JP2749952B2 - Objective lens drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an objective lens driving device, and more particularly, to controlling a track shift and a focus shift of a light spot focused on an information recording surface of an optical information recording medium. The present invention relates to an objective lens driving device for a reproducing device or a recording device.

[Prior Art] FIGS. 32 to 35 are views showing a conventional objective lens driving device. FIG. 32 is an exploded perspective view, FIG. 33 is a plan view, and FIG. 34 is IX-IX in FIG. 35 is a partially enlarged view of FIG. 34. In the figure, (1) is an objective lens for forming a laser beam spot on an optical information recording medium (not shown), and (3) is a movable holder, which is supported via a central bearing (4). The objective lens (1) is held rotatably and vertically movable by (5), and is held at a position eccentric from the support shaft (5). (2) is a counterweight for balancing the objective lens (1) on the movable holder (3) around the support shaft (5), and (6) elastically moves the movable holder (3). (7) a supporting rubber for holding the movable holder (3) on a support shaft (5)
(8a) and (8b) are the movable holders (3) for sliding control in the direction of arrow A in FIG.
A track control permanent magnet for rotating the shaft in the direction of arrow B in FIG. 32 around the support shaft (5), and (9) holds the support shaft (5) and the focus control permanent magnet (7). A focus control yoke, (10) is a focus control coil, which is attached to the movable holder (3) and is attached to the movable holder (3) by a magnetic flux by a focus control permanent magnet (7). Along with the driving force in the focus control direction, resulting in the focus control direction of the objective lens (1) (arrow A in the figure).
Direction) movement. Reference numerals (11a) and (11b) denote track control coils, which apply a rotating force about the support shaft (5) to the movable holder (3) by the magnetic flux generated by the track control permanent magnets (8a) and (8b). As a result, the objective lens (1) is given a movement in the track control direction.
(12a) and (12b) are the track control permanent magnets (8
This is a track control yoke for adhesively fixing a) and (8b). (13a), (13b), (13c), and (13d) are support rubber mounting portions, and the track control yokes (12a), (12
The supporting rubber (6) holding the movable holder (3) is fixed integrally with the fixed base (14) together with b).
(15) is a hole for guiding a laser beam to the objective lens (1) through the fixing table (14).

 Next, the operation will be described.

Although not shown, when the light spot formed by the objective lens (1) is out of focus with respect to the optical information recording medium, control according to the focus sensor output detected by the out-of-focus detection means is performed. The current is supplied to the focus control coil (10) shown in the figure, and the movable holder (3) moves up and down in the direction of arrow A in FIG. 32 to control the focus of the objective lens (1).

Although not shown, when the light spot formed by the objective lens (1) has a track shift with respect to the track of the optical information recording medium, the track sensor output detected by the track shift detecting means is detected. The control current corresponding to the track control coil (11
a) and (11b), the movable holder (3) rotates in the direction of arrow B in FIG. 32, and the track of the objective lens (1) is controlled.

