KR100403083B1 - Optical pickup actuator having tilt correction - Google Patents

Abstract

The present invention relates to an optical pickup actuator capable of tilting servo, and an optical pickup actuator capable of tilting driving according to the present invention includes a lens holder having an objective lens mounted thereon, and a magnetic holder for operating the lens holder. An optical pickup actuator comprising a coil and a magnet installed in a space of a circuit, and a wire suspension for supplying current to each of the coils and supporting a lens holder.

One of the tracking and focusing coils installed in the magnetic circuit space is separated for tilting driving, and four wire suspensions are provided to supply current to the coils, and one of the four wire suspensions is the other three wires. It is characterized by being grounded in common to the suspension.

According to the present invention, for the optical pickup actuator capable of tilting driving, four wire suspensions, in which a separately installed tracking coil and one wire suspension are used as a common ground terminal without adding wire suspension, yoke, and magnet, are used. The servo of three degrees of freedom of the actuator is enabled.

Description

Optical pick-up actuator with tilting drive {OPTICAL PICKUP ACTUATOR HAVING TILT CORRECTION}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an optical pickup actuator capable of tilting driving in which the focusing coil is radially divided and the driving current in the focus, tracking, and tilt directions can be supplied by four wire suspensions.

Optical pickup is a key component that enters a driver that reads and writes CD-R, CD-RW, DVD, etc., and uses light to discriminate optical differences on the surface of the recording material to read information or generate optical differences. Record the operation.

In general, the recording material is assumed to have a flat surface as a disc-shaped object. However, in a practical situation, the recording surface of the recording material is a track position where information is recorded due to manufacturing errors and deformations, vibration due to rotation, and errors in the optical pickup itself. Is changed relative to the optical pickup, and is compensated by a special mechanism that drives the objective lens OL closest to the recording medium by an electrical signal to compensate for this.

Such a mechanism is called an actuator and is generally composed of a coil and a magnet to move the objective lens by the current flowing through the coil and the electromagnetic force between the magnets.

At this time, as shown in (a), (b) and (c) of FIG. 1, the objective lens 1 of the actuator follows the recording surface 2a of the recording body 2 by a servo so that a track error, a tilt error, This compensates for the focusing error. (A), (b) and (c) of FIG. 1 are diagrams showing compensation of a tracking error, a focusing error, and a tilting error, respectively. However, currently used optical pickup actuators mainly compensate for tracking errors and focusing errors.

The configuration of a conventional optical pickup actuator is briefly described as follows.

2 (a) and 2 (b) are a perspective view and a side view of a conventional optical pickup actuator. As shown therein, the objective lens 11 is mounted at the center and the tracking coils 14a to 14d and the focusing coil are circumferentially disposed. Lens holder 12 provided with (13), yoke 15 of ferromagnetic material protruding from the frame 19 to the left and right of the lens holder 12, and the magnet 16 fixed to the yoke 15 ), A damper holder 17 installed on the frame 19 with the magnet on one side of the lens holder 12, and a lens holder 12 and a damper holder to lift the lens holder 12. It consists of a plurality of wire suspensions 18 connected to the upper and lower portions of 17.

The operation of the conventional optical pickup actuator configured as described above will be described with reference to FIGS. 2 to 5.

Referring to (a) and (b) of FIG. 2, the objective lens 11 serves to condense a light beam incident from a light source on a recording medium, and to follow the disk in the tracking and focusing direction of the lens holder 12. It is mounted in the annular hole formed in the center part. The focusing coil 13 is wound around the entire side of the lens holder 12, and the tracking coils 14a to 14d are divided and bonded to the left and right winding surfaces of the focusing coil 13.

The magnet 16 is bonded to the yoke 15 of the ferromagnetic material protruding from the frame 19 so as to face the tracking coils 14a to 14d and the focusing coil 13, respectively, and the tracking coils 14a to 14d and the focusing coil. Generates magnetic flux that bridges (13).

