KR100547359B1 - Optical pickup actuator wherein winding coil are replaced with printed circuit baord, optical pickup apparatus and manufacturing method thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup actuator in which a winding coil is replaced with a printed circuit board among optical pickup actuator module components using a printed circuit board technology, an optical pickup apparatus equipped with the actuator, and a method of manufacturing the same.

An actuator for optical pickup according to the present invention includes two printed circuit boards including a tracking circuit pattern and a focusing circuit pattern; An objective lens attaching portion disposed between the two printed circuit boards; And a magnetic material for applying a magnetic field to the two printed circuit boards.

Bobbin, Printed Circuit Board, Focusing, Tracking

Description

Optical pickup actuator wherein winding coil are replaced with printed circuit baord, optical pickup apparatus and manufacturing method

1 shows a schematic structure of a conventional optical pickup apparatus.

2 is an exploded perspective view showing the components of the conventional optical pickup actuator separately.

3 is a view for explaining the operation of the bobbin using a printed circuit board according to the present invention.

4 is a schematic diagram of a bobbin and a permanent magnet using a printed circuit board technology according to the present invention.

5a to 5e show a method of manufacturing a bobbin incorporating a winding coil according to the present invention.

※ Description of the main parts of the drawings

401 bobbin

402: objective lens

403 and 407: printed circuit board

404, 406, 408, 410: Circuit pattern for focusing

405, 409: Circuit pattern for tracking

411, 412: Permanent Magnet

413a, 413b: wire

The present invention relates to an optical pickup actuator in which a winding coil is replaced with a printed circuit board, an optical pickup apparatus equipped with the actuator, and a manufacturing method thereof.

More specifically, the present invention relates to an optical pickup actuator in which a winding coil is replaced with a printed circuit board among optical pickup actuator module components using a printed circuit board technology, an optical pickup apparatus equipped with the actuator, and a manufacturing method thereof. .

1 shows a schematic structure of a conventional optical pickup apparatus.

As shown in FIG. 1, in general, the optical pickup device 10 is assembled to the main shaft 3 and the sub-shaft 5 provided on the deck panel 1 of the optical driver, and reciprocates along the axial direction. A device for reproducing a signal recorded in D) or recording a signal on an optical disk, wherein the optical pickup device 10 is coupled to the main axis and the minor axis to reciprocate along the axial direction, and an upper surface of the base 30. The actuator 20 is composed of an actuator 20 that converges to a point of the optical disk by converging the incident light beam while moving with the base 30.

2 is an exploded perspective view showing the components of the conventional optical pickup actuator separately.

Referring to Fig. 2, the conventional actuator 20 is described. The bobbin 22 having the objective lens 21 on its upper surface is focused so that it can be finely moved in the focusing direction, that is, the vertical direction and the tracking direction, that is, the left and right directions. The coil 23 and the tracking coil 24 are wound in a copper wire, and a magnetic body 27 and a yoke 28 for generating an electromagnetic force are provided around these coils.

In addition, the bobbin 22 is elastically supported by the wire holder 26 through a wire 25 extending horizontally in the tracking direction. That is, one end of the wire 25 is soldered to both sides of the bobbin 22, and the other end of the wire 25 is fixed to the wire holder 26 so that the bobbin 22 is moved up, down, left and right by the elastic force of the wire 25. It is possible to move finely.

The actuator 20 configured as described above moves the objective lens 21 in the focusing or tracking direction by electromagnetic force when power is applied to each coil through the wire 25.

The actuator module using the winding coil is a technology that has been used for a long time. The principle of Lorentz force is used to move the bobbin, and the winding coil is used for this principle. Electric current flows through the winding coil made of copper copper wire, and the Lorentz force is generated by the influence of the magnetic field of the permanent magnet located in front of the coil, so that the bobbin can move up and down, left and right. At this time, in order to separately adjust the movement of the up and down, left and right winding coils are arranged together with the permanent magnet.

With the advancement of the industry, miniaturization of electronic products is progressing, and the market demands actuators that can be applied to small and thin electronic products. At this time, the existing actuator module is wound so that the winding coil is located on the side of the bobbin and the required sensitivity is obtained. In order to require a winding coil of more than a certain size, the limit on the miniaturization of electronic products is encountered. In addition, assembling a number of parts has a problem that the process is complicated and the defect rate is large accordingly.

In addition, in the conventional winding coil, there is a problem that a phenomenon in which the copper wire of the winding coil is cut frequently occurs.

