JPH06267089A - Apparatus for driving objective lens - Google Patents

Abstract

PURPOSE:To uniformly and tightly wind wires constituting a driving coil by an automatic machine, and to easily connect the wires with a supporting wire for suspending a lens holder. CONSTITUTION:A bobbin 4 is formed to wind a wire in a manner that the sectional area of the wire constituting a driving coil 6 is gradually increased from a starting end to a terminal end of winding. Supporting wires 12 each for suspending a lens holder 1 to a supporting frame 11 in a shiftable fashion are coupled at coupling parts 16 of the bobbin 4. A starting end and a terminal end of the wire constituting the driving coils 6, 7 are hooked to the predetermined coupling parts 16.

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 device for driving an objective lens in an optical pickup device for reading a signal from a medium using a light beam or writing a signal in the medium.

[0002]

2. Description of the Related Art As is well known, an objective lens driving device provided in an optical pickup device for reading a signal from a medium such as a disk using a light beam or writing a signal in the medium is a magnetic field generated by a magnetic circuit. And a lens holder to which a drive coil is attached in the magnetic field is arranged to movably support the frame, and the relationship between the direction of the current flowing through the drive coil and the direction of the magnetic flux passing through the drive coil. The driving coil and the magnetic circuit are set so that the lens holder, that is, the objective lens, can be driven in a predetermined direction.

As such an objective lens driving device,
For example, as disclosed in Japanese Patent Laid-Open No. 3-91122, the objective lens is arranged so as to be offset from the lens holder, a space is secured in the central portion of the lens holder, and the drive coil is solidified into an air-core structure so that the inside of the space is reduced. It is known that a drive coil and a magnetic circuit are arranged in the device to reduce the thickness.

As the objective lens driving device, for example, as disclosed in Japanese Utility Model Publication No. 4-19615, a lens holder is displaceably supported on a frame serving as a support frame by four conductive support wires, 2. Description of the Related Art There is known an objective lens driving device configured to apply a control signal to a focusing coil and a tracking coil that form a drive coil using a support wire. Further, in this objective lens driving device, respective connecting portions for connecting the respective support wires are provided on upper and lower surfaces on both right and left sides of the objective lens of the lens holder depending on the installation position of the respective support wires. A control signal is supplied to the focusing coil and the tracking coil by relaying the respective coupling portions and energizing the respective support wires.

[0005]

By the way, in order to arrange the drive coil and the magnetic circuit in the space provided in the center of the lens holder, as described above, the drive coil (focusing coil and tracking coil) is taken into consideration in consideration of the arrangement of the magnetic circuit. Since it had an air core structure that hardened the coil itself,
There is a problem in workability because the wound drive coils must be manually bonded and integrated, and the integrated drive coils must be positioned and bonded to the lens holder using a jig. .

In order to energize the drive coil, it is necessary to electrically connect the starting end and the terminating end of the wire forming the drive coil to predetermined supporting wires, respectively. To perform the connection, the wire for the drive coil is used. Had to be manually entangled in a predetermined joint portion of the lens holder and soldered to the joint portion together with a predetermined supporting wire, which also caused a problem in workability.

On the other hand, in a general objective lens driving device in which a driving coil is mounted around a lens holder, a spindle is wound around the bobbin by an automatic machine using the lens holder as a bobbin, or a wire is orbited around the bobbin. The wire forming the drive coil is wound by the flyer winding. In this case, the winding pitch of the wire is controlled by sliding the bobbin or the wire slightly, but since the wire diameter is thin and the pitch is very small,
Pitch control is difficult, and there has been a problem that adjacent wires often overlap unevenly or are separated from each other.

[0008]

DISCLOSURE OF THE INVENTION The present invention is an objective lens driving device made in view of the above-mentioned problems, in which a wire constituting a drive coil is wound from a winding start end side to a winding end side. A bobbin around which the wire is wound is formed so that the cross-sectional area gradually increases.

Further, each bobbin is provided with a connecting portion for connecting each supporting wire for suspending the lens holder to the supporting frame so as to be displaceable, and the starting end and the terminating end of the wire forming the drive coil are engaged with the predetermined connecting portion. I'm trying to stop.

[0010]

According to the present invention, the bobbin is formed so that the cross-sectional area of the portion around which the wire constituting the drive coil is wound gradually changes, and the wire is wound from the smaller cross-sectional area toward the larger one. The wire to be wound by being brought into close contact with the adjacent wire on the winding start end side.

Further, even if the bobbin for winding the drive coil is provided separately from the lens holder and the drive coil is arranged at the center of the lens holder, the drive coil can be formed by using an automatic machine. In addition, each bobbin is provided with each coupling part for coupling each support wire for hanging to the support frame, and the start end and the end of the wire forming the drive coil are locked to the predetermined coupling part. .

