JP2005302161A - Optical pickup and disk drive apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve sensitivity of an objective lens drive apparatus and to miniaturize and thin the apparatus. <P>SOLUTION: The objective lens drive apparatus 8 is provided with a fixed block 11 arranged on a fixed plate 10 provided on a movement base 7, a movable block 12 holding an objective lens 22 and operated in the focusing direction, the tracking direction, and the tilt direction, supporting springs 20, 20 supporting the movable block for the fixed block, a first magnetic circuit 27 operating the movable block in the focusing direction or the tracking direction, and a second magnetic circuit 30 operating the movable block in the tilt direction, the second magnetic circuit has a pair of tilt magnets 29 in which two poles are magnetized so that N poles 29a, 29a, S poles 29b, 29b are positioned in the focusing direction, and a pair of tilt coils 16, 16 which are opposed to the tilt magnets and in which a coil winding axis direction is a tangential direction, the tilt magnets are provided at the movable block, the tilt coils are provided at the fixed block, and the objective lens and the second magnetic circuit are positioned at an opposite side in the tangential direction holding the first magnetic circuit between them. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical pickup and a disk drive device. More particularly, the present invention relates to a technical field of an optical pickup having an objective lens driving device in which a movable block is moved in three directions of a focusing direction, a tracking direction, and a tilt direction with respect to a fixed block, and a disk drive device including the optical pickup.

  2. Description of the Related Art There is a disk drive device that records and reproduces information signals on and from a disk-shaped recording medium such as an optical disk. Such a disk drive device moves in the radial direction of the disk-shaped recording medium and moves to the disk-shaped recording medium. An optical pickup for irradiating laser light is provided.

  The optical pickup is provided with an objective lens driving device, and the objective lens driving device moves the objective lens held by the movable block in a focusing direction which is a direction in which the recording surface of the disc-shaped recording medium is separated from or contacting the optical pickup. Focusing adjustment is performed and the objective lens is moved in the tracking direction, which is substantially the radial direction of the disk-shaped recording medium, to perform tracking adjustment, and the spot of the laser beam irradiated to the disk-shaped recording medium through the objective lens is recorded in the disk-shaped recording. The light is focused on the recording track of the medium.

  As described above, in an optical pickup, focusing adjustment and tracking adjustment are generally performed by an objective lens driving device, but in recent years, in order to improve followability of a laser beam spot to a recording track, etc. In addition to the biaxial adjustment of focusing adjustment and tracking adjustment, the movable block can be tilted with respect to the recording surface of the disk-shaped recording medium, and adjustments can be made when surface fluctuations occur on the rotating disk-shaped recording medium. An objective lens driving device called a so-called triaxial actuator has been developed. Therefore, in an objective lens driving device called a three-axis actuator, the movable block is perpendicular to the focusing direction, the tracking direction, and the radial direction of the disk-shaped recording medium with respect to the fixed block, and the tangential direction of the disk-shaped recording medium. It is moved in the tilt direction, which is the direction around the axis extending in the tangential direction.

  Conventionally, the following types of objective lens driving devices called triaxial actuators have been developed.

  For example, a movable block that holds the objective lens is movably supported by a fixed block via a support spring, and a tilt coil for tilting the movable block with respect to the fixed block is provided on the movable block and faces the tilt coil. A tilt magnet is provided on the fixed block. A type in which such a tilt coil is provided in the movable block is called a moving coil type.

  In the moving coil type objective lens driving device, a driving current is supplied to each of a focusing coil for focusing adjustment, a tracking coil for tracking adjustment, and a tilt coil for tilt adjustment arranged on the movable block side. Two support springs are required. Therefore, the movable block is supported by the fixed block via a total of six support springs.

  On the other hand, as a three-axis actuator of a type different from the moving coil type, the movable block holding the objective lens is supported by the fixed block through a support spring so as to be movable, and the movable block is tilted with respect to the fixed block. The tilt coil is provided on the fixed block, and a tilt magnet positioned opposite the tilt coil is provided on the movable block (see, for example, Patent Document 1). A type in which such a tilt magnet is provided in the movable block is called a moving magnet type.

  In the moving magnet type objective lens driving device, since the tilt magnet is provided in the movable block, the weight of the movable block is larger than that of the moving coil type objective lens driving device. Therefore, there is an advantage that the number of parts can be reduced and the assembling work can be facilitated as compared with a moving coil type objective lens driving device.

JP 2000-222755 A

  However, in the objective lens driving device described in Patent Document 1, the tilt magnet provided in the movable block is single-pole magnetized, and the winding direction of the tilt coil provided in the fixed block is the focusing direction. Therefore, the movable block is moved in the tilt direction by the relationship between the drive current flowing in about a quarter of the tilt coil wound in a rectangular tube shape and the magnetic flux of the magnet. Therefore, there are few portions of the tilt coil used for tilt adjustment, and there is a possibility that the sensitivity is lowered.