In addition, in order to reduce the size of the actuator, a permanent magnet having a complex polarization is used according to the arrangement of the coil in order to reduce the volume. In the manufacture of such a permanent magnet, not only the manufacturing cost increases but also a high level of difficulty is required.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical pickup actuator in which a winding coil is replaced with a printed circuit board-type coil among module components of a conventional optical pickup actuator using a printed circuit board manufacturing technology, and a method of manufacturing the same.

It is still another object of the present invention to provide an optical pickup actuator and a method for manufacturing the same, in which the number and weight of components are greatly reduced by replacing the winding coil used in the conventional optical pickup apparatus with a printed circuit board using a printed circuit board manufacturing technology. To provide.

Still another object of the present invention is to provide an actuator for optical pickup using a printed circuit board technology having a higher sensitivity than a conventional winding coil because of its light weight, and moving the lens in up, down, left and right directions.

It is still another object of the present invention to provide an actuator for an optical pickup and a method of manufacturing the same, including a stable circuit having excellent heat resistance and durability that are not broken even during product operation.

It is still another object of the present invention to provide an actuator for optical pickup and a method of manufacturing the same, in which a winding coil in which the manufacturing process and the unit cost are greatly reduced by completing the manufacturing of the actuator module only by attaching the lens to the integrated bobbin and attaching the wire. It is.

Another object of the present invention is to replace the winding coil attached to the side of the bobbin with a four-layered printed circuit board coil made of a printed circuit board, and also to realize the coil configuration in a spiral shape more turns than conventional The present invention provides an actuator for an optical pickup and a method of manufacturing the same, which can form water, which in turn improves sensitivity characteristics.

Another object of the present invention is to solve the problem that it is difficult to reduce the thickness of the conventional bobbin any more due to the winding coil, by arranging the existing thick winding coil in parallel with the bobbin by using a printed circuit board, It is to provide an actuator for thin optical pickup that can significantly reduce the size and ultimately meet the trend of miniaturization of electronic products.

An actuator for optical pickup according to the present invention includes two printed circuit boards including a tracking circuit pattern and a focusing circuit pattern; An objective lens attaching portion disposed between the two printed circuit boards; And a magnetic material for applying a magnetic field to the two printed circuit boards.

In addition, the optical pickup device according to the present invention, two printed circuit board including a tracking circuit pattern and a focusing circuit pattern; A bobbin disposed between the two printed circuit boards; And a magnetic body disposed outside the two printed circuit boards and configured to apply a magnetic field to the two printed circuit boards. A wire connected to an electrode provided on the printed circuit board to supply current to the focusing circuit pattern and the tracking circuit pattern, the wire having elasticity; And it characterized in that it comprises a holder for supporting the wire.

In addition, the printed circuit board manufacturing method replacing the winding coil for the optical pickup actuator according to the present invention comprises the steps of: processing via holes for electrically connecting the tracking circuit pattern and the focusing circuit pattern to the printed circuit board; Electrolytic copper plating both surfaces of the printed circuit board and the inner wall of the via hole; Forming an etching resist pattern including a tracking circuit pattern and a focusing circuit pattern on both sides of the printed circuit board; Etching the printed circuit board; Forming solder resist patterns on both sides of the printed circuit board; And cutting the printed circuit board to a bobbin size.

3 is a view for explaining the operation of the bobbin using a printed circuit board according to the present invention.

A printed circuit board 301 including two focusing circuit patterns 302 and 304 and a tracking circuit pattern 303, and a magnetic body 308 polarized in the form of six magnets pasted together are shown in FIG. As opposed to each other. The two focusing circuit patterns 302 and 304 are disposed at both ends of the printed circuit board 301 and between the tracking circuit patterns 303.

The focusing circuit patterns 302 and 304 and the tracking circuit pattern 303 are formed in the form of a spiral coil wound around an imaginary axis perpendicular to both the focus direction and the track direction.

A circuit pattern having the same shape is formed on the back surface of the printed circuit board 301, and the circuit patterns (not shown), the focusing circuit patterns 302 and 304, and the tracking circuit pattern 303 formed on the back surface are the centers of the spiral circuit patterns. It is connected to each other by via holes 305, 306, 307 formed in the.

A magnetic field is generated around the magnet. If a current flows through a straight wire (coil) placed in the magnetic field, the current flows through the Lorentz law according to Fleming's left-hand rule.

F = B I l sinθ (N)

Where F is the Lorentz force (N), B is the magnetic density (Wb / m ² or T), I is the magnitude of the current (A), l is the length of the conductor in the magnetic field (m), and θ is Is the angle between the direction and the direction of the current.

The direction of the force received by the conductor is perpendicular to the plane of the direction of the current and the magnetic field, and when the direction of the current or the magnetic field is reversed, the direction of the force received by the conductor is also reversed.

