3, one side surface of the lens holder 2, and Focus coils 12a to 12d provided on the other side surface, tracking coils 11a and 11b provided on one side surface and the other side surface of the lens holder 2, magnets 13 and 14, and focus coil 12a provided on one side surface , 12b and the focus coils 12c, 12d provided on the other side surface are respectively provided with drive current supply means for supplying drive currents independently, and the focus coils 12a, 12b and the focus coils 12c, 12d Is determined according to the position of the lens holder 2 in the focus direction and the tracking direction, respectively. The drive current is supplied.
[Selection] Figure 3

Description

  The present invention relates to an optical pickup used for recording an information signal on an optical disc and reproducing the information signal recorded on the optical disc.

  Conventionally, optical discs such as CDs (Compact Discs) and DVDs (Digital Versatile Discs) have been used as recording media for information signals. Information signals are recorded on this type of optical discs, or information signals recorded on optical discs are reproduced. There is an optical disc device for performing the above-mentioned, and this optical disc device is provided with an optical pickup that is moved in the radial direction of the optical disc and irradiates the optical disc with a light beam.

  The optical pickup is provided with an objective lens driving device, and by this objective lens driving device, the focus coil is moved in the focus direction, which is the direction in which the objective lens held by the movable part is separated from or close to the signal recording surface of the optical disk. To adjust the focus by moving the objective lens by the tracking coil in the tracking direction which is substantially the radial direction of the optical disc.

  In addition, the objective lens driving device performs tilt adjustment by operating the tilt coil in a tilt direction that is a rotation direction around a tangential direction (jitter direction) that is a direction perpendicular to the focus direction and the tracking direction. The spot adjustment of the light beam applied to the optical disc via the optical disk is performed so that the spot of the light beam applied to the optical disc via the objective lens is condensed on the recording track of the optical disc.

  As shown in FIGS. 15 and 16, the objective lens driving device 201 of the optical pickup 200 often drives the objective lenses 204 and 205 provided in the movable portion 202 to face the disc. Focus coils 212 a to 212 d and tracking coils 211 a and 211 b are provided on the front and back side surfaces of the movable unit 202 that is cantilevered from the support unit 203 by the support arm 206.

  In the optical pickup 200, the coils 211a, 211b, and 212a to 212d are supplied with a drive current determined by the DSP 220 shown in FIG. The DSP 220 includes a control calculation unit 222 for the focus coil and a control calculation unit 223 for the tracking coil. The control calculation unit 222 supplies a focus drive current to the focus coils 212 a to 212 d via the drive amplifier circuit 224 based on the focus error signal FE supplied via the matrix amplifier 221. The control operation unit 223 supplies a tracking drive current to the tracking coils 211 a and 211 b via the drive amplifier circuit 225 based on the tracking error signal TE supplied via the matrix amplifier 221. The matrix amplifier 221 detects various signals such as FE and TE based on the amount of light received by the optical detector 219 provided in the optical pickup and the reflected light on the signal recording surface of the optical disc 102.

  The optical pickup 200 includes a movable portion 202 and a tracking portion in a focus direction and a tracking direction by a magnetic field formed by magnets 213 and 214 provided to face the coils 211a, 211b, and 212a to 212d and a current supplied to the coils. The objective lens provided on this can be displaced.

  In the optical pickup 200, when a difference occurs in the thrust of the drive coils provided on the front and rear side surfaces of the movable portion 202, the rotational force around the axis in the focus direction F and the axis around the tracking direction T A rotational force is generated. The rolling Yro and Zro due to these rotational forces adversely affects the transfer characteristics in the focus direction, tracking direction, and tilt direction, and makes the servo circuit unstable.

  Further, in the optical pickup 200, the driving provided on the front and back side surfaces of the movable portion 202 due to variations in the displacement, thickness difference, winding disturbance, etc. of the focus coils 212a to 212d or the tracking coils 211a and 211b, that is, the arrangement error and the manufacturing error. If there is a difference in the thrust of the coil, or the rotational axis shifts due to mass imbalance, that is, the center of the driving thrust of the focus coils 212a to 212d or the center of the driving thrust of the tracking coils 211a and 211b, and the movable part When a rotational force (rolling torque) is generated due to a deviation from the center of gravity position of 202, the rolling Yro and Zro generated thereby adversely affect the transfer characteristics in the focus direction, tracking direction, and tilt direction, Make servo circuit unstable There is a problem to say.

  In particular, in addition to the conventional CD and DVD, a plurality of objective lenses are used for three-wavelength compatibility corresponding to a high-density recording optical disk capable of higher density recording using a light source having a wavelength of about 400 to 415 nm by a blue-violet semiconductor laser. In the objective lens driving device used for the mounted optical pickup, it is impossible to match the rotation center and the lens mounting position. Therefore, the influence of rolling Yro and Zro is very large, and it is very difficult to stabilize the servo circuit. It has become.

  Here, the rolling Yro generated by the thrust of the focus coil will be specifically described with reference to FIG.

  The front focus coils 212a and 212b and the rear focus coils 212c and 212d are connected in series and supplied with the same current, but there is a difference in the distance (gap) g10 and g20 between the opposing magnets 213 and 214. In some cases, there is a difference in driving force (thrust force) between the front and rear focus coils, a rotational force f3 is generated in the objective lens driving device, and rolling Yro around the axis in the tracking direction T is generated. It becomes.

  Further, when the objective lens driving device strokes in the focus direction F and the tracking direction T, the distance between the opposing magnets 213 and 214 and the coils 212a to 212d changes, so the amount of Yro generated depends on the focus stroke and the tracking stroke. Change. For example, when a stroke is made in the focus direction, the magnets 213 facing the front focus coils 212a and 212b even when the distances between the front focus coil and the rear focus coil and the magnets facing each other are the same before the stroke, , And the distance between the rear focus coils 212c and 212d and the magnet 214 facing each other is reduced, resulting in a difference in thrust between the front and rear focus coils. Therefore, the above-described rolling Yro occurs.

  Next, the rolling Zro generated by the thrust of the tracking coil will be specifically described with reference to FIG.

  The front tracking coil 211a and the rear tracking coil 211b are connected in series and supplied with the same current. However, when there are differences in the gaps (gap) g10 and g20 between the opposing magnet 213, etc. A difference in driving force (thrust) due to the front and rear tracking coils is generated, a rotational force f4 is generated in the objective lens driving device, and rolling Zro around the axis in the focus direction F is generated.

  Further, when the objective lens driving device strokes in the focus direction F and the tracking direction T, the distance between the opposing magnets 213 and 214 and the coils 211a and 211b changes, so the amount of Zro generated depends on the focus stroke and the tracking stroke. Change. For example, when a stroke is made in the tracking direction, the front tracking coil 211a is used even when the distance (gap) between the front tracking coil 211a and the rear tracking coil 211b and the magnets 213 and 214 facing each other is the same before the stroke. And the magnet 213 facing each other are increased, the distance between the rear tracking coil 211b and the magnet 214 facing each other is decreased, and a difference in thrust between the front and rear tracking coils is generated, so that the above-described rolling Zro occurs. End up.

  Further, in addition to the rolling Yro and Zro described with reference to FIGS. 15 and 16, the effect of the driving thrust due to variations in the displacement of the focus coils 212a to 212d and the tracking coils 211a and 211b, thickness differences, winding disturbances, and the like. When the point shifts, the rotational force, which is the torque with respect to the axis of rotation, changes, and rolling Yro and Zro occur when the rotational force is not offset by the front and rear coils.

  Furthermore, if the weight distribution of the movable part 202 changes due to variations in the weight of each of the coils 212a to 212d, 211a, 211b and the adhesive, solder, etc. for integrating them into the movable part, the center of gravity of the movable part is obtained. However, the above-described rotation axis itself moves, and rolling Yro and Zro are generated by changing the rotational force by changing the distance from the driving thrust of the front and rear coils to the center of gravity.

JP 2001-134963 A

  The object of the present invention is to provide a driving force for a focus coil or tracking coil provided on one side of the lens holder and a focus coil provided on the other side even when the lens holder is displaced in the focus direction and / or the tracking direction. Alternatively, it prevents the difference between the driving force of the tracking coil and suppresses unnecessary resonance caused by rolling or other swinging that occurs around the axis of the tracking direction or the focus direction due to the difference of the driving force. It is to provide an optical pickup having the following.

  In order to achieve this object, an optical pickup according to the present invention is provided with an objective lens for condensing a light beam on a signal recording surface of a rotationally driven optical disc, and a focus direction parallel to the optical axis of the objective lens; A lens holder that is moved in a tracking direction orthogonal to the optical axis direction of the objective lens, and a support that is disposed with a gap in the focus direction and a tangential direction orthogonal to the tracking direction with respect to the lens holder. An elastic support member that connects the body, the lens holder, and the support, and supports the lens holder movably in the focus direction and the tracking direction with respect to the support, and the tanger of the lens holder. Provided on one side and the other side in the direction of A focus coil to be generated, a tracking coil that is provided on one side surface and the other side surface of the lens holder in the tangential direction, and generates a driving force in the tracking direction, respectively, and the above-mentioned provided on the one side surface and the other side surface A drive current is independently supplied to the focus coil and the magnet disposed opposite to the tracking coil, the focus coil provided on the one side surface, and the focus coil provided on the other side surface. A focus coil provided on the one side surface and a focus coil provided on the other side surface in accordance with the positions of the lens holder in the focus direction and the tracking direction, respectively. The drive current determined in this way is supplied.

