JP2006344263A - Optical disk drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk drive which can record or reproduce an optical disk recorded in a density higher than before and control the tilt of an objective lens more correctly than before. <P>SOLUTION: This drive has a movable frame 22 carrying an optical pickup 21; support frames 23a, 23b for the movable frame 22; elastic supports 24a, 24b to move the movable frame 22 against the support frames 23a, 23b; magnets 27a, 27b arranged on the movable frame; and a 1st and 2nd electromagnets 28a, 28b, 29a, 29b, 2a, 32b, 33a, and 33b arranged on the support frames 23a, 23b. The movable frame 22 is moved by supplying drive currents to the 1st and 2nd electromagnets 28a, 28b, 29a, 29b, 2a, 32b, 33a, and 33b to produce attraction or repulsion forces between the magnets 27a, 27b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical disc apparatus that supports an optical pickup unit with an elastic body.

  Among optical discs, there are a first optical disc having a standard recording density such as a compact disc (CD: Compact Disc), and a second disc such as a digital versatile disc (DVD) that is recorded on the first optical disc at a high density. In addition, there is a third optical disc such as a Blu-ray Disc (BD) that is recorded at a higher density than the second optical disc.

  By the way, in the field of optical discs, most of them have a diameter of 12 cm or smaller. In the field of optical discs, it is required to record more information signals, but from the viewpoint of ease of use, it is not desirable to increase the diameter. For this reason, further improvement in recording density per unit area is required. Therefore, as a technique that enables higher-density recording than the third optical disk, there is an optical disk apparatus that uses a solid immersion lens (SIL) as an objective lens of an optical pickup, as disclosed in Patent Document 1.

  In such an optical disc apparatus using a solid immersion lens, the distance between the optical disc and the objective lens is very close, and therefore the tilt error margin is more strict than that of the third optical disc.

  Further, in the optical disk apparatus, the objective lens needs to maintain a state that is perpendicular and parallel to the disk surface of the optical disk during recording and reproduction. However, the objective lens may be unable to maintain a state perpendicular to and parallel to the disk surface due to tilting of the objective lens and the optical disk due to vibration or the like. Further, the objective lens may not be able to maintain a state that is perpendicular and parallel to the disk surface due to manufacturing errors of the optical disk.

  In an optical disk apparatus capable of recording at a higher density than the third optical disk, the objective lens and the optical disk are very close to each other, and the tilt error margin is strict, so the attitude control of the objective lens is extremely important.

Japanese Patent Laid-Open No. 5-189796

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical disc apparatus that enables recording and reproduction of an optical disc that is recorded at a higher density than in the past.

  Another object of the present invention is to provide an optical disc apparatus capable of more accurately controlling the attitude of the objective lens.

  A further object of the present invention is to provide an optical disc apparatus capable of controlling the attitude of an objective lens in real time.

  An optical disc apparatus according to the present invention includes a movable frame on which an optical pickup unit is disposed, a support frame that supports the movable frame, and an elastic body that elastically supports the movable frame so that the movable frame can move relative to the support frame. And a driving means for moving the movable frame relative to the support frame, the magnet having a magnet disposed on either the movable frame or the support frame and an electromagnet disposed on the other. .

  According to the present invention, the electromagnet changes to the same or different polarity as the opposing magnet, thereby generating an attractive force and a repulsive force against the magnet, and displacing the elastic body by the attractive force and the repulsive force, so that the optical pickup unit Can be moved. Thereby, tilt control can be performed in addition to focusing control and tracking control of the objective lens.

  Hereinafter, an optical disk device to which the present invention is applied will be described with reference to the drawings.

  As shown in FIG. 1, an optical disk apparatus 1 to which the present invention is applied is rotated by a disk rotation driving apparatus 10 that rotates an optical disk 2 on which an information signal is recorded and a disk rotation driving apparatus 10 as shown in FIG. And an optical pickup device 20 that irradiates the optical disc 2 with a light beam and detects a return light beam reflected by the optical disc 2. The disk rotation driving device 10 and the optical pickup device 20 are disposed on the base 4.

