KR100288418B1 - Axis Type Optical Pickup Actuator with Magnetic Circuit - Google Patents

Abstract

The present invention is to improve the driving sensitivity by forming a magnetic circuit for circulating the magnetism of the magnet in the lens holder, thereby strengthening the magnetic field passing through the winding coil.

The present invention for this purpose, the first groove 122 and the second groove 124 and the first magnet 134 formed in the lens holder 110 facing the first magnet 134 and the second magnet 136, respectively ) And a third magnet 140 inserted into the first recess 122 so that the polarity thereof is opposite to the fourth magnet 142 inserted into the second recess 124 with the polarity opposite to the second magnet 136. As the optical pick-up actuator, a closed circuit of the magnetic flux passing through the winding coil 120 is formed by the third magnet 140 and the fourth magnet 142, so that the magnetic field passing through the winding coil 120 is strengthened and thus the lens holder. The driving sensitivity of the 110 is improved.

Description

Axis Type Optical Pickup Actuator with Magnetic Circuit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial type optical pickup actuator having a magnetic circuit. In particular, a magnetic circuit for circulating magnetism of a magnet is formed in a lens holder, thereby having a magnetic circuit for enhancing a magnetic field passing through a winding coil to improve driving sensitivity. An optical pickup actuator.

As shown in FIG. 1, a general shaft type optical pickup actuator is formed so as to penetrate a laser passage hole 13 up and down in the outer circumference of the disc-shaped body to fix the objective lens 12, and a plurality of winding coils ( 20 and the lens holder 10 to which the magnetic body 16 is fixed; The yoke 30 fixes the rotation shaft 38 coupled to the shaft hole 18 formed in the lens holder 10 at the center thereof, and fixes the magnets 34 and 36 to correspond to the winding coil 20 and the magnetic body 16. It consists of.

The rotary shaft 38 has a Teflon coating on the surface to reduce the friction coefficient, thereby reducing the loss of rotational force of the lens holder 10 and allowing the rotary shaft 38 to rotate or slide up and down about the rotary shaft 38. In addition, the negative resonance in the optical axis direction and the tracking direction generated in the lens holder 10 is damped by the friction generated between the shaft hole 18 and the rotation shaft 38.

In addition, two winding coils 20 and one magnetic body 16 are fixed to the side of the lens holder 10 at four divided positions of 90 °, and the winding coil 20 is disposed on the inner side of the yoke 30. And the magnets 34 polarized up and down and the magnets 36 magnetized to the left and right at positions corresponding to the magnetic body 16, respectively.

The magnets 36 divided by the polarity in the left and right directions are disposed at 180 ° intervals to generate electromagnetic force in the left and right directions in the winding coil 20 under the magnetic flux of the magnet 36, thereby forming the objective lens 12. When a tracking error occurred in the focus of the laser beam, the lens holder 10 was rotated in the tracking direction to correct the tracking error.

In addition, the magnet 34 divided up and down is also disposed at 180 ° to generate an electromagnetic force in the vertical direction in the winding coil 20 under the magnetic flux of the magnet 34, thereby forming the laser beam formed in the objective lens 12. When a focusing error occurs at the focus of the lens holder 10 is moved in the optical axis direction to correct the focusing error.

In addition, the four magnetic bodies 16 fixed to the rear lens holder 10 of the winding coil 20 are attracted to the magnetic flux of the magnets 34 and 36, thereby serving as a suspension that floats the lens holder 10 to a certain height. It was.

However, in the conventional actuator as described above, the magnetic flux emitted from the N poles of the magnets 34 and 36 is rapidly dispersed before reaching the winding coil 20, and then returns to the S poles of the magnets 34 and 36 again. In the coil 20, the driving force is not generated much larger than the magnetic field strength of the magnets 34 and 36.

Therefore, the conventional shaft type optical pickup actuator has a problem in that the magnetic flux passing through the magnets 34 and 36 is dispersed and thus the driving sensitivity of the lens holder 10 is weak.

The present invention has been made to improve the conventional problems, an object of the present invention is to form a magnetic circuit for circulating the magnetism of the magnet in the lens holder, to enhance the driving sensitivity by strengthening the magnetic field passing through the winding coil.

1 is an exploded perspective view of a general axial optical pickup actuator.

2 is an exploded perspective view of the optical pickup actuator according to an embodiment of the present invention.

3 is a plan view of the optical pickup actuator shown in FIG.

<Explanation of symbols for main parts of drawing>

110: lens holder 112: objective lens

116: magnetic material 118: shaft ball

120: winding coil 122: first groove

124: Second groove 130: York

132: axis of rotation 134: first magnet

136: second magnet 140: third magnet

142: fourth magnet

The present invention for achieving the above object, the lens holder is fixed to the objective lens and the axis of the optical axis is formed, a plurality of winding coils fixed to the side of the lens holder, and the rotating shaft coupled to the shaft hole is fixed A yoke and a first magnet fixed in an inner diameter of the yoke corresponding to one of the winding coils having polarized magnets up and down, and a second magnet fixed in an inner diameter of the yoke corresponding to the winding coils of the other fixed in left and right polarities An optical pickup actuator provided with a magnet; First and second grooves respectively formed in the lens holder facing the first magnet and the second magnet; A third magnet inserted into the first recess such that the polarity of the first magnet is opposite to the first magnet; And a fourth magnet inserted into the second recess such that the polarity of the second magnet is opposite to that of the second magnet.

The optical pick-up actuator has a magnetic flux from the north pole of the first magnet passing through the winding coil to the S pole of the third magnet, and then the magnetic flux from the north pole of the third magnet passes through the winding coil to the S pole of the first magnet. Since an incoming magnetic closure circuit is formed, it generates a driving force in a good focusing direction in the winding coil.

