JP2005302162A - Optical pickup and diskdrive apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make design easy and to improve reliability in operation control of an objective lens drive apparatus. <P>SOLUTION: The objective drive apparatus 8 is provided with a fixed block 10 fixed to a movement base 7, a movable block 11 operated in the focusing direction, the tracking direction, and the tilt direction, and holding two objective lenses 18, 19, and supporting springs 1, 15 coupling the fixed block and the movable block, the movable block is provided with a pair of coil bodies 17, 17 energized at the time of operation of the movable block in the focusing direction, the tracking direction, or the tilt direction and divided in the radial direction holding the objective lens between them and arranged, a lens center P of one side of the objective lenses is positioned corresponding to a first line segment Lr extended to the radial direction through a rotary center of a disk table 3, a lens center Q of the other side of the objective lenses is positioned at a position being deviated from the first line segment and at a position of the disk table side more than a second line segment Lt extended to the tangential direction and passing through the lens center of one side of the objective lenses. <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 and a magneto-optical disk. Such a disk drive apparatus moves in the radial direction of the disk-shaped recording medium and moves the disk An optical pickup for irradiating the recording medium with 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 and 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 tilt adjustment can be performed when the disk-shaped recording medium is rotating. Further, an objective lens driving device called a so-called triaxial actuator has been developed.

  On the other hand, various types of disc-shaped recording media have been developed in recent years due to differences in recording density, cover thickness, and the like. (Compact Disc), DVD (Digital Versatile Disc) whose use wavelength is around 660 nm, Blu-ray disc (BD) whose use wavelength is around 405 nm, AOD (Advanced Optical Disc) whose use wavelength is around 405 nm, etc. Exists. An HD-DVD (High Definition DVD) is a standard that is substantially compliant with the AOD standard.

  As an optical pickup for recording and reproducing information signals to and from a plurality of types of disc-shaped recording media having different wavelengths used for such laser light, one having two objective lenses corresponding to the plurality of disc-shaped recording media (For example, refer to Patent Document 1).

  In the optical pickup described in Patent Document 1, for example, an objective lens having two objective lenses corresponding to a disk-shaped recording medium using about 660 nm laser light and a disk-shaped recording medium using about 780 nm laser light. A driving device is provided, and a laser beam of about 780 nm is condensed on the recording surface of one disk-shaped recording medium by one objective lens, and a laser beam of about 660 nm is recorded on the other disk-shaped recording medium by the other objective lens. Information is recorded on and reproduced from each disk-shaped recording medium by focusing on the surface.

  In such an optical pickup having two objective lenses, as shown in FIG. 6, the rotation center of the disk table b extends in the moving direction of the optical pickup a, that is, in the radial direction (RAD) of the disk-shaped recording medium. When the center of one objective lens e provided in the movable block d of the objective lens driving device c is aligned on the line segment L passing through S, the other objective lens f is in the tangential direction (TAN), that is, the disk. It is arranged at a position separated from one objective lens e in the tangential direction of the recording track of the recording medium. At this time, if the position at which the information recorded on the innermost circumference of the disc-shaped recording medium is read by one objective lens e is set at the inner moving end in the moving direction of the optical pickup a, the other objective lens f Information recorded on the innermost circumference of the disc-shaped recording medium cannot be read.

  Therefore, it is necessary to set the position for reading the information recorded on the innermost circumference of the disk-shaped recording medium by the other objective lens f at the inner moving end in the moving direction of the optical pickup a. In order to avoid contact between the pickup a and the disk table b or the spindle motor for driving the pickup table, a means such as recessing a part of the disk table b or the spindle motor is required, which makes it difficult to design a disk drive device. As a result, there arises a problem that the manufacturing cost increases.

  Therefore, as shown in FIG. 7, in the optical pickup g described in Patent Document 1, the objective lens driving device h is disposed obliquely with respect to the tangential direction, and one of the ones provided in the movable block i is provided. While the center of the objective lens j is positioned on the line segment L, the other objective lens k is brought close to the disk table b.

