JP2003123285A - Optical pickup and disk drive device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the thickness of a two-axis actuator and improve the reliability of the operation of the two-axis actuator. SOLUTION: Both ends of the magnets 18 in the tracking direction are set to tracking coils 14, 14, respectively.
. Are formed as a pair of first magnetized portions 18a, 18a,.
A portion between the pair of first magnetized portions of the magnet is a second magnetized portion 18b whose surface facing the tracking coils 14, 14,... Is magnetized to a different pole from the first magnetized portion. , 1
8b, and a plurality of tracking coils 14, 1
Regarding 4,..., Inner portions 14a, 14a,.
. Are positioned opposite to the second magnetized portion of the magnet, and the outer portions 14b, 14b,... Located at both ends in the tracking direction of the magnet are opposed to the first magnetized portion of the magnet. To be located.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup and a disk drive device including the same. More specifically, the present invention relates to a technical field of an optical pickup for irradiating a laser beam emitted from a light emitting element to a recording surface of a disc-shaped recording medium via a rising mirror and an objective lens, and a disc drive device including the optical pickup.

[0002]

2. Description of the Related Art There is a disk drive device for recording and reproducing an information signal on a disk-shaped recording medium such as an optical disk.
When recording or reproducing an information signal, a biaxial actuator supported by a moving base of an optical pickup is operated to perform focusing adjustment and tracking adjustment of an objective lens.

Biaxial actuators generally have a fixed portion fixed to a moving base, a movable portion that is movable in the focusing direction and the tracking direction with respect to the fixed portion, and the movable portion that operates with respect to the fixed portion. And a magnetic circuit for performing the operation. The movable part is formed by winding a focusing coil and a tracking coil around a lens holder holding an objective lens. The magnetic circuit is composed of a yoke piece, a magnet attached to the yoke piece, a focusing coil of a movable part, a tracking coil, and the like.

A raising mirror is arranged on the movable base at a position directly below the objective lens held by the lens holder.

In the optical pickup, when laser light is emitted from the light emitting element arranged on the moving base,
The emitted laser light is made incident on the rising mirror via each predetermined optical component, the incident laser light is reflected by the rising mirror and is made to rise, and then is made to pass through the objective lens to the recording surface of the disk-shaped recording medium. Is irradiated. At this time, a driving current is supplied to each of the focusing coil and the tracking coil, the movable part of the biaxial actuator is operated with respect to the fixed part, and the laser light is focused on the recording track on the recording surface of the disk-shaped recording medium. Focusing adjustment and tracking adjustment are performed.

Biaxial actuators are roughly classified into a double-sided drive type and a single-sided drive type, depending on the arrangement of magnetic circuits.

In a double-sided drive type biaxial actuator, a pair of magnetic circuits are emitted from both sides of the movable part, that is, from the light emitting element with the objective lens held by the movable part sandwiched therebetween, and are incident on the rising mirror. Are arranged apart from each other in the optical axis direction of the laser light.

Therefore, in the double-sided drive type biaxial actuator, in order to prevent the optical path of the laser light incident on the rising mirror from interfering with the magnetic circuit, the yoke piece of the magnetic circuit and the magnet are concerned. It is arranged so as to be located above the optical path.

On the other hand, in the one-sided drive type biaxial actuator, the objective lens is held at one end of the lens holder, that is, the end opposite to the side where the fixing portion is arranged.

Therefore, in the one-sided drive type biaxial actuator, it is not necessary to consider the interference between the optical path of the laser beam incident on the rising mirror and the magnetic circuit.

However, in the one-sided drive type biaxial actuator, the objective lens is held at one end of the lens holder, so that the rigidity of the lens holder is insufficient to lower the high-frequency resonance frequency, the driving center of the movable part and the movable part. There is a problem such as a decrease in sensitivity due to weighting due to the placement of a balancer to match the center of gravity of the.

As described above, the biaxial actuator of the double-sided drive type generally has a larger thickness than the biaxial actuator of the single-sided drive type because it is necessary to dispose the yoke piece and the magnet of the magnetic circuit above the optical path. The one-sided drive type biaxial actuator has a problem that a high resonance frequency is lowered due to the position of the objective lens with respect to the lens holder and a sensitivity is lowered due to weighting. ing.

In the case of a biaxial actuator, if the width of the magnet in the same direction as the movable range of the movable part in the focusing direction is small, rolling occurs due to the generation of a moment. The occurrence of this rolling will be described below (see FIG. 9).

The magnets a have a horizontally long rectangular parallelepiped shape, and one magnet a is magnetized to the N pole and the other magnet a is magnetized to the S pole.