  In order to cope with this decrease in sensitivity, it is necessary to use a magnet having a strong magnetic force or to supply a high driving current to the tilt coil, which increases the manufacturing cost and power consumption of the objective lens driving device. Etc.

  Furthermore, when the tilt coil is arranged so that the winding axis direction becomes the focusing direction, the space for arranging the tilt coil in the tangential direction increases, and the objective lens driving device becomes larger in the tangential direction, thereby reducing the size. In addition to obstructing, there is also a problem that the support state of the movable block becomes unstable.

  On the other hand, in an objective lens driving device, generally, laser light emitted from a light source is guided to an objective lens by a rising mirror disposed on the opposite side of the disk-shaped recording medium with a movable block interposed therebetween. In this case, for example, in a type in which a magnetic circuit composed of a coil, a magnet, or the like is arranged around the objective lens, the optical path of the laser beam for entering the rising mirror is positioned below the magnetic circuit. Accordingly, the thickness of the objective lens driving device increases, and the thickness cannot be reduced. In particular, an optical pickup used for a portable device is highly demanded to be thinned, so that it is a big problem to hinder the thinning.

  Accordingly, an object of the optical pickup and the disk drive device of the present invention is to overcome the above-mentioned problems and to improve the sensitivity and reduce the size and thickness of the objective lens driving device.

  In order to solve the above-described problems, an optical pickup and a disk drive device according to the present invention include a fixed plate provided on a moving base, and a fixed plate disposed on the fixed plate and fixed to the moving base. A fixed block, a focusing direction which is a direction in which the objective lens is held and the recording surface of the disk-shaped recording medium is separated from the fixed block, a tracking direction which is a substantially radial direction of the disk-shaped recording medium, and a disk-shaped recording medium A movable block that is operated in a tilt direction, which is a direction around an axis extending in a tangential direction perpendicular to the radial direction and tangential to the disk-shaped recording medium, and the movable block is movably supported with respect to the fixed block A plurality of support springs and a movable block in the focusing direction or the tracking direction A first magnetic circuit to be operated and a second magnetic circuit to move the movable block in the tilt direction are provided, and the second magnetic circuit has two poles so that the N pole and the S pole are positioned in the focusing direction. A pair of tilt magnets that are magnetized and spaced apart in the radial direction, and a pair of tilt coils that are respectively opposed to the pair of tilt magnets and whose winding axis direction is the tangential direction. A magnet is provided on the movable block, a pair of tilt coils is provided on the fixed block, and the objective lens and the second magnetic circuit are positioned on the opposite sides in the tangential direction across the first magnetic circuit. is there.

  Therefore, in the optical pickup and the disk drive device of the present invention, the portion that can be used for tilt adjustment of the tilt coil increases.

  The optical pickup of the present invention is an optical pickup including a moving base that is moved in the radial direction of a disk-shaped recording medium mounted on a disk table, and an objective lens driving device that is disposed on the moving base. The driving device includes a fixed plate provided on the moving base, a fixed block disposed on the fixed plate and fixed to the moving base, an objective lens, and a disc-shaped recording medium with respect to the fixed block. Extending in a focusing direction, which is a direction away from or in contact with the recording surface, a tracking direction, which is a substantially radial direction of the disc-shaped recording medium, and a tangential direction which is perpendicular to the radial direction of the disc-shaped recording medium and is a tangential direction of the disc-shaped recording medium A movable block that is moved in a tilt direction, which is a direction around the axis of the shaft, and the movable block A plurality of support springs that are movably supported with respect to the block, a first magnetic circuit that moves the movable block in the focusing direction or the tracking direction, and a second magnetic circuit that moves the movable block in the tilt direction. The second magnetic circuit includes a pair of tilt magnets magnetized so that the N pole and the S pole are positioned in the focusing direction and spaced apart from each other in the radial direction, and facing the pair of tilt magnets, respectively. And the pair of tilt magnets are provided on the movable block, the pair of tilt coils are provided on the fixed block, and the first magnetic circuit is provided. The objective lens and the second magnetic circuit are positioned on the opposite side in the tangential direction across the And butterflies.

  Therefore, since the tilt coil is arranged so that the winding axis direction is the tangential direction, the portion of the tilt coil that can be used as a portion for generating thrust in the tilt direction on the movable block is large. The sensitivity of the movable block can be improved.

  In addition, since the sensitivity of the movable block can be improved, it is not necessary to use a magnet having a strong magnetic force, and it is not necessary to supply a high driving current to the tilt coil, which reduces the manufacturing cost of the objective lens driving device. Reduction and power consumption can be reduced.

  Further, since the winding direction of the tilt coil is not the focusing direction, the arrangement space for the tilt coil in the tangential direction is small, and the size of the objective lens driving device in the tangential direction can be reduced.