39 to 47 are views showing another conventional objective lens driving device according to the present invention. FIG. 39 is a plan view thereof, and FIG.
FIG. 41 is a side view thereof, FIG. 41 is a cross-sectional view taken along line XX of FIG. 39, FIG. 42 is a plan view showing a state where a protective cover is removed,
The figure is a side view with the protective cover removed, FIG. 44 is the state with the movable part and the support spring of the objective lens driving device removed,
That is, a plan view of the fixing part, FIG. 45 is a partial cross-sectional view showing a mounting state of the support spring along the XI-XI in FIG. 42 on the fixing part side, FIG. 46 is a bottom view of the protective cover, and FIG. Is the XI in Figure 46
It is sectional drawing which follows I-XII. 39 to 47, reference numeral (300) denotes an objective lens, (301) denotes a movable holder, and a bearing (302) is provided at a central portion.
The objective lens (300) is fixedly held at a position decentered by a predetermined distance. (303) is the movable holder (30
1) Focus control coil provided at the bottom of (304a),
(304b) a radially magnetized focus control permanent magnet for controlling the focus of the objective lens (300), (305)
Is a focus control yoke for slidingly driving the movable holder (301), and (306a) and (306b) are the movable holder (30).
1) A track control coil for rotating and driving (307)
(a) and (307b) are two-pole magnetized permanent magnets for track control, (308a) and (308b) are back yokes formed on the back of the permanent magnets for track control, (309) is a base, (309) Three
10) is a support shaft erected on the base (309) via the focus control yoke (305), (311) is a protective cover covering the base, (312a), (312b), (312c), (312d) are cover mounting holes for positioning and fixing the protective cover (311) provided on the base (309), (313a), (313b), and (31).
3c) and (313d) are cover mounting bosses for positioning and fixing the protective cover (311) to the base (309), and (314) is an object lens (300) provided on the protective cover (311). An objective lens hole (315) for passing a light beam (not shown) is provided, and a light beam hole (315) for passing a light beam (not shown) incident on the objective lens (300) provided on the base (309). , (316) is a counter weight, (317) is a support spring that elastically holds the movable holder (301) and supports the neutral position of the objective lens (300),
(318a) and (318b) are support spring attachment portions for fixedly attaching the support spring (317) to the movable holder (301);
(319a), (319b), (319c) and (319d) are support spring receiving surfaces provided on the base (309), (320a) and (320).
b), (320c) and (320d) are support spring receiving surfaces (319a) and (3) for fixing the support spring (317) to the base (309).
19b), (319c), (319d) provided support spring holding bosses (321a), (321b), (321c), (321d) fix the support spring (317) to the base (309). Spring fixing part for the

Support spring fixing parts (321a), (321b), (321c), (32
1d) includes spring fixing holes (321a) for fitting into the support spring holding bosses (320a), (320b), (320c), and (320d) as shown in FIGS. 321b), (321
c), (321d) and the adhesive (324a), (324b), (324) so that the support spring (317) does not come off the support spring holding boss.
c), adhesive receiving holes (323a) for (324d), (323
b), (323c) and (323d). That is, the support spring (317) is attached to the base (309) by the support spring holding boss (320).
a), (320b), (320c), (320d) through the adhesive (3
24a), (324b), (324c), and (324d).

The bearing (302) has a movable holder (301) fitted to the support shaft (310) so as to be rotatable in the direction of arrow A in FIG. 39 and to be able to move up and down in the direction of arrow B in FIG.

Further, the protective cover (311) is attached to the base (309) by the cover mounting holes (312a), (312b), (312c), (312d) and the cover mounting bosses (313a), (313b), (313c), (313d). ).

 Next, the operation will be described.

When a control current corresponding to the amount of defocus is applied to the focus control coil (303), the movable holder (301) moves up and down in the direction of arrow B in FIG. 40, and the focus of the objective lens (300) can be controlled. . Also, track control coils (306a), (30
When a control current corresponding to the track shift amount is supplied to 6b), the movable holder (301) rotates in the direction of arrow A in FIG. 39, and the track of the objective lens (300) can be controlled.

Since the conventional objective lens driving device is configured as described above, in the devices shown in FIGS. 32 to 35, the movable holder (3) can be freely rotated and vertically moved with respect to the support shaft (5). 35, a gap G exists between the bearing (4) and the support shaft (5), and generally G = 2.
It is designed to be about 5 μm. Further, a counterweight (2) is provided on the movable holder (3) in order to maintain a static balance in the rotating direction of the movable portion mainly composed of the movable holder (3) including the objective lens (1). It is difficult to match the position of the center of gravity of the movable lens in the sliding direction of the objective lens (1) with the position of the center of gravity of the counterweight (2). Although it is on the axis in the sliding direction, the main axis of inertia of the movable part does not coincide with the axis in the sliding direction.

