KR20050030018A - Very small molded coil device for actuator, and optical pickup apparatus and optical disc drive using the same - Google Patents

Abstract

A VSMCD(Very Small Molded Coil Device) for an actuator, an optical pickup device adopting the VSMCD, and an optical disk drive are provided to integratedly form a coil and a yoke in non-magnetic and insulating material package, thereby mitigating restrictions on a driving range caused by interference between the yoke and the coil. A VSMCD(10) consists of a coil(11) and a yoke(14) inserted into a body(12). The body(12) is made of a non-magnetic/insulating material such as a ceramic material. The coil(11) is a conductor where a current flows, and a plane thereof is in square shape to be used for an actuator. The yoke(14) forms a magnetic circuit such that a magnetic force line of a magnet(1) can be orthogonal with the coil(11), and is made of a ferromagnetic material. Terminals(13) for supplying currents to the coil(11) are disposed in both side sections of the body(12). The coil(11) is a non-magnetic material.

Description

Very small molded coil device for actuator, and optical pickup apparatus and optical disc drive using the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil device of an actuator using electromagnetic force induced by the interaction between a magnet and a coil through which a current flows, and an optical disk drive employing the same.

Actuators using electromagnetic force have been applied to optical pickup devices of optical disk drives, magnetic head drive devices of hard disk drives, pickup devices of magneto-optical disk drives, and the like.

In general, an optical disc drive is a device for recording or reproducing information by irradiating light to an optical disc, which is a recording medium, and for reproducing the information. For this purpose, a spindle motor for rotating an optical disc and a recording surface of the optical disc are irradiated with light. An optical pickup device for performing a job is provided.

In general, an optical pickup apparatus is provided with an optical pickup actuator for controlling the position of the objective lens in a focusing direction and a tracking direction so that light can be focused on a desired track on an optical disk recording surface. As a result, the distance between the objective lens and the optical disk recording surface is kept constant so that the focus of the optical spot is maintained and the optical spot follows the desired track.

The optical pickup actuator is usually provided with a coil on a blade on which an objective lens is mounted, and a magnet is installed to face the coil on a base on which the blade is elastically movable. When a current is supplied to the coil, electromagnetic force is generated by interaction with the magnetic field formed by the magnet. The magnitude of the electromagnetic force F is calculated by Lorenz's formula F = BL x i. Where B is the strength of the magnetic field, L is the effective length of the coil, and I is the amount of current. By driving the blade using this principle, the distance between the objective lens and the optical disc recording surface is constantly adjusted to maintain the focus of the optical spot and control the optical spot to follow the desired track.

As Lorentz's formula shows, it is most desirable that the magnetic field of the magnet and the current of the coil are orthogonal. Since the line of magnetic force bends away from the magnet, it is necessary to place the magnet and coil as close as possible. However, in this case, the driving range of the blade is limited by the interference between the coil and the magnet. In addition, the yoke may be provided at a position facing the magnet to straighten the lines of magnetic force. The yoke is installed on the base. The yoke is preferably installed as close to the coil as possible to increase magnetic efficiency. In this case, however, the driving range of the blade is limited. Moreover, since the yoke and the coil may interfere with each other due to an error generated when assembling the yoke and the coil, the driving range of the blade is further limited within the range considering this error. In addition, the winding coils generally used have rounded corners, and are limited in the number of turns of the coil due to size and weight constraints, making it very difficult to increase the effective length of the coil for inducing electromagnetic force.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has been developed to reduce the limitation of the driving range of the coil due to the interference between the magnet and the coil or the coil and the yoke (VSMCD: very) It is an object of the present invention to provide a small molded coil device) and an optical disk drive having the same. Another object of the present invention is to provide an ultra small molded coil device (VSMCD) for an actuator and an optical disk drive having the same, which can be improved to increase an effective length of a coil for inducing electromagnetic force. Another object of the present invention is to provide an ultra small molded coil device (VSMCD) for an actuator and an optical disk drive having the same, which can be improved to increase self-use efficiency.

