JPH11120586A - Objective lens drive - Google Patents

Abstract

(57) Abstract: Provided is an objective lens driving device which has high reliability with respect to temperature change and time-dependent change and can ensure servo stability. SOLUTION: A movable body 50 having an objective lens 1, a lens holder 2, and a pair of permanent magnets 3a and 3b magnetized in the same direction, and a base 51 are provided so as to be elastically deformable in a tangential direction K. The metal support plate 9, the plurality of rod-shaped elastic support members 8 a to 8 d that support the movable body 50 so as to be elastically movable in the focusing direction F and the tracking direction T with respect to the metal support plate 9, and control the metal support plate 9. Vibration damping member 11
And the permanent magnets 3a, 3b, the movable body 5
0 in the focusing direction F and the tracking direction T by electromagnetic force generating means 4a, 4b, 6a, 6
b, 7a and 7b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective lens driving apparatus, and more particularly, to an objective lens driving apparatus for an apparatus for optically recording or reproducing information on a disk-shaped recording medium, which is reliable with respect to temperature change and aging change. The present invention relates to a device having high performance and capable of ensuring servo stability.

[0002]

2. Description of the Related Art An objective lens driving apparatus is provided with a device for optically recording or reproducing information on a disk-shaped recording medium (hereinafter referred to as a disk) such as a compact disk or the like in a predetermined radial direction of the disk in parallel with the disk. In order to correct the focusing error due to the vertical movement of the warpage of the disk, the tracking error due to the eccentricity, or the relative inclination between the disk and the objective lens, the objective lens is moved in the optical axis direction when the objective lens is not driven. A direction perpendicular to the disk (hereinafter referred to as a focusing direction), the predetermined radial direction of the disk (hereinafter referred to as a tracking direction), and a tangential direction of the disk in the predetermined radial direction (hereinafter simply referred to as a tangential direction). ), And is driven in three directions of a rotation direction (hereinafter referred to as a tilt direction).

In such an objective lens driving device, a lens holder for holding the objective lens is elastically movable in at least two directions of a focusing direction and a tracking direction. Uses metal wires.

[0004] A supporting mechanism using such a metal wire is as follows.
Originally, it has various resonance modes, and the resonance is amplified by the imbalance of the driving force and the weight of the parts due to the dispersion of the parts, the assembly error, and the like, which may deteriorate the displacement frequency characteristic of the objective lens driving device. .

In order to make the apparatus thinner, the objective lens is
In the type of the lens holder, which is arranged at a position separated in the longitudinal direction of the metal wire from the position where the metal wire is connected to the lens holder, since the position of the objective lens is shifted from the node of the resonance mode, The amplitude at the time of resonance increases, and the displacement frequency characteristics are degraded. In addition, the resonance in the buckling direction of the metal wire that rotates and vibrates the movable body including the objective lens and the lens holder around the tracking direction occurs near the servo gain intersection frequency, and it is difficult to perform stable servo. Met.

Further, in the objective lens driving device capable of driving in the tilt direction, when driven in the focusing direction or the tracking direction simultaneously with the tilt direction, the four metal wires are driven in a twisted state, so that unnecessary resonance occurs. It was easy to occur, and the displacement frequency characteristics were further deteriorated. Moreover,
The diameter, length, etc. of the metal wire are determined by the low-order resonance frequency of the objective lens driving device, and it has been impossible to shift the frequency of only unnecessary resonance caused by the metal wire.

A first prior art example of a thin objective lens driving device capable of suppressing unnecessary resonance is disclosed in Japanese Patent Application Laid-Open No. 4-284106.

According to Japanese Patent Application Laid-Open No. 4-284106,
The objective lens driving device includes a movable unit including a light collecting unit that collects the light beam and irradiates the recording medium with the light, and a holding unit that holds the light collecting unit. Support means for supporting the movable part on the fixed part so as to be movable in the tracking direction, and driving means for displacing the movable part in the focusing direction and the tracking direction, wherein the support means has one end fixed to the movable part at the other end. A plurality of elastic members connected to the elastic member, a bent portion is provided between both ends of the elastic member, and a damper material is provided at least between the elastic member and one of the connection portions. .

According to such a configuration, the bending portion provided on the elastic body and the damper material act to prevent vibration in the focusing direction or the tracking direction and vibration in the elastic body in the longitudinal direction of contraction or torsion. However, the resonance peak can be suppressed.

A second conventional example of a thin objective lens driving device capable of suppressing unnecessary resonance is disclosed in Japanese Patent Application Laid-Open No. 4-31937.

According to Japanese Patent Application Laid-Open No. Hei 4-31937,
The objective lens driving device has a mechanism for driving the objective lens of the device for writing or reading optical information on the disk-shaped recording medium in the tracking direction and the focusing direction, a lens holder for holding the objective lens, and a lens at one end. The rod-like elastic member is supported by a plurality of substantially parallel rod-like elastic members attached to the holder, and the other end of the rod-like elastic member is attached to the fixed member via an elastic member that can be displaced only in the longitudinal direction of the rod-like elastic member. .

According to such a configuration, the resonance frequency that causes the lens holder to rotate and vibrate around the tracking direction depends on the spring constant of the elastic member without changing the low-order resonance frequency of the objective lens driving device. Once determined, it can be kept away from the servo gain intersection, and stable servo can be performed.

[0013]

However, in the first conventional example, since a complicated bent portion is formed by using a rod-shaped plate material as the elastic body, the elastic body is used at the time of assembly or mounting of the damper material. Are easily damaged or distorted. When the elastic body is distorted, when the objective lens is moved, that is, when the elastic body is deformed, the attitude of the objective lens with respect to the disk surface changes, and tilt occurs. As a result, an optical aberration occurs, and the recording / reproducing signal deteriorates.

In the first conventional example, the effect of suppressing resonance can be obtained by attaching a damper material to the bent portion of the elastic body. However, in order to attach the damper material, it is necessary to reduce the adhesiveness. It is necessary to adhere to the bent part of the elastic body by the substance that has it, the damper material is deformed due to ambient temperature change and aging, tilt occurs, or the adhesive force is reduced and the effect of suppressing resonance is deteriorated, etc. However, there is a problem that reliability is low.

In the second conventional example, a printed circuit board is used as an elastic member in order to improve the assemblability. However, since the printed circuit board is made of resin, the characteristics change due to temperature changes and aging. Could be.