  By disposing the objective lens driving device h obliquely with respect to the tangential direction in this way, when the optical pickup g is moved to the inner moving end, the innermost of the disc-shaped recording medium is moved by one objective lens j. The information recorded on the circumference can be read and the information recorded on the innermost circumference of the disc-shaped recording medium can be read by the other objective lens k.

JP-A-11-250479

  However, in the optical pickup g described in Patent Document 1, the objective lens driving device h is disposed obliquely with respect to the tangential direction so as to avoid problems such as design difficulties. However, since the objective lens driving device h is disposed obliquely, the operation direction of the movable block i during tracking adjustment is shifted from the radial direction of the disk-shaped recording medium (A shown in FIG. 7). -A direction).

  Accordingly, in tracking error detection using a side beam such as the three-beam method, signal level fluctuations due to changes in the phase difference between the inner and outer circumferences of the disk-shaped recording medium are large, and the tracking operation may be adversely affected.

  In addition to focusing adjustment and tracking adjustment, as described above, when tilt adjustment is performed to move the movable block in the tilt direction, the objective lens drive device is arranged so as to be inclined with respect to the tangential direction. The direction of the tilting operation of the block and the displacement direction due to the surface shake of the disk-shaped recording medium do not coincide with each other, which may adversely affect the operation during tilt adjustment.

  Accordingly, an object of the optical pickup and the disk drive device of the present invention is to overcome the above-described problems, and to improve the reliability of the design control and the operation control 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 block fixed to a moving base and a recording surface of a disk-shaped recording medium with respect to the fixed block. A focusing direction that is a contact direction, a tracking direction that is a substantially radial direction of the disk-shaped recording medium, and a direction around an axis extending in a tangential direction that is perpendicular to the radial direction of the disk-shaped recording medium and that is a tangential direction of the disk-shaped recording medium The movable block that is operated in the tilt direction and holds the two objective lenses, and the support spring that connects the fixed block and the movable block are provided, and the focusing direction, tracking direction, or tilt of the movable block is provided on the movable block. Energized when operating in the direction and the objective lens A pair of coil bodies arranged in a radial direction are provided, and the lens center of one objective lens is positioned corresponding to the first line segment extending in the radial direction through the rotation center of the disk table, The other objective lens is positioned on the disc table side with respect to the second line segment extending from the first line segment and extending in the tangential direction and passing through the lens center of the one objective lens. It is a thing.

  Therefore, in the optical pickup and the disk drive device of the present invention, the line segment connecting the lens centers of the two objective lenses is inclined with respect to the tangential direction, and the movable block is moved in the substantially radial direction during tracking adjustment. The

  The optical pickup of the present invention includes a moving base that is moved in the radial direction of a disk-shaped recording medium that is mounted on the disk table, and an objective lens driving device that is disposed on the moving base, and has an operating wavelength mounted on the disk table. An optical pickup that irradiates laser light of three types corresponding to different disc-shaped recording media, the objective lens driving device comprising: a fixed block fixed to the moving base; and A focusing direction which is a direction in which the recording surface of the disk-shaped recording medium is separated from, a tracking direction which is a substantially radial direction of the disk-shaped recording medium, and a tanger which is perpendicular to the radial direction of the disk-shaped recording medium and which is a tangential direction of the disk-shaped recording medium Two objective lenses that are operated in the tilt direction, which is the direction around the axis extending in the local direction A movable block for holding, and a support spring for connecting the fixed block and the movable block. The movable block is energized when the movable block is operated in a focusing direction, a tracking direction, or a tilt direction, and the objective lens is And a pair of coil bodies arranged in the radial direction with the objective lens on one side corresponding to the first line segment extending in the radial direction through the center of rotation of the disk table. The objective lens of the other objective lens has a lens center deviated from the first line segment, and extends in the tangential direction from the second line segment passing through the lens center of the one objective lens. It is characterized by being positioned on the side.

  Therefore, the information signal recorded on the innermost circumference of each disk-shaped recording medium can be read by each of the two objective lenses without designing a part of the disk table or spindle motor to be recessed. .

