JPH0991722A - Optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical pickup device which is simple in constitution and improved in coil efficiency. SOLUTION: A focus electromagnetic coil 13 whose coil axis is perpendicular to the focus direction is arranged in opposition with a first yoke 12. On this coil 13, a pair of two tracking electromagnetic coils 14a, 14b are arranged with a specified interval and permanent magnets 15 whose S-pole and N-pole are selectively inplane magnetized are arranged in opposition with these focuss electromagnetic coil and tracking electromagnetic coils 14a, 14b. By this, driving forces in the focus direction and tracking direction are selectively generated in cooperation with these first yoke 12, the S-pole and the permanent magnet 15, and the second yoke 16 to move and control a mobile holder 10 in the focus direction and the tracking direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup device used for recording / reproducing information on / from an optical information recording medium such as an optical disc or an optical card.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 2, an optical pickup device of this type focuses a movable holder 2 called an actuator provided with an objective lens 1 for entering and leaving light through a pair of leaf spring mechanisms 3 and 3. Direction, that is, the direction orthogonal to the recording surface of the information recording medium (the direction approaching or leaving the recording surface) and the tracking direction, that is, the direction parallel to the recording surface of the information recording medium and intersecting the track (recording It is arranged so as to be rotatable in a direction intersecting the rotation direction of the medium). The base ends of the leaf spring mechanisms 3 and 3 are supported by a support body (not shown).

In the movable holder 2, a pair of focus electromagnetic coils 4 constituting a drive mechanism with the objective lens 1 sandwiched therebetween are disposed so as to face each other with their winding axis directions substantially parallel to the focus direction (see FIG. 3). ). For example, first yokes 5 and 5 provided on the support (not shown) are loosely inserted in the focus electromagnetic coils 4 and 4, respectively.

Further, on the focus electromagnetic coils 4 and 4,
A set of two tracking electromagnetic coils 6a, 6b, 6a,
6b are arranged so as to be stacked with a predetermined interval in the tracking direction. These focus electromagnetic coils 5, 5 and tracking electromagnetic coils 6a, 6b, 6a,
6b is sandwiched by a pair of permanent magnets 7,7. The pair of permanent magnets 7, 7 are attached to the pair of second yokes 8, 8 provided on the support (not shown).

As a result, the focus electromagnetic coils 4, 4
And tracking electromagnetic coils 6a, 6b, 6a, 6b
When the current is supplied in the i direction, the permanent magnets 7, 7 and
The driving forces F and T are selectively generated in the focus direction and the tracking direction by the action of the magnetic field B generated by the first and second yokes 5, 5, 8 and 8 in cooperation with each other. Then, the movable holder 2 is controlled to move in the focus direction and the tracking direction via the leaf spring mechanisms 3 and 3 by the driving forces F and T, and the objective lens 1 thereof is located at the signal recording position of the optical information recording medium (not shown). Positioning is controlled.

It should be noted that the objective lens 1 of the movable holder 2 is optically coupled with a light emitting / receiving portion (not shown) via respective optical paths. A laser beam from a light emitting / receiving unit (not shown) is guided to the objective lens 1 through an optical path and irradiates the laser beam on an optical information recording medium (not shown). Then, the reflected light reflected by the optical information recording medium (not shown) is incident on the objective lens 1 again and guided to the light emitting / light receiving unit (not shown).

However, in the above optical pickup device, due to the arrangement configuration of the focus electromagnetic coils 4 and 4, the driving force cooperates with the permanent magnets 7 and the first and second yokes 5, 5 and 8, 8. The effective portion of the focus electromagnetic coils 4 and 4 used to generate the current is interposed between the first yokes 5 and 5 and the second yokes 8 and 8 on one side (indicated by hatching in FIG. 2). Since there are only a few parts (shown), the coil efficiency is poor and there is a problem that the structure becomes large when configured to generate a large driving force.

