JP2008152831A - Optical pickup device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup device composed to read the signals recorded on an optical disk by using a laser beam. <P>SOLUTION: This optical pickup device is built to increase the magnetic flux density by composing tracking coils 6 attached to the lens holder 1, focusing coils 7, 8 and magnets 4, 5 for obtaining drive power together with rolling cancel coils 9, 10 of unipolar magnets. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical pickup device configured to read a signal recorded on an optical disc by laser light.

  2. Description of the Related Art Optical disk apparatuses that can perform signal reading operations and signal recording operations by irradiating a signal recording layer provided on an optical disk with laser light emitted from an optical pickup device have become widespread.

  As an optical disk apparatus, an apparatus using an optical disk called CD or DVD has been widely used, but recently, an optical disk with improved recording density, that is, a Blu-ray standard or an HD DVD (High Density Digital Versatile Disk) standard. Products that use optical disks have been commercialized.

  In order to improve the density of the signal recorded on the optical disc, it is necessary to reduce the spot diameter of the laser beam irradiated on the signal surface of the optical disc, and for this purpose, it is necessary to shorten the wavelength of the laser beam. An optical pickup device used in an optical disk device incorporates a laser diode that generates laser light.

  The laser beam used for reproducing the signal recorded on the CD standard disc described above uses infrared light, and the laser beam used for reproducing the signal recorded on the DVD standard disc. Red light is used, and blue-violet light is used as a laser beam used to reproduce signals recorded on a disc of Blu-ray standard or HD DVD standard (next generation DVD).

Then, it is conceivable that an optical disc apparatus capable of using all the optical discs of the above-mentioned standards will be commercialized. In that case, an optical pickup device capable of recording and reproducing signals from all the optical discs is required. Become. In such an optical pickup device, a method of incorporating two lenses, an objective lens for CD and DVD and an objective lens for next-generation DVD, into the optical pickup device is conceivable. (See Patent Document 1.) (See Patent Document 2.)
In an optical pickup device incorporating two objective lenses, each objective lens can be arranged side by side in a direction orthogonal to the radial direction of the optical disk. In this case, one objective lens has the same diameter as the optical disk. When the two objective lenses are arranged so as to move upward, the other objective lens moves along the diameter of the optical disc at a position away from this diameter by a certain distance. In this case, the direction of the signal track projected onto the photodetector via the objective lens that is shifted from the diameter of the optical disc shifts as the objective lens moves from the inner peripheral side to the outer peripheral side of the optical disc. . As a result, there is a problem that the optical pickup device having such a configuration cannot perform a signal recording / reproducing operation with high accuracy.

  As a method for solving such a problem, there is a method in which two objective lenses are arranged side by side in the radial direction of the optical disk. In the optical pickup device having such a configuration, when the objective lens arranged outside of the two objective lenses is moved to the innermost circumferential position of the optical disc, the objective lens arranged on the inner circumferential side is further moved from the position. It moves to the inner circumference side. When the two objective lenses are arranged side by side in the radial direction of the optical disc in this way, a clearance between the objective lens arranged on the inner peripheral side of the optical disc and the turntable on which the optical disc is placed becomes a problem. Such a problem can be solved by reducing the diameter of the two lenses or devising the shape of the lens holder.

  In an optical disc of a standard called a Blu-ray disc that is being commercialized as one of the next generation DVDs, the innermost peripheral position of the data area is shifted to the inner peripheral side as compared with other optical discs. Therefore, in order to deal with the above-described clearance problem with the turntable on which the optical disc is placed, it is advantageous to dispose the objective lens for the Blu-ray disc on the inner peripheral side of the optical disc.

  In the optical pickup device having the above-described configuration, a focus coil for performing a focusing operation and a tracking coil for performing a tracking operation are fixed to a lens holder that is mounted with an objective lens and is displaceably supported by a plurality of support wires. ing.

  In such an optical pickup device, the center of the lens holder and the lens holder are generally positioned in the tracking direction from the fact that the objective lens is attached to the upper surface of the lens holder so as to be close to the optical disk, and the arrangement of the focus coil and tracking coil and the magnetic circuit configuration. The operating point of the driving force generated when driving the displacement is shifted in the vertical direction, that is, in the optical axis direction of the objective lens, and when the lens holder is driven in the tracking direction, the lens holder rotates in the radial direction of the optical disc. Rolling, so-called rolling occurs.

In order to prevent this rolling, if the arrangement of the tracking coil and the configuration of the magnetic circuit that generates the magnetic flux to be applied to the tracking coil are devised and a drive current is passed through the tracking coil, rolling is prevented along with the driving force in the tracking direction. An objective lens driving device configured to generate a driving force in a direction is known. (See Patent Document 3)
JP-A-9-212905 JP 2001-344803 A JP 2001-222830 A

  The objective lens driving device described in Patent Document 3 requires tracking coils on both sides of one side of the lens holder facing the effective surface of the magnet, and has a magnetic pole of opposite polarity on the effective surface of the magnet in the focus direction. However, there is a problem that there are many restrictions on the magnetic circuit.