  Furthermore, since the objective lens and the second magnetic circuit are arranged on the opposite side in the tangential direction across the first magnetic circuit, the rising mirror is set to the same height as the first magnetic circuit. Therefore, the objective lens driving device can be reduced in thickness. Such thinning is particularly suitable for an optical pickup used in a portable device.

  In addition, since the tilt magnet is provided in the movable block and the tilt coil is provided in the fixed block, a support spring for supplying power to the tilt coil is unnecessary, and accordingly, the number of parts is reduced and the objective lens driving device is provided. Assembling property can be simplified.

  In the invention described in claim 2, since a tilt yoke disposed on the opposite side of the tilt magnet in the tangential direction with a tilt coil sandwiched between a part of the fixed plates is provided, There is no need to provide a tilt yoke, and the portion for fixing the fixing block and the tilt yoke can be shared, and the number of parts can be reduced.

  In the invention described in claim 3, since the back yoke is disposed on the surface opposite to the surface facing the tilt coil of the tilt magnet, it is possible to improve the sensitivity of the movable block during tilt adjustment. .

  Further, the leakage magnetic flux from the tilt magnet is reduced, the second magnetic circuit is hardly affected by the first magnetic circuit, and the tilt of the movable block with respect to the fixed block due to the influence of the leakage magnetic flux can be prevented.

  The disk drive device of the present invention includes a disk table on which a disk-shaped recording medium is mounted, and an optical pickup that irradiates the disk-shaped recording medium mounted on the disk table with a laser beam through an objective lens. The pickup is a disk drive device having a moving base moved in the radial direction of a disk-shaped recording medium mounted on a disk table, and an objective lens driving device arranged on the moving base, the objective lens driving device comprising: A fixed plate provided on the moving base, a fixed block disposed on the fixed plate and fixed to the moving base, an objective lens is held, and the recording surface of the disc-shaped recording medium is held with respect to the fixed block. Focusing direction, which is the direction of contact, and torque direction, which is the substantially radial direction of the disk-shaped recording medium A movable block that is operated in a tilt direction that is a direction around an axis extending in a tangential direction that is perpendicular to the racking direction and the radial direction of the disk-shaped recording medium and that is a tangential direction of the disk-shaped recording medium, and the movable block is fixed A plurality of support springs that are movably supported with respect to the block, a first magnetic circuit that moves the movable block in the focusing direction or the tracking direction, and a second magnetic circuit that moves the movable block in the tilt direction. The second magnetic circuit includes a pair of tilt magnets magnetized so that the N pole and the S pole are positioned in the focusing direction and spaced apart from each other in the radial direction, and facing the pair of tilt magnets, respectively. And a pair of tilt coils whose winding axis direction is the tangential direction. The net is provided on the movable block, the pair of tilt coils is provided on the fixed block, and the objective lens and the second magnetic circuit are positioned on the opposite sides in the tangential direction across the first magnetic circuit. It is characterized by that.

  Therefore, since the tilt coil is arranged so that the winding axis direction is the tangential direction, the portion of the tilt coil that can be used as a portion for generating thrust in the tilt direction on the movable block is large. The sensitivity of the movable block can be improved.

  In addition, since the sensitivity of the movable block can be improved, it is not necessary to use a magnet having a strong magnetic force, and it is not necessary to supply a high driving current to the tilt coil, which reduces the manufacturing cost of the objective lens driving device. Reduction and power consumption can be reduced.

  Further, since the winding direction of the tilt coil is not the focusing direction, the arrangement space for the tilt coil in the tangential direction is small, and the size of the objective lens driving device in the tangential direction can be reduced.

  Furthermore, since the objective lens and the second magnetic circuit are arranged on the opposite side in the tangential direction across the first magnetic circuit, the rising mirror is set to the same height as the first magnetic circuit. Therefore, the objective lens driving device can be reduced in thickness. Such thinning is particularly suitable for a portable disk drive device.

  In addition, since the tilt magnet is provided in the movable block and the tilt coil is provided in the fixed block, a support spring for supplying power to the tilt coil is unnecessary, and accordingly, the number of parts is reduced and the objective lens driving device is provided. Assembling property can be simplified.

  In the invention described in claim 5, since a tilt yoke disposed on the opposite side of the tilt magnet in the tangential direction with a tilt coil sandwiched between a portion of the fixed plate is provided, There is no need to provide a tilt yoke, and the portion for fixing the fixing block and the tilt yoke can be shared, and the number of parts can be reduced.

  In the invention described in claim 6, since the back yoke is disposed on the surface opposite to the surface facing the tilt coil of the tilt magnet, it is possible to improve the sensitivity of the movable block during tilt adjustment. .

  Further, the leakage magnetic flux from the tilt magnet is reduced, the second magnetic circuit is hardly affected by the first magnetic circuit, and the tilt of the movable block with respect to the fixed block due to the influence of the leakage magnetic flux can be prevented.