  In the optical pickup according to the present invention, an objective lens for condensing a light beam is attached to the signal recording surface of a rotationally driven optical disc, and the focus direction parallel to the optical axis of the objective lens and the light of the objective lens A lens holder that is moved in a tracking direction orthogonal to the axial direction; a support that is disposed with a gap in the tangential direction orthogonal to the focus direction and the tracking direction relative to the lens holder; and the lens An elastic support member that connects the holder and the support, and supports the lens holder so as to be movable in the focus direction and the tracking direction with respect to the support; and one of the lens holders in the tangential direction. Focusers that are provided on the side surface and the other side surface and generate driving force in the focus direction. A coil, a tracking coil provided on one side surface and the other side surface of the lens holder in the tangential direction, each generating a driving force in the tracking direction, the focus coil provided on the one side surface and the other side surface, Driving current supply for independently supplying driving current to the magnet disposed opposite to the tracking coil, the tracking coil provided on the one side surface, and the tracking coil provided on the other side surface And the tracking coil provided on the one side surface and the tracking coil provided on the other side surface are determined according to the position of the lens holder in the focus direction and the tracking direction, respectively. Drive current is supplied.

  In the present invention, the driving current determined according to the position of the lens holder in the focus direction and the tracking direction is independently applied to the focus coil provided on one side of the lens holder and the focus coil provided on the other side. To prevent the difference between the driving thrust generated by the focus coil provided on one side and the driving thrust generated by the focus coil provided on the other side. Therefore, it is possible to obtain high servo stability by suppressing unnecessary resonance caused by the swinging motion generated by the above-described operation.

  Further, the present invention provides a driving current determined by the tracking coil provided on one side surface of the lens holder and the tracking coil provided on the other side surface according to the focus direction and the tracking direction position of the lens holder. By independently supplying, the driving thrust generated by the tracking coil provided on one side surface and the driving thrust generated by the tracking coil provided on the other side surface are prevented from producing a difference. It is possible to obtain high servo stability by suppressing unnecessary resonance due to the swinging operation caused by the difference between the two.

  Hereinafter, an optical disk apparatus using an optical pickup to which the present invention is applied will be described with reference to the drawings.

  As shown in FIG. 1, an optical disc apparatus 101 to which the present invention is applied has a spindle as a driving means for rotationally driving an optical disc 102 as an optical recording medium such as a CD, a DVD, a CD-R, a DVD ± R, and a DVD-RAM. A motor 103, an optical pickup 1, and a feed motor 105 as drive means for moving the optical pickup 1 in the radial direction thereof are provided. Here, the spindle motor 103 is controlled by the system controller 107 and the control circuit unit 109 so as to be driven at a predetermined rotational speed.

  The signal modulation / demodulation unit and ECC block 108 modulates and demodulates a signal output from the signal processing unit 120 and adds an ECC (error correction code). The optical pickup 1 irradiates the signal recording surface of the optical disc 102 rotating according to instructions from the system controller 107 and the control circuit unit 109 with a light beam. Information signals are recorded on the optical disc 102 by such light beam irradiation, and the information signals recorded on the optical disc are reproduced.

  The optical pickup 1 detects various light beams as will be described later based on the reflected light beam reflected from the signal recording surface of the optical disc 102 and sends detection signals obtained from the respective light beams to the signal processing unit 120. It is configured to supply.

  The signal processing unit 120 generates various servo signals based on detection signals obtained by detecting each light beam, that is, a focus error signal and a tracking error signal, and is an information signal recorded on the optical disc. An RF signal is generated. Further, predetermined processing such as demodulation and error correction processing based on these signals is performed by the control circuit unit 109, the signal modulation / demodulation unit, the ECC block 108, and the like according to the type of recording medium to be reproduced.

  Here, if the recording signal demodulated by the signal modulation / demodulation unit and the ECC block 108 is for data storage of a computer, for example, it is sent to the external computer 130 or the like via the interface 111. Accordingly, the external computer 130 and the like are configured to receive a signal recorded on the optical disc 102 as a reproduction signal.

  In addition, if the recording signal demodulated by the signal modulation / demodulation unit and the ECC block 108 is for audio / visual use, the digital / analog conversion is performed by the D / A conversion unit of the D / A and A / D converter 112 and the audio / visual conversion is performed. It is supplied to the processing unit 113. Audio / video signal processing is performed by the audio / visual processing unit 113 and transmitted to an external imaging / projection device via the audio / visual signal input / output unit 114.

  A feed motor 105 is connected to the optical pickup 1. The optical pickup 1 is fed in the radial direction of the optical disc 102 by the rotation of the feed motor 105 and moved to a predetermined recording track on the optical disc 102. The control of the spindle motor 103, the control of the feed motor 105, and the control of the actuator that moves and displaces the objective lens of the optical pickup 1 in the focus direction that is the optical axis direction and the tracking direction orthogonal to the optical axis direction are respectively control circuits. This is performed by the unit 109.

  That is, the control circuit unit 109 controls the spindle motor 103 and controls the actuator based on the focus error signal and the tracking error signal.

  The control circuit unit 109 is driven to supply tracking coils 11a and 11b and focus coils 12a to 12d, which will be described later, based on a focus error signal, a tracking error signal, an RF signal, and the like input from the signal processing unit 120. Each of the signals (drive currents) is generated.

  The laser control unit 121 controls a laser light source in the optical pickup 1.

  Here, the focus direction F refers to the optical axis direction of the objective lenses 21 and 22 (see FIG. 3) of the optical pickup 1, and the tangential direction Tz is a direction orthogonal to the focus direction F and is the optical disc apparatus 101. The tracking direction T is a direction orthogonal to the focus direction F and the tangential Tz direction. In addition, a difference angle in which an angle formed by the optical axis of the objective lenses 21 and 22 and a virtual line passing through the optical axis and extending in the radial direction of the optical disc 102 is shifted from 90 degrees is a tilt angle in the radial direction. That's it.

  In addition, the optical disc apparatus 101 is provided with a tilt detection unit that detects the tilt of the optical disc 102 mounted on the spindle motor 103 based on the jitter amount or the like. A detection signal detected by the inclination detection unit is supplied to the control circuit unit 109. The control circuit unit 109 outputs a tilt angle control signal based on the tilt detection signal and supplies the tilt angle control signal to the driving unit 5 described later. The drive means 5 adjusts the tilt angle by driving and displacing the objective lenses 21 and 22 with a drive current according to the tilt angle control signal.

  Next, the optical pickup 1 to which the present invention is applied will be described in detail.

  The optical pickup 1 is an optical disc that records and / or reproduces information signals with respect to a plurality of types of optical discs 102 on which information signals are recorded or reproduced by selectively using a plurality of types of light beams having different wavelengths. Specifically, a first optical disk on which an information signal is recorded or reproduced using a light beam having a wavelength of about 400 to 410 nm and a light beam having a wavelength of about 650 to 660 nm are used. Information signal recording and / or recording with respect to the second optical disk on which information signals are recorded or reproduced and the third optical disk on which information signals are recorded or reproduced using a light beam with a wavelength of about 760 to 800 nm A description will be given assuming that reproduction is performed.

  In the following description, the optical pickup 1 is described as performing recording and / or reproduction of information signals with respect to three different types of optical discs. However, the present invention is not limited to this, and a plurality of different types or one type of optical discs are used. The information signal may be recorded and / or reproduced.

  An optical pickup 1 to which the present invention is applied includes a semiconductor laser as a light source that emits a plurality of types of light beams having different wavelengths, and a light detection element that detects a reflected light beam reflected from the signal recording surface of the optical disk 102. And an optical system that guides the light beam from the semiconductor laser to the optical disc 102 and guides the light beam reflected by the optical disc 102 to the light detection element.

  Further, as shown in FIG. 2, the optical pickup 1 includes the mounting base 9 in which the above-described optical system is disposed and is movable in the radial direction of the optical disk 102 within the housing of the optical disk apparatus 101, and the mounting base. And an objective lens driving device 7 disposed on the table 9. The mounting base 9 has bearing portions 10a and 10b at both ends thereof, and the bearing portions 10a and 10b are slidably supported by guide shafts (not shown). When a rack member (not shown) provided on the mounting base 9 is screwed to the lead screw and the lead screw is rotated by the feed motor, the rack member is sent in a direction corresponding to the rotation direction of the lead screw, and the optical pickup 1 Are moved in the radial direction of the optical disk 102.

  The optical pickup 1 includes a lens holder 2 that supports a plurality of objective lenses 21 and 22 that collect a light beam emitted from a light source and irradiate the optical disk as shown in FIGS. To a tangential direction Tz and a support 3 attached to an attachment base. The first and second objective lenses 21 and 22 constitute a part of the optical system of the optical pickup 1. Here, the lens holder 2 and the support 3 together with the elastic support member 4, the drive means 5 and the support arms 6 a to 6 f, which will be described later, the objective lenses 21 and 22 held by the lens holder 2 as a movable part are used as optical signal signals. An objective lens driving device 7 that enables focus adjustment by operating in the focus direction with respect to the recording surface, tracking adjustment by operating in the tracking direction, and tilt adjustment by operating in the tilt direction. The light beam is condensed on a predetermined recording track of the optical disk via the objective lens, and the condensed spot can be adjusted.

  Here, the first objective lens 21 is used for condensing, for example, a light beam having a wavelength of 650 to 660 nm and a light beam having a wavelength of 760 to 800 nm on the second or third optical disk, The second objective lens 22 is used for condensing a light beam having a wavelength of 400 to 410 nm on the first optical disk. The first and second objective lenses 21 and 22 are arranged in parallel in the tangential direction Tz. Here, the first objective lens 21 is provided on the support body 3 side, which is a fixed portion side of support arms 6a to 6f described later, and the second objective lens 22 is provided on the distal end side of the lens holder 2. Is located.

  The optical pickup 1 is configured to include a plurality of objective lenses 21 and 22 that are arranged side by side in the tangential direction Tz. However, the number and arrangement of the objective lenses are not limited thereto, and for example, a plurality of objective lenses may be provided. The objective lens may be configured to be arranged in the radial direction, or may be configured to include one objective lens.

  As shown in FIGS. 3 and 4, the lens holder 2 is provided so as to surround the outer peripheral surfaces of the first and second objective lenses 21 and 22, and the first and second objective lenses 21 and 22 are used as objectives. The lens is supported so as to be movable in a focus direction F parallel to the optical axis of the lens and a tracking direction T orthogonal to the optical axis.