In addition, a damper holder 17 is provided at one side of the lens holder 12, and the plurality of wire suspensions 18 are fixed substrates (not shown) and the damper holders installed at left and right side centers of the lens holder 12. Two parallel to each other between the main substrate (not shown) fixed to the (17) is provided to lift the lens holder 12 and to support it elastically, and the current to the tracking coils (14a ~ 14d) and the focusing coil (13) To supply.

The four wire suspensions 18 supply current to the tracking coils 14a to 14d and the focusing coils 13 to operate the lens holders 12 in the tracking and focusing directions according to the current directions. As shown in (a) and (b) of 3, the tracking coils 14a to 14d are wound in a predetermined direction to generate magnetic flux in a predetermined direction when current flows, and the magnetic flux is fixed to the left and right sides. Repulsive force and repulsive force are generated by the magnet 16 and the electromagnetic force to move the lens holder 12 in the tracking direction, thereby compensating for tracking errors due to the current control of the tracking servo. By the Lorentz force in the horizontal direction, the objective lens 11 is driven in the horizontal direction on the disk surface.

As shown in (a) and (b) of FIG. 4, the focusing coil 13 is wound in a vertical direction differently from the tracking coils 14a to 14d so that the direction of the magnetic flux occurs in the up and down directions when current flows. The magnetic flux acts electromagnetically with the magnetic flux of the fixed magnets 16 to generate a force in the vertical direction in the coil 13. As a result, the lens holder 12 moves in the up and down directions, and a focusing servo is performed to compensate for the focusing error through the movement. By the Lorentz force in the vertical direction, the objective lens 11 is driven in the direction perpendicular to the disk plane.

Referring to FIG. 5, when the current supply circuit is configured, two wire suspensions 18 are connected to both ends of the tracking coils 14 (14a to 14d), respectively, through which the positive (+) and negative (-) power sources Vcc1 are connected. ) Is supplied, and the other two wire suspensions 18 are connected to both ends of the focusing coil 13, and a positive (+) and a negative (-) power supply (Vcc2) is supplied thereto.

However, in the structure of the optical pickup actuator described above, only the objective lens 11 can be driven in the horizontal direction and the vertical direction, and the tilt servo for compensating the tilting error is impossible. If the disc is tilted, the optical axis of the light beam incident on the disc from the objective lens has an arbitrary inclination angle that is not perpendicular to the plane of the disc. In this case, the reflected light beam reflected from the disc cannot accurately reproduce data. .

To this end, an example of an optical pickup actuator structure capable of a conventional tilting drive is shown in FIGS. 6 and 7.

6 and 7, the focusing coils 23 are wound around the entire side of the lens holder 22 in which the objective lens 21 is mounted in the center, and two on the left and right sides of the focusing coil 23. On the upper and lower sides, one tracking coil 24a to 24f is provided. The yoke 25a-25d and the magnet 26 are provided in each direction which opposes the said focusing coil 23 and the tracking coils 24a-24f, respectively. Reference numeral 27 is a damper holder, and 28 is a wire suspension.

In this way, the tracking coils 24a to 24f and the magnets 26 are added to enable the tilting drive, and the yokes 25a to 25d are additionally formed to support the magnets 26 and make the magnetic flux path. The upper and lower tracking coils 24e and 24f are wound so as to generate magnetic fluxes in opposite directions with respect to the opposing magnets 26, or the magnets are fixed in opposite directions. Therefore, when current flows in the tracking coils 24e and 24f, the two tracking coils 24e and 24f generate forces in opposite directions, and the lens holder 21 rotates by the magnetic flux. For this tilting drive, two of the four wire suspensions are added to supply current to the six wire suspensions.

As shown in FIG. 7, the tilting driving in the above structure is performed by supplying currents in opposite directions to one tracking coil 24e and the other tracking coil 24f of the lens holder 22, and those of FIG. As it is tilted driving, when the current is supplied to the contrary, it is tilted as shown in (b) of FIG.