In addition, the magnetic closure circuit in which the magnetic flux from the N pole of the third magnet passes through the winding coil to the S pole of the fourth magnet, and the magnetic flux from the N pole of the fourth magnet passes through the winding coil and enters the S pole of the second magnet. Is formed, which generates a driving force in a good tracking direction in the winding coil.

Therefore, the optical pickup actuator of the present invention forms a magnetic circuit for circulating magnetism of the magnet in the lens holder, thereby enhancing the magnetic field passing through the winding coil to improve the driving sensitivity of the lens holder.

Hereinafter, preferred embodiments of the present invention will be described to facilitate implementation of the present invention.

First, an exploded perspective view of the axis type optical pickup actuator according to the present embodiment is shown in FIG. 2. As shown in this figure, the present embodiment is fixed to the objective lens 112, the lens holder 110, the shaft hole 118 in the optical axis direction is formed, and a plurality of winding coils fixed to the side of the lens holder 110 The yoke 130 is fixed to the 120, the rotating shaft 132 coupled to the shaft hole 118, and the polarizer is magnetized up and down to fix the inner diameter of the yoke 130 corresponding to the one-side winding coil 120 It is applied to an optical pickup actuator provided with one magnet 134 and a second magnet 136 fixed in the inner diameter of the yoke 130 corresponding to the other winding coil 120 by magnetizing from side to side.

These winding coils 20 are each fixed to four places of two to be eight. In addition, two adjacent and fixed winding coils 20 are wound in opposite directions, so that when the magnetic flux in the opposite direction passes through each of the winding coils 20, the electromagnetic force in the same direction is applied to each of the winding coils 20. To be generated.

On the other hand, the first magnet 134 is fixed to each one at a position of 180 °, and the second magnet 136 is also fixed to each one at a position of 180 ° to intersect the first magnet 134. In addition, the first groove 122 and the second groove 124 are formed in the lens holder 110 facing the first magnet 134 and the second magnet 136, respectively.

In addition, the third magnet 140 magnetized to face the first magnet 134 with the opposite polarity is inserted into the first recess 122. In addition, the fourth magnet 142 magnetized so as to face the second magnet 136 opposite to the second magnet 136 is inserted into the second groove 124.

In addition, the magnetic body 116 for floating the lens holder 110 by the magnetic force of the first magnet 134 and the second magnet 136 is fixed to the lens holder 110 of the portion where the winding coil 120 is fixed, respectively. do.

Hereinafter, the operation of the optical pickup actuator as described above.

For a description of this action, reference is made to FIG. 3, which shows a plane in the coupled state of the optical pickup actuator. In the optical pickup actuator of the present embodiment, the laser beam focused on the objective lens 112 through an optical system not shown is focused on the recording pit of the disk to reproduce the recording.

If a tracking error and focusing error occurs in the focus of the laser beam during the recording and reproduction, the signal processor applies a signal to the winding coil 120 to correct the tracking error and the focusing error.

Apart from this signal, the magnetic flux from the N pole of the first magnet 134 passes through the winding coil 120 to the S pole of the third magnet 140 and again, the magnetic flux from the N pole of the third magnet 140. The magnetic closing circuit is formed to enter the S pole of the first magnet 134 through the silver winding coil 120. Accordingly, the winding coil 120 corresponding to the first magnet 134 generates a driving force in a good focusing direction by the applied current.

In addition, the magnetic flux from the N pole of the third magnet 140 passes through the winding coil 120 to the S pole of the fourth magnet 142 and again, the magnetic flux from the N pole of the fourth magnet 142 is the winding coil ( A magnetic closure circuit is formed to pass through 120 and enter the S pole of the second magnet 136. Therefore, the winding coil 120 corresponding to the second magnet 136 generates a driving force in a good tracking direction by the applied current.

Accordingly, the lens holder 110 may drive well in the focusing direction and the tracking direction about the rotation axis 132 to correct the focusing error and the tracking error generated in the focus of the laser beam.

Here, the negative resonance generated in the lens holder 110 is reduced by the friction of the shaft hole 118 in contact with the rotating shaft 132.

As described in the above embodiments, the present invention includes a first groove 122 and a second groove 124 formed in the lens holder 110 facing the first magnet 134 and the second magnet 136, respectively. 4, the third magnet 140 inserted into the first recess 122 to face the first magnet 134 and the second magnet 124 inserted into the second recess 124 to face the second magnet 136. As the optical pickup actuator including the magnet 142, the closed circuit of the magnetic flux passing through the winding coil 120 is formed by the third magnet 140 and the fourth magnet 142, and thus passes through the winding coil 120. The magnetic field is enhanced to improve driving sensitivity of the lens holder 110.

Claims (1)

A lens holder 110 having an objective lens 112 fixed therein and having an axis hole 118 in the optical axis direction, a plurality of winding coils 120 fixed to a side of the lens holder 110, and the shaft hole 118. The yoke 130 is coupled to the rotating shaft 132 is fixed, the first magnet 134 is fixed to the inner diameter of the yoke 130 corresponding to the winding coil 120 is magnetized up and down the polarity and polarity, An optical pickup actuator having a second magnet (136) magnetized to the left and right and fixed to an inner diameter of the yoke (130) corresponding to the winding coil (120) on the other side; First and second grooves 122 and 124 formed in the lens holder 110 facing the first magnet 134 and the second magnet 136, respectively; A third magnet 140 inserted into the first recess 122 so that the polarity of the first magnet 134 is opposed; And And a fourth magnet (142) inserted into the second recess (124) such that the polarity of the second magnet (136) is opposite to the second magnet (136).