  As shown in FIG. 1, the disk rotation driving device 10 that rotates the optical disk 2 includes a disk table 12 on which the optical disk 2 is mounted on a spindle of a spindle motor 11 that is a driving source. The disc table 12 is formed with a centering portion 13 that is engaged with the center hole 3 of the optical disc 2 at the center, and a disc support portion 14 that supports the periphery of the center hole 3 of the optical disc 2 is formed around the centering portion 13. Has been. The optical disc 2 has a center hole 3 engaged with a centering portion 13, the periphery of the center hole 3 is supported by a disc support portion 14, and is further sandwiched between the disc table by a clamping plate or the like. And rotate together. The optical disk 2 is rotated by the disk drive device 10 by a method such as CLV (Constant Linear Velocity), CAV (Constant Angular Velocity), ZCLV (Zone Constant Linear Velocity), ZCAV (Zone Constant Angular Velocity), or the like.

  Further, as shown in FIGS. 1 and 2, the optical pickup device 20 includes an optical pickup unit 21 provided with a light source and an optical block, a movable frame 22 to which the optical pickup unit 21 is attached, and the movable frame 22 is elastic. And a support frame 23 attached via a body 24.

  The optical pickup unit 21 has an optical block that collects a light beam emitted from a semiconductor laser serving as a light source by an objective lens 21a and detects a returned light beam reflected by the optical disc 2 by a photodetector. Here, for example, in order to realize high-density recording on the optical disc 2, the light beam has a wavelength of about 400 nm, and the objective lens 21a is a solid immersion lens. As described above, since the optical pickup unit 21 uses a solid immersion lens as the objective lens 21a and uses a light beam with a short wavelength, the working distance that is the distance between the objective lens 21a and the disc surface of the optical disc 2 is about 20 nm. And will be very close. Therefore, in the optical pickup device 20, in addition to the attitude control of the objective lens 21a, in order to prevent the optical disc 2 and the objective lens 21a from colliding, in addition to the biaxial actuator 21b of the objective lens 21a, a second type as will be described later. The first and second driving units 26 and 30 are provided.

  The optical pickup unit 21 includes a biaxial actuator 21b that displaces the objective lens 21a in the focusing direction that is the optical axis direction and that is driven and displaced in a direction orthogonal to the track of the optical disc 2, for example, as a focusing drive unit. And a fixed part magnet, and a tracking coil and a magnet as a tracking drive part. The objective lens 21a is held by a lens holder serving as a movable portion, and is supported so as to be displaceable by an elastic linear member with respect to the fixed portion. The focusing and tracking coils are attached to the movable part, and the magnet is attached to the fixed part. The biaxial actuator 21b supplies a driving current to the focusing coil so that the focusing error signal becomes zero, and an objective lens attached to a lens holder that is a movable part with respect to a fixed part to which a magnet or the like is attached. 21a is displaced in the direction of the optical axis, and a drive current is supplied to the tracking coil so that the tracking error signal becomes zero, and the objective lens 21a is displaced in a direction perpendicular to the recording track of the optical disc 2.

  As shown in FIG. 2, the optical pickup unit 21 configured as described above is disposed on the pickup base 25, and the pickup base 25 on which the optical pickup unit 21 is disposed is attached to the movable frame 22. It is attached. The movable frame 22 is supported by the elastic bodies 24a and 24b and attached to the support frames 23a and 23b. As shown in FIGS. 1 and 2, the movable frame 22 has a substantially rectangular shape, and a pickup base 25 to which the optical pickup unit 21 is positioned and attached is attached to one main surface thereof. Elastic bodies 24a and 24b are attached to the movable frame 22 along the longitudinal direction. Specifically, the elastic bodies 24 a and 24 b are provided in the extending direction of each long side of the movable frame 22. The elastic bodies 24 a and 24 b attached to the long sides of the movable frame 22 are elastic linear members such as wires, and elastically support the movable frame 22 with respect to the support frame 23. The elastic body 24 may be a coil spring, a leaf spring, rubber or the like in addition to the wire.