That is, since the pivot axis of the movable holder (3) does not coincide with the principal axis of inertia of the movable portion, when the movable holder (3) rotates along with the track direction control operation, the movable holder (3) falls within the gap G. Vibration such as occurs, the bearing (4) and the support shaft (5) collide, and the vibration due to the collision is transmitted to the objective lens (1) via the movable holder (3), as shown in an example in FIG. Track control direction frequency characteristics 1KHz-3K
There was a problem that the characteristic was disturbed in the frequency range of Hz.

In particular, since the frequency range of 1 KHz to 3 KHz generally matches the cutoff frequency of the servo system in the track control direction, if there is any characteristic disturbance in this part, the servo system becomes unstable and stable track control is obtained. Can no longer be done.

Further, the influence of the structural resonance of the movable holder (3) appears on the objective lens (1), and this is detected by the output of the focus sensor and the output of the track sensor, and there is a problem that the controllability of the objective lens driving device is deteriorated.

This structural resonance has a characteristic that even if the resonance frequency can be increased by the shape and the material, it cannot be basically avoided in a structure. Moreover, in recent years, information recording / reproducing apparatuses have been required to be small, light and thin, and high-speed information transfer has been demanded. Therefore, it is desired to widen the servo band of the objective lens driving apparatus. Under such circumstances, the movable holder (1)
It is extremely difficult to increase the structural resonance frequency of the movable part including tens of KHz or more.

[Problem to be Solved by the Invention] In the structure of the objective lens driving device as shown in FIG.
Structural resonance appearing at the lowest frequency often results in a bending primary mode of the movable holder (3) as shown by a solid line in the explanatory diagram of FIG. 37, and appears as a displacement in the focus control direction on the objective lens (1). . The frequency characteristics of such an objective lens driving device in the focus control direction are as shown in FIG. 38. The resonance frequency f is about 20 KHz, and the resonance peak amount Q is about 20 to 25 dB. In the case where the servo band is wide, if the resonance frequency f is low or the resonance peak amount Q is large, there is a problem that the servo characteristics become extremely unstable and sometimes cause oscillation.

In the apparatus shown in FIGS. 39 to 47, an adhesive (324a) is used to fix the support spring (319) to the base (309).
(324b), (324c), (324d)
When applying the adhesives (324a), (324b), (324c), and (324d) to other components, especially to the components that make up the movable portion, the characteristics of the objective lens driving device are adversely affected. Adhesives (324a), (324b), (324c), (324
The coating operation of d) has a problem that it becomes very complicated.

The spring material of the support spring (317) generally used in the objective lens driving device using the support shaft (310) and the bearing (302) is as follows:
Since rubber-based materials are used, adhesives (324a), (324
b), (324c), and (324d) also become rubber-based adhesives, which means that a highly viscous adhesive must be applied, and the adhesive draws a thread during application, and the application operation takes a very long time. there were.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an objective lens driving device capable of reducing the amount of deformation of a movable portion due to a bending primary mode of the movable portion and securing stable servo characteristics and a wide servo band.

[Means for Solving the Problems] An objective lens driving device according to the present invention is provided with a movable holder rotatably and slidably held on a support shaft, and a movable holder eccentric to the support shaft. And a driving mechanism for driving the movable holder in a rotating and sliding direction, the bearing being provided on the movable holder and allowing the support shaft to pass through, and rotating and sliding the movable holder. In the objective lens driving device which performs track control and focus control of a light spot condensed on the optical information recording medium via the objective lens by performing the above operation, the objective lens is deformed by giving a potential difference, and is deformed by giving the deformation. A solid actuator, which is an element that causes the above, is integrated with the movable holder.

[Operation] In the present invention, a solid actuator is provided in a movable holder, and besides focus control and track control by a focus control coil and a track control coil, bends in a frequency band near a resonance frequency of a bending primary mode of a movable portion. A current corresponding to the deformation amount of the primary mode is supplied to the solid actuator, and the bending primary mode of the movable portion is actively suppressed.

