KR100220510B1 - Super thin type optical pick up actuator - Google Patents

Abstract

In particular, the present invention relates to an ultra-thin optical pickup actuator, and more particularly, to an ultra-thin optical pickup actuator that includes a focusing adjustment coil 50, a tracking adjustment coil 60, a focusing lens 104, An objective lens holder 100 having a thin plate-like shape and having recesses 105 through which holes 102 are respectively passed and in which a coil PCB 70 is placed; A moving shaft 120 fitted in the guide hole 72 of the coil cover 70 and the upper and lower moving holes 106 of the groove 105; A thin plate shaped yoke plate 130 having a fitting groove 132 in which the bottom end of the moving shaft 120 is fitted and having a first fixing groove 136 and a second fixing groove 138; A focusing magnet 140 installed in the first fixing groove 136; The present invention relates to an ultra-thin optical pick-up actuator, and more particularly, to an ultra-thin optical pick-up actuator capable of forming an ultra-thin and miniaturized optical pickup actuator by providing an ultra-thin optical pickup actuator constituted by a tracking magnet installed in a second fixing groove.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an ultra-thin optical pick-

In particular, the present invention relates to an ultra-thin optical pick-up actuator, in particular, an objective lens holder in which an objective lens, a focusing adjusting coil, a tracking adjusting coil, and a coil cover are respectively provided as a thin plate, The optical pick-up actuator can be configured as an ultrathin and ultra-small type by assembling the objective lens holder in the focusing and tracking adjustment directions about the moving axis by assembling the moving plate with a thin plate-shaped yoke plate on which the tracking magnet is mounted. The present invention relates to an ultra-thin optical pickup actuator.

In general, the optical pickup actuator is installed at the lower portion of the disc, which is an optical recording medium of various optical disc players such as a mini disc player (MDP), a compact disc player (C), and a laser disc player (LDP) A laser beam is incident on a pit recorded on a disk surface at a detected track position, the reflected light is detected through an optical system, the detected reflected light is converted into a signal, and the recorded content of the disk .

FIG. 1 is an exploded perspective view of a general wire type optical pickup actuator, and FIG. 2 is a perspective view of the coupled state of FIG. 1, wherein a conventional optical pickup actuator will be described with reference to the accompanying drawings.

The conventional optical pickup actuator structure includes a yoke plate 20 having a laser passage hole 1 formed at a lower portion of an actuator and a yoke plate 20 having a " A fixed yoke 23 spaced apart from the outer yoke 22 by a predetermined distance and formed on the outer side in the longitudinal direction of the yoke plate 20 and an outer yoke 22 An objective lens 25 which is provided above the laser passage hole 1 of the yoke plate 20 and focuses the laser beam on the pit surface of the disk, An objective lens holder 26 having a rectangular parallelepiped shape so that the objective lens 25 is mounted on the objective lens holder 26 and a focusing adjusting coil 27 provided on the circumferential surface of the objective lens holder 26 for controlling the objective lens 25 to operate in the optical axis direction And on the outer surface of the focusing adjusting coil 27, which is the both side surfaces of the objective lens holder 26 A tracking adjusting coil 28 which is provided so as to control the objective lens 25 to be operated in the radial direction and a suspension which attenuates the vibration generated in the objective lens holder 26 by signals input and output from the servo system A suspension coil 31 attached to the outside of the holder gel 30 and receiving the input and output signals of the servo system and a suspension coil 31 mounted on both sides of the objective lens holder 26, And a coil PCB 32 for electrically connecting the adjusting coil 27 and the tracking adjusting coil 28 to the suspension wire 29.

On the other hand, a focusing adjustment coil 27 and a tracking adjustment coil 28 are provided on the center of gravity of the objective lens holder 26, and the focusing adjustment coil 27 and the tracking adjustment coil 28 are provided with permanent magnets 24 The objective lens holder 26 is sufficiently operated in the focusing and tracking adjustment directions.

