KR20050023756A - Optical pick-up actuator of slim type - Google Patents

Abstract

PURPOSE: A slim-type optical pickup actuator is provided to configure coils for tracking/focusing driving between two magnets, and to install a radial tilting coil and a magnet on other side of a lens holder, thereby enabling a multiaxial driving function. CONSTITUTION: A lens holder(202) is mounted with a protruded objective lens(201), and comprises a coil supporting portion(210) between the first and second receiving grooves. A focusing coil(203) is horizontally wound on the center of the coil supporting portion(210). Tracking coils(204) are vertically wound on both sides of the focusing coil(203). A radial tilting coil(205) is horizontally wound on other rear side of the lens holder(202). The first yoke(207a) is protruded from a pickup base(207). The first magnet(206) is attached to the first yoke(207a). The second yoke(207b) is protruded from the pickup base(207). The second magnet(213) is attached to the second yoke(207b).

Description

Optical pick-up actuator of slim type

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a slim optical pickup actuator capable of multi-axis driving, in particular by constructing a focusing and tracking magnetic circuit in the center of a lens holder and a radial tilting magnetic circuit on the other side of the lens holder.

An apparatus for reproducing recorded signals stored in an optical disk is called an optical disk drive. The optical disk drive generates an optical beam focused from an objective lens caused by surface vibration and eccentricity of the optical disk caused by rotation of the optical disk. The objective lens driving device is configured together with the optical pickup device so that the optical spot follows the center of the signal track of the optical disc to minimize the optical spot. Such an objective lens driving apparatus is called an optical pickup actuator, and the focusing and tracking of a beam focused on an information recording surface of an optical disk is performed by moving a movable part (hereinafter referred to as a lens holder) equipped with an objective lens up, down, left, and right. Servo).

1 is a conventional general slim optical pickup actuator.

Referring to FIG. 1, the optical pickup actuator 100 protrudes and mounts the objective lens 101 on one front surface of the lens holder 102, and a first accommodation groove 112 a is formed at the center of the lens holder 102. The focusing coil 103 is wound along the outer circumferential surface of the bobbin 110, and the tracking coil 104 is wound on one side left / right of the focusing coil 103.

A magnet 105 is attached to one surface (opposite surface) of the U-shaped yoke 106a protruding from the base 106, and the magnet 105 and the yoke 106a are connected to the first and second accommodation grooves 112a, respectively. 112b), the magnets 105 face each other.

The base 106, the frame 109, and the substrate 108 attached to the rear surface of the frame are fastened to the support portion 106b protruding from the base 106 by screws 120.

In addition, the lens holder 102 has a structure in which a pair of wire suspensions 107 are elastically supported between the substrate 111 and the frame 109 fixed to both side center portions thereof.

Here, the inner first and second receiving grooves 112a and 112b of the lens holder 102 are processed into a single groove, and by the bobbin 110 wound around the focusing coil 103 and the tracking coil 104. The divided bobbin 110 is fixed to the lens holder 102.

In such a structure, when the current is applied to the focusing coil 103 and the tracking coil 104, the coils are forced by the electromagnetic interaction of the magnet 105, the focusing coil 103, and the tracking coil 104. Received accordingly the lens holder 102 is interlocked. The direction in which the focusing coil 103 and the tracking coil 104 receive the force depends on Fleming's left hand law.

Therefore, when electromagnetic force acts on the coil by the interaction between the focusing coil 103 and the tracking coil 104 and the magnet 105, the bobbin 110 moves in the focusing direction Z or the tracking direction Y. do. Accordingly, as the lens holder 102 moves together with the bobbin 110, the objective lens 101 is moved to adjust a position at which an optical spot is formed on a disk (not shown).

As described above, the optical pickup actuator shown in FIG. 1 is a two-axis actuator that moves the lens holder in the tracking direction and the focusing direction. However, for high density discs (CDs, DVDs, CD-RWs, DVDRWs, etc.) where actuators increasingly require precision, the tilt margin is gradually reduced, and the assembly now reaches a limit that cannot meet optical tilt tolerances. Was done.

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.