  As shown in FIGS. 3, 4, and 5, the tracking direction T, which is a substantially radial direction of the optical disc 102, is disposed on the side surface facing the tangential direction Tz orthogonal to the focus direction F and the tracking direction T of the lens holder 2. First and second tracking coils 11a and 11b that generate a driving force, and first to fourth focus coils 12a and 12b that generate a driving force in a focus direction F that is a direction approaching and separating from the optical disc 102. 12c and 12d are attached. Here, the first tracking coil 11a and the first and second focus coils 12a and 12b are provided on the side surface on the distal end side, which is one of the side surfaces of the lens holder 2, and the second tracking coil 11b and the second tracking coil 11b. The third and fourth focus coils 12 c and 12 d are provided on the side surface on the base end side that is the other side surface of the lens holder 2.

  On both side surfaces spaced apart in the tracking direction T of the lens holder 2, there are provided support arms 6a, 6b, 6c and arm support portions 24 for supporting the support arms 6d, 6e, 6f, which are provided at intervals in the focus direction F, respectively. It has been. The support arms 6 a to 6 f function as elastic support members that support the lens holder 2 so as to be movable in the focus direction and the tracking direction with respect to the support 3.

  As shown in FIG. 3, a yoke 18 is disposed between the lens holder 2 and a mounting base (not shown). The yoke 18 is attached to the base 8 and fixed to the attachment base. An opening for transmitting a light beam incident on the first and second objective lenses 21 and 22 is provided at a substantially central portion of the yoke 18.

  On both sides of the yoke 18 in the tangential direction Tz, as shown in FIG. 3, a pair of yoke pieces 18a and 18b are formed so as to face each other with the first and second objective lenses 21 and 22 therebetween. . First and second magnets 13 and 14 are attached to opposing surfaces of the yoke pieces 18a and 18b. Here, the first magnet 13 is disposed on the movable portion side, that is, the tip end side of the lens holder 2, and the second magnet 14 is disposed on the fixed portion side, that is, the support body 3 side.

  As shown in FIG. 3 and FIG. 6A, the first magnet 13 is disposed to face the lens holder 2 in the tangential direction Tz, and the magnetization direction in each region is the tangential direction Tz. It has 1st thru | or 4th division area 13a, 13b, 13c, 13d magnetized toward any one.

  Here, the first divided region 13a is formed in a substantially rectangular shape, and is magnetized so that the surface on the lens holder 2 side has an N pole. The second divided region 13b has a portion adjacent to the focus direction F of the first divided region 13a and a portion adjacent to the tracking direction T, and one of the focus directions of the first divided region 13a and the tracking direction. And is magnetized in the opposite direction to the first divided region 13b, that is, so that the surface on the lens holder 2 side becomes an S pole. The third and fourth divided regions 13c and 13d are magnetized so as to be symmetrical with the first and second divided regions 13a and 13b with respect to the focus direction F, respectively.

  The S pole and the N pole of the first to fourth divided regions of the first magnet 13 described above are not limited to this, and may be reversed, for example.

  As shown in FIGS. 3 and 6B, the second magnet 14 is disposed on the opposite side of the first magnet 13 with respect to the lens holder 2 so as to face the tangential direction Tz. 13 have fifth to eighth divided areas 14 a, 14 b, 14 c, 14 d which are divided areas having the same shape as 13.

  The S pole and N pole of the fifth to eighth divided regions of the second magnet 14 described above may be reversed.

  As described above, the first and second magnets 13 and 14 are opposed to the tracking coils 11a and 11b and the focus coils 12a to 12d attached to the opposite side surfaces of the lens holder 2, respectively. A predetermined magnetic field is applied to each of the coils arranged.

  As shown in FIGS. 6A and 6B, the tracking coils 11a and 11b are portions adjacent to the tracking direction T of the second and fourth divided regions 13b and 13d of the first magnet 13, respectively. And the magnetic field formed by these divided areas, and the coils, which are arranged at positions facing the portions of the second magnet 14 adjacent to the tracking direction T of the sixth and eighth divided areas 14b and 14d. A driving force is generated in the tracking direction T depending on the direction and magnitude of the current flowing through the.

  As shown in FIGS. 6A and 6B, the focus coils 12a to 12d are portions adjacent to the focus direction F of the first and second divided regions 13a and 13b of the first magnet 13, respectively. A portion of the first magnet 13 adjacent to the focus direction F of the third and fourth divided regions 13c and 13d, a fifth and sixth divided regions 14a and 14b of the second magnet 14, and a second The magnet 14 is arranged at a position facing the seventh and eighth divided regions 14c and 14d, and the focus is determined by the magnetic field formed by these divided regions and the direction and magnitude of the current flowing through each coil. A driving force is generated in the direction F.

  As described above, the tracking magnet 11a and the focus coils 12a and 12b are opposed to the first magnet 13, and the tracking coil 11b and the focus coils 12c and 12d are opposed to the second magnet 14 so that each tracking coil 11a and When the tracking drive current is supplied to 11b, the lens holder 2 is driven and displaced in the tracking direction T by the interaction between the drive current supplied to each tracking coil and the magnetic field from each magnet 13 and 14, and each focus. When the focus drive current is supplied to the coils 12a to 12d, the lens holder 2 is driven and displaced in the focus direction F by the interaction between the drive current supplied to the focus coil and the magnetic fields from the magnets 13 and 14.

  As a result, the first and second objective lenses 21 and 22 supported by the lens holder 2 are driven and displaced in the focus direction F or the tracking direction T, and the optical disc is passed through the first and second objective lenses 21 and 22. Tracking control is performed so that the light beam irradiated onto the optical disc 102 is controlled so as to be focused on the signal recording surface of the optical disc 102, and the optical beam is controlled so as to follow the recording track formed on the optical disc 102. Is done.

  As shown in FIGS. 3 and 4, the support 3 has a length along the tracking direction T with respect to the lens holder 2 and a height along the focus direction F.

  Arm support portions 31 that support the support arms 6a, 6b, and 6c and the support arms 6d, 6e, and 6f are provided on both side surfaces of the support 3 that are spaced apart in the tracking direction T, with an interval in the focus direction F, respectively. Yes. A printed wiring board (not shown) is attached to the back side of the support 3. The printed circuit board is supplied with a driving current for focusing and a driving current for tracking from the control circuit unit 109.

  The arm support portions 24 on both sides in the tracking direction T of the lens holder 2 and the arm support portions 31 on both sides in the tracking direction T of the support body 3 are connected by one and the other support arms 6a to 6f, respectively. . As shown in FIGS. 3 to 5, the one and the other support arms 6 a to 6 f are provided in parallel to each other at an interval in the focus direction T, and the lens holder 2 is placed in the focus direction F with respect to the support 3. It is supported so as to be movable in the tracking direction T. Each of the support arms 6a to 6f is made of a linear member having conductivity and elasticity.

  Further, in the objective lens driving device 7 of the optical pickup 1, each of these support arms 6a to 6f supplies a driving current supplied to the focus coils 12a to 12d and the tracking coils 11a and 11b by a driving current determined by the DSP 60 described later. Functions as a means. Here, each of the support arms 6a to 6f serving as the drive current supply means has focus coils 12a and 12b (hereinafter referred to as "front focus") provided on the side surface on the tip side which is one side surface of the lens holder 2 among the focus coils. Coil 12a, 12b ") and focus coils 12c, 12d (hereinafter referred to as" rear focus coils 12c, 12d ") provided on the side surface on the base end side, which is the other side surface of the lens holder 2. ) And independently supply different driving currents, and supply tracking driving currents to the tracking coils 11a and 11b.

  That is, the support arms 6a and 6d have their end portions on the lens holder 2 side connected to connection terminals provided on the focus coils 12a and 12b by soldering or the like, and the end portions on the support body 3 side are printed circuit boards. Are connected to the conductive pattern provided on the substrate. As a result, the drive current for focus from the control circuit unit 109 is supplied to the focus coils 12a and 12b via the support arms 6a and 6d.

  The support arms 6b and 6e have their lens holder 2 side ends connected to connection terminals provided on the focus coils 12c and 12d by soldering, and the support 3 side ends are printed wiring boards. Are connected to the conductive pattern provided on the substrate. As a result, the drive current for focus from the control circuit unit 109 is supplied to the focus coils 12c and 12d via the support arms 6b and 6e.

  Further, the support arms 6c and 6f have their end portions on the lens holder 2 side connected to connection terminals provided on the tracking coils 11a and 11b by soldering or the like, and the end portions on the support body 3 side are printed circuit boards. Are connected to the conductive pattern provided on the substrate. Thus, the tracking drive current from the control circuit unit 109 is supplied to the tracking coils 11a and 11b via the support arms 6c and 6f.

  Here, the six support arms 6a to 6f are provided so as to function as an elastic support member that movably supports the lens holder 2 and function as drive current supply means. However, the number of support arms is as follows. The present invention is not limited to this, and other drive current supply means such as a power supply line may be provided.

  The front focus coils 12a and 12b provided on one side surface of the lens holder 2 in the tangential direction Tz and the rear focus coils 12c and 12d provided on the other side surface are respectively focused on the lens holder 2. A drive current determined according to the position in the direction F and the tracking direction T is supplied.

  Here, the DSP 60 provided in the control circuit unit 109 that determines the drive current supplied to the front focus coils 12a and 12b and the rear focus coils 12c and 12d will be described with reference to FIG.

  The DSP 60 includes a first control calculation unit 63 that calculates the focus drive current Fd based on the focus error signal FE supplied via the matrix amplifier 61 provided in the signal processing unit 120, and the matrix amplifier 61. And a second control calculation unit 64 that calculates the tracking drive current Td based on the supplied tracking error signal TE. The matrix amplifier 61 uses a focus error signal FE, a tracking error signal TE, and the like based on the amount of light received by the optical detector 23 provided in the optical pickup 1 from the reflected light beam reflected from the signal recording surface of the optical disk 102. The various detection signals are detected.

