KR19990048541A - Drive of optical pickup - Google Patents

Abstract

The present invention reduces the distance between the permanent magnets in the focus direction by replacing the movable coil in the track direction by using a solenoid, thereby increasing the magnetic flux density to improve sensitivity, and accurately matching the force points in the focus direction and the track direction. The present invention relates to a driving device of an optical pickup in which the frequency of occurrence is reduced and thus the frequency of the secondary resonance mode is increased. In particular, it is installed at each end of the wire spring protruding from one side of the fixing member and converges a beam at the end. A driving member having an objective lens directed toward the side; A focusing coil installed inside the driving member in a state wound around an outer circumferential surface of the bobbin; A yoke which protrudes into the driving member so as to be disposed at both sides of one side of the focusing coil, and has a permanent magnet such that the driving member flows in the focusing direction by an electromagnetic force when a current is applied to the focusing coil; A pair of track coils provided on both outer sides of the driving member in a direction orthogonal to the yoke; And a pair of permanent magnets provided on both sides of the outer circumferential surface of the driving member so as to be in line with the track coil so that when the current is applied to the track coil, the driving member flows in the track direction by electromagnetic force. have.

Description

Drive of optical pickup

The present invention relates to a drive device for optical pickup, and more particularly, by matching the force point in the focusing direction with the force point in the track direction, and reducing the distance between the focusing coil and the permanent magnet, the optical resonance is reduced and the sensitivity is improved. A pickup drive device.

With the emergence of notebook PCs, CD-ROMs, and DVDs, optical pickup drives are becoming thinner, smaller, and lighter as the demand for higher speed increases. To make the optical pickup thin, an asymmetrical structure is used. FIG. 1 is a cross-sectional view of an asymmetric optical pickup driving apparatus, which includes a driving member 1 having an objective lens 2 that converges a beam and sends it toward a disk. The driving member 1 is wound around the focusing coil 3 and the track coil 4 so as to finely move the objective lens 2 in the focusing direction, that is, the vertical direction and the track direction, that is, the left and right directions, and these coils 3, 4 In the periphery), the permanent magnet 6 and the yoke 5 which generate electromagnetic force are provided. In addition, the driving member 1 is supported in an elastically suspended state to the fixing member 7 constituting the optical pickup. That is, it is supported by the conductive wire springs 8 fitted in all directions of the fixing member 7, and when power is applied to each coil 3 and 4 through each wire spring 8, the actuator 1 is driven by electromagnetic force. Is moved in the focusing or track direction and the information formed on the surface of the disc is reproduced.

In the conventional optical pickup configured as described above, when a current is applied to each of the coils 3 and 4, an electromagnetic force is generated by the magnetic field of the permanent magnet 6 formed in the yoke 5, and the fixing member 7 moves in the track direction or the focusing direction. When the beam emitted from the light source is scanned toward the objective lens 2 along the scanning path, the objective lens 2 converges the beam and scans the surface of the disk. In this process, the information of the disk is reproduced.

However, in the conventional optical pickup, since the force points of the focusing coil 3 and the track coil 4 are inconsistent apart by the interval g, the incidence of sub resonances increases, and the driving member having the same focusing coil 3 and the track coil 4 is the same. Due to the winding in (1), the distance between the permanent magnet and the magnetic flux is reduced. In addition, there are drawbacks such as the choice of good materials or a lot of effort in structural design to increase the secondary resonance point.

The present invention was developed in view of the conventional problem, and an object of the present invention is to replace the movable coil in the track direction by using a solenoid, thereby narrowing the distance between permanent magnets in the focus direction, thereby increasing the magnetic flux density to improve sensitivity. In addition, the force point of the focus direction and the track direction is exactly matched to reduce the incidence of the sub-resonance to provide an optical pickup driving device that the frequency of the flexible mode, that is, the secondary resonance mode is increased.

1 is a cross-sectional view of a conventional driving device;

2 is an exploded perspective view of the driving device of the present invention;

3 is a cross-sectional view of the drive device of the present invention.

<Description of the symbols for the main parts of the drawings>

10: driving member 11: objective lens

12 bobbin 13 focusing coil

14: York 15: permanent magnet

16: permanent magnet 17: track coil

18: support 19: holding member

20: wire spring 22: substrate

In order to achieve the above object, the present invention includes a driving member provided hanging on each end of the wire spring protruding from one side of the fixing member and having an objective lens for converging the beam to the front end; A focusing coil installed inside the driving member in a state wound around an outer circumferential surface of the bobbin; A yoke which protrudes into the driving member so as to be disposed at both sides of one side of the focusing coil, and has a permanent magnet such that the driving member flows in the focusing direction by an electromagnetic force when a current is applied to the focusing coil; A pair of track coils provided on both outer sides of the driving member in a direction orthogonal to the yoke; And a pair of permanent magnets provided on both sides of the outer circumferential surface of the driving member so as to be in line with the track coil so that when the current is applied to the track coil, the driving member flows in the track direction by electromagnetic force. have.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is an exploded perspective view of the drive device of the present invention and Figure 3 is a cross-sectional view of the drive device of the present invention. The driving member 10 is provided with the objective lens 11 coupled to the distal end by converging the beam to the disc. In the driving member 10, the bobbin 12 wound around the focusing coil 13 is coupled to the inside of the driving member 10 in order to finely move the objective lens 11 in the focusing direction, that is, the vertical direction. At this time, the bobbin 12 is composed of a hollow rectangular parallelepiped and the focusing coil 13 is wound around the outer circumferential surface of the bobbin 12. In addition, the bobbin 12 is located behind the driving member 10, that is, opposite the objective lens 11.