The operation of the general wire type optical pick-up actuator thus constructed will be described below.

As shown in Figs. 1 and 2, a photo detector on the optical system detects the focusing and tracking state of the laser beam focused on the recording pit of the disk. When the focusing and tracking state are detected, it is necessary to calibrate the optical system to transmit an electrical signal to the suspension PCB 31 in the servo system.

Next, when an electric signal transmitted to the suspension PCB 31 is transmitted to the coil PCB 32 through the suspension wire 29, the focusing control coil 27 and the tracking control coil 27, which are electrically connected to the coil PCB 32, 28).

When a current is applied to the focusing control coil 27 and the tracking control coil 28 from the coil PCB 32 as described above, the focusing control coil 27, the tracking control coil 28 and the outside of the yoke plate 20 The Lorentz driving force is generated between the permanent magnets 24 fixed to the yoke 22 and the objective lens holder 26 provided with the focusing adjusting coil 27 and the tracking adjusting coil 28 is driven by the driving force, Or in the tracking adjustment direction.

That is, when current is supplied through the four suspension wires 29 soldered and fixed to the back surface of the suspension PCB 31 from the servo system, the electric current passed through the suspension wire 29 is electrically connected to the two coil PCBs 32 Is applied to the focusing adjusting coil 27 and the tracking adjusting coil 28 which are connected to the focusing yoke 22 and the focusing yoke 22 by the current applied to the focusing adjusting coil 27 in the applied current The Lorentz driving force is generated between the permanent magnets 24 and the objective lens holder 26 is operated in the direction of the optical axis which is the focusing adjustment direction and also by the current applied to the tracking adjusting coil 28, A Lorentz driving force is generated, and the objective lens holder 26 operates in the radial direction as the tracking adjustment direction.

On the other hand, in the conventional optical pickup actuator, the objective lens holder 26 on which the objective lens 25 is placed is formed in the shape of a rectangular parallelepiped, and on the outer peripheral surface thereof, a focusing adjustment coil 27, a tracking adjustment coil 28, And a suspension wire 29 connected to the suspension lens 31 and penetrating the holder gel 30 is connected to the coil cover 32 to support the objective lens holder 26 , The number of optical pickup actuator components is large and its configuration is complicated. Thus, there is a problem that the overall size and thickness of the optical pickup actuator are increased when the optical pickup actuator is used in a CD and an LFD.

SUMMARY OF THE INVENTION The present invention has been made in order to solve such conventional problems, and it is an object of the present invention to construct an optical pickup actuator with ultra thin and ultra small size.

According to an aspect of the present invention, there is provided an optical pickup actuator including a focusing adjusting coil and a tracking adjusting coil for receiving a current through a coil PCB and an objective lens for focusing the laser beam, An objective lens holder having a thin plate-like shape in which a tracking mounting hole in which a focusing mounting hole and a tracking adjusting coil are symmetrically arranged and a lens mounting hole in which an objective lens is mounted are respectively penetrated, ; A moving shaft which is inserted in the upper and lower moving holes passing through the center of the groove and penetrates the center of the coil PCB and guides the movement and rotation of the objective lens holder; A first fixing groove is formed in a lower portion corresponding to the focusing installation hole and a second fixing groove is formed in a lower portion of the position where the tracking adjusting coil is horizontal, An oak plate; A focusing magnet installed in the first fixing groove and generating a magnetic force on the focusing adjusting coil; And a tracking magnet provided in the second fixing groove and generating a magnetic force in the tracking adjusting coil.

