KR100358098B1 - Optical pick-up actuator - Google Patents

Abstract

The present invention relates to an optical pickup actuator having a yoke having a magnet fixed to a lens holder and driven by a coil fixed to a base thereof to increase sensitivity and simplify assembly of the lens holder driving unit.

The actuator includes a base having a shaft and a bottom surface supporting the shaft; It is equipped with an objective lens, rotatable about the axis and supported to slide along the axis, attaching the magnet in a direction parallel to the axis, and in a direction parallel to the axis to preserve the magnetic flux density of the magnet. A lens holder having an extended yoke; And a driving coil part including a tracking and focusing coil fixedly installed at a position on the base corresponding to the magnet of the lens holder.

Description

Optical pick-up actuator {Optical pick-up actuator}

The present invention relates to an optical pickup actuator for use in an optical recording / reproducing apparatus for recording or reproducing information on an optical disk through optical means.

Background Art Optical recording and reproducing apparatus for recording and reproducing information by using optical means on a recording medium such as an optical disc has attracted attention as a future storage device. In such an optical recording / reproducing apparatus, the information recording and reading speeds are largely determined by the optical pickup actuators.

The optical pickup actuator includes a lens holder largely equipped with an objective lens, a base for supporting the lens holder in a flowable manner, and lens holder driving means for moving the lens holder in a focusing and tracking direction.

The configuration and operation of the conventional optical pickup actuator as described above will be described below with reference to FIGS. 1 to 4.

1 is a perspective view of a detached state of a lens holder showing a conventional optical pickup actuator, FIG. 2 is a perspective view of an assembled state of the optical pickup actuator illustrated in FIG. 1, and FIG. 3 is a cross-sectional view taken along line a-a 'of the optical pickup actuator illustrated in FIG. 2. 4 is a sectional view taken along the line b-b 'of the optical pickup actuator shown in FIG.

In the drawings, reference numeral 10 is a base member, and 20 is a lens holder.

The base member 10 has an axis 11 that is set up at a predetermined height from its center toward the upper side. The base member 10 is provided with a pair of first yokes 12 and 12 'and a second yoke 13 and 13' at both sides of the shaft 11 at regular intervals. The pair of first yokes 12, 12 'are rectangular in shape, and the second yokes 13, 13' are substantially semi-circular.

In addition, a pair of first magnets 14 and 14 ′ are attached to inner surfaces of the second yokes 13 and 13 ′ so as to face each other at positions corresponding to the first yokes 12 and 12 ′. At a position adjacent to the first magnets 14 and 14 ', a pair of second magnets 15 and 15' having curved portions 15a are attached to face each other. The first and second magnets 14, 14 ′, 15, 15 ′ form a predetermined magnetic circuit, and the first and second yokes 12, 12 ′, 13, 13 ′ are magnets 14, 14. 14 ', 15, 15') magnetic flux density in the direction of the required and maximized.

The lens holder 20 is provided to be movable relative to the base member 10 by fitting the shaft hole 20a formed in the center portion thereof to the shaft 11 of the base member 10.

The lens holder 20 has an objective lens 22 mounted thereon, and a pair of through holes for penetrating the first yokes 12 and 12 'provided at the base member 10 at both sides of the shaft hole 20a. 20b and 20c) are formed.

In addition, the lens holder 20 has a driving coil 30 constituting the lens holder driving means together with the first and second magnets 14, 14 ', 15, and 15'. The driving coil 30 includes a pair of focusing coils 32 and 32 'wound at positions corresponding to the first magnets 14 and 14' on both sides of the lens holder 20 and the lens holder 20 on both sides. And tracking coils 34 and 34 'wound at positions corresponding to the second magnets 15 and 15'. The focusing and tracking coils 32, 32 ′, 34, and 34 ′ are connected to an FPCB 35 to receive a current from the outside.