Therefore, as shown in FIG. 4, a pair of focus electromagnetic coils 4 and 4 are sandwiched by a pair of first yokes 5 and 5 provided on the support (not shown), and the winding axial direction thereof is set. They are arranged so as to be substantially orthogonal to the focus direction (see FIG. 5). The pair of focus electromagnetic coils 4 and 4 are composed of two tracking electromagnetic coils 6a,
It is sandwiched by 6b, 6a and 6b. The pair of tracking electromagnetic coils 6a, 6b and 6a, 6b are mounted on the focusing electromagnetic coils 4, 4 with a predetermined distance in the tracking direction. The focus electromagnetic coils 4 and 4 and the tracking electromagnetic coils 6a,
6b, 6a and 6b are arranged so as to be sandwiched via a pair of second yokes 8 and 8 provided on the support (not shown). The second yokes 8 and 8 are provided with first permanent magnets 9a and 9a, which are in-plane magnetized with S poles and N poles, facing the focus electromagnetic coils 4 and 4, respectively. , 6b, 6a, 6b, the second permanent magnets 9b, 9b and 9c having N poles magnetized,
9c is mounted and arranged.

In the above structure, the focus electromagnetic coil 4 and the tracking electromagnetic coils 6a, 6b and 6a, 6b are used.
When the current is supplied in the i direction, the first and second permanent magnets 9a, 9a, 9b, 9b, 9c, 9c cooperate with the first and second yokes 5, 5 and 8, 8. The driving force F and T are selectively generated in the focus direction and the tracking direction by the action of the magnetic field B generated by the action. Then, the movable holder 2 has the leaf spring mechanisms 3 and 3 (in FIG. 4,
For convenience of illustration, the movement is controlled in the focus direction and the tracking direction via the omission (see FIG. 2), and the objective lens 1 is positionally controlled at the signal recording position of the optical information recording medium.

However, in the above-mentioned optical pickup device, the focus electromagnetic coil 4, which is used for generating the driving force, is used.
The effective portion of 4 can be widely taken as both side portions (see FIG. 5) sandwiching the winding axis of the focus electromagnetic coils 4, 4 sandwiched between the first yokes 5, 5 and the second yokes 8, 8. Although it becomes possible and the coil efficiency can be improved, as the permanent magnet, the first and second permanent magnets 9a, 9a, 9 are used.
There is a problem in that the configuration becomes complicated because a plurality of such elements as b, 9b, 9c and 9c are required.

[0011]

As described above, the conventional optical pickup device has a problem that the coil efficiency is poor, the number of parts is large, and the structure is complicated. The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical pickup device having a simple configuration and capable of realizing highly efficient coil efficiency.

[0012]

SUMMARY OF THE INVENTION According to the present invention, an optical pickup main body for irradiating laser light onto a signal recording surface of an optical information recording medium to record or reproduce information on the optical recording medium is provided on the signal recording surface. In an optical pickup device that is arranged so as to be movable in a tracking direction that is parallel to, and intersects with a track and a focus direction that is orthogonal to the signal recording surface, with an optical inlet / outlet of the optical pickup body sandwiched therebetween. A pair of first yokes that face each other, and a pair of first yokes that face each other with the pair of first yokes sandwiched therebetween;
A pair of first electromagnetic coils configured such that the winding axis direction is substantially orthogonal to the focus direction and the winding direction is the tracking direction, and the pair of first electromagnetic coils are arranged to face each other with the pair of first electromagnetic coils interposed therebetween. A pair of second electromagnetic coils each of which has the same winding axis direction as the first electromagnetic coil and is arranged at a predetermined interval in the winding direction of the first electromagnetic coil; The pair of first electromagnetic coils and the pair of second electromagnetic coils are arranged so as to face each other,
The S and N poles that cooperate with the first and second electromagnetic coils to generate a driving force in the focus direction and the tracking direction and control movement of the optical pickup body in the focus direction and the tracking direction are the first and second magnetic poles. A pair of permanent magnets that are selectively magnetized in-plane facing the first and second electromagnetic coils, and a pair of second yokes that are arranged to face each other with the pair of permanent magnets sandwiched therebetween are configured. It is a thing.

