JP5287696B2 - Optical disk device - Google Patents

Description

  The present invention relates to an optical disc apparatus that reads and / or writes information on an optical disc that is a recording medium.

  An optical disk device reads and / or writes information by inserting an optical disk, which is a recording medium, and irradiating light onto an information recording surface of the optical disk. A conventional optical disc apparatus will be described with reference to the drawings. FIG. 7 is a schematic plan view of a conventional optical disc apparatus. In the optical disc apparatus, an optical pickup 93 is supported by a pair of guide shafts 94, 94 provided in the traverse chassis 91, and is guided by the guide shafts 94, 94 to approach and separate from the turntable 92.

  The optical pickup 93 includes a rack piece 934 that meshes with a lead screw 951 that is rotatably supported by the traverse chassis 91, and the lead screw 951 is rotationally driven by a drive motor 952 that is fixed to the traverse chassis 91. The rack piece 934 is sent to the lead screw 951, and the optical pickup 93 is guided by the guide shafts 94, 94 to approach / separate the turntable 92. (Refer to Unexamined-Japanese-Patent No. 2000-156054, 2007-234108 etc.).

  In recent years, optical disc apparatuses can read and / or write information (hereinafter sometimes referred to as reading) on different types of optical discs such as CDs, DVDs, and BDs (Blu-ray discs). When reading or the like from a different optical disc, it is necessary to determine the type of the optical disc inserted into the optical disc apparatus. An optical disk is usually provided with an area where information unique to the disk called a Burst Cutting Area (BCA area) is written in the innermost circumference, and the optical disk inserted by reading the information in the BCA area. Can be discriminated.

  The BCA area is provided in the same range regardless of the optical disk, and the BCA of the optical disk placed on the turntable 92 is accurately controlled by controlling the position of the optical pickup 93 with respect to the optical disk (turntable 92). The information written in the area can be read accurately. In the optical disk device, in order to control the position of the optical pickup 93, it is necessary to detect the initial position of the optical pickup 93. In many optical disc apparatuses, the initial position is set to the stroke end of the optical pickup 93 (the one closer to or farther from the turntable 92).

  In the optical disc apparatus, immediately after the power is turned on or immediately after a new optical disc is inserted, the optical pickup 93 is moved to the initial position of the stroke end, and position control is performed using that position as the origin. As shown in FIG. 7, the traverse chassis 91 is provided with an optical pickup detection means 96 including a limit switch, a proximity switch, an optical sensor or the like at the stroke end. When the optical pickup 93 is moved to the stroke end and the optical pickup detection means 96 detects the optical pickup 93, the drive motor 952 is stopped. Thereby, the initial position is set.

  In addition, there is a method of adjusting the initial position using the feature of the stepping motor which is the drive motor 952. The optical pickup 93 is moved to the stroke end (here, farther from the turntable 92) and brought into contact with the traverse chassis 91. Since a pulse signal is input to the drive motor 952 and the rack piece 934 is stopped even if a force is generated to rotate the lead screw 951, the drive motor 952 is forcibly stopped. At this time, the drive motor 952 is in a so-called step-out state in which the pulse signal is input but does not move. It is detected that the optical pickup 93 has moved to the initial position when the drive motor 952 is in a step-out state (see Japanese Patent Application Laid-Open No. 2007-265525).

  With this configuration, it is possible to omit the optical pickup detection means 96 configured by a switch for detecting the initial position of the optical pickup 93, a substrate connected to the switch, wiring, and the like. Further, it is not necessary to provide a mounting area for the switch, the substrate, the wiring, and the like, and the size can be reduced accordingly.

JP 2007-265525 A

  The rack piece 934 is attached to the optical pickup 93 via an elastic member (plate spring), and is biased in a direction to be pressed against the lead screw 951. When the optical pickup 93 reaches the stroke end, the rack piece 934 applies a force to the lead screw 951 to stop the lead screw 951. On the other hand, a pulse signal is input to the drive motor 952, and a force that continues to rotate is applied to the lead screw 951.

