JPH0366035A - Support for optical pickup - Google Patents

Abstract

PURPOSE:To surely trace an light beam onto a track of an optical disk by providing a balancer balancing an inertia generated in an optical pickup when an acceleration is exerted on a frame of a support of the optical pickup and a force acting on the optical pickup. CONSTITUTION:A balancer 82 provided with a balance weight 81 is fitted freely turnably to a frame 62 around a shaft 83, the balancer 82 connects to an optical pickup 71 via the shaft 84, a link member 85 and a shaft 86 and the weight 81 and the optical pickup 71 are moved in the opposite direction. Moreover, when an acceleration is exerted on the frame 62, the weight 18 balances an inertia generated in the optical pickup 71 and the force exerted on the pickup 71 due to the inertia of the weight 81. When a focusing coil 76 is energized, a drum 73 is driven in the focusing direction by the interaction between the magnetic field generated in a coil 76 and the magnetic field by magnets 64, 64 fitted to the frame 62 to apply focusing control.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is provided in an optical information recording/reproducing device, etc., and is capable of moving an optical pickup to a desired track among a plurality of tracks formed on an optical recording medium. The present invention relates to a support device for an optical pickup that supports it movably so that it can be moved to a corresponding position.

[Conventional technology]

For example, in an optical information recording and reproducing apparatus that records and/or reproduces information on an optical disc that is a disc-shaped recording medium, an optical disc 11 is rotated and driven as shown in FIGS. 6 to 8. A disk drive motor 12 and a support device 21 for supporting an optical pickup 31 are provided.

The disk drive motor 12 is attached to a frame 22 that constitutes a support device 21 .

A turntable 13 on which the optical disc 11 is placed is attached to the rotating shaft 12a of the disc drive motor 12.

The frame 22 is also provided with two mutually parallel guide shafts 23, which support the optical pickup 31 so as to be movable in the radial direction of the optical disk, that is, in the tracking direction. The frame 22 further includes, along the guide shafts 23, 23,
Two magnets 24, 24 are provided.

The optical pickup 31 is provided with a drum 33 equipped with an objective lens 32 having an optical axis in a direction perpendicular to the recording surface of the optical disk 11, that is, in a focusing direction. The drum 33 is attached to the casing 35 via leaf springs 34 so that it can swing in the focusing direction.

A focusing coil 36 is wound around the drum 33, and by energizing the focusing coil 36, the magnets 24, 24 attached to the frame 22 are
The drum 33 is driven in the focusing direction by interaction with the magnetic field, and focusing control is performed.

Also, tracking coils 37 are wound around the drum 33 on both sides in the tracking direction, and by energizing the tracking coils 37, the magnet 2
Due to the interaction with the magnetic fields 4 and 24, the drum 33 is driven together with the casing 35 in the tracking direction, and tracking control is performed.

[Problem to be solved by the invention]

In an optical information recording/reproducing device or the like, it is necessary to cause a light beam generated by an optical pickup 31 to accurately follow a track formed on an optical disk 11. Therefore, tracking control is performed by driving the optical pickup 31 or the objective lens 32 in the radial direction of the optical disk 11 through the interaction between the magnets 24 and the tracking coils 37 and 37 as described above. It has become.

However, in the conventional optical pickup support device described above,
When acceleration is applied to the frame 22, the relative position between the frame 22 and the optical pickup 31 tends to change due to the inertial force generated by the optical pickup 31. Therefore, it is difficult to cause the light beam generated by the optical pickup 31 to reliably follow the tracks of the optical disk 11.

Therefore, there is a problem in that when vibration or external force is applied to an optical information recording/reproducing device or the like, normal recording and/or reproduction tends to fail.

Therefore, as shown in FIGS. 9 to 11, for example, a support shaft 41 is provided in a direction perpendicular to the recording surface of the optical disk 11.
A device in which an optical pickup 31 is rotatably provided on this support shaft 41 is also used.

That is, a drum 33 that includes an objective lens 32 and a focusing coil 36 and is swingably supported in the focusing direction via leaf springs 34 and an annular focusing magnet 43 is connected to one end of the casing 35 of the optical pickup 31. On the other hand, a weight 44 is provided on the other end side of the casing 35 to balance the magnet 43, drum 33, and the like.