Thereby, the structural resonance of the bending first mode in the movable portion can be suppressed, so that the resonance peak amount Q appearing in the frequency characteristic in the focus control direction can be reduced, and a stable servo characteristic and a wide servo band can be obtained. it can.

Embodiment An embodiment of the objective lens driving device according to the present invention will be described with reference to the drawings.

REFERENCE EXAMPLE FIGS. 1 to 5 show a reference example, in which the same or corresponding parts as those in the conventional objective lens driving device shown in FIGS. 32 to 35 are denoted by the same reference numerals. Omitted.

1 is an exploded perspective view, FIG. 2 is a plan view, and FIG.
FIG. 4 is a partially enlarged view of FIG. 3, and FIG. 5 is a track control direction frequency characteristic diagram of the objective lens driving device.

In this reference example, the bearing (4) is attached to the movable holder (3) via a butyl rubber sleeve (100).

 Next, the operation will be described.

Although not shown, when the light spot formed by the objective lens (1) is out of focus with respect to the optical information recording medium, a control current corresponding to the output of the focus sensor detected by the out-of-focus detection means is used. Is supplied to the focus control coil (10) shown in the figure, and the movable holder (3)
Slides in the direction of arrow A in FIG. 1 to control the focus of the objective lens (1).

Further, when the light spot formed by the objective lens (1) causes a track shift with respect to the track of the optical information recording medium, a control current corresponding to the track sensor output detected by the track shift detecting means is used for track control. The movable holder (3) is supplied to the coils (11a) and (11b) for use, and the movable holder (3) rotates in the direction of arrow B in FIG.
Track control is performed.

At this time, the rotational axis of the movable holder (3) does not coincide with the inertia principal axis of the movable portion mainly including the movable holder (3) including the objective lens (1). Even if the support shaft (5) collides, the vibration caused by the collision is absorbed by the butyl rubber sleeve (100), the vibration is attenuated and transmitted to the objective lens (1), and the influence of the vibration is exerted on the objective lens (1). Has become difficult to appear.

As a result, as shown in FIG. 5, there is no disturbance in the characteristic which appears in the conventional 1 KHz to 3 KHz shown in FIG. 36, and a good frequency characteristic can be obtained.

In the reference example shown in FIGS. 1 to 4, a sleeve-shaped vibration isolator made of one butyl rubber sleeve (100) is used, but as in the reference example shown in FIG. Two bushes made of butyl rubber material (101
a), the bearing (4) is connected to the movable holder (3) via (101b).
The same effect as in the above-described reference example can be obtained even if it is attached to the first embodiment.

7, the bearing (4) may be attached to the movable holder (3) with a rubber-based adhesive, for example, a silicone rubber adhesive (102). ) Functions as an anti-vibration member, and the same effects as in the above reference example can be obtained.

Embodiment FIGS. 8 to 12 show an embodiment of an objective lens driving apparatus according to the present invention. In the drawings, the same or corresponding parts as those in the conventional example shown in FIGS. 32 to 37 are denoted by the same reference numerals. , The description of which is omitted.

FIG. 8 is an exploded perspective view, FIG. 9 is a partial plan view of FIG. 8,
FIG. 10 is a sectional view taken along the line II-II of FIG. 9, FIG. 11 is a simplified block diagram showing a control circuit of a focus control direction of the objective lens driving device according to the present invention, and FIG. It is a figure showing an open loop characteristic (frequency characteristic) of a control direction. The feature of this embodiment lies in the structure of the movable holder (200), and the other parts are the same as those of the conventional example shown in FIGS. 32 to 37. (201) is a piezoelectric actuator integrally provided inside the movable holder.
1a) and an electrode plate (201b).

In FIG. 11, (31) is a focus sensor output, (32) is a phase compensation circuit, (33) is an amplifier, (34) is a bandpass filter, and (35) is an amplifier.

 Next, the operation will be described.