The micro mold coil device of the present invention for achieving the above object, the micro mold coil device for an actuator for inducing electromagnetic force by interaction with the magnetic field of the magnet, at least one coil; And a yoke for forming a magnetic circuit such that the magnetic force lines of the magnet cross substantially perpendicularly to a current flowing through the coil, wherein the coil and the yoke are packaged with a nonmagnetic and insulating material to be integrally formed.

The optical pickup device of the optical disk drive of the present invention for achieving the above object is mounted on a base relative to the optical disk to record / reproduce information on the optical disk, the optical module and the optical output from the optical module. An objective lens for forming an optical spot on the optical medium, and an optical pickup actuator for controlling a position of the objective lens so that the light is irradiated to a desired position on the optical disc, wherein the optical pickup actuator includes the objective lens. A blade mounted to be supported to be elastically flowable to the base by a plurality of suspension wires; A magnetic member installed on the base; At least one coil member installed on the blade to generate an electromagnetic force by interaction with the magnetic member, the coil member comprising: at least one coil; And a yoke for forming a magnetic circuit such that the magnetic force lines of the magnet cross substantially perpendicularly to a current flowing through the coil, wherein the coil and the yoke are packaged with a nonmagnetic and insulating material to be integrally formed.

The optical disk drive of the present invention for achieving the above object is mounted on a spindle motor for rotating the optical disk, and a base mounted relative to the optical disk to irradiate light to the optical disk through an objective lens to record or reproduce information. An optical disc drive comprising an optical pickup device for controlling a position of the objective lens to irradiate a desired position on the optical disc with the light, wherein the optical pickup actuator includes a plurality of the optical lens units. A blade supported to be elastically flowable to the base by a suspension wire of the base; A magnetic member installed on the base; At least one coil member installed on the blade to generate an electromagnetic force by interaction with the magnetic member, the coil member comprising: at least one coil; And a yoke for forming a magnetic circuit such that the magnetic force lines of the magnet cross substantially perpendicularly to a current flowing through the coil, wherein the coil and the yoke are packaged with a nonmagnetic and insulating material to be integrally formed.

According to an embodiment, the yoke may be a multilayer yoke in which two or more flat yokes are stacked. Further, according to another embodiment, the yoke may be a loop yoke.

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

1 and 2 are horizontal cross-sectional and vertical cross-sectional views, respectively, showing an embodiment of a micro mold coil device according to the present invention.

Referring to FIG. 1, the micro mold coil device 10 includes a coil 11 and a yoke 14 embedded in the body 12. The body 12 is formed of a nonmagnetic, insulating material such as a ceramic material, for example. The coil 11 is a conductor through which a current flows, and in order to be used in an actuator, the coil 11 preferably has a rectangular shape as shown in FIG. 2. The yoke 14 is for forming a magnetic circuit so that a magnetic force line by the magnet 1 is orthogonal to the coil 11, and is a magnetic substance, more preferably a ferromagnetic material. Terminals 13 for supplying current to the coil 11 are provided at both sides of the body 12. The coil 11 is preferably nonmagnetic.

The feature of the micro mold coil device 10 of the present embodiment is that the coil 11 and the yoke 14 have a structure in which the coil 12 and the yoke 14 are integrally embedded in the body 12 made of a nonmagnetic, insulating material. Therefore, the distance between the coil 11 and the yoke 14 can be made very close. In addition, when the electromagnetic force is induced by the interaction between the magnetic force of the magnet 1 and the current supplied to the coil 11, as shown in FIG. 1, since the micro mold coil device 10 itself moves, the coil 11 ) And yoke 14 move together. As shown by a dotted line in FIG. 1, when the yoke 14a is spaced apart from the coil 11, only the coil 11 moves. Then, the strength of the magnetic field reaching the yoke 14a changes according to the movement of the coil 11, and the force applied to the coil 11 is unbalanced, and a rotation moment may be generated in the coil 11. The yoke 14a is induced with an eddy current which hinders the change of this magnetic field. Eddy current has a negative effect in controlling the operation of the coil 11. However, according to the micro-molded coil device 10 of the present embodiment, since the yoke 14 moves together with the coil 11, the magnet 1 may be applied to the yoke 14 when the magnet 1 is sufficiently large compared to the coil 11. The strength of the magnetic field of the magnet 1 hardly changes. Therefore, the effective length of the coil 11 becomes long and there is little risk of generating a rotation moment. In addition, when the shape of the yoke 14 is a laminated type or a loop type which will be described later, it is possible to further reduce the generation of eddy current which adversely affects the operation of the coil 11.