  The support frame 23 is a pair, one support frame 23 a supports one side of the movable frame 22 in the longitudinal direction, and the other support frame 23 b supports the other side of the movable frame 22 in the longitudinal direction. . Each support frame 23 a, 23 b is formed with a locking piece 25 a at which the end of the elastic body 24 is locked at both corners on the outer side with respect to the movable frame 22. The movable frame 22 is elastically supported on the support frame 23 by the elastic bodies 24a and 24b.

  The movable frame 22 and the support frames 23a and 23b are provided with a first drive unit 26 that displaces the movable frame 22 elastically supported by the elastic bodies 24a and 24b with respect to the support frames 23a and 23b. As shown in FIGS. 3 and 4, the drive unit 26 for displacing the movable frame 22 has magnets 27 a and 27 b that are magnetic field generating members and first magnets 27 a and 27 b that are opposed to the magnets 27 a and 27 b on both sides in the longitudinal direction. Electromagnets 28a, 28b, 29a, 29b.

  The magnets 27a and 27b are long members and are arranged on the back surface in parallel with the short side of the movable frame 22. One end is magnetized to the N pole and the other end is magnetized to the S pole. The first electromagnets 28 a, 28 b, 29 a, and 29 b are formed by winding a coil around a bobbin, and are attached to support frames 23 a and 23 b that face the back surface of the movable frame 22. The first electromagnets 28a and 28b are attached to the inner side of the support frame 23a on the movable frame 22 side, and the first electromagnets 29a and 29b are attached to the inner side of the support frame 23b on the movable frame 22 side. The ends of the first electromagnets 28a, 28b, 29a, 29b facing the magnets 27a, 27b are switched to the N pole and the S pole depending on the direction of the drive current flowing in the coil, and the same polarity as the facing magnets 27a, 27b. Then, a repulsive force that separates the movable frame 22 from the support frames 23a and 23b is generated, and when it has a different polarity from the opposing magnets 27a and 27b, an attractive force that attracts the movable frame to the support frames 23a and 23b is generated. generate. That is, the first electromagnets 28 a, 28 b, 29 a and 29 b generate a driving force that displaces the movable frame 22 in a direction perpendicular to the disk surface of the optical disk 2 mounted on the disk table 12.

  Further, as shown in FIGS. 3 and 5, the second drive unit 30 is attached to the support pieces 31 a and 31 b erected on the inner side of the support frames 23 a and 23 b on the movable frame 22 side. It has electromagnets 32a, 32b, 33a, 33b. The second electromagnets 32a, 32b, 33a, 33b are also formed by winding a coil around a bobbin. The second electromagnets 32a and 32b attached to the support piece 31a provided on the support frame 23a face the end surface of the magnet 27a of the movable frame 22 and are attached to the support piece 31b provided on the support frame 23b. The two electromagnets 33 a and 33 b face the end surface of the magnet 27 b of the movable frame 22. The ends of the second electromagnets 32a, 32b, 33a, 33b facing the magnets 27a, 27b are switched to the N pole and the S pole depending on the direction of the drive current flowing in the coil, and the same polarity as the opposing magnets 27a, 27b. At this time, a repulsive force is generated for the magnets 27a and 27b, and an attracting force for the magnets 27a and 27b is generated when the repulsive force is different from that of the opposing magnets 27a and 27b. That is, the second electromagnets 32 a, 32 b, 33 a, 33 b generate a driving force that displaces the movable frame 22 in a direction parallel to the disk surface of the optical disk 2 mounted on the disk table 12.