  If the rotational torque of the lead screw 951 by the drive motor 952 is greater than the moment generated by the force to stop the lead screw 951 of the rack piece 934, the claw of the rack piece 934 jumps out of the groove of the lead screw 951, so-called tooth Causes a jump. When tooth jump occurs, abnormal noise and vibration occur. Further, if tooth skipping continues, the initial position cannot be detected, and the position control of the optical pickup 93 may not be performed. Furthermore, the claw of the rack piece 934 may be scraped into the spiral groove of the lead screw 951, making it easier to skip teeth.

  In order to suppress the occurrence of tooth skipping, Japanese Patent Application Laid-Open No. 2007-265525 uses rack engagement amount adjusting means for reducing the engagement amount of the rack with the lead screw groove when the optical pickup reaches the stroke end. . However, in order to determine the position of the optical pickup, a meshing amount adjusting means must be provided, and the configuration of the optical disc apparatus becomes complicated.

  Accordingly, an object of the present invention is to provide an optical disc apparatus that can accurately control the position of the optical pickup without using a detecting means for detecting the initial position of the optical pickup.

  It is another object of the present invention to provide an optical disc apparatus that suppresses occurrence of abnormal noise, vibration, and the like due to tooth skipping when detecting the initial position of an optical pickup, and has high operation quality.

  When the inventor of the present invention detects the initial position of the optical pickup, the end of the rack opposite to the initial position comes into contact with the lead screw, and the rack claw is moved by rotating the contact point as a fulcrum. The knowledge that the lead screw skipped was obtained.

  Based on this knowledge, in order to achieve the above object, the present invention is arranged such that an optical pickup that slides in the radial direction of the optical disk and a shaft that is rotatable so that the axis is parallel to the sliding direction of the optical pickup. A lead screw, a drive motor that rotates the lead screw and is a stepping motor, a rack portion that is connected to the optical pickup via an elastic member and meshes with the lead screw, and a vicinity of a stroke end of the optical pickup And an optical disk device including a stopper that prevents the optical pickup from sliding, and at least a base portion on the opposite side of the stopper portion of the base portion on which the claw portion that meshes with the lead screw of the rack portion is formed. The end of the rack is in contact with the stopper, and the end of the rack on the stopper side is When biased in a direction out of the de-screw, it is characterized in that it is formed so as to be able to avoid contact with the lead screw.

  According to this configuration, even if a force acts so that the end portion on the initial position side is lifted to the rack portion by the impact of the optical pickup contacting the stopper and the rotational torque of the drive motor, Since the gap between the end of the base opposite to the initial position and the lead screw is open, it is possible to suppress contact between the lead screw and the end of the base opposite to the initial position. .

  As a result, the end of the base opposite to the initial position comes into contact with the lead screw, and the claw part of the rack part is prevented from falling off the lead screw and jumping out with the contact point as a fulcrum. Is possible.

  Thereby, it is possible to detect the initial position of the optical pickup and to control the position accurately and quickly. Moreover, it is possible to suppress the generation of abnormal noise and vibration due to tooth skipping. As a result, it is possible to provide an optical disc apparatus with high operation quality.

  In the above-described configuration, the base portion may include a step portion formed at the end opposite to the stopper on the surface facing the lead screw so as to increase the distance from the lead screw. The base portion may be a flat plate member, and a surface facing the lead screw may be formed so that a distance from the lead screw is constant.

  In the above-described configuration, the lead screw includes a right-handed spiral groove, the elastic member connects the optical pickup and the rack portion on the rear stage side of the lead screw, and the stopper is provided on the outer side of the optical disc. It may be arranged in the vicinity of the stroke end on the radial side.

  The said structure WHEREIN: The said claw part may be formed in the edge part on the opposite side to the said stopper of the said rack part.

  According to the present invention, it is possible to provide an optical disc apparatus capable of accurately controlling the position of the optical pickup without using a detection means for detecting the initial position of the optical pickup.

  In addition, according to the present invention, when detecting the initial position of the optical pickup, it is possible to suppress occurrence of abnormal noise, vibration, etc. due to tooth skipping, and to provide an optical disc apparatus with high operation quality.

