KR100438276B1 - Optical pick-up actuator for radial tilting drive - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an actuator in which radial tilting is possible with driving in a focusing and tracking direction, in particular, and an optical pickup actuator capable of radial tilting driving according to the present invention includes a lens holder having an asymmetrical structure. An optical pickup actuator having a movable part and a fixed part, comprising: a radial magnet formed in a tracking direction on both sides of the lens holder, and a radial coil disposed on a yoke opposite to the radial magnet and fixed to a yoke fixed to a pickup base; It features.

According to the present invention, by forming a radial magnetic circuit consisting of a horizontal magnet or a vertically polarized radial magnet and a coil opposite thereto for radial driving in the left and right tracking directions of the lens holder, driving control in the focusing and tracking directions and In addition, the present invention provides a three-axis actuator capable of driving control in a radial tilt direction.

Description

Optical pick-up actuator for radial tilting drive

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup actuator. In particular, an optical pickup capable of radial tilting driving together with focusing and tracking driving is provided by placing a magnetic circuit for focusing and tilt driving at the center and a magnetic circuit for tracking driving at left and right sides. It relates to an actuator.

In general, an objective lens driving device which drives an optical spot to follow the center of a signal track of an optical disk with respect to the surface vibration and eccentricity of the optical disk due to the rotation of the optical disk with the light beam collected from the objective lens is driven together with the optical pickup. do.

The objective lens driving apparatus is called an optical pickup actuator and drives the objective lens to perform focusing and tracking operations. The focusing operation is to drive the objective lens up and down so that the light spot of the light beam from the objective lens falls within the depth of focus in the signal track of the optical disc, and the tracking operation is that the light spot of the light beam from the objective lens is a signal of the optical disc. The track is driven left and right to follow the center.

A general optical pickup actuator uses a coil and a magnet to move the objective lens up and down (focusing servo) and left and right (tracking servo) by the current flowing through the coil and the electromagnetic force between the magnets. Currently, the optical pickup has high sensitivity and high driving characteristics. , Is in the trend of thinning.

In the conventional optical pickup actuator employing a two-axis linear motion wire method and a leaf spring method, in order to reduce the height of the optical pickup, the optical path from the laser diode light source must be formed on the same plane as the optical pickup actuator. do. In this case, since there are magnetic circuits such as a magnet, a focusing coil, and a tracking coil for focusing and tracking operations on the optical path from the laser diode, there is a problem in that the actuator is thinned. In addition to the thinning of the optical pickup actuator, the situation is required to increase the stability and high accuracy due to the high speed.

The conventional optical pickup actuator will be described with reference to FIG. 1 as follows. 1 is a plan view of an optical pickup actuator viewed from an information recording surface of an optical disc.

Referring to FIG. 1, an objective lens 11 for condensing a light beam from a laser diode light source onto an information recording surface of an optical disc, a lens holder 12 for mounting and moving the objective lens 11 to a protrusion, and the lens The magnet 13 inserted into the inner hole of the holder 12 and fixed to the pickup base, and the yoke 14 positioned on the rear surface of the magnet 13 to prevent magnetic flux leaking out of the rear surface of the magnet 13. ), A tracking coil 15 facing the magnet 13 and wound around the inner diameter surface of the lens holder 12, and a focusing coil wound around the inner diameter surface of the lens holder 12 at a right angle to the tracking coil 15. 16).

Further, a wire spring 17 is provided on the left and right sides of the lens holder 12 to supply current to the tracking coil 15 and the focusing coil 16 and to support the lens holder 12.

Referring to the attached optical pickup actuator as described above with reference to the accompanying drawings as follows.

First, the lens holder 12 attaches the objective lens 11 to the protrusion to avoid the optical path from the light source.

Through the objective lens 11, the lens holder (for the focus direction driving to focus the light beam is perpendicularly irradiated to the disk surface and the track direction driving to focus according to the track signal recorded on the disk) 12 inserts a magnet 13 and a yoke 14 forming a magnetic circuit in the center thereof to form a magnetic circuit in its inner diameter.

The tracking coil 15 is wound around the hole of the lens holder 12, and the focusing coil 16 is wound around the inner side of the hole of the lens holder 12 at a right angle to the tracking coil 15.

In the wire spring 17, the lens holder 12 has fixed points at both left and right sides, and the up and down and left and right movements of the optical pickup actuator according to the tracking operation and the focusing operation are driven in two axes based on the end portion of the wire spring 17. It is done if possible.

In addition, the lens holder 12 having the objective lens 11 attached to the protruding portion constitutes a magnet 13, a yoke 14, a tracking coil 15, and a focusing coil 16 for focusing and tracking. The lens 11 is driven up, down, left and right.

The driving force of the optical pickup actuator forms a tracking coil 15 and a focusing coil 16 in a magnetic space formed by the magnet 13 and the yoke 14 to control power in the focus direction and the track direction. 16), it operates under Lorentz force according to Fleming's left hand law according to its power supply.

