JPH01302544A - Actuator driving device - Google Patents

Abstract

PURPOSE:To improve driving sensitivity while the intensity of a movable part main body is maintained by providing a projecting part in one part on the side surface of the movable part main body or fixing a coil for driving to one part on the side surface of the projection-shaped movable part main body. CONSTITUTION:When a prescribed current flows to driving coils 5a and 5b which are fixed to projecting parts 9a and 9b of an actuator driving device, a movable part main body 2 is driven in a track direction by reaction with permanent magnets 6a and 6b for driving. At such a time, since a distance between a supporting shaft 1 and the coils 5a and 5b for driving is enlarged with providing the projecting parts 9a and 9b, driving torque to be generated in the coils 5a and 5b for driving is increased. Thus, the driving sensitivity can be improved while the intensity of the movable part main body is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an actuator drive device for driving a main body of a movable part of, for example, an optical pickup device, and particularly to improvement of the drive sensitivity thereof.

(Prior Art) Fig. 4 and Fig. 5 are a plan view and a front view showing a conventional actuator drive device, in which (1) is a support shaft;
(2) is a cylindrical movable body centered on the support shaft (1), (3) is an objective lens that collects the light fixed on the movable body (2), and (4) is the movable body Bearings that receive the support shaft (1) that is the center of rotation of (2), (5a) (5b
) is a driving coil that drives the movable part main body (2) in the track direction around the support shaft (1), and (6a) and (6b) are driving coils (5a) and (5b) arranged in a magnetic field. Driving permanent magnets (7a) (7b) are yokes that fix driving permanent magnets (6a) (6b), (8)
) is a base to which the support shaft (1) and yokes (7a) (7b) are fixed.

A conventional actuator drive device is configured as described above, and includes, for example, a driving permanent magnet (6a) that emits a magnetic field.
(6b)
) When a predetermined current is passed through (5b), a magnetic field is generated in the coil, and the repulsive force of the mutual magnetic force causes the movable part main body (2) to move around the support shaft (
1) is driven in the track direction around the center.

In other words, by changing the current value of the current flowing through the drive coils (5a) (5b), the amount of drive of the movable part main body (2) is changed, and thereby the light collected by the objective lens (3) is Positioning is performed at a specific position on the optical recording medium.

FIG. 6 shows a conventional example in which the movable part main body (2) has a shape protruding in one direction, and the drive coil (5a)
(5b) is fixed at a position near the center of the movable part main body (2). This example also operates in the same way as the conventional example shown in FIG.

(Problems to be Solved by the Invention) In the conventional actuator drive device as described above, in order to improve the seismic performance of the optical pickup, it is necessary to further improve the drive sensitivity.

Furthermore, in optical pickups intended for portable use, it is necessary to reduce power consumption, and for this purpose, it is also necessary to improve drive sensitivity.

In order to improve this drive sensitivity, a permanent magnet for drive (
6a) Strengthening the magnetic force of (6b) or moving part body (
2) weight reduction was considered, but the permanent magnet for the drive (
Strengthening the magnetic force in 6a) and (6b) increases the cost, and reducing the weight of the main body of the movable part poses problems in terms of strength.
There were problems such as the need for major modifications.

This invention was made to solve these problems, and aims to provide an actuator drive device that maintains the strength of the movable part body and improves drive sensitivity without requiring a significant increase in cost. purpose.

(Means for Solving the Problems) The actuator drive device according to the present invention is provided with a protrusion on a part of the side surface of the movable part main body, or a part of the movable part main body that is protruded in one direction. A driving coil is fixed and placed facing a driving permanent magnet with a predetermined gap therebetween.

(Function) In this invention, the distance between the support shaft and the drive coil,
Since the drive torque obtained by multiplying the drive torque by the electromagnetic force generated in the drive coil is made relatively large in relation to the weight 2 of the movable body, drive sensitivity is improved.

