JPH0555316U - Sheet coil - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a sheet coil in which a tensile side insulating sheet does not crack even when attached to a cylindrical holding frame. [Structure] The first sheet body 10a is attached to the insulating sheet 15
In addition, when the second sheet element 10b is sandwiched by the insulating sheet 16 and the sheet coil formed through the adhesive layer 17 is attached to the cylindrical sheet holding frame 20, the insulating sheet 15 on the pulling side is formed. The sheet 15A on the outer peripheral surface is made of a flexible material.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a sheet coil mounted on a cylindrical mounting frame.

[0002]

[Prior Art]

 For example, in an objective lens driving device in an optical pickup used in an optical disk device, a focusing direction driving device including a focusing driving coil and a focusing driving magnet for driving the objective lens in the optical axis direction, and the objective lens in the optical axis direction. There is provided a tracking drive coil for driving in a direction orthogonal to the direction and a drive device in the tracking direction consisting of a tracking drive magnet. Here, the focus drive coil and the tracking drive coil are mounted in a cylindrical shape. It is attached to the frame.

The applicant has previously filed a patent application for an objective lens driving device that is small, highly efficient, has a small number of components, is low in cost, and has high reliability. That is the one described in Japanese Patent Application No. 1-307029, which is a focusing magnet and a tracking magnet, which are arranged on a continuous common surface and are magnetized by being divided in a direction orthogonal to each other. A focusing drive coil and a tracking drive coil, which are arranged on a common continuous surface facing the tracking magnet and the tracking magnet, respectively. The objective lens is moved in the direction of its optical axis by the thrust generated between the two, and the objective lens is moved in the direction perpendicular to its optical axis by the thrust generated between the tracking magnet and the tracking drive coil. It is what

According to the objective lens driving device according to the above application, the magnets are magnetized separately for focusing and tracking, and a dedicated magnetic circuit can be used for each magnet. Since the drive coil for tracking and the drive coil for tracking are arranged on the same plane, the magnetic gap in the part where the coils match becomes small, and a high-density magnetic flux can be obtained, thus providing an objective lens drive device with high efficiency. Obtainable. In addition, since the focusing and tracking magnets, magnetic circuits, and coils can be designed as dedicated parts, performance can be improved by optimizing the design.

[0005]

[Problems to be solved by the device]

 As described above, the objective lens driving device according to the above application has excellent effects, but there is still room for improvement. In other words, since the focus-only drive coil and the tracking-only drive coil are used as separate components and the winding coil is used, the assembly is complicated and the assembly cost is high. There were problems that the gap between the coil and the magnet could not be shortened, the sensitivity was low, the coil easily frayed due to overcurrent, and the reliability was low.

The present invention has been made to address the above problems, and provides a sheet-shaped coil in which a tensile side insulating sheet is prevented from cracking even when mounted on a cylindrical holding frame. In addition, it is easy to assemble, and the assembly cost can be reduced, and there are no winding variations or frays, and the gap between the drive coil and the magnet is reduced to improve sensitivity. It is an object of the present invention to provide a highly reliable objective lens driving device which can be increased in height and has no coil fraying due to overcurrent.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a sheet-shaped coil in which a coil-shaped conductor is sandwiched by an insulating sheet and attached to a cylindrical mounting frame. The insulating sheet is made of a flexible material.

[0008]

[Action]

 Since the tensile side or contracting side insulating sheet is made of a flexible material to form the sheet-shaped coil, even if the sheet-shaped coil is attached to the cylindrical holding frame, No crack occurs even if tensile force is generated. Therefore, the focusing drive coil or the tracking drive coil is exposed, and no disconnection or short-circuit with other parts occurs. Even if the inner peripheral side is compressed so that the outer peripheral side is not burdened, cracks do not occur because the compression-side insulating sheet is made of a flexible material.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing an example in which the sheet-shaped coil of the present invention is applied to an objective lens driving device. Reference numeral 1 denotes an objective lens holder, which has a shaft hole 7 inserted through a fixed shaft. , Is supported so as to be rotatable around the fixed axis and movable along the fixed axis. The objective lens 2 is attached to the objective lens holder 1 with its optical axis parallel to the shaft hole 7. A balancer 8 is attached to the objective lens holder 1 on the opposite side of the objective lens 2 around the shaft hole 7.