  The best mode 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 configured by arranging required members and mechanisms in an outer casing 2 (see FIG. 1), and the outer casing 2 has a disk insertion slot (not shown).

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

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

  The optical pickup 6 includes a moving base 7, required optical components provided on the moving base 7, and an objective lens driving device 8 disposed on the moving base 7, and is provided at both ends of the moving base 7. The bearing portions 7a and 7b are slidably supported by the guide shafts 4 and 4, respectively.

  When a nut member (not shown) provided on the moving base 7 is screwed into the lead screw 5 and the lead screw 5 is rotated by the feed motor, the nut member is sent in a direction corresponding to the rotation direction of the lead screw 5, The pickup 6 is moved in the radial direction of the disc-shaped recording medium 100 mounted on the disc table 3.

  The objective lens driving device 8 includes a base member 9, a fixed plate 10, a fixed block 11, and a movable block 12 operated with respect to the fixed block 11 (see FIGS. 2 and 3).

  The base member 9 is formed of a magnetic metal material, for example, SPCC (cold rolled steel plate), silicon steel plate or the like. As shown in FIG. 2, each of the base member 9a and the base portion 9a is fixed on the moving base 7. It consists of yoke portions 9b and 9b which are bent at a right angle. The yoke portions 9b and 9b are provided apart from each other in the front-rear direction, that is, in the tangential direction (TAN) of the disk-shaped recording medium 100.

  Magnets 13 and 13 are attached to the mutually opposing surfaces of the yoke portions 9b and 9b, respectively.

  The fixed plate 10 is provided apart from the base member 9 in the tangential direction (backward), and is fixed on the moving base 7. The fixed plate 10 is formed of a magnetic metal material, for example, SPCC (cold rolled steel plate), silicon steel plate, or the like. The plate base 10a is fixed on the moving base 7 and is bent from the front end of the plate base 10a. And tilt yokes 10b and 10b that are spaced apart in the radial direction (RAD) of the recording medium 100.

  The fixed block 11 is fixed on the plate base 10a of the fixed plate 10, and the rear surface of the fixed block 11 is provided with a total of four terminal portions 11a, 11a,... (See FIGS. 4 and 5).

  Terminal pins 11b and 11b projecting rearward from the rear surface are provided at the lower end portion of the fixed block 11 (see FIG. 4), and the terminal pins 11b and 11b are spaced apart from each other on the left and right.

  Positioning protrusions 11c and 11c protruding forward are provided on the front surface of the fixed block 11 so as to be spaced apart from each other (see FIG. 6).

  A relay substrate 14 is attached to the rear surface of the fixed block 11 (see FIG. 4). The relay board 14 includes a base portion 14a located at the center portion and four connection portions 14b, 14b,... Protruding left and right from the base portion 14a. In the relay substrate 14, the tip portions of the connection portions 14b, 14b,... Are connected to the terminal portions 11a, 11a,.

  A pair of tilt coils 16 and 16 are attached to the front surface of the fixed block 11 so as to be separated from each other in the radial direction of the disc-shaped recording medium 100 (see FIGS. 3 and 6). As shown in FIG. 6, the tilt coils 16 and 16 are attached to the fixed block 11 by being externally fitted to positioning protrusions 11 c and 11 c provided on the front surface of the fixed block 11. Therefore, by providing the positioning projections 11c and 11c on the fixed block 11, the tilt coils 16 and 16 can be easily positioned and attached to the fixed block 11.

  The tilt coils 16, 16 are formed in a substantially rectangular tube shape with a small thickness, and are attached to the fixed block 11 so that the winding axis direction is the front-rear direction, that is, the tangential direction. The tilt coils 16 and 16 are portions for causing the movable block 12 to generate a thrust force in the tilt direction, with the portions 16a, 16a,. Note that the tilt direction is the direction of surface deflection of the disk-shaped recording medium 100 (the R direction shown in FIG. 3), that is, the rotation direction about an axis extending in the tangential direction.

  One end of each of the tilt coils 16 and 16 is wound around and attached to terminal pins 11b and 11b provided on the rear surface of the fixed block 11 (see FIG. 4).

  A power supply board 17 connected to a power supply circuit (not shown) is attached to and connected to the relay board 14 attached to the rear surface of the fixed block 11 (see FIGS. 4 and 5). The power supply substrate 17 is, for example, a flexible printed wiring board, and includes four connection lines 17a, 17a,... And two connection lines 17b, 17b. The connection lines 17a, 17a,... Are connected to the connection portions 14b, 14b,... Of the relay board 14 by, for example, solders 18, 18,..., And the connection lines 17b, 17b are respectively terminal pins 11b. , 11b are connected to respective one end portions of the tilt coils 16 and 16 by solders 19 and 19, for example. Accordingly, the tilt coils 16 and 16 are supplied with a drive current for tilt adjustment from the power supply circuit via the connection lines 17 b and 17 b of the power feeding substrate 17.