  The DSP 60 also includes a focus position calculation unit 65 that calculates the focus position z of the lens holder 2 from the focus drive current Fd calculated by the first control calculation unit 63 and a tracking drive current calculated by the second control calculation unit 64. Based on the tracking position calculation unit 66 that calculates the tracking position y of the lens holder 2 from Td, and the focus position and tracking position of the lens holder 2 calculated by the focus position calculation unit 65 and the tracking position calculation unit 66, the front focus A focus differential coefficient calculation unit 67 that determines a coefficient K (z, y) for determining a drive current to be supplied to the coils 12a and 12b and the rear focus coils 12c and 12d.

  Here, z indicates the position of the lens holder 2 in the focus direction F, y indicates the position of the lens holder 2 in the tracking direction T, and K (z, y) indicates the lens. 4 shows differential coefficients for determining the drive current for focus supplied to the front and rear focus coils when the holder 2 is in the positions of z and y.

  The coefficient K (z, y) determined by the focus operation coefficient calculator 67 cancels rolling Yro caused by a thrust shift between the front focus coils 12a and 12b and the rear focus coils 12c and 12d by applying a drive current. It is set to be.

The focus operation coefficient calculation unit 67 calculates the coefficient K (z, y), and calculates the following expression (1) based on the coefficient K (z, y) and the supplied focus drive current Fd. The drive current Iff for the front focus coil is supplied to the front focus coils 12a and 12b via the drive amplification circuit 73 described later, and the drive current Ifr for the rear focus coil calculated by the following equation (2) is described later. Is supplied to the rear focus coils 12c and 12d via the drive amplifier circuit 72.
If = K (z, y) × Fd (1)
Ifr = {1−K (z, y)} × Fd (2)

  The coefficient K (z, y) determined by the focus operation coefficient calculator 67 is determined based on the focus position z and tracking position y of the lens holder 2. Specifically, the focus position and tracking position obtained by calculating the thrust deviation of the focus coils 12a to 12d formed from the positions of the coils 12a to 12d and the magnets 13 and 14 in advance by simulation or the like are calculated. Select by (z, y). The coefficient K (z, y) is set in the range of about 0.4 to 0.6.

  In this example, the optimal coefficient corresponding to the position of the lens holder 2 is calculated, but the coefficient calculated by experiment may be used. When the coefficient K (z, y) is experimentally obtained, the transfer function from the focus drive current Fd to the focus error signal or the displacement of the lens holder 2 in the focus direction F is measured. Adjustment can be made by looking at the gain and phase of the Yro resonance frequency of the measurement result.

  In this transfer function, as shown in FIG. 8, when Yro cannot be canceled, the gain and phase are disturbed as indicated by broken lines L11 and L12 or alternate long and short dash lines L21 and L22 in the figure. Here, when K is changed, the phase of rolling Yro changes from plus (+) to minus (-) or vice versa, so the K (z, y) value is changed while looking around the phase of rolling Yro. What is necessary is just to set to an appropriate value and to have a characteristic as shown by the solid lines L31 and L32. Further, this K changes according to the focus stroke amount (z) and the tracking stroke amount (y). Therefore, it is desirable to calculate K (z, y) for each of the focus stroke position z and the tracking stroke position y.

  Here, when the coefficient K (z, y) is calculated experimentally, not only the thrust displacement of the focus coils 12a to 12d that changes according to the position of the lens holder 2, but also the displacement of the focus coils 12a to 12d. And the like, and deviation in thrust due to these coils caused by manufacturing errors such as thickness differences and winding disturbances, and mass imbalance due to manufacturing errors of various parts, that is, driving thrust of the focus coils 12a to 12d Rolling Yro due to the thrust shift of the front and rear focus coils 12a to 12d including the rotational force around the axis in the tracking direction T generated by the shift between the center of the lens holder 2 and the center of gravity of the lens holder 2 can be suppressed.

  In other words, the front focus coils 12a and 12b and the rear focus coils 12c and 12d have a difference in driving force due to the influence of the magnetic field by the magnet on the front and rear coils that change according to the position of the lens holder, and the arrangement of the focus coils. The difference between the driving force of the front and rear coils due to error and manufacturing error, or the rotational force around the axis in the tracking direction generated by the deviation between the center of driving thrust of each coil and the center of gravity of the lens holder, or any of these Rolling Yro can be suppressed by supplying a drive current determined so as to cancel a plurality of factors.

  Further, the control circuit unit 109 is provided with first to third drive amplifier circuits 71, 72, and 73 that amplify each drive current determined and adjusted by the DSP 60 and supply the drive current to each coil. The first drive amplifier circuit 71 amplifies the tracking drive current Td supplied from the second control operation unit 64 and supplies the amplified tracking drive current Td to the tracking coils 11a and 11b. The second amplifier circuit 72 amplifies the drive current Ifr calculated by the focus differential coefficient calculator 67 and supplies the amplified drive current Ifr to the rear focus coils 12c and 12d. The third amplifier circuit 73 amplifies the drive current Iff calculated by the focus differential coefficient calculator 67 and supplies the amplified drive current Iff to the front focus coils 12a and 12b.

  As described above, the drive current determined according to the position of the lens holder 2 is independently supplied to the front focus coils 12a and 12b and the rear focus coils 12c and 12d. It is possible to suppress rolling Yro that occurs due to a difference in driving force between 12b and the rear focus coils 12c and 12d.

  In the objective lens driving device 7 of the optical pickup 1, the lens holder 2 to which the first and second objective lenses 21 and 22 are attached has the first and second objectives in the extending direction of the support arms 6 a to 6 f. Both sides of the intermediate portion between the optical axes of the lenses 21 and 22 are supported by 6a to 6f. That is, the lens holder 2 is configured to fix at least the tip ends of the support arms 6a to 6f to the arm support portions 24 provided on both sides of the intermediate portion between the optical axes of the first and second objective lenses 21 and 22. It is supported so as to be displaceable in the biaxial direction of the focus direction F and the tracking direction T.

  It should be noted that the positions supported by the tip portions of the support arms 6a to 6f of the lens holder 2 are preferably located on both sides of the center of gravity of the lens holder 2 to which the tracking coils 11a and 11b and the focus coils 12a to 12d are attached. By supporting such a position, the first and second objective lenses 21 and 22 can be stably displaced in the focus direction F and the tracking direction T without causing twist or the like.

  The optical pickup 1 includes an elastic support member 4 that supports the lens holder 2 via a pair of left and right support arms 6 a to 6 f so as to be tiltable with respect to the base 8, and an elastic support member 4. Drive means 5 for tilting the support body 3 supported so as to be tiltable in a tilt direction, which is a direction around an axis about the tangential direction Tz, according to the tilt of the optical disk 102.

  The elastic support member 4 is a pair of plate-like leg pieces 41 provided so as to be inclined so as to increase the distance from one end side supporting the support body 3 toward the other end side fixed to the base 8. , 41, and the leg pieces 41, 41 can tilt the support 3 with respect to the base 8 in a tilt direction (so-called radial tilt direction) that is a direction around an axis about the tangential direction Tz. It is something to support.

  In the elastic support member 4, one end side of the pair of leg pieces 41, 41 is attached to the support body 3 via a support attachment member 44, and the other end side is attached to the base 8 via a base attachment member 45. The elastic support member 4 is thus fixed to the support 3 and the base 8 by the support mounting member 44 and the base mounting member 45, and supports the support 3 so as to be tiltable with respect to the base 8. Here, the elastic support member 4 and the base attachment member 45 are integrally fixed by insert molding or insertion and being fixed by adhesion or the like.

  The drive means 5 includes a tilt coil 51 attached to the lower surface of the support 3 and a tilt dipole magnetized magnet 52 attached to the base 8 so as to face the coil 51. The dipole magnetized magnet 52 is formed in a flat plate shape and is fixed on the base 8 with an adhesive or the like.

  The elastic support member 4 is integrated with the tilt coil 51 by inserting a support attachment piece (not shown) into the support attachment member 44 to which the tilt coil 51 is joined, and the support attachment piece is attached to the support 3. It is fixed to the support body 3 by being joined to the lower surface side and screwed with a fixing screw. The elastic support member 4 is fixed by placing the support 3 on a support mounting piece, and the base mounting member 45 is fixed to the base 8 so that the support 3 can be tilted with respect to the base 8. To support.

  The elastic support member 4 and the above-described support 3 and support arms 6a to 6f function as a displacement support mechanism that supports the lens holder 2 so as to be movable in the focus direction F and the tracking direction T.

  As shown in FIGS. 3 and 4, the dipole magnetized magnet 52 has N poles with the tangential direction Tz perpendicular to the focus direction F and the tracking direction T of the first and second objective lenses 21 and 22 as polarization lines. And the S pole are fixed. In addition, the elastic support member 4 is fixed so that a bent portion that is a connecting portion between each leg piece 41 and the support attachment piece is parallel to the tangential direction Tz.

  By the way, as shown in FIG. 3 and FIG. 4, the pair of leg pieces 41, 41 constituting the elastic support member 4 are provided so as to be inclined so that the distance increases from the support attachment piece side toward the base attachment member 45 side. It has been. The pair of leg pieces 41, 41 inclined to each other has a height of the center of gravity of the objective lenses 21, 22 at the same height as the intersection of the virtual lines extending toward the support 3 supported on the support attachment piece. Are formed so as to substantially match. Therefore, the elastic support member 4 is formed in a trapezoid shape as a whole.

  The dipole magnetized magnet 52 is fixed on the base 8 so as to face the coil 51 between the pair of leg pieces 41 and 41.