  In addition, since the boundary of the magnetic pole of the effective surface of the magnet is oblique, when the lens holder is displaced in the tracking direction and the focusing direction, the positional relationship between the magnetic pole of the effective surface of the magnet and the effective side of each tracking coil is The coil is unbalanced. That is, when the lens holder is displaced in the tracking direction, the relationship in which each tracking coil is positioned with respect to the boundary of the magnetic poles changes according to the displacement. Therefore, the driving force for preventing rolling generated by each tracking coil is unbalanced, and a moment is generated around the center of gravity of the lens holder.

  Therefore, the moment generated around the center of gravity of the lens holder changes according to the electromagnetic force generated by the drive signal supplied to each tracking coil, and rolling cannot be prevented sufficiently.

  Further, as shown in FIG. 10, a multipolar magnet is used to provide a magnetic pole having a reverse polarity on the effective surface of the magnet. However, such a multipolar magnet is a non-magnetic pole having no magnetism at the boundary of magnetization. A portion called (indicated by oblique lines) is formed. As a result, there is a problem in that the magnetic flux density obtained from the multipolar magnet provided facing the various coils fixed to the lens holder decreases.

  Therefore, if a multi-pole magnet is used as a magnet that generates a magnetic field to displace the lens holder, the magnetic flux density decreases. Therefore, in order to obtain the same driving force, it is necessary to increase the shape of the magnet. It was not suitable for downsizing the pickup device. Therefore, in order to reduce the size of the optical pickup device, there is a problem that an expensive metal must be used as the magnet material.

  The present invention is intended to provide an optical pickup device that can solve such a problem.

  The present invention includes a lens holder on which an objective lens is attached and elastically supported by a plurality of support wires so as to be displaceable with respect to the actuator frame, and is fixed to the side surface of the lens holder and fixed to the actuator frame. Driving force for displacing the lens holder in a direction perpendicular to the signal surface of the optical disc in cooperation with a first focus magnetic circuit formed by a magnetic field generated from the first and second magnets. For a second focus formed by a magnetic field generated by a first focus coil for generating a magnetic field and a third magnet and a fourth magnet fixed to the side surface of the lens holder and fixed to the actuator frame The lens holder is optically coupled with the magnetic circuit. A second focus coil that generates a driving force that is displaced in a direction perpendicular to the signal surface of the screen, and a magnetic field that is fixed to the side surface of the lens holder and that is generated from the second magnet and the fourth magnet. And a tracking coil for generating a driving force for displacing the lens holder in the tracking direction of the optical disk in cooperation with a tracking magnetic circuit formed in the above-described manner, and fixed to the side surface of the lens holder and each for the first focus A first driving force is generated in a direction that cancels rolling that occurs when the lens holder is displaced in the tracking direction by supplying a driving signal to the tracking coil in cooperation with the magnetic circuit and the second focusing magnetic circuit. And a second rolling cancellation coil The first, second, third, and fourth magnets are formed of a single pole magnet, the first and second magnets are in close contact, the third magnet and the fourth magnet are in close contact, and the second magnet and the second magnet are further in close contact with each other. 4 magnets are arranged in close contact with each other.

  Further, the present invention is characterized in that the first magnet and the third magnet are configured by a single pole magnet having the same shape, and the second magnet and the fourth magnet are configured by a single pole magnet having the same shape. To do.

  In the present invention, tracking is performed so that an axis passing through the winding center point of the tracking coil parallel to the optical axis direction of the objective lens is located on a plane connecting the center of gravity of the lens holder and the side surface of the lens holder. The coil is arranged.

  Further, the present invention is characterized in that the first focus coil and the second focus coil are arranged so as to be symmetrical with respect to the tracking coil.

  Further, the present invention is characterized in that the first rolling cancellation coil and the second rolling cancellation coil are arranged so as to be symmetrical with respect to the tracking coil.

  The present invention is characterized in that the first rolling cancellation coil and the second rolling cancellation coil are arranged so as to overlap the first focus coil and the second focus coil, respectively.

  Furthermore, the present invention is characterized in that the first and second objective lenses for performing the reading operation of signals recorded on optical disks of different standards are attached to the lens holder.

  Further, the present invention is characterized in that the first objective lens and the second objective lens are arranged so that a line connecting the central axis of the first objective lens and the central axis of the second objective lens is in the radial direction of the optical disc. It is what.

  The present invention is characterized in that the arrangement positions of various drive coils and the arrangement positions of the magnets are set so as to be axisymmetric with respect to a virtual line in the tracking direction passing through the optical axis of the objective lens. It is.

  In the present invention, the first tilt coil and the second tilt coil are wound around the lens holder around the side surface of the lens holder while shifting the positions in the optical axis direction of the objective lens. The lens holder is configured to flow drive signals in the opposite directions to the second tilt coil, and the effective side regions of the first tilt coil and the second tilt coil are made to be opposite to the magnetic pole surfaces having opposite polarities of the magnet. Is configured such that it can be tilt-driven in the radial skew direction.