3 to 6 show various modifications of the yoke in the micro mold coil device according to the present invention. The same components as those described in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant descriptions are omitted.

First, referring to FIGS. 3 and 4, a modified example of the yoke for reducing the negative effect of the eddy current is shown. 3, the micro mold coil device 20 includes a laminated yoke 24. Referring to FIG. 4, the micro mold coil device 30 includes a loop yoke 34. The laminated yoke 24 refers to a laminate in which two or more thin flat yokes are insulated from each other. The laminated yoke 24 can increase the magnetic efficiency by reducing the loss of eddy current generated by the magnetic force lines of the magnet 1. The loop yoke 34 increases the amount of saturation magnetic flux of the line of magnetic force of the magnet 1 to increase the self utilization efficiency.

In addition, according to the mutual arrangement of the coil 11 and the magnet 1, the inner yoke 44 and the back yoke 54 are properly provided as shown in FIGS. 5 and 6. Micro mold coil devices 40 and 50 may also be considered. The inner yoke 44 and the back yoke 54 may be the stacked yoke 24 or the looped yoke 34 shown in FIGS. 3 and 4. The inner yoke 44 increases the inductance to increase the sensitivity of the actuator.

FIG. 7 is a block diagram showing another embodiment of the micro mold coil device according to the present invention, and FIG. 8 is a vertical cross-sectional view of FIG.

As shown in FIG. 7, the micro mold coil device 100 may include a plurality of electrically independent coils 110, 120, 130 embedded in the body 160. Reference numerals 141, 142, and 143 are terminals for supplying current to the coils 110, 120, and 130, respectively. 8, the yoke 150 is provided at one side of each of the coils 110, 120, and 130. Yoke 150 may be a laminated yoke 24 or a looped yoke 34 as shown in FIGS. 3 and 4. The micro mold coil device 100 can be driven three-dimensionally by controlling the direction of the current applied to each of the coils 110, 120, and 130 by such a configuration.

9 is a perspective view illustrating an embodiment of an optical disk drive according to the present invention, and FIG. 10 briefly illustrates an example of an optical configuration of the optical pickup apparatus shown in FIG. 9. The optical configuration of the optical pickup device of the optical disc drive is not limited to the optical configuration shown in FIG.

9, the main frame 500 is mounted on the spindle motor 510 for rotating the optical disk D and the base 300 relative to the optical disk D to record / reproduce information on the optical disk D. The optical pickup device 520 is installed. The base 300 is supported to be slidable by a pair of guide shafts 530 installed in the radial direction of the optical disc D on the main frame 500, for example, as shown in FIG.

The spindle motor 510 rotates the optical disc D, and the turntable 511 on which the optical disc D is seated is coupled to the rotation axis of the spindle motor 510. The optical pickup device 520 irradiates light to the optical disc D through the objective lens 330 to record information on the optical disc D or to reproduce information stored on the optical disc D.

