JP2001266379A - Biaxial actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form at a low cost a biaxial actuator capable of ensuring excellent positional precision to a pickup base. SOLUTION: A first member 9 having a base part 13 and two yoke pieces 11, 12 formed by being erected and bent from the base part and a second member 10 having a base part 17 and two yoke pieces 14, 15 formed by being erected and bent from the base part are provided, a base body 18 is formed by arranging the base part of the first member and the base part of the second member in a laminated shape, and a first magnetic circuit 25 and a second magnetic circuit 26 are respectively formed by arranging optional two each of respective yoke pieces of the first member and the second member so as to face each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to the technical field of a two-axis actuator. More specifically, the present invention relates to a technical field of a two-axis actuator having two magnetic circuits, a first magnetic circuit and a second magnetic circuit.

[0002]

2. Description of the Related Art An optical pickup for reading an information signal recorded on a disk-shaped recording medium is provided with a biaxial actuator for performing focusing adjustment and tracking adjustment on the disk-shaped recording medium.
Some axis actuators have two magnetic circuits to improve the driving force of the objective lens.

FIG. 13 and FIG. 14 show an example of such a conventional two-axis actuator.

The biaxial actuator a includes, for example, a first member b and a second member c each made of an iron material, and the first member b is bent from the base portion d and the base portion d. Having a pair of yoke pieces e, e formed,
The second member c has a base portion f and a pair of yoke pieces g, g formed by being bent upright from the base portion f. The first member b and the second member c are arranged such that the yoke pieces e, e, g, and g form a line. Further, the yoke pieces e, g located outside each of the yoke pieces e, e, g, g have magnets h,
h is attached.

Accordingly, a first magnetic circuit i having yoke pieces e, e and a magnet h attached to one yoke piece e is formed on the first support member b, and the second support member c Is formed a second magnetic circuit j having yoke pieces g, g and a magnet h attached to one yoke piece g.

A leaf spring support member k is attached to one end of the second member c. Further, a coil bobbin l is arranged between the magnets h, h, and yoke pieces e, g to which the magnets h, h are not attached are inserted and positioned inside the coil bobbin l.

[0007] The coil bobbin 1 is provided with an objective lens m on the upper surface at the center. And the coil bobbin l
Has a focusing coil n and a tracking coil o
Are wound so that the winding directions are orthogonal to each other. The coil bobbin 1 is supported by wire-shaped leaf springs p, p,... Having one end supported by a leaf spring support member k.

In the biaxial actuator a constructed as described above, the first member b and the second member c are attached to the pickup base by screwing or the like, and the first member b and the second member c are attached to the pickup base. c constitutes a base body q.

In the biaxial actuator a, the objective lens m is operated in the focusing direction together with the coil bobbin l when the starting current is supplied to the focusing coil n, and the objective lens m together with the coil bobbin l is supplied when the starting current is supplied to the tracking coil o. The lens m is moved in the tracking direction.

[0010]

By the way, in the above-described conventional two-axis actuator a, the base body q is composed of the first member b and the second member c.
The reason why the base body q is provided separately in two parts is based on the reason that it is difficult to form two magnetic circuits from one member.

That is, as shown in FIG. 15, one member r
When the two magnetic circuits are to be formed from the following, when the yoke pieces e and g are formed by bending up, due to the board cutting,
This is because there is a problem that a portion required for forming both the yoke pieces e and g cannot be secured.

However, a conventional two-axis actuator a
When the base member q is provided separately from the first member b and the second member c as in
There is a problem in that positional accuracy is deteriorated, such as an increase in mounting error due to the separate mounting of the member b and the second member c.

Further, the first member b is provided on the pickup base.
And the second member c need to be separately mounted, so that there is also a problem that the mounting process is increased and the workability is deteriorated.

In order to solve such a problem, a yoke piece e of a portion which is inserted into the coil bobbin 1 by using a forging technique which uses a single member having a plate thickness larger than a predetermined thickness and uses a lot of shifting and crushing from this member. , G can be formed, but in this case, there is a problem that a mold for molding is extremely expensive, and expensive capital investment is required, and the production cost is extremely high. .