In addition, the yoke 14 and the permanent magnet 15 generating magnetic flux in the focusing coil 13 are installed in the driving member 10. The yoke 14 is disposed on both sides of one side of the focusing coil 13 and the permanent magnet 15 is provided on both sides of the focusing coil 14 so as to correspond to each other. In addition, the permanent magnet 16 is built in both sides of the outer peripheral surface of the drive member (10). Permanent magnets 16 are inserted into the grooves 10a formed on both sides of the outer circumferential surface of the drive member 10, and the track coils 17 corresponding to these permanent magnets 16 are supported by the support member 18 by the support member 18. 10) are provided on both sides. The support 18 is placed in a fixed state on the upper surface of the substrate 22 and the permanent magnet 16 of the track coil 17 is placed in a direction perpendicular to the permanent magnet 15 of the focusing coil 13. The strength points of the track coil 17 and the focusing coil 13 coincide with each other.

The fixing member 19 is installed on the upper surface of the substrate 22 to surround a part of the objective lens 11. The fixing member 19 allows the driving member 10 to flow, and wire springs 20 formed on the upper and lower sides of the driving member 10 are connected to the fixing member 19. The flexible material 21, which serves as a damper, is embedded in a portion where the wire spring 20 is connected.

In the present invention configured as described above, the fixing member 19 and the support 18 disposed on both sides thereof are respectively placed on the substrate 22. In addition, the fixing member 19 is installed to the driving member 10 is suspended on the front end of the wire spring 20 formed on the upper and lower sides, respectively. In this case, the focusing coil 13 wound around the bobbin 12 is provided inside the driving member 10, and permanent magnets 16 are formed on both sides of the outer circumferential surface of the driving member 10. Each permanent magnet 16 is provided to correspond to the track coil 17 formed on the support 18, the substrate 22 is provided with a yoke 14 protruding into the drive member 10 and the yoke 14 ) Is provided with a permanent magnet (15).

When power is applied to the focusing coil 13, electromagnetic force is generated by the magnetic flux generated between the yoke 14 and the permanent magnet 15, and the driving member 10 is finely flowed in the focusing direction. In addition, since the driving member 10 is connected to the flexible member 21 in a state in which the driving member 10 is suspended from the wire spring 20, vibration is reduced. In addition, when power is applied to the track coil 17 of the support 18, an electromagnetic force is generated between the permanent magnet 16 and the drive member 10 flows in the track direction. Therefore, the beam scanned via the objective lens 11 focuses precisely on the disk.

Also, the yoke 14 and the permanent magnet 15 for operating the focusing coil 13 are separated from the permanent magnet 16 for operating the track coil 17, and the focusing coil 13 and the track coil 17 are separated. The centers of force in both directions coincide. In addition, the center of gravity and the support point coincide in one place, thereby ensuring the robustness against the negative resonance which may be caused by the assembly tolerance. In addition, since it contains permanent magnets, it is structurally stable and the secondary resonance point can be brought high, thereby increasing the frequency of the secondary resonance mode.

According to the present invention configured as described above, by using the solenoid type permanent magnet and the track coil to control the flow in the track direction of the drive member, the resonance points of the track direction and the focusing direction are coincident with each other, thereby reducing negative resonance. In addition, since the distance between the focusing coil and the yoke and the permanent magnet can be reduced, the sensitivity is improved.

Claims (4)

A driving member installed on each end of the wire spring protruding from one side of the fixing member and provided with an objective lens for converging the beam to the disc and sending it toward the disc; A focusing coil installed inside the driving member in a state wound around an outer circumferential surface of the bobbin; A yoke which protrudes into the driving member so as to be disposed at both sides of one side of the focusing coil, and has a permanent magnet such that the driving member flows in the focusing direction by an electromagnetic force when a current is applied to the focusing coil; A pair of track coils provided on both outer sides of the driving member in a direction orthogonal to the yoke; And An optical pickup having a pair of permanent magnets installed on both sides of the outer circumferential surface of the driving member so as to be in line with the track coil, and having the pair of permanent magnets flowing in the track direction by an electromagnetic force when a current is applied to the track coil. Drive system. 2. The driving apparatus of claim 1, wherein the force center points of the track coil and the focusing coil in two directions coincide with each other. The optical pickup driving apparatus of claim 1, wherein the track coil is not located between the focusing coil and the permanent magnet formed in the yoke, thereby reducing sensitivity and improving sensitivity. The optical pickup driving apparatus of claim 1, wherein the fixing member is placed on an upper portion of the substrate, and the track coils are formed on a support tool placed on an upper portion of the substrate.