FIG. 2 is a conventional optical pickup actuator capable of multiple axes (tracking, focusing, radial tilting), and the same parts as in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

Referring to FIG. 2, a radial magnet 120 is mounted on both sides of the lens holder 102, and a radial coil 121 is installed to face the radial magnet 120 and to be fixed to the base 106 (FIG. 1). . In an embodiment, the radial magnet 120 and the coil 121 may be installed opposite to each other.

Here, the movement of the lens holder 102 in the focusing and tracking directions is operated as described above, and the movement in the radial tilt direction is an electromagnetic interaction with the radial magnet 120 when a current is supplied to the radial coil 121. By rotation, the lens holder 102 rotates in the radial tilt direction through focusing up or down on the x-axis of the lens holder 102. That is, if the left side of the lens holder is up focused, the right side is down focused.

In addition, power is supplied to the coils 103, 104 and 121 for multi-axis driving of the lens holder 102. In the structure as shown in FIG. 2, power is supplied to the focusing and tracking coils 103 and 104 through the wire suspensions 103 and 104, and radial The tilting coil 121 is directly connected to the base side. As another example, when the radial tilting coil 121 is operated, three pairs of wire suspensions may be installed in the lens holder to supply power.

However, the lens protrusion type optical pickup actuators as shown in FIGS. 1 and 2 do not coincide with the tracks of the optical disc because the center of mass and the moving center of the lens holder 102 do not coincide with each other. . To this end, a mass balancer 130 is installed at the rear end of the lens holder 102 and operated as shown in FIG. 1.

As shown in FIGS. 3 and 4, the center of gravity of the lens holder 102 is between the left and right tracking coils 103, which is located between the two magnets 105 as shown in FIG. 4. The operating center point C1 of the first focusing coil 103a and the operating center point C2 of the tracking coil 104 are located at different points. This is due to the structure in which the focusing coil 103 passes between the two magnets 105 and the tracking coil 104 is attached to the left and right outer surfaces of the focusing coil 103.

In addition, the center of gravity G of the lens holder 102 including the bobbin 110 provided with the coils 103 and 104 is designed to be positioned between the operation center points C1 and C2 of the coils 103a and 104. .

In general, the center of gravity (C1, C2) and the center of gravity (G) of the coils (103a, 104) in one position to match the best performance of the actuator, the center of operation of the coils (103a, 104) If (C1, C2) does not coincide with the center of gravity (G) to any one of the operating center point, the operating characteristics of the non-matching operation center point is deteriorated, so that the weight center (G) in design It is designed to be located between the operation center points C1 and C2 of the coils 103a and 104.

However, even in this case, since the center of gravity of the lens holder 102, that is, the movement center G does not coincide, there is a problem in that the lens holder 102 is tilted and moved instead of being accurately moved during the focusing or tracking operation. In addition, since leakage fluxes generated in the opposite coil portions C3 and 103b of the focusing coil 103 are located on the rear surface of the magnet 105, they act as a force in the opposite direction to the focusing operation.

In addition, the magnetic flux is concentrated by the interaction with the magnet 105 in the first focusing coil portion 103a between the magnets 105, whereas the second focusing coil portion 103b on the back of the yoke 106a is a yoke. Since it is blocked by the 106a, it is not affected by the magnet 105, and the magnetic force line is actually leaked out of the yoke 106a. This leakage flux affects the second focusing coil 103b on the outside of the yoke 106a. In addition, the outer second focusing coil 103b is a useless coil that is not used for a focusing operation, and the sensitivity of the actuator is lowered due to an increase in mass and an increase in resistance of the winding coil. Therefore, the high-speed tracking capability due to the higher speed of the disk is a barrier.

On the other hand, since the center of gravity and the center of gravity (G) does not match during the movement in the track direction (T) by the tracking coil 104, a rolling mode is generated. That is, when the lens holder 102 is stopped, the overall center of gravity G of the actuator 100 coincides with the center of motion C2 of the lens holder 102. However, when the tracking coil is not in the neutral position, i.e., when moving in the tracking direction in the focusing operation state, a rotational moment occurs due to an imbalance of the up / down tracking force, resulting in a rolling mode in which the rolling coil is rolled.