In addition, the yoke 14 is made of a magnetic body of a steel system and is located on the rear surface of the magnet 13.

The optical pick-up actuator driven by the magnetic force in the up-down (focusing) direction and the left-right (tracking) direction generated in such a magnetic circuit has an up-down movement, a left-right movement with the axis of the tip of the wire spring 17 fixed to the fixed portion as an axis. To perform the focusing operation and the tracking operation.

Generally, the playback signal is read by the control power in two directions (tracking and focusing), and the central axis of the light beam deviates from the perpendicular state to the disk plane by the self-rotating component when the disk or the actuator with large deflection is driven. do. This causes the playback signal to deteriorate during playback, thereby degrading the playback capability.

In addition, the tilt margin gradually decreases for high density disks, in which the actuator requires precision, and now the assembly has reached a limit that cannot meet the optical tilt tolerance.

Therefore, in recent years, the optical pickup actuator requires a three-axis actuator configuration to follow the disturbance of the radial tilting in addition to the focusing and tracking two-axis servo, and the configuration of the actuator capable of driving in three axes is required.

In addition, the conventional configuration of the actuator in the desktop space has a high degree of freedom in design spatially can configure the actuator drive system in a variety of directions, the existing concept was able to configure a three-axis actuator. However, due to the constraint that the path of light and the actuator must overlap each other as the product becomes thinner gradually, the existing two-axis actuator has been configured to avoid magnetic circuits and protrude the objective lens in the part where the light path passes as shown in FIG. In the same structure, the configuration of the magnetic circuit becomes more difficult for tilt driving.

The present invention has been made to solve the above problems, for the purpose of radial tilt driving in the structure of the two-axis actuator protruding the objective lens in a thin slim structure, the magnetic force in different vertical directions in parallel with the track direction Focusing and tracking drive is generated at the center of the lens holder and radial magnetic circuits generating magnetic force in the horizontal direction opposite to the track direction are formed at the left and right sides of the lens holder. In addition, to provide an optical pickup actuator capable of radial tilting drive.

1 is a plan view for explaining a conventional optical pickup actuator.

2 is a plan view of an optical pickup actuator capable of a radial tilting drive according to an embodiment of the present invention.

3 is a view showing a radial tilting drive in an optical pickup actuator according to an embodiment of the present invention.

4 is a plan view of an optical pickup actuator capable of a radial tilting drive according to another embodiment of the present invention.

5 is a view showing a radial tilting drive in an optical pickup actuator according to another embodiment of the present invention.

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

11,111,211 ... objective lens 12,112,212 ... lens holder

13,113,213 ... Magnet 14,114,214,121,221 ... York

15,115,215 ... Tracking Coil 16,116,216 ... Focusing Coil

17,117,217 ... wire suspension 118 ...

119,219 Radial magnet 120,220 Radial coil

Optical pickup actuator capable of radial tilting drive according to the present invention for achieving the above object, in the optical pickup actuator having a lens holder having a non-symmetrical structure, and a movable portion and a fixing portion, the tracking direction on both sides of the lens holder And a radial coil disposed on the yoke fixed to the pick-up base and opposed to the radial magnet. The radial magnet is unipolarized so that the lens holder is parallel to the tracking direction. The radial magnet is multipolarized and attached to the lens holder opposite to the tracking direction. The following description will be made with reference to the accompanying drawings.

2 is a plan view showing an optical pickup actuator capable of tilt driving according to the first embodiment of the present invention, Figure 3 is a view for explaining the principle of operation of the first embodiment of Figure 2, Figure 4 is a first embodiment of the present invention FIG. 5 is a plan view showing an optical pickup actuator capable of tilt driving according to a second embodiment, and FIG. 5 is a view for explaining the principle of operation according to the second embodiment of FIG.

In the first embodiment, as shown in FIGS. 2 and 3, a lens holder 112 for mounting and moving the objective lens 111 to a protrusion, and a magnet for tracking and focusing installed around the hole in the lens holder 112, are provided. 113, the yoke 114, the tracking and focusing coils 115 and 116, and the left and right sides of the lens holder 112 in the vertical direction in the tracking direction to move the lens holder 112 in the radial direction. It is composed of a radial magnet 119 and a coil 120 installed.

The radial magnet 119 is installed at the left and right feathers 118 of the lens holder 112, and the radial coil 120 opposite thereto is fixed to the pick-up base 122 with a screw 123. It is the configuration wound on (121).

4 and 5, the radial magnet 219 vertically polarized on the left and right sides of the lens holder 212 is fixed, and the radial coil 220 opposite thereto is fixed to the pickup base. to be.

Referring to the accompanying drawings, the optical pickup actuator capable of driving the radial tilting according to the present invention configured as described above will be described below with reference to the same parts as those of the prior art.