[0012]

1 is a plan view showing a completed assembled state of an objective lens driving device according to the present invention. In FIG. 1, reference numeral 1 is a lens holder made of synthetic resin in which the objective lens 2 is mounted at an offset position.
As shown in the developed plan view of FIG. 2, a space 3 is formed in the central portion.

The winding center axis 4 is wound in the direction orthogonal to the optical axis of the objective lens 2, and a pair of tracking coils 6 are wound around the hole 5 formed in the center so as to be divided into two. It is a bobbin made of synthetic resin to which a focusing coil 7 wound with its central axis aligned with the optical axis direction of the objective lens 2 is attached. The bobbin 4 is arranged near the objective lens 2 in the space 3 of the lens holder 1 while the tracking coil 6 and the focusing coil 7 are wound.

A permanent magnet 8 is arranged in the space 3, one magnetic pole surface of which is arranged to face a predetermined surface of the bobbin 4 in which the tracking coils 6 and the focusing coil 7 are arranged orthogonally to each other, and 9 is a permanent magnet. The permanent magnet 8 is arranged in the space 3.
The outer yoke 10 provided with the other magnetic pole surface of the bobbin 4 is formed so as to be connected to the outer yoke 9 and
The inner yoke is inserted and arranged in the hole 5 of FIG.
The permanent magnet 8, the outer yoke 9 and the inner yoke 10 are
A magnetic circuit that generates a magnetic flux penetrating a predetermined portion of each tracking coil 6 and focusing coil 7 is configured.

Reference numeral 11 denotes a frame, which is a frame and is integrally formed with the outer yoke 9 and the inner yoke 10 by cutting and bending by press working using a magnetic metal plate such as a cold rolled steel plate (SPC). Has been done.

Reference numeral 12 is a support wire for suspending the lens holder 1 so as to be displaceable with respect to the frame 11. The support wires 12 are provided above and below the lens holder 1 on both left and right sides of the objective lens 2 of the lens holder 1, and the four support wires 12 are provided.
Are fixed by soldering to a printed circuit board 13 each having one end screwed to a predetermined side surface of the frame 11, and the other end is made of a synthetic resin supporting member 14 screwed to a predetermined side surface of the frame 11. It is installed by being inserted into the hole 15 formed corresponding to the position of each support wire 12. The intermediate portion of each of the support wires 12 is fixed to a projecting joint portion 16 integrally formed with the bobbin 4.

Next, the procedure for assembling the objective lens driving device shown in FIG. 1 will be described.

First, the following preparations are made individually.

The outer yoke 9 and the inner yoke 10 are integrally formed with the frame 11, and the outer yoke 9 is formed.
The permanent magnet 8 is attached to and bonded.

The supporting member 14 is screwed to the frame 11, and one end of each supporting wire 12 is soldered to the printed circuit board 13.

The objective lens 2 is adhered to the lens holder 1, the tracking coils 6 and the focusing coil 7 are wound around the bobbin 4, and the bobbin 4 is adhered to the lens holder 1.

After each preparation is performed as described above, next, the permanent magnet 8 and the outer yoke 9 are inserted into the space 3 of the lens holder 1 where the bobbin 4 is not arranged, and the bobbin 4 is inserted. The lens holder 1 to which the bobbin 4 is fixed is arranged so that the inner yoke 10 is inserted into the hole 5. After that, the unsoldered ends of the support wires 12 soldered to the printed circuit board 13 are inserted from outside the predetermined side surfaces of the frame 14, and then inserted into the corresponding holes 15 of the support member 14. Then, the printed circuit board 13 is screwed to a predetermined side surface of the frame 11 to stretch each support wire 12. here,
Since each support wire 12 is disposed adjacent to each joint portion 16 formed on the bobbin 4, the joint portion 16 corresponding to each support wire 12 in the middle portion.
The assembly is completed by fixing the lens holder 1 to the frame 11 by soldering and suspending the lens holder 1 so as to be displaceable.

When the objective lens driving device is completely assembled, the tracking coil 6 and the focusing coil 7 are orthogonally arranged in the magnetic gap between one magnetic pole surface of the permanent magnet 8 and the inner yoke 10 magnetized to the other magnetic pole. A part is inserted. Therefore, the lens holder 1 can be driven in the tracking direction and the focusing direction by supplying a control current to each of the tracking coil 6 and the focusing coil 7.

Next, the portion related to the bobbin 4 having the features of the present invention will be described in detail.

As shown in FIG. 2, the bobbin 4 is formed in a thin trapezoidal shape in plan view, and the winding portions 4a and 4b around which the tracking coils 6 of the bobbin 4 are wound consider the insertion portion of the inner yoke 10. Then, it is formed in an inverted C-shape with a slant.
The winding portions 4a and 4b are formed so that the cross-sectional area gradually increases toward the central portion of the bobbin 4.