In order to enable such a tilting drive, a circuit configuration as shown in FIG. 8 is required. This supplies a positive (+) and a negative (-) power supply (Va) to the focusing coil (L1) through two wire suspensions (W1 and W2), and two wire suspensions (W5) to the first tracking coil (L2). , W6) to supply the positive (+) and negative (-) power supply (Vb), and connect the two wire suspensions (W3, W4) to the second tracking coil (L3) to positive (+) and negative The negative power supply Vc is supplied. That is, it has six wire suspensions W1 to W6 and connects three power supplies Va, Vb, and Vc to provide current signals applied to the first and second tracking coils L2, L3 and the focusing coil L1. Control is performed by a tracking servo, a focusing servo, and a tilt servo.

However, in order to make an optical pickup actuator capable of tilting driving, a coil, a magnet, a yoke, etc. need to be added, thereby increasing the weight of the lens holder. This deteriorates the dynamic characteristics of the actuator when the lens holder is operated, resulting in a price increase.

In addition, in order to drive an additional coil, two wire suspensions for supplying current must be further provided, which is a structure in which the lens holder is supported by six wire suspensions W1 to W6. Suspensions W1 to W6 may generate asymmetrical movements during tilt servo, and the connection and assembly thereof are difficult.

The present invention has been made to solve the above-mentioned conventional problems, while dividing the focusing coil that generates the magnetic flux in the vertical direction, while changing the current supply method has four conventional wire suspensions without installing additional coils and magnets It is an object of the present invention to provide an optical pickup actuator capable of a tilting drive that enables a tilting drive.

1 (a) (b) (c) are diagrams showing tracking errors, focusing errors, and tilting errors.

Figure 2 (a) (b) is a perspective view of a conventional optical pickup actuator.

3 (a) and 3 (b) show a tracking state of a conventional optical pickup actuator.

4 (a) and 4 (b) show a focusing state of a conventional optical pickup actuator.

5 is a circuit configuration diagram of a tracking and focusing coil configuration of a conventional optical pickup actuator and a current supply thereto.

Figure 6 is a perspective view of a conventional optical pickup actuator capable of tilting drive.

Figure 7 (a) (b) is a tilting drive state diagram of the conventional actuator of Figure 6;

8 is a coil configuration of a conventional optical pickup actuator capable of tilting drive.

9 is a block diagram of an optical pickup actuator capable of tilting driving in accordance with the present invention.

10 is a coil magnetic flux direction capable of tilting driving in the optical pickup actuator of the present invention and an operation state thereof.

11 is a circuit diagram of an optical pickup actuator capable of tilting driving according to the present invention.

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

11,21,31 ... Objective lens 12,22,32 ... Lens holder

13,23,33a, 33b ... focusing coil

14a ~ 14d, 24a ~ 24f, 34a ~ 34d ... tracking coil

15,25a ~ 25d, 35 ... York 16,26,36 ... Magnet

17,27,37 ... damper holder 18,28,38 ... wire suspension

In order to achieve the above object, the optical pickup actuator capable of tilting drive according to the present invention,

An optical pickup actuator comprising a lens holder on which an objective lens is mounted, a coil and a magnet installed in a space of a magnetic circuit to operate the lens holder, and a wire suspension that supplies current to each of the coils and supports the lens holder. ,

One of the tracking and focusing coils installed in the magnetic circuit space is separated for tilting driving, and four wire suspensions are provided to supply current to the coils, and one of the four wire suspensions is the other three wires. It is characterized by being grounded in common to the suspension.

Hereinafter, the present invention will be described with reference to the accompanying drawings.

9 is a configuration diagram of an optical pickup actuator capable of tilting driving according to the present invention, FIG. 10 is a coil magnetic flux direction capable of tilting driving and an operating state diagram of the optical pickup actuator of the present invention, and FIG. It is a circuit block diagram of the optical pickup actuator which can be tilted.