  In this way, the power supply substrate 17 and the tilt coils 16 and 16 are connected by winding one end of each of the tilt coils 16 and 16 around the terminal pins 11b and 11b, and connecting each end of the tilt coils 16 and 16 and the connecting wire 17b, 17b is fixed by the solders 19 and 19, so that it can be easily performed, and the connection work between the power supply substrate 17 and the tilt coils 16 and 16 is simplified and the connection reliability is improved. Can do.

  At the position near the front end of the fixed block 11, yoke arrangement holes 11d and 11d extending vertically are formed (see FIGS. 6 and 7), and the yoke arrangement holes 11d and 11d are respectively tilted yokes 10b and 10b of the fixed plate 10. Are inserted and arranged from below. The tilt yokes 10b and 10b are positioned immediately behind the tilt coils 16 and 16, respectively (see FIG. 8).

  .. Are connected to the terminal portions 11a, 11a,... Of the fixed block 11, respectively (see FIGS. 3 and 4), and the support springs 20, 20,. .. are connected to the connection lines 17a, 17a,... Of the power supply substrate 17 through the terminal portions 11a, 11a,... And the connection portions 14b, 14b,. . The support springs 20, 20,... Protrude forward from the fixed block 11.

  The movable block 12 has a movable holder 21 and an objective lens 22 held by the movable holder 21 (see FIGS. 3 to 5).

  The movable holder 21 is formed by integrally forming a lens mounting portion 23 and a coil holding portion 24 provided on the rear side of the lens mounting portion 23.

  A transmission hole 23a penetrating vertically is formed in the lens attachment portion 23 (see FIG. 7), and the objective lens 22 is attached so as to cover the transmission hole 23a from above.

  The coil holding part 24 is formed in a substantially rectangular frame shape penetrating vertically, and a focusing coil 25 and tracking coils 26 and 26 are held inside the coil holding part 24.

  The focusing coil 25 is a coil for operating the movable block 12 in the focusing direction, that is, the direction in which the movable block 12 is separated from or contacting the disc-shaped recording medium 100 (the F direction shown in FIG. 3), and the tracking coils 26 and 26 track the movable block 12. It is a coil for operating in the direction, that is, the substantially radial direction of the disk-shaped recording medium 100 (T direction shown in FIG. 3).

  The focusing coil 25 and the tracking coils 26 and 26 are each formed by being wound in a substantially rectangular tube shape. The focusing coil 25 has a winding direction in the vertical direction (focusing direction), and the tracking coils 26 and 26 have a winding direction in the winding direction. The front-rear direction (tangential direction) is used. The tracking coils 26 and 26 are provided on the front surface of the focusing coil 25 so as to be separated from each other on the left and right.

  The end portions of the focusing coil 25 and the tracking coils 26 and 26 are connected to connection terminal portions 21a, 21a,... Provided on both side surfaces of the movable holder 21, respectively. The front end portions of the support springs 20, 20,... Are connected to the connection terminal portions 21a, 21a,. Therefore, the movable block 12 is connected to the fixed block 11 by the support springs 20, 20,.

  In the objective lens driving device 8, in the state where the movable block 12 is held hollow with respect to the fixed block 11 by the support springs 20, 20,. When the movable block 12 is operated in such a direction, as shown in FIG. 9, the movable block 12 is moved downward by its own weight, and the front ends of the support springs 20, 20,. It will be in the state bent so that it may be located. In the objective lens driving device 8, the position where the movable block 12 is moved downward by its own weight is set as a neutral position in the focusing direction of the movable block 12. Therefore, at the neutral position in the focusing direction, as shown in FIG. 9, the center in the vertical direction of the tilt magnets 29 and 29, that is, the neutral line M1 between the magnetic poles coincides with the center M2 in the vertical direction of the tilt coils 16 and 16. Has been.

  By setting the position in consideration of the weight of the movable block 12 to the neutral position in the focusing direction in this way, the change in the tilt characteristic accompanying the focusing operation of the movable block 12 becomes symmetric in the vertical direction. The reliability of the tilt operation can be achieved.

  When the objective lens driving device 8 is used in a state where the focusing direction is not up and down, for example, the driving current supplied to the focusing coil 25 with the focus servo applied to the movable block 12 is zero. May be set as a neutral position in the focusing direction of the movable block 12.

  Focusing adjustment is performed on the support springs 20, 20,... Via the connection lines 17 a, 17 a,... Of the power supply substrate 17 and the connection portions 14 b, 14 b,. Driving current for tracking or tracking adjustment is supplied. Therefore, two of each of the support springs 20, 20,... Function as power feeding members to the focusing coil 25 and the tracking coils 26, 26, respectively.