  The optical pickup device of the present invention includes first and second rolling canceling coils that generate driving force in a direction that cancels rolling that occurs when the lens holder is displaced in the tracking direction by supplying a driving signal to the tracking coil. Since it is provided, not only can the rolling of the lens holder be prevented, but the magnet is composed of a single pole magnet, so the magnetic flux density can be increased, and as a result, the shape of the magnet can be reduced. The present invention has a great effect on the downsizing of the optical pickup device.

  Further, in the optical pickup device of the present invention, the first magnet and the third magnet are configured by a single pole magnet having the same shape, and the second magnet and the fourth magnet are configured by a single pole magnet having the same shape. Therefore, it is only necessary to manufacture two magnets, and an increase in cost can be suppressed.

  In the optical pickup device of the present invention, the axis passing through the winding center point of the tracking coil parallel to the optical axis direction of the objective lens is positioned on a plane connecting the center of gravity of the lens holder and the side surface of the lens holder. Since the tracking coil is arranged so that the displacement of the lens holder in the tracking direction can be suppressed.

  Further, in the optical pickup device of the present invention, the first focus coil and the second focus coil are disposed so as to be symmetrical with respect to the tracking coil, so that when the lens holder is displaced in the focus direction, Tilt can be suppressed.

  In the optical pickup device of the present invention, the first rolling cancellation coil and the second rolling cancellation coil are arranged so as to be symmetrical with respect to the tracking coil, so that the lens holder is controlled in the rolling prevention direction. It is possible to suppress the tilt when performing the operation.

In the optical pickup device of the present invention, the first rolling cancellation coil and the second rolling cancellation coil are arranged so as to overlap the first focus coil and the second focus coil, respectively, so that a common magnetic circuit can be used. This is a great effect when downsizing.

  Further, the optical pickup device of the present invention winds the first tilt coil and the second tilt coil along the side surface of the lens holder so that the first tilt coil and the second tilt coil are displaced from each other in the optical axis direction of the objective lens. The drive signal is made to flow in the opposite directions to the 1 tilt coil and the second tilt coil, and the effective side areas of the first tilt coil and the second tilt coil are made to be opposed to the magnetic pole surfaces of the magnets having opposite polarities. Since the lens holder can be tilt-driven in the radial skew direction, the optical axis of the objective lens attached to the lens holder is controlled so as to have an optimal relationship with the signal surface of the optical disc. I can do it.

  1 is a perspective view showing an embodiment of a main part of an optical pickup device according to the present invention, FIG. 2 is a perspective view showing a lens holder which is a main part of the embodiment shown in FIG. 1, and FIG. It is a perspective view which shows the magnetic circuit which is the principal part of the shown Example.

  Reference numeral 1 denotes a lens holder, in which a first objective lens 2 and a second objective lens 3 having numerical apertures corresponding to optical disks having different recording densities are arranged and fixed side by side in the tracking direction. That is, a line (shown by a virtual line A) connecting the central axis of the first objective lens 2 and the central axis of the second objective lens 3 is disposed so as to pass through the central axis of the optical disc.

  Reference numerals 4 and 5 denote a pair of magnets which are arranged so as to face each other with the lens holder 1 in between in a direction orthogonal to the tracking direction and the focus direction. That is, the magnets 4 and 5 are arranged so as to be symmetric with respect to an imaginary line A connecting the central axis of the first objective lens 2 and the central axis of the second objective lens 3.

  As shown in FIG. 4, each of the magnets 4 and 5 includes a first magnet 4A, 5A, a second magnet 4B, 5B, a third magnet 4C, 5C, and a fourth magnet 4D, 5D. Details of the configuration of the magnets 4 and 5 will be described later.

  On each side surface orthogonal to the tracking direction of the lens holder 1, a tracking coil 6 wound in a rectangular shape having a winding axis in a direction perpendicular to the tracking direction at the center and rounded corners is mounted. The first focus coil 7 and the second focus coil 8 which are wound in a rectangular shape with a winding axis in a direction perpendicular to the tracking direction and rounded corners are attached to both ends. 6. The drive coils of the first focus coil 7 and the second focus coil 8 are symmetrical with respect to a virtual line A connecting the central axis of the first objective lens 2 and the central axis of the second objective lens 3. Has been placed.

  The rectangular first rolling cancellation coil 9 with rounded corners is arranged so as to be coaxial with the first focus coil 7, and the rectangular second rolling cancellation coil 10 with rounded corners is The second focus coil 8 is arranged so as to be coaxial with the second focus coil 8. The first rolling cancellation coil 9 and the second rolling cancellation coil 10 are arranged with respect to an imaginary line A connecting the central axis of the first objective lens 2 and the central axis of the second objective lens 3 in the same manner as the focus coil. Are arranged in line symmetry.

  The drive coils of the tracking coil 6, the first focus coil 7, the second focus coil 8, the first rolling canceling coil 9, and the second rolling canceling coil 10 each have a rectangular shape with rounded corners as described above. It has a linear effective side region that effectively acts on an effective magnetic field formed by a magnetic circuit described later by being wound.