The optical pickup actuator configured as described above has a magnetic field formed by the magnets 14, 14 ', 15, and 15' fixed to the base 10, and the yokes 12, 12 ', 13, and 13 to which the magnets are attached. The magnetic circuit is formed by '). The focusing and tracking coils 32, 32 ′, 34, 34 ′ are placed in a direction of 90 ° to the magnetic flux vector of the magnetic field, and a current flows from the FPCB 35, which is an external connection line, to focus and track the coils 32, 32, 32 ′, 34, 34 ′. 32 ', 34, and 34' are applied with current to drive tracking and focusing, respectively. However, since the FPCB 35 is connected to the focusing and tracking coils 32, 32 ', 34, and 34', when the lens holder 20 is driven for focusing and tracking servo, the focusing and tracking coil ( 32, 32 ', 34, 34' and magnets 14, 14 ', 15, 15'. Any movement of the FPCB 35 generates negative resonance, which adversely affects the driving characteristics of the lens holder 20.

In addition, since the FPCB connection work, which is the external connection line of the lens holder 20, goes through many difficult processes, the work processability is low and the defect rate is low.

Accordingly, the present invention has been made to solve the above-mentioned problems, an object of the present invention is to provide a lens holder driving unit by having a yoke fixed with a magnet to the lens holder and driven by a coil fixed to the base. An optical pickup actuator can be provided that can increase sensitivity and simplify assembly.

1 is a perspective view of a lens holder separated state showing a conventional optical pickup actuator.

FIG. 2 is an assembled perspective view of the optical pickup actuator of FIG. 1. FIG.

FIG. 3 is a cross-sectional view along the line a-a 'illustrating a main part of the optical pickup actuator of FIG. 2; FIG.

4 is a cross-sectional view taken along the line b-b 'of the optical pickup actuator shown in FIG. 2;

5 is a perspective view showing an optical pickup actuator according to an embodiment of the present invention.

6 is a cross-sectional view taken along line AA ′ of the optical pickup actuator of FIG. 5.

7 is a perspective view showing an optical pickup actuator according to another embodiment of the present invention.

FIG. 8 is a cross-sectional view taken along line BB ′ of the optical pickup actuator of FIG. 7; FIG.

Explanation of symbols on the main parts of the drawings

110; Base member 112; Bottom

114; Axis 120; Lens holder

122, 124; Yoke 125; Axes

126; Magnet 130; Objective

142, 142 '; Focusing coils 144, 144 '; Tracking coil

210; Base member 212; Bottom

214; Axis 220; Lens holder

222; Yoke 225; Axes

226; Magnet 230; Objective

242; Focusing coil 244; Tracking coil

In order to achieve the object as described above, the present invention,

A base having a shaft and a bottom supporting the shaft;

It is equipped with an objective lens, rotatable about the axis and supported to slide along the axis, attaching the magnet in a direction parallel to the axis, and in a direction parallel to the axis to preserve the magnetic flux density of the magnet. A lens holder having an extended yoke;

And a driving coil part including a tracking and focusing coil fixedly installed at a position on the base corresponding to the magnet of the lens holder.

The magnet fixed to the lens holder is installed at a predetermined interval from the yoke inside the yoke. The yoke is shaped like a wedge so that the magnet can optimize the magnetic circuit, and the magnet is attached to the inner wall of the yoke.

The tracking coil of the drive unit is installed so that its winding direction is the radial direction of the shaft and is installed at a position corresponding to the inside of the yoke of the lens holder. The focusing coil of the drive unit is installed so that the winding direction thereof becomes the axial direction and is installed at a corresponding position of the lens holder such that the yoke of the lens holder is inserted into the coil winding.

The yoke may be installed on the opposite side of the objective lens about the axis, wherein the tracking and focusing coil is fixedly installed at a position corresponding to the yoke on the base. Here, the weight of the yoke and the magnet is determined so that the weight of the objective lens and the weight of the yoke with the magnet are balanced with respect to the axis so that the objective lens can be stably rotated about the axis.

Optionally, the yoke may be formed symmetrically on both sides about the axis in a direction orthogonal to the direction in which the objective legs are formed with respect to the axis, wherein the tracking and focusing coils correspond to the yoke on the base. It is fixed to the installation. Here, a weight part is installed on the opposite side of the objective lens about the axis to allow the objective lens to stably rotate about the shaft.