Referring to FIG. 10, an optical module 521 for emitting light having a predetermined wavelength, a grating 522 for branching light incident from the optical module 521 into 0th order and ± 1th order, and the optical module 521 A collimating lens 523 for converting the divergent light emitted from the light into parallel light, an objective lens 330 for forming light into an optical spot on the recording surface of the optical disc D, and an optical disc D. The main photodetector 527 is shown for receiving the light reflected from the recording surface of the < RTI ID = 0.0 >

Reference numeral 524 denotes that the light emitted from the optical module 521 is incident to the objective lens 330 and the light reflected from the optical disk D and passed through the objective lens 330 to the main photodetector 527. It is a beam splitter. A concave lens 526 may be interposed between the beam splitter 524 and the main photodetector 527. The concave lens 526 is for removing astigmatism.

The beam splitter 525 branches a portion of the light directed to the objective lens 330 and enters the front photodetector 528. Front photodetector 528 detects power from this light. If the detected light output is below or exceeds a predetermined level, the output of the optical module 521 is adjusted to allow light having a predetermined level of power to be incident on the optical disc D.

The objective lens 330 needs to be driven at least in the focusing direction Z and the tracking direction X in order to ensure that the light is accurately incident on a desired position on the optical disc D, and in some cases, the tilt direction T It also needs to be driven. The optical pickup device is provided with an optical pickup actuator to drive the objective lens 330.

FIG. 11 is a plan view illustrating an embodiment of an optical pickup actuator. FIG.

Referring to FIG. 11, a blade 320 mounted with a base 300 and an objective lens 330 is illustrated.

The base 300 is provided with a plurality of yokes 381 and 382 and a pair of magnets 340 as magnetic members for providing magnetic force. The magnet 340 of this embodiment is installed so that the N poles face each other.

The base 300 is provided with a holder 301. The blade 320 is provided with a plurality of hinges 321. One end of the plurality of suspension wires 390 is connected to the holder 301 and the other end is connected to the hinge 321, so that the blade 320 is elastically supported relative to the base 300.

The blade 320 may be provided with a plurality of coil members for generating electromagnetic force by interaction with the magnet 340. The optical pick-up actuator has a case of having a zoom focus coil and a tracking coil, a case having a zoom focus coil and a tracking coil, the focus coil also serves as a tilt coil, and a zoom focus coil, a tracking coil and a tilt coil, respectively. There is a case. In the present embodiment, an optical pick-up actuator of the Q type will be described.

The blade 320 is provided with two focusing coils 350 and tracking coils 360. As the focus coil 350, a very small mold coil device 40 having an inner yoke 44 as shown in FIG. 5 may be used. As the tracking coil 360, the micro mold coil devices 10, 20, 30 shown in FIGS. 1, 3, and 4 may be used. The blade 320 is usually manufactured by plastic injection molding, in which the focus coil 350 and the tracking coil 360 may be integrally formed with the blade 320 by insert molding. .

The two focus coils 350 are installed in a horizontal direction symmetrically about the objective lens 330. Only two sides 351 and 352 facing the magnet 340 of the focus coil 350 are used as an effective part for generating the electromagnetic force. When the currents supplied to the two focus coils 350 are made the same, electromagnetic forces Fz in the same direction are induced to the two focus coils 350, and the blade 320 is driven in the focus direction Z. When the currents in the opposite directions are supplied to the two focus coils 350, electromagnetic forces Fz in the opposite directions are induced to the two focus coils 350, so that the blade 320 is driven in the tilt direction T.

The tracking coil 360 is for generating an electromagnetic force Fx in the tracking direction X by interaction with the magnet 340, and is perpendicular to two sides facing the magnet 340 of the blade 320. Once installed. In some cases, it may be installed only on either side. Two sides 361 of the tracking coil 360 are used as an effective part for generating the electromagnetic force Fx.

12 is a plan view illustrating another embodiment of the optical pickup actuator, and FIG. 13 is a cross-sectional view taken along line II-II 'of FIG. 11.