  Also, since the objective lens driving device is not arranged obliquely with respect to the tangential direction, the direction in which the movable block moves during tracking adjustment coincides with the radial direction of the disk-shaped recording medium, and the movable block moves during tilt adjustment. The direction to be matched coincides with the direction following the surface shake of the disc-shaped recording medium, and the control operation can be optimized and the operation reliability can be improved during tracking adjustment and tilt adjustment.

  Further, since the lens center of one objective lens is positioned on the first line segment passing through the rotation center of the disc table, in a disc-shaped recording medium for recording and reproducing information signals using the first objective lens The tracking error signal can be read using a so-called three-beam method or a differential push-pull method.

  According to the second aspect of the present invention, the two objective lenses have different weights, and the magnetic circuit tanger includes a magnet, a yoke, and a coil body on the movable block arranged on the moving base. The center of gravity of the entire movable block is set to the magnetic position because the distance between the center of the two objective lenses is closer to the center of the two objective lenses than the objective lens with a large weight. It is possible to reduce the additional weight when matching with the approximate center position of the circuit, and the sensitivity of the objective lens driving device can be increased.

  In the invention described in claim 3, the coil body includes a focusing coil for operating the movable block in the focusing direction, a tracking coil for operating the movable block in the tracking direction, and a tilting direction of the movable block. Since the focusing coil and the tilt coil are arranged in the focusing direction, the space for arranging the focusing coil and the tilt coil can be reduced, and the optical pickup can be made smaller and thinner. Can be achieved.

  In the invention described in claim 4, the coil body is constituted by a common coil for operating the movable block in the focusing direction and the tilt direction and a tracking coil for operating the movable block in the tracking direction. Therefore, the number of parts of the optical pickup can be reduced and the manufacturing cost can be reduced.

  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 has a moving base moved in the radial direction of a disk-shaped recording medium mounted on the disk table, and an objective lens driving device arranged on the moving base, and each disk-shaped mounted on the disk table has a different use wavelength. A disk drive device configured to irradiate laser beams of three types of wavelengths corresponding to a recording medium, wherein the objective lens driving device includes a fixed block fixed to the moving base, and a fixed block On the other hand, the focusing direction, the direction in which the recording surface of the disc-shaped recording medium is separated from and contacting The tracking direction, which is a substantially radial direction of the disk-shaped recording medium, and the tilt direction, which is the direction around the axis extending in the tangential direction perpendicular to the radial direction of the disk-shaped recording medium and tangential to the disk-shaped recording medium. And a support block for connecting the fixed block and the movable block, and the movable block is energized when the movable block is operated in the focusing direction, tracking direction or tilt direction. And a pair of coil bodies that are divided and arranged in the radial direction with the objective lens interposed therebetween, and one objective lens has a lens center extending in the radial direction through the rotation center of the disk table. The other objective lens is positioned correspondingly on one line segment, and the center of the lens deviates from the first line segment. Location, and is characterized in that so as to be positioned on the disc table side of the second line segment that passes through the lens center of the one of the objective lens extends the tangential direction.

  Therefore, the information signal recorded on the innermost circumference of each disk-shaped recording medium can be read by each of the two objective lenses without designing a part of the disk table or spindle motor to be recessed. .

  Also, since the objective lens driving device is not arranged obliquely with respect to the tangential direction, the direction in which the movable block moves during tracking adjustment coincides with the radial direction of the disk-shaped recording medium, and the movable block moves during tilt adjustment. The direction to be matched coincides with the direction following the surface shake of the disc-shaped recording medium, and the control operation can be optimized and the operation reliability can be improved during tracking adjustment and tilt adjustment.

  Further, since the lens center of one objective lens is positioned on the first line segment passing through the rotation center of the disc table, in a disc-shaped recording medium for recording and reproducing information signals using the first objective lens The tracking error signal can be read using a so-called three-beam method or a differential push-pull method.