According to the optical pickup actuator, the yoke is formed on the side of the lens holder on which the objective lens is mounted to fix the magnet, and the focusing and tracking coil is fixed on the base at a position corresponding to the yoke of the lens holder on which the magnet is installed. By doing so, when the lens holder is driven in accordance with an externally applied current during focusing and tracking servo, the focusing and tracking coil does not move in a fixed state to the base, so that the driving sensitivity of the lens holder is excellent, and the focusing and tracking coil Since no FPCB, which is an external connection line between the and external cables, is eliminated, the resonance factor is eliminated and the driving characteristics of the lens holder are excellent.

In the magnet attached to the lens holder, the yoke is formed around the magnet so that the magnetic circuit by the magnet can be optimized.

In addition, since the tracking and focusing coils are fixed to the base, the FPCB, which is an external connection line with the focusing and tracking coils, is eliminated, thus eliminating the complicated and defective FPCB connection process, which simplifies the assembly of the optical pickup actuator and the manufacturing yield. There is an effect to be improved.

together. The magnetic fluid viscous material is introduced into the gap between the magnet and the yoke installed inside the yoke to improve the damper effect.

In the case of the slim actuator in which the yoke is installed on the opposite side of the objective lens, the assembly process is simplified because the yoke and the magnet attached to the lens holder can be used to compensate the weight with the objective lens.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Example 1 is a case where the yoke is installed on the lens holder side in a symmetrical form on both sides about the axis, Example 2 is a case where the yoke is installed on the opposite side of the objective lens around the axis.

Example 1

5 is a perspective view illustrating an optical pickup actuator according to an exemplary embodiment of the present invention, and FIG. 6 is a cross-sectional view taken along line AA ′ of the optical pickup actuator of FIG. 5.

In the drawings, reference numeral 110 is a base member, and 120 is a lens holder.

The base member 110 has an axis 114 which is set up at a predetermined height from the center of the bottom face 112 upward.

The lens holder 120 has a shaft hole 125 through which the shaft 114 penetrates. The shaft hole 125 is fitted to the shaft 114 of the base member 110 and is installed to be in a flowable state with respect to the base member 110. That is, the lens holder 120 is installed on the base member 110 in a state of being rotatable about the shaft 114 and slidingly movable along the shaft 114.

The objective lens 130 is mounted on one side of the lens holder 120. A weight portion 126 is provided on the opposite side of the objective lens 130 around the shaft 114 to allow the objective lens 130 to stably rotate about the shaft 114.

In the lens holder 120, yokes 122 and 124 are formed symmetrically on both sides of the shaft 114 in a direction orthogonal to the direction in which the objective legs 130 are formed with respect to the shaft 114. . The yokes 122 and 124 extend in a direction parallel to the axis 114. The magnets 126 are attached to the inside of the yokes 1122 and 124 in a direction parallel to the shaft 114. For example, the yokes 122 and 124 may be integrally formed on the side of the lens holder 120 in a ∩ shape, or may be attached to the side of the lens holder 120 in a ∩ shape. A magnet 126 is attached to the inner wall of the yoke 122, 124, and the yoke shape allows the magnet to optimize the magnetic circuit.

The driving coil portion includes a focusing coil 142 and 142 'and a tracking coil 144 and 144', and is positioned on the bottom 112 of the base member 110 corresponding to the yokes 122 and 124 and the magnet 126. It is fixed to the installation.

The focusing coils 142 and 142 ′ of the driving coil portion are installed so that their winding directions are axial, and the ends extending in the axial direction of the yokes 122 and 124 of the lens holder 120 are focused on the focusing coil 142. 142 ') is installed at a corresponding position of the lens holder 120 to be inserted into the winding.

The tracking coils 144 and 144 'of the driving coil portion are installed such that their winding directions are perpendicular to the axis 114, that is, the radial direction, and at the same time inside the yokes 122 and 124 of the lens holder 120. It is installed at the corresponding position.