In addition, tracking coils 37 and 37 are attached to the casing 35.
is provided, while tracking magnets 42 are provided on the frame 22, and this tracking coil 3
7, 37 and the magnetic fields of the tracking magnets 42, 42, the optical pickup 31 is rotated about the spindle 41, as shown in FIG.
The drum 33 can be driven between the inner circumferential side and the outer circumferential side of the optical disk 11.

With this configuration, even if acceleration is applied to the frame 22, the inertial force generated by the focusing magnet 43, drum 33, etc. is balanced with the inertial force generated by the weight 44, so that the optical pickup 31 does not rotate. Therefore, the tracking control will not become uncertain.

By the way, in order to detect with high precision the deviation between the track formed on the optical disk 11 and the light beam emitted by the optical pickup 31, that is, the tracking error, from the direction parallel to the track with respect to the irradiation position of the main beam, A three-spot method is often used in which sub-beams are irradiated at positions on both sides in slightly shifted directions.

However, in the optical pickup support device configured to perform tracking by rotating the optical pickup 31 as described above, the trajectory of the light beam due to tracking becomes an arc. Therefore, for example, as shown in Figure 13,
The angle between the tangent at the irradiation position of the main beam 14 on the track lla formed on the optical disk 11 and the line connecting the irradiation position of the two sub-beams 15, 15 is, for example, the track lla on the inner circumferential side. It is +α for the track llb on the outer circumferential side, while it is -β for the track llb on the outer circumferential side.

For this reason, this type of optical pickup support device requires
When acceleration is applied to frame 22, frame 22
Although it is possible to suppress changes in the relative position between the optical pickup 31 and the optical pickup 31, it is not possible to use the three-beam method, which is a highly accurate tracking error detection method.

[Means to solve the problem]

In order to solve the above-mentioned problem, an optical pickup support device according to claim 1 supports an optical pickup so as to be movable in a linear direction substantially perpendicular to a track formed on an optical recording medium. The support device is provided with a balancer that balances the inertia force generated by the optical pickup and the force acting on the optical pickup when acceleration is applied to the frame that constitutes the support device for the optical pickup. It is a feature.

In order to solve the above problem, an optical pickup support device according to claim 2 is the optical pickup support device according to claim 1, wherein the balancer is a flexible rocking device. The optical pickup and the balancer are provided to be swingable with respect to the frame via the support part, and the optical pickup and the balancer are connected via a link member having flexible swing support parts at both ends. It is characterized by

[For production]

With the above configuration, when acceleration is applied to the frame, the inertia force generated by the balancer balances the inertia force generated by the optical pickup and the force acting on the optical pickup, so that the relative position between the frame and the optical pickup can be adjusted. No changes occur. Therefore, the light beam generated by the optical pickup can be made to reliably follow the track of the optical disc.

Moreover, since the optical pickup is supported so as to move in a straight line substantially perpendicular to the tracks formed on the optical recording medium, regardless of the track irradiated with the light beam, two
Since the angle between the line connecting the irradiation positions of the two sub-beams and the track is always constant, the three-beam method, which is a highly accurate tracking error detection method, can be used.

〔Example〕

As an embodiment of the present invention, an example of an optical information recording and reproducing apparatus that records and/or reproduces information on an optical disk, which is a disk-shaped recording medium, will be explained with reference to FIGS. 1 to 3. Then, it is as follows.

For example, the optical information recording/reproducing device has the figures 1 to 3.
As shown in the figure, a disk drive motor 52 that rotationally drives an optical disk 51 and a support device 61 that supports an optical pickup 71 are provided.

The disk drive motor 52 is attached to a frame 62 that constitutes a support device 61.

A turntable 53 on which the optical disk 51 is placed is attached to the rotating shaft 52a of the disk drive motor 52.

The frame 62 is also provided with two mutually parallel guide shafts 63, which support the optical pickup 71 so as to be movable in the radial direction of the optical disk 51, that is, in the tracking direction. frame 62
Further, two magnets 64, 64 are provided along the guide shafts 63, 63.