9 and 10, an objective lens 31 is mounted, and first and second focusing coils 33a and 33b are wound therein and winding surfaces of the first and second focusing coils 33a and 33b. A lens holder 32 movable with tracking coils 34a to 34d attached thereto, and a yoke 35 protruding from the frame to the left and right sides of the lens holder 32 and a magnet 36 fixed to each of the yokes. And, the damper holder 37 provided on one side of the lens holder 32, one end is connected to the center of the left and right surface of the lens holder 32, the other end through the damper holder 37, the main substrate (not shown) Four wire suspensions 38 connected to the first and second focusing coils 33a and 33b and the tracking coils 34a to 34d to supply current.

As shown in FIG. 11, three wire suspensions 38a, 38b, 38c of the four wire suspensions 38 have one end connected to the first and second focusing coils 33a, 33b and the tracking coil 34. The other end is connected to the plus (+) end of each of the power supplies Va, Vb, and Vc, and the other wire suspension 38d is connected to the first and second focusing coils 33a and 33b and the tracking coil ( Connect 34a ~ 34d) to common ground terminal (GND).

The optical pickup actuator capable of tilting driving according to the present invention configured as described above will be described with reference to the accompanying drawings.

9 and 10, the objective lens 31 collects a light beam incident from a light source on a disk. The objective lens 31 is fitted in the annular hole formed in the center of the lens holder 32.

The first and second focusing coils 33a and 33b are divided in the radial direction of the disk around the objective lens 31 and wound around the lens holder 32. One end of the first and second focusing coils 33a, 33b is supplied with current from two wire suspensions of four wire suspensions 38, and the other end is commonly connected to one grounded wire suspension, focusing servo and tilt Depending on the servo, two wire suspensions provide the same or different current signal direction and level.

Here, the first and second focusing coils 33a and 33b are provided as shown in FIG. 9 (b) for focusing and tilting the optical pickup actuator, and the first focusing coil 33a and the first At the center where the two focusing coils 33b are in contact, a space is provided for the laser beam to pass on the disk.

The tracking coils 34a to 34d are wound in a vertical direction so that the coil direction in the magnetic space becomes a direction orthogonal to the first and second focusing coils 33a and 33b, so that the first and second focusing coils 33a, To 33b). The first and third tracking coils 34a and 34c are bonded to the first focusing coil 33a and the second and fourth tracking coils 34b and 34d are attached to the second focusing coil 33b.

The tracking coils 34a to 34d are supplied with a positive power supply Vc from one of the four wire suspensions 38 and the other end thereof is commonly connected to the wire suspension to which the focusing coils 33a and 33b are grounded. do.

The four wire suspensions 38 are installed between a fixed substrate (not shown) installed at the left and right centers of the lens holder 32 and a main substrate (not shown) fixed to the damper holder 37. Floating and elastically supporting the 32, the current signal is supplied to the focusing coils 33a, 33b and the tracking coils 34a, 34b, 34c, 34d.

The magnet 36 provided around the lens holder 32 is fixed to the yoke 35 so as to face the tracking coils 34a, 34b, 34c, and 34d and the focusing coils 33a and 33b. The magnetic flux generated from the magnets 36 facing the tracking coils 34a, 34b, 34c, 34d and the first and second focusing coils 33a, 33b is thus applied to the tracking coils 34a, 34b, 34c, 34d. The first and second focusing coils 33a and 33b are bridged.

The driving force in the focusing direction of the optical pickup actuator is the first and second focusing coils 33a and 33b in the magnetic space provided by the magnets 36 and the yoke 35 in the first and second focusing coils 33a and 33b. This signal is generated when a current signal having the same direction and level is applied. The objective lens 31 is moved in the vertical direction with respect to the disk surface by the Lorentz force in the focusing direction generated at this time.