(Example) FIG. 1 is a diagram showing an example of the present invention, (1) to
(8) is exactly the same as the conventional device described above. (9a
) (9b) is a protrusion provided to improve drive sensitivity, made of the same material as the movable part main body (2), and is a part integrated with the movable part main body (2).

In the actuator drive device configured as described above, the drive coil (5a) (
When a predetermined current is passed through 5b), a magnetic field is generated, and the movable part main body (2) is driven in the track direction by the repulsive force between this magnetic field and the magnetic field from the driving permanent magnets (6a) and (6b). At this time, the support shaft (1) and the drive coils (5a) (5b
) by providing the protrusions (9a, 9b), the driving torque generated in the driving coils (5a, 5b) becomes large, and the sensitivity is improved.

In other words, in order to adjust the position of the objective lens (3) of the movable part main body (2) and position the light collected therefrom at a specific position on the optical recording medium, the driving coil (5a) (
By changing the current value of the current flowing through the drive coils (5b), the strength of the magnetic field generated in the drive coils (5a) (5b) is changed, thereby adjusting the repulsive force with the drive permanent magnets (6a) (6b). to adjust the amount of rotation of the movable part main body (2).

In addition, in the above embodiment, the movable part main body (2) has a cylindrical shape,
Although an example has been illustrated in which the protrusions (9a) and (9b) are provided on the movable part main body (2) and integrated with the movable part main body (2) to improve drive sensitivity, the present invention is not limited thereto. Instead, it may have other similar functions. Fig. 3 shows driving coils (5a) (5b) fixed to a part of the side surface of a movable part main body (2) having a shape protruding in one direction, and driving permanent magnets (6a) (6b) and predetermined positions. They are arranged facing each other with a gap in between, and the distance between the support shaft (1) and the drive coils (5a) and (5b) is larger than that of the conventional one shown in FIG. It has the same effect as.

Furthermore, in the embodiment shown in FIG. 1, a case has been described in which protrusions (9a) (9b) are added to a part of the side surface of the movable part main body (2), but the conventional movable part body (2) shown in FIG. Part body (
2) Excluding the part where the drive coils (5a) and (5b) are located, the side surface of the other movable part main body (2) is shaved as shown by the broken line to create a movable part having the same shape as the embodiment shown in FIG. When used as a main body, the driving sensitivity can be improved as the weight of the movable part is reduced, and similar effects can be achieved.

(Effects of the Invention) As described above, according to the present invention, by increasing the distance between the supporting shaft of the movable part main body and the driving coil, or by modifying the shape to some extent to reduce the weight, The drive sensitivity is improved while maintaining the strength of the movable body, and the modification cost is low.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing one embodiment of the present invention, Fig. 2 is a front view of Fig. 1, Fig. 3 is a plan view showing another embodiment of the invention, and Fig. 4 is a conventional actuator drive. FIG. 5 is a plan view showing the device, FIG. 5 is a front view of FIG. 4, and FIG. 6 is a plan view showing another conventional actuator drive device. In the figure, (1) is the support shaft, (2) is the main body of the movable part, and (3) is the main shaft.
) is the objective lens, (4) is the bearing, (5a) (5b) is the driving coil, (6a) (6b) is the driving permanent magnet,
(9a) and (9b) are protrusions of the main body of the movable part. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent: Patent Attorney Souji Sasaki Figure 1 Figure 2 Figure 3 Figure 6

Claims (1)

[Scope of Claims] A movable part body having a support shaft, a bearing with the support shaft as the center of rotation, a driving coil fixed to the side surface of the movable part main body, and a driving coil connected to the driving coil through a predetermined gap. In an actuator drive device having a driving permanent magnet disposed facing each other, a protrusion protrudes outward from a part of the side surface of the movable part main body, or a protrusion part of the movable part main body that protrudes in one direction. An actuator drive device characterized by having a drive coil fixed to a part of the side surface.