  In the invention described in claim 6, the tanger of the magnetic circuit is configured such that the weights of the two objective lenses are different, and the magnet, the yoke, and the coil body on the movable block are arranged on the moving base. The center of gravity of the entire movable block is set to the magnetic position because the distance between the center of the two objective lenses is closer to the center of the two objective lenses than the objective lens with a large weight. It is possible to reduce the additional weight when matching with the approximate center position of the circuit, and the sensitivity of the objective lens driving device can be increased.

  In the invention described in claim 7, the coil body includes a focusing coil for operating the movable block in the focusing direction, a tracking coil for operating the movable block in the tracking direction, and the movable block in the tilt direction. Since the focusing coil and the tilt coil are arranged in the focusing direction, the space for arranging the focusing coil and the tilt coil can be reduced, and the disk drive device can be made smaller and thinner. Can be achieved.

  In the invention described in claim 8, the coil body is constituted by a common coil for operating the movable block in the focusing direction and the tilt direction and a tracking coil for operating the movable block in the tracking direction. Therefore, it is possible to reduce the number of parts and the manufacturing cost of the disk drive device.

  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.

  As the disc-shaped recording medium 100, for example, in addition to a DVD (Digital Versatile Disc) 100a and a CD (Compact Disc) 100b, a Blu-ray disc (BD) 100c or an AOD (Advanced Optical Disc) 100d is used. The operating wavelengths of the laser light of each of these disk-shaped recording media 100 are about 660 nm for DVD 100a, about 780 nm for CD 100b, and about 405 nm for BD 100c and AOD 100d.

  The cover thickness of each disk-shaped recording medium 100 is 0.6 mm for DVD 100a, 1.2 mm for CD 100b, 0.1 mm for BD 100c, and 0.6 mm for AOD 100d.

  The numerical aperture of an objective lens (described later) provided in the objective lens driving device 8 is about 0.5 for the CD 100b and 0.65 for the DVD 100a and the AOD 100d in consideration of the wavelength used and the cover thickness of each disk-shaped recording medium 100. The BD 100c is desirably about 0.85.

  The objective lens driving device 8 includes a base member 9, a fixed block 10, and a movable block 11 operated with respect to the fixed block 10 (see FIGS. 2 to 5).

  The base member 9 is made of a magnetic metal material, and includes a base portion 9a mounted on the movable base 7, and outer yoke portions 9b and 9b and inner yoke portions 9c and 9c that are bent at right angles from the base portion 9a. (See FIG. 2). The outer yoke portions 9b and 9b are spaced apart in the front-rear direction, that is, in the tangential direction of the disc-shaped recording medium 100, and the inner yoke portions 9c and 9c are separated in the left-right direction, that is, in the radial direction of the disc-shaped recording medium 100. Is provided.

  Two magnets 12, 12,... Are attached to the surfaces of the outer yoke portions 9b, 9b facing each other (see FIGS. 2 and 3). The magnets 12, 12,... Are attached to the left and right ends of the outer yoke portions 9b, 9b.

  The fixed block 10 is fixed to the moving base 7. On the rear surface of the fixed block 10, a total of six terminal portions 13, 13,... 2 shows only two terminal portions.).

  One end of a circuit board 14 is attached to the rear surface of the fixed block 10, and the circuit board 14 is connected to a power circuit (not shown). The circuit board 14 is, for example, a flexible printed wiring board, and one end of each connection line is connected to terminal portions 13, 13,.

  Each of the rear end portions of the support springs 15, 15,... (Only two support springs are shown in FIG. 2) is connected to the terminal portions 13, 13,. , 15,... Are connected to each connection line of the circuit board 14 through terminal portions 13, 13,. The support springs 15, 15,... Protrude forward from the fixed block 10.

  The movable block 11 includes a lens mounting portion 16 and a pair of coil bodies 17 and 17.

  Two transmission holes (not shown) penetrating vertically are formed in the lens mounting portion 16, and the first objective lens 18 and the second objective lens 19 are mounted so as to cover the transmission holes from above. .