Referring to FIG. 11, there is shown a blade 320 that is elastically supported by a suspension wire 390 on a base 300. The base 300 is provided with a pair of magnets 341 bipolarized left and right facing each other. The coil member 200 is installed on both side surfaces of the blade 320 that face the magnet 341. As the coil member 200, the micro mold coil device 100 shown in FIGS. 7 and 8 is used. The micro mold coil device 100 may be integrally formed with the blade 320 by insert injection molding.

Referring to FIG. 13, the coil 120 and the coil 130 are for driving the focusing direction Z and the tilt direction T, and the sides 121 and 131 of the coils 120 and 130 may have electromagnetic force ( It is used as a valid part for generating Fz). Accordingly, the N pole and the S pole of the magnet 341 are provided to face the two sides 121 and 131, respectively. When the current is supplied to the coils 120 and 130 so that the current flows in the same direction to the two sides 121 and 131, the coils 120 and 130 generate the electromagnetic force Fz in opposite directions, respectively. 320 is driven in the tilt direction (T). When current is supplied to the coils 120 and 130 so that current flows in opposite directions to the two sides 121 and 131, the electromagnetic force Fz in the same direction is generated in the coils 120 and 130 so that the blades ( 320 is driven in the focusing direction Z.

The coil 110 is for driving in the tracking direction X, and the left and right sides 113 and 114 are used as an effective part for generating an electromagnetic force. Therefore, the north pole and the south pole of the magnet 341 are provided to face the two sides 113 and 114, respectively. The electromagnetic force Fx in the tracking direction X is generated in the coil 110 by controlling the direction of the current supplied to the coil 110.

Wound coils or planar coils are mainly used for optical pickup actuators. The wound coil has a tendency to round the corners when the coil is wound around the rectangular bobbin, so that the direction of the current does not cross perpendicularly to the direction of the magnetic field at the corners. This tendency gets worse as the number of turns increases. In addition, since the thickness of the wire is limited, to increase the effective length of the coil is bound to increase the number of turns. In this case, the size of the coil may be increased and the weight may be increased, thereby reducing driving sensitivity of the optical pickup actuator. Since the planar coil uses the same method as the conventional PCB manufacturing, even if it is multi-layered, the number of layers is limited to about 8 layers, so there is a limit to increasing the number of turns of the coil. In addition, in the case of a flat coil, a problem of lifting the substrate and the coil may occur.

By employing the micro mold coil device according to the present invention, these disadvantages can be overcome or alleviated. A chip inductor or chip bead, a circuit element for a surface mounting device (SMD), is manufactured using screen printing and lamination, and according to the present invention, a very small mold coil device Can be produced by this production method. Therefore, if it is the same size as the wound coil, the number of turns of the coil can be increased and the corner portion can be formed almost at right angles as compared with the wound coil, so that the effective length of the coil for generating the electromagnetic force can be increased. In the case of having the same number of coil turns as the wound coil, the size can be reduced compared to the wound coil, and the actuator can be made smaller and lighter.

In addition, by employing the micro mold coil device having the yoke integrated, the magnetic force lines can be straightened so that the magnetic force lines and the current flowing through the coils are perpendicular to each other. Therefore, in driving the blade, the limitation of the driving range due to the distance between the magnet and the coil can be relaxed. In addition, by minimizing the distance between the coil and the yoke can improve the self-use efficiency and driving sensitivity.

In the above, the case where the micro mold coil device according to the present invention is applied to the optical disk drive has been described, but the scope of the present invention is not limited thereto. The micro mold coil device according to the present invention can be applied to various actuators for generating electromagnetic force by interaction with a magnet, such as a magnetic head drive device of a hard disk drive, a pickup device of a magneto-optical disk drive, and an electronic device having the same. .

As described above, according to the micro mold coil device for an actuator according to the present invention, by forming the yoke integrally with the coil, the magnetic force line passing through the coil can be straightened and the self-use efficiency can be improved. In addition, according to the optical disk drive employing the micro mold coil device according to the present invention, it is possible to reduce the size and weight of the actuator, and to reduce the distance between the magnet, coil, and yoke without risk of interference between the coil and the yoke. Self-use efficiency and driving sensitivity can be improved.