  When a drive current is supplied to the coil 51 for tilting, a force that moves the coil 51 with respect to the dipole magnetized magnet 52 by the action of the current flowing through the coil 51 and the magnetic field of the dipole magnetized magnet 52. That is, a force for driving the elastic support member 4 and the support 3 supported by the base 8 is generated. The elastic support member 4 is formed of an elastic member such as a leaf spring, has a pair of non-parallel leg pieces 41 and 41, and is supported by the elastic support member 4 having a trapezoidal shape as a whole. When it is received, its posture is changed following the shape of the elastic support member 4.

  By the way, the elastic support member 4 has a predetermined width so as to have rigidity against torsion. The elastic support member 4 has a support attachment piece fixed to the support 3 and an end portion of each leg piece 41 is fixed to the base 8 via the base attachment member 45 so that it receives a driving force. Each leg piece 41, 41 can be elastically deformed like a bow. Further, the bent portion that becomes the connecting portion between the leg pieces 41 and 41 and the support attachment piece can also be elastically deformed.

  Next, the operation of the optical pickup 1 provided with the driving means 5 for driving the support 3 as described above will be described.

  The optical pickup 1 is in a neutral state without deformation of the elastic support member 4 when no power is supplied to the coil 51 of the driving means 5. At this time, the shape and the like of the elastic support member 4 are set so that the first and second objective lenses 21 and 22 supported by the lens holder 2 are horizontal.

  In this state, when a drive current is supplied to the coil 51, the current flows through the coil 51 in the magnetic field of the two-pole magnetized magnet 52, so that the support 3 is in the extending direction of the two-pole magnetized magnet 52. A driving force is generated along the tracking direction T in a substantially horizontal direction. Since the support 3 is supported by a trapezoidal elastic support member 4 having a pair of non-parallel leg pieces 41, 41, the posture of the support 3 becomes the shape of the elastic support member 4 when receiving a driving force. It is controlled by copying.

  That is, when a force for driving the support 3 in a substantially horizontal direction is applied, one leg piece 41 of the elastic support member 4 is elastically deformed in a direction in which an angle with respect to the plane of the base 8 becomes smaller, and the other leg piece 41 is 8 is elastically deformed in a direction in which the angle with respect to the plane is increased. Thereby, the support body 3 inclines in the tilt direction that is the direction around the axis of the tangential direction Tz.

  Since the support body 3 supports the lens holder 2 with the six support arms 6a to 6f, when the support body 3 is tilted, the lens holder 2 is tilted. Thus, according to a predetermined control signal By supplying the drive current to the coil 51, the tilt angle is controlled so that the optical axes of the first and second objective lenses 21 and 22 supported by the lens holder 2 are tilted in accordance with the warp of the optical disk. be able to. The direction of inclination of the support 3 is switched by the direction of the drive current supplied to the coil 51. Further, the inclination angle of the support 3 can be adjusted to a predetermined angle by the drive current voltage value supplied to the coil 51.

  As described above, the driving unit 5 can apply a driving force for tilting the support 3 in the tilt direction to the support 3 by passing a drive current through the coil 51 for tilting, and is supported by the support 3. The lens holder 2 and the objective lenses 21 and 22 can be tilted. Therefore, the objective lenses 21 and 22 can be tilted according to the warp of the optical disk.

  As described above, if the driving means 5 for driving the support 3 is provided and the lens holder 2 is inclined, the amount corresponding to the warp of each optical disk can be provided by providing the means for detecting the inclination of the optical disk. Thus, the first and second objective lenses 21 and 22 can be tilted so that the optical axes of the first and second objective lenses 21 and 22 are perpendicular to the surface of the optical disc. Thereby, the shape of the light spot formed by condensing the light beam on the signal recording surface of the optical disc can always be made appropriate. Moreover, the operation | work which adjusts the inclination of the lens holder 2 manually is also unnecessary.

  Next, focus control and tracking control of the lens holder 2 will be described. When a drive current corresponding to the focus control signal generated from the reproduction signal is supplied to the focus coils 12a to 12d, the current flowing through the focus coils 12a to 12d, the yoke 18 and the yoke pieces 18a and 18b, and the yoke pieces 18a and 18a, The force generated by the action of the magnetic field formed by the magnets 13 and 14 supported by 18b causes the lens holder 2 to move in the optical axis direction of the first and second objective lenses 21 and 22 according to the direction of the drive current. A force in the direction of ascending or descending is generated in parallel. Since the lens holder 2 is supported by one end of the six support arms 6a to 6f, the lens holder 2 maintains a parallel posture with respect to the optical disk 102 rotated by the spindle motor 103 when receiving a force in the up-and-down direction. Move up and down. Thereby, the objective lenses 21 and 22 are focus-controlled in the direction along the optical axis, and the light spot from the objective lenses 21 and 22 is focused on the track of the optical disc.

  When a drive current corresponding to the tracking control signal generated from the reproduction signal is supplied to the tracking coils 11a and 11b, the current flowing through the coils 11a and 11b, the yoke 18 and the yoke pieces 18a and 18b, and the yoke pieces The force generated by the action of the magnetic field formed by the magnets 13 and 14 supported by the magnets 18a and 18b causes the lens holder 2 to rotate in the inner circumferential direction of the optical disk 102 rotated by the spindle motor 103 according to the direction of the current. Alternatively, a force for moving the optical disk 102 in the outer peripheral direction is generated. Since the lens holder 2 is supported by one end of the six support arms 6a to 6f, when receiving a force in a direction moving in a direction parallel to the plane of the optical disc 102, the lens holder 2 of the recording track formed on the optical disc 102 is obtained. Moves and displaces in a direction almost parallel to the normal direction. As a result, tracking control is performed in which the first and second objective lenses 21 and 22 are controlled to move in the radial direction of the optical disc 102, and the light beams emitted from the first and second objective lenses 21 and 22 are obtained as desired. The recording track can be traced.

  The objective lens driving device 7 configured as described above and the optical pickup 1 using the same include the focus coils 12a to 12d, the tracking coils 11a and 11b, and the magnets 13 and 14, thereby elastically supporting the support arms 6a to 6f. By displacing, the objective lenses 21 and 22 held by the lens holder 2 can be driven and displaced in the focus direction F and the tracking direction T.

  Further, the objective lens driving device 7 and the optical pickup 1 are held by the support 3 and the lens holder 2 by elastically displacing the elastic support member 4 by including the tilt coil 51 and the dipole magnetized magnet 52. The objective lenses 21 and 22 can be driven and displaced in a tilt direction that is a direction around an axis with the tangential direction Tz as an axis.

  In addition, the objective lens driving device 7 and the optical pickup 1 can not only realize power saving, but the optical disk device using the optical pickup 1 that can stably drive and control the objective lenses 21 and 22 with a small driving current. The objective lenses 21 and 22 can be accurately driven and displaced in accordance with the focus error signal, tracking error signal, and tilt control signal, and information signal recording or reproduction characteristics can be improved.

  By the way, in the optical pickup 1, the rolling Xro generated around the axis about the tangential direction Tz of the lens holder 2, the rolling Yro generated around the axis about the tracking direction T, and the focus direction F as the axes. When unnecessary resonance such as rolling Zro occurs in the direction around the axis as described above, degradation of servo characteristics becomes a problem.

  As one of the factors causing this unnecessary resonance, as shown in FIGS. 15 and 16, the focus coil and the tracking coil provided on one side surface and the other side surface of the lens holder 2 in the tangential direction Tz, When there is a difference in distance from the magnets facing each other, a difference in driving thrust by the front and rear focus coils occurs, and rolling Yro around the axis in the tracking direction T occurs. A difference in driving thrust due to the tracking coil occurs, and rolling Zro around the axis in the focus direction F occurs.

  Further, as a cause of unnecessary resonance, when the lens holder 2 is driven in the focus direction F, the lens holder 2 is provided in the lens holder 2 by moving in an arc shape as shown in FIG. The gap g12, that is, the gap between the focus coils 12a, 12b and the tracking coil 11a and the tip side magnet 13 (hereinafter also referred to as “front magnet 13”) far from the support 3 is widened, and the focus coil 12c. 12d and the tracking coil 11b and the gap g22 between the proximal end side magnet 14 (hereinafter also referred to as “rear magnet 14”) closer to the support body 3, that is, the interval is narrowed. . In FIG. 9, a state indicated by a broken line indicates a state in which the lens holder 2 is not driven in the focus direction F, and a gap between the front magnet 13 and the front focus coils 12a and 12b and the tracking coil 11a in this state. It is assumed that g11 is equal to the gap g21 between the rear magnet 14 and the rear focus coils 12c and 12d and the tracking coil 11b. 9 indicates the center of gravity of the lens holder 2.

  That is, for example, when the distance between the focus coils 12a and 12b and the magnet 13 facing the focus coils 12a and 12b is increased, the magnetic field strength with respect to each of the coils 12a and 12b is reduced, and the focus coils 12c and 12b By changing the distance between 12d and the magnet 14 opposed thereto in the direction of narrowing, the strength of the magnetic field with respect to each of these coils 12c and 12d increases, and the driving thrust by the front focus coils 12a and 12b decreases. As a result, the driving thrust by the rear focus coils 12c and 12d increases, the balance between the front and rear driving thrusts is lost, and the rotational force f1 is generated, which may cause unnecessary resonance such as rolling Yro.

  Further, as a cause of unnecessary resonance, when the lens holder 2 is driven in the tracking direction T, the lens holder 2 is provided in the lens holder 2 by moving in an arc shape as shown in FIG. The gap g13 between the focus coils 12a and 12b and the tracking coil 11a and the front magnet 13 on the side far from the support 3 is widened, and the focus coils 12c and 12d and the tracking coil 11b and the side close to the support 3 are rearward. For example, the gap g23 with the side magnet 14 is narrowed. In FIG. 10, a state indicated by a broken line indicates a state in which the lens holder 2 is not driven in the tracking direction T. In this state, the front magnet 13 and the front focus coils 12a and 12b and the tracking coil 11a It is assumed that the gap g11 is equal to the gap g21 between the rear magnet 14 and the rear focus coils 12c and 12d and the tracking coil 11b. 10 indicates the center of gravity of the lens holder 2.