  Magnets 13 and 13 attached to the yoke portions 9b and 9b are disposed on the front portion of the focusing coil 25 and the front and rear sides of the tracking coils 26 and 26, respectively (see FIG. 8). By arranging the magnets 13 and 13 in this way, the magnets 13 and 13, the yoke portions 9 b and 9 b, the focusing coil 25 and the tracking coils 26 and 26 move the movable block 12 in the focusing direction or the tracking direction. A magnetic circuit 27 is configured.

  Back yokes 28 and 28 and tilt magnets 29 and 29 are attached to the rear surface portion of the coil holder 24 of the movable holder 21 so as to be separated from each other in the left-right direction (see FIGS. 2 and 3). As shown in FIG. 2, the tilt magnets 29 and 29 are two-pole magnetized so that the N poles 29a and 29a and the S poles 29b and 29b are separately located in the focusing direction.

  The tilt magnets 29 and 29 are respectively positioned to face the tilt coils 16 and 16 attached to the front surface of the fixed block 11 (see FIG. 8). As the tilt magnets 29 and 29 are positioned so as to face the tilt coils 16 and 16, the movable block 12 is formed by the tilt magnets 29 and 29, the back yokes 28 and 28, the tilt coils 16 and 16, and the tilt yokes 10b and 10b. Is configured to operate in the tilt direction.

  When a drive current is supplied from the power supply circuit to the focusing coil 25 or the tracking coils 26, 26 via the power supply substrate 17, the relay substrate 14, and the support springs 20, 20,. The movable block 12 is moved in the focusing direction (F direction shown in FIG. 3) or the tracking direction (T direction shown in FIG. 3) depending on the relationship with the direction of the magnetic flux generated by 13, 13 and the yoke portions 9b, 9b.

  When a drive current is supplied from the power supply circuit to the tilt coils 16 and 16 via the power supply substrate 17, the direction of these drive currents and the back yokes 28 and 28, the tilt magnets 29 and 29, and the tilt yokes 10b and 10b are used. The movable block 12 is moved in the tilt direction (R direction shown in FIG. 3) depending on the relationship with the direction of the generated magnetic flux. In the tilt adjustment, when a drive current is supplied to the tilt coils 16 and 16, thrust generated in the movable block 12 is generated on the opposite side (up and down) on the left side and the right side, and the movable block 12 is moved in the tilt direction. Is done.

  When the movable block 12 is moved in the focusing direction, tracking direction, or tilt direction, the support springs 20, 20,... Are elastically deformed.

  A raising mirror 31 is disposed below the objective lens 22 provided in the movable holder 21 (see FIG. 9).

  In the disk drive device 1 configured as described above, when the disk table 3 is rotated in accordance with the rotation of the spindle motor, the disk-shaped recording medium 100 mounted on the disk table 3 is rotated, and at the same time, the light The pickup 6 is moved in the radial direction of the disc-shaped recording medium 100, and a recording operation or a reproducing operation is performed on the disc-shaped recording medium 100.

  In this recording operation and reproduction operation, when a driving current is supplied to the focusing coil 25, the movable block 12 of the objective lens driving device 8 is in the focusing direction FF shown in FIG. So that the spot of the laser light emitted from a light source (not shown) provided on the moving base 7 and irradiated through the objective lens 22 is condensed substantially vertically corresponding to the warp of the disc-shaped recording medium 100. Focusing adjustment is made.

  When a drive current is supplied to the tracking coils 26, 26, as described above, the movable block 12 of the objective lens driving device 8 is operated in the tracking direction TT shown in the figure with respect to the fixed block 11, and the light source Tracking adjustment is performed so that the spot of the laser beam emitted from the laser beam and irradiated through the objective lens 22 is condensed on the recording track of the disc-shaped recording medium 100.

  Further, when a drive current is supplied to the tilt coils 16 and 16, as described above, the movable block 12 of the objective lens driving device 8 is operated in the tilt direction RR shown in FIG. Tilt adjustment is performed so that the spot of the laser beam emitted from the light source and irradiated through the objective lens 22 is condensed on the recording track of the disc-shaped recording medium 100.

  As described above, the optical pickup 6 is provided with the tilt magnets 29 and 29 that are two-pole magnetized so that the N poles 29a and 29a and the S poles 29b and 29b are located in the focusing direction. Since the coils 16 and 16 are arranged so that the winding axis direction is the tangential direction, about half of the entire portion of the tilt coils 16 and 16 is tilted to the movable block 12. It can be used as a portion for generating a thrust in the direction, and the sensitivity of the movable block 12 at the time of tilt adjustment can be improved.

  In addition, since the sensitivity of the movable block 12 can be improved, it is not necessary to use a magnet having a strong magnetic force, and it is not necessary to supply a high driving current to the tilt coils 16 and 16, and the objective lens driving device 8 can reduce the manufacturing cost and the power consumption.

  Further, since the winding axis direction of the tilt coils 16 and 16 is not the focusing direction, the arrangement space of the tilt coils 16 and 16 in the tangential direction is small, and the size of the objective lens driving device 8 in the tangential direction is reduced. be able to.