The focus sensor output (31) detected by a defocus detecting means (not shown) is phase-compensated by a phase compensation circuit (32), amplified by an amplifier (33), applied to a focus control coil (10), and moved. The holder (200) moves up and down in the direction of arrow A in FIG. 8 to control the focus of the objective lens (1). On the other hand, the signal output from the phase compensation circuit (32) is a band-pass filter (3
4), a component near the structural resonance (first bending mode) frequency of the movable portion including the movable holder (200) is extracted, amplified by an amplifier (35), and applied to the piezoelectric actuator (201). (First bending mode)
The deformation of the movable holder (200) due to is suppressed. That is, as described in detail later, the piezoelectric actuator (201)
The movable holder (200) can be bent in the direction opposite to the deformation due to the resonance. In other words, a reactive force against the vibration force can be applied to the movable holder.

Also, a control current corresponding to the output of the track sensor detected by the track deviation detecting means (not shown) is supplied to the control coils (11a) and (11b), and the movable holder (200) is moved in the direction of arrow B in FIG. And the track of the objective lens (1) is controlled.

As described above, according to the present invention, unnecessary resonance (primary bending mode) generated by the movable holder (200) and the like can be suppressed, so that displacement due to the primary bending mode hardly appears on the objective lens (1). Therefore, the frequency characteristic in the focus control direction is as shown in FIG. 12, and the resonance peak amount Q of gain due to structural resonance (bending first mode) generated by the movable holder (201) can be reduced to about 4 dB. An objective lens driving device that has good servo characteristics and a wide servo band can be obtained.

Note that the same effects can be obtained with the configurations shown in FIGS. 13 and 14, 15 and 16, and therefore, another embodiment of the present invention will be described below.

13 and 14 show another embodiment. FIG. 13 is a cross-sectional view along a portion corresponding to II-II in FIG. 9, and FIG. 14 is a conceptual diagram showing a driving method of a piezoelectric actuator provided inside the movable holder (200).

In the drawing, reference numerals (202) and (203) denote a pair of piezoelectric actuators provided integrally inside the movable holder (200) so as to face each other. The piezoelectric actuator (202) includes a piezoelectric element (202a) and an electrode plate (202b). The polarization directions of the piezoelectric elements (202a) and (203a) are different as indicated by arrows X and Y in FIG. With this configuration, when a displacement due to structural resonance (first bending mode) of the movable holder (200) or the like is applied to the piezoelectric actuator (202), a voltage corresponding to the displacement is applied. When this is applied to the voltage actuator (203) via the phase compensation circuit (36) and the amplifier (37), a bending mode in a direction opposite to the bending direction applied to the piezoelectric actuator (202) occurs in the piezoelectric actuator (203). The structural resonance (first-order bending mode) can be suppressed.

In addition, bending mode detection piezoelectric actuator (202)
Although a unimorph can be used as the bending mode suppressing piezoelectric actuator (203), the same effect can be obtained by using one bimorph (204) as shown in FIGS.

 Hereinafter, still another embodiment will be described.

FIG. 15 is a sectional view taken along a portion corresponding to II-II in FIG. 9, and FIG. 16 is a conceptual diagram showing a driving method of a piezoelectric actuator provided in the movable holder (200).

In the drawing, reference numeral (204) denotes a piezoelectric actuator integrally provided inside the movable holder (200).
Piezoelectrons (204a) with different polarization directions as shown as Y,
(204b) and an electrode plate (204c). With such a configuration, the movable holder (20
0) and other structural resonances (first-order bending mode)
When acting on the piezoelectric element (204a), a voltage corresponding to the amount of bending displacement is output. When this is applied to the piezo-electrons (204b) via the phase compensation circuit (38) and the amplifier (39), a bending mode in the opposite direction to the bending acting on the piezo-electrons (204a) occurs in the piezo-electrons (204b). The structural resonance (first-order bending mode) can be suppressed. In this embodiment, an example using a piezoelectric element as a solid actuator has been described. However, any element may be used as long as it is deformed by giving a potential difference and generates a potential difference by giving a deformation.