  Further, around the lens holder 1, a first tilt coil 11 and a second tilt coil 12 each having a winding axis parallel to the optical axis direction of the first objective lens 2 and the second objective lens 3 are described above. It is wound along the side surface of the lens holder 1 while shifting its position in the optical axis direction. The two sides orthogonal to the tracking direction of the first tilt coil 11 and the second tilt coil 12 are configured so as to correspond to the effective surfaces of the magnets 4 and 5 to be effective side regions.

  As shown in FIG. 3, the pair of magnets 4 and 5 respectively make magnetic field surfaces having opposite polarities relative to the effective side regions in the optical axis direction of the first objective lens 2 and the second objective lens 3 of the tracking coil 6. Thus, the magnetic field boundary is arranged at the center in the lateral direction (direction perpendicular to the optical axis direction of the objective lens). That is, as shown in FIG. 4, the right side in the figure is set to the N pole and the left side in the figure is set to the S pole, and the objectives of the first focus coil 7 and the second focus coil 8 are set. The magnetic pole boundary is formed at the center in the vertical direction (the optical axis direction of the objective lens) so as to make the magnetic pole surfaces of opposite polarities face each other in each effective side region that is orthogonal to the optical axis of the lens, Further, the lower right portion of the N pole portion on the right side in the figure is set to be a rectangular S pole, and the lower left portion of the left S pole portion in the figure is configured to be a rectangular N pole. The magnetic poles of the pair of magnets 4 and 5 are symmetrical with respect to an imaginary line A connecting the central axis of the first objective lens 2 and the central axis of the second objective lens 3 in the same manner as each drive coil. Is arranged.

  On the other hand, the winding direction of each drive coil on each side facing the magnets 4 and 5 of the lens holder 1 is set as shown in the exploded perspective view of FIG. That is, the tracking coil 6 is set so that its winding direction is opposite to each other when viewed from the same direction as indicated by solid arrows on each side surface of the lens holder 1. Since the winding directions are opposite to each other when viewed from the same direction, the winding directions are the same when viewed from the magnetic pole surfaces of the corresponding magnets. Since the magnetic poles of the pair of magnets 4 and 5 are set symmetrically with respect to the virtual line A, the longitudinal direction of the tracking coil 6 (of the objective lens) as shown in the schematic diagram from above of the magnetic circuit of FIG. Magnetic fluxes generated from the magnets 4 and 5 are effectively applied to the tracking coils 6 with respect to the tracking drive signals respectively flowing in the effective side regions in the optical axis direction). Therefore, when a tracking drive signal is supplied to each tracking coil 6, the lens holder 1 is driven in a tracking direction orthogonal to the optical axis direction of the objective lenses 2 and 3 according to the direction of the tracking drive signal. Incidentally, when the tracking drive signal in the direction indicated by the circle in FIG. 6 is supplied to each tracking coil 6, the lens holder 1 is driven in the right tracking direction in FIG.

  As shown in FIG. 5, the first focus coil 7 is set on each side surface of the lens holder 1 so that the winding directions are opposite to each other when viewed from the same direction, as indicated by solid arrows. Since it is wound in this way, the winding direction is the same when viewed from the magnetic pole face of each corresponding magnet. The magnetic poles of the pair of magnets 4 and 5 are effective sides in the lateral direction of each first focus coil 7 (direction perpendicular to the optical axis direction of the objective lens) as shown in the schematic diagram from the right side of the magnetic circuit in FIG. The magnetic flux generated by the magnets 4 and 5 is configured to act effectively on the focus drive signal that flows in each region.

  Further, as shown in FIG. 6, the second focus coil 8 is set on each side surface of the lens holder 1 so that the winding directions are opposite to each other as seen from the same direction as indicated by solid arrows. Since it is wound in this way, the winding direction is the same when viewed from the magnetic pole face of each corresponding magnet. The magnetic poles of the pair of magnets 4 and 5 are effective sides in the lateral direction of each second focus coil 8 (direction perpendicular to the optical axis direction of the objective lens) as shown in the schematic diagram from the left side of the magnetic circuit in FIG. The magnetic flux generated by the magnets 4 and 5 is configured to act effectively on the focus drive signal that flows in each region.

  Moreover, the second focus coil 8 is configured such that the winding direction is opposite to that of the first focus coil 7 disposed on the same side surface of the lens holder 1 as shown in FIG. The first focus coil 7 and the second focus coil 8 are supplied with the first focus coil 7 and the second focus coil 8 at the same time because the magnetic poles of the magnets 4 and 5 facing each other are reversed in polarity. The driving force in the same direction is generated with respect to the focus driving signal.

  Incidentally, when the focus drive signal in the direction indicated by the solid circle in FIGS. 7 and 8 is supplied to each first focus coil 7 and each second focus coil 8, the lens holder 1 in FIGS. It will be driven upward.

  Further, as shown in FIG. 5, the first rolling cancellation coil 9 is configured such that the winding directions are opposite to each other when viewed from the same direction, as indicated by the solid line arrow, on each side surface of the lens holder 1. ing. Thus, since the winding directions are opposite to each other when viewed from the same direction, the winding directions are the same when viewed from the magnetic pole surfaces of the corresponding magnets. As shown in FIG. 7, the magnetic poles of the pair of magnets 4 and 5 are generated from the magnets 4 and 5 with respect to the drive signals that flow in the lateral effective side regions of the first rolling cancellation coils 9, respectively. The magnetic flux is configured to act effectively.