According to the above construction, when the electric current is supplied to the first and second electromagnetic coils in the optical pickup body,
The driving force in the focus direction and the tracking direction is applied by the action of the first yoke, the permanent magnets in which the S pole and the N pole are in-plane magnetized, and the second yoke, so that the light entrance / exit can be detected by the optical information. The movement is controlled in the focus direction and the tracking direction so as to face the signal recording surface of the recording medium. Thus, with a simple structure including only one permanent magnet, the coil effective portion of the first electromagnetic coil sandwiches the winding axis of the first electromagnetic coil sandwiched between the first yoke and the permanent magnet. It becomes both sides, and it becomes possible to obtain a large driving force.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an optical pickup device according to an embodiment of the present invention, in which a movable holder 10 that constitutes an optical pickup body.
An objective lens 11 that constitutes a light entrance / exit is provided in the. The objective lens 11 has a light-emitting / light-receiving section (not shown) optically coupled therein through an optical path, and is positioned and controlled so as to face a signal recording surface of an optical information recording medium (not shown).

The movable holder 10 is provided with a pair of first yokes 12, 12 with the objective lens 11 interposed therebetween. The first yokes 12, 12 have a pair of focus electromagnetic coils 13, 13. Are arranged so as to face each other with their winding axis directions substantially orthogonal to the focusing direction (see FIG. 5). This pair of focus electromagnetic coils 13,
A set of two tracking electromagnetic coils 14a, 14b, 14a, 14b are mounted on 13 so as to be stacked with a predetermined space in the tracking direction (winding direction of the focus electromagnetic coil). The pair of focus electromagnetic coils 13, 13 and the tracking electromagnetic coils 14a, 14b, 14a, 14b are the permanent magnets 1
5, 15 are opposed to each other and sandwiched by the permanent magnets 15, 15. The permanent magnets 15 and 15 are attached to the second yokes 16 and 16 provided on the support (not shown) so as to face the focus electromagnetic coils 13 and 13 and the tracking electromagnetic coils 14a, 14b, 14a and 14b. The S pole and the N pole are arranged in the plane of the focus electromagnetic coils 13 and 13 and the focus electromagnetic coils 14a and 14a.
It is magnetized so as to face b, 14a and 14b. That is, the permanent magnets 15 and 15 have focus electromagnetic coils 13 and 13 respectively.
The in-plane magnetization is applied to the S pole and the N pole, and the in-plane magnetization is applied to the N pole corresponding to the tracking electromagnetic coils 14a, 14b, 14a, 14b.

Although not shown, the movable holder 10 is movably supported in the focus direction and the tracking direction by a support through a leaf spring mechanism similar to that shown in FIG.

In the above structure, the focus electromagnetic coils 13, 13 and the tracking electromagnetic coils 14a, 14
b, 14a, 14b, when current is supplied in the i direction,
By the action of the first yokes 12 and 12, the S poles and N poles in-plane magnetized by the permanent magnets 15 and 15, and the magnetic field B generated in cooperation with the second yokes 16 and 16, The driving forces F and T are selectively generated in the focus direction and the tracking direction. At this time, the focus electromagnetic coils 14, 14
Is the first yoke 12, 12 and the permanent magnets 15, 15
Both side portions of the winding shaft sandwiched by are coil effective portions (see FIG. 5), and a driving force F corresponding to the effective portions is generated.

Here, the movable holder 10 is controlled to move in the focus direction and the tracking direction via a leaf spring mechanism (not shown) by these driving forces F and T, and the objective lens 11 thereof has the above optical information recording. Medium (not shown)
Positioning is controlled to the signal recording position of.

Here, the movable holder 10 has the above-mentioned light emission /
The light emitted from the light receiving portion (not shown) is accurately applied to the signal recording surface of the optical information recording medium (not shown) via the objective lens 11, and the reflected light is again returned to the objective lens. It is led to the above-mentioned light emitting / light receiving portion (not shown) through the path to record or reproduce a signal.