It is to be understood that the invention is not limited to that described above and illustrated in the drawings, and that more modifications and variations are possible within the scope of the following claims.

1 and 2 are horizontal cross-sectional and vertical cross-sectional views, respectively, showing one embodiment of a micro mold coil device according to the present invention;

3-6 show various modifications of the yoke in the micro mold coil device according to the invention.

7 is a schematic view showing another embodiment of the micro mold coil device according to the present invention.

8 is a vertical sectional view of FIG.

9 is a perspective view showing one embodiment of an optical disk drive according to the present invention;

10 is a configuration diagram schematically illustrating an example of an optical configuration of the optical pickup device shown in FIG. 9;

FIG. 11 is a plan view illustrating one embodiment of the optical pickup actuator shown in FIG. 9; FIG.

12 is a plan view showing another embodiment of the optical pickup actuator shown in FIG.

FIG. 13 is a cross-sectional view taken along line II-II 'of FIG. 11;

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

10,20,30,40,50,110 ...... Miniature Mold Coil Device

11,110,120,130 ...... Coil 12 ...... Body

13 ...... Terminal 14 ...... York

24 ...... Laminated yoke 34 ...... Looped yoke

44 ...... Inside yoke 54 ...... White yoke

300 ...... Base 320 ...... Blade

330 ...... Objective lens 340,341 ...... Magnet

Claims (9)

An ultra-small mold coil device for an actuator that induces electromagnetic force by interaction with a magnetic field of a magnet, At least one coil; And a yoke for forming a magnetic circuit such that the magnetic force lines of the magnet cross substantially perpendicularly to a current flowing through the coil. And the coil and the yoke are packaged with a nonmagnetic, insulating material to form an integrally molded coil device for an actuator. The method of claim 1, And said yoke is a multilayer yoke in which two or more flat yokes are laminated. The method of claim 1, And said yoke is a loop type yoke. Mounted on a base relative to the optical disc and recording / reproducing information on the optical disc, wherein the optical module, an objective lens for causing light emitted from the optical module to form light spots on the optical medium, and An optical pickup actuator which controls a position of the objective lens to irradiate a desired position on the optical disc, The optical pickup actuator, A blade mounted with the objective lens and supported to be elastically flowable to the base by a plurality of suspension wires; A magnetic member installed on the base; Is installed on the blade includes at least one coil member for generating an electromagnetic force by interaction with the magnetic member, the coil member, At least one coil; And a yoke for forming a magnetic circuit such that the magnetic force lines of the magnet cross substantially perpendicularly to a current flowing through the coil, wherein the coil and the yoke are packaged with a nonmagnetic and insulating material and formed integrally. Optical pickup device. The method of claim 4, wherein And the yoke is a multilayer yoke in which two or more flat yokes are stacked. The method of claim 4, wherein And the yoke is a loop type yoke. A spindle motor for rotating an optical disc and a base mounted relative to the optical disc to record or reproduce information by irradiating light to the optical disc through an objective lens so that the light is irradiated to a desired position on the optical disc. An optical disc drive comprising an optical pickup apparatus having an optical pickup actuator for controlling a position of a lens, wherein the optical pickup actuator includes: A blade mounted with the objective lens and supported to be elastically flowable to the base by a plurality of suspension wires; A magnetic member installed on the base; Is installed on the blade includes at least one coil member for generating an electromagnetic force by interaction with the magnetic member, The coil member includes at least one coil; And a yoke for forming a magnetic circuit such that the magnetic force lines of the magnet cross substantially perpendicularly to a current flowing through the coil, wherein the coil and the yoke are packaged with a nonmagnetic and insulating material and formed integrally. . The method of claim 7, wherein And the yoke is a multilayer yoke in which two or more flat yokes are stacked. The method of claim 7, wherein And the yoke is a loop type yoke.