Further, the objective lens driving device capable of driving in the tilt direction has the following problem. FIG. 10 is a top view schematically showing the structure of a conventional objective lens driving device that can be driven in the tilt direction. The figure shows a state in which the movable body has been moved to the maximum position in the movable range in the tracking direction, the bobbin is shown in a cross section, and the holding member is shown in a transparent manner. In the figure,
T is the tracking direction, A and B are the tracking directions T
, K indicates a tangential direction. Reference numeral 2 denotes a lens holder having a window 2a at the center. The objective lens 1 and the first lens holder 2 are symmetrically arranged on a symmetric plane 102 passing through the center of gravity 101 of the lens holder 2 and parallel to the focusing direction and the tangential direction K. And a second permanent magnet 3b. First and second permanent magnets 3
a and 3b are arranged along the peripheral surface of the window 2a such that both the pole faces 52a and 52b face the tangential direction K and the directions of magnetization Ha and Hb are different from each other. The lens holder 2 has a base end fixed to the fixed support plate 109 and side surfaces supported by the distal ends of four wire members 8 a to 8 d that can be elastically deformed in the cross-sectional direction. Fixed. Therefore, the movable body 5 composed of the objective lens 1, the lens holder 2, and the permanent magnets 3a, 3b
Numeral 0 is supported by the wire members 8a to 8d so as to be elastically movable with respect to the holding member 10 in the focusing direction (the thickness direction in the drawing) and the tracking direction T. A viscoelastic material storage hole 103 is formed in the holding member 10 so as to allow the respective base ends of the wire members 8a to 8d to pass therethrough, and the viscoelastic material storage hole 103 is filled with a viscoelastic material 104. .
The holding member 10 is fixed to one end of a fixed base 12, and a first bobbin 5 a and a second bobbin 5 b are erected on the other end of the fixed base 12 so as to be aligned in the tracking direction T. I have. The first and second bobbins 5a and 5b have flat opposed yokes 4a and 4b extending in the focusing direction and the tracking direction T, respectively.
The focusing coils 7a, 7b having a winding axis in the focusing direction and the tracking coils 6a, 6b having the winding axis in the tracking direction T are wound around the lens holder 2 in a state where the lens holder 2 is not driven. , Are arranged symmetrically with respect to the symmetry plane 102.

In the conventional objective lens driving device that can be driven in the tilt direction as configured above, the first bobbin 5
The movable body 50 can be driven in the tilt direction R around the tangential direction K by supplying currents having different magnitudes to the focusing coil 7a of FIG. 7a and the focusing coil 7b of the second bobbin 5b, but the magnetic flux is slightly increased. In order to obtain a density, the two permanent magnets 3a, 3b are configured such that their pole faces 52a, 52b have different polarities. However, as the size of the device is reduced, the distance between the two opposing yokes 4a and 4b and the distance between the two permanent magnets 3a and 3b must be reduced. When moved to the maximum position, the magnetic path of the magnetic circuit formed by one permanent magnet and the corresponding yoke is the same as the magnetic path of the magnetic circuit formed by the other permanent magnet and the corresponding yoke. It was joined. That is, as shown in the figure, when the movable body 50 has moved to the maximum in the direction A, the magnetic pole surface 52 facing the corresponding opposing yoke 4a.
The first permanent magnet 3a whose a is an N pole is
a is magnetized so that the end in the B direction of the opposing yoke 4a becomes an N pole. Then, the N pole of the opposing yoke 4a is connected to the magnetic pole surface 5 of the second permanent magnet 3b located at a close position.
This will attract the S pole of 2b. As a result, the movable body 5
In the servo in the tracking direction of 0, the stopper position when the movable body 50 is moved in the direction A is one stable point. Similarly, the stopper position when the movable body 50 is moved in the direction B is another stable point. as a result,
The linearity in the current sensitivity characteristic of the displacement amount is significantly deteriorated, and it has been difficult to secure the servo stability.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and is capable of realizing a stable displacement frequency characteristic by suppressing unnecessary resonance, suitable for thinning, and having a simple structure and a high temperature. It is an object of the present invention to provide a highly reliable objective lens driving device with respect to changes and aging.

Another object of the present invention is to provide an objective lens driving device which can be driven in the tilt direction and can ensure servo stability.

[0020]

The object lens driving device according to the present invention (claim 1) is used by being incorporated in a device for optically recording or reproducing information on a disk-shaped recording medium, and is used for the disk-shaped recording medium. An objective lens having an optical axis at the time of non-driving in a focusing direction that is a direction perpendicular to the lens, a lens holder holding the objective lens, and a movable body having a permanent magnet disposed on the lens holder; and a base, An elastic support plate disposed on the base so as to be elastically deformable in a tangential direction which is a predetermined direction perpendicular to the focusing direction; and the movable body is moved relative to the elastic support plate in the focusing direction.
And a plurality of rod-shaped elastic support members having a distal end fixed to the elastic support plate at the distal end so as to be elastically movable in a tracking direction which is a direction perpendicular to the focusing direction and the tangential direction. An electromagnetic force is applied to the movable body in the focusing direction and the tracking direction by an interaction between a vibration damping member for attenuating the vibration of the elastic support plate and a permanent magnet of the movable body provided on the base. Wherein the elastic support plate is made of metal.

The objective lens driving device according to the present invention (claim 2) is used by being incorporated in an apparatus for optically recording or reproducing information on a disk-shaped recording medium, and is in a direction perpendicular to the disk-shaped recording medium. A movable body having an objective lens having a non-driving optical axis in the focusing direction, a lens holder for holding the objective lens, and two or more permanent magnets provided in the lens holder; a base; and the movable body An elastic member supporting the base so as to be elastically movable in the focusing direction and a tracking direction that is a predetermined direction perpendicular to the focusing direction, and extending on the base in the focusing direction and the tracking direction. And two or more yokes made of a plate-shaped magnetic material disposed in the focusing direction so as to have winding axes in the focusing direction around the two or more yokes. And two or more wound focusing coils; and an electromagnetic force generating means having two or more tracking coils wound around the two or more yokes so as to have a winding axis in the tracking direction. The two or more permanent magnets of the movable body, the two or more yokes and the two or more focusing coils of the electromagnetic force generating means are passed through the center of gravity of the movable body when not driven and in the focusing direction, the focusing direction and the focusing direction. Arranged so as to be substantially symmetrical with respect to a plane parallel to a tangential direction which is a direction perpendicular to the tracking direction, and, by the electromagnetic force generating means, move the movable body by interaction with a permanent magnet of the movable body. It is driven by electromagnetic force in the focusing direction, the tracking direction, and the tilt direction which is a rotation direction around the tangential direction. In the objective lens driving apparatus constructed in two or more permanent magnets of the movable body, those two adjacent in the tracking direction,
Both are magnetized in the same direction.