1 is a schematic diagram of an optical disc apparatus according to the present invention. It is the top view to which the driving force transmission part of the optical disk apparatus shown in FIG. 1 was expanded. It is the figure seen from the guide shaft side of the driving force transmission part shown in FIG. It is a top view when an optical pick-up reaches the stroke end which is an initial position. It is the top view to which the rack part of the optical pick-up used for the optical disk device concerning this invention was expanded. FIG. 10 is an enlarged plan view of a rack portion of an optical pickup used in an optical disc apparatus of still another example according to the present invention. It is the schematic of the conventional optical disk apparatus.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of an optical disc apparatus according to the present invention. As shown in FIG. 1, an optical disc apparatus A includes a traverse chassis 1, a turntable 2 attached to the traverse chassis 1 for rotating the optical disc, and an optical pickup 3 for irradiating the optical disc rotated by the turntable 2 with laser light. And.

  The traverse chassis 1 is formed by cutting and bending a metal plate into a rectangular shape. The traverse chassis 1 is held by a main chassis (not shown) via a damper member 11. The damper member 11 is a member that alleviates transmission of vibrations and shocks from the main chassis to the traverse chassis 1 or vice versa, and is formed of an elastically deformable material. The traverse chassis 1 has a rectangular opening 10 in the center. In addition, although the traverse chassis 1 has illustrated what was formed by cutting and bending a metal plate, it is not limited to it and may be a resin molded body.

  A turntable 2 is attached to the traverse chassis 1 near the center of one short side of the opening 10 on the front side. The turntable 2 is fixed to the tip of the output shaft of a motor (not shown). As the motor rotates, the turntable 2 rotates. The turntable 2 includes a placement portion 21 for placing an optical disc, and a convex portion 22 that passes through an opening formed in the center of the optical disc. The turntable 2 is configured to sandwich the optical disk with a clamper (not shown).

  In the traverse chassis 1, two guide shafts 4, which are a main shaft 41 for guiding the optical pickup 3 and a sub shaft 42, are arranged in parallel. Both ends of the main shaft 41 and the sub shaft 42 are supported by a shaft support portion 6 provided in the traverse chassis 1. The guide shaft 4 (41, 42) is arranged so as to cross the opening 10 in the longitudinal direction.

  As shown in FIG. 1, the optical pickup 3 holds a pickup base 31, a laser optical system including an objective lens 32 disposed to face the information recording surface of the optical disc, and the objective lens 32, and provides a track direction and a focus direction. And an objective lens holder 33 that moves to the center.

  The pickup base 31 has a bearing portion 311 that fits on one guide shaft 4 (main shaft 41) and an engagement portion 312 that engages the other guide shaft 4 (sub shaft 42). The bearing portion 311 is fitted in the main shaft 41 with little play, and the engagement portion 312 is partially open and is engaged with the other guide shaft 42 with much play.

  The optical pickup 3 is slid so as to approach and separate from the turntable 2 by a drive mechanism provided in the traverse chassis 1. As shown in FIG. 1, the drive mechanism includes a lead screw 51 rotatably supported on the opposite side of the sub shaft 42 across the main shaft 41 of the traverse chassis 1, and a lead screw 51 fixed to the traverse chassis 1. And a drive motor 52 for rotationally driving the motor.

  The lead screw 51 has a right-handed spiral groove 510 formed on the outer peripheral surface thereof, and is supported by the traverse chassis 1 so as to be parallel to the guide shaft 4 (41, 42). The drive motor 52 is a stepping motor. The drive motor 52 is connected to a control device (not shown) and is driven when a drive pulse signal is input from the control device.

  In order to transmit the rotation of the lead screw 51 to the optical pickup 3, the optical pickup 3 is provided with a driving force transmission unit. Details of the driving force transmission unit provided in the optical pickup 3 will be described with reference to the drawings. 2 is an enlarged plan view of the driving force transmission unit of the optical disc apparatus shown in FIG. 1, and FIG. 3 is a view of the driving force transmission unit of the optical disc device shown in FIG. 2 as viewed from the guide shaft side.

  As shown in FIG. 2, the driving force transmission portion includes a convex portion 71 projecting from the pickup base 1 in a direction orthogonal to the guide shaft 4 (41), a rack portion 72 to which the driving force is transmitted from the lead screw 51, A leaf spring portion 73 that integrally connects the convex portion 71 and the rack portion 72 is provided.