In addition, since the conventional lens holder 102 is a mechanical structure itself, it has a unique vibration frequency, and when the actuator is excited at the vibration frequency, the lens holder 102 is resonated by a unique vibration mode of the lens holder 102. Since the vibration mode of the lens holder also causes the objective lens to vibrate, it directly affects the beam, making it difficult to control the actuator that must follow the disk. The inherent vibration mode of the lens holder 102 is a characteristic determined by the shape of the lens holder 102, so that the objective lens 101 vibrates together by the vibration mode of the lens holder itself, resulting in distortion of the beam. This adversely affects the control characteristics that follow the disk.

In the conventional structure as described above, rotational vibration modes such as the pitching mode and the rolling mode in the actuator adversely affect the phase and displacement of the fundamental frequency characteristics during focusing and tracking operations, thereby causing deterioration of the optical signal. Therefore, when the size of the magnet 105 is increased to increase the magnetic flux density in order to improve the AC sensitivity, the magnetic flux density increases due to the increase in the leakage magnetic flux, thereby limiting the magnetic flux density. Moreover, in the high speed and high density optical recording and reproducing apparatus, the pitching mode and the rolling mode phenomenon appear more seriously, and therefore an optical pickup actuator suitable for the optical recording and reproducing apparatus which is becoming high speed is required.

In addition, when the higher-order resonant frequency is included in the high frequency range, the objective lens is deformed as the bobbin is deformed, or the position of the objective lens in the lens holder is also changed, which causes the disc not to focus properly. There is a problem that can not be read properly to play.

The present invention has been made to solve the above problems, by configuring the coils for tracking and focusing driving between the two magnets for the operation of the lens holder, by installing a radial tilting coil and a magnet on the other side of the lens holder, It is an object of the present invention to provide a slim optical pickup actuator that can be driven.

The first purpose is to oppose a plurality of first magnets in the lens holder receiving groove, to install a focusing and tracking coil on the coil support of the lens holder facing the first magnet, and to face the second magnet multi-pole magnetized. It is an object of the present invention to provide a multi-axis actuator that does not install a mass balancer by providing a radial tilting coil at the other side, that is, at a mass balance position.

The third purpose is to allow the focusing and tracking coils and the radial tilting coils to be seated and fixed by using the coil support part integrally formed in the lens holder and the radial tilt projections on the other side without using a bobbin for supporting the coils. It is an object of the present invention to provide a slim optical pickup actuator which reduces the weight of the lens holder and secures driving reliability.

Slim optical pickup actuator according to the present invention for achieving the above object,

A lens holder mounted on one side of an objective lens for condensing light on the disk and moving in a tracking and focusing direction and a radial tilting direction;

A focusing and tracking magnetic circuit composed of a plurality of first magnets opposed to each other at a center of the lens holder and coils horizontally and vertically wound between the first magnets for operation in a focusing and tracking direction;

A radial tilting magnetic circuit comprising a radial tilting coil and a second magnet on the other side of the lens holder for operation in a radial tilting direction.

Preferably, the lens holder includes a coil support formed in the Y-axis direction to support the focusing coil and the tracking coil between the first and second accommodation grooves and the first and second accommodation grooves in the central portion thereof, and the first magnet is opposed to the first magnet. And a focusing coil installed at a center of the coil support part, a tracking coil installed at left / right sides, and a radial tilting coil disposed at a rear surface of the lens holder opposite to the second magnet.

Preferably, the first and second magnets are attached to inner surfaces of the first and second yokes protruding from the pickup base, respectively.

Preferably, the first magnet is a plurality of unipolar magnetized magnet, the second magnet is a multi-pole magnetized magnet.

Preferably, the radial tilting magnetic circuit includes a radial tilting protrusion and a radial tilting coil installed on the base on the other rear surface of the lens holder, a second yoke protruding from the pick-up base opposite the radial tilting coil, and a second magnet attached thereto. Characterized in that.

Preferably, the second yoke and the second magnet is characterized in that it is combined with a frame having a groove and a support base therein.

According to an embodiment of the present invention, a slim optical pickup actuator includes: a lens holder configured to move an objective lens on one side thereof; A monopole first magnet and a multipole magnetized single second magnet fixed on the pickup base and opposed to each other; A focusing coil disposed at a center of the lens holder and opposed to the first magnet, and a tracking coil disposed at left and right sides; A radial tilting coil facing the second magnet and installed on a rear surface of the other side of the lens holder; The lens holder is characterized in that it comprises a plurality of wire suspension for power supply.