First embodiment;

2 and 3, the objective lens 111 is attached to the protrusion of the lens holder 112, and the magnets 113 facing each other before and after the holes processed inside the lens holder are picked up. It is attached to the yoke 114 fixed to the base.

Then, the focusing coil 116 is wound around the hole and the tracking coil 115 is wound vertically with the focusing coil 116. That is, the tracking coil 115 is configured to face the magnet 113 by vertical winding in the tracking direction.

As described above, the lens holder 112 moves in the tracking direction according to the power applied to the tracking magnetic circuit including the magnet 113, the yoke 114, and the tracking coil 115, and the magnet 113 and the yoke 114. ) And the focusing coil 116 moves in the focusing direction according to the power applied to the focusing magnetic circuit.

The left and right sides of the lens holder 112 extend the feather 118, and the radial magnet 119 is attached to the feather 118 in a direction perpendicular to the tracking direction, so as to face the radial magnet 119. The configured radial coil 120 is wound around the yoke 121 fastened by the screw 123 to the pickup base 122.

Then, the radial tilting of the lens holder 112 by the magnetic force generated by the radial magnet 119 and the coil 120 on the left and right sides of the lens holder 112 according to the power applied to the radial coil 120. Will be moved in the direction.

This operating principle is to polarize the polarity of the radial magnet 119 attached to the left and right sides of the lens holder 112 in the horizontal direction as shown in FIG. ) Is configured such that the left and right sides are equal to each other, and reverses the direction of the current applied to the radial coil 120, thereby performing a tilting operation in which the left side of the lens holder 112 moves upward and the right side moves downward. do.

In addition, as shown in FIG. 3 (b), the magnetic poles N: S of the radial magnets 119 attached to the left and right sides of the lens holder are multipolarized in the horizontal direction, and the polarities opposite to the radial coil 120 are left and right. The right (N: S, S: N) is configured differently and the same direction of the current applied to the radial coil 120, the left side of the lens holder 112 is moved upward, the right side is moved downward Perform a tilting operation.

In this embodiment, the tilting in the opposite direction to that of FIG. 3 (a) (b) is made by the tilt servo through the polarity of the radial magnet 119 and the direction of the current applied to the radial coil 120. The tilt angle can be adjusted by the amount of current that is applied.

Second embodiment;

A second embodiment of the present invention will be described with reference to FIGS. 4 and 5. Here, the configuration of the tracking and focusing magnetic circuit is the same as that of the first embodiment, and the configuration of the radial tilt magnetic circuit multiplies the radial magnet 219 vertically in the tracking direction on the left and right sides of the lens holder 212 (N: S), and the radial coil 220 is fixed to the pickup base so as to face the radial magnet 219.

Referring to FIG. 5, the operation principle of the radial magnetic circuit is illustrated in FIG. 5A to magnetize the polarities of the left and right radial magnets 219 to N: S, and to change the current direction applied to the radial coil 220. On the contrary, a tilting operation is performed such that the left side of the lens holder 212 moves downward and the right side moves upward.

5 (b) shows that the polarities of the left and right radial magnets 219 are differently magnetized to N: S and S: N, and the radial magnets 219 when the current directions applied to the radial coils 220 are the same. Due to the magnetization of different polarities (N: S, S: N), a tilting operation is performed in which the left side of the lens holder 212 moves downward and the right side of the lens holder 212 moves upward.

According to the second embodiment of the present invention, the tilt servo is operated in a direction opposite to that of FIG. 5A and 5B according to the polarity of the radial magnet 219 on the left and right sides of the lens holder and the current direction applied to the radial coil 220. By the tilting operation.

As described above, the radial magnet 219 is radially tilted together with the lens holder 212 by the total magnetic force generated by the radial magnetic circuit configuration consisting of the radial magnet 219 and the coil 220 to the left and right sides of the lens holder 212. While moving in the direction, tilt adjustment of the objective lens 211 is made possible.

According to the optical pickup actuator capable of tilting driving according to the present invention as described above, a radial magnetic circuit is formed on the left and right sides of the lens holder, so that the multipolar magnetization in the direction perpendicular to the tracking direction or the multipolar magnetization in the vertical direction By using the magnet and the coil opposite to it, the radial tilting drive is possible, so that the tilt servo can be controlled for the rotational component of the optical pickup actuator so that the central axis of the light beam can always be perpendicular to the disk plane. Can improve.

Claims (3)

An optical pickup actuator having a lens holder having an asymmetrical structure, a movable part, and a fixed part, And a radial magnet formed in a tracking direction on both sides of the lens holder, and a radial coil disposed to be wound around a yoke fixed to a pickup base and opposed to the radial magnet. The method of claim 1, And the radial magnet is monopolarized and attached to the lens holder parallel to the tracking direction. The method of claim 1, And the radial magnet is polarized and attached to the lens holder opposite to the tracking direction.