Further, in this embodiment, the description has been made with reference to the example of the shaft sliding / rotating type objective lens driving device. However, for example, application to an objective lens driving device having another configuration such as a leaf spring supporting type is also possible.

REFERENCE EXAMPLE FIGS. 17 to 22 show a reference example, in which the same or corresponding parts as in the conventional example shown in FIGS. 39 to 47 are denoted by the same reference numerals, and description thereof will be omitted. FIG. 17 is a plan view, FIG. 18 is a plan view with the protective cover (311) removed, FIG.
9 is a side view of FIG. 18, FIG. 20 is a bottom view of the protective cover (311), FIG. 21 is a cross-sectional view along IV-IV of FIG. 20, and FIG. 22 is III-III of FIG. FIG.

In the figure, support springs (317) are provided on support bases (309) on support spring receiving surfaces (319a), (319b), (319c), and (319d). Support spring holding bosses (320a) and (320b) , (320c),
(320d) support spring fixing parts (321a), (321b),
(321c) and (321d) are positioned.

As shown in FIG. 19, the support spring holding bosses (320a), (320b), (320c), and (320d) are provided with support spring fixing portions (321a), (321b), (321c), and (321c). 321d) so as to protrude by a desired amount. The support spring holding bosses (320a), (320b), (320c), and (320d) have support spring fixing holes (330) provided in the holding cover (311).
a), (330b), (330c) and (330d) are fitted, and the upper surfaces of the support spring fixing portions (321a), (321b), (321c) and (321d) are the support spring holding surfaces (331a) and (331a). 331b), (331
c) and (331d), the support spring fixing part (3
21a), (321b), (321c), and (321d) are fixed to the base (309).

As described above, the support spring (317) is provided with the support spring holding bosses (320a), (320b), (320) provided on the base (309).
c), (320d) and support spring fixing holes (330a), (330b), (330c), (330) provided in the protective cover (311).
It is fixed to the base (309) by d). Further, the fixing of the protective cover (311) to the base (309) is similarly performed. The operation is the same as that of the conventional example, and the description is omitted.

In the reference example, the support spring holding boss (3
20a), (320b), (320c), and (320d) are attached to the protective cover (311) by the support spring fixing holes (330a), (330b), and (3
30c) and (330d), but as shown in FIG. 23, the support spring fixing holes (332
a), (332b), (332c) and (332d) are provided and the support spring holding bosses (333a), (333b) and (333) are provided on the protective cover (311).
c) and (333d) may be provided.

In each of the reference examples, the positioning of the support spring fixing portions (321a), (321b), (321c), and (321d) of the support spring (317) in the rotation direction was not uniquely determined.
With a configuration like the reference example shown in FIG. 27, the positioning of the support spring fixing portions (321a), (321b), (321c), and (321d) in the rotational direction can be univocally performed.

FIG. 24 is a bottom view of the protective cover (311), and FIG.
FIG. 26 is a sectional view taken along the line VV in the figure, and FIG. 26 is a protective cover (311).
FIG. 27 is a cross-sectional view taken along the line VI-VI in FIG. 26 with the protective cover (311) attached, with the cover removed.

In the figure, the support spring (317) is attached to the base (3
09) Support spring holding bosses (320a), (320b), (320
c), (320d) support spring fixing part (321a), (321
b), (321c), and (321d) are positioned. Furthermore, square bosses (334a) and (3
34b), (334c), (334d) and support spring fixing part (321
a) Square holes (335a), (335b), (335c), (335d) provided on the upper surfaces of (321b), (321c), and (321d)
The support spring fixing portions (321a), (32
1b), (321c), and (321d) are positioned in the rotational direction. Support spring fixing part (321a), (321b), (321c),
The (321d) is fixed to the base (309) in the same manner as in the seventh embodiment.