The tracking coils b, b, ... Provided on the lens holder are each formed by winding a coil wire in a substantially rectangular tube shape.
It is located so as to face both ends in the tracking direction. Tracking coils b, b, ...
Has a substantially inner half portion positioned corresponding to the magnets a and a, and a substantially outer half portion positioned so as to project laterally from both ends of the magnets a and a.

The tracking coil b is located on the central side in the longitudinal direction of the magnet a and extends vertically, a main thrust generating portion c, a return portion d parallel to the main thrust generating portion c, a main thrust generating portion c and It is composed of an upper side unnecessary thrust generating section e and a lower side unnecessary thrust generating section f which are located between the return sections d and extend left and right.

In the biaxial actuator, when a driving current is supplied to the tracking coils b, b, ...
The movable portion is moved in the tracking direction with respect to the fixed portion, and tracking adjustment is performed. For example, as shown in FIG. 9, an upward current is supplied to the main thrust generating portion c of the tracking coil b on the left back side, and an upward current is supplied to the main thrust generating portion c of the tracking coil b on the right back side. And rightward thrusts F1 and F1 on the main thrust generators c and c.
Occurs. At this time, current is also supplied to the tracking coils b on the left front side and the right front side as seen in FIG. 9, and thrust is generated in each part, but the description thereof is omitted.

At the same time, leftward thrusts F2 and F2 are generated in the return parts d and d, but the return parts d and d are positioned so as to project laterally from the magnet a.
The thrusts F1 and F1 are larger than the thrusts F2 and F2, and the movable part is moved to the right.

When the tracking adjustment is performed as described above, a leftward or rightward current flows through the upper unnecessary thrust generating portions e, e of the tracking coils b, b, and the lower unnecessary thrust generating portions f, f. The current flows to the right or left. Therefore, upward or downward unnecessary thrusts P1 and P1 are generated in the upper unnecessary thrust generating portions e and e, and downward or upward unnecessary thrusts P2 and P2 are generated in the lower unnecessary thrust generating portions f and f.
Occurs. The unnecessary thrusts P1, P1, P2, P2 are unnecessary forces for moving the movable portion in the tracking direction.

When the tracking adjustment is performed as described above, the focusing adjustment is also performed at the same time. Focusing adjustment is performed by moving the movable part in a direction in which the movable portion moves toward and away from the recording surface of the disc-shaped recording medium mounted on the disc table. When the focusing adjustment is performed, the tracking coils b, b ,. The position of the magnet with respect to the magnet a changes.

For example, if the lower unnecessary thrust generating portions f, f are projected below the magnet a when the movable portion is moved in the direction away from the recording surface of the disk-shaped recording medium, the lower unnecessary thrust is generated. Unnecessary thrust P generated in the generators f, f
2 and P2 are smaller than the unnecessary thrusts P1 and P1 generated in the upper unnecessary thrust generating portions e and e. Therefore, the movable part is shown in FIG.
As a result, a rotation moment Mt in the direction in which the tracking coils b on the right side move downward is generated, rolling occurs, and the operation of the biaxial actuator is hindered.

On the contrary, when the movable part is moved in the direction of contacting the recording surface of the disk-shaped recording medium, and the upper unnecessary thrust generating parts e, e project above the magnet a, the upper unnecessary thrust generating part. e, unnecessary thrusts P1 and P1 generated in e are unnecessary thrusts P2 and P generated in the lower unnecessary thrust generating portions f and f.
It becomes smaller than 2. Therefore, a rotational moment Mt 'is generated in the movable portion in the direction in which the left side tracking coils b, b in FIG. 9 move downward, and rolling occurs, which hinders the operation of the biaxial actuator.

In order to prevent such rolling, in the biaxial actuator, the widths of the magnets a, a in the focusing direction are set to the tracking coils b, b when the movable portion is moved in the focusing direction. , Must be so sized as not to project upward and downward from the magnets a, a.

[0024]

However, when the width in the focusing direction is set to the tracking coils b, b ,.
····································, because the size of the magnet a, a is not projected from the magnet a, the thickness of the biaxial actuator is correspondingly increased, which hinders the reduction in thickness. In particular, in the case of the bilateral drive type biaxial actuator described above, it is necessary to dispose the magnet of the magnetic circuit above the optical path of the laser beam from the light emitting element to the rising mirror, which makes it more difficult to reduce the thickness. .

On the other hand, in a biaxial actuator,
It is also necessary to solve the problems of the one-sided drive type, such as the lowering of the high-frequency resonance frequency and the lowering of sensitivity due to weighting, to improve the reliability of operation.