  The convex portion 71, the rack portion 72, and the leaf spring portion 73 are an integrally molded body of resin, and the convex portion 71 is fixed to the pickup base 31 using a fastening tool such as a screw. Note that the pickup base 31 and the driving force transmission portion (entirely or at least the convex portion 71) may be integrally formed.

  The leaf spring portion 73 connects portions of the convex portion 71 and the rack portion 72 close to the traverse chassis 1. The convex portion 71 and the rack portion 72 have shapes that are difficult to deform, and the rack portion 72 moves in a direction approaching and separating from the lead screw 51 due to the elastic deformation of the leaf spring portion 73 substantially. Further, the leaf spring portion 73 connects the convex portion 71 and the rack portion 72 at two positions with a gap in the axial direction of the lead screw 51.

  The leaf spring portion 73 is a member having a spring property itself, and further, a coil spring 74 is disposed between the convex portion 71 and the rack portion 72 in order to strongly press the rack portion 72 against the lead screw 51. Yes. The coil spring 74 is compressed and attached. In addition, the coil spring 74 does not need to be provided when the rack part 72 can be strongly pressed by the leaf spring part 73 so as not to drop off the lead screw 51.

  Since the leaf spring portion 73 is formed with a surface parallel to the axis of the lead screw 51, the leaf spring portion 73 has high rigidity in the feeding direction of the optical pickup 3, that is, the axial direction of the lead screw 51. Thus, when the lead screw 51 is rotated and the driving force is transmitted to the rack portion 72, the shaft of the lead screw 51 is between the convex portion 71 and the rack portion 72, that is, between the optical pickup 3 and the rack portion 72. It is possible to move the optical pickup 3 with high accuracy because the positional deviation in the direction hardly occurs.

  The rack portion 72 is connected to and supported by the convex portion 71 by a leaf spring portion 73. By bending the leaf spring portion 73, the rack portion 72 swings between the convex portion 71 and the lead screw 51 around the leaf spring portion 73.

  The rack portion will be described in more detail with reference to the drawings. Note that the right side in FIG. 2 and the left side in FIG. 3 are the turntable side, that is, the center side of the optical disc. As shown in the drawing, the rack portion 72 includes a base 720 connected to the leaf spring portion 73, and a claw portion 721 that is formed integrally with the base 720 and that is a protrusion that meshes with the spiral groove 510 of the lead screw 51. ing.

  As shown in FIG. 3, the rack portion 72 is arranged side by side so that two claw portions 721 inclined in the clockwise direction in the drawing are parallel to each other. The direction of this inclination is determined by the turning direction of the spiral groove 510 of the lead screw 51 (right screw direction in this embodiment), and the angle and the interval between the claw portions 721 are determined by the pitch of the spiral groove 510. The claw portions 721 are arranged at intervals corresponding to the pitch of the spiral grooves 510 so that the claws 721 can mesh with the spiral grooves 510 of the lead screw 51. Further, the claw portion 721 has a shape that becomes narrower as it is away from the base portion 720 so that the side portion can come into contact with the valley portion of the spiral groove 510. When the lead screw 51 rotates, the claw portion 721 is pushed by the spiral groove 510, so that the optical pickup 3 is guided along the guide shaft 4 (41, 42) via the rack portion 72, the leaf spring portion 73, and the convex portion 71. Directional force acts.

  As shown in FIGS. 2 and 3, the base 720 is a flat plate-like member, and is closer to the end on the turntable 2 side of the surface on which the claw portion 721 is formed (away from the lead screw 51). As shown in FIG.

  Next, a method for detecting the initial position of the optical pickup 3 will be specifically described. FIG. 4 is a plan view when the optical pickup reaches the stroke end which is the initial position.

  The initial position of the optical pickup 3 will be described. As shown in FIG. 4, in the optical disc apparatus A, the initial position of the optical pickup 3 is set at the end opposite to the turntable 2. This is due to the shape of the spiral groove 510 of the lead screw 51 and the position of the leaf spring portion 73 of the driving force transmission portion. That is, when the lead screw 51 rotates so as to move the optical pickup 3 to the outer peripheral side of the optical disk, the claw portion 721 is pushed by the spiral groove 510 toward the leaf spring portion 73, and the claw portion 721 jumps away from the spiral groove 510. It is difficult to detect and the initial position can be detected stably.