  Furthermore, in the objective lens driving device 8, the objective lens 22 and the second magnetic circuit for tilt adjustment are arranged on the opposite side in the tangential direction across the first magnetic circuit 27 for focusing adjustment and tracking adjustment. Therefore, the raising mirror 31 can be arranged at the same height as the first magnetic circuit 27, and the objective lens driving device 8 can be made thinner accordingly. Can do. Such thinning is particularly suitable for an optical pickup used in a portable device.

  In the objective lens driving device 8, since the tilt magnets 29 and 29 are provided in the movable block 12 and the tilt coils 16 and 16 are provided in the fixed block 11, a support spring for supplying power to the tilt coils 16 and 16 is provided. Therefore, it is possible to reduce the number of parts and simplify the assembling of the objective lens driving device 8 accordingly.

  In addition, in the objective lens driving device 8, since the tilt yokes 10b and 10b are provided by bending a part of the fixed plate 10 for fixing the fixed block 11, it is necessary to provide a dedicated tilt coil. In addition, the plate base 10a and the tilt yokes 10b and 10b, which are parts for fixing the fixing block 11, can be shared, and the number of parts can be reduced.

  In the objective lens driving device 8, the back yokes 28, 28 are arranged on the surface of the tilt magnets 29, 29 opposite to the surface facing the tilt coils 16, 16.

  Accordingly, it is possible to improve the sensitivity of the movable block 12 at the time of tilt adjustment.

  If the back yokes 28 are not provided, as shown in FIG. 10, for example, the upper part of the tilt magnet 29 is attracted to the first magnetic circuit 27 side due to the relationship of the direction of the magnetic force generated in each part. Since the lower portion of the tilt magnet 29 repels the first magnetic circuit 27, a downward moving force P is generated in the tilt magnet 29, and the movable block 12 is moved downward, which adversely affects the focusing operation. There is a risk.

  Further, the objective lens driving device 8 is provided with a pair of tilt magnets 29 and 29 and tilt coils 16 and 16 spaced apart in the tracking direction (T direction shown in FIG. 11), and the movable block 12 is tracking. Since the positional relationship between the tilt magnets 29 and 29 and the first magnetic circuit 27 changes when moved in the tracking direction by the operation, the tilt magnets 29 and 29 are affected by the first magnetic circuit 27 as described above. In the case of receiving, the downward moving force generated in the tilt magnets 29 and 29 is different between right and left, and the movable block 12 is inclined in the R direction shown in FIG. 11 and applied to the disc-shaped recording medium 100 via the objective lens 22. There is a possibility that the optical axis of the irradiated laser beam is inclined.

  Further, in the objective lens driving device 8, when the spring forces of the support springs 20, 20,... Are different on the left and right due to manufacturing errors or the like, generally, the inclination of the movable block 12 in the R direction during the focusing operation is generally reduced. The position of the base member 9 is adjusted in the tracking direction so as to be optimal (zero). In this case as well, the positional relationship between the tilt magnets 29 and 29 and the first magnetic circuit 27 changes as described above. Further, the downward moving force generated in the tilt magnets 29 and 29 is different on the left and right, and the movable block 12 may be inclined in the R direction shown in FIG.

  However, in the objective lens driving device 8, as described above, the back yokes 28, 28 are disposed on the surface opposite to the surface facing the tilt coils 16, 16 of the tilt magnets 29, 29. As shown in FIG. 12, the leakage magnetic flux from the tilt magnets 29, 29 is reduced, and the second magnetic circuit 30 is hardly affected by the first magnetic circuit 27, so that the movable block 12 is moved in the R direction as described above. Can be prevented.

  The objective lens driving device 8 may be configured not to have the back yokes 28, 28. In this case, the objective lens driving device 8 is directed to the base member 9 side (lower side) generated in the tilt magnets 29, 29 as described above. The objective lens 22 can be held away from the disk-shaped recording medium 100 in a non-use state in which no driving current is supplied to the focusing coil 25 by using the moving force of the movable block 12 regardless of the use posture of the movable block 12. The contact between the disc-shaped recording medium 100 and the objective lens 22 can be prevented.

  In the above description, the focusing direction is the vertical direction, and the tracking direction is the left-right direction. However, these directions are shown as examples for convenience of explanation, and are not particularly limited to these directions.

  The specific shapes and structures of the respective parts shown in the best mode for carrying out the invention described above are merely examples of the implementation of the present invention, and the present invention is thereby limited. This technical scope should not be interpreted in a limited way.