Furthermore, in recent years, disk-shaped recording media having two different formats, such as DVD (Digi
A disk drive device that records and reproduces an information signal by using one optical pickup is widely used for both a digital versatile disc (CD) and a compact disc (CD). In such a device, a biaxial actuator is movable. DV is the reference position for the disc-shaped recording medium
Since the case of D and the case of CD are different, the drive center of the movable portion and the center of the magnet cannot be matched at least at one position. Therefore, when a driving current is supplied to the tracking coil and a thrust is generated, a rotation moment is generated due to the deviation of the centers of both, and rolling occurs. Therefore, particularly in a disk drive device in which a disk-shaped recording medium having such two different formats is used, it is necessary to suppress the occurrence of rolling as much as possible and improve the operation reliability.

Therefore, it is an object of the optical pickup and disk drive device of the present invention to overcome the above-mentioned problems, to make the biaxial actuator thinner, and to improve the reliability of the operation of the biaxial actuator.

[0028]

In order to solve the above-mentioned problems, an optical pickup according to the present invention comprises a movable base which is movably supported in a radial direction of a disk-shaped recording medium mounted on a disk table, and an objective lens. And a biaxial actuator for performing focusing adjustment and tracking adjustment of laser light on a recording surface of a disc-shaped recording medium, the biaxial actuator holding a fixed portion fixed to a moving base and an objective lens. A focusing coil and a plurality of tracking coils are wound around, and a movable part is operated with respect to the fixed part in a focusing direction, which is a direction in which the recording surface of the disc-shaped recording medium is separated from and in contact with the recording part, and a tracking direction which is a radial direction of the disc-shaped recording medium. , The light of the laser light that is raised by the objective lens and is incident on the mirror A pair of yoke pieces that are spaced apart in the direction, and a pair of magnets that are attached to the pair of yoke pieces so as to face each other and that are arranged so as to face a plurality of tracking coils; Both ends in the tracking direction are formed as a pair of first magnetized portions whose surface sides facing the tracking coil are magnetized to have the same poles, and a portion between the pair of first magnetized portions of the magnet is tracked. A laser beam having a surface facing the coil formed as a second magnetized portion magnetized to a pole different from that of the first magnetized portion, and the plurality of tracking coils having their axial directions raised to enter a mirror. Of the magnet is wound so as to be substantially parallel to the optical axis direction of the magnet, and the inner portion of the magnet located on the central portion side in the tracking direction is opposed to the second magnetized portion of the magnet. And it is located, is obtained by the outer portion located on both ends in the tracking direction of the magnet to be located opposite the first magnetized portions of the magnet.

In order to solve the above-mentioned problems, the disk drive device of the present invention includes a movable base supported by the optical pickup so as to be movable in the radial direction of a disk-shaped recording medium mounted on a disk table, and an objective lens. And a biaxial actuator for performing focusing adjustment and tracking adjustment of the laser light on the recording surface of the disc-shaped recording medium, the biaxial actuator being provided with:
The focusing direction, which is the direction in which the fixed portion fixed to the moving base and the objective lens are held, and the focusing coil and the plurality of tracking coils are wound around and come in contact with the recording surface of the disc-shaped recording medium, and the radial direction of the disc-shaped recording medium A movable part that is operated in the tracking direction with respect to the fixed part, a pair of yoke pieces that are spaced apart in the optical axis direction of the laser beam that is incident on the rising mirror with the objective lens interposed therebetween, A pair of magnets that are attached to the yoke pieces of the magnets so as to oppose each other and that are arranged to oppose the plurality of tracking coils, and both end portions of the magnets in the tracking direction have the same surface side that opposes the tracking coils. It is formed as a pair of first magnetized portions magnetized to the poles, and a pair of first magnetized portions of the magnet are formed. The part between the magnetic parts is formed as a second magnetized part whose surface side facing the tracking coil is magnetized to a pole different from that of the first magnetized part, and the plurality of tracking coils are erected in the axial direction. The winding is performed so as to be substantially parallel to the optical axis direction of the laser light incident on the raising mirror, and the inner portion of the magnet located on the central portion side in the tracking direction faces the second magnetized portion of the magnet. The outer side portions of the magnet, which are located on both end sides in the tracking direction of the magnet, face the first magnetized portion of the magnet.

Therefore, in the optical pickup and the disk drive device of the present invention, a magnetic flux that connects the first magnetized portion and the second magnetized portion is generated in the magnet.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an optical pickup and a disk drive device according to the present invention will be described below with reference to the accompanying drawings.

The disk drive device 1 is constructed by arranging required members and mechanisms in an outer casing 2 (see FIG. 1),
A disc insertion opening (not shown) is formed in the outer casing 2.

A chassis (not shown) is arranged in the outer casing 2, and the disk table 3 is fixed to the motor shaft of the spindle motor attached to the chassis.