  Further, as shown in FIG. 5, the second rolling cancellation coil 10 is configured such that the winding directions are opposite to each other when viewed from the same direction, as indicated by the solid line arrows, on each side surface of the lens holder 1. ing. Thus, since the winding directions are opposite to each other when viewed from the same direction, the winding directions are the same when viewed from the magnetic pole surfaces of the corresponding magnets. As shown in FIG. 8, the magnetic poles of the pair of magnets 4 and 5 are generated from the magnets 4 and 5 with respect to the drive signals respectively flowing in the lateral effective side regions of the second rolling cancellation coils 10. The magnetic flux is configured to act effectively.

  The second rolling cancellation coil 10 is set to have the same winding direction as the first rolling cancellation coil 9 disposed on the side surface of the lens holder 1 as shown in FIG. In the first rolling cancellation coil 9 and the second rolling cancellation coil 10, the magnetic poles of the opposed magnets 4 and 5 are opposite in polarity, so the first rolling cancellation coil 9 and the second rolling cancellation coil 10 means that a driving force in the opposite direction is generated with respect to the driving signals supplied at the same time. Therefore, the lens holder 1 is driven in the opposite direction on the side where the first rolling cancellation coil 9 is disposed and the side where the second rolling cancellation coil 10 is disposed, so that the lens holder 1 is moved to the optical disk. A displacement force that tilts in the radial direction is generated.

  Incidentally, when a tracking drive signal is supplied to each of the first rolling cancellation coil 9 and the second rolling cancellation coil 10 in the direction indicated by the broken circle in FIGS. 7 and 8, the lens holder 1 is shown in FIG. As shown in FIG. 8, an upward driving force is generated on the half side of the lens holder 1 where the first rolling canceling coils 9 are arranged, and each second rolling canceling coil 10 of the lens holder 1 is shown in FIG. A downward driving force is generated on the half side where the is disposed.

Next, the first tilt coil 11 and the second tilt coil 12 are wound around the side surface of the lens holder 1, but the winding directions are opposite to each other. The effective side regions of the first tilt coil 11 are reversed left and right with respect to the position opposite to the central magnetic pole boundary in the lateral direction of the magnets 4 and 5 (direction perpendicular to the optical axis direction of the objective lens). Each effective side region of the second tilt coil 12 is opposed to the magnetic pole of polarity, and the position is opposed to the central magnetic pole boundary in the lateral direction of the magnets 4 and 5 (direction perpendicular to the optical axis direction of the objective lens). Thus, the magnetic poles of the magnets 4 and 5 that are opposite to the left and right magnetic poles having opposite polarities, and that are opposed to the effective side regions of the first tilt coil 11 except for the center, are opposite to the magnetic poles having opposite polarities.

  Therefore, when a tilt drive signal is supplied to the first tilt coil 11 and the second tilt coil 12, driving in the focus direction is performed in the opposite direction on the left and right of each effective side area of the first tilt coil 11 and the second tilt coil 12. Since a force is generated, a driving force for tilting the lens holder 1 in the radial direction of the optical disk is generated. In this case, a driving force that cancels the driving force tilted at the central portion of each effective side region of the second tilt coil 12 is generated, but the driving force is sufficient as compared with the driving force that tilts the lens holder 1 in the radial direction. The effect is negligible.

  As described above, each drive coil is fixed to the lens holder 1, and attachment of each coil to the lens holder 1 will be described. When each coil is fixed to the lens holder 1, first, the first tilt coil 11 and the second tilt coil 12 are continuously wound along the side surface of the lens holder 1, and the first tilt coil 11 and the second tilt coil are wound. The coil 12 is connected.

  Next, each first focus coil 7 and each second focus coil 8 are continuously wound around each side surface of the lens holder 1. The first focus coil 7 and the second focus coil 8 disposed on each side surface of the lens holder 1 are connected to each other, and the strands of the drive coil are connected to the first focus coil 7 and the first focus coil 7 on one side of the lens holder 1. The second focus coil 8 is continuously and sequentially wound along the first tilt coil 11, and then the element wire is guided along the first tilt coil 11 to the other surface side of the lens holder 1. The second focus coil 8 and the first focus coil 7 on the other surface side are continuously and sequentially wound along the first tilt coil 11.

  Next, each tracking coil 6, each first rolling cancellation coil 9, and second rolling cancellation coil 10 are continuously wound around each side surface of the lens holder 1. Each tracking coil 6, each first rolling cancellation coil 9, and each rolling cancellation coil 10 disposed on each side surface of the lens holder 1 are connected to each other, and a tracking drive signal supplied to each tracking coil 6 is connected to each tracking coil 6. The first rolling cancellation coil 9 and the second rolling cancellation coil 10 are also supplied.

  In order to connect these drive coils to each other, the second rolling canceling coil 10, the tracking coil 6 and the first rolling canceling coil 9 on the one surface side of the lens holder 1 are used as the second tilt coil. The first rolling cancellation coil 9, the tracking coil 6, and the second rolling cancellation coil 10 on the other side of the lens holder 1 are guided along the second tilt coil 12. Wind continuously one after another.