  The first objective lens 18 has a configuration corresponding to, for example, about 660 nm and about 780 nm laser light, and has a numerical aperture of about 0.65 and about 0.5, respectively. The second objective lens 19 has a configuration corresponding to, for example, about 405 nm laser light, and has a numerical aperture of about 0.85. As described above, the second objective lens 19 has a numerical aperture larger than that of the first objective lens 18, and is accordingly thicker and heavier than the first objective lens 18.

  The second objective lens 19 is disposed closer to the fixed block 10 than the first objective lens 18. As shown in FIG. 4, the lens center P of the first objective lens 18 extends in the moving direction of the optical pickup 6, that is, in the radial direction of the disk-shaped recording medium 100, and passes through the rotation center S of the disk table 3. It is located corresponding to the line segment Lr. The lens center Q of the second objective lens 19 is positioned closer to the disc table 3 than the second line segment Lt extending in the tangential direction of the disc-shaped recording medium 100 and passing through the lens center P of the first objective lens 18. Preferably, in a state where the disc-shaped recording medium 100 is mounted on the disc table 3, the lens center Q of the second objective lens 19 is a recording track Mt positioned directly above the lens center P of the first objective lens 18. (FIG. 4 shows a state in which the lens center Q is directly below the recording track Mt).

  The coil bodies 17 and 17 are respectively attached to the left and right side surfaces of the lens attachment portion 16 (see FIG. 2).

  As shown in FIG. 3, the coil body 17 includes a focusing coil 20 for operating the movable block 11 in the focusing direction, tracking coils 21 and 21 for operating the movable block 11 in the tracking direction, and the movable block 11. The tilt coil 22 is configured to operate in the tilt direction. The focusing direction is the direction in which the disc-shaped recording medium 100 is moved away from and contacting (F direction shown in FIG. 4), that is, the vertical direction, and the tracking direction is the radial direction of the disc-shaped recording medium 100 (T direction shown in FIG. 4). The tilt direction is the left-right direction, and the tilt direction is the direction of surface deflection of the disc-shaped recording medium 100 (the R direction shown in FIG. 4), that is, the rotation direction about the axis extending in the tangential direction.

  The focusing coil 20, the tracking coils 21, 21 and the tilt coil 22 are each formed by being wound in a substantially rectangular tube shape, and the focusing coil 20 and the tilt coil 22 are each configured such that the winding axis direction is the vertical direction (focusing direction). The coils 21 and 21 have a winding axis direction as a front-rear direction (tangential direction).

  The focusing coil 20 and the tilt coil 22 are disposed so as to be stacked one above the other, and the tracking coils 21 and 21 are respectively attached to the front and rear surfaces of the focusing coil 20 and the tilt coil 22.

  The focusing coils 20 and 20 and the tilt coils 22 and 22 are magnets 12 and 12 having portions 20a, 20a,..., 22a, 22a,. The tracking coils 21, 21,... Are located on the inner side, that is, the portions 21 a, 21 a,. It is located opposite to. Therefore, of the focusing coils 20, 20, the tilt coil 22, and the tracking coils 21, 21,..., The portions 20a, 20a,. , 22a, 22a,..., 21a, 21a,... Are portions for applying thrust to the movable block 11 in the focusing direction, tracking direction, or tilt direction.

  The inner yoke portions 9c and 9c of the base member 9 are inserted and arranged in the focusing coils 20 and 20 and the tilt coils 22 and 22, respectively.

  The focusing coils 20, 20, the tracking coils 21, 21,... And the tilt coils 22, 22 are respectively connected to connecting terminal portions 23, 23 provided on both side surfaces of the lens mounting portion 20 of the movable holder 18. ···It is connected to the. The front end portions of the support springs 15, 15,... Are connected to the connection terminal portions 23, 23,. Therefore, the movable block 11 is connected to the fixed block 10 by the support springs 15, 15,.

  A driving current for focusing adjustment, tracking adjustment, or tilt adjustment is supplied to the support springs 15, 15... Via the circuit board 14 from the power supply circuit. Therefore, two of each of the support springs 15, 15,... Function as power feeding members to the focusing coils 20, 20, the tracking coils 21, 21,.