1 is an exploded perspective view of a general wire type optical pickup actuator,

Fig. 2 is a perspective view of the coupled state of Fig. 1,

3 is an exploded perspective view of an ultra-thin optical pickup actuator according to the present invention,

Fig. 4 is a perspective view of the coupled state of Fig. 3,

5 is a side view of the coupled state of Fig. 3,

6 is an operating state perspective view of the present invention,

FIGS. 7A and 7B are views showing the focusing operation of the present invention in detail,

FIG. 7A is a perspective view showing a state in which a driving force in the focusing adjustment direction is generated in the focusing coil by the current of the focusing adjusting coil and the magnetic force of the focusing magnet,

7B is a plan view of 7a,

FIGS. 8A and 8B are views showing in detail the tracking action of the present invention,

8A is a perspective view showing a state in which a driving force in a tracking adjusting direction is generated in the tracking adjusting coil by the current of the tracking adjusting coil and the magnetic force of the tracking magnet,

8B is a plan view of 8a.

DESCRIPTION OF THE REFERENCE NUMERALS

50: focusing adjusting coil 60: tracking adjusting coil

70: Coil FPC 80: Objective lens

90: Flexible PCB 100: Objective lens holder

102: Lens insertion hole 104: Focusing installation hole

106: Up and down moving balls 107: Tracking mounting balls

110: spring 120: moving shaft

130: yoke plate 132: fitting groove

134: latching jaw 136: first fixing groove

138: second fixing groove 140: focusing magnet

150: Tracking magnet

3 is an exploded perspective view of the ultra-thin optical pickup actuator according to the present invention, FIG. 4 is a perspective view of the combined state of FIG. 3, FIG. 5 is a side view of the combined state of FIG. 3, FIGS. 7A and 7B are views showing a focusing operation of the present invention. FIG. 7A shows a state in which a driving force in the focusing direction is generated in the focusing coil by the current of the focusing coil and the magnetic force of the focusing magnet. 8A and 8B are diagrams showing a tracking operation of the present invention. FIG. 8A is a graph showing the tracking operation of the tracking adjusting coil by the current of the tracking adjusting coil and the magnetic force of the tracking magnet. FIG. FIG. 8B is a plan view showing a state in which a driving force in an adjusting direction is generated, and FIG. 8B is a plan view of FIG. 8A, and the present invention will be described in detail with reference to the accompanying drawings.

The ultra-thin optical pickup actuator of the present invention includes an optical pick-up actuator 50 having a focusing adjustment coil 50 and a tracking adjustment coil 60 that receive a current through a coil PCB 70 and an objective lens 80 for focusing a laser beam, An objective lens holder 100 having a thin plate shape and provided with a groove 105 to which a coil cover 70 is placed at a central portion to be adhered and fixed, a guide hole 72 penetrating a central portion of the coil cover 70, A moving shaft 120 which is inserted in the upper and lower moving holes 106 passing through the center of the groove 105 and guides the upward and downward movement and rotation of the objective lens holder 100, A thin plate-like yoke plate 130 formed with a fitting groove 132 into which a first fixing groove 136 and a second fixing groove 138 are formed, A focusing magnet 140 for generating a magnetic force on the focusing adjusting coil 50, It consists of a king-adjustment coil 60, the tracking magnet 150, which generates a magnetic force on.

The objective lens holder 100 is provided with a focus setting hole 104 in which a focusing adjusting coil 50 is provided and a tracking setting hole 107 in which the tracking adjusting coil 60 is symmetrically arranged, And lens-receiving holes 102 to be installed are respectively formed.

The positions of the first fixing groove 136 and the second fixing groove 138 formed on the yoke plate 130 are adjusted such that the first fixing groove 136 is aligned with the focusing mounting hole 104 of the objective lens holder 100 And the second fixing groove 138 is formed at the lower portion of the position where the two tracking adjusting coils 60 are horizontal.

The flexible PCB 90, which is soldered to the coil PCB 70 and supplies current, is configured to support the operation of the objective lens holder 100 and to perform a damping function.

Both ends are fixed to the fixing jaw 109 and the engaging jaw 134 between the fixing jaw 109 formed on the bottom surface of the objective lens holder 100 and the jaw 134 formed on the upper surface of the yoke plate 130 And a spring 110 for absorbing vibration when the objective lens holder 100 is rotated and moved up and down.