The objective lens driving device according to the present invention (Claim 3) is used by being incorporated in an apparatus for optically recording or reproducing information on a disk-shaped recording medium, and is in a direction perpendicular to the disk-shaped recording medium. An objective lens having a non-driving optical axis in the focusing direction, a lens holder holding the objective lens, and a movable body having a permanent magnet disposed on the lens holder, a base, and the movable body, For the base,
An elastic member which supports the focusing direction and a tracking direction which is a predetermined direction perpendicular to the focusing direction so as to be elastically movable; and a plate-shaped member arranged on the base so as to extend in the focusing direction and the tracking direction. A yoke made of a magnetic material, a focusing coil wound around the yoke to have a winding axis in the focusing direction, and a tracking coil wound around the yoke to have a winding axis in the tracking direction around the yoke And an electromagnetic force generating means for driving the movable body with an electromagnetic force in the focusing direction and the tracking direction by interaction with the permanent magnet of the movable body. The permanent magnet of the body is located on both sides of the yoke of the electromagnetic force generating means in the thickness direction. The objective lens driving device, wherein each of the pole faces are arranged in a paired manner parallel to oppose to the yoke.

In the objective lens driving device according to the present invention (claim 4), in the objective lens driving device (claim 3), the movable body has two or more pairs of permanent magnets, and the electromagnetic force generating means But the above yoke, focusing coil,
And two or more tracking coils.
At least one pair of permanent magnets, two or more yokes and two or more focusing coils of the electromagnetic force generating means are parallel to a tangential direction passing through the center of gravity of the movable body and perpendicular to the focusing direction and the tracking direction. Arranged so as to be substantially symmetrical with respect to a plane, and the electromagnetic force generating means is configured to drive the movable body with an electromagnetic force also in a rotational direction around the tangential direction. Two or more pairs of permanent magnets are adjacent to each other in the tracking direction.
Are magnetized in the same direction.

[0024] In the objective lens driving device according to the present invention (claim 5), in the objective lens driving device (any one of claims 2 to 4), the elastic member may be attached to the base in the tangential direction. An elastic support plate arranged so as to be deformable,
A plurality of rod-like elastic supports having a distal end fixed to the movable body and a base end fixed to the elastic support plate so as to support the movable body elastically in the focusing direction and the tracking direction with respect to the elastic support plate. And a damping member configured to dampen the elastic support plate, wherein the elastic support plate is
It is assumed to be made of metal.

[0025] In the objective lens driving device according to the present invention (claim 6), in the objective lens driving device (claim 1 or 5), the elastic support plate may be formed of a metal plate elastically deformable in a thickness direction. The damping member is made of a damping material obtained by sticking a plate-shaped viscoelastic member as a damping member.

In the objective lens driving device according to the present invention (claim 7), in the objective lens driving device (one of claims 1, 5 and 6), the base is provided with the elastic support plate. Resin holding member and a metal fixing base on which the electromagnetic force generating means is disposed, and the fixing base is integrated with the elastic support plate and the holding member by insert molding. It is made to be formed in an objective manner.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is an exploded perspective view showing the configuration of the objective lens driving device according to the first embodiment of the present invention, and FIG. 2 is a top view schematically showing the configuration of the objective lens driving device of FIG. 1 and 2 show a state in which the movable body is not driven, and FIG. 2 shows the bobbin in a cross section and shows the holding member in a transparent manner.

In these figures, 16 is a disk, F
Indicates a focusing direction, T indicates a tracking direction, K indicates a tangential direction, and R indicates a tilt direction. The focusing direction F, the tracking direction T, and the tangential direction K are orthogonal to each other, and each of the directions is in three-dimensional orthogonal coordinates. It has a direction corresponding to the direction of each coordinate axis.

Reference numeral 2 denotes a lens holder made of a molded resin. The lens holder 2 has a substantially rectangular window 2a having a long side extending in the tracking direction T at the center thereof. On one side in the tangential direction K, the objective lens 1 is disposed so as to have the optical axis J in the focusing direction F, and on the other side, the first permanent magnet 3a and the second permanent magnet 3b are provided with the window 2a. Are arranged in the tracking direction along the peripheral surface of. Further, the objective lens 1, the first permanent magnet 3a, and the second permanent magnet 3b
Are arranged symmetrically with respect to a symmetry plane 102 which passes through the center of gravity 101 of the lens holder 2 and is parallel to the focusing direction F and the tangential direction K. Further, the first and second permanent magnets 3a and 3b are The magnetic pole surfaces 52a and 52b are arranged so that both of them face the tangential direction K, and the magnetization directions Ha and Hb are the same. Then, the objective lens 1, the lens holder 2, and the first and second permanent magnets 3a,
3b constitutes the movable body 50. The driving center of the first and second permanent magnets 3a and 3b with respect to the movable body 50 is
It is set so as to substantially coincide with the center of gravity 101 of the movable body 50.

Reference numeral 10 denotes a holding member made of a transparent resin. The holding member 10 includes a connecting portion 10c formed so as to extend in parallel with the tracking direction T and in an inverted U-shape in the focusing direction F. It has two rectangular parallelepiped viscoelastic storage portions 10a and 10b formed on both side surfaces of the portion 10c so as to extend in the tangential direction K, and includes the connecting portion 10c and the viscoelastic storage portions 10a and 10b. The stepped concave portions 10d and 10e are formed at both sides of the end surface 10f of the holding member 10 having a constant width in the focusing direction F over the entire length of the holding member 10.

Each of the viscoelastic storage sections 10a and 10b has a cylindrical viscoelastic storage hole 103 penetrating the viscoelastic storage sections 10a and 10b in the tangential direction K, and has a wire member 8a, 8b, 8c and 8d are respectively formed at the same pitch as the stretch pitch. The end face 10f of the holding member 10 and the end face 10f
A metal support plate 9 made of an elastic metal material such as phosphor bronze formed in a shape to cover 0d and 10e is fixed, and the metal support plate 9 is provided at a portion corresponding to the step of the stepped recesses 10d and 10e. Slits 53 are formed in the focusing direction F and in the tracking direction T at the center in the focusing direction F, so that portions of the metal support plate (elastic support plate) 9 that cover the stepped recesses 10d and 10e are viscous. Divided into four movable parts 9a to 9d corresponding to the four viscoelastic material storage holes 103 of the elastic storage parts 10a and 10b,
The four movable parts 9a to 9d are elastically displaceable independently of each other in the tangential direction K.

The movable portions 9a to 9 of the metal support plate 9
four wire members (rod-like elastic support members) that can be elastically deformed in the cross-sectional direction between d and the side of the lens holder 2
8a to 8d are respectively inserted through the viscoelastic storage holes 103 of the holding member 10 and one ends of the movable portions 9a to 9
d, and the other end is fixed to the side of the lens holder 2 by soldering, and is stretched in the tangential direction K in parallel with each other. Here, the four wire members 8 a to 8 d are stretched such that the support center for the movable body 50 substantially coincides with the center of gravity 101 of the movable body 50. Further, as the wire members 8a to 8b, a wire or a rod made of an elastic metal material such as phosphor bronze and having a cross-sectional shape such as a circular, substantially polygonal, or elliptical shape is used.