Parallel guide shafts 4 and 5 are attached to the chassis, and a lead screw (not shown) rotated by a feed motor (not shown) is supported.

The optical pickup 6 has a moving base 7, required optical parts provided on the moving base 7 and a biaxial actuator 8 supported on the moving base 7, and is provided at both ends of the moving base 7. The bearings 7a and 7b are slidably supported by the guide shafts 4 and 5, respectively (see FIG. 1). A nut member (not shown) provided on the moving base 7 is screwed onto the lead screw, and when the lead screw is rotated by the feed motor, the nut member is fed in the direction corresponding to the rotation direction of the lead screw, and the optical pickup 6 is moved to the disc. The disk-shaped recording medium 100 mounted on the table 3 is moved in the radial direction.

The biaxial actuator 8 comprises a fixed part 9 fixed on the moving base 7, a movable part 10 operated with respect to the fixed part 9, and a base member 1 provided on the moving base 7.
1 and 1 (see FIGS. 2 to 6).

The movable part 10 includes an objective lens 12, a focusing coil 13, tracking coils 14, 14 ,.
.. and the lens holder 15 around which is wound (see FIG. 4).

The lens holder 15 is provided with four winding portions 15a, 15a, ... Which are spaced apart from each other in the circumferential direction. The winding portions 15a, 15a ,. It is projected forward or substantially rearward. The focusing coil 13 is wound around the peripheral surface of the lens holder 15 so that the axial direction is the vertical direction, and the tracking coils 14, 14, ... Are wound portions 15a, 15a ,. Each of them is wound so that the axial direction thereof is substantially the front-back direction.

The tracking coil 14 is formed in a substantially rectangular tube shape, and is located inside and extends in the vertical direction.
a, a return portion 14b located outside and parallel to the main thrust generating portion 14a, an upper portion 14c located between the main thrust generating portion 14a and the return portion 14b, and extending leftward and rightward, and a lower portion 14d. (See Figure 6).

The movable portion 10 is supported by four metal linear suspensions 16, 16, 17, 17 so as to be positioned in the hollow, and the suspensions 16, 1,
Two of each of 6, 17, and 17 are attached to both side surface portions of the fixed portion 9 and both side surface portions of the movable portion 10 so as to be vertically separated from each other (see FIGS. 2 and 3). The suspensions 16 and 16 attached to one side face side and the suspensions 17 and 17 attached to the other side face side are viewed in a plane so that the distance between them increases as the movable portion 10 approaches the fixed portion 9. They are arranged in a letter shape (see FIGS. 2 and 3).

The movable part 10 includes a focusing coil 13
The tracking coil 1 is operated in the focusing direction, which is a direction in which the fixed portion 9 is separated from and in contact with the recording surface of the disk-shaped recording medium 100, in a direction according to the direction of the current flowing in
The fixed portion 9 is moved in the tracking direction, which is the radial direction of the disc-shaped recording medium 100, in the direction corresponding to the direction of the current flowing through the magnetic recording medium 4, 4 ,.

The base member 11 is made of a magnetic metal material,
An attached portion 11a attached to the moving base 7 and yoke pieces 11b and 11c protruding upward from both ends of the attached portion 11a in the front-rear direction are integrally formed (see FIG. 5). Magnets 18 and 18 are fixed to the surfaces of the yoke pieces 11b and 11c, respectively, which face each other,
The yoke pieces 11b and 11c are arranged in front and rear of the movable portion 10 (see FIGS. 2 and 3).

The magnets 18, 18 are in the left-right direction, that is,
It is formed in a rectangular parallelepiped shape that is long in the tracking direction, and the tracking coils 14 and 1 provided on the lens holder 15 are provided on the opposing surface sides of the magnets 18 and 18.
, 4 are located opposite to each other (see FIGS. 2, 3 and 6). Both left and right ends of the magnet 18 are formed as first magnetized portions 18a and 18a, respectively, of which surface sides facing the tracking coils 14 and 14 are magnetized to S poles having the same polarity. First magnetizing portion 1 of magnet 18
The portions between 8a and 18a are tracking coils 14 and 1
The surface side facing 4 is formed as a second magnetized portion 18b magnetized to an N pole different from the first magnetized portions 18a and 18a.

The left and right ends of the magnet 18 are first magnetized portions 18a, 18 which are magnetized into N poles having the same poles on the surfaces facing the tracking coils 14, 14, respectively.
the first magnetized portion 18 of the magnet 18
The portion between a and 18a is the tracking coil 14,
The surface side opposed to may be formed as a second magnetized portion 18b magnetized to an S pole having a different pole from the first magnetized portions 18a and 18a.