The tracking adjusting coil 60 is formed in a semicircular shape as shown in the accompanying drawings, and the focusing magnet 140 and the tracking magnet 150 are configured to have a larger width from the inside to the outside.

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

First, the assembly process of the ultra-thin optical pickup actuator of the present invention will be described.

The objective lens 80 formed on the objective lens holder 100 and the focusing adjustment coil 50 and the tracking adjustment coil 60 are provided on the lens installation hole 102, the focusing mounting hole 104, the tracking mounting hole 107, And a focusing adjustment coil 50 and a tracking adjusting coil 50 are mounted on the groove 105 formed in the center of the objective lens holder 100 and recessed at a predetermined depth, 60 and a coil cover 70 electrically connected to the coil cover 70. The coil cover 70 is adhered and fixed with a U-Bond bond.

The contact of the flexible PCB 90 is soldered and fixed to the contact of the coil PCB 70 so that current is supplied to the coil PCB 70. The flexible PCB 90 is used to pull up the objective lens holder 100, Configure it to perform the role.

The guide pin 72 penetrating the center of the coil cover 70 and the upper and lower moving holes 106 penetrating the central portion of the groove 105 of the objective lens holder 100 Next, the bottom end of the moving shaft 120 is press-fitted into the fitting groove 132 formed in the center of the yoke plate 130.

In the process of assembling the objective lens holder 100 and the yoke plate 130 together with the moving shaft 120, the upper end of the spring 110 is fitted to the objective lens holder 120 by sandwiching the spring 110 on the moving shaft 120. [ The objective lens holder 100 and the yoke plate 130 are fixed to the fixing jaw 109 formed on the bottom surface of the yoke plate 100 and the lower end of the spring 110 is fixed to the jaw 134 of the yoke plate 130, The objective lens holder 100 is assembled in a state where the objective lens holder 100 is doubly damped by the flexible PCB 90 and the spring 110. In this case,

The focusing magnet 140 and the tracking magnet 150 are fixedly attached to the first fixing groove 136 and the second fixing groove 138 of the yoke plate 130 to complete the assembly of the present invention.

The operation of the present invention will now be described.

First, when a user presses a play button or the like to send an operation signal, the current is supplied to the flexible PCB 90, which is transmitted to the coil PCB 70 connected to the flexible PCB 90 And is transmitted to the focusing adjusting coil 50 and the tracking adjusting coil 60 which are connected to the contacts of the coil PCB 70.

In the state where current is transmitted to each focusing adjusting coil 50 and the tracking adjusting coil 60 provided in the objective lens holder 100 as described above, the focusing magnet 140 and the tracking magnets 140 provided on the yoke plate 130, A magnetic force is applied to the focusing adjusting coil 50 and the tracking adjusting coil 60 through which the current flows by the magnet 150. [

The Lorentz driving force is generated in the focusing adjusting coil 50 and the tracking adjusting coil 60 and the objective lens holder 100 is driven by the Lorentz driving force through the upper and lower moving holes 106 and the guide holes 72 The objective lens 80 moves or rotates in the upward or downward direction along the moving shaft 120 fixed to the yoke plate 130 so that the objective lens 80 accurately focuses the laser beam on the pit surface (not shown) And the laser beam reflected through the disk is signaled through a photodetector.

When correction is required as a result of detection of the focusing and tracking states, Lorentz driving force is applied to the focusing adjusting coil 50 and the tracking adjusting coil 60 to adjust the position of the objective lens holder 100 again, It is necessary to accurately read the necessary signals interposed in the disc.

The focusing operation and the tracking operation of the present invention will be described in detail with reference to the accompanying drawings.

First, the focusing operation of the present invention will be described with reference to FIG. 6 and FIGS. 7A and 7B.