In each of the above reference examples, the support spring fixing portions (321a), (321b), (321) are fitted by fitting a boss provided on the base (309) or a hole or boss provided on the hole protection cover (311). 321c), (321d) base (30
9) and the protective cover (311) were fixed to the base (309). However, by adopting a hook structure as shown in FIGS. The fixing portions (321a), (321b), (321c), and (321d) can be fixed to the base (309) and the protective cover (311) can be fixed to the base (309).

FIG. 28 is a bottom view of the protective cover (311), and FIG.
FIG. 30 is a sectional view taken along the line VII-VII of FIG.
FIG. 31 is a plan view with 1) removed, and FIG. 31 is a cross-sectional view along a portion corresponding to VIII-VIII in FIG. 30 with the protective cover (311) attached.

The protective cover (311) has a hook (336a), (336
b), (336c) and (336d) are provided, and the support rubber fixing portions (321a), (321b), (321c) and (321d) have support spring fixing concave portions (337a) and (337b) ), (337
c) and (337d) are provided, and the notches (338a), () for hook receiving are provided below the support spring receiving surfaces (319a), (319b), (319c), and (319d) of the base (309). 338b), (338
c) and (338d) are provided.

Support spring fixing parts (321a), (321b), (321c), (32
1d) are hooks (336a), (336b), (336c), (33
6d) positioned by the side of the hook (336a),
(336b), (336c), (336d) and the hook receiving notches (338a), (338b), (338c), (338d) are engaged to support rubber fixing portions (321a), (321b), (321
c), (321d), support spring receiving surface (319a), (319b),
(319c), (319d) support spring holding surface (331a), (331
b), (331c), (331d)
09) is fixed.

In this reference example, the support rubber fixing portions (321a), (321
b), (321c), (321d) The support spring fixing recess (3
37a), (337b), (337c), and (337d) are provided. Instead, the support spring fixing parts (321a), (321b), and (32
Similar effects can be obtained by providing square holes in 1c) and (321d).

[Effects of the Invention] According to the present invention, it is possible to actively suppress a structural resonance such as a bending mode generated in a movable portion of an objective lens driving device, so that a stable servo characteristic can be obtained without increasing the rigidity of the movable portion. In addition, an objective lens driving device having a wide servo band can be obtained.

Further, since the structural resonance is actively suppressed, a desired servo band can be secured even if the movable portion is thinned.

[Brief description of the drawings]