Therefore, the two-axis actuator of the present invention is:
It is an object of the present invention to overcome the above-mentioned problems and to form a two-axis actuator capable of ensuring good positional accuracy with respect to a pickup base at low cost.

[0016]

According to the present invention, there is provided a biaxial actuator comprising: a first member having a base portion and two yoke pieces formed to be bent from the base portion; And a second yoke having a base portion and two yoke pieces formed to be bent from the base portion.
And a base member of the first member and a base member of the second member are arranged in a stacked manner to form a base member.
The first magnetic circuit and the second magnetic circuit are respectively formed by arranging arbitrary two of the yoke pieces of the member and the second member so as to face each other.

Therefore, in the biaxial actuator of the present invention, it is not necessary to separately attach the first member and the second member to the pickup base.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a biaxial actuator according to an embodiment of the present invention.

First, the optical pickup will be described (see FIG. 1).

The optical pickup 1 includes a pickup base 2 on which necessary components are arranged. An integrated optical element 4 is attached to a side surface of the pickup base 2 via an adjustment seat 3. The integrated optical element 4 is formed by integrating required optical components such as a light emitting element and a light receiving element.

A raising mirror 5 is provided on the lower surface side of the pickup base 2, and a collimator lens 6 is mounted on the upper surface of the central portion. A two-axis actuator 8 is disposed on the upper surface of the pickup base 2 via an adjustment plate 7.

The laser light emitted from the light emitting element of the integrated optical element 4 is bent at a right angle by a rising mirror 5 and converted into a parallel light by a collimator lens 6 so that an objective lens of a biaxial actuator 8 described later is formed. The recording medium is irradiated toward the recording surface of the disk-shaped recording medium. Then, the return light reflected on the recording surface of the disk-shaped recording medium enters the light receiving element of the integrated optical element 4 via the objective lens, the collimator lens 6 and the rising mirror 5. The integrated optical element 4 detects the intensity of the return light and converts it into a predetermined electric signal.

At this time, the optical pickup 1 is moved in the radial direction of the disk-shaped recording medium, and the focusing adjustment and the tracking adjustment by the biaxial actuator 8 are performed.

Next, the two-axis actuator 8 will be described. The biaxial actuator 8 has a first base
(See FIGS. 2 to 6). In the following description, for the sake of convenience, the direction indicated by arrow F in each figure is described as forward, and the direction indicated by arrow B is described as rear.

First, the first member 9 will be described (see FIGS. 2 and 3).

The first member 9 is formed, for example, by stamping and bending a metal plate made of a plate-like iron material, and is formed by the following steps.

First, an intermediate 9 'having a predetermined shape is formed by punching a metal plate (see FIG. 2). A hole 9a having a predetermined shape is formed in the intermediate body 9 ', and a first rectangular projection 9b is formed so as to project forward so as to be located in the hole 9a. In the intermediate body 9 ', cutouts 9c, 9c are formed at the rear end and open rearward and are parallel to each other, and a portion between the cutouts 9c, 9c has a rectangular shape and protrudes rearward. 9d. Further, the intermediate body 9 'is formed with positioning holes 9e, 9e for positioning or mounting to the pickup base 2 and mounting screw holes 9f, 9f.

Next, the first intermediate body 9 'is bent by bending.
The first and second protruding pieces 9b and 9d are bent 90 ° toward each other, that is, the first protruding piece 9b is moved backward, and the second protruding piece 9d is bent forward by 90 °. The member 9 is formed (see FIG. 3). By bending the first projection 9b and the second projection 9d, the first yoke 11
And the second yoke piece 12 are formed, and the first yoke piece 11 and the second yoke piece 12 are located near the rear end.
A portion of the first member 9 other than the first yoke piece 11 and the second yoke piece 12 is formed as a base 13.

The base portion 13 of the first member 9 is formed by processing the intermediate member 9 'by a so-called crushing technique or the like so that the thickness of the first yoke piece 11 and the second yoke piece 12 is substantially half. (See FIG. 3).

Next, the second member 10 will be described (see FIGS. 4 and 5).

The second member 10 is made of the same material as the first member 9 and is formed by stamping and bending a metal plate. The second member 10 is formed by the following steps.