7A and 7B, when the current passed from the flexible PCB 90 through the coil PCB 70 to the focusing adjusting coil 50 flows in the clockwise direction as shown in FIGS. 7A and 7B, The magnet 140 generates a magnetic force in the focusing adjusting coil 50. [

That is, a vertical magnetic force B1 is generated from the focusing magnet 140 at a portion of the focusing adjusting coil 50 through which the I1 current flows, and a driving force of F1 to flow horizontally outward in accordance with Lorentz's law is generated.

A vertical magnetic force B3 is generated from the focusing magnet 140 at a portion of the focusing adjusting coil 50 through which the I3 current flows and the driving force of F3 to flow horizontally inward in the direction opposite to F1 in accordance with Lorenz's law .

On the other hand, depending on the general property of the magnetic force generated in the arc direction from the N pole to the S pole at the edge portion of the magnet, a portion of the focusing adjusting coil 50 through which the I2 current flows as shown in Fig. B2 is applied from the focusing magnet 140 and a driving force of F2 to flow vertically upward is generated at a portion of the focusing adjusting coil 50 through which the I2 current flows according to the Lorentz law.

In addition, according to the general characteristics of the magnetic force generated at the corner portion of the magnet, a horizontal magnetic force B4 is applied from the focusing magnet 140 to a portion of the focusing adjusting coil 50 through which the I4 current flows, The driving force of F4 to flow vertically upward is generated.

On the other hand, although the magnetic force of the focusing magnet 140 applied to the portion of the focusing adjusting coil 50 through which the I1 and I3 currents flow is greatest, the driving forces F1 and F3 generated at this portion cancel each other, 50 are moved by a driving force generated at a portion of the focusing adjusting coil 50 through which currents I2 and I4 flow.

That is, the focusing adjustment coil 50 is subjected to the upward driving force by the driving force of the vertical upward F2 and F4 generated in the portion of the focusing adjusting coil 50 through which the currents I2 and I4 flow, The objective lens holder 100 in which the lens holders 50 and 50 are fixed is also subjected to the upward driving force.

When the direction of the current transmitted to the focusing adjusting coil 50 is changed in the counterclockwise direction, the objective lens holder 100, in which the focusing adjusting coil 50 is fixed according to the Lorentz law as described above, .

Thus, the objective lens holder 100 is moved in the upward and downward directions along the moving shaft 120 fixed to the yoke plate 130 by the Lorentz driving force in the upward and downward directions as described above.

On the other hand, the magnetic force B3 applied to the portion of the focusing adjusting coil 50 through which the I3 current flows is larger than the magnetic force B1 applied to the portion of the focusing adjusting coil 50 through which the I1 current flows So that F3 is slightly larger than F1. However, the driving force for F3-F1 is directed to the moving shaft 120, which is the central axis, to prevent the objective lens holder 100 from swinging.

Next, the tracking operation of the present invention will be described with reference to Fig. 6 and Figs. 8A and 8B.

The current transmitted to the two tracking adjusting coils 60 from the flexible PCB 90 through the coil PCB 70 flows in one direction as shown in FIGS. 8A and 8B, The tracking magnet 150 installed generates a magnetic force on the tracking adjusting coil 60. [

At this time, the portion of the tracking adjustment coil 60 through which the currents I2 and I4 flow is farther away from the tracking magnet 150 than the portion of the tracking adjustment coil 60 through which the currents I1 and I3 flow, The magnetic force of the tracking magnet 150 applied to the portion of the coil 60 becomes much smaller than the magnetic force applied to the portion of the tracking adjustment coil 60 through which the currents I1 and I3 flow, I1 and I3 move according to the driving force generated by the magnetic force applied to the current flowing portion.

That is, the magnetic force B1 in the vertical direction is generated from the tracking magnet 150 at the portion of the tracking adjusting coil 60 through which the I1 current flows, and the driving force of F1 to flow horizontally in the left direction in the drawing is generated in accordance with Lorenz's law .