The magnetic fluid viscous material is introduced into the gap between the magnets 126 and the yokes 122 and 124 provided inside the yokes 122 and 124 to improve the damper effect.

In the optical pickup actuator configured as described above, a magnetic field is formed by the magnet 126 fixed to the lens holder 120, and the magnetic circuit is formed by the yokes 122 and 124 to which the magnet 126 is attached. The focusing and tracking coils 142, 142 ′, 144, and 144 ′ fixedly installed on the bottom surface 112 of the base member 110 are placed in a direction 90 ° to the magnetic flux vector of the magnetic field, and the base member 110. Current is supplied from an external connection circuit (not shown) connected to the current and applied to the focusing and tracking coils 142, 142 ′, 144, and 144 ′, respectively, to drive the tracking and focusing servos.

According to the optical pickup actuator according to the present embodiment, the yoke (122, 124) extending in the axial direction on the side of the lens holder 120 mounted with the objective lens 130, and the yoke (122, 124) Fix the magnet 126 inside the installation. In addition, the focusing and tracking coils 142, 142 ′, 144, and 144 ′ on the bottom surface of the base member 110 at positions corresponding to the yokes 122 and 124 of the lens holder 120 provided with the magnet 126. Fix it. Therefore, the focusing and tracking coils 142, 142 ′, 144, and 144 ′ move in a fixed state to the base member 110 when the lens holder 120 is driven according to an externally applied current during focusing and tracking servo. Therefore, the driving sensitivity of the lens holder 120 is excellent. In this case, since the FPCB, which is an external connection line with the focusing and tracking coils used in the conventional axial optical pickup actuator, is not required, the negative resonance factor is eliminated and the driving characteristics of the lens holder are further improved.

The side of the lens holder 120 is integrally formed or attached to the Y-shaped yoke extending in the axial direction, the magnet 126 is attached to the inside of the yoke (122, 124). Thus, the yoke of this shape surrounding the magnet 126 makes it possible to optimize the magnetic circuit by the magnet.

In addition, since the tracking and focusing coils are fixed to the base, the FPCB, which is an external connection line with the focusing and tracking coils, is eliminated, thus eliminating the complicated and defective FPCB connection process, which simplifies the assembly of the optical pickup actuator and the manufacturing yield. There is an effect to be improved.

together. The magnetic fluid viscous material is introduced into the gap between the magnet and the yoke installed inside the yoke to improve the damper effect.

Example 2

FIG. 7 is a perspective view illustrating an optical pickup actuator according to another exemplary embodiment of the present invention, and FIG. 8 is a cross-sectional view taken along line B-B ′ of the optical pickup actuator of FIG. 7.

In the figure, reference numeral 210 is a base member, and 220 is a lens holder.

The base member 210 has an axis 214 set up at a predetermined height from the center of the bottom surface 212 toward the upper side.

A shaft hole 225 through which the shaft 214 penetrates is formed in the lens holder 220. The shaft hole 225 is fitted to the shaft 214 of the base member 210 is installed so as to be in a flowable state with respect to the base member 210. That is, the lens holder 220 is installed on the base member 210 in a state of being rotatable about the shaft 214 and slidingly movable along the shaft 214.

An objective lens 230 is mounted on one side of the lens holder 220. The yoke 222 is formed on the opposite side of the objective lens 230 with respect to the axis 214. The yoke 222 has an end extending in a direction parallel to the axis 214. The magnet 226 is attached to the inside of the yoke 222 in a direction parallel to the shaft 214. For example, the yoke 222 may be integrally formed in one side of the lens holder 220 in a ∩ shape, or may be attached to the side of the lens holder 220 in a ∩ shape. A magnet 226 is attached to the inner wall of the yoke 222, and the jaw shape allows the magnet 226 to optimize the magnetic circuit. The weight of the yoke 222 and the magnet 226 attached to the lens holder 220 is adjusted to be in equilibrium with the weight of the objective lens 230 about the axis 214, so that the objective lens 230 is stably Allows rotational movement about axis 214.