Tracking coils 14, 14, ...
Are the main thrust generators 14a, 14a,
Are positioned so as to face the left and right ends of the second magnetized portions 18b, 18b of the magnets 18, 18, respectively, and the return portions 14b, 14b, ...
Are respectively positioned so as to face the first magnetized portions 18a, 18a, ..., And the upper side portions 14c, 14c, ... And the lower side portions 14d, 14d ,. Magnetic parts 18a, 18a, ... And second magnetized parts 18b, 18
It is located in a state of straddling b (see FIG. 6).

As described above, in the biaxial actuator 8, two magnetic circuits including the yoke piece 11b and the magnet 18 and the yoke piece 11c and the magnet 18 are formed.

An opening 19 is formed in the base member 11 in a portion extending from the yoke piece 11b to the attached portion 11a, and the opening 19 is formed in the yoke piece 11b.
a and a mirror disposing portion 19b formed on the mounted portion 11a (see FIGS. 2, 5, and 7).

The light passage portion 19a is opened downward, and the upper opening edge of the magnet 18 is attached to the yoke piece 11b.
Is aligned with the lower end of the (see FIG. 7). Light passing portion 19a
A collimator lens 2 for collimating laser light emitted from a light emitting element (semiconductor laser) not shown in the figure
0 is arranged (see FIGS. 2, 5 and 7).

Thus, the opening 19 is formed in the base member 11.
By arranging the collimator lens 20 in the opening 19 and arranging the collimator lens 20 in the opening 19, it is not necessary to secure a dedicated arrangement space for the collimator lens 20 outside the biaxial actuator 8, and the optical pickup 6 can be downsized. be able to.

The mirror placement portion 19b of the opening 19 is opened forward, and the raising mirror 21 attached to the moving base 7 is placed below the objective lens 12 in the mirror placement portion 19b ( (See FIGS. 5 and 7).

In the disk drive device 1 configured as described above, when the disk table 3 is rotated with the rotation of the spindle motor, the disk-shaped recording medium 100 mounted on the disk table 3 is rotated,
At the same time, the optical pickup 6 moves the disc-shaped recording medium 10
The disk-shaped recording medium 100 is moved in the radial direction of 0 to perform a recording operation or a reproducing operation.

In the recording operation and the reproducing operation, the laser light emitted from the light emitting element provided on the moving base 7 is made incident on the rising mirror 21 through each predetermined optical component and the collimator lens 20, and is made incident. The laser beam P is reflected by the raising mirror 21 and is raised to be irradiated onto the recording surface of the disc-shaped recording medium 100 via the objective lens 12 (see FIG. 7). At this time, the driving current is the focusing coil 13 and the tracking coil 14,
Focusing adjustment and tracking adjustment are performed so that the laser light is supplied to each of 14, ..., And is focused on the recording track of the recording surface of the disk-shaped recording medium 100.

As described above, the tracking coil 14,
When a driving current is supplied to 14, ..., A downward current is supplied to the main thrust generating portion 14a of the tracking coil 14 on the left back side in FIG. When a downward current is supplied to the main thrust generator 14a, the main thrust generator 14a
A thrust force to the left is generated in a and 14a, and the return portion 14
Thrusts to the left, which are smaller than the thrusts generated in the main thrust generators 14a and 14a, are generated in b and 14b. Therefore,
The movable portion 10 is moved leftward with respect to the fixed portion 8 as viewed in FIG. At this time, as seen in FIG. 6, current is also supplied to the left front side and right front side tracking coils 14, 14 and thrust is generated in each part, but the description thereof is omitted.

On the contrary, the tracking coils 14, 14, ...
.. When a drive current is supplied to, the upward current is supplied to the main thrust generating portion 14a of the tracking coil 14 on the left rear side in FIG. 6, and the main thrust is generated on the tracking coil 14 on the right rear side. When an upward current is supplied to the portion 14a, the main thrust generating portions 14a, 14a
A rightward thrust is generated in the return thrusters 14b and 14b, and a rightward thrust smaller than the thrust generated in the main thrust generators 14a and 14a is generated in the return portions 14b and 14b. Therefore, the movable part 10 is moved to the right with respect to the fixed part 8 as viewed in FIG.

When the tracking adjustment is performed as described above, the upper side portion 1 of the tracking coils 14, 14 is
An inward or outward current flows through 4c, 14c and the lower side portions 14d, 14d.

On the other hand, at this time, magnetic flux is generated in the magnet 18 from the N pole to the S pole (see FIG. 8). Therefore, at the left and right ends of the magnets 18, 18, as shown in FIGS. 6 and 8, the magnetic fluxes M, M in the direction connecting the second magnetized portion 18b and the first magnetized portions 18a, 18a. ,
・ ・ Has occurred.