A magnetic force B3 in the vertical direction is generated from the tracking magnet 150 at a portion of the tracking adjusting coil 60 through which the I3 current flows, and a driving force of F3 to flow horizontally in the leftward direction according to Lorenz's law is generated.

Therefore, the tracking adjustment coil 60 is subjected to the driving force in the left direction by the driving forces F1 and F3 in the left direction generated in the portion of the tracking adjusting coil 60 through which the currents I1 and I3 flow, The objective lens holder 100 is also subjected to the driving force in the left direction.

When the direction of the current transmitted to the tracking adjusting coil 60 is changed in the opposite direction, the objective lens holder 100 in which the tracking adjusting coil 60 is fixed in accordance with the Lorentz law as described above is subjected to the driving force in the right direction do.

Thus, the objective lens holder 100 is rotated in the left and right directions around the moving shaft 120 fixed to the yoke plate 130 by the driving force in the left and right directions as described above, .

As described above, according to the present invention, focusing or tracking adjustment is performed as the objective lens holder 100 rotates in the upward and downward directions and the left and right directions about the moving axis 120.

When the objective lens holder 100 is moved upward and downward and the objective lens holder 100 is moved up and down with respect to the objective lens holder 100 and the stoppers 134 of the objective lens holder 100 and the jaws 134 of the yoke plate 130, And the flexible PCB 90 fixed to the coil cover 70 of the objective lens holder 100 by soldering so that the objective lens holder 100 is damped and stably operated.

As described above, according to the ultrathin optical pickup actuator of the present invention, the objective lens holder 100 in which the objective lens 80, the focusing adjusting coil 50, the tracking adjusting coil 60, and the coil cover 70 are installed, The objective lens holder 100 is assembled to the thin plate shaped yoke plate 130 on which the thin focusing magnet 140 and the tracking magnet 150 are mounted with the moving shaft 120 And the objective lens holder 100 is adjusted in the focusing and tracking adjustment directions with respect to the moving shaft 120 so that the optical pickup actuator can be configured to be ultra thin and miniaturized.

Claims (5)

An optical pick-up actuator comprising a focusing adjustment coil (50) and a tracking adjustment coil (60) supplied with current through a coil PCB (70), and an objective lens (80) A tracking mounting hole 107 in which the tracking adjusting coil 60 is provided so as to be symmetrical to each other and a lens mounting hole 107 in which the objective lens 80 is installed, An objective lens holder 100 in the form of a thin plate-like object, through which the balls 102 pass, a groove 105 in which the coil PCB 70 is positioned and adhered to the center, is formed; A guide hole 72 penetrating a central portion of the coil cover 70 and an upper and a lower moving hole 106 penetrating the center of the groove 105 to move the objective lens holder 100 upward, A movement shaft 120 for guiding rotation; A fitting groove 132 in which a bottom end of the moving shaft 120 is fitted is formed and a first fixing groove 136 is formed in a lower portion corresponding to the focusing mounting hole 104. The tracking adjusting coil 60 A thin plate-shaped yoke plate 130 having a second fixing groove 138 at a lower portion of the horizontal position; A focusing magnet (140) installed in the first fixing groove (136) and generating a magnetic force on the focusing adjusting coil (50); A tracking magnet (150) installed in the second fixing groove (138) and generating a magnetic force on the tracking adjusting coil (60); And an actuator for driving the optical pick-up actuator. The flexible lens unit according to claim 1, further comprising a flexible PCB (90) configured to be soldered to the coil cover (70) to supply current, and to support the operation of the objective lens holder (100) An ultra-thin optical pick-up actuator. The objective lens holder according to claim 1, further comprising a fixing jaw (109) formed on a bottom surface of the objective lens holder (100) and a fixing jaw (134) formed on an upper surface of the yoke plate (130) And a spring (110) for absorbing vibration when moving up, down, and rotating. (delete) The ultra-thin optical pickup actuator according to claim 1, wherein the focusing magnet (140) and the tracking magnet (150) have a larger width from the inside to the outside.