The driving coil part includes a focusing coil 242 and a tracking coil 244, and is fixedly installed at a position corresponding to the yoke 222 and the magnet 226 on the bottom surface 212 of the base member 210.

The focusing coil 242 of the driving coil part is installed so that its winding direction is axial direction, and one end extending in the axial direction of the yoke 222 of the lens holder 220 is inserted into the focusing coil 242 winding. It is installed at the corresponding position of the lens holder 220 to be.

The tracking coil 244 of the driving coil part is installed such that its winding direction is a direction orthogonal to the shaft 214, that is, a radial direction, and is installed at a position corresponding to the inside of the yoke 222 of the lens holder 220. do.

The magnetic fluid viscous material is introduced into the gap between the magnet 226 and the yoke 222 installed inside the yoke 222 to improve the damper effect.

In the optical pickup actuator configured as described above, the magnetic field is formed by the magnet 226 fixed to the lens holder 220, and the magnetic circuit is formed by the yoke 222 to which the magnet 226 is attached. The focusing and tracking coils 242 and 244 fixedly installed on the bottom surface 212 of the base member 210 are placed in a direction 90 ° to the magnetic flux vector of the magnetic field, and are connected to an external connection circuit connected to the base member 210. Current comes from (not shown) and current is applied to the focusing and tracking coils 242 and 244, respectively, to drive for tracking and focusing servos.

According to the optical pickup actuator according to the present embodiment, the yoke 222 having an end extending in the axial direction is provided on the side of the lens holder 220 on which the objective lens 230 is mounted. Fix the magnet 226 inside. In addition, the focusing and tracking coils 242 and 244 are fixed to the bottom surface of the base member 210 at a position corresponding to the yoke 222 of the lens holder 220 in which the magnet 226 is installed. Therefore, the focusing and tracking coils 242 and 244 do not move in a fixed state to the base member 210 when the lens holder 220 is driven according to an externally applied current during focusing and tracking servo. ) Excellent driving sensitivity. In this case, since the FPCB, which is an external connection line with the focusing and tracking coils used in the conventional axial optical pickup actuator, is not required, the negative resonance factor is eliminated and the driving characteristics of the lens holder are further improved.

The side of the lens holder 220 is formed integrally formed or attached to the ∩ yoke that is extended in the axial direction, the magnet 226 is attached to the inside of the yoke 222. Thus, the yoke of this shape surrounding the magnet 226 makes it possible to optimize the magnetic circuit by the magnet.

In addition, since the tracking and focusing coils are fixed to the base, the FPCB, which is an external connection line with the focusing and tracking coils, is eliminated, thus eliminating the complicated and defective FPCB connection process, which simplifies the assembly of the optical pickup actuator and the manufacturing yield. There is an effect to be improved.

together. The magnetic fluid viscous material is introduced into the gap between the magnet and the yoke installed inside the yoke to improve the damper effect.

In the optical pickup actuator configured as described above, the magnetic field is formed by the magnet 226 fixed to the lens holder 220, and the magnetic circuit is formed by the yoke 222 to which the magnet 226 is attached. Focusing and tracking coils 242 and 244 fixedly installed on the bottom 212 of the base member 210 are placed in a direction of 90 ° to the magnetic flux vector of the magnetic field, and are connected to an external connection circuit connected to the base member 210. Current comes from (not shown) and current is applied to the focusing and tracking coils 242 and 244, respectively, to drive for tracking and focusing servos.

According to the optical pickup actuator according to the present embodiment, the yoke 222 extending in the axial direction is formed on the side of the lens holder 220 mounted with the objective lens 230, the magnet inside the yoke 222 Securely mount (226). In addition, the focusing and tracking coils 242 and 244 are fixed to the bottom surface of the base member 210 at a position corresponding to the yoke 222 of the lens holder 220 in which the magnet 226 is installed. Therefore, the focusing and tracking coils 242 and 244 do not move in a fixed state to the base member 210 when the lens holder 220 is driven according to an externally applied current during focusing and tracking servo. ) Excellent driving sensitivity. In this case, since the FPCB, which is an external connection line with the focusing and tracking coils used in the conventional axial optical pickup actuator, is not required, the negative resonance factor is eliminated and the driving characteristics of the lens holder are further improved.