  The drive coils of each tracking coil 6, each first focus coil 7, each second focus coil 8, each first rolling cancellation coil 9 and each second rolling cancellation coil 10 are provided on each side of the lens holder 1. It is formed by winding a wire around the formed bobbin portion, and on each side surface of the lens holder 1, the bobbin portion 13 around which the tracking coil 6 is wound, the first focus coil 7 and the first rolling cancellation. A bobbin portion 14 around which the coil 9 is coaxially wound, and a bobbin portion 15 around which the second focus coil 8 and the second rolling cancellation coil 10 are coaxially wound are integrally provided.

As described above, various drive coils are attached to the lens holder 1. The lens holder 1 has one end fixed to the lens holder 1 and the other end on a predetermined side wall of the actuator frame 20 as an auxiliary member 23. The focusing direction, the tracking direction, and the tracking direction with respect to the actuator frame 20 by the six support wires 22 on both sides of each of the three sides fixed to the fixed substrate 21 fixed integrally with the auxiliary member 23 via It is elastically supported so that it can be displaced in the radial direction.

  In this case, each support wire 22 is installed in a C shape so that the distance on the lens holder 1 side in the tracking direction is slightly narrower than the distance on the fixed substrate 21 side, and the rolling natural frequency of the movable part including the lens holder 1 is set. Is configured to be high. In addition, each support wire 22 passes through each hole formed in the auxiliary member 23 three by one side, and is surrounded by a dumping agent 24 filled in each hole for vibration suppression.

  As described above, one end of the six support wires 22 that elastically support the lens holder 1 with respect to the actuator frame 20 so as to be displaceable is fixed to the fixed substrate 21, but the other end is the lens holder. 1 is arranged in contact with or close to a predetermined protrusion 25 integrally formed on each side surface. The strands of the drive coils wound continuously around the lens holder 1, that is, the strands of the first tilt coil 11 and the second tilt coil 12, the first focus coils 7, and the second focus coils 8. Since both ends of the strands, the strands of each tracking coil 6, the strands of each first rolling cancellation coil 9 and each second rolling cancellation coil 10 are respectively entangled with a predetermined protrusion 25, this A predetermined support wire 22 and a predetermined drive coil are associated with each other and electrically connected by soldering to the ends of the strands of each drive coil entangled with the predetermined protrusion 25.

  According to such a configuration, the supply of the drive signal to each drive coil is performed via the predetermined support wire 22. For example, the supply of the tilt drive signal to the first tilt coil 11 and the second tilt coil 12 is performed via the support wire 22 installed in the middle in the vertical direction on both the left and right side surfaces, and each first focus coil 7. The supply of the focus drive signal to each of the second focus coils 8 is performed via the support wires 22 installed on the top and bottom of one side surface. Further, the supply of the tracking drive signal to each tracking coil 6, each first rolling canceling coil 9, and each second rolling canceling coil 10 is supported at the top and bottom on the other side. This is done via the wire 22.

  When a tilt drive signal is supplied to the first tilt coil 11 and the second tilt coil 12, the focus directions are opposite to each other with the center of the effective side area of the first tilt coil 11 and the second tilt coil 12 as a boundary. The driving force is generated. Therefore, the lens holder 1 is driven in the radial skew direction in a direction corresponding to the polarity of the tilt drive signal and a displacement amount corresponding to the current amount of the tilt drive signal.

  Further, when a focus drive signal is supplied to each first focus coil 7 and each second focus coil 8, a driving force is generated in each first focus coil 7 and each second focus coil 8 in the same focus direction. The Therefore, the lens holder 1 is driven in the focus direction by a displacement amount corresponding to the current amount of the focus drive signal in a direction corresponding to the polarity of the focus drive signal.

  Further, when a tracking drive signal is supplied to each tracking coil 6, a driving force is generated in each tracking coil 6 in the same tracking direction. Therefore, the lens holder 1 is driven in the tracking direction by a displacement amount corresponding to the current amount of the tracking drive signal in a direction corresponding to the polarity of the tracking drive signal.

  In this embodiment, as shown in FIG. 9, the first objective lens 2 and the second objective lens 3 are arranged on the upper surface of the lens holder 1 so as to approach the optical disk, and the structure of the lens holder 1 or each drive coil. The center of gravity G of the actuator movable portion including the lens holder 1 is biased upward from the center of the lens holder 1 due to the arrangement of the above and the configuration of the magnetic circuit. On the other hand, the operating point A of the driving force generated when the lens holder 1 is driven in the tracking direction is substantially the center in the optical axis direction of the objective lenses 2 and 3 of the lens holder 1, and the center of gravity G of the actuator movable portion and Is shifted in the optical axis direction. Therefore, when the lens holder 1 is driven in the tracking direction, a rolling force that tilts the lens holder 1 in the radial direction of the optical disk is generated.