  By the way, as shown in FIG. 1, the support frames 23a and 23b in which the movable frame 22 is supported by the elastic bodies 24a and 24b are used to feed the optical pickup unit 21 in the radial direction of the optical disc 2 mounted on the disc table 12. A mechanism 36 is provided. The feed mechanism 36 is a mechanism using a linear motor, a feed screw, or the like, and feeds the optical pickup unit 21 supported by the support frames 23a and 23b in the radial direction of the optical disc 2. Here, as shown in FIG. 1, the feed mechanism 36 supports the movable frame 22 and the support frames 23 a and 23 b so that the longitudinal direction thereof is orthogonal to the radial direction of the optical disc 2. That is, the feed mechanism 36 supports the movable frame 22 and the support frames 23 a and 23 b so that the short sides thereof are in the radial direction of the optical disc 2, so that the objective lens 21 a of the optical pickup unit 21 is in the innermost peripheral region of the optical disc 2. To be able to access up to.

  The optical disk apparatus 1 configured as described above drives the disk rotation driving device 10 to record the information signal on the optical disk 2 or to reproduce the information signal recorded on the optical disk 2, and to the disk table 12. The mounted optical disk 2 is rotated at a predetermined speed. At the same time, the optical pickup device 20 drives the semiconductor laser to detect the returning light beam reflected by irradiating the disk surface of the rotating optical disk 2, thereby focusing and tracking the objective lens 21a. Information signals are recorded and reproduced while performing control and further skew control. Such control of the objective lens 21a is performed by the above-described first and second driving units 26 and 30 in addition to the biaxial actuator 21b.

  Next, operations of the first and second drive units 26 and 30 provided in the optical pickup device 20 when performing an information signal recording / reproducing operation will be described.

  FIG. 6 shows a state in which the movable frame 22 is tilted in the radial direction of the optical disc 2 mounted on the disc table 12 using the first electromagnets 28a, 28b, 29a, 29b shown in FIG. In this case, a driving current in one direction is supplied to the first electromagnets 28a and 29a located on one long side of the support frames 23a and 23b, and a driving current in the other direction is supplied to the first electromagnets 28b and 29b. . As a result, the first electromagnets 28a and 29a have different polarities from the opposing magnets 27a and 27b and generate an attractive force A, and the first electromagnets 28b and 29b have the same polarity as the opposing magnets 27a and 27b. The repulsive force R is generated. In the movable frame 22 to which the optical pickup unit 21 is attached, the elastic bodies 24 a and 24 b are deformed by the attractive force A and the repulsive force R, and are inclined to one side in the radial direction of the optical disc 2. When the movable frame 22 is tilted in the direction opposite to that shown in FIG. 6, a driving current opposite to that in the above example may be supplied to the first electromagnets 28a, 28b, 29a, 29b. Thus, the optical pickup device 20 can perform tilt control in the radial direction of the optical disc 2 of the objective lens 21a.

  FIG. 7 shows a state in which the movable frame 22 is tilted in the tangential direction of the optical disc 2 mounted on the disc table 12 using the first electromagnets 28a, 28b, 29a, 29b shown in FIG. In this case, a drive current in one direction is supplied to the first electromagnets 28a and 28b located on one short side of the support frames 23a and 23b, and a drive current in the other direction is supplied to the first electromagnets 29a and 29b. . As a result, the first electromagnets 28a and 28b have different polarities from the opposing magnets 27a and 27b and generate an attractive force A, and the first electromagnets 29a and 29b have the same polarity as the opposing magnets 27a and 27b. The repulsive force R is generated. In the movable frame 22 to which the optical pickup unit 21 is attached, the elastic bodies 24 a and 24 b are deformed by the attractive force A and the repulsive force R, and are inclined to one side in the tangential direction of the optical disc 2. When the movable frame 22 is tilted in the direction opposite to that shown in FIG. 7, a driving current opposite to that in the above example may be supplied to the first electromagnets 28a, 28b, 29a, 29b. Thereby, the optical pickup device 20 can perform tilt control of the objective lens 21a in the tangential direction of the optical disc 2.