The side of the lens holder 220 is formed integrally formed or attached to the ∩ yoke that is extended in the axial direction, the magnet 226 is attached to the inside of the yoke 222. Thus, the yoke of this shape surrounding the magnet 226 makes it possible to optimize the magnetic circuit by the magnet.

In addition, since the tracking and focusing coils are fixed to the base, the FPCB, which is an external connection line with the focusing and tracking coils, is eliminated, thus eliminating the complicated and defective FPCB connection process, which simplifies the assembly of the optical pickup actuator and the manufacturing yield. There is an effect to be improved.

together. The magnetic fluid viscous material is introduced into the gap between the magnet and the yoke installed inside the yoke to improve the damper effect.

Therefore, according to the optical pickup actuator according to the present invention as described above, a yoke extending in the axial direction is formed on the side of the lens holder on which the objective lens is mounted, and the magnet is fixedly installed inside the yoke. Further, a focusing and tracking coil is fixedly installed on the bottom of the base member at a position corresponding to the yoke of the lens holder provided with the magnet. Therefore, when the lens holder is driven according to an externally applied current during focusing and tracking servo, the focusing and tracking coil does not move in a fixed state to the base member, so the driving sensitivity of the lens holder is excellent. In this case, since the FPCB, which is an external connection line with the focusing and tracking coils used in the conventional axial optical pickup actuator, is not required, the negative resonance factor is eliminated and the driving characteristics of the lens holder are further improved.

The side of the lens holder is integrally formed or attached to the w-shaped yoke, the end of which extends in the axial direction, and a magnet is attached to the inside of the yoke. Thus, the yoke of this shape surrounding the magnet makes it possible to optimize the magnetic circuit by the magnet.

In addition, since the tracking and focusing coils are fixed to the base, the FPCB, which is an external connection line with the focusing and tracking coils, is eliminated, thus eliminating the complicated and defective FPCB connection process, which simplifies the assembly of the optical pickup actuator and the manufacturing yield. There is an effect to be improved.

together. The magnetic fluid viscous material is introduced into the gap between the magnet and the yoke installed inside the yoke to improve the damper effect.

In the case of the slim actuator in which the yoke is installed on the opposite side of the objective lens, the assembly process is simplified because the yoke and the magnet attached to the lens holder can be used to compensate the weight with the objective lens.

Claims (9)

delete delete A base having a shaft and a bottom supporting the shaft; It is equipped with an objective lens, is rotatable about the axis and supported to be slidable along the axis, attaches the magnet in a direction parallel to the axis, and the magnet is installed at a predetermined interval inside the magnetic circuit of the magnet. A lens holder having a yoke extending in a direction parallel to the axis formed in a shape of a shape so as to optimize And a drive coil portion including a tracking and focusing coil fixedly installed at a position on the base corresponding to the magnet of the lens holder. delete 4. The optical pickup actuator according to claim 3, wherein the focusing coil of the driving unit is installed so that its winding direction is axial and that the yoke of the lens holder is inserted into the coil holder so as to be inserted into the coil winding. 4. The optical pickup actuator of claim 3, wherein the yoke may be installed on an opposite side of the objective lens about an axis, and the tracking and focusing coil may be fixedly installed at a position corresponding to the yoke on a base. 7. The method of claim 6, wherein the weight of the yoke and the magnet is determined so that the weight of the objective lens and the weight of the yoke with the magnet are balanced with respect to the axis so that the objective lens can be stably rotated about the axis. Optical pickup actuator characterized in that. delete 4. The yoke of claim 3, wherein the yoke may be symmetrically formed on both sides of the axis in a direction orthogonal to the direction in which the objective lens is formed, wherein the tracking and focusing coils correspond to the yoke on a base. An optical pick-up actuator, characterized in that the fixed portion is installed in the position opposite the objective lens around the axis so that the objective lens can be stably rotated about the axis.