  When a tracking drive signal is supplied to each tracking coil 6, the tracking drive signal is also supplied to each first rolling cancellation coil 9 and each second rolling cancellation coil 10 connected to each tracking coil 6. The When a tracking drive signal is supplied to each first rolling cancellation coil 9 and each second rolling cancellation coil 10, the side of the lens holder 1 where the first rolling cancellation coil 9 is disposed and the second rolling cancellation coil. Driving force in the focusing direction is generated in the opposite direction on the side where the coil 10 is disposed. Therefore, the lens holder 1 is driven in the radial skew direction in a direction corresponding to the polarity of the tracking drive signal and a displacement amount corresponding to the current amount of the tracking drive signal.

  A driving force in the radial skew direction generated in the lens holder 1 when a tracking drive signal is supplied to each of the first rolling cancellation coils 9 and each of the second rolling cancellation coils 10, the tracking drive signal is applied to each tracking coil 6. Corresponds to the amount of rolling generated according to the driving force in the tracking direction generated in the lens holder 1 when the tracking drive signal is supplied to the tracking coil 6 in the radial skew direction. The direction of the rolling force generated according to the driving force in the tracking direction generated in the lens holder 1 is set in the opposite direction.

  Therefore, when a tracking drive signal is supplied to each tracking coil 6 and a force Fr for rolling the lens holder 1 is generated as shown in FIG. 9, each first rolling cancellation coil 9 and each second rolling cancellation coil 10 are simultaneously generated. The tracking drive signal is supplied to the first rolling cancellation coil 9 and the second rolling cancellation coil 10 and the driving force Fc generated by the tracking drive signal supplied to the second rolling cancellation coil 10 is generated.

  The direction of the force Fr that rolls the lens holder 1 during the tracking operation is opposite to the direction of the driving force Fc generated by the tracking drive signal supplied to each first rolling cancellation coil 9 and each second rolling cancellation coil 10. Therefore, rolling during the tracking operation of the lens holder 1 can be suppressed.

  As described above, the optical pickup device according to the present invention is configured. Next, the configuration of the magnets 4 and 5 will be described with reference to FIG. As described with reference to FIG. 4, the magnets 4 and 5 are respectively composed of the first magnets 4A and 5A, the second magnets 4B and 5B, the third magnets 4C and 5C, and the fourth magnets 4D and 5D. Yes.

  As shown in FIG. 11, the first magnet 4A, the second magnet 4B, the third magnet 4C, and the fourth magnet 4D are configured by single pole magnets having N poles and S poles that are individually separated. Further, as is apparent from the drawings, the first magnet 4A and the third magnet 4C are the same magnet, and the second magnet 4B and the fourth magnet 4D are the same magnet. The magnet 5 is a magnet having the same configuration although it is arranged so as to have a polarity opposite to that of the magnet 4.

  In the magnet having such a configuration, the first magnets 4A and 5A and the second magnets 4B and 5B are brought into close contact with each other, the third magnets 4C and 5C and the fourth magnets 4D and 5D are brought into close contact with each other, and further the second magnets 4B and 5B. And the fourth magnets 4D and 5D are brought into close contact with each other, whereby the magnets 4 and 5 shown in FIG. 4 are formed.

  FIG. 12 shows the relationship between the magnet 4, the tracking coil 6, the first focus coil 7, and the second focus coil 8, and is formed by a magnetic field generated from the first magnet 4A and the second magnet 4B. The first focus coil 7 is disposed in the first focus magnetic circuit, and the second focus is formed in the second focus magnetic circuit formed by the magnetic field generated from the third magnet 4C and the fourth magnet 4D. The coil 8 is disposed, and the tracking coil 6 is disposed in a tracking magnetic circuit formed by a magnetic field generated from the second magnet 4B and the fourth magnet 4D.

  In such a configuration, when a tracking drive signal in the arrow direction flows through the tracking coil 6, a driving force in the arrow X direction is generated in the tracking coil 6. That is, the X direction is the tracking direction of the optical disc, and becomes a driving force that displaces the lens holder 1 in the tracking direction. Therefore, an operation for controlling the position of the lens holder 1, that is, the objective lens 2 and 3 in the tracking direction, by changing the direction of the tracking drive signal flowing through the tracking coil 6 and the magnitude of the drive signal, so-called tracking control operation is performed. I can do it.

  Further, when a focus drive signal in the arrow direction flows through the first focus coil 7 and the second focus coil 8, a drive force in the arrow Y direction is generated in the first focus coil 7 and the second focus coil 8. . That is, the Y direction is the signal surface direction of the optical disk, and becomes a driving force that displaces the lens holder 1 in the signal surface direction of the optical disk. Therefore, the position of the lens holder 1, that is, the focus direction of the objective lenses 2 and 3 is controlled by changing the direction of the focus drive signal flowing through the first focus coil 7 and the second focus coil 8 and the magnitude of the drive signal. Operation, so-called focus control operation can be performed.

  As described above, the drive displacement operation of the lens holder 1 for the tracking control operation and the focus control operation is performed, but the first rolling cancellation coil 9, the second rolling cancellation coil 10, the first tilt coil 11, and the like. Since the driving displacement operation of the lens holder 1 by the second tilt coil 12 can be performed on the same principle, the description thereof is omitted.