Preferably, the radial tilting coil performs a mass balance function of the lens holder together with the radial tilt projection and the base protruding from the other rear surface of the lens holder.

Hereinafter, with reference to the accompanying drawings as follows.

5 is a perspective view of a slim type optical pickup actuator according to the present invention, FIG. 6 is a detailed configuration of the lens holder in FIG. 5, FIG. 7 is a configuration of the pickup base and the radial tilting magnetic circuit in FIG. 5, and FIG. 8 is An exploded perspective view of an optical pickup actuator.

5 to 8, a lens holder 202 mounted with an objective lens 201 protruding from one upper end thereof and having a coil support 210 between the first and second accommodation grooves 202a and 202b therein. Wow; A focusing coil 203 horizontally wound in a center at the center of the coil support 210; A tracking coil 204 vertically wound on both sides of the focusing coil 203; A radial tilting coil 205 wound horizontally on the other rear surface of the lens holder 202; A first yoke 207a facing the focusing and tracking coils 203 and 204 and protruding from the pick-up base 207 into the first and second receiving grooves 202a and 202b and a first magnet 206 attached thereto; A second yoke 207b protruding from the pickup base 207 and a second magnet 213 attached thereto so as to face the radial tilting coil; Three pairs of wire suspensions 208 for supporting both sides of the lens holder 202; A frame 212 that supports the wire suspension 208 and is fixed to the rear surface of the pickup base 207 and a main substrate 211 attached to the rear surface to supply power to the coils 203, 204, and 205. It is a configuration to include.

Here, a focusing magnetic circuit and a tracking magnetic circuit are formed by the first magnet 206 and the focusing and tracking coils 203 and 204, and a radial tilting magnetic circuit by the second magnet 213 and the radial tilting coil 205. Will be configured. Here, the first magnet 206 is unipolar, and the second magnet 213 is a multipole magnetized magnet.

Here, the lens holder 202 integrally forms a coil support 220 for supporting the coils 203 and 204 between the first and second receiving grooves 202a and 202b therein, and the lens holder 202 of the lens holder 202. The tilt coil protrusion 225 and the base 226 are integrally formed on the other rear surface.

Referring to the accompanying drawings, the lens protrusion optical pickup actuator configured as described above is as follows.

5 to 8, the optical pickup actuator 200 mounts the objective lens 201 on one side upper end of the lens holder 202, and between the two sides of the lens holder 202 and the frame 212. The pair (three rows of two) wire suspensions 208 are connected to support the lens holder 202 with a predetermined degree of freedom. In an embodiment, the wire suspension 208 may be variously connected in two pairs or three phases to support the lens holder 202.

The lens holder 202 is equipped with coils 203 and 204 for tracking and focusing operation at the center thereof, and radial tilting coils 205 for radial tilting on the other side thereof, and fixed first yokes 207a to the coils 203 and 204. ) And the magnet 206 face each other, and the fixed tilting coil 205 faces the fixed second yoke 207b and the magnet 213.

To this end, first and second accommodation grooves 202a and 202b are formed at the other side of the lens holder 202, and the focusing coil 203 is formed on the coil support 220 between the accommodation grooves 202a and 202b. The tracking coil 204 is arranged in the Y-axis direction, and the first magnet 206 and the first yoke 207a face each other in each of the receiving grooves 202a and 202b at positions opposite to the coils 203 and 204. This is the structure you are looking at. That is, the first magnet 206 is a structure attached to the first yoke 207a protruding from the pickup base 207 in the form of a "U".

In addition, in order to move in the radial tilting direction of the lens holder 202, the radial tilting coil 205 is fitted to the projection 225 of the "ㅁ" shape on the other rear surface of the lens holder 202, the radial tilting The second yoke 207b protruding from the pick-up base 207 and the magnet 213 attached thereto constitute a radial tilting magnetic circuit at a position opposite to the coil 205.

As shown in FIG. 6, the lens holder 202 has a coil support 220 between the first and second accommodation grooves 202a and 202b and the first and second accommodation grooves 202a and 202b. Form integrally.

