JPH08124194A - Biaxial actuator - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a biaxial actuator in which wiring for energizing a driving means for driving a movable part with respect to a fixed part can be easily performed and the number of parts can be reduced. A fixed part, a movable part 2 to which an objective lens is attached, and an elastic support part 4 for supporting the movable part 2 relative to the fixed part 40 so as to be movable at least in the optical axis direction of the objective lens 2a.
a to 4d, driving means 3a and 3b for driving the movable portion 2 relative to the fixed portion 40, and soldering to the elastic supporting portions 4a to 4d, for supplying power to the driving means 3a and 3b. A flexible printed circuit board FPC, and a biaxial actuator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biaxial actuator used in an optical disk device for reproducing information from an information recording medium or recording information on the information recording medium,
In particular, the present invention relates to a biaxial actuator having an elastic support portion and a flexible substrate for energization.

[0002]

2. Description of the Related Art FIGS. 4 and 5 show a biaxial actuator of an optical disk device for reproducing a compact disk, for example. This conventional biaxial actuator
The movable portion 10 has a fixed portion 101 and a movable portion 102.
2 is movable with respect to the fixed portion 101 along the focus direction FCS and the tracking direction TRK.

The movable portion 102 has an objective lens 103. The focus driving coil 104 includes the movable unit 102.
For driving along the focus direction FCS. The tracking coil 105 connects the movable portion 102 to the T
It is for moving along the RK direction. These focus driving coil 104 and tracking coil 10
In order to supply power to the battery 5, there are two kinds of flexible printed boards 106 for power supply and flexible printed board 107 for power supply. The energizing flexible printed board 106 is provided between the movable portion 102 and the fixed portion 101. The flexible printed board 107 for power supply is
An end portion 106a of the flexible printed board 106 for energization
It is designed to be electrically connected by soldering.

[0004]

As described above, in the conventional biaxial actuator, it is necessary to solder the two types of flexible printed boards 106 and 107 to each other. The flexible printed board 106 for energization must be provided so as to bridge between the fixed portion 101 and the movable portion 102. Therefore, the flexible printed circuit board 1
There is a problem that the setting workability of 06 and 107 is poor, and the number of parts is large and the cost is high.

Therefore, the present invention has been made in order to solve the above-mentioned problems, and wiring for energizing driving means for driving a movable part with respect to a fixed part can be easily performed.
Moreover, it is an object of the present invention to provide a biaxial actuator that can reduce the number of parts.

[0006]

According to the present invention, the above object is a biaxial actuator used in an optical disk device for reproducing information from an information recording medium or recording information on the information recording medium, A fixed part, a movable part to which the objective lens is attached, an elastic support part for movably supporting the movable part with respect to the fixed part in at least the optical axis direction of the objective lens, and the movable part on the fixed part. This is achieved by a biaxial actuator that includes driving means for driving the driving means and a flexible printed circuit board that is soldered to the elastic support portion and supplies power to the driving means. In the present invention, preferably, with respect to the end portion fixed to the fixed portion side of the elastic support portion,
The land at the end of the flexible board for power supply is soldered. In the present invention, the elastic support portion is preferably a leaf spring.

[0007]

According to the above structure, the flexible printed circuit board is simply soldered to the elastic supporting portion,
The electric setting can be easily performed and power can be supplied to the driving means. By the operation of the driving means, the movable part moves at least in the optical axis direction of the objective lens with respect to the fixed part. In the present invention, preferably, the land of the end portion of the flexible substrate for power feeding is soldered to the end portion fixed to the fixing portion side of the elastic support portion.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The examples described below are
Since it is a preferred specific example of the present invention, various technically preferable limitations are attached, but the scope of the present invention is, unless otherwise stated to limit the present invention, in the following description.
It is not limited to these modes.

FIG. 1 is a perspective view showing an embodiment of a biaxial actuator of the present invention, and FIG. 2 is an exploded perspective view of the biaxial actuator. This biaxial actuator is used for an optical pickup. An optical pickup is used to reproduce or record information signals on an optical disc, for example, a so-called compact disc (CD) or a magneto-optical disc. This optical pickup includes a semiconductor laser as a light source, an objective lens, an optical system, and a photodetector. The light beam emitted from the semiconductor laser is focused on the recording surface of the optical disc by the objective lens through the optical system.