First, an intermediate 10 'having a predetermined shape is formed by punching a metal plate (see FIG. 4). In the intermediate body 10 ', a hole 10a having a predetermined shape is formed at a position corresponding to the hole 9a of the intermediate body 9', and a rectangular first protruding piece 10b is located at the hole 10a. It is formed so as to project rearward. The intermediate body 10 'has a notch 10c which is open rearward at the rear end. In the intermediate body 10 ', a second protruding piece 10d protruding forward is formed at the front end, and at a position corresponding to the positioning holes 9e, 9e of the intermediate body 9' and the mounting screw holes 9f, 9f, Positioning holes 10e, 10e and mounting screw holes 1 respectively
0f and 10f are formed. Further, the intermediate 10 '
Are formed with L-shaped projections 10g and 10g on both sides of the notch 10c.

Next, the first projecting piece 10b and the second projecting piece 10d of the intermediate body 10 'are brought closer to each other by bending, that is, the first projecting piece 10b is moved forward so that the second projecting piece 10b moves forward. Piece 10
The second member 10 is formed by bending 90 d backward so that the two oppose each other, and also bending a part of the protrusions 10 g and 10 g toward each other by 90 degrees (see FIG. 5). First
By bending the protruding piece 10b and the second protruding piece 10d, a first yoke piece 14 and a second yoke piece 15 are formed, respectively. The first yoke piece 14 and the second yoke piece 15 It is located near the front end. And the protrusion 10
g, 10 g of the positioning piece 1
6, 16 are formed. Further, a portion of the second member 10 other than the first yoke piece 14, the second yoke piece 15, and the positioning pieces 16, 16 is formed as a base portion 17.

The base portion 17 of the second member 10 is formed by processing the intermediate body 10 'by a so-called crushing technique or the like, so that the thickness of the first yoke piece 14 and the second yoke piece 15 is substantially half. (See FIG. 5).

The first member 9 and the second member 10 are formed as described above, and then the base member 18 is formed by using both (see FIG. 6).

The base member 18 is constructed by laminating the base member 13 of the first member 9 and the base member 17 of the second member 10 and joining them. At this time, the base portion 13 is stacked so as to be located above the base portion 17, and the first yoke piece 14 of the second member 10 is inserted through the hole 9 a of the first member 9 from below. Then, in the state where the base body 18 is formed in this way, the base portion 13 is formed.
And the base portion 17 are laminated on the main body base portion 19.
The holes 9a, 10a are positioned correspondingly on the upper and lower sides to form the transmission holes 20, and the positioning holes 9e, 10a
e, 9e, 10e and mounting screw holes 9f, 10f, 9f, 1
0f are located correspondingly, and the positioning holes 21,
21 and mounting screw holes 22, 22 are formed.

As described above, by forming the base portion 13 of the first member 9 and the base portion 17 of the second member 10 to be approximately half the thickness of the other portions, the main body base of the base body 18 is formed. The thickness of the portion 19 is substantially the same as the thickness of the first yoke pieces 11, 14 and the second yoke pieces 12, 15, and the main body base portion 19 does not become unnecessarily thick. Therefore,
The arrangement space for the pickup base 2 is made more efficient, and the thickness of the optical pickup 1 can be reduced.

Further, in the base body 18, the first yoke piece 11, the second yoke piece 12, and a portion connecting both of them, and the first yoke piece 14 and the second yoke piece 14,
Each yoke is constituted by the yoke piece 15 and the portion connecting these two pieces.
The thickness of the portion connecting the first and second yoke pieces 12 and the thickness of the portion connecting the first yoke piece 14 and the second yoke piece 15 are such that the first yoke piece 1
It is desirable that the thickness of each of the first and second yoke pieces 12 and 15 be equal to or greater than the thickness of each of the first and second yoke pieces 12 and 15.

The base body 18 is provided with predetermined members, thereby constituting the biaxial actuator 8 (see FIG. 1).

The first yoke piece 11 of the second yoke piece 12
The surface of the second yoke piece 15 facing the first yoke piece 14 and the face of the second yoke piece 15
3, 24 are attached. As a result, a magnetic circuit 25 having the first yoke piece 11, the second yoke piece 12, and the magnet 23 is formed.
4. A magnetic circuit 26 having the second yoke piece 15 and the magnet 24 is formed.