Here, the coil support 220 is a structure formed in the Y-axis direction between the inner periphery of the lens holder 202, the focusing coil base 221 and the guide protrusion 222 on which the focusing coil 203 is seated at the center thereof. The tracking coil 204 is formed on the coil base 223 formed between the guide protrusion 222 and the holder inner surface 224. In an embodiment, the coil bases 221 and 223 may be formed to have different heights or two or more to have substantially the same height, and thus the coil base height may be adjusted. The coil support 220 is integrally formed with the lens holder 202 body and a plastic material. Here, the coil support 220 is integrally formed with the lens holder 202 so that the coil support 220 supports both side surfaces of the lens holder 202 at the positions where the coils 203 and 204 are installed. It can reduce the deformation of.

Then, the radial tilting coil 205 is fixed to the tilt coil protrusion 225 having a "wh" shape projecting in the rear direction on the rear of the lens holder 202. A second yoke 207b and a second magnet 213 attached to the second yoke 207b are installed in the pickup base 207 at the position opposite to the radial tilting coil 205.

That is, as shown in FIGS. 7 and 8, the pickup base 207 is provided with a plurality of first yokes 207a and a single second yoke 207b, respectively (FIG. 7A), and the first yoke ( The first magnet 206 is attached to the position facing the focusing and tracking coils 203 and 204 with each other (FIG. 8), and the second yoke 207b has a second position opposite the radial tilting coil 205 with the second yoke 207b. The magnet 213 is attached (FIGS. 7B and 7C). Here, the structure that moves by attaching relatively light coils to the lens holder is called a moving coil method. On the contrary, a method of attaching and operating a magnet to the lens holder may be used as a moving magnet method.

In addition, the second yoke 207b is formed in a rectangular groove (not shown) formed inside the frame 212, and a coil base (not shown) in which a bottom surface of the second magnet 213 is formed inside the rectangular groove. It is supported by the structure and attached to the yoke (207b) inwardly. As an example, the frame may be provided with a groove having a “C” shape.

On the other hand, the rear side of the lens holder 202 has a main board 211 attached to the back of the frame 212 and a substrate (or contact) 210 coupled to both sides of the lens holder 202. Are electrically connected to each other to supply power to the coils 203, 204, and 205. Here, the wire suspensions 208 are fixed to both side wire fixing portions 209 of the lens holder 208 and then connected to the substrate 210. At this time, the substrate 210 has a T-shape as shown in FIG. 12, and electrically connects the coils 203, 204, and 205 to each end through the coil contacts 210a, 210b, and 210c to form a straight loop.

As such, the lens holder 202 has the focusing coil 203 at the center, and the tracking coil 204 is disposed at the left and right sides of the focusing coil 203, and the radial tilting coil 205 is disposed at the rear of the lens holder. do. Here, the focusing coil 203 and the radial tilting coil 205 are horizontally wound and the tracking coil 204 is vertically wound. Here, the coils 202, 203, 205 and the fixing protrusions or the base by using an epoxy resin or the like to fill in the space between each coil and the coil guide protrusions are tightly fixed. In addition, the focusing coil 203 and the tracking coil 204 may be seated and fixed to the coil support part 220 in a state of being tightly coupled by a bonding process in advance. In addition, by removing the bobbin (bobbin) for fixing the coils (203, 204, 205), it is possible to reduce the weight of the lens holder than conventional.

The first and second accommodating grooves 202a and 202b of the lens holder 202 are attached to the U-shaped first yoke 207a and the U-shaped yoke inner surface (that is, the opposing surface) formed in the base 207. As the first magnet 206 protrudes, both of the wound side surfaces of the horizontally wound focusing coil 203 face the first magnet 206, and both of the wound side surfaces of the tracking coil 204 vertically wound in a square shape are Opposes the first magnet 206. In addition, both winding sides of the radial tilting coil 205 are opposed to the second magnet 206 magnetized with multipole NS: SN. In an embodiment, the first magnet is a single pole (N: S), and the distance between the two magnets 206 corresponds to approximately 3.6 mm.