The light beam reflected from the optical disk is separated from the light beam emitted from the semiconductor laser by the optical system and guided to the photodetector. The light beam emitted from the semiconductor laser follows the displacement of the optical disc in the direction orthogonal to the surface direction of the optical disc caused by the warp of the optical disc, etc., and is focused on the recording surface of the optical disc. The position of the objective lens in the optical axis direction is adjusted to the focus direction in FIG. At the same time, if necessary, the position of the spot of the light beam emitted from the semiconductor laser on the optical disc is aligned with the optical axis of the objective lens D so as to follow the eccentricity of the optical disc D and the meandering of the track formed on the optical disc D. The position in the orthogonal direction is adjusted to the tracking direction.

As described above, in adjusting the focus position of the light beam emitted from the semiconductor laser and the spot position on the recording surface of the optical disc, the objective lens is orthogonal to the position of the objective lens in the optical axis direction and the optical axis. This is done by adjusting the directional position. An electromagnetically driven actuator is used to adjust the position of the objective lens and is also called a biaxial actuator or an objective lens actuator.

In FIGS. 1 and 2, the biaxial actuator 1 has a movable portion 2 and a fixed portion 40. The biaxial actuator 1 includes a lens holder 2, a coil bobbin 3, a plurality of elastic supports 4a, 4b, 4c, 4d, a base 5 and a mounting portion 6. The lens holder 2 has an opening for mounting the coil bobbin 3 and a recess for mounting the objective lens 2a. A hole through which a light beam emitted from the semiconductor laser or a return beam from the recording surface of the optical disk passes is formed on the bottom surface of this recess. The objective lens 2a is attached to the concave portion of the lens holder 2b by adhesion or the like. The lens holder 2 includes a plurality of elastic supports 4a, 4b, 4c, 4d.
Is movably supported in the focus direction FCS and the tracking direction TRK.

The coil bobbin 3 is formed with an opening into which a magnetic circuit of a base 5 described later is inserted, and
A focus coil 3a and a plurality of tracking coils 3b, 3b are attached. Focus coil 3
A is wound around the bobbin 3 along an axis parallel to the optical axis of the objective lens 2a. Tracking coils 3b, 3b
Is formed by winding a coil in an elliptical shape or a rectangular shape, and is attached to one side surface of the focus coil 3a. The upper surface of the coil bobbin 3 has a cover 3
covered by c. The coil bobbin 3 is attached to the opening formed in the lens holder 2b with the focus coil 3a and the tracking coils 3b and 3b attached. The movable part 2 includes a coil bobbin 3, a lens holder 2b, an objective lens 2a, and the like. On the other hand, the fixed portion 40 includes the base 5, the yoke portions 8a and 8b, the permanent magnet 9, the mounting portion 6, the protruding portion 7, and the like.

A plurality of elastic supports 4a, 4b, 4c, 4d
Is formed of an elastic body such as a leaf spring, and between the lens holder 2b of the movable portion 2 and the mounting portion 6 of the fixed portion 40,
They are attached by a technique such as adhesion and soldering so that they are parallel to each other. The base 5 is formed with a protruding portion 7 to which the attaching portion 6 is attached and a pair of opposing yoke portions 8a and 8b forming a magnetic circuit.

With the lens holder 2b and the mounting portion 6 connected by a plurality of elastic supports 4a to 4d,
The attachment portion 6 is attached to the protrusion 7 by a method such as adhesion. At this time, the attaching portion 6 is attached to the protruding portion 7 so that the optical axis of the objective lens 2a does not tilt. A permanent magnet 9 is attached to the surface of the yoke portion 8b facing the yoke portion 8a. A magnetic circuit is constituted by the pair of yoke portions 8a and 8b and the permanent magnet 9.

With the mounting portion 6 attached to the protruding portion 7, the focus coil 3a and the tracking coils 3b and 3b attached to the coil bobbin 3 are inserted into the gap between the permanent magnet 9 and the one yoke portion 8a. It
At the same time, the other yoke portion 8b and the permanent magnet 9 are inserted into the opening of the coil bobbin 3.

In the biaxial actuator 1 thus constructed, the focus coil 3a and the tracking coils 3b, 3b are supplied with currents based on the focus servo signal and the tracking servo signal, respectively.
It is necessary to supply each through the current supply path described below. As a result, the lens holder 2b, that is, the objective lens 2a is driven in the focus direction FCS and the tracking direction TRK by the DC magnetic field of the magnetic circuit and the alternating magnetic field generated from the focus coil 3a and the tracking coils 3b and 3b.