It is a perspective view which shows one Example of the principal part of the optical pick-up apparatus which concerns on this invention. It is a perspective view which shows the lens holder which is the principal part of the Example shown in FIG. It is a perspective view which shows the magnetic circuit which is the principal part of the Example shown in FIG. It is a perspective view which shows the magnet which comprises the optical pick-up apparatus which concerns on this invention. It is a disassembled perspective view for demonstrating the winding direction of each drive coil which comprises the optical pick-up apparatus which concerns on this invention. It is the schematic diagram seen from the top for demonstrating the magnetic circuit which comprises the optical pick-up apparatus based on this invention. It is the schematic diagram seen from the right for demonstrating the magnetic circuit which comprises the optical pick-up apparatus which concerns on this invention. It is the schematic diagram seen from the left for demonstrating the magnetic circuit which comprises the optical pick-up apparatus which concerns on this invention. It is a figure for demonstrating the operation | movement which prevents generation | occurrence | production of the rolling of the lens holder which comprises the optical pick-up apparatus which concerns on this invention. It is a figure for demonstrating a multipolar magnet. It is a figure for demonstrating the structure of the magnet which comprises the optical pick-up apparatus which concerns on this invention. It is a figure for demonstrating the relationship between the magnet and drive coil which comprise the optical pick-up apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens holder 2 1st objective lens 3 2nd objective lens 4, 5 Magnet 6 Tracking coil 7 1st focus coil 8 2nd focus coil 9 1st rolling cancellation coil 10 2nd rolling cancellation coil 11 1st tilt coil 12 Second tilt coil 20 Actuator frame 21 Fixed substrate 22 Support wire 23 Auxiliary member

Claims (10)

A lens holder to which an objective lens is attached and elastically supported by a plurality of support wires so as to be displaceable with respect to the actuator frame, and a first lens holder fixed to the side of the lens holder and fixed to the actuator frame A first driving force is generated for displacing the lens holder in a direction perpendicular to the signal surface of the optical disk in cooperation with a first focus magnetic circuit formed by a magnetic field generated from the first magnet and the second magnet. A focus coil and a second focus magnetic circuit formed by a magnetic field generated from a third magnet and a fourth magnet fixed to the side surface of the lens holder and fixed to the actuator frame; The lens holder is attached to the optical disc by cooperation. A second focus coil that generates a driving force that is displaced in a direction perpendicular to the surface; and a magnetic field that is fixed to a side surface of the lens holder and that is generated from the second magnet and the fourth magnet. A tracking coil for generating a driving force for displacing the lens holder in the tracking direction of the optical disk in cooperation with the tracking magnetic circuit, and a first focusing magnetic circuit fixed to a side surface of the lens holder, First and second driving forces are generated in a direction to cancel rolling that occurs when the lens holder is displaced in the tracking direction by supplying a driving signal to the tracking coil in cooperation with the second focus magnetic circuit. It consists of a rolling cancellation coil, The third and fourth magnets are composed of single pole magnets, the first and second magnets are in close contact, the third magnet and the fourth magnet are in close contact, and the second and fourth magnets are in close contact with each other. An optical pickup device characterized by being arranged. The first magnet and the third magnet are configured by a single pole magnet having the same shape, and the second magnet and the fourth magnet are configured by a single pole magnet having the same shape. Optical pickup device. The tracking coil is disposed so that the axis passing through the winding center point of the tracking coil parallel to the optical axis direction of the objective lens is located on a plane connecting the center of gravity of the lens holder and the side surface of the lens holder. The optical pickup device according to claim 1. 4. The optical pickup device according to claim 3, wherein the first focus coil and the second focus coil are arranged so as to be symmetrical with respect to the tracking coil. 4. The optical pickup device according to claim 3, wherein the first rolling cancellation coil and the second rolling cancellation coil are arranged so as to be symmetrical with respect to the tracking coil. 5. The optical pickup device according to claim 4, wherein the first rolling cancellation coil and the second rolling cancellation coil are arranged so as to overlap the first focus coil and the second focus coil, respectively. 2. The optical pickup device according to claim 1, wherein the first and second objective lenses for performing a reading operation of signals recorded on optical disks of different standards are attached to the lens holder. 8. The first objective lens and the second objective lens are arranged so that a line connecting the central axis of the first objective lens and the central axis of the second objective lens is in a radial direction of the optical disc. The optical pickup device described. 9. The arrangement position of various drive coils and the arrangement position of each magnet are set so as to be symmetrical with respect to a virtual line in the tracking direction passing through the optical axis of the objective lens. An optical pickup device according to claim 1. The first tilt coil and the second tilt coil are wound around the lens holder along the side surface of the lens holder while shifting the positions in the optical axis direction of the objective lens, respectively, to the first tilt coil and the second tilt coil. The lens holder is tilted in the radial skew direction so that the drive signals flow in opposite directions and the effective side regions of the first and second tilt coils are opposed to the magnetic pole surfaces of opposite polarities of the magnet. The optical pickup device according to claim 9, wherein the optical pickup device is configured to be driven.

Images