  FIG. 8 shows a state in which the movable frame 22 is rotated in parallel with the disk surface of the optical disk 2 mounted on the disk table 12 using the second electromagnets 32a, 32b, 33a, 33b shown in FIG. In this case, a driving current in one direction is supplied to the second electromagnets 32a and 33b positioned diagonally, and a driving current in the other direction is supplied to the second electromagnets 32b and 33a. As a result, the second electromagnets 32a and 33b have different polarities from the opposing magnets 27a and 27b and generate an attractive force A, and the second electromagnets 32b and 33a have the same polarity as the opposing magnets 27a and 27b. The repulsive force R is generated. In the movable frame 22 to which the optical pickup unit 21 is attached, the elastic bodies 24 a and 24 b are deformed by the attractive force A and the repulsive force R, and rotate in one direction parallel to the disk surface of the optical disk 2. When the movable frame 22 is rotated in the direction opposite to that shown in FIG. 8, a driving current opposite to that in the above example may be supplied to the second electromagnets 32a, 32b, 33a, 33b. As a result, the optical pickup device 20 can rotate the objective lens 21a parallel to the disc surface of the optical disc 2.

  For example, for the purpose of tracking control of the objective lens 21a, the light beam emitted from the semiconductor laser may be split into 0-order light ± first-order light and more. Alternatively, a large number of light beams may be used from a large number of semiconductor lasers. In the example of FIG. 8, the objective lens 21a can be rotated in parallel with the disc surface of the optical disc 2, whereby the angle adjustment of the positions of the spots of the plurality of light beams can be performed, and the plurality of light beams can be adjusted. Can be accurately irradiated at a predetermined position.

  FIG. 9 shows a state in which the movable frame 22 is moved in parallel with the disk surface of the optical disk 2 mounted on the disk table 12 using the second electromagnets 32a, 32b, 33a, 33b shown in FIG. In this case, a driving current in one direction is supplied to the second electromagnets 32a and 33a located on one long side of the support frames 23a and 23b, and a driving current in the other direction is supplied to the second electromagnets 33b and 33b. . As a result, the second electromagnets 32a and 32a have different polarities from the opposing magnets 27a and 27b and generate an attractive force A, and the second electromagnets 32b and 33b have the same polarity as the opposing magnets 27a and 27b. The repulsive force R is generated. The movable frame 22 to which the optical pickup unit 21 is attached has the elastic bodies 24 a and 24 b deformed by the attractive force A and the repulsive force R, and translates in one direction parallel to the disk surface of the optical disk 2. When the movable frame 22 is moved in the direction opposite to that shown in FIG. 8, a driving current opposite to that in the above example may be supplied to the second electromagnets 32a, 32b, 33a, 33b. As a result, the optical pickup device 20 can move the objective lens 21a in parallel to the disc surface of the optical disc 2, specifically in a direction perpendicular to the recording track, together with the biaxial actuator 21b of the optical pickup portion 21. Alternatively, the tracking control of the objective lens 21a can be performed instead of the biaxial actuator 21b. Further, the second drive unit 30 can increase the stroke as compared with the biaxial actuator 21b. The high frequency vibration is compensated by the biaxial actuator 21b, and the low frequency vibration is compensated. The second driving unit 30 may compensate for this. Further, the eccentricity of the optical disk 2 can be effectively controlled by moving the objective lens 21a in a direction orthogonal to the recording track in synchronization with the rotation of the optical disk 2.