Each viscoelastic storage hole 103 has a wire member 8
a, 8b, 8c, and 8d are filled with the wire member viscoelastic material 104, and the stepped recesses 10d and 10e are respectively filled with the wire members 8a, 8b, and 8c and 8d.
Movable parts 9a, 9b, and 9 of the metal support plate 9
The viscoelastic material 11 (damping member) for a metal support plate is arranged so as to be in contact with c and 9d.

Reference numeral 12 denotes a metal fixed base, which has a U-shaped plate-shaped main body 12a extending in the tracking direction T and the tangential direction K, and one end in the tangential direction K of the main body 12a. The outer peripheral surface has a joining portion 12a formed in a shape along the inner peripheral surface formed by the connecting portion 10c of the holding member 10 and the viscoelastic storage portions 10 and 10b. The holding member 10 is formed integrally with the fixed base 12 and the metal support plate 9 by insert molding, so that the holding member 10 is connected to the connecting portion 10c and the viscoelastic storage portions 10 and 10b. It is fixed to the fixed base 12 such that the outer peripheral surface of the joint 12a of the fixed base 12 is joined to the formed inner peripheral surface. The fixed base 12 and the holding member 10 constitute a base 51. Therefore, the movable body 50 can be elastically moved in the focusing direction F and the tracking direction T by the four wire members 8a to 8d with respect to the base 51, and the center of gravity 1 of the movable body 50
It is supported rotatably in the tilt direction R about 01. The four wire members 8a to 8d are supported by the metal support plate 9 on the base 51 independently so as to be displaceable in the respective longitudinal directions.

The main body 12a of the fixed base 12 has
The first bobbin 5a and the second bobbin 5b are located in the window 2a of the lens holder 2 and have the tracking direction T
It is erected to line up.

The first and second bobbins 5a and 5b are provided with opposing yokes (electromagnetic force generating means) 4a, made of a flat magnetic material extending in the focusing direction F and the tracking direction T.
4b is formed by resin molding.
The tracking coils (electromagnetic force generating means) 6a and 6b each having a winding axis in the tracking direction T are wound around the periphery of the tracking coil 6b.
Are wound around focusing coils (electromagnetic force generating means) 7a and 7b each having a winding axis in the focusing direction F. The first bobbin 5a and the second bobbin 5b are arranged symmetrically with respect to the symmetry plane 102 of the lens holder 2 in a state where the movable body 50 is not driven.

FIG. 3 is a block diagram showing the configuration of a drive circuit for moving and moving the movable body in the focusing direction and the tilt direction in the objective lens driving device according to the first embodiment. In the figure, reference numeral 13 denotes a tilt detector which detects a relative angle error between a disk and an optical axis of an objective lens to generate a tilt error signal, and 14 denotes a disk and an objective lens which are output from a focusing detector (not shown). An adder 15 adds a focus error signal indicating a distance error between the focus error signal and the tilt error signal, and a subtractor 15 subtracts the tilt error signal from the focus error signal. These tilt detector 13, adder 14, subtractor 15, and focusing detector are shown in FIG.
Are housed in an optical unit (not shown) disposed on the back of the fixed base 12. Here, the tilt detector 13
It is not always necessary to directly detect the relative angle between the disk and the optical axis of the objective lens, and a tilt error signal may be generated based on the detected numerical value related to the tilt amount. In the first embodiment, for example, the tilt detector 13 detects a jitter value of a reproduced signal when data is reproduced from a disk, and outputs a signal that minimizes the detected jitter value as a tilt error signal. I am trying to do it. If tilt detection is performed based on the jitter value in this manner, it is not necessary to supply power to the movable body through a wire member for tilt detection, and thus the metal support plate 9 can be formed in a desired shape.

Next, the operation of the objective lens driving device configured as described above will be described. First, the driving operation of the movable body in the focusing direction will be described with reference to FIGS.
Here, it is assumed that no tilt has occurred.

When the focus error signal is output, the adder 14 and the subtracter 15 input the focus error signal to the focusing coils 7a and 7b, respectively. Then, the focusing direction is established between each magnetic flux passing through the first and second permanent magnets 3a, 3b and the corresponding opposing yokes 4a, 4b, and the current which is a focus error signal flowing through each of the focusing coils 7a, 7b. F is generated, and the generated electromagnetic force is
The movable body 50 is supported by the wire members 8a to 8d, and is moved in the focusing direction F.
Approximately translates. Thus, the movable body 50 is driven in the focusing direction F.

Next, the operation of driving the movable body in the tracking direction T will be described with reference to FIGS.

FIG. 4 is a top view schematically showing the operation of driving the movable body in the tracking direction of the objective lens driving device according to the first embodiment. The figure shows a state in which the movable body has been moved to the maximum position in the movable range in the tracking direction, the bobbins 5a and 5b are shown in a cross section, and the holding member 10 is shown in a transparent manner. In these figures, when a tracking error signal (not shown) is output, the tracking error signal is input to the tracking coils 6a and 6b, and the first and second permanent magnets 3
An electromagnetic force in the tracking direction T is generated between each magnetic flux passing through the a and 3b and the corresponding yokes 4a and 4b corresponding thereto and a current which is a tracking error signal flowing through each of the tracking coils 6a and 6b. The first and second permanent magnets 3a and 3b receive the generated electromagnetic force, and the movable body 50
It is supported by the wire members 8a to 8d and substantially translates in the tracking direction T. Thereby, the movable body 50 is driven in the tracking direction T.

Further, as shown in FIG.
Is the second bobbin 5b in the A direction of the tracking direction T.
Of the focusing coil 7b is the window 2 of the lens holder 2.
a, the first permanent magnet 3a and the second permanent magnet 3b maintain their respective magnetic pole surfaces 52, even when driven to the position in contact with the inner peripheral surface of a, that is, the maximum position in the movable range in the direction A.
The first permanent magnet 3a magnetizes the corresponding opposing yoke 4a such that the end in the B direction of the opposing yoke 4a has the N pole. On the other hand, since the magnetic pole surface 52b of the second permanent magnet 3b located near the N pole of the opposing yoke 4a is an N pole, it is formed by the first permanent magnet 3a and the corresponding opposing yoke 4a. The magnetic path of the magnetic circuit is not coupled to the magnetic path of the magnetic circuit formed by the second permanent magnet 3b and the corresponding yoke 4b. The same applies to the case where the movable body 50 is driven in the B direction of the tracking direction T. Therefore, in the servo in the tracking direction, the spring constant of the wire members 8a to 8d, the distance between the permanent magnet 3a and the opposing yoke 4a, and the distance between the permanent magnet 3b and the opposing yoke 4a.
The number of stable points determined by the spring constant of the magnetic spring between b and b becomes one, and the stability of the servo can be ensured.