  That is, for example, when the distance between the tracking coil 11a and the magnet 13 facing the tracking coil 11a is changed in the direction of increasing, the magnetic field strength with respect to the tracking coil 11a is reduced, and the tracking coil 11b and the magnet facing the magnet 14, the magnetic field strength with respect to the tracking coil 11 b increases, the driving thrust by the front coil 11 a decreases, the driving thrust by the rear coil 11 b increases, There is a possibility that the driving thrust is out of balance and the rotational force f2 is generated, and unnecessary resonance such as rolling Zro occurs.

  In the optical pickup 1, the focus coils 12a and 12b provided on one side surface of the lens holder 2 and the focus coils 12c and 12d provided on the other side surface respectively have a focus direction and a tracking direction of the lens holder 2. A drive current determined according to the position of the lens holder 2 is supplied, the difference in drive thrust generated by the influence of the magnetic field by the magnets 13 and 14 is canceled according to the position of the lens holder 2, and the occurrence of rolling Yro is prevented.

  Specifically, when the lens holder 2 is driven in the state shown in FIG. 9, the coefficient K (z, y) corresponding to the focus position is calculated by the focus differential coefficient calculation unit 67. , A drive current Iff according to the coefficient K (z, y) is supplied to the front focus coils 12a and 12b. Similarly, a drive current Ifr according to the coefficient K (z, y) is supplied to the rear focus coils 12c and 12d. Supplied. Here, at the position shown in FIG. 9, when the coefficient K (z, y) is 0.5 or more, the drive current supplied to the front focus coils 12a and 12b is changed to the rear focus coils 12c and 12d. By making it larger than the drive current supplied to, the front and rear drive thrusts are made equal.

  The optical pickup 1 to which the present invention is applied includes a focus coil 12a, 12b provided on one side surface of the lens holder 2 and a focus coil 12c, 12d provided on the other side surface. By independently supplying a driving current determined according to the position (z, y) in the tracking direction, the driving thrust by the focus coils 12a and 12b provided on one side surface and the other side surface are provided. It is possible to prevent a difference from occurring in the driving thrust by the focus coils 12c and 12d, and to suppress unnecessary resonance due to the rolling Yro generated by the difference in the driving thrust, thereby obtaining high servo stability. That is, the optical pickup 1 to which the present invention is applied can obtain a good servo characteristic without providing a complicated adjustment process, and can perform good recording and / or reproduction of an information signal with respect to an optical disc. It is possible to improve the vibration resistance characteristics by suppressing the vibration mode excitation and to shorten the seek time.

  In the optical pickup 1 described above, the focus position calculation unit 65 calculates the focus position z based on the focus drive current Fd, and the tracking position calculation unit 66 calculates the tracking position y based on the tracking drive current Td. However, the present invention is not limited to this, and the focus position z and tracking position y of the lens holder 2 may be calculated by a measuring unit such as a sensor, and the signal from the detector 23 is processed. The tracking position y or the like may be calculated based on the obtained center error signal or the like.

  Further, the present invention is not limited to the optical pickup having the driving means 5 including the coil 51 and the magnet 52 independently for tilting as described above, but only for tilting from the viewpoint of simplification of the configuration and miniaturization of the apparatus. Of the plurality of focus coils, for example, a so-called differential having a configuration that drives in the tilt direction by providing a difference in the driving force of the focus coils arranged in the tracking direction T, for example. The present invention may be applied to a tilt type optical pickup.

  When the present invention is applied to a differential tilt optical pickup, a DSP 80 as shown in FIG. 11 is used to enable a tilt operation using a plurality of focus coils 12a to 12d and to be provided at the front and rear. Further, it is possible to suppress the rolling Yro generated due to the difference in driving force of the focus coil.

  The DSP 80 includes a first control unit 63, a second control unit 64, a focus position calculation unit 65, a tracking position calculation unit 66, and a focus differential coefficient calculation unit 67, and the lens holder 2 similarly to the DSP 60 described above. Tilt angle target for generating a tilt drive current (tilt signal) as a tilt component for tilting the lens so as to have a predetermined tilt angle (an angle in the tilt direction that is a direction around the axis about the tangential direction Tz) A value generation unit 81. The tilt angle target value generation unit 81 generates a drive current for tilt for obtaining a driving force in a desired tilt direction based on the jitter amount.

  The DSP 80 adds a tilt drive current to the drive current Iff calculated by the focus differential coefficient calculation unit 67 to generate the drive current Iff1 and the tilt drive current from the drive current Iff. And a second subtractor 83 that generates the drive current Ifr1 by adding the tilt drive current to the drive current Ifr calculated by the focus differential coefficient calculator 67. An adder 84 and a second subtractor 85 that generates a drive current Ifr2 by subtracting the drive current for tilt from the drive current Ifr.

  In this case, the control circuit unit 109 is provided with first to fifth drive amplifier circuits 71 to 75 that amplify each drive current determined and adjusted by the DSP 60 and supply the drive current to each coil. The first amplifier circuit 71 amplifies the tracking drive current Td supplied from the second control calculation unit 64 and supplies the amplified tracking drive current Td to the tracking coils 11a and 11b. The fifth amplifier circuit 75 amplifies the drive current Iff1 calculated by the first adder 82 and supplies it to the focus coil 12a provided on the front side and one side in the tracking direction T. The fourth amplifier circuit 74 amplifies the drive current Iff2 calculated by the first subtracter 83 and supplies it to the focus coil 12b provided on the front side and the other side in the tracking direction T. The third amplifier circuit 73 amplifies the drive current Ifr1 calculated by the second adder 84 and supplies the amplified drive current Ifr1 to the focus coil 12d provided on the rear side and one side in the tracking direction T. The second amplifier circuit 72 amplifies the drive current Ifr2 calculated by the second subtracter 85 and supplies the amplified drive current Ifr2 to the focus coil 12c provided on the rear side and the other side in the tracking direction T.

  As described above, the focus coil 12a, 12d provided in one of the tracking directions T is supplied with the current added with the tilt component by the tilt signal, and the focus coils 12b, 12c provided in the other of the tracking directions T are tilted. By configuring so that a current obtained by subtracting the tilt component of the signal is supplied, it is possible to operate in the tilt direction using a plurality of focus coils without providing independent tilt coils and magnets.

  Also, when applied to a differential tilt optical pickup, similarly to the optical pickup 1 described above, the front focus coils 12a and 12b and the rear focus coils 12c and 12d are arranged in accordance with the position of the lens holder 2. By supplying the determined drive current independently, the rolling Yro generated by the difference in driving force between the front focus coils 12a and 12b and the rear focus coils 12c and 12d is suppressed, and high servo stability is obtained. be able to.

  In the optical pickup 1 described above, a driving current corresponding to the position of the lens holder 2 is independently supplied to the front focus coils 12a and 12b and the rear focus coils 12c and 12d. For example, the driving current corresponding to the position of the lens holder 2 may be independently supplied to the front tracking coil 11a and the rear tracking coil 11b.

  Next, the tracking coil 11a provided on one side surface and the tracking coil 11b provided on the other side surface are independently supplied with drive currents, and the positions of the lens holder 2 in the focus direction F and the tracking direction T, respectively. An optical pickup 90 that is supplied with a drive current determined in accordance with the above will be described. The optical pickup 90 is common to the optical pickup 1 described above except for the functions of the support arms 6a to 6f as drive current means and the configuration of the DSP. In the following description, common parts are described. Are denoted by common reference numerals and detailed description thereof is omitted.

  In the optical pickup 90, each of the support arms 6a to 6f serving as a drive current supply unit includes a tracking coil 11a (hereinafter referred to as “front-side tracking”) provided on the side surface on the distal end side which is one side surface of the lens holder 2 among the tracking coils. Coil 11a ") and a tracking coil 11b (hereinafter also referred to as" rear tracking coil 11b ") provided on the side surface on the base end side which is the other side surface of the lens holder 2. Different drive currents are supplied, and focus drive currents are supplied to the focus coils 12a to 12d.

  In other words, in the optical pickup 90, the support arms 6a and 6d are connected to the focus coils 12a to 12d, and a focus drive current from the control circuit unit 109 is supplied to the focus coils 12a to 12d via the support arms 6a and 6d. 12d.

  The support arms 6b and 6e are connected to the tracking coil 11a, and the tracking drive current from the control circuit unit 109 is supplied to the tracking coil 11a via the support arms 6b and 6e.

  The support arms 6c and 6f are connected to the tracking coil 11b, and the tracking drive current from the control circuit unit 109 is supplied to the tracking coil 11b via the support arms 6c and 6f.

  A tracking coil 11a (hereinafter also referred to as “front-side tracking coil 11a”) provided on the side surface on the distal end side, which is one side surface of the lens holder 2 provided on one side surface of the lens holder 2 in the tangential direction Tz. ) And the tracking coil 11b (hereinafter also referred to as “rear tracking coil 11b”) provided on the side surface on the base end side which is the other side surface of the lens holder 2, respectively. A driving current determined according to the position of F and the tracking direction T is supplied.

  Here, the DSP 91 provided in the control circuit unit 109 that determines the drive current supplied to the front tracking coil 11a and the rear tracking coil 11b will be described with reference to FIG.

  The DSP 91 is based on the first control calculation unit 63 that calculates the focus drive current Fd based on the focus error signal TE supplied via the matrix amplifier 61 and the tracking error signal FE supplied via the matrix amplifier 61. And a second control calculation unit 64 for calculating the tracking drive current Td.

  The DSP 91 also includes a focus position calculation unit 65 that calculates the focus position z of the lens holder 2 from the focus drive current Fd calculated by the first control calculation unit 63 and a tracking drive current calculated by the second control calculation unit 64. Based on the tracking position calculation unit 66 for calculating the tracking position y of the lens holder 2 from Td, and the focus position and tracking position of the lens holder 2 calculated by the focus position calculation unit 65 and the tracking position calculation unit 66, the front side tracking is performed. A tracking differential coefficient calculation unit 92 that determines a coefficient K ′ (z, y) for determining a drive current to be supplied to the coil 11a and the rear tracking coil 11b is provided.