  As shown in FIG. 4, the traverse chassis 1 is formed with a stopper 12 that contacts the optical pickup 3 when the optical pickup 3 moves to the stroke end. The stopper 12 has a shape protruding into the opening 10 so as to be in contact with the vicinity of the bearing portion 311 of the pickup base 31. In the following description, the detection of the initial position immediately after the optical disk apparatus is turned on will be described as an example. However, in addition to this, the initial position may be detected when a new optical disk is inserted.

  First, the claw part 721 of the rack part 72 is pushed by the spiral groove 510 by driving the drive motor 52 and rotating the lead screw 51. As a result, the optical pickup 3 moves to the opposite side of the turntable 2 along the guide shaft 4 (41, 42) (see FIG. 2).

  The optical pickup 3 moves to the stroke end on the outer peripheral side of the optical disk and comes into contact with the stopper 12. The optical pickup 3 stops and the rack portion 72 also stops. At this time, a pulse signal for driving is input to the driving motor 52, and the driving is continued. As a result, torque is applied to the lead screw 51 in a direction in which the lead screw 51 continues to rotate, the claw portion 721 is biased in the rotational direction by the spiral groove 510, and the rack portion 72 has a direction to follow the rotation of the lead screw 51 and A force acts toward the outer peripheral side of the optical disk in the axial direction of the lead screw 51.

  As shown in FIG. 4, when the optical pickup 3 reaches the stroke end on the outer peripheral side of the optical disc, the rack portion 72 acts in a direction in which the outer peripheral side of the optical disc is detached from the lead screw 51. The outer peripheral side moves away from the lead screw 51 around the side. In the driving force transmission portion provided in the conventional optical pickup, the end on the turntable 2 side contacts the lead screw and rotates around the contact point. Thus, by rotating about the contact point as a fulcrum, even when the moment due to the force with which the driving force transmission unit presses the lead screw is smaller than the rotational torque of the lead screw, the rack portion may come out of the lead screw.

  In the rack portion 72 of the optical disc apparatus according to the present invention, a step portion 722 is formed in the base portion 720. Thereby, it can suppress that the edge part of the base part 720 contacts the lead screw 51, and the rack part 72 rotates using the contact part as a fulcrum. As a result, when the optical pickup 3 moves to the stroke end on the outer peripheral side of the optical disc, it is possible to prevent the rack portion 72 from jumping out of the spiral groove 510 of the claw portion 721 and jumping out. .

  Further, by this, when the optical pickup 3 reaches the stroke end on the outer peripheral side of the optical disk, the lead screw 51 is pressed by the rack portion 72 and the drive of the drive motor 52 is stopped. At this time, a drive pulse signal is input to the drive motor 52, and the drive motor 52 steps out. By detecting the step-out of the drive motor 52, it is detected that the optical pickup 3 has moved to the initial position, and the position of the optical pickup 3 is controlled by the number of pulses input to the drive motor 52 with this position as the origin.

  Another embodiment of the present invention will be described with reference to the drawings. FIG. 5 is an enlarged plan view of a rack portion of an optical pickup used in another example of the optical disc apparatus according to the present invention. As shown in FIG. 5, the optical pickup 3 b includes a rack portion 75 instead of the rack portion 72. Except for the rack portion 75, the configuration is the same as that of the optical disc apparatus shown in FIG.

  As shown in FIG. 5, when the rack portion 75 engages the claw portion 751 with the lead screw 51, the tip end portion of the claw portion 751 contacts the lowest portion of the spiral groove 510 of the lead screw 51, and the base 750 is connected to the lead screw 51. It is far from 51.

  The distance between the base 750 and the lead screw 51 is that when the optical pickup 3b reaches the stroke end on the outer peripheral side of the optical disk, and the force that the end opposite to the turntable 2 is separated from the lead screw 51 acts on the rack 75. The end on the turntable 2 side is open to the extent that it does not contact the lead screw 51.