The driving force in the tracking direction is generated when a current signal is supplied to the tracking coils 34a to 24d in which the magnetic flux in the magnetic space provided by the magnet 36 and the yoke 35 crosses. At this time, the objective lens 31 is moved in the radial direction of the disk by the Lorentz force in the radial direction.

The driving force in the tilt direction is different from each other in the first and second focusing coils 33a and 33b in the magnetic space provided by the magnet 36 and the yoke 35 as shown in (a) and (b) of FIG. 10. (Polarity) or when current signals having different levels are respectively applied. At this time, the objective lens 31 is moved at an angle inclined in the radial direction with respect to the disk surface by the Lorentz force in the tilt direction generated. In other words, the inner and outer peripheral portions of the objective lens 31 are inclined at different heights in the radial direction of the disk.

That is, when the currents applied to the first and second focusing coils 33a and 33b are supplied in different directions or levels differently for driving in the tilt direction, the first focusing coil 33a and the second focusing coil 33b are provided. The objective lens 31 is inclined at different heights on the disk surface by raising or lowering to these different heights.

On the other hand, the circuit configuration of the four wire suspension 38, the tracking coil and the focusing coil is 4 in the first and second focusing coils 33a, 33b and the tracking coils 34; 34a to 34d, as shown in FIG. Current is supplied by the two wire suspensions 38a, 38b, 38c, 38d, one end of the first and second focusing coils 33a, 33b and the tracking coils 34; 34a to 34d being connected to the three wire suspensions 38a. A current is supplied through 38b and 38c, and the other ends of the first and second focusing coils 33a and 33b and the tracking coils 34; 34a to 34d are connected to the ground terminal (d) by the remaining one wire suspension 38d. GND).

The four wire suspensions 38a to 38d, the first and second focusing coils 33a and 33b, and the tracking coils 34 and 34a to 34d thus not only move the objective lens 31 in the focusing and tracking directions, It also drives in the tilt direction.

As another embodiment of the present invention, although not shown, the tracking coil is installed separately for the tilting drive and the power is supplied to the four wire suspensions. The tracking coil provided in the space of the magnetic circuit for the tilting of the lens holder is provided. Separately installed, power is supplied from the two wire suspensions to the separated tracking coils and power is supplied to the focusing coils with the remaining one wire suspension. The remaining one wire suspension of the four wire suspensions provides a common grounding of the separated tracking coil and the focusing coil.

These tracking coils operate by receiving a pair of currents from each wire suspension in pairs around the lens holder, thereby enabling tilting driving of the lens holder while supporting the lens holder with four wire suspensions, In order to supply the current to the provided coils.

As described above, the optical pickup actuator capable of tilting driving according to the present invention can be driven in the tracking and focusing direction and the tilting direction without adding the yoke, the magnet and the wire suspension, and thus, from the recording medium as compared to the conventional optical pickup. Reading and writing information is stable and can improve overall performance.

In addition, even if the recording surface of the recording material changes relatively to the optical pickup due to manufacturing errors and deformations, vibrations due to rotation, and errors in the optical pickup itself, the possibility of recording information is increased, and at the same time, the existing actuator In addition to the six wire suspensions provided in the four wire suspensions, the tilting drive is possible, so that the assembly of the actuator is convenient and structurally stable.

Claims (2)

An optical pickup actuator comprising a lens holder on which an objective lens is mounted, a coil and a magnet installed in a space of a magnetic circuit to operate the lens holder, and a wire suspension that supplies current to each of the coils and supports the lens holder. , Any one of a tracking coil and a focusing coil installed in the magnetic circuit space is used as a tilting control coil, and four wire suspensions are provided to supply current to the coils, and one of the four wire suspensions is the other three. An optical pickup actuator, which is grounded in common to the wire suspension. The method of claim 1, The tilting control coil is an optical pickup actuator, characterized in that the winding is separated around the lens holder.