  Here, z and y are the same as described above, and K ′ (z, y) is for tracking supplied to the front and rear tracking coils when the lens holder 2 is in the positions of z and y. It shows a differential coefficient for determining the drive current.

  The coefficient K ′ (z, y) determined by the tracking operation coefficient calculation unit 92 cancels rolling Zro caused by thrust deviation between the front tracking coil 11a and the rear tracking coil 11b by applying a drive current. Is set.

The tracking operation coefficient calculator 92 calculates the coefficient K ′ (z, y), and based on the coefficient K ′ (z, y) and the supplied tracking drive current Td, the following equation (3) Is supplied to the front tracking coil 11a via the drive amplifier circuit 72, and the drive current Itr for the rear tracking coil calculated by the following equation (4) is supplied to the drive amplifier circuit. 71 to the rear tracking coil 11b.
Itf = K ′ (z, y) × Td (3)
Itr = {1−K ′ (z, y)} × Td (4)

  The coefficient K ′ (z, y) determined by the tracking operation coefficient calculator 92 is determined based on the focus position z and the tracking position y of the lens holder 2. Specifically, the focus position and the tracking position obtained by calculating the thrust deviation of the tracking coils 11a and 11b formed from the positions of the coils 11a and 11b and the magnets 13 and 14 in advance by simulation or the like are calculated. Select by (z, y). The coefficient K ′ (z, y) is set in the range of about 0.4 to 0.6.

  Further, in the same manner as described above, the optimum coefficient corresponding to the position of the lens holder 2 is calculated, but the coefficient calculated by experiment may be used. When the coefficient K ′ (z, y) is experimentally obtained, the transfer function from the tracking drive current Td to the tracking error signal or the displacement of the lens holder 2 in the tracking direction T is measured. Adjustment is possible by looking at the gain and phase of the Zro resonance frequency of the measurement result.

  In this transfer function, as shown in FIG. 13, when Zro cannot be canceled, the gain and phase are disturbed as indicated by broken lines L41 and L42 or one-dot chain lines L51 and L52 in the figure. Here, when K ′ is changed, the phase of the rolling Zro changes from plus (+) to minus (−) or vice versa, so K ′ (z, y) while looking around the phase of the rolling Zro. The value may be set to an appropriate value to have characteristics as indicated by solid lines L61 and L62. Further, the K ′ changes according to the focus stroke amount (z) and the tracking stroke amount (y). Therefore, it is desirable to calculate K ′ (z, y) for each of the focus stroke position z and the tracking stroke position y.

  Here, when the coefficient K ′ (z, y) is calculated experimentally, not only the thrust displacement of the tracking coils 11a and 11b that changes according to the position of the lens holder 2, but also the arrangement of the tracking coils 11a and 11b. Displacement errors such as misalignment, and front and rear thrust deviations caused by these coils due to manufacturing errors such as thickness differences and winding disturbances, and mass imbalance due to manufacturing errors of various components, that is, driving of tracking coils 11a and 11b Rolling Zro due to the thrust shift of the front and rear tracking coils 11a and 11b including the rotational force around the axis in the focus direction F generated by the shift between the center of thrust and the center of gravity of the lens holder 2 can be suppressed.

  In other words, the front tracking coil 11a and the rear tracking coil 11b include a difference in driving force due to the influence of the magnetic field by the magnet with respect to the front and rear coils that change according to the position of the lens holder, an arrangement error and a manufacturing error of the tracking coil. The difference between the driving force of the front and rear coils due to or the rotational force around the axis in the focus direction generated by the deviation between the center of driving thrust of each coil and the center of gravity of the lens holder, or any of these factors Rolling Zro can be suppressed by supplying the drive current determined to cancel.

  When the optical pickup 90 is used, the first drive amplifier circuit 71 amplifies the drive current Itr calculated by the tracking differential coefficient calculation unit 92 and supplies the amplified drive current Itr to the rear tracking coil 11b. The second amplifier circuit 72 amplifies the drive current Itf calculated by the tracking differential coefficient calculation unit 92 and supplies the amplified drive current Itf to the front tracking coil 11a. The third amplifier circuit amplifies the focus drive current Fd supplied from the first control operation unit 63 and supplies the amplified focus drive current Fd to the focus coils 12a to 12d.

  As described above, the driving current determined in accordance with the position of the lens holder 2 is independently supplied to the front tracking coil 11a and the rear tracking coil 11b. It becomes possible to suppress rolling Zro generated due to a difference in driving force with the coil 11b.

  In the optical pickup 90, the tracking coil 11a provided on one side surface of the lens holder 2 and the tracking coil 11b provided on the other side surface respectively correspond to the position of the lens holder 2 in the focus direction and the tracking direction. The drive current determined in this way is supplied, and the difference in drive thrust generated by the influence of the magnetic field by the magnets 13 and 14 is canceled according to the position of the lens holder 2 to prevent the occurrence of rolling Zro.

  Specifically, when the lens holder 2 is driven in a state as shown in FIG. 10, the coefficient K ′ (z, y) corresponding to the tracking position is calculated by the tracking differential coefficient calculation unit 92. Then, the drive current Itf corresponding to the coefficient K ′ (z, y) is supplied to the front tracking coil 11a. Similarly, the drive current Itr corresponding to the coefficient K ′ (z, y) is supplied to the rear tracking coil 11b. Is done. Here, at the position shown in FIG. 10, when the coefficient K ′ (z, y) is 0.5 or more, the drive current supplied to the front tracking coil 11a is supplied to the rear tracking coil 11b. By making the drive current larger than the drive current, the front and rear drive thrusts are made equal.

  The optical pickup 90 to which the present invention is applied includes a tracking coil 11a provided on one side surface of the lens holder 2 and a tracking coil 11b provided on the other side surface. By independently supplying a driving current determined according to (z, y), a driving thrust by the tracking coil 11a provided on one side surface and a driving thrust by the tracking coil 11b provided on the other side surface are provided. Can be prevented, and unnecessary resonance due to the rolling Zro generated by the difference in driving thrust can be suppressed to obtain high servo stability. In other words, the optical pickup 90 to which the present invention is applied can obtain a good servo characteristic without providing a complicated adjustment process, and can perform good recording and / or reproduction of an information signal with respect to an optical disc. It is possible to improve the vibration resistance characteristics by suppressing the vibration mode excitation and to shorten the seek time.

  In the optical pickup 90 described above, the focus position calculator 65 calculates the focus position z based on the focus drive current Fd, and the tracking position calculator 66 calculates the tracking position y based on the tracking drive current Td. However, the present invention is not limited to this, and the focus position z and tracking position y of the lens holder 2 may be calculated by a measuring unit such as a sensor, and the signal from the detector 23 is processed. The tracking position y or the like may be calculated based on the center error signal or the like.

  In the optical pickups 1 and 90 described above, drive currents corresponding to the position of the lens holder 2 are independently supplied to the front coil and the rear coil of the lens holder 2 of the focus coil or tracking coil, respectively. However, the present invention is not limited to this, and the drive current corresponding to the position of the lens holder 2 is independently supplied to the front coil and the rear coil of the lens holder 2 of each of the focus coil and the tracking coil. You may comprise.

  Next, focus coils 12a and 12b provided on one side surface, focus coils 12c and 12d provided on the other side surface, tracking coil 11a provided on one side surface, and provided on the other side surface A description will be given of an optical pickup 95 in which a drive current is supplied independently from the tracking coil 11b and a drive current determined in accordance with the position of the lens holder 2 in the focus direction F and the tracking direction T is supplied. The optical pickup 95 is the same as the optical pickup 1 described above except for a configuration in which other power supply lines are added in addition to the support arms 6a to 6f as a driving current means, and a configuration of the DSP. In the description, common parts are denoted by common reference numerals and detailed description is omitted.

  In the optical pickup 95, the drive current supply means is a tracking coil 11a (hereinafter also referred to as “front-side tracking coil 11a”) provided on the side surface on the distal end side which is one side surface of the lens holder 2 among the tracking coil and the focus coil. ), A tracking coil 11b (hereinafter also referred to as “rear-side tracking coil 11b”) provided on the side surface on the base end side which is the other side surface of the lens holder 2, and one side surface of the lens holder 2. Focus coils 12 a and 12 b (hereinafter also referred to as “front focus coils 12 a and 12 b”) provided on a side surface on a distal end side and provided on a side surface on a base end portion side which is the other side surface of the lens holder 2. Focus coils 12c and 12d (hereinafter also referred to as “rear focus coils 12c and 12d”). It is configured to provide different drive currents independently.

  Here, the six support arms 6a to 6f function as drive current supply means, and other drive current supply means such as a power supply line are provided so that the front tracking coil 11a, the rear tracking coil 11b, and the front focus coil are provided. Drive currents determined in accordance with the positions of the lens holder 2 in the focus direction F and the tracking direction T are supplied to the 12a and 12b and the rear focus coils 12c and 12d, respectively. Note that by adding a support arm, the added support arm may function as a drive current supply unit without newly providing a power supply line or the like.

  Here, the DSP 96 provided in the control circuit unit 109 that determines the drive current supplied to each coil will be described with reference to FIG.

  The DSP 96 is calculated by the first control calculator 63, the second control calculator 64, the focus position calculator 65, the tracking position calculator 66, the focus position calculator 65, and the tracking position calculator 66. Focus for determining a coefficient K (z, y) for determining a drive current to be supplied to the front focus coils 12a and 12b and the rear focus coils 12c and 12d based on the focus position and tracking position of the lens holder 2 Based on the focus position and tracking position of the lens holder 2 calculated by the differential coefficient calculator 67, the focus position calculator 65, and the tracking position calculator 66, the front tracking coil 11a and the rear tracking coil 11b A transistor for determining a coefficient K ′ (z, y) for determining a drive current to be supplied. And a king differential coefficient calculation unit 92.