1 to 5 are views showing a reference example, FIG. 1 is an exploded perspective view, FIG. 2 is a plan view, FIG. 3 is a sectional view taken along the line II of FIG. 2, and FIG. FIG. 3 is a partially enlarged view of FIG. 3, FIG. 5 is a view showing an example of a frequency characteristic in a track control direction, FIGS. 6 and 7 are cross-sectional views showing another reference example, and FIGS. FIG. 8 is an exploded perspective view, FIG. 9 is a partial plan view of FIG. 8, and FIG. 10 is a cross-sectional view taken along the line II-II of FIG. FIG. 11, FIG. 11 is a simplified block diagram showing a control circuit in the focus control direction, FIG. 12 is a diagram showing an example of frequency characteristics in the focus control direction of the objective lens driving device according to the present invention, FIG. 13 and FIG. 13 is a sectional view showing another embodiment of the present invention, FIG. 14 is a conceptual view showing a driving method of a piezoelectric actuator, FIG. 15 and FIG.
FIG. 15 is a view showing still another embodiment of the present invention, FIG. 15 is a sectional view, FIG. 16 is a conceptual view showing a driving method of a piezoelectric actuator, and FIGS. 17 to 22 are views showing a reference example. 17 is a plan view, FIG. 18 is a plan view with the protective cover removed, FIG. 19 is a side view of FIG. 18, FIG. 20 is a bottom view of the protective cover, and FIG. FIG. 22 is a sectional view taken along the line IV-IV, FIG. 22 is a sectional view taken along the III-III in FIG. 17, FIG. 23 is a sectional view corresponding to FIG. 22 showing another reference example, and FIGS. FIG. 27 is a view showing another reference example, FIG. 24 is a bottom view of the protective cover, and FIG.
FIG. 24 is a sectional view taken along the line VV in FIG. 24, FIG. 26 is a plan view with the protective cover removed, and FIG. 27 is a view along the line VI-VI in FIG. 26 with the protective cover attached. FIG. 28 to FIG. 31 are views showing another reference example, and FIG.
FIG. 29 is a bottom view of the protective cover, FIG. 29 is a sectional view taken along the line VII-VII of FIG. 28, FIG. 30 is a plan view of the state with the protective cover removed, and FIG. 31 is a state of the state with the protective cover attached. FIG. 30 is a cross-sectional view taken along a portion corresponding to VIII-VIII, FIGS. 32 to 36 are views showing a conventional objective lens driving device, FIG. 32 is an exploded perspective view, FIG. 33 plan view, and FIG. Is a sectional view taken along line IX-IX of FIG. 33, FIG. 35 is a partially enlarged view of FIG. 34, FIG. 36 is a frequency characteristic diagram in the track control direction, and FIG. 37 is a structural resonance in the configuration of FIG. 38 is a diagram showing an example of frequency characteristics in the focus control direction in FIG. 32, FIGS. 39 to 47 are diagrams showing a conventional objective lens driving device, and FIG. 39 is a plan view , 40th
FIG. 41 is a side view, FIG. 41 is a cross-sectional view taken along XX of FIG.
42 is a plan view with the protective cover removed, FIG. 43 is a side view of FIG. 42, FIG. 44 is a plan view of the fixing portion, and FIG. 45 is a partial cross-sectional view along XI-XI of FIG. 46 is a bottom view of the protective cover, and FIG. 47 is a sectional view taken along the line XII-XII of FIG. In the figure, (1) is an objective lens, (2) is a counterweight, (3) is a movable holder, (4) is a bearing, (5)
Is a spindle, (10) is a focus control coil, (11a) and (11b) are track control coils, (100) is a butyl rubber sleeve, (101a) and (101b) are butyl rubber bushes, and (10
2) is silicone rubber adhesive, (200) is movable holder, (20)
1), (202), (203), and (204) are piezoelectric actuators, (201a), (202a), (203a), (204a), (204)
b) is piezoelectric, (201b), (202b), (203b), (204)
c) is an electrode plate, (300) is an objective lens, (301) is a movable holder, (303) is a bearing, (309) is a base, (310) is a support shaft, (311) is a protective cover, and (317) ) Is the support spring, (319
a) to (319d) are support spring receiving surfaces, and (320a) to (320)
d), (333a) to (333d) are support spring holding bosses, (321)
a) to (321d) are support spring fixing portions, and (330a) to (330)
d), (332a) to (332d) are support spring fixing holes, (331)
a) to (331d) are support spring holding surfaces, (334a) to (334d)
Are square bosses, (335a) to (335d) are square holes, (336
a) to (336d) are hook portions, (337a) to (337) are support spring fixing concave portions, and (338a) to (338d) are hook receiving notches. In the drawings, the same reference numerals indicate the same or corresponding parts.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 7/09 D

Claims (1)

(57) [Claims] A movable holder rotatably and slidably held on a support shaft, an objective lens provided at an eccentric position of the movable holder with respect to the support shaft, and a support provided on the movable holder. An optical information recording medium including a bearing that allows a shaft to pass through, and a drive mechanism that drives the movable holder in a rotating and sliding direction, and rotating and sliding the movable holder through the objective lens In the objective lens driving device for performing track control and focus control of a light spot focused on a movable holder, a solid actuator, which is an element that is deformed by giving a potential difference and generates a potential difference by giving a deformation, is integrated with the movable holder. An objective lens driving device, which is incorporated in a camera.