This principle is used to drive the actuator. When two conductors with opposite directions of current are in close proximity, the Lorentz forces cancel each other out and disappear, resulting in weak sensitivity. Therefore, in order not to dissipate Lorentz forces, magnetic fields in opposite directions should be applied to two regions in which the currents in the coils are opposite to each other.

The focusing circuit pattern 302 of FIG. 3 is composed of a, b, c, and d portions forming a rectangle. The portion a is affected by the magnetic field by the first polarization portion 308a of the permanent magnet 308, and the portion c is affected by the magnetic field by the second polarization portion 308b. Assuming that a clockwise current flows in the focusing circuit pattern 302, the circuit pattern in the a and c portions is subjected to Lorentz force in the direction of the arrow 309.

The upper part of the b, d part is affected by the magnetic field by the first polarization part 308a of the permanent magnet 308, and the lower part is affected by the magnetic field by the second polarization part 308b, but the b, d part is Lorentz's force on the circuit pattern is canceled at the top and bottom, respectively. Therefore, the circuit patterns of the b and d portions do not contribute to the focusing operation.

The tracking circuit pattern 303 of FIG. 3 also consists of a, b, c, d portions that form a rectangle. The circuit pattern of the portion d is affected by the magnetic field by the third polarization portion 308c of the permanent magnet 308, and the circuit pattern of the portion b is affected by the magnetic field by the fourth polarization portion 308d. Assuming that a clockwise current flows in the tracking circuit pattern 303, the circuit pattern of the b and d portions receives the Lorentz force in the direction of the arrow 310.

The left side of the a, c part is affected by the magnetic field by the third polarization part 308c of the permanent magnet 308, and the right side is affected by the magnetic field by the fourth polarization part 308d, but the a, c part Lorentz's force on the circuit pattern is canceled because it is reversed on its left and right sides, respectively. Therefore, the circuit patterns of the a and c portions do not contribute to the tracking operation.

Similarly, the focusing circuit pattern 304 of FIG. 3 is composed of a, b, c, and d portions forming a rectangle. The portion a is affected by the magnetic field by the fifth polarization portion 308e of the permanent magnet 308, and the portion c is affected by the magnetic field by the sixth polarization portion 308f. Assuming that a counterclockwise current flows through the focusing circuit pattern 304, the circuit pattern in the a and c portions is subjected to Lorentz force in the direction of the arrow 309.

The upper part of the b, d part is affected by the magnetic field by the fifth polarization part 308e of the permanent magnet 308, and the lower part is affected by the magnetic field by the sixth polarization part 308f, but the b, d part is The Lorentz forces of the circuit pattern are canceled out because they are opposite each other at the top and bottom. Therefore, the circuit patterns of the b and d portions do not contribute to the focusing operation.

In FIG. 3, a clockwise current flows through the focusing circuit pattern 302 and the tracking circuit pattern 303, and a counterclockwise current flows through the focusing circuit pattern 304. However, this setting can be changed according to the polarization direction of the permanent magnet 308 to generate the desired focusing and tracking direction force.

The current is electrically connected to the circuit pattern and may be supplied through a separate electrode (not shown) formed on the printed circuit board 301.

4 is a schematic diagram of a bobbin and a permanent magnet using a printed circuit board technology according to the present invention.

The bobbin 401 and the objective lens 402 are disposed at the center thereof, and printed circuit boards 403 and 407 having focusing circuit patterns 404, 406, 408 and 410 and tracking circuit patterns 405 and 409 respectively on both sides thereof. ) Is placed. In addition, polarized permanent magnets 411 and 412 are arranged on the outer side of each other, as if six flat permanent magnets were formed to form a magnetic field.

The bobbin 401, the printed circuit boards 403, 407, and the permanent magnets 411, 412 are connected to each other by wires 413a, 413b, 413c, 413d which are elastic with each other, and the wires are physically supported by an external holder (not shown). do.

In the state as shown in FIG. 4, a clockwise current flows through the focusing circuit pattern 404 and the tracking circuit pattern 405 of the printed circuit board 403, and a counterclockwise current flows through the focusing circuit pattern 406. Assuming that a permanent magnet 411 that is flowing and polarized as shown in FIG. 4 is disposed, the focusing circuit patterns 404 and 406 are forced in the direction of the arrow 414, and the tracking circuit pattern 405 is indicated by the arrow 415. Force in the direction of).