A leaf spring support member 27 is attached to the rear end of the base body 18 so as to be inserted between the second yoke piece 12 and the positioning pieces 16, 16.

A coil bobbin 28 is disposed between the magnets 23 and 24, and the first yoke piece 11 and the first yoke piece 14 are inserted and positioned inside the coil bobbin 28, respectively.

An object lens 29 is provided on the upper surface of the coil bobbin 28 at the center. A focusing coil 30 and a tracking coil 31 are wound around the coil bobbin 28 so that the winding directions are orthogonal to each other. In addition, the coil bobbin 28 has a wire-shaped leaf spring 32, one end of which is supported by the leaf spring support member 27,
... supported.

As described above, the two-axis actuator 8
The biaxial actuator 8 is disposed on the upper surface of the central portion of the pickup base 2 via the adjustment plate 7 as described above. At this time, the positioning of the biaxial actuator 8 with respect to the pickup base 2 is performed using the positioning holes 21, 21 of the base body 18, and mounting is performed by inserting mounting screws (not shown) into the mounting screw holes 22, 22. .

In the two-axis actuator 8, when the starting current is supplied to the focusing coil 30, the objective lens 29 is operated in the focusing direction together with the coil bobbin 28, and when the starting current is supplied to the tracking coil 31, the objective lens 29 is supplied with the coil bobbin 28. The objective lens 29 is operated in the tracking direction.

Therefore, the coil bobbin 28 and the objective lens 29 provided thereon constitute a movable block 100, and the base body 18 and the leaf spring supporting member 27 attached to the base body 18 constitute a fixed block 200.

As described above, in the two-axis actuator 8, the base member 18 formed by laminating the first member 9 and the second member 10 is attached to the pickup base 2, so that the conventional two-axis actuator 8 has the same structure. Compared with the case where the two separated members are separately mounted on the pickup base 2, the positional accuracy can be improved, and the number of mounting steps can be reduced, so that the workability can be improved.

Further, since the base body 18 can be easily formed without using a costly forging technique using the approach and crushing, the cost of the biaxial actuator 8 can be reduced.

Further, in the biaxial actuator 8, the first member 9 in which the first magnetic circuit 25 is integrally formed is formed.
And the second magnetic circuit 26 is formed using a part of the integrally formed second member 10, so that the formed magnetic circuits 25 and 26 are high. It is a performance and a good performance of the biaxial actuator 8 can be secured.

In the above description, when the first member 9 and the second member 10 are laminated to form the base member 18, the first member 9 and the second member 10 are stacked.
The base portion 13 of the member 9 is replaced with the base portion 1 of the second member 10.
7, but on the contrary, the base 13 of the first member 9 is connected to the base 17 of the second member 10.
May be located below.

Next, a first modified example of the base body will be described. Similarly to the base body 18, the base body 18A of the first modified example has two members, namely, the first member 18A.
And the second member 34 are laminated (see FIGS. 7 to 11). In the following description, a direction indicated by an arrow F in each drawing is referred to as a front, and a direction indicated by an arrow B is referred to as a rear for convenience.

First, the first member 33 will be described (see FIGS. 7 and 8).

The first member 33 is formed by, for example, punching and bending a metal plate made of a plate-like iron material, and is formed by the following steps.

First, an intermediate body 33 'having a predetermined shape is formed by punching a metal plate (see FIG. 7). A hole 33a having a predetermined shape is formed in the intermediate body 33 '.
The first protrusion 33b having a rectangular shape so as to be located in the hole 33a.
Are formed so as to project rearward. And
The intermediate body 33 ′ is formed with parallel cutouts 33 c, 33 c which are open rearward at the rear end thereof.
The portion between 33c is rectangular and is formed as a second protruding piece 33d that protrudes rearward. Further, the positioning holes 33e, 33e and the mounting screw holes 33f, 33
f is formed.