Next, the operation of driving the movable body in the tilt direction will be described with reference to FIGS. In these figures, when a relative angle error occurs between the disk 16 and the optical axis J of the objective lens 1, the tilt detector 13 outputs a tilt error signal corresponding to the generated relative angle error. Upon receiving this output, the adder 14 adds the output tilt error signal to the focus error signal, and inputs the added signal to the focusing coil 7a of the first bobbin 5a. On the other hand, upon receiving the output of the tilt error signal, the subtractor 15
The output tilt error signal is subtracted from the focus error signal, and the subtracted signal is input to the focusing coil 7b of the second bobbin 5b. Thereby, the electromagnetic force in the focusing direction F generated by the focusing coil 7a of the first bobbin 5a and the electromagnetic force in the focusing direction F generated by the focusing coil 7b of the second bobbin 5b correspond to the tilt error signal. Differences occur. In response to the electromagnetic force having this difference, a moment corresponding to the tilt error signal acts between the first permanent magnet 3a and the second permanent magnet 3b, and the moment causes the movable body 50 to move to the center of gravity. The disc 16 and the objective lens 1 rotate in the tilt direction R around the center 101.
Is shifted from the optical axis J. In the first embodiment, since the tilt error signal is generated based on the jitter value, the tilt is corrected based on the tilt error signal as described above. Be improved.

Next, the operation of the metal support plate 9 will be described with reference to FIGS. In these figures, the wire member 8a
8d can be elastically deformed in the longitudinal direction of the wire members 8a to 8d. Therefore, the spring constant of the wire members 8a to 8d in the longitudinal direction is And the wire members 8a to 8d are connected in series to form a spring constant, so that the spring structure can be different from the spring structure in the case of the lower-order resonance mode. For this reason,
Irrespective of the resonance frequency in the case of the low-order resonance mode, the frequency shift of the unnecessary resonance in the longitudinal direction of the wire members 8a to 8d becomes possible. In addition, the movable parts 9a to 9
Viscoelastic material 1 for metal support plate arranged so as to be in contact with 9d
1 tends to deform in the tensile direction or the compressive direction, so that a resonance suppression effect with a high damping rate can be obtained. Further, since the elastic support plate is made of metal, the characteristics do not deteriorate due to a change in ambient temperature or a change with time.

In the above description, the tilt detector 13
Detects a jitter value as a tilt detection method. The tilt detection method only needs to detect the relative angle between the disk 16 and the optical axis J of the objective lens 1. For example, a reflection type optical sensor is used. The tilt may be detected by being mounted on the movable body 50. In this case, it is necessary to supply power to the optical sensor through the wire members 8a to 8d or to separately connect a power supply wire to the optical sensor. Further, a part of a light beam for recording and reproduction may be used instead of the light emitting part of the reflection type optical sensor, and a reflection type optical sensor may be provided on the base 51.
In this case, the same effect as above can be obtained,
Further, weight reduction and simplification can be achieved.

In the above description, the direction in which gravity is applied, that is, the attitude of the objective lens driving device is not described. However, the objective lens driving device according to the present invention has the same effect regardless of the direction in which gravity is applied. Can be obtained.

As described above, in the first embodiment, the first and second permanent magnets 3a and 3b are
Opposing yokes 4a, 4b, tracking coils 6a, 6b, and focusing coil 7, which are electromagnetic force generating means.
a and 7b are provided on a base 51, and the base ends of the wire members 8a to 8d supporting the movable body 50 are supported by a metal support plate 9 as an elastic support plate so as to be elastically movable in a tangential direction K. In the objective lens driving device configured to attenuate the vibration of the metal support plate 9 by the support plate viscoelastic material 11, the metal support plate 9 as the elastic support plate is made of metal, so that the ambient temperature change or aging change As a result, the characteristics are not degraded, and a highly reliable resonance suppressing effect can be obtained. Further, the first and second permanent magnets 3a,
3b, the movable body 50
It is not necessary to supply power through the wire members 8A to 8d in order to drive the wire members. Therefore, there is no need to electrically insulate the wire members 8a to 8d with the metal support plate 9 as an elastic support plate. Even if the metal support plate 9 is made of metal, the structure of the metal support plate 9 is
An optimal structure for suppressing the resonance of 8d can be obtained. In addition, since the shapes of the components such as the wire members 8a to 8d and the metal support plate 9 and the assembling configuration are simple, breakage of components at the time of assembling or distortion of the wire members 8a to 8d are unlikely to occur, and stable assembling is possible. Become.

In the first embodiment, two permanent magnets 3a and 3b, two opposed yokes 4a and 4b, and two focusing coils 7a and 7b are provided.
The movable body 50 is arranged so as to be symmetrical with respect to a symmetry plane 102 which passes through the center of gravity 101 of the zero point and is parallel to the focusing direction F and the tangential direction K. In the objective lens driving device configured to be driven, the movable body 50
Since the two permanent magnets 3a and 3b are magnetized (Ha, Hb) in the same direction, the movable body 50
Is moved in the tracking direction T to a position where one of the two permanent magnets 3a and 3b is close to the yoke corresponding to the other permanent magnet, and the one permanent magnet and the corresponding yoke are moved. Does not couple with the magnetic path of the magnetic circuit formed by the other permanent magnet and its corresponding yoke,
The spring constants of the wire members 8a to 8b and the permanent magnets 3a,
Since there is only one stable point determined by the spring constant of the magnetic spring between 3b and the opposing yokes 4a, 4b, the linearity of the current sensitivity characteristic is ensured. As a result, it is possible to provide an objective lens driving device that can obtain stable servo characteristics and can be driven in the tilt direction. In addition, in an objective lens driving device capable of driving in the tilt direction, unnecessary resonance that is likely to occur when driven in the focusing direction F or the tracking direction T simultaneously with the tilt direction R can be suppressed with high reliability. Since the linearity of the current sensitivity characteristic is secured, more stable servo characteristics can be realized as a result.

In the first embodiment, the base 5
1 is a resin holding member 10 on which the metal support plate 9 is disposed.
And the opposing yokes 4a, 4b, the tracking coils 6a,
6b, and a metal fixed base 12 on which the focusing coils 7a and 7b are disposed, and the holding member 10 is formed by insert molding the metal support plate 9 and the fixed base 12
Since the metal support plate 9, the holding member 10, and the fixing base 12 are integrated by bonding or the like, unevenness in characteristics due to uneven application amount of the adhesive is eliminated. In addition, the number of steps can be reduced as compared with the case where they are integrated by the bonding or the like.

Embodiment 2 FIG. 5 is an exploded perspective view showing a configuration of an objective lens driving device according to Embodiment 2 of the present invention,
FIG. 6 is a top view schematically showing the configuration of the objective lens driving device of FIG. FIGS. 5 and 6 show a state in which the movable body is not driven, and FIG. 6 shows the bobbin in a cross section and the holding member in a see-through manner.