  When the driving current is supplied from the power supply circuit to the focusing coils 20, 20, tracking coils 21, 21,... Or tilt coils 22, 22 through the circuit board 14 and the support springs 15, 15,. The movable block 11 is moved in the focusing direction, tracking direction or tilt direction depending on the direction of the drive current and the direction of the magnetic flux generated by the magnets 12, 12,..., The outer yokes 9b, 9b and the inner yokes 9c, 9c. The

  When the movable block 11 is moved in the focusing direction, tracking direction, or tilt direction, the support springs 15, 15,... Are elastically deformed.

  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 reproducing operation, when a driving current is supplied to the focusing coil 20, the movable block 11 of the objective lens driving device 8 is in the focusing direction FF shown in FIG. The spot of the laser beam emitted from a semiconductor laser (not shown) provided on the moving base 7 and irradiated through the first objective lens 18 or the second objective lens 19 is warped of the disc-shaped recording medium 100. Correspondingly, focusing adjustment is performed so that light is condensed substantially vertically.

  When the driving current is supplied to the tracking coils 21, 21,..., The movable block 11 of the objective lens driving device 8 is moved in the tracking direction TT shown in FIG. Tracking adjustment so that the spot of the laser beam emitted from the semiconductor laser and irradiated through the first objective lens 18 or the second objective lens 19 is condensed on the recording track of the disc-shaped recording medium 100. Is done.

  Further, when a drive current is supplied to the tilt coils 22, 22, as described above, the movable block 11 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 semiconductor laser and irradiated through the first objective lens 18 or the second objective lens 19 is condensed on the recording track of the disc-shaped recording medium 100. .

  In the recording operation and the reproducing operation, the optical pickup 6 is moved from the inner circumference side to the outer circumference side of the disc-shaped recording medium 100. When the optical pickup 6 is moved to the moving end on the inner circumference side of the disc-shaped recording medium 100, when the disc-shaped recording medium 100 mounted on the disc table 3 is a DVD 100a or a CD 100b, the first objective lens 18 is used. The lens center P is located corresponding to the innermost recording track. On the other hand, when the optical pickup 6 is moved to the moving end on the inner peripheral side of the disc-shaped recording medium 100, when the disc-shaped recording medium 100 mounted on the disc table 3 is the BD 100c or the AOD 100d, as described above, The lens center Q of the second objective lens 19 is located closer to the disc table 3 than the second line segment Lt passing through the lens center P of the first objective lens 18, and the lens center Q is at the outermost position of the BD 100 c or AOD 100 d. It is located corresponding to the recording track on the inner circumference.

  As described above, in the optical pickup 6, the first line segment Lr, in which the lens center P of the first objective lens 18 passes through the rotation center S of the disk table 3 and extends in the radial direction of the disk-shaped recording medium 100. Since the lens center Q of the second objective lens 19 is positioned on the disk table 3 side with respect to the second line segment Lt extending in the tangential direction and passing through the lens center P, the disk table 3 and the spindle motor The information signal recorded on the innermost circumference of each disk-shaped recording medium 100 can be read by the first objective lens 18 and the second objective lens 19 without designing such that a part of the recording medium is recessed. it can.

  In addition, since the objective lens driving device 8 is not disposed obliquely with respect to the tangential direction, the direction in which the movable block 11 is moved during tracking adjustment coincides with the radial direction of the disk-shaped recording medium 100 and is movable during tilt adjustment. The direction in which the block 11 is moved coincides with the direction in which the disc-shaped recording medium 100 follows the surface deflection, etc., so that the control operation can be optimized and the operation reliability can be improved during tracking adjustment and tilt adjustment. .

  Further, since the lens center P of the first objective lens 18 is positioned on the first line segment Lr passing through the rotation center S of the disk table 3, the information signal is recorded and reproduced using the first objective lens 18. In the disk-shaped recording medium 100 that performs the above, the tracking error signal can be read using a so-called three-beam method or a differential push-pull method. In the disk-shaped recording medium 100 that records and reproduces information signals using the second objective lens 19, the tracking error signal may be read by a method using one beam.