  FIG. 10 shows a state in which the movable frame 22 is moved in a direction perpendicular to the disk surface of the optical disk 2 mounted on the disk table 12 using the first electromagnets 28a, 28b, 29a, 29b shown in FIG. Show. In this case, a drive current that generates a repulsive force R is supplied to all of the first electromagnets 28a, 28b, 29a, and 29b. As a result, the movable frame 22 to which the optical pickup unit 21 is attached is deformed by the repulsive force R, and the elastic bodies 24 a and 24 b are deformed, so that the movable frame 22 moves vertically in the direction approaching the disk surface of the optical disk 2. When the movable frame 22 is moved in the direction opposite to that shown in FIG. 10, a driving current opposite to that in the above example may be supplied to all of the first electromagnets 28a, 28b, 29a, 29b. As a result, the optical pickup device 20 can move the objective lens 21a perpendicularly to the disc surface of the optical disc 2, specifically in the optical axis direction of the objective lens 21a, and the biaxial actuator 21b of the optical pickup unit 21. At the same time or in place of the biaxial actuator 21b, focusing control of the objective lens 21a can be performed. Further, when a vibration is applied such that the objective lens 21a collides with the optical disc 2, the movable frame 22 is vertically moved so that the objective lens 21a is separated from the disc surface of the optical disc 2, whereby the objective lens 21a and the optical disc 2 are moved. Collision with the disk surface can be prevented. In other words, the first drive unit 26 can increase the stroke as compared with the biaxial actuator 21b, and compensates for the high frequency vibration by the biaxial actuator 21b, and for the low frequency vibration. The first driving unit 26 may compensate for this.

  The recording medium may be any one of a read-only type, a write-once type, and a rewritable type optical disc, and may be an irregular optical disc that is not circular. The recording medium may be an existing first to third optical disc in addition to the above-described third optical disc on which high-density recording is performed, such as the Blu-ray disc.

1 is a perspective view of an optical disc apparatus to which the present invention is applied. It is a perspective view of the optical pick-up apparatus used for the said optical disk apparatus. It is a perspective view which shows the state by which the movable frame was supported by the support frame with the elastic body. It is a perspective view which shows the 1st drive part which moves a movable frame with respect to a support frame. It is a perspective view which shows the 2nd drive part which moves a movable frame with respect to a support frame. It is a perspective view which shows the state which inclined the movable frame to the radial direction of the optical disk with which the 1st electromagnet was mounted | worn with the disk table. It is a perspective view which shows the state which inclined the movable frame to the tangential direction of the optical disk with which the 1st electromagnet was mounted | worn with the disk table. It is a top view which shows the state which rotated the movable frame in parallel with the disk surface of the optical disk with which the 2nd electromagnet was mounted | worn with the disk table. It is a perspective view which shows the state which moved the movable frame in parallel with the disk surface of the optical disk with which the 2nd electromagnet was mounted | worn with the disk table. It is a perspective view which shows the state which moved the movable frame to the direction perpendicular | vertical to the disk surface of the optical disk with which the 1st electromagnet was mounted | worn with the disk table.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk apparatus, 2 Optical disk, 10 Disk rotation drive mechanism, 11 Spindle motor, 12 Disk table, 20 Optical pick-up apparatus, 21 Optical pick-up part, 21a Objective lens, 21b Two-axis actuator, 22 Movable frame, 23a, 23b Support frame, 24a, 24b Elastic body, 25a Locking piece, 26 First drive part, 27a, 27b Magnet, 28a, 28b, 29a, 29b First electromagnet, 30 Second drive part, 31a, 31b Support piece, 32a, 32b, 33a, 33b Second electromagnet, 36 feed mechanism

Claims (4)

A movable frame in which an optical pickup unit is disposed;
A support frame that supports the movable frame;
An elastic body that elastically supports the movable frame so that the movable frame is movable with respect to the support frame;
An optical disc comprising a magnet disposed on one of the movable frame and the support frame and an electromagnet disposed on the other and driving means for moving the movable frame relative to the support frame apparatus.   2. The optical disk apparatus according to claim 1, wherein the driving means includes a first driving unit that generates a driving force in a direction perpendicular to a disk surface of the optical disk.   2. The optical disk apparatus according to claim 1, wherein the driving means includes a second driving unit that generates a driving force in a direction parallel to a disk surface of the optical disk. 2. The optical disc apparatus according to claim 1, wherein the movable frame is supported by the support frame through the elastic body so as to be orthogonal to the radial direction of the optical disc.

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