In these figures, the same reference numerals as those in FIGS. 1 and 2 indicate the same or corresponding parts, and the second embodiment will be described.
Uses an elastic support plate 17 made of a vibration damping material instead of the metal support plate 9 of FIGS.
1 and 2, the viscoelastic material 11 for the metal support plate of FIGS. 1 and 2 is not arranged, and the viscoelastic material storage holes 103 of the viscoelastic material storage portions 10a and 10b of the holding member 10 are stepped. The point that the ends on the side of the stepped recesses 10d and 10e are formed in a semi-closed state so as to communicate with the stepped recesses 10d and 10e through small wire member insertion holes 105 through which the wire members 8a to 8d are inserted. This is different from the first embodiment.

FIG. 7 is a sectional view showing a sectional structure of the elastic support plate 17 shown in FIGS. 5 and 6, wherein the elastic support plate 17 is made of a metal plate 111 made of an elastic metal material such as SUS or phosphor bronze. A plate-like viscoelastic member 112 made of a viscoelastic material such as silicon rubber is disposed between the metal plate 111 and a restraining plate 113 made of an elastic metal material such as SUS or phosphor bronze. The viscoelastic member 112 and the restraint plate 113 are made of a vibration damping material that is adhered to each other. Here, the damping material may be a material that does not include the restraint plate 113 and includes only the metal plate 111 and the viscoelastic member 112.

In the objective lens driving device configured as described above, when the elastic support plate 17 is deformed, the viscoelastic member 112 is deformed.
Tends to deform in the shearing direction, so that a resonance suppressing effect with a high damping rate can be obtained. Further, it is not necessary to fill the periphery of the movable portions 17a to 17d of the elastic support plate 17 with a viscoelastic material in order to suppress the resonance. When the elastic material is filled, the viscoelastic material does not leak to unnecessary parts and adhere to the optical component or the movable body, thereby preventing deterioration of optical or mechanical characteristics.
As a result, stable assembly is realized.

Embodiment 3 FIG. FIG. 8 is a top view schematically showing the configuration of the objective lens driving device according to the third embodiment of the present invention. The figure shows a state in which the movable body is not driven, the bobbin is shown in a cross section, and the holding member is shown in a transparent manner.

In the drawing, the same reference numerals as those in FIG. 2 denote the same or corresponding parts, and in the third embodiment, the opposed yoke 4a of the first bobbin 5a and the opposed yoke of the second bobbin 5b of the fixed member 12 are shown. 4b, a first permanent magnet 3a and a second magnet 3b are arranged on one side in the tangential direction K, and a third permanent magnet 3c and a fourth permanent magnet are also arranged on the other side. This embodiment differs from the first embodiment in that the magnet 3d is arranged.

That is, the first bobbin 5a and the second hobbin 5b are arranged such that each of the opposing yokes 4a and 4b has a lens holder 2 having a longer side in the tracking direction T.
The first permanent magnet 3a and the third permanent magnet are disposed at two long sides of the peripheral surface of the window 2a of the lens holder 2 in such a manner as to be located at the center of the window 2a in the tangential direction K. 3
c and a pair of the second permanent magnet 3b and the fourth permanent magnet 3d are arranged so as to be symmetrical with respect to the symmetry plane 102. And the first permanent magnet 3
a and the third permanent magnet 3c are connected to the respective pole faces 52a, 5a.
2c is disposed so as to face the opposing yoke 4a of the first bobbin 5a, and the second permanent magnet 3b and the fourth permanent magnet 3d
Means that each of the magnetic pole surfaces 52b, 52d is the second bobbin 5b
Is disposed so as to face the opposed yoke 4b. Further, two permanent magnets in the same pair, that is, a first permanent magnet 3a, a third permanent magnet 3c, and a second permanent magnet 3
b and the fourth permanent magnet 3d have two magnetization directions Ha and Hc, Hb and Hd opposite to each other, and are adjacent to each other in the tracking direction T, that is, the first permanent magnet 3a and the second permanent magnet 3d. Permanent magnet 3b and third permanent magnet 3
c and the fourth permanent magnet 3d have the same magnetization directions Ha and Hb, Hc and Hd.

Further, the support centers of the wire members 8a to 8d,
The driving centers of the first to fourth permanent magnets 3a to 3d with respect to the movable body 50 are set to substantially coincide with the center of gravity 101 of the movable body 50.

In the objective lens driving device configured as described above, the four permanent magnets 3a to 3d of the movable body 50 are
The magnetic pole surfaces 52a, 52c, 52b, 5 of each pair are provided on both sides in the tangential direction K with respect to the two opposing yokes 4a, 4b.
2d are arranged in pairs so as to oppose the yokes 4a and 4b in parallel and have the same polarity, so that the focusing coils 7a and 7b and the tracking coils 6a and 6b are provided with the respective focusing coils. 7a,
7b and the magnetic fluxes of the pairs of permanent magnets 3a and 3c, 3b and 3d interlink from both side surfaces of the tracking coils 6a and 6b.
In each of the tracking coils 6a and 6b, the effective coil length, which is the effective coil length for driving the movable body 50, is doubled. Therefore, a high driving force can be obtained, and the current sensitivity can be improved. As a result, low power consumption can be realized.

As shown in FIG. 9, the movable body 50
Even if it is driven in the tracking direction T to the maximum position in its movable range,
The two permanent magnets, that is, the first permanent magnet 3a and the second permanent magnet 3b, and the third permanent magnet 3c and the fourth permanent magnet 3d have their pole faces 52a and 52b, 52c and 52d having the same polarity. And the first permanent magnet 3a and the third permanent magnet 3c magnetize the corresponding opposing yoke 4a such that the end of the opposing yoke 4a in the B direction becomes an N pole. On the other hand, the second permanent magnet 3b and the fourth permanent magnet 3
Since the magnetic pole surfaces 52b and 52d of the permanent magnet 3d have N poles, the magnetic path of the magnetic circuit formed by the first and third permanent magnets 3a and 3c and the corresponding yoke 4a is Of the magnetic circuit formed by the permanent magnet 3b and the fourth permanent magnet 3d, and the corresponding yoke 4b. FIG. 9 shows a case where the movable body 50 is driven in the direction A, but the same applies to a case where the movable body 50 is driven in the direction B. Accordingly, in the servo in the tracking direction, a stable point determined by the spring constant of the wire members 8a to 8d and the spring constant of the magnetic spring between the permanent magnet 3a and the opposing yoke 4a and between the permanent magnet 3b and the opposing yoke 4b are obtained. Thus, the stability of the servo can be ensured. As a result, it is possible to provide an objective lens driving device that can achieve low power consumption and can obtain stable servo characteristics and can be driven in the tilt direction.