2 to 12 show the best mode for carrying out the present invention, and this figure is a schematic perspective view of a disk drive device. FIG. It is an expansion perspective view which decomposes | disassembles and shows a part of objective lens drive device. It is an expansion perspective view of an objective lens drive device. It is an enlarged perspective view which removes the electric power feeding board | substrate and shows an objective lens drive device. It is an expansion perspective view which shows the state which looked at the objective lens drive device from the direction different from FIG. It is an expansion disassembled perspective view which shows a fixed block. FIG. 6 is an enlarged perspective view illustrating a state in which a part of the objective lens driving device is omitted and viewed from a direction different from FIGS. 3 and 5. It is an expansion perspective view which shows a 1st magnetic circuit and a 2nd magnetic circuit. It is a general | schematic enlarged side view which shows an objective lens drive device. It is a conceptual diagram which shows the direction of the magnetic force when the back yoke is not provided. It is a conceptual diagram for demonstrating the operation | movement which may occur when the back yoke is not provided. It is a conceptual diagram which shows the direction of the magnetic force in case the back yoke is provided.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Disc-shaped recording medium, 1 ... Disc drive apparatus, 3 ... Disc table, 6 ... Optical pick-up, 7 ... Moving base, 8 ... Objective lens drive device, 10 ... Fixed plate, 10b ... Tilt yoke, 11 ... Fixed block, 12 ... movable block, 16 ... tilt coil, 20 ... support spring, 22 ... objective lens, 27 ... first magnetic circuit, 28 ... back yoke, 29 ... tilt magnet, 29a ... N pole, 29b ... S pole, 30 ... first 2 magnetic circuit

Claims (6)

An optical pickup comprising a moving base moved in the radial direction of a disk-shaped recording medium mounted on a disk table, and an objective lens driving device arranged on the moving base,
The objective lens driving device is:
A fixed plate provided on the moving base;
A fixed block disposed on the fixed plate and fixed to the moving base;
Holds the objective lens and is orthogonal to the focusing direction, which is the direction in which the fixed block is separated from or contacting the recording surface of the disk-shaped recording medium, the tracking direction, which is the substantially radial direction of the disk-shaped recording medium, and the radial direction of the disk-shaped recording medium A movable block that is operated in a tilt direction that is a direction around an axis extending in a tangential direction that is a tangential direction of the disk-shaped recording medium;
A plurality of support springs that movably support the movable block with respect to the fixed block;
A first magnetic circuit for moving the movable block in the focusing direction or the tracking direction;
A second magnetic circuit for moving the movable block in the tilt direction,
The second magnetic circuit has a pair of tilt magnets magnetized so that the N pole and the S pole are positioned in the focusing direction and spaced apart from each other in the radial direction. A pair of tilt coils that are arranged and the winding axis direction is the tangential direction;
A pair of tilt magnets are provided on the movable block,
A pair of tilt coils is provided on the fixed block,
An optical pickup characterized in that an objective lens and a second magnetic circuit are positioned on opposite sides in the tangential direction across the first magnetic circuit. 2. The optical pickup according to claim 1, wherein a tilt yoke disposed on the opposite side of the tilt magnet in the tangential direction with a tilt coil sandwiched between a part of the fixed plate is provided. The optical pickup according to claim 1, wherein a back yoke is disposed on a surface opposite to a surface facing the tilt coil of the tilt magnet. A disk table on which a disk-shaped recording medium is mounted; and an optical pickup that irradiates a laser beam on the disk-shaped recording medium mounted on the disk table via an objective lens. The optical pickup is mounted on the disk table. A disk drive device having a moving base moved in the radial direction of the disk-shaped recording medium and an objective lens driving device arranged on the moving base,
The objective lens driving device is:
A fixed plate provided on the moving base;
A fixed block disposed on the fixed plate and fixed to the moving base;
Holds the objective lens and is orthogonal to the focusing direction, which is the direction in which the fixed block is separated from or contacting the recording surface of the disk-shaped recording medium, the tracking direction, which is the substantially radial direction of the disk-shaped recording medium, A movable block that is operated in a tilt direction that is a direction around an axis extending in a tangential direction that is a tangential direction of the disk-shaped recording medium;
A plurality of support springs that movably support the movable block with respect to the fixed block;
A first magnetic circuit for moving the movable block in the focusing direction or the tracking direction;
A second magnetic circuit for moving the movable block in the tilt direction,
The second magnetic circuit has a pair of tilt magnets magnetized so that the N pole and the S pole are positioned in the focusing direction and are spaced apart from each other in the radial direction. A pair of tilt coils that are arranged and the winding axis direction is the tangential direction;
A pair of tilt magnets are provided on the movable block,
A pair of tilt coils is provided on the fixed block,
An objective lens and a second magnetic circuit are positioned on opposite sides in the tangential direction across the first magnetic circuit. 5. The disk drive device according to claim 4, further comprising a tilt yoke disposed on the opposite side of the tilt magnet in the tangential direction with a part of the fixed plate bent and sandwiched between the tilt coils. The disk drive device according to claim 4, wherein a back yoke is disposed on a surface opposite to a surface facing the tilt coil of the tilt magnet.

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