Next, the first projection 33b and the second projection 33d of the intermediate body 33 'are each bent 90 degrees forward by bending to form the first member 33 (see FIG. 8). . By bending the first protruding piece 33b and the second protruding piece 33d, the first yoke piece 35 and the second
The first yoke piece 35 is located near the front end, and the second yoke piece 36 is located near the rear end. A portion of the first member 33 other than the first yoke piece 35 and the second yoke piece 36 is formed as a base portion 37.

The base portion 37 of the first member 33 has a thickness similar to that of the base portion 13 of the first member 9 by a so-called crushing technique or the like. (See FIG. 8).

Next, the second member 34 will be described (see FIGS. 9 and 10).

The second member 34 is made of the same material as the first member 33, and is formed by stamping and bending a metal plate, and is formed by the following steps.

First, an intermediate body 34 'having a predetermined shape is formed by punching a metal plate (see FIG. 9). The intermediate body 34 'is formed with a hole 34a having a predetermined shape at a position corresponding to the hole 33a of the intermediate body 33'.
Is formed so that the first protrusion 34b of a rectangular shape projects forward. And intermediate 3
4 'is formed with a cutout portion 34c which is opened rearward at the rear end. Further, a second protruding piece 34d protruding forward is formed at the front end of the intermediate body 34 '.
3 'positioning holes 33e, 33e and mounting screw holes 33f, 3
3f, the positioning holes 34e,
34e and mounting screw holes 34f, 34f are formed. Further, the intermediate body 34 'is formed with L-shaped projections 34g, 34g on both sides of the notch 34c.

Next, the first protruding piece 34b and the second protruding piece 34d of the intermediate body 34 'are bent backward by 90 °, respectively, and a part of the protruding parts 34g, 34g are brought closer to each other by bending. The second member 34 is formed by being bent 90 ° in the direction (see FIG. 10). By bending the first protrusion 34b and the second protrusion 34d, a first yoke 38 and a second yoke 39 are formed, respectively, and the first yoke 38 is positioned near the rear end. And the second yoke piece 3
9 is located near the front end. And the projections 34g, 34
The positioning pieces 40, 40 are formed by bending a part of g.
Is formed. In addition, the first yoke piece 38, the second yoke piece 39, and the positioning pieces 40, 4 of the second member 34
A portion other than 0 is formed as the base portion 41.

The base portion 41 of the second member 34 is formed with a first yoke piece 38 and a second yoke piece 39 by a so-called crushing technique similarly to the base portion 17 of the second member 10.
(See FIG. 10).

As described above, the first member 33 and the second
Is formed, and then the base member 18 is formed using both members.
A is formed (see FIG. 11).

The base body 18A is formed by laminating the base portion 37 of the first member 33 and the base portion 41 of the second member 34 and joining them. At this time, the base portions 37 are stacked so as to be located above the base portion 41, and the first yoke piece 38 of the second member 34 is inserted through the hole 33a of the first member 33 from below. Then, in the state where the base body 18A is formed in this manner,
A portion where the base portion 37 and the base portion 41 are stacked is formed as a main body base portion 42, and the holes 33a and 34a are vertically positioned to form a transmission hole 43, and positioning holes 33e, 34e, and 33e are formed. , 34e and mounting screw hole 33
f, 34f, 33f, 34f are positioned correspondingly, and positioning holes 44, 44 and mounting screw holes 45, 45 are formed respectively.

In the base member 18A, the first member 3
The first magnetic circuit having the second yoke piece 36 and the first yoke piece 38 in which the third second yoke piece 36 and the first yoke piece 38 of the second member 34 are located opposite to each other. Are formed, and the first yoke piece 35 of the first member 33 and the second
A second magnetic circuit having the first yoke piece 35 and the second yoke piece 39 is formed by opposing the second yoke piece 39 of the member 34.

The base body 18 formed as described above
A two-axis actuator in which required members are provided in A is disposed on the upper surface of the central portion of the pickup base 2 via an adjustment plate 7.

Even when the above-mentioned base body 18A is used as a component part of a two-axis actuator, the positional accuracy is improved as compared with the conventional case where two separated members are separately attached to the pickup base 2. In addition, the number of mounting steps can be reduced, and workability can be improved.