The objective lens holder 1 has a partially cylindrical sheet holding frame 20 that is symmetrical with respect to a line connecting the center of the shaft hole 7 and the center of the objective lens 2 and is concentric with the shaft hole 7. On the outer peripheral surface of the sheet holding frame 20, a sheet body 10 in which a focus drive coil 11 and a tracking drive coil 12 are juxtaposed on an insulating sheet is attached by an adhesive. The sheet body 10 has a length from the one sheet holding frame 20 to the other sheet holding frame 20 through the back surface portion of the balancer 8, and the attachment portion to the sheet holding frame 20 is the sheet holding frame 20. A cylindrical shape is formed along the partial cylinder, and an intermediate portion 13 in the longitudinal direction of the sheet body 10 is flat along the back surface portion of the balancer 8. In FIG. 1, reference numeral 21 denotes a part of an adhesive agent for fixing the sheet body 10 to the sheet holding frame 20.

A magnet 6 is fixed by a yoke 9 to the outer peripheral side of the arc-shaped portion of the sheet body 10 along the arc of the sheet holding frame 20. The yoke 9 and the magnet 6 are formed in an arc shape concentric with the arc of the sheet body 10, and the inner peripheral surface of the magnet 6 and the outer peripheral surface of the arc-shaped portion of the sheet body 10 face each other with a predetermined gap. There is. The magnet 6 is integrally formed with, for example, a resin binder. As shown in FIG. 3, the magnet 6 is provided with a groove 6c in a direction parallel to the shaft hole 7 at an intermediate portion in the arc direction. The focus magnet 6a and the tracking magnet are separated by the groove 6c. It is divided into 6b.

The focusing magnet 6a is magnetized so that the N pole and the S pole are lined up in the axial direction, while the tracking magnet 6b is magnetized in a direction orthogonal to the magnetizing direction of the focusing magnet 6a. As a result, the N pole and the S pole are formed in the circumferential direction. In this way, the magnets 6a and 6b are integrally molded and arranged on a continuous common surface.

The focusing magnet 6 a of each magnet 6 faces the focusing drive coil 11 of the sheet body 10, and the tracking magnet 6 b faces the tracking drive coil 12 of the sheet body 10. The yoke 5 is also fixed to the inner peripheral side of the sheet holding frame 20. The yoke 5 is formed integrally with the seat holding frame 20, and the outer periphery of the yoke 5 is formed in an arc that is concentric with the arc of the seat holding frame 20. As shown in FIG. 2, the intermediate portion 13 of the sheet body 10 is provided with terminals 14 for connecting the drive coils 6a and 6b to an external circuit.

Next, a specific example of the sheet body 10 having the drive coils 6a and 6b will be described with reference to FIG. The sheet body 10 is composed of first and second sheet body bodies 10a and 10b. The focus driving coils 11 and the tracking driving coils 12 are formed in a spiral shape by etching or plating on one side and the other side of the base elements 10a and 10b with the intermediate portion 13 as a boundary. .. The focusing drive coils 11 on one side and the other side are connected in series by a connecting conductor pattern 11a, and the tracking drive coils 12 on one side and the other side are also connected in series by a connecting conductive pattern 12a.

Further, the respective sheet bodies 10a and 10b are superposed and adhered to form one sheet body 10, and terminals of a predetermined coil are connected by soldering or the like through the through holes 11a and 11b. Thus, the focus drive coils 11 of the sheet bodies 10a and 10b are connected in series, and the tracking drive coils 12 of the sheet bodies 10a and 10b are connected in series in the same manner. These coil connections may be pattern-connected in parallel according to the required specifications of the DC resistance, etc., in order to obtain an appropriate impedance with the drive circuit.

In this way, one sheet body 10 obtained by stacking and adhering the respective sheet bodies 10a and 10b is fixed to the sheet holding frame 20 along the outer shape thereof as shown in FIG. The coils of the sheet bodies 10a and 10b are densely formed in order to take a large number of turns, but in FIG. 4, they are simplified and drawn roughly. Further, in order to secure a larger number of turns of each coil, one sheet body 10 composed of two sheet body bodies 10a and 10b is further overlapped to form a sheet body composed of four sheet body bodies as a whole. It may be a sheet body or, if necessary, 6 sheet bodies, 8 sheet bodies, ...

FIG. 7 shows a sheet-shaped coil used for such an application. The first and second sheet elements 10a and 10b each have a focus made of a coil-shaped conductor such as a coil wire or a pattern coil. Drive coil 11 and tracking drive coil 12 are formed, which are sandwiched by insulating sheets 15 and 16 and then integrated by an adhesive layer 17. The sheet-shaped coil is attached to the arc-shaped sheet holding frame 20 as shown in FIG.