The optical pickup 71 is provided with a drum 73 equipped with an objective lens 72 having an optical axis in a direction perpendicular to the recording surface of the optical disk 51, that is, in the focusing direction. This drum 73 is attached to a casing 75 via leaf springs 74 so that it can swing in the focusing direction.

A focusing coil 76 that generates a magnetic field in the focusing direction is wound around the drum 73, and a tracking coil 77 that generates a magnetic field in the tracking direction is wound around the drum 73.
- 77 is wound on both sides of the drum 73 in the tracking direction.

Further, a balancer 82 including a balance weight 81 is attached to the frame 62 so as to be rotatable about a shaft 83 . This balancer 82 is connected to the optical pickup 7 via a shaft 84, a link member 85, and a shaft 86.
1, so that the balance weight 81 of the balancer 82 and the optical pickup 71 move in opposite directions. Further, the balance weight 81 is configured to support the optical pickup 7 when acceleration is applied to the frame 62.
The inertia force generated by the balance weight 81 and the force acting on the optical pickup 71 due to the inertia force of the balance weight 81 and the like are set so as to be balanced.

In the above configuration, when the focusing coil 76 is energized, the magnetic field generated by the focusing coil 76 and the magnets 64 and 64 attached to the frame 62 are generated.
Due to the interaction with the magnetic field, the drum 73 is driven in the focusing direction, and focusing control is performed.

On the other hand, when the tracking coils 77 and 77 are energized,
Due to the interaction between the magnetic fields generated by the tracking coils 77 and the magnetic fields of the magnets 64, the drum 73 is driven in the tracking direction together with the casing 75, and tracking control is performed. That is, the light beam generated by the optical pickup 71 can be irradiated onto a desired track among the concentric tracks (not shown) formed on the optical disk 51.

At this time, the optical pickup 71
63 in the radial direction of the optical disk 51; Therefore, for example, if the optical pickup 71 irradiates one main beam and two sub-beams onto the optical disc 51, the tangent at the irradiation position of the main beam on the track of the optical disc 51 and the irradiation position of the two sub-beams. The angle with the line connecting is
All are the same on both tracks.

Therefore, as a method for detecting tracking errors with high precision, a three-spot method can be used in which sub-beams are irradiated on both sides of the main beam irradiation position in a direction slightly shifted from a direction parallel to the track. .

Further, for example, if acceleration in the tracking direction is applied to the frame 62, the optical pickup 71 generates an inertial force in the inner circumferential direction of the optical disk 51. That is, the optical pickup 71 is relative to the frame 62,
It attempts to move toward the inner circumference of the optical disk 51.

On the other hand, the balance weight 81 of the balancer 82 generates an inertial force in the inner circumferential direction of the optical disk 51, similarly to the optical pickup 71. However, this inertial force is applied to the optical pickup 7 via the shaft 84, the link member 85, and the shaft 86.
1 to move the optical pink-up 71 toward the outer circumference of the optical disk 51 relative to the frame 62.

The balance weight 81 is set so that the inertial force generated by the optical pickup 71 and the force acting on the optical pickup 71 are balanced. Therefore, the optical pickup 71 does not move in the tracking direction due to the acceleration applied to the frame 62.

Therefore, even if vibrations or external forces act on the optical information recording/reproducing device, tracking control can be performed reliably.

In this embodiment, an example in which the link mechanism is configured by the balancer 82, the shaft 83, the shaft 84, the link member 85, the shaft 86, and the casing 75 of the optical pickup 71 has been described, but the present invention is not limited to this. For example, the fourth
As shown in the figure, a frame fixing part 91 balancer part 92,
The link portion 93 and the casing fixing portion 94 are integrally formed, and the respective portions are connected via hinge portions 95, 96, and 97, which are flexible rocking support portions. It may be something that exists.

According to this, the number of parts required is small, so there is no increase in assembly man-hours or manufacturing costs, and an optical pickup support device that can perform reliable tracking control without being affected by vibration or external force. Can be configured.