As shown in FIG. 8, the present invention locates the focusing and tracking coils 203 and 204 between the first magnets 206 and the radial tilting coil 205 at a mass balance position facing the multipole magnetized second magnets 213. ), A focusing and tracking magnetic circuit by the first magnet 206 and the focusing coil 203 and the left and right tracking coils 204, and the second magnet 213 and the radial tilting coil 205. To form a radial tilting magnetic circuit.

In addition, since the magnets 206 and 213 are larger than the opposing areas of the coils 203, 204 and 205, the magnetic flux distribution according to the focusing, tracking and radial tilting operations can be balanced.

In other words, due to the imbalance of the center of gravity of the lens holder assembly, the existing lens holder is essentially mounted on the rear side of the lens holder. In order to solve this problem, the present invention provides a tilt coil protrusion 225, a base 226, and a radial tilting coil 205 to the rear of the lens holder 202, so that the center of gravity can be made to be centered as a whole.

8 and 12, when a current is applied to the focusing coil 203 and the tracking coil 204 disposed between the first magnets 206, the first magnets 206 face each other. The coils 203 and 204 are energized by the electromagnetic interaction between the focusing coil 203 and the tracking coil 204, thereby causing the lens holder 202 to operate. By placing the focusing coil 203 at the center of the two magnets 206 and the tracking coil 204 at the left and right sides, a phenomenon such as a rolling mode and a pitching mode caused by a mismatch between the center of gravity and the center of gravity can be solved. have.

As shown in FIGS. 9, 10, and 11, when a current is applied to the radial tilting coil 205 facing the multipole magnetized second magnet 213, the radial tilting of the multipole magnetized second magnet 213 is performed. The coil 205 is forced by the electromagnetic interaction of the coil 205, thereby causing the lens holder 202 to move in the radial tilting direction. The direction in which the magnets 206 and 213 and the coils 203, 204 and 205 are subjected to the force follows Fleming's left hand law. 9 is a configuration in which the upper yoke 217 is provided on the lens holder 202 shown in FIG. 5.

Therefore, when electromagnetic force acts on the coil by the interaction of the focusing coil 203 and the tracking coil 204, the radial tilting coil 205 and the magnets 206 and 213, the coil structure (coil body) and the moving body (lens holder) Moves in the focusing direction Z or tracking direction Y and the radial tilting direction (rotation in the X-axis direction). Accordingly, the objective lens 201 mounted by the movement of the lens holder 202 is moved to adjust the position where the light spot is formed on the disk (not shown). Here, since the distance between the first magnets 206 is wider than the conventional one, the back EMF generated between the first magnets 206 may be eliminated as in the prior art, thereby improving performance.

The operation of the optical pick-up actuator will be described with reference to the structure of FIG. 5 and the circuit diagram of FIG. 12 as follows.

First, the three pairs of wire suspensions 208 interconnect the substrate 210 and the main substrate 211 and apply current in a forward or reverse direction through the coils 203, 204, and 205 and the substrate contacts 210a, 210b, and 210c, respectively. .

At this time, when currents F + and F- in a predetermined direction are applied to the focusing coil 203, the magnetic flux distribution is directed toward the center of the left / right side from the side facing the first magnet 206, thereby performing the focusing operation. . This is because the leakage flux in the focusing coil of the focusing coil in the back of the yoke (see Fig. 1) in the present invention can use the entire focusing coil to eliminate the leakage flux and bring a large amount of the main magnetic flux.

In addition, when currents T + and T− in a predetermined direction are applied to the tracking coil 204, the tracking coil 204 is directed from the side facing the first magnet 206 to the center of the tracking upper and lower sides, thereby performing the tracking operation.

10, 11, and 12, when the currents R + and R− in a predetermined direction are applied to the radial tilting coil 205, the coil 205 faces the second magnet 206. In the opposite direction toward the center of the left / right side, the right side is down-focused if the left is up focusing. On the contrary, the right side is down-focused if the left is down-focused.

As described above, according to the slim optical pickup actuator according to the present invention, by placing a focusing coil at two magnet centers and a tracking coil at left / right sides, the center of gravity of the actuator and the center of force according to the tracking and focusing driving are moved in the X axis direction. It can be matched to one point, it is effective to improve the driving reliability and servo stability than the existing.

Another effect is to reduce the weight of the lens holder by removing the bobbin.