The directions of the magnetic fluxes M, M, ... Are determined by the upper parts 14c, 14c and the lower part 1 of the tracking coils 14, 14.
Since the current is substantially parallel to the currents flowing in 4d and 14d, no upward or downward thrust is generated in the upper portions 14c and 14c and the lower portions 14d and 14d. Therefore, no rolling moment occurs in the movable portion 10 due to the influence of the magnetic flux in the direction in which the first magnetized portions 18a, 18a move upward or downward, and rolling does not occur.

As described above, in the biaxial actuator 8, the movable portion 10 has the first magnetized portions 18a and 1a.
Since the rotational moment due to the influence of the magnetic flux in the direction in which 8a, ...
.. does not need to be sized so that the tracking coils 14, 14, ... Do not project upward or downward from the magnets 18, 18 when 0 is moved in the focusing direction, and the width of the magnets 18, 18 in the focusing direction Can be made smaller by that amount, and the optical pickup 6 can be made thinner by making the biaxial actuator 8 thinner.

Further, in consideration of the reduction in thickness, the one-sided drive type 2 in which the objective lens is held at one end of the lens holder
It is not necessary to use an axial actuator for the optical pickup 6, and there are problems of a single-sided drive type biaxial actuator. It is possible to secure the reliability of the operation of the biaxial actuator 8 without causing a problem such as a decrease in sensitivity due to weighting due to the arrangement of the balancer for matching.

In the biaxial actuator 8, as described above, the opening 19 is formed in the portion extending from the yoke piece 11b of the base member 11 to the attached portion 11a.
Therefore, the driving force on the yoke piece 11b side is weaker than the driving force on the yoke piece 11c side.
In the inertia region where 6, 17, 17 do not exert the spring force, the movable portion 10 is pivotally moved in the AA direction around a point on the yoke piece 11b side (see FIG. 3).

On the other hand, the suspensions 16, 16, 17,
In the spring region where 17 exerts a spring force, when the suspensions 16, 16, 17, 17 are arranged in parallel, the movable portion 10 is translated in the BB direction (see FIG. 3), so that inertia Due to the gain difference between the rotational movement in the area and the translational movement in the spring area, when the virtual axis extending in the vertical direction is considered, the movable portion 10 moves in the direction around the axis.
The so-called yawing that causes the rotation of the motor occurs and the phase fluctuation occurs.

Therefore, in the biaxial actuator 8, as described above, the suspensions 16 and 16 and the suspensions 17 and 17 are formed in a plane so that the distance between the suspensions 16 and 17 increases as the distance from the movable portion 10 to the fixed portion 9 increases. By arranging them in a V shape as seen, the movable portion 10 is rotated in the spring region as in the inertia region, and the phase fluctuation due to yawing is eliminated. Therefore, good sensitivity of the biaxial actuator 8 can be ensured, and the reliability of the operation of the biaxial actuator 8 can be improved.

In the above description, one member is divided into regions and magnetized to the N pole or the S pole, and the first magnetized portion 18a,
Magnet 1 in which 18a and the second magnetized portion 18b are formed
8 is shown, the first magnetized portions 18a, 18a and the second magnetized portion 18b may be separately formed, and these may be combined to form the magnet 18.

In this case, it suffices to combine the single pole magnetized parts, and it is not necessary to perform the magnetizing work by dividing one member into regions. Therefore, the magnet 18 can be easily manufactured, and A magnet in which two members are magnetized in different regions has a dead zone near the division surface, but a dead zone is not formed in a magnet formed by combining monopolar magnetized parts, so that the sensitivity of the biaxial actuator 8 is improved. Can be achieved.

The specific shapes and structures of the respective parts shown in the above-mentioned embodiments are merely examples of the embodiment when the present invention is carried out, and the technical form of the present invention is realized by them. The range should not be construed as limiting.

[0066]