  Furthermore, in the objective lens driving device 8, the second objective lens 19 having a large weight is placed on the moving base 7 by the magnets 12, 12,..., The outer yoke from the first objective lens 18 having a small weight. The centers of the two objective lenses 18 and 19 with respect to the approximate center position in the tangential direction of the magnetic circuit composed of the coil portions 17 and 17 on the movable block 11 and the coil portions 17 and 17 on the movable blocks 11 and 9b and 9b. Since the second objective lens 19 having a large weight is disposed closer to the first objective lens 18 having a small weight, the position of the center of gravity of the entire movable block 11 is set to the approximate center position of the magnetic circuit. Can be reduced, and the sensitivity of the objective lens driving device 8 can be increased.

  In addition, since the focusing coils 20 and 20 and the tilt coils 22 and 22 are arranged so as to overlap each other in the focusing direction, the arrangement space can be reduced, and the optical pickup 6 can be reduced in size and thickness. it can.

  In the above, an example in which the coil body 17 is constituted by three coils of the focusing coil 20, the tracking coils 21 and 21, and the tilt coil 22 has been shown. For example, as shown in FIG. It is also possible to configure the common coil 24 that is also used for tilt adjustment and the tracking coils 21 and 21.

  In this case, two of each of the support springs 15, 15,... Function as power supply members to one common coil 24, the other common coil 24, and the tracking coils 21, 21,. To do.

  In the coil body 17A, by supplying currents in the same direction to the common coils 24, 24, the movable block 11 is moved in the focusing direction, and the strength of the supplied drive current is set to one common coil 24 and the other common coil. The movable block 11 is moved in the tilt direction by changing the position of the movable block 11.

  As described above, by using the coil bodies 17A, 17A configured by the common coils 24, 24 and the tracking coils 21, 21,..., The number of parts of the optical pickup 6 and the manufacturing cost can be reduced. Can do.

  In the above description, the lens center P of the first objective lens 18 is positioned corresponding to the first line segment Lr, and the lens center Q of the second objective lens 19 is set to the disc from the second line segment Lt. Although an example of positioning on the table 3 side is shown, conversely, the lens center Q of the second objective lens 19 is positioned corresponding to the first line segment Lr and the lens center of the first objective lens 18 is positioned. It is also possible to position P on the disk table 3 side from the second line segment Lt. In this case, preferably, the lens center P of the first objective lens 18 is directly above the lens center Q of the second objective lens 19 in a state where the disc-shaped recording medium 100 is mounted on the disc table 3. The recording track Mt is positioned immediately below.

  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.

FIG. 2 to FIG. 5 show the best mode for carrying out the present invention, and this figure is a schematic perspective view of a disk drive device. It is a schematic enlarged plan view of an objective lens driving device. It is an expansion perspective view which shows the positional relationship of each yoke part, a coil body, and each objective lens. It is a schematic plan view for demonstrating the arrangement position of an objective lens. It is an expansion perspective view which shows another coil body. FIG. 7 shows a conventional optical pickup together with FIG. 7, which is a schematic plan view showing an example in which two objective lenses are arranged apart from each other in the tangential direction. It is a schematic plan view which shows the example by which the objective lens drive device is arrange | positioned diagonally with respect to the tangential direction.

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 block, 11 ... Movable block, 15 ... Support spring, DESCRIPTION OF SYMBOLS 17 ... Coil body, 18 ... 1st objective lens, 19 ... 2nd objective lens, 20 ... Focusing coil, 21 ... Tracking coil, 22 ... Tilt coil, 17A ... Coil body, 24 ... Common coil, P ... Lens center , Q ... lens center, S ... center of rotation, Lr ... first line segment, Lt ... second line segment

Claims (8)