Similarly, a clockwise current flows through the focusing circuit pattern 408 and the tracking circuit pattern 409 of the printed circuit board 407, and a counterclockwise current flows through the focusing circuit pattern 410, as shown in FIG. 4. Assuming that the polarized permanent magnet 412 is disposed, the focusing circuit patterns 408 and 410 are forced in the direction of the arrow 414 'and the tracking circuit pattern 409 is forced in the direction of the arrow 415'. Receive.

As a result, in the state shown in Fig. 4, the printed circuit boards 403 and 407 are forced in the directions of arrows 414 and 415, and are physically connected to the printed circuit boards 403 and 407 by the wires 413a, 413b, 413c and 413d. Bobbin 401 is also connected to receive the force in the same direction.

In Fig. 4, the magnitudes of the currents applied to the focusing circuit patterns 404, 406, 408, and 410 of both printed circuit boards 403, 407 may be varied. If the magnitudes of the currents are different from each other, the bobbin 401 may be slightly inclined with respect to the focus direction, and the disk tilt may be compensated by adjusting the magnitude of the currents.

In addition, the printed circuit board in place of the winding coil according to the present invention is a double-sided printed circuit board having a focusing circuit pattern and a tracking circuit pattern on both sides, as well as the same focusing circuit pattern and tracking circuit pattern formed on the inner layer circuit 4 Multi-layer printed circuit boards of more than one layer can be used.

5a to 5e show a method of manufacturing a bobbin incorporating a winding coil according to the present invention.

5A is a cross-sectional view of a copper clad laminate (CCL) 501 before being processed. Copper foil 502 is coated on the insulating layer 503.

There are various kinds of copper foil laminates such as glass / epoxy copper clad laminate, heat resistant resin copper clad laminate, paper / phenol copper clad laminate, high frequency copper clad laminate, flexible copper clad laminate (polyimide film) and composite copper clad laminate. Preference is given to using glass / epoxy copper foil laminates which are mainly used in the manufacture of double-sided PCBs and multilayer PCBs.

In Fig. 5B, via-holes 504a, 504b, and 504c for electrically connecting the focusing circuit pattern and the tracking circuit pattern to be formed on both sides by drilling are formed in the copper-clad laminate 501.

In FIG. 5C, a copper plating layer 505 is formed on both sides of the substrate and inside the via holes by electroless copper plating and electrolytic copper plating. At this time, electroless copper plating is performed first, followed by electrolytic copper plating. In FIG. 5C, an electroless copper plating layer and an electrolytic copper plating layer 505 are shown as one layer. The reason why electroless copper plating is performed before electrolytic copper plating is that electrolytic copper plating that requires electricity cannot be performed on the insulating layer. That is, in order to form the electroconductive film required for electrolytic copper plating, electroless copper plating is thinly performed as the pretreatment.

Such via holes should be filled with a filling material, but can be filled with a separate filling process. However, since the via holes 504a, 504b, and 504c have small diameters, the electroless copper plating and the electrolytic copper plating process may be performed without a separate filling process. It is preferable to fill the inside of the via hole.

In Fig. 5D, a pattern of the etching resist 509 for forming the focusing circuit pattern and the tracking circuit pattern is formed.

In order to form a resist pattern, a circuit pattern printed on an artwork film must be transferred onto a substrate. There are various methods of transferring, but the most commonly used method is a method of transferring a circuit pattern printed on an artwork film by ultraviolet light to a dry film using a photosensitive dry film. In this case, LPR (Liquid Photo Resist) may be used instead of the dry film.

In Fig. 5E, when the substrate is immersed in the etchant, the spiral coil-shaped focusing circuit patterns 511 and 513 and the tracking circuit pattern 512 are formed.

Various post treatments such as surface treatment of the formed circuit pattern may be used in a conventional printed circuit board manufacturing method.

In the optical pickup actuator in which the winding coil according to the present invention is replaced with a printed circuit board, the number and weight of components are greatly reduced by replacing the conventional winding coil with a printed circuit board.

In addition, the optical pickup actuator in which the winding coil according to the present invention is replaced with a printed circuit board has a significantly reduced weight, so that the sensitivity of moving the objective lens in the track direction and the focus direction is superior to that of the conventional winding coil. As the number of parts decreases, the manufacturing cost can be lowered.

In addition, a conventional bobbin using a winding coil requires components and manufacturing processes such as a bobbin itself and a mold for the bobbin, a winding coil, a winding coil winding, a lens attachment, and a wire solder, whereas the winding coil according to the present invention is a printed circuit. Optical pickup actuators replaced with substrates can significantly reduce the manufacturing process and unit cost because the manufacturing of actuator modules is completed only by attaching lenses and attaching wires.