Another effect is that the coil support is integrally formed with the lens holder, thereby supporting both sides of the lens holder at the position where the coil is installed, thereby reducing deformation of the lens holder.

Another effect is that since the tracking and focusing coils are collected between the magnets, the distance between the first magnets can be increased, thereby removing the counter electromotive force.

Another effect is to arrange a focusing coil at two magnet centers and a tracking coil at left and right sides, thereby solving a phenomenon such as a rolling mode and a pitching mode caused by a mismatch between the center of gravity and the center of gravity.

Another effect is that a radial tilting coil and a second magnet are provided at a position opposite to the rear end of the lens holder, so that the second magnet can be operated in the radial tilting direction together with the focusing and tracking driving. In addition, since the radial tilting coil is installed at the mass balancer position, the operation is easy and the cost and productivity can be improved.

1 is a perspective view showing the structure of a conventional slim optical pickup actuator.

Figure 2 is a perspective view of a slim optical pickup actuator according to another conventional embodiment.

3 is a cross sectional view of FIG. 1.

4 is a plan view of a coil and a magnet for showing a center of gravity and a center of force in a conventional actuator.

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

6A and 6B are detailed configuration diagrams of the lens holder of FIG. 5.

7A, 7B, and 7C illustrate a pickup base and a radial tilting magnetic circuit of FIG. 5;

8 is an exploded perspective view of a slim type optical pickup actuator according to an embodiment of the present invention.

9 is a state diagram of the combination of the slim optical pickup actuator according to an embodiment of the present invention.

10 and 11 are views showing an operation example by the radial tilting circuit according to the present invention.

12 is a view showing a three-axis drive principle according to the actuator of the present invention.

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

200 ... actuator 201 ... objective lens

202 Lens holder 203 Focusing coil

204 ... tracking coil 205 ... radial tilting coil

206,213 Magnet 207 Base

207a, 207b ... York 208 ... wire suspension

209 wire fixing 210,211 substrate

212 Frame 220 Coil Support

202a, 202b ... Accepting groove 225 ... Radial coil support

Claims (8)

A lens holder mounted on one side of an objective lens for condensing light on the disk and moving in a tracking and focusing direction and a radial tilting direction; A focusing and tracking magnetic circuit composed of a plurality of first magnets opposed to each other at a center of the lens holder and coils horizontally and vertically wound between the first magnets for operation in a focusing and tracking direction; And a radial tilting magnetic circuit comprising a radial tilting coil and a second magnet on the other side of the lens holder for operation in a radial tilting direction. The method of claim 1, The lens holder includes a coil support formed in a Y-axis direction so as to support a focusing coil and a tracking coil between the first and second accommodation grooves and the first and second accommodation grooves in a central portion thereof, and to face the first magnet. A focusing coil installed at the center of the support and a tracking coil installed at the left and right sides, and a radial tilting coil facing the second magnet and installed at the rear of the lens holder, the slim type optical pickup actuator. The method of claim 1, And the first and second magnets are attached to inner surfaces of the first and second yokes protruding from the pickup base, respectively. The method of claim 1, The first magnet is a plurality of single-pole magnetized magnet, the second magnet is a multi-pole magnetized magnet, characterized in that the slim pick-up actuator. The method of claim 1, The radial tilting magnetic circuit may include a radial tilting protrusion and a radial tilting coil installed at a base on the other rear surface of the lens holder, a second yoke protruding from the pickup base opposite the radial tilting coil, and a second magnet attached thereto. A slim type optical pickup actuator. The method of claim 5, And the second yoke and the second magnet are combined with a frame having a groove and a support base therein. A lens holder for mounting and operating the objective lens on one side; A monopole first magnet and a multipole magnetized single second magnet fixed on the pickup base and opposed to each other; A focusing coil disposed at a center of the lens holder and opposed to the first magnet, and a tracking coil disposed at left and right sides; A radial tilting coil facing the second magnet and installed on a rear surface of the other side of the lens holder; And a plurality of wire suspensions for supporting the lens holder and for supplying power. The method of claim 7, wherein And the radial tilting coil performs a mass balance function of the lens holder together with means for supporting the coil at the other rear surface of the lens holder.