Further, the positions where the balancer 82 and the balancer part 92 are provided are as follows.
As shown in FIG. 5, for example, the frame fixing portion 9
1 and the balancer section 92 may be provided on the outer circumferential side of the optical disk 51 relative to the optical pickup 71, may be provided on the inner circumferential side of the optical disk 51, or may be provided below the optical pickup 71. But that's fine. Furthermore, two or more balancers 82 may be provided to balance the moment generated when the optical pickup 71 moves.Furthermore, the position of the casing fixing part 94 may be adjusted as described above. The optical pickup 71 is not limited to being located on the side of the optical pickup 71, and may be located on the outer circumferential side of the optical disk 51 with respect to the optical pickup 71, or on the inner circumferential side of the optical disk 51.
It may be located below.

〔Effect of the invention〕

As described above, the optical pickup support device according to claim 1 is an optical pickup support device that supports the optical pickup so as to be movable in a linear direction substantially perpendicular to a track formed on an optical recording medium. The structure includes a balancer that balances the inertial force generated by the optical pickup and the force acting on the optical pickup when acceleration is applied to the frame constituting the support device for the optical pickup.

As a result, even if acceleration is applied to the frame, the inertial force generated by the optical pickup and the force acting on the optical pickup are balanced, so the relative position between the frame and the optical pickup does not change. , the light beam generated by the optical pickup can be made to reliably follow the track of the optical disk.

Therefore, even if vibrations or external forces act on the optical information recording/reproducing device or the like, accurate tracking control can be performed, resulting in the effect that normal recording and/or reproduction can be reliably performed.

Moreover, regardless of the track irradiated with the light beam, 2
Since the angle between the line connecting the irradiation positions of the two sub-beams and the track is always constant, the three-beam method, which is a highly accurate tracking error detection method, can be used.

As described above, the support device for an optical pickup according to claim 2 is the support device for an optical pickup according to claim 1, in which the balancer is supported through a swinging support portion having flexibility. is provided to be swingable with respect to the frame, and the optical pickup and balancer are connected via a link member having flexible swing support sections at both ends.

This has the effect that it is possible to configure an optical pickup support device that can perform reliable tracking control without being affected by vibration or external force without increasing assembly man-hours or manufacturing costs.

[Brief explanation of drawings]

1 to 3 show one embodiment of the present invention. FIG. 1 is a perspective view showing the structure of an optical pickup support device. FIG. 2 is a plan view of the same. FIG. 3 is a sectional view taken along the line CC in FIG. 2. FIG. 4 is a perspective view showing another embodiment. FIG. 5 is a perspective view showing still another embodiment. 6 to 13 show conventional examples. FIG. 6 is a perspective view showing the structure of a conventional optical pickup support device. FIG. 7 is a plan view of the same. FIG. 8 is a sectional view taken along the line A-A in FIG. 7. FIG. 9 is a perspective view showing the structure of another conventional optical pickup support device. FIG. 10 is a plan view of the same. FIG. 11 is a sectional view taken along the line BB in FIG. 10. FIG. 12 is an explanatory diagram showing the tracking operation of a conventional optical pickup. FIG. 13 is an explanatory diagram showing a tracking operation when a three-spot method is used in a conventional optical pickup. 51 is an optical disk (optical recording medium), 71 is an optical pickup, 61 is a support device, 62 is a frame, 82 is a balancer, 93 is a link portion, and 96 and 97 are hinge portions (swing support portions).

Claims (1)

[Scope of Claims] 1. An optical pickup support device that supports an optical pickup so as to be movable in a straight line substantially perpendicular to tracks formed on an optical recording medium, the frame constituting the optical pickup support device. 1. A support device for an optical pickup, comprising a balancer that balances an inertial force generated by the optical pickup and a force acting on the optical pickup when acceleration is applied to the optical pickup. 2. The balancer is provided to be swingable with respect to the frame via a flexible swinging support part, and the optical pickup and the balancer are connected to the flexible swinging support part at both ends. 2. The optical pickup support device according to claim 1, wherein the optical pickup support device is connected via a link member having a link member.