Further, since the base body 18A can be easily formed without using a costly forging technique using the approach and crushing, the cost of the biaxial actuator can be reduced.

In the above description, when the first member 33 and the second member 34 are laminated to form the base body 18A,
Although the base 37 of the first member 33 is positioned above the base 41 of the second member 34, on the contrary,
The base 37 of the first member 33 may be located below the base 41 of the second member 34.

Next, a second modification of the base body will be described. Similarly to the base body 18, the base body 18B of the second modified example has two members, namely, the first member 18B.
And the second member 47 are laminated (see FIG. 12). In the following description, a direction indicated by an arrow F in each drawing is referred to as a front, and a direction indicated by an arrow B is referred to as a rear for convenience. The configuration of the base body 18B will be mainly described.

The first member 46 is formed, for example, by stamping and bending a metal plate made of a plate-like iron material. The first member 46 has a first yoke piece 48 and a second yoke piece 49 which are formed by being bent by 90 ° in a direction approaching each other. The first yoke piece 48 and the second yoke piece The portion other than 49 is the base portion 50
It is formed as. Then, the first yoke piece 48 is located near the front end of the base portion 50 and the second yoke piece 4
9 is located near the rear end of the base portion 50. Also,
The base portion 50 of the first member 46 is formed to a thickness approximately half the thickness of the first yoke piece 48 and the second yoke piece 49 by a technique such as so-called crushing.

The second member 47 is made of the same material as the first member 46, and is formed by punching and bending a metal plate having a longer length in the front-rear direction than the first member 46. is there. The second member 47 has a first yoke piece 51 and a second yoke piece 52 which are formed by being bent by 90 ° in directions approaching each other, and is formed by being bent upright at the rear end. It has positioning pieces 53, 53.
A portion of the second member 47 other than the first yoke piece 51, the second yoke piece 52, and the positioning pieces 53, 53 is formed as a base portion.

The first yoke piece 51 is located near the front end of the base portion 54, and the second yoke piece 52 is located near the rear end of the base portion 54. The base portion 54 of the second member 47 is formed to a thickness approximately half the thickness of the first yoke piece 51 and the second yoke piece 52 by a technique such as so-called crushing.

The base member 50 of the first member 46 is laminated on the base member 54 of the second member 47, and the first member 46 and the second member 47 are joined to form the base member 18B.
When the first member 46 and the second member 47 are joined, the first yoke piece 48 of the first member 46 and the first yoke piece 51 of the second member 47 are arranged to face each other. And the second yoke piece 49 of the first member 46 and the second yoke piece 52 of the second member 47 are arranged to face each other. Then, in a state where the base body 18B is formed in this manner, a portion where the base portion 50 and the base portion 54 are stacked is formed as the main body base portion 55.

A transmission hole 56 is formed in a portion between the first yoke piece 48 and the second yoke piece 49 in the main body base portion 55 of the base body 18B. In addition, base body 1
Positioning holes 57, 57 and mounting screw holes 58, 58 are formed at predetermined positions in the body base portion 55 of 8B.

In the base member 18B, the first member 4
6, a first magnetic circuit having the first yoke piece 48 of the sixth member and the first yoke piece 51 of the second member 47 is formed.
The second yoke piece 49 of the first member 46 and the second member 47
A second magnetic circuit having the second yoke piece 52 is formed.

The base body 18 formed as described above
A two-axis actuator, in which required members are provided on B, is disposed on the upper surface of the central portion of the pickup base 2 via an adjustment plate 7.

Even when the base member 18B is used as a component of a two-axis actuator, the positional accuracy is improved as compared with the conventional case where two separated members are separately mounted on the pickup base 2. In addition, the number of mounting steps can be reduced, and workability can be improved.

Further, since the base body 18B can be easily formed without using a costly forging technique using the approach and crushing, the cost of the biaxial actuator can be reduced.

It should be noted that the specific shapes and structures of the respective parts shown in the above-described embodiments are merely examples of the embodiment of the present invention, and the present invention is not limited thereto. Should not be construed as limiting the technical scope of the present invention.