Here, the bobbin 4 is constructed such that each tracking coil 6 and focusing coil 7 are sequentially wound by an automatic machine. In order, first, each tracking coil 6 is wound and then the focusing coil is wound. Is made to be wound.

When winding each tracking coil 6, the wires forming the tracking coil 6 are wound on the winding portions 4a and 4b.
In this winding, first, the wire is entangled with a predetermined coupling portion 16 of the bobbin 4, and then the winding portion 4a on one side is closely attached at a constant pitch from the outside with a small cross-sectional area. Winding around. When the winding of the wire of one winding portion 4a is completed, the winding of the other winding portion 4 is continued next.
Similarly, the wire is wound from the outside with a small cross-sectional area of b, and when the winding is completed, the wire is wound on another connecting portion 16 formed on the same surface as the connecting portion 16 on which the wire is entangled. The winding of each tracking coil 6 is completed by entwining and cutting the wire.

By the way, as described above, the wires constituting each tracking coil 6 are directed from the outside of the bobbin 4 having a small cross-sectional area of each winding portion 4a, 4b to the inside of the bobbin 4 having a large cross-sectional area. Winding is performed. For that reason,
Along with the winding operation of winding the wire, a force is generated in the wound wire toward the adjacent wire on the winding start end side.

Therefore, the wound wire has a function of closely adhering to the adjacent wire on the winding start end side, which can prevent the adjacent wires from being wound apart from each other, and at the same time, the wires can be wound together. It becomes easy to make it stick evenly and to wind.

Further, each tracking coil 6 is wound in an inverted V-shape in a slanted manner, and the effective portion of the tracking coil 6 is efficiently arranged in the permanent magnet 8, the inner yoke 10 and the magnetic gap. The sensitivity is being improved.

On the other hand, the wire forming the focusing coil 7 is provided on the back surface of the surface on which the coupling portions 16 used when winding the tracking coils 6 are formed in the state where the tracking coils 6 are wound. The coupling portions 16 formed in the same manner are used as the starting end and the terminating end, and are wound in the vertical direction so as to surround the entire side surface of the bobbin 4.

By the way, in order to suspend the lens holder 1 so that it can be displaced in a stable state, the lens holder 1 is supported by four supporting wires 12 at predetermined four points at equal intervals from the center. Further, in each of the coupling portions 16 formed on the bobbin 4, four portions, that is, the starting end and the terminating end of the tracking coil 6 and the starting end and the terminating end of the focusing coil 7 are integrally formed on the bobbin 4, and the respective coupling portions 16 are formed. The formed position is set according to the connecting portion of each support wire 12.

On the other hand, as described above, each coupling portion 16 includes
Tracking coil 6 or focusing coil 7
The wires that make up are entwined. Then, the entangled wire has a coating film for insulation peeled off by heating in order to relay the energization to each tracking coil 6 or focusing coil 7. Therefore, each support wire 12 can be soldered to the corresponding coupling portion 16, respectively, whereby the lens holder 1 to which the bobbin 4 is fixed can be soldered to the frame 1 by each support wire 12.
Can be hung on 1.

[0034]

As described above, according to the present invention, the drive coil is wound around the bobbin formed separately from the lens holder, and then the bobbin is fixed to the lens holder. Can be wound by an automatic machine, and the shape of the portion around which the drive coil of the bobbin is wound is devised, and the wire that constitutes the drive coil is wound from the smaller cross section toward the larger side. Since this is done, the wire can be wound evenly and closely, and the objective lens driving device with good workability and good quality can be provided.

Further, according to the present invention, each bobbin is provided with each connecting portion for connecting each supporting wire for suspending to the supporting frame, and the predetermined connecting portion is associated with the start end and the end of the wire constituting the drive coil. Since they are stopped, it is possible to simplify the process for connecting those wires to the support wires in order to energize the drive coil.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a developed plan view showing a main part of the present invention.

[Explanation of symbols]

 1 Lens Holder 4 Bobbins 4a, 4b Winding Part 6 Tracking Coil 7 Focusing Coil 8 Permanent Magnet 9 Outer Yoke 10 Inner Yoke 11 Frame 12 Support Wire 16 Coupling Part

Claims (2)

[Claims] 1. An objective lens driving device, wherein a driving coil is mounted on a lens holder to which an objective lens is fixed, and the objective lens is driven according to a driving signal supplied to the driving coil, which constitutes the driving coil. An objective lens driving device, wherein a bobbin around which the wire is wound is formed such that a cross-sectional area of the wire gradually increases from a winding start end side toward a winding end side. 2. An objective lens driving device comprising a lens holder to which an objective lens is fixedly mounted, and a bobbin to which a drive coil is attached. The objective lens driving device includes respective supports for suspending the lens holder displaceably on a support frame. An objective lens driving device characterized in that each bobbin is provided with a coupling part for coupling a wire, and a start end and an end of the wire forming the drive coil are respectively locked to predetermined coupling parts.