In the conventional bobbin, the thickness is no longer reduced due to the winding coil, but in the optical pickup actuator in which the winding coil according to the present invention is replaced with a printed circuit board, the printed circuit board coil is disposed in parallel with the bobbin. The thickness of the bobbin can be significantly lowered. Therefore, it is possible to cope with the demand for thin actuator according to the trend of miniaturization of electronic products.                     

In the optical pickup actuator in which the winding coil according to the present invention is replaced with a printed circuit board, it is possible to minimize the defect of the finished product due to the breakage of copper wire generated in the conventional winding coil.

In addition, the printed circuit board type coil of the optical pickup actuator according to the present invention has a spiral shape, and since the circuit pattern is formed in a straight line, the degree of movement of the objective lens mounted in the bobbin in the vertical direction is higher than that of the winding coil. Has excellent characteristics.

In addition, the printed circuit board-type coil of the optical pickup actuator according to the present invention can be all the defects in the circuit formation state by the electrical short-circuit inspection before final appearance processing.

The thickness of the bobbin using the conventional winding coil (about 5.0mm) is difficult to reduce due to the winding coil, the coil using the printed circuit board according to the present invention only the bobbin thickness of more than (0.4 ~ 0.6mm) polarization area of the permanent magnet As a result, it is possible to meet the demand for thin actuators according to the trend of miniaturization of electronic products.

Claims (17)

Two multilayer printed circuit boards comprising a tracking circuit pattern and a focusing circuit pattern; A bobbin disposed between the two multilayer printed circuit boards; And An actuator for optical pickup disposed outside the two multilayer printed circuit boards and including a magnetic material for applying a magnetic field to the two multilayer printed circuit boards. The optical pickup actuator of claim 1, wherein the tracking circuit pattern and the focusing circuit pattern are formed in a spiral coil shape wound around an axis perpendicular to both the tracking direction and the focusing direction. The optical pickup actuator of claim 1, wherein the magnetic material is a plate-shaped permanent magnet disposed outside each of the multilayer printed circuit boards in parallel with a tracking direction. The optical pickup actuator of claim 1, wherein the magnetic material is polarized such that a force in a focusing direction is applied when a current flows in a focusing circuit pattern of the multilayer printed circuit board. The optical pickup actuator of claim 1, wherein the magnetic material is polarized such that a force in a tracking direction is applied when a current flows in the tracking circuit pattern of the multilayer printed circuit board. The optical pickup actuator of claim 1, wherein the multilayer printed circuit board is a double-sided printed circuit board. delete The optical pickup actuator of claim 1, wherein the magnetic material is polarized in the form of a combination of six small magnetic plates in a plate polarized into the N pole and the S pole, respectively. Two multilayer printed circuit boards comprising a tracking circuit pattern and a focusing circuit pattern; A bobbin disposed between the two multilayer printed circuit boards; And A magnetic material disposed outside the two multilayer printed circuit boards and configured to apply a magnetic field to the two multilayer printed circuit boards; A wire connected to an electrode provided on the multilayer printed circuit board to supply current to the focusing circuit pattern and the tracking circuit pattern, the wire having elasticity; And And a holder for supporting the wire. The optical pickup apparatus of claim 9, wherein the tracking circuit pattern and the focusing circuit pattern are formed in a spiral coil shape wound around an axis perpendicular to both the tracking direction and the focusing direction. 10. The optical pickup apparatus of claim 9, wherein the magnetic material is a plate-shaped permanent magnet disposed outside each of the multilayer printed circuit boards in parallel with a tracking direction. The optical pickup apparatus of claim 9, wherein the magnetic material is polarized such that a force in a focusing direction is applied when a current flows in a focusing circuit pattern of the multilayer printed circuit board. The optical pickup apparatus of claim 9, wherein the magnetic material is polarized such that a force in a tracking direction is applied when a current flows in the tracking circuit pattern of the multilayer printed circuit board. The optical pickup apparatus of claim 9, wherein the multilayer printed circuit board is a double-sided printed circuit board. delete 10. The optical pickup apparatus of claim 9, wherein the magnetic material is polarized in the form of a combination of six small magnetic plates in a plate polarized into the N pole and the S pole, respectively. Processing via holes for electrically connecting the tracking circuit pattern and the focusing circuit pattern to the printed circuit board; Electrolytic copper plating both surfaces of the printed circuit board and the inner wall of the via hole; Forming an etching resist pattern including a tracking circuit pattern and a focusing circuit pattern on both sides of the printed circuit board; Etching the printed circuit board; Forming solder resist patterns on both sides of the printed circuit board; And Actuator manufacturing method for an optical pickup comprising the step of cutting the printed circuit board to a bobbin (Bobin) size.

Images