[0080]

As is apparent from the above description, the biaxial actuator of the present invention has two magnetic circuits, a first magnetic circuit and a second magnetic circuit, and has a movable object having an objective lens on a base body. A biaxial actuator comprising a block and a support for supporting the movable block, comprising: a first member having a base portion and two yoke pieces formed to be bent from the base portion; A second member having a portion and two yoke pieces formed to be bent from the base portion, wherein the base portion of the first member and the base portion of the second member are arranged in a laminated manner. To form the base body, and any two of the yoke pieces of the first member and the second member are arranged so as to face each other, and the first magnetic circuit and the second magnetic circuit are respectively provided. Characterized by the formation of To.

Accordingly, the base member formed by laminating the first member and the second member is attached to the pickup base, which is different from the conventional case where two separate members are separately attached to the pickup base. However, the position accuracy can be improved, and the number of mounting steps can be reduced, so that the workability can be improved.

Further, since the base body can be easily formed without using a high-cost forging technique using shifting and crushing, the cost of the biaxial actuator can be reduced.

According to the second aspect of the present invention, the first
Since the first magnetic circuit is formed using the two yoke pieces of the second member and the second magnetic circuit is formed using the two yoke pieces of the second member, each formed magnetic circuit has high performance. Thus, good performance of the two-axis actuator can be secured.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a biaxial actuator of the present invention together with FIG. 2 to FIG. 12, and this figure is an exploded perspective view of an optical pickup.

FIG. 2 is an enlarged perspective view showing an intermediate body of a first member.

FIG. 3 is an enlarged perspective view showing a first member.

FIG. 4 is an enlarged perspective view showing an intermediate body of a second member.

FIG. 5 is an enlarged perspective view showing a second member.

FIG. 6 is an enlarged perspective view showing a base body.

7 shows a first modification of the base body together with FIGS. 8 to 11, and is an enlarged perspective view showing an intermediate body of the first member. FIG.

FIG. 8 is an enlarged perspective view showing a first member.

FIG. 9 is an enlarged perspective view showing an intermediate body of the second member.

FIG. 10 is an enlarged perspective view showing a second member.

FIG. 11 is an enlarged perspective view showing a base body.

FIG. 12 is an enlarged perspective view showing a second modification of the base body.

FIG. 13 is an enlarged perspective view showing a conventional two-axis actuator.

FIG. 14 is an enlarged perspective view showing a conventional base body.

FIG. 15 is an enlarged perspective view showing one of conventional problems.

[Explanation of symbols]

8 Biaxial actuator, 9 First member, 10 Second member, 11 First yoke piece (yoke piece), 12
Second yoke piece (yoke piece), 13... Base part, 14.
First yoke piece (yoke piece), 15: second yoke piece (yoke piece), 17: base portion, 18: base body, 25
.. A first magnetic circuit, 26 a second magnetic circuit, 27 a leaf spring support member (support), 29 an objective lens, 100 a movable block, 33 a first member, 34 a second member, 3
5: First yoke piece (yoke piece), 36: second yoke piece (yoke piece), 37: base portion, 38: first yoke piece (yoke piece), 39: second yoke piece (yoke) Piece),
41 ... base part, 18A ... base body, 46 ... first member, 47 ... second yoke piece (yoke piece), 49 ... second yoke piece (yoke piece), 50 ... Base part, 51... First yoke piece (yoke piece), 52.
Yoke pieces (yoke pieces), 54 ... base part, 18B ... base body

Claims (2)

[Claims] 1. A two-axis actuator comprising a first magnetic circuit and a second magnetic circuit, a movable block having an objective lens on a base body, and a support for supporting the movable block. A base portion and 2 formed by being bent upright from the base portion.
A first member having two yoke pieces, a base portion, and a second member formed by being bent upright from the base portion.
A second member having two yoke pieces; a base member of the first member and a base member of the second member are arranged in a layered manner to form the base member; A two-axis actuator, wherein arbitrary two of the two yoke pieces of the two members are arranged to face each other to form the first magnetic circuit and the second magnetic circuit, respectively. 2. A first magnetic circuit is formed by using two yoke pieces of a first member, and a second magnetic circuit is formed by using two yoke pieces of a second member. The two-axis actuator according to claim 1.