As described above, in the optical pickup device, the focus electromagnetic coil 1 faces the first yokes 12 and 12 with the winding axis direction substantially orthogonal to the focus direction.
3, 13 are provided, and the focus electromagnetic coils 13, 1 are arranged.
2 sets of tracking electromagnetic coils 14a, 14
b, 14a, 14b are arranged at a predetermined interval, and the S pole and the N pole are selectively in-plane magnetized so as to face the focus electromagnetic coils 13 and 13 and the tracking electromagnetic coils 14a, 14b, 14a, 14b. By arranging the permanent magnets 15 and 15 formed through the second yokes 16 and 16 to supply current to the focus electromagnetic coils 13 and 13 and the tracking electromagnetic coils 14a, 14b, 14a, and 14b, the first yoke The driving force in the focus direction and the tracking direction is selectively applied to the movable holder 10 by the action of the permanent magnets 15 and 15 in which the S and N poles are in-plane magnetized and the second yokes 16 and 16. It is configured to be applied and movement-controlled in the focus direction and the tracking direction.

According to this, the focus electromagnetic coil 1
3, 13 and tracking electromagnetic coils 14a, 14b,
In-plane magnetized permanent magnets 15 facing 14a, 14b,
With a simple configuration in which only 15 are arranged, the effective coil portions of the focus electromagnetic coils 13 and 13 have the first yoke 1
2 and 12 and the permanent magnets 15 and 15 sandwich both sides of the winding axis to achieve high-efficiency coil efficiency, and simplification of the configuration is ensured, and high coil efficiency can be achieved. .

In the above embodiment, the permanent magnet 1
Tracking electromagnetic coils 1 and 5 have in-plane magnetized S poles and N poles corresponding to focus electromagnetic coils 13 and 13.
Although it has been described that the N pole is in-plane magnetized so as to face 4a, 14b, 14a, 14b, the present invention is not limited to this magnetized structure and can be configured.

Further, in the above embodiment, the movable holder 10 is arranged on the support (not shown) through the leaf spring mechanism (not shown) so as to be movable and controllable in the focus direction and the tracking direction. However, the present invention is not limited to this support structure and can be applied. Therefore, it is needless to say that the present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the present invention.

[0024]

As described in detail above, according to the present invention, it is possible to provide an optical pickup device having a simple structure and capable of realizing highly efficient coil efficiency.

[Brief description of drawings]

FIG. 1 is a diagram showing an optical pickup device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a conventional optical pickup device.

FIG. 3 is a diagram showing an arrangement state of a focus electromagnetic coil and a tracking electromagnetic coil of FIG.

FIG. 4 is a diagram showing a conventional optical pickup device.

5 is a diagram showing an arrangement state of a focus electromagnetic coil and a tracking electromagnetic coil of FIG.

[Explanation of symbols]

 10 ... Movable holder. 11 ... Objective lens. 12 ... the first yoke. 13 ... Focus electromagnetic coil. 14a, 14b ... Tracking electromagnetic coils. 15 ... permanent magnet. 16 ... Second yoke portion.

Claims (2)

[Claims] 1. An optical pickup body for irradiating a signal recording surface of an optical information recording medium with laser light to record or reproduce information on the optical recording medium is parallel to the signal recording surface and is a track. In an optical pickup device arranged so as to be movable in a tracking direction intersecting with and a focus direction orthogonal to the signal recording surface, a pair of first first and second optical pickup devices are opposed to each other with a light inlet / outlet of the optical pickup main body interposed therebetween. Of the first yoke and the pair of first yokes, the winding axis direction is substantially orthogonal to the focus direction, and the winding direction is the tracking direction.
Of the first electromagnetic coil and the electromagnetic coil of the first electromagnetic coil and the first electromagnetic coil having the same winding axis direction as the first electromagnetic coil and having a predetermined interval in the winding direction of the first electromagnetic coil. And a pair of second electromagnetic coils composed of two electromagnetic coils, and the first and second electromagnetic coils are arranged so as to face each other with the pair of first electromagnetic coil and the second electromagnetic coil sandwiched therebetween. An S pole and an N pole that cooperate with an electromagnetic coil to generate a driving force in the focus direction and the tracking direction to control movement of the optical pickup body in the focus direction and the tracking direction.
A pair of permanent magnets whose poles face the first and second electromagnetic coils and are selectively in-plane magnetized, and a pair of second permanent magnets which are arranged to face each other with the pair of permanent magnets sandwiched therebetween.
And an optical pickup device. 2. The permanent magnet is in-plane magnetized such that the S pole and the N pole are arranged to face the first electromagnetic coil, and the N pole faces the second electromagnetic coil. The optical pickup device according to claim 1.