As is clear from the above description, the optical pickup of the present invention moves in the radial direction of the disc-shaped recording medium mounted on the disc table and raises the laser beam emitted from the light emitting element. An optical pickup that irradiates a recording surface of a disc-shaped recording medium through a mirror and an objective lens, and includes a moving base supported movably in a radial direction of the disc-shaped recording medium mounted on a disc table, and an objective lens. A biaxial actuator for performing focusing adjustment and tracking adjustment of laser light on the recording surface of the disc-shaped recording medium is provided, and the biaxial actuator holds a fixed portion fixed to a moving base and an objective lens and performs focusing. A coil and multiple tracking coils are wound into a disk A laser that is incident on a stand-up mirror with a movable portion that is operated with respect to a fixed portion in a focusing direction that is a direction in and away from the recording surface of the medium and a tracking direction that is a radial direction of a disk-shaped recording medium, with an objective lens interposed therebetween. It has a pair of yoke pieces arranged apart from each other in the optical axis direction of the light, and a pair of magnets attached to the pair of yoke pieces so as to face each other and arranged so as to face the plurality of tracking coils. Then, both ends in the tracking direction of the magnet are formed as a pair of first magnetized portions whose surface sides facing the tracking coil are magnetized to have the same polarity, respectively, and between the pair of first magnetized portions of the magnet. Is formed as a second magnetized portion whose surface side facing the tracking coil is magnetized to a pole different from that of the first magnetized portion. Tsu King coils with wound so as to be substantially parallel to the optical axis of the laser light incident on the mirror that axially standing,
The inner side of the magnet located on the central side in the tracking direction is located opposite to the second magnetized section of the magnet, and the outer side located on both ends of the magnet in the tracking direction is the first magnetized side of the magnet. It is characterized in that it is positioned so as to face the section.

Therefore, since the rotational moment due to the influence of the magnetic flux is not generated in the movable portion of the biaxial actuator, the width of the magnet in the focusing direction can be reduced, and the biaxial actuator can be thinned to reduce the thickness of the optical pickup. be able to.

Further, in consideration of the reduction in thickness, a one-sided drive type 2 in which the objective lens is held at one end of the lens holder.
It is not necessary to use the axial actuator for the optical pickup, various problems of the one-side drive type do not occur, and the reliability of the operation of the biaxial actuator can be secured.

The disc drive device of the present invention comprises a disc table on which a disc-shaped recording medium is mounted and rotated, and a laser which is moved in the radial direction of the disc-shaped recording medium mounted on the disc table and emitted from a light emitting element. A disk drive device comprising: an optical pickup for irradiating light onto a recording surface of a disk-shaped recording medium through a rising mirror and an objective lens, wherein the optical pickup is a disk-shaped recording medium mounted on a disk table. The movable base is movably supported in the radial direction, and a biaxial actuator having an objective lens for performing focusing adjustment and tracking adjustment of the laser beam with respect to the recording surface of the disk-shaped recording medium is provided. A fixed part fixed to the base,
While holding the objective lens, the focusing coil and the plurality of tracking coils are wound around the fixed portion in the focusing direction, which is the direction in which the recording surface of the disc-shaped recording medium is separated and contacted, and the tracking direction, which is the radial direction of the disc-shaped recording medium. The movable part that is operated, the pair of yoke pieces that are disposed apart from each other in the optical axis direction of the laser light that is incident on the rising mirror with the objective lens interposed therebetween, and the pair of yoke pieces that face each other. A pair of magnets that are attached to each other and that are arranged to face the plurality of tracking coils, and both end portions in the tracking direction of the magnets have a pair of first magnets whose surface sides facing the tracking coils are magnetized to the same pole. The magnetized portion is formed as one magnetized portion, and the portion between the pair of first magnetized portions of the magnet is a tracking portion. Side facing the yl is formed as a second magnetized parts magnetized in the poles different from the first magnetized portion,
The plurality of tracking coils are wound so that the axial direction thereof is substantially parallel to the optical axis direction of the laser light incident on the rising mirror, and the inner portion located on the central portion side in the tracking direction of the magnet. Is positioned so as to face the second magnetized portion of the magnet, and the outer portions located at both ends of the magnet in the tracking direction are positioned so as to face the first magnetized portion of the magnet. Characterize.

Therefore, since the rotational moment due to the influence of the magnetic flux is not generated in the movable portion of the biaxial actuator, the width of the magnet in the focusing direction can be reduced, and the biaxial actuator can be thinned to reduce the thickness of the disk drive device. Can be planned.

Further, in consideration of the reduction in thickness, the one-sided drive type 2 in which the objective lens is held at one end of the lens holder.
It is not necessary to use the axial actuator for the optical pickup, various problems of the one-sided drive type do not occur, and the reliability of the operation of the disk drive device can be secured.

[Brief description of drawings]

FIG. 1 shows an embodiment of an optical pickup and a disc drive device according to the present invention together with FIGS. 2 to 8, and this diagram is a schematic plan view of the disc drive device.

FIG. 2 is an enlarged perspective view of a biaxial actuator.

FIG. 3 is an enlarged plan view of a biaxial actuator.

FIG. 4 is an enlarged perspective view showing a movable part of a biaxial actuator.

FIG. 5 is an enlarged perspective view showing a positional relationship between a base member, a rising mirror and a collimator lens.

FIG. 6 is an enlarged perspective view showing a positional relationship between a magnet and a tracking coil.