In the second embodiment, in the objective lens driving device of the first embodiment, the elastic support plate 1 made of a vibration damping material is used instead of the metal support plate and the viscoelastic material of the metal support plate.
7, the elastic support plate 17 made of a vibration damping material may be used in place of the metal support plate and the viscoelastic material of the metal support plate in the objective lens driving device of the third embodiment. .

[0061]

As described above, according to the first aspect of the present invention, the permanent magnet is provided on the movable body, the electromagnetic force generating means is provided on the base, and the base of the rod-shaped elastic support member for supporting the movable body is provided. In the objective lens driving device in which the end is movably supported in a tangential direction by the elastic support plate and the vibration of the elastic support plate is attenuated by the vibration damping member, the elastic support plate is made of metal, so that the surroundings are made. The characteristics are not degraded by a temperature change or a change over time, and a highly reliable resonance suppressing effect can be obtained. In addition, since it is a movable magnet type in which a permanent magnet is disposed on the movable body, there is no need to supply power through the rod-shaped elastic support member to drive the movable body.
It is not necessary to electrically insulate the rod-like elastic support members with an elastic support plate. Even if the elastic support plate is made of metal, the structure of the elastic support plate is optimal for suppressing the resonance of the rod-like elastic support member. Structure.

According to the second aspect of the present invention, two or more permanent magnets, a yoke, and a focusing coil are provided.
These are arranged so as to be substantially symmetrical with respect to a plane passing through the center of gravity of the movable body and parallel to the focusing direction and the tangential direction, and the movable body is also rotated in the rotational direction around the tangential direction in addition to the focusing direction and the tracking direction. In the objective lens driving device configured to be driven, two or more permanent magnets of the movable body are configured such that two magnets adjacent to each other in the tracking direction are both magnetized in the same direction. Even if one of the two adjacent permanent magnets moves to a position close to the yoke corresponding to the other permanent magnet, the permanent magnet is formed by the one permanent magnet and the corresponding yoke. The magnetic path of the magnetic circuit does not couple with the magnetic path of the magnetic circuit formed by the other permanent magnet and the corresponding yoke, and therefore the Constants, and for stable point determined by the spring constant of the magnetic spring between the permanent magnet and the yoke is one, the linearity of the current sensitivity is ensured. As a result, it is possible to provide an objective lens driving device that can obtain stable servo characteristics and can be driven in the tilt direction.

According to the third aspect of the present invention, the permanent magnet is provided on the movable body and the electromagnetic force generating means is provided on the base, and the movable body is driven by the electromagnetic force in the focusing direction and the tracking direction. In the objective lens driving device configured as described above, the permanent magnets of the movable body are arranged in pairs on both sides of the yoke of the electromagnetic force generating means in the thickness direction of the yoke so that the respective magnetic pole faces face the yoke in parallel. Therefore, the magnetic flux of a pair of permanent magnets interlinks from one side surface of the focusing coil and one tracking coil with respect to one focusing coil and one tracking coil, so that the movable body is driven in the focusing coil and the tracking coil. Since the effective coil length, which is the effective coil length, is doubled, a high driving force can be obtained and the current sensitivity It is possible to improve. As a result, low power consumption can be realized.

According to the invention of claim 4, according to claim 3,
In this invention, two or more pairs of permanent magnets, two or more yokes, and two or more focusing coils are provided, and these are arranged so as to be substantially symmetric with respect to a plane passing through the center of gravity of the movable body and parallel to the focusing direction and the tangential direction. The movable body is configured to be driven also in the rotational direction around the tangential direction, and two or more pairs of permanent magnets of the movable body are magnetized in the same direction by two magnets adjacent to each other in the tracking direction. Therefore, it is possible to provide an objective lens driving device capable of achieving low power consumption and achieving stable servo characteristics and capable of driving in the tilt direction.

Further, according to the invention of claim 5, according to claim 2,
In any one of the inventions of (4) to (4), the elastic member includes a rod-shaped elastic support member that supports the movable body, and an elastic support plate that supports a base end of the rod-shaped elastic support member so as to be elastically movable in a tangential direction, The elastic support plate has a vibration damping member that attenuates the vibration, and the elastic support plate is made of metal, so it is possible to obtain a highly reliable resonance suppression effect. An objective lens driving device capable of realizing low power consumption, which can have an optimal structure for suppressing resonance of the elastic support member, and an object capable of driving in the tilt direction, which can obtain stable servo characteristics. It is possible to provide a lens driving device or an objective lens driving device capable of realizing low power consumption and capable of driving in the tilt direction and capable of obtaining stable servo characteristics.

According to the invention of claim 6, according to claim 1,
Alternatively, in the invention according to the fifth aspect, the elastic support plate is formed of a vibration damping material obtained by attaching a plate-shaped viscoelastic member as a vibration damping member to a metal plate elastically deformable in a thickness direction. Therefore, when the elastic support plate is deformed, the viscoelastic member tends to deform in the shearing direction, so that a resonance suppressing effect with a high damping rate can be obtained. In addition, since it is not necessary to fill the viscoelastic material around the movable portion of the elastic support plate to suppress resonance, there is no variation in characteristics due to a variation in the filling amount of the viscoelastic material, and the viscoelastic material is filled. At this time, the viscoelastic material does not leak to unnecessary parts and adhere to the optical component or the movable body, thereby preventing deterioration of optical or mechanical characteristics. As a result, stable assembly is realized.

According to a seventh aspect of the present invention, in any one of the first, fifth and sixth aspects of the present invention, the base is formed of a resin holding member on which the elastic support plate is disposed, and the electromagnetic force generating member. Having a metal fixed base on which the means is disposed, wherein the fixed base is
Since the elastic support plate and the holding member are integrally formed by insert molding, the amount of adhesive applied when the elastic support plate, the holding member, and the fixing base are integrated by bonding or the like. Variations in characteristics due to unevenness can be eliminated, and man-hours can be reduced as compared with the case where the components are integrated by bonding or the like.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a configuration of an objective lens driving device according to a first embodiment of the present invention.

FIG. 2 is a top view schematically showing a configuration of the objective lens driving device of FIG.

FIG. 3 is a block diagram showing a configuration of a drive circuit in a focusing direction and a tilt direction of a movable body in the objective lens driving device of FIG. 1;

FIG. 4 is a top view schematically showing a driving operation of the movable body in a tracking direction of the objective lens driving device of FIG. 1;

FIG. 5 is an exploded perspective view illustrating a configuration of an objective lens driving device according to a second embodiment of the present invention.

FIG. 6 is a top view schematically showing a configuration of the objective lens driving device of FIG.

7 is a cross-sectional view showing a cross-sectional structure of an elastic support plate of the objective lens driving device in FIG.