Next, the current supply path will be described. The four elastic supports 4a, 4b, 4c and 4d described above are connected to the connection terminals 24a, 24 as shown in FIGS.
b, 24c and 24d, respectively. The connection terminals 24a to 24d are fixed parts 6 also called attachment parts.
It is provided so as to project rearward from. Each elastic support portion 4a to 4d is already electrically connected to the above-described focus coil 3a and the plurality of tracking coils 3b and 3b. The elastic support portions 4a to 4d are also referred to as plate-like suspensions, and can be made of, for example, conductive phosphor bronze, beryllium copper, SUS, or the like. The lens holder 2b of the movable portion 2 can be made of PPS (polyphenylene sulfide), polycarbonate, or the like, for example.

Flexible printed circuit board FPC of FIG.
Has four lands 30, 32, 34, 36. The lands 30 to 36 correspond to the connection terminals 24a to 24d, respectively. The other end of the flexible printed circuit board FPC is connected to the drive control unit 45. The land 30 of the flexible printed circuit board FPC is
It is connected to the connection terminal 24a by soldering. Similarly, the land 32 is connected to the connection terminal 24b by soldering. The land 34 is connected to the connection terminal 24c by soldering. The land 36 is the connection terminal 24.
It is connected to d by soldering. As a result, the current from the drive control unit 45 is applied to the flexible printed circuit board FP.
C, the lands 30 to 36, the connection terminals 24a to 24d, and the elastic support portions 4a to 4d, the focus coil 3a or the tracking coil 3b,
Power can be supplied to 3b. For example, the elastic support portions 4a and 4c are used for supplying power to the focus coil 3a, and
b and 4d supply power to the tracking coils 3b and 3b.

In the above-described embodiment, the lands 30 to 36 of the flexible printed circuit board FPC are only once soldered to the four connection terminals 24a to 24d, and the drive control section 40 causes the focus coil 3a and the tracking coil 3b. , 3b can be selectively fed. As a result, the objective lens 2a in FIG.
Focus direction FCS or tracking direction TRK
Can be driven along. It is only necessary to use one flexible printed circuit board FPC to energize the coil bobbin 3 of the fixed part from the fixed part 6 side, and the energization from the fixed part 40 side to the movable part 2 side is performed by the elastic support part 4a. Or, 4d is used. Therefore, it is not necessary to separately set a flexible printed circuit board between the fixed portion 40 side and the movable portion 2 as in the conventional case, workability is improved, and the number of parts can be reduced. Therefore, it is possible to reduce the manufacturing cost of the biaxial actuator of the embodiment of the present invention.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, an example using four plate-shaped elastic support portions 4a to 4d is shown. The present invention is not limited to this, and the present invention can be applied to the case where, for example, two elastic supporting portions are used, or when elastic supporting portions having other shapes are used. Further, in the above-described embodiment, the optimum biaxial actuator is mainly described for the optical disc for recording and reproducing the compact disc. Not limited to this, the biaxial actuator of the present invention can be applied to, for example, an optical pickup of an optical disk device for recording / reproducing on / from a magneto-optical disk.

[0022]

As described above, according to the present invention, the wiring for energizing the driving means for driving the movable portion with respect to the fixed portion can be easily performed, and the number of parts can be reduced. it can.

[Brief description of drawings]

FIG. 1 is a perspective view showing a preferred embodiment of a biaxial actuator of the present invention.

FIG. 2 is an exploded perspective view of the biaxial actuator shown in FIG.

FIG. 3 is a perspective view showing a manner of soldering a connection terminal on the fixed portion side of the biaxial actuator of FIG. 1 and a land of a flexible printed board.

FIG. 4 is a plan view showing an example of a conventional biaxial actuator.

5 is a side view showing the conventional biaxial actuator of FIG.

[Explanation of symbols]

 2 movable part 2a objective lens (movable part) 2b lens holder (movable part) 3 coil bobbin (movable part) 3a focus coil (driving means) 3b tracking coil (driving means) 4a to 4d elastic support part (suspension) 40 fixed part FPC Flexible printed circuit board

Claims (3)

[Claims] 1. A biaxial actuator used in an optical disk device for reproducing information from an information recording medium or recording information on the information recording medium, the fixed part, a movable part to which an objective lens is attached, and the fixed part. An elastic support portion that supports the movable portion with respect to the movable portion at least in the optical axis direction of the objective lens; drive means for driving the movable portion with respect to the fixed portion; A flexible printed circuit board, which is soldered to the driving means, for supplying electric power to the driving means. 2. The biaxial actuator according to claim 1, wherein the land of the end portion of the flexible substrate for power feeding is soldered to the end portion of the elastic support portion fixed to the fixed portion side. 3. The elastic supporting portion is a leaf spring.
Alternatively, the biaxial actuator according to claim 2.