FIG. 7 is an enlarged cross-sectional view showing a positional relationship among a base member, a rising mirror, and a collimator lens.

FIG. 8 is a conceptual diagram showing a relationship between a magnetic flux generated in a magnetic circuit and a tracking coil.

FIG. 9 is an enlarged perspective view showing a relationship between a magnet and a tracking coil in a conventional biaxial actuator.

[Explanation of symbols]

1 ... Disk drive device, 3 ... Disk table, 6
... optical pickup, 7 ... moving base, 8 ... biaxial actuator, 9 ... fixed part, 10 ... movable part, 11b ... yoke piece, 11c ... yoke piece, 12 ... objective lens, 13 ... focusing coil, 14 ... tracking coil, 14
a ... Main thrust generating part (inner part), 14b ... Return part (outer part), 18 ... Magnet, 18a ... First magnetizing part, 18b ... Second magnetizing part, 21 ... Stand-up mirror, 1
00 ... Disc-shaped recording medium

Claims (2)

[Claims] 1. A disk-shaped recording medium mounted on a disk table is moved in a radial direction, and laser light emitted from a light emitting element is applied to a recording surface of the disk-shaped recording medium through a rising mirror and an objective lens. An optical pickup, which has a moving base supported in a radial direction of a disc-shaped recording medium mounted on a disc table, and an objective lens, for focusing and tracking a laser beam on a recording surface of the disc-shaped recording medium. A biaxial actuator for performing adjustment is provided. The biaxial actuator has a fixed portion fixed to a moving base, an objective lens, a focusing coil and a plurality of tracking coils, and a recording surface of a disc-shaped recording medium. Focusing direction, which is the direction of contact and separation with the disc A movable part that is operated in the tracking direction, which is the radial direction of the recording medium, with respect to the fixed part, and a pair of yokes that are arranged apart from each other in the optical axis direction of the laser light that is incident on the rising mirror with the objective lens sandwiched between them. And a pair of magnets that are attached to the pair of yoke pieces so as to face each other and that are arranged so as to face the plurality of tracking coils. The opposing surface sides are formed as a pair of first magnetized portions that are magnetized to the same polarity, and the portion between the pair of first magnetized portions of the magnet is such that the surface side facing the tracking coil is the first magnetized portion. The tracking coil is formed as a second magnetized portion magnetized to a pole different from that of the magnetized portion, and the plurality of tracking coils have a laser beam whose axial direction is incident on a rising mirror. While being wound so as to be substantially parallel to the optical axis direction of the laser beam, the inner portion of the magnet located on the central portion side in the tracking direction is positioned to face the second magnetized portion of the magnet, and An optical pickup characterized in that outer portions located on both end sides in the tracking direction are arranged to face the first magnetized portion of the magnet. 2. A disk table on which a disk-shaped recording medium is mounted and rotated, and a mirror which raises a laser beam emitted from a light-emitting element while moving in the radial direction of the disk-shaped recording medium mounted on the disk table. And a optical pickup for irradiating the recording surface of the disc-shaped recording medium through an objective lens, wherein the optical pickup is movable in a radial direction of the disc-shaped recording medium mounted on the disc table. And a biaxial actuator having an objective lens for performing focusing adjustment and tracking adjustment of laser light on a recording surface of a disc-shaped recording medium, the biaxial actuator being fixed to the movement base. The focusing coil holds the fixed part and the objective lens. A movable part that is moved relative to the fixed part in a focusing direction, which is a direction in which the tracking coil and a plurality of tracking coils are wound around and are in contact with and away from the recording surface of the disk-shaped recording medium, and a tracking direction that is a radial direction of the disk-shaped recording medium, A pair of yoke pieces that are arranged apart from each other in the optical axis direction of the laser light that is incident on the raising mirror with the objective lens interposed therebetween, and a plurality of tracking coils that are attached to the pair of yoke pieces so as to face each other. And a pair of magnets arranged to face each other, and both end portions in the tracking direction of the magnet are formed as a pair of first magnetized portions whose surface sides facing the tracking coil are magnetized to the same poles, respectively. In the portion between the pair of first magnetized portions of the magnet, the surface side facing the tracking coil is different from the first magnetized portion. It is formed as a second magnetized portion magnetized to a pole, and the plurality of tracking coils are wound so that their axial directions are substantially parallel to the optical axis direction of the laser light incident on the rising mirror. In addition, the inner portion of the magnet located on the central portion side in the tracking direction is located opposite to the second magnetized portion of the magnet, and the outer portion located on both end sides of the magnet in the tracking direction is the first magnet portion. A disk drive device characterized in that it is positioned so as to face the magnetized portion of the.