Each disk-shaped recording medium mounted on the disk table and having a different working wavelength includes a moving base moved in the radial direction of the disk-shaped recording medium mounted on the disk table and an objective lens driving device disposed on the moving base. Corresponding to the optical pickup that emits laser light of three types of wavelengths,
The objective lens driving device is:
A fixed block fixed to the moving base;
A disc-shaped recording medium perpendicular to the focusing direction which is a direction in which the fixed block is separated from or contacting the recording surface of the disc-shaped recording medium, a tracking direction which is a substantially radial direction of the disc-shaped recording medium, and the radial direction of the disc-shaped recording medium A movable block that is operated in a tilt direction that is a direction around an axis that extends in a tangential direction that is a tangential direction of and holds two objective lenses;
A support spring for connecting the fixed block and the movable block;
The movable block has a pair of coil bodies that are energized during operation in the focusing direction, tracking direction, or tilt direction of the movable block and are divided and arranged in the radial direction with the objective lens interposed therebetween,
One objective lens is positioned corresponding to the first line segment whose lens center extends in the radial direction through the center of rotation of the disk table,
The other objective lens has a lens center positioned away from the first line segment and positioned closer to the disc table than a second line segment extending in the tangential direction and passing through the lens center of the one objective lens. An optical pickup characterized by doing so. Make the weights of the two objectives different,
The distance from the center of the two objective lenses to the center of the tangential direction of the magnetic circuit composed of the magnet, the yoke, and the coil body on the movable block arranged on the moving base is the weight of the objective The optical pickup according to claim 1, wherein the lens is disposed close to an objective lens having a small weight. The coil body includes a focusing coil for operating the movable block in the focusing direction, a tracking coil for operating the movable block in the tracking direction, and a tilt coil for operating the movable block in the tilt direction.
The optical pickup according to claim 1, wherein the focusing coil and the tilt coil are arranged to overlap in the focusing direction. 2. The light according to claim 1, wherein the coil body includes a common coil for moving the movable block in a focusing direction and a tilt direction, and a tracking coil for moving the movable block in a tracking direction. pick up. 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. 3 corresponding to each disk-shaped recording medium having a moving base that is moved in the radial direction of the disk-shaped recording medium and an objective lens driving device arranged on the moving base and having a different use wavelength mounted on the disk table. A disk drive device configured to emit laser light of various wavelengths,
The objective lens driving device is:
A fixed block fixed to the moving base;
A disc-shaped recording medium perpendicular to the focusing direction which is a direction in which the fixed block is separated from or contacting the recording surface of the disc-shaped recording medium, a tracking direction which is a substantially radial direction of the disc-shaped recording medium, and the radial direction of the disc-shaped recording medium A movable block that is operated in a tilt direction that is a direction around an axis that extends in a tangential direction that is a tangential direction of and holds two objective lenses;
A support spring for connecting the fixed block and the movable block;
The movable block has a pair of coil bodies that are energized during operation in the focusing direction, tracking direction, or tilt direction of the movable block and are divided and arranged in the radial direction with the objective lens interposed therebetween,
One objective lens is positioned corresponding to the first line segment whose lens center extends in the radial direction through the center of rotation of the disk table,
The other objective lens is positioned closer to the disc table than the second line segment extending from the first line segment and extending through the tangential direction and passing through the lens center of the one objective lens. A disk drive device characterized by that. Make the weights of the two objectives different,
The distance from the center of the two objective lenses to the center of the tangential direction of the magnetic circuit composed of the magnet, the yoke, and the coil body on the movable block arranged on the moving base is the weight of the objective The disk drive device according to claim 5, wherein the lens is disposed closer to the objective lens having a small weight. The coil body includes a focusing coil for operating the movable block in the focusing direction, a tracking coil for operating the movable block in the tracking direction, and a tilt coil for operating the movable block in the tilt direction.
6. The disk drive device according to claim 5, wherein the focusing coil and the tilt coil are arranged so as to overlap in the focusing direction. 6. The disk according to claim 5, wherein the coil body includes a common coil for moving the movable block in the focusing direction and the tilt direction, and a tracking coil for moving the movable block in the tracking direction. Drive device.

Images