  When the optical pickup 95 is used, the first drive amplification circuit 71 amplifies the drive current Itr calculated by the tracking differential coefficient calculation unit 92 and supplies the amplified drive current Itr to the rear tracking coil 11b. The second amplifier circuit 72 amplifies the drive current Itf calculated by the tracking differential coefficient calculation unit 92 and supplies the amplified drive current Itf to the front tracking coil 11a. The third amplifier circuit 73 amplifies the drive current Ifr calculated by the focus differential coefficient calculator 67 and supplies the amplified drive current Ifr to the rear focus coils 12c and 12d. The fourth amplifier circuit 74 amplifies the drive current Iff calculated by the focus differential coefficient calculator 67 and supplies it to the front focus coils 12a and 12b.

  As described above, the driving current determined in accordance with the position of the lens holder 2 is independently supplied to the front tracking coil 11a and the rear tracking coil 11b. It becomes possible to suppress rolling Zro generated due to a difference in driving force with the coil 11b. In addition, the drive currents determined according to the position of the lens holder 2 are independently supplied to the front focus coils 12a and 12b and the rear focus coils 12c and 12d, and the front focus coils 12a and 12b, It becomes possible to suppress the rolling Yro generated due to the difference in driving force between the rear focus coils 12c and 12d.

  The optical pickup 95 to which the present invention is applied includes a tracking coil 11a provided on one side surface of the lens holder 2 and a tracking coil 11b provided on the other side surface. By independently supplying a driving current determined according to (z, y), a driving thrust by the tracking coil 11a provided on one side surface and a driving thrust by the tracking coil 11b provided on the other side surface are provided. And the unnecessary resonance due to the rolling Zro caused by the difference in driving thrust is suppressed, and the focus coils 12a and 12b provided on one side surface of the lens holder 2 and the other How to focus the lens holder 2 on the focus coils 12c and 12d provided on the side surface In addition, by independently supplying a driving current determined according to the position (z, y) in the tracking direction, the driving thrust by the focus coils 12a and 12b provided on one side surface and the other side surface are provided. Further, it is possible to prevent a difference from being generated in the driving thrust by the focus coils 12c and 12d, and to suppress unnecessary resonance due to the rolling Yro generated by the difference in the driving thrust. Therefore, the optical pickup 95 to which the present invention is applied can obtain high servo stability by suppressing unnecessary resonance due to rolling Zro and Yro. That is, the optical pickup 95 to which the present invention is applied can obtain a good servo characteristic without providing a complicated adjustment process, and can perform good recording and / or reproduction of an information signal with respect to an optical disc. It is possible to improve the vibration resistance characteristics by suppressing the vibration mode excitation and to shorten the seek time.

  The configuration in which the drive current corresponding to the position of the lens holder 2 is independently supplied to the front coil and the rear coil of the lens holder 2 of the tracking coil described in the above-described optical pickup 95 is shown in FIG. The plurality of focus coils 12a to 12d described with reference to FIG. 5 can be used to perform a tilting operation, and can be configured to be added to a configuration that suppresses rolling caused by a difference in driving thrust between the focus coils provided at the front and rear. . The DSP used in this case may be configured to include a tracking differential coefficient calculation unit 92 in addition to the configuration of the DSP 80 described with reference to FIG. With such a configuration, it is possible to operate in the tilt direction by using a plurality of focus coils, and to suppress unnecessary resonance due to rolling Zro and Tro and to obtain high servo stability.

  The optical disk apparatus 101 using the optical pickups 1, 90, and 95 described above is complicated because rolling can be suppressed by adjusting the driving thrust by the coils provided on one side and the other side of the lens holder 2. Thus, it is possible to obtain good servo characteristics without providing an adjustment step, and to record and / or reproduce information signals with respect to an optical disc.

1 is a block circuit diagram of an optical disc apparatus using an optical pickup to which the present invention is applied. 1 is a perspective view of an optical pickup to which the present invention is applied. It is a perspective view of the objective lens drive device which comprises the optical pickup to which this invention is applied. It is a disassembled perspective view of the lens holder and support body which comprise the optical pick-up to which this invention is applied. It is a perspective view which shows the lens holder and support body which comprise the optical pick-up to which this invention is applied. It is a figure which shows the magnetization pattern of the magnet which comprises the optical pick-up to which this invention is applied, (a) is a top view from the lens holder side of the 1st magnet arrange | positioned at the front end side, (b) These are top views from the lens holder side of the 2nd magnet arrange | positioned at the base end part side. It is a block circuit diagram for demonstrating the structure of DSP which determines the drive current supplied to each coil. It is a figure which shows the frequency characteristic of the objective lens drive device which comprises an optical pick-up. It is a side view which shows the state which driven the lens holder in the focus direction in the optical pick-up to which this invention is applied. It is a side view which shows the state which driven the lens holder in the tracking direction in the optical pick-up to which this invention is applied. 1 is a block circuit diagram for explaining a configuration of a DSP when the present invention is applied to a differential tilt optical pickup. FIG. It is a block circuit diagram for demonstrating the structure of DSP in the other example of the optical pick-up to which this invention is applied. It is a figure which shows the frequency characteristic of the objective lens drive device which comprises the optical pick-up of another example. It is a figure which shows the structure of DSP in the further another example of the optical pick-up to which this invention is applied. It is a side view of the movable part of the objective lens drive device which comprises the conventional optical pick-up. It is a top view of the movable part of the objective lens drive device which comprises the conventional optical pick-up. It is a block circuit diagram for demonstrating the structure of DSP of the conventional optical pick-up.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Optical pick-up, 2 Lens holder, 3 Support body, 4 Elastic support member, 5 Drive means, 6a-6f Support arm, 7 Objective lens drive device, 8 Base, 11a, 11b Tracking coil, 12a-12d Focus coil, 13, 14 magnet, 18 yoke, 21 first objective lens, 22 second objective lens, 41 leg piece, 51 tilt coil, 52 magnet for tilting, 101 optical disc device, 102 optical disc, 103 spindle motor

Claims (5)

An objective lens that focuses the light beam is attached to the signal recording surface of the optical disk that is driven to rotate, and moves in a focus direction parallel to the optical axis of the objective lens and a tracking direction orthogonal to the optical axis direction of the objective lens A lens holder,
A support body disposed with a gap in the tangential direction orthogonal to the focus direction and the tracking direction with respect to the lens holder;
An elastic support member that connects the lens holder and the support, respectively, and supports the lens holder movably in the focus direction and the tracking direction with respect to the support;
A focus coil that is provided on one side surface and the other side surface of the lens holder in the tangential direction and generates a driving force in the focus direction;
A tracking coil provided on one side surface and the other side surface of the lens holder in the tangential direction, each generating a driving force in the tracking direction;
A magnet disposed opposite to the focus coil and the tracking coil provided on the one and other side surfaces;
Drive current supply means for independently supplying drive current to the focus coil provided on the one side surface and the focus coil provided on the other side surface,
A driving current determined according to the position of the lens holder in the focus direction and the tracking direction is supplied to the focus coil provided on the one side surface and the focus coil provided on the other side surface, respectively. Optical pickup to be used.   The focus coil provided on the one side surface and the focus coil provided on the other side surface have the one side surface that changes according to the position of the lens holder in the focus direction and the tracking direction, respectively. The focus coil provided on the one side surface due to the difference in driving force due to the magnetic field by the magnet, the focus coil placement error, and the manufacturing error with respect to the provided focus coil and the focus coil provided on the other side surface And a driving force difference between the focusing coil provided on the other side surface, or a rotational force around the axis of the tracking direction generated by a deviation between the center of the driving thrust of the focusing coil and the center of gravity of the lens holder, Drive current determined to cancel one or more of The optical pickup of claim 1, wherein the. An objective lens that focuses the light beam is attached to the signal recording surface of the optical disk that is driven to rotate, and moves in a focus direction parallel to the optical axis of the objective lens and a tracking direction orthogonal to the optical axis direction of the objective lens A lens holder,
A support body disposed with a gap in the tangential direction orthogonal to the focus direction and the tracking direction with respect to the lens holder;
An elastic support member that connects the lens holder and the support, respectively, and supports the lens holder movably in the focus direction and the tracking direction with respect to the support;
A focus coil that is provided on one side surface and the other side surface of the lens holder in the tangential direction and generates a driving force in the focus direction;
A tracking coil provided on one side surface and the other side surface of the lens holder in the tangential direction, each generating a driving force in the tracking direction;
A magnet disposed opposite to the focus coil and the tracking coil provided on the one and other side surfaces;
Drive current supply means for independently supplying a drive current to the tracking coil provided on the one side surface and the tracking coil provided on the other side surface,
The tracking coil provided on the one side surface and the tracking coil provided on the other side surface are supplied with driving currents determined according to the focus direction and the tracking direction position of the lens holder, respectively. Optical pickup to be used.   The tracking coil provided on the one side surface and the tracking coil provided on the other side surface have the one side surface that changes according to the position of the lens holder in the focus direction and the tracking direction, respectively. A tracking force provided on the one side surface due to a difference in driving force due to the magnetic field by the magnet, a tracking coil placement error, and a manufacturing error between the provided tracking coil and the tracking coil provided on the other side surface Rotational force in the direction of the focus direction generated by the difference in driving force between the coil and the tracking coil provided on the other side, or the shift between the center of the driving thrust of the tracking coil and the center of gravity of the lens holder Determined to negate any one or more of The optical pickup of claim 3, wherein the drive current is supplied. The drive current supply means independently supplies drive current to the focus coil provided on the one side surface and the focus coil provided on the other side surface,
A driving current determined according to the position of the lens holder in the focus direction and the tracking direction is supplied to the focus coil provided on the one side surface and the focus coil provided on the other side surface, respectively. The optical pickup according to claim 3.

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