FIG. 8 is a top view schematically showing a configuration of an objective lens driving device according to a third embodiment of the present invention.

9 is a top view schematically showing a driving operation of the movable body in a tracking direction of the objective lens driving device of FIG.

FIG. 10 is a top view schematically showing a structure of a conventional objective lens driving device that can be driven in a tilt direction.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Objective lens 2 Lens holder 2a Window 3a First permanent magnet 3b First permanent magnet 4a, 4b Opposed yoke 5a First bobbin 5b Second bobbin 6a, 6b Tracking coil 7a, 7b Focusing coil 8a to 8d Wire Member 9 Metal support plate 9a to 9d Movable part 10 Holding member 10a, 10b Viscoelastic storage part 10c Connecting part 10d, 10e Stepped recess 10f End face 11 Viscoelastic material for metal support plate 12 Fixed base 12a Main body part 12b Joint part 13 Tilt detector 14 Adder 15 Subtractor 16 Disk 17 Elastic support plate 17a-17d Movable part 50 Movable body 51 Base 52a-52d Magnetic pole surface 53 Slit 101 Center of gravity of movable body 102 Symmetry plane 103 Viscoelastic material storage hole 104 Wire member Viscoelastic material for wire 105 Wire insertion hole 109 Fixed support 111 metal plate 112 viscoelastic member 113 constraining plate A, the direction F focusing direction Ha~Hd magnetization direction J optical axis K tangential R tilt direction T tracking direction B the tracking direction T

Claims (7)

[Claims] 1. An objective lens which is incorporated in an apparatus for optically recording or reproducing information on a disk-shaped recording medium and has an optical axis when not driven in a focusing direction which is a direction perpendicular to the disk-shaped recording medium. A movable body having a lens holder for holding the objective lens, and a permanent magnet provided in the lens holder; a base; and a tangential direction to the base in a predetermined direction perpendicular to the focusing direction. An elastic support plate disposed so as to be elastically deformable, and the movable body is elastically movable with respect to the elastic support plate in the focusing direction and a tracking direction perpendicular to the focusing direction and the tangential direction. A plurality of rod-shaped elastic support members having a distal end fixed to the movable body and a proximal end fixed to the elastic support plate so as to support; a vibration damping member for attenuating vibration of the elastic support plate An objective lens driving means provided with electromagnetic force generating means disposed on the base and driving the movable body with electromagnetic force in the focusing direction and the tracking direction by interaction with the permanent magnet of the movable body; In the device, the elastic support plate is made of metal. 2. An objective lens which is incorporated in an apparatus for optically recording or reproducing information on a disc-shaped recording medium, and has an optical axis when not driven in a focusing direction which is a direction perpendicular to the disc-shaped recording medium. A movable body having a lens holder for holding the objective lens, and two or more permanent magnets disposed on the lens holder; a base; and the movable body with respect to the base, the focusing direction, and An elastic member for supporting elastically movable in a tracking direction, which is a predetermined direction perpendicular to the focusing direction; and a plate-shaped magnetic body disposed on the base so as to extend in the focusing direction and the tracking direction. The above-mentioned yokes, two or more focusing coils respectively wound around the two or more yokes so as to have a winding axis in the focusing direction, And electromagnetic force generating means having two or more tracking coils wound around the two or more yokes so as to have a winding axis in the tracking direction, two or more permanent magnets of the movable body, and The two or more yokes and the two or more focusing coils of the electromagnetic force generating means are passed through the center of gravity of the movable body when not driven, and in the focusing direction, and a tangential direction perpendicular to the focusing direction and the tracking direction. The movable body is arranged by the electromagnetic force generating means to interact with the permanent magnet of the movable body, so that the focusing direction, the tracking direction, and In an objective lens driving device configured to be driven by an electromagnetic force in a tilt direction which is a rotation direction around the tangential direction, An objective lens driving device, wherein two or more permanent magnets of the movable body are magnetized in the same direction in two adjacent magnets in the tracking direction. 3. An objective lens which is incorporated in an apparatus for optically recording or reproducing information on a disk-shaped recording medium and has an optical axis when not driven in a focusing direction which is a direction perpendicular to the disk-shaped recording medium. A movable body having a lens holder for holding the objective lens, and a permanent magnet provided in the lens holder; a base; and the focusing direction, and the focusing direction; An elastic member for supporting an elastic movement in a tracking direction that is a predetermined direction perpendicular to the base; a yoke made of a plate-shaped magnetic material disposed on the base so as to extend in the focusing direction and the tracking direction; A focusing coil wound around the yoke so as to have a winding axis in the focusing direction, and the tracking direction around the yoke. An electromagnetic force generating means having a tracking coil wound to have a winding axis and driving the movable body by electromagnetic force in the focusing direction and the tracking direction by interaction with a permanent magnet of the movable body The permanent magnet of the movable body is paired on both sides of the yoke in the thickness direction of the yoke of the electromagnetic force generating means such that respective magnetic pole surfaces face in parallel with the yoke. An objective lens driving device, wherein: 4. The objective lens driving device according to claim 3, wherein the movable body has two or more pairs of permanent magnets, and the electromagnetic force generating means includes the yoke, the focusing coil, and the tracking coil. Having at least two pairs of permanent magnets of the movable body, and two or more yokes and two or more focusing coils of the electromagnetic force generating means, passing through the center of gravity of the movable body and in the focusing direction and the tracking direction. The movable body is arranged so as to be substantially symmetrical with respect to a plane parallel to a tangential direction which is a vertical direction, and the electromagnetic force generating means drives the movable body by electromagnetic force also in a rotational direction around the tangential direction. The two or more pairs of permanent magnets of the movable body are configured so that two magnets adjacent in the tracking direction are both magnetized in the same direction. Lens driving device. 5. The objective lens driving device according to claim 2, wherein the elastic member is provided on the base so as to be elastically deformable in the tangential direction. A plurality of rod-like elastic support members having a distal end fixed to the movable body and a proximal end fixed to the elastic support plate so as to support the movable body with respect to the elastic support plate so as to be elastically movable in the focusing direction and the tracking direction. An objective lens driving device, comprising: a vibration damping member configured to dampen the elastic support plate, wherein the elastic support plate is made of metal. 6. The objective lens driving device according to claim 1, wherein the elastic support plate is formed by attaching a plate-shaped viscoelastic member as the vibration damping member to a metal plate elastically deformable in a thickness direction. An objective lens driving device comprising a vibration damping material to be worn. 7. The objective lens driving device according to claim 1, wherein the base includes a resin holding member provided with the elastic support plate, and the electromagnetic force generating unit. Is provided, and has a metal fixed base, the fixed base is, by insert molding,
An objective lens driving device, which is formed integrally with the elastic support plate and the holding member.