By the way, in the conventional sheet coil, when attached to a cylindrical sheet holding frame 20 as shown in FIG. 8, a tensile force is generated in the tensile side insulating sheet 15 and a crack 18 is generated. is there. As a result, the focus drive coil 11 or the tracking drive coil 12 is exposed, which causes disconnection or short-circuit with other components.

FIG. 5 shows a cross-sectional structure of the sheet-shaped coil composed of the sheet body 10 shown in FIG. 4. Therefore, after sandwiching the sheet bodies 10a and 10b with the insulating sheets 15 and 16, they are respectively bonded. The sheet is integrated with the agent 17 and attached to the sheet holding frame 20 as shown in FIG. In this case, the insulating sheet 15A on the outer peripheral side of the first sheet element 10a, which is the pulling side, is made of a flexible material. On the other hand, the insulating sheet 15B, which is the intermediate layer, is made of a material having rigidity required as a structural material of the coil. The insulating sheet 16 (16A, 16B) sandwiching the second sheet element 10b is also made of the same material as the insulating sheet 15B.

When a drive current is passed through the focus drive coil 11 via the terminal 11c to the objective lens drive device using the sheet coil as described above, the drive current and the focus magnet 6a are included. Thrust is generated by the magnetic flux in the magnetic circuit. This thrust is evenly generated in the focusing drive coil 11 symmetrically arranged in the track hole 7, and the shaft hole of the lens holder 1 moves along the fixed axis, so that the objective lens 2 moves in the optical axis direction. Then, the focusing operation is performed. When a drive current is passed through the tracking drive coil 12 via the terminal 12c, thrust is generated by this drive current and the magnetic flux in the magnetic circuit including the tracking magnet 6b. This thrust is evenly generated in the tracking drive coil 12 symmetrically arranged in the shaft hole 7, and the objective lens 2 moves together with the lens holder 1 in the direction orthogonal to the optical axis for tracking.

As described above, according to this embodiment, the pulling-side insulating sheet 15A is made of a flexible material to form the sheet-shaped coil, so that the sheet holding frame 20 having the cylindrical shape is seated. Even when the coil-shaped coil is attached, no crack occurs even if a tensile force is generated in the insulating sheet 15A. Therefore, the focus drive coil or the tracking drive coil is exposed, and disconnection or short-circuit with other parts does not occur.

In the present embodiment, the case where the sheet-shaped coil is implemented in the objective lens driving device has been described, but the present invention is not limited to this, and the same can be applied to a case where the sheet-shaped coil is mounted in a cylindrical mounting frame. Further, the insulating sheet 15A on the pulling side is not limited to be made of a flexible material, but the insulating sheet 16B on the inner peripheral surface on the compression side may be made of a flexible material. Both may be made of flexible material.

By forming a sheet-like coil by arranging a flexible material in a portion that is likely to be deformed and a rigid material in an intermediate portion in this way to form a sheet-like coil, the rigidity required for the coil and the flexure when bending are required. It can be balanced with folding endurance.

[0024]

[Effect of the device]

 As described above, according to the present invention, the insulating sheet on the pulling side or the contracting side is made of the flexible material to form the sheet-shaped coil. Therefore, the sheet-shaped coil is formed on the cylindrical holding frame. Even if is attached, even if a tensile force is applied to the insulating sheet on the tension side, cracking does not occur.

[Brief description of drawings]

FIG. 1 is a plan view showing an example in which a sheet coil of the present invention is applied to an objective lens driving device.

2 is a left side view of the embodiment of FIG. 1. FIG.

FIG. 3 is a front view showing the magnet in the embodiment of FIG.

FIG. 4 is a front view showing a sheet-shaped coil in the embodiment of FIG.

5 is a cross-sectional view showing the sheet-shaped coil in the embodiment of FIG.

6 is a cross-sectional view showing a state when the sheet-shaped coil in the embodiment of FIG. 1 is bent.

FIG. 7 is a cross-sectional view showing a conventional sheet coil.

FIG. 8 is a cross-sectional view showing a situation when a conventional sheet coil is bent.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Objective lens 6a Focusing magnet 6b Tracking magnet 10 Sheet body 10a First sheet element body 10b Second sheet element body 11 Focus drive coil 12 Tracking drive coil 15A Tension side insulation sheet 16B Compression side insulation sheet 20 sheet holding frame

Claims (1)

[Scope of utility model registration request] 1. A sheet-shaped coil formed by sandwiching a coil-shaped conductor with an insulating sheet and attached to a cylindrical mounting frame, wherein the insulating sheet on the tension side or the contraction side is made of a flexible material. A sheet-shaped coil characterized in that