  In this way, the end on the turntable 2 side does not contact, so that the end on the opposite side of the turntable 2 is centered on the contact point between the end on the turntable 2 side and the lead screw as in the conventional optical pickup. It is possible to suppress the occurrence of so-called tooth jump, in which the end portion rotates in a direction away from the lead screw and the claw portion 751 of the rack portion 75 is detached from the spiral groove 510. Note that the detection of the initial position of the optical pickup 3b uses the step-out of the drive motor 52 as in the case of the optical pickup 3, and details thereof are omitted.

  By suppressing tooth jump, the initial position of the optical disk can be detected accurately and quickly, and the time required for the initial operation for reading the optical disk can be shortened accordingly.

  Another embodiment of the present invention will be described with reference to the drawings. FIG. 6 is an enlarged plan view of a rack portion of an optical pickup used in still another example of an optical disc apparatus according to the present invention. As shown in FIG. 6, the optical pickup 3 c includes a rack portion 76 instead of the rack portion 72. Except for the rack section 76, the configuration is the same as that of the optical disc apparatus shown in FIG. 2 and the like, and substantially the same portions are denoted by the same reference numerals.

  As shown in FIG. 6, the rack portion 76 has one of the claw portions 761 formed at the end portion on the turntable 2 side, and the end portion of the rack portion 76 on the turntable 2 side extends the side surface of the claw portion 761. It has become a slope.

  As described above, the end of the rack portion 76 on the turntable 2 side has a shape in which the side surface of the claw portion 761 is extended, so that when the optical pickup 3 comes into contact with the stopper 12, the turntable 2 of the rack portion 76. It can suppress that the edge part of a side contacts the lead screw 51. FIG. Thereby, it is possible to suppress the rack portion 76 from rotating around the contact point on the turntable 2 side and skipping teeth.

  The present invention can be used for an optical disc apparatus that detects an initial position of an optical pickup at the time of power-on or the like by detecting the stepping motor step-out by causing the optical pickup to reach the stroke end.

DESCRIPTION OF SYMBOLS 1 Traverse chassis 11 Damper member 12 Stopper 2 Turntable 3 Optical pick-up 31 Pickup base 32 Objective lens 33 Objective lens holder 4 Guide shaft 51 Lead screw 52 Drive motor 6 Shaft indication part 71 Convex part 72 Rack part 720 Base 721 Claw part 722 Step Part 73 Leaf spring part 74 Coil spring

Claims (3)

An optical pickup that slides in the radial direction of the optical disc;
A lead screw that is rotatably arranged so that its axis is parallel to the sliding direction of the optical pickup;
The lead screw is rotationally driven, and a drive motor that is a stepping motor;
A rack portion coupled to the optical pickup via an elastic member and meshing with the lead screw;
An optical disc device including a stopper disposed near a stroke end of the optical pickup and preventing the optical pickup from sliding;
At least an end portion of the base portion on the side opposite to the stopper where the claw portion that meshes with the lead screw of the rack portion is in contact with the stopper, and an end portion of the rack portion on the stopper side An optical disk apparatus comprising: a step portion that increases a distance from the lead screw so that contact with the lead screw can be avoided when biased in a direction away from the lead screw . An optical pickup that slides in the radial direction of the optical disc;
  A lead screw that is rotatably arranged so that its axis is parallel to the sliding direction of the optical pickup;
  The lead screw is rotationally driven, and a drive motor that is a stepping motor;
  A rack portion coupled to the optical pickup via an elastic member and meshing with the lead screw;
  An optical disc device including a stopper disposed near a stroke end of the optical pickup and preventing the optical pickup from sliding;
  At least an end portion of the base portion on the side opposite to the stopper where the claw portion that meshes with the lead screw of the rack portion is in contact with the stopper, and an end portion of the rack portion on the stopper side The claw portion is formed at the end opposite to the stopper so that contact with the lead screw can be avoided when urged in a direction away from the lead screw,
  An optical disc apparatus characterized in that an end portion of the rack portion opposite to the stopper is a slope extending from a side surface of the claw portion. The lead screw has a right-handed spiral groove;
The elastic member connects the optical pickup and the rack portion on the rear stage side of the lead screw,
The optical disk apparatus according to claim 1, wherein the stopper is disposed in the vicinity of a stroke end on the outer diameter side of the optical disk.

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