JP2007529840A - Device for fixing optical pickup unit of optical drive - Google Patents

Abstract

The present invention relates to an optical pickup unit, a linear drive motor, and an optical drive having a follower (12) coupled to the optical pickup unit and cooperatively engaged with the motor. The motor operation described above results in linear movement of the follower (12) and the optical pickup unit during normal operation. The preceding optical drive further has a stop member (26). The stop member (26) is arranged and configured to allow movement of the follower (12) by the stop member (26) and the locking means (18, 28a-28b) during normal operation of the optical drive. The movement of the follower (12) relative to the stop member (26) in the drive position is brought to a fixed position, the movement being restricted or prevented by the stop member (26).

Description

  The present invention generally relates to an optical drive that writes information to and / or reads data from an optical storage medium. Even more particularly, the invention relates to an apparatus for positioning an optical drive that writes information to an optical storage medium and / or an optical pickup unit of an optical drive that reads data from the optical storage medium. Examples of such storage media are, for example, CD-ROM, CD-R, CD-RW, DVD, and Blu-ray. In these examples, the optical storage medium has the shape of a disc.

  As is well known in the prior art, an optical disc has at least one track that can have written data. The disc can be implemented to be read-only. The disc is manufactured with data recorded in a track, and this data can only be read from the disc. However, writable optical discs that allow users to record data on the disc are also known. In this case, the disc is usually manufactured as an empty disc, ie a disc having a track structure but no data recorded in the track.

  Similarly, an optical disc drive can be designed as a read-only device, ie a device that can only read information from a recorded disc. However, optical disc drives can also be designed to write information onto a recordable disc track. However, in all cases, the optical disc drive has means for receiving the optical disc and rotating the optical disc at a predetermined rotational speed. The optical disc drive further includes an optical head having an optical beam generator or an optical pickup unit (OPU). The light beam generator is typically a laser that directs the light beam toward the surface of the rotating disk, receives the reflected beam reflected by the disk, and converts the received reflected beam into an electrical signal. Is.

  Therefore, the optical pickup unit includes a light beam generator, an optical system that directs the light beam toward the optical disc, a photodetector that converts light into an electrical signal, and reflected light that is received by the reflected light to the photodetector. It has an optical system that directs toward it. The optical system can focus the light beam on the track of the optical disc, and further can focus the reflected light beam on the photodetector. The optical system is movable along the optical axis (z direction) so as to compensate for changes in the length of the optical path. The servo system associated with this optical lens system is adapted to maintain the desired focus.

  The problem with optical pickups is that the photodetector must be very accurately positioned with respect to the light beam. The tolerance for the position of the photodetector in the z direction is on the order of about 100 μm. The tolerance in the direction perpendicular to the z direction (x direction is radial direction, y direction is track direction) is on the order of 10 μm. However, it is very difficult to ensure that this positioning accuracy is maintained for the lifetime of the optical pickup, given that the optical pickup can be subjected to inactive mechanical collisions or impacts. The collision or impact is caused, for example, by transporting or transporting the optical drive, so that the OPU can be struck and damaged by the optical drive mechanism.

  In recent years, pieces of cardboard or the like have been added to the optical drive mechanism during packaging for transportation to help limit the movement of the OPU during transportation. However, once this cardboard is installed at the console, it is permanently removed from the mechanism, the movement of the OPU is no longer restricted, and a strong impact at the console level can also damage the OPU.

  As described above, the OPU is movable along the optical axis (z direction) to compensate for changes in the length of the optical path. A servo system associated with the optical lens system is adapted to maintain the desired focus. Such servo systems typically include a stepping motor having a lead screw that is communicably coupled to the OPU follower. The OPU is attached to the follower so that movement of the OPU follower due to operation of the stepping motor results in corresponding movement of the OPU as desired. However, mechanical impacts or impacts applied to the optical drive can also cause damage to the stepper motor due to the excessive force created by the resulting OPU acceleration. Thus, any strong impact at the console level can damage the OPU and sledge motor.

  Applicants have invented an improved device. The present invention provides an optical pickup for an optical drive at a particular drive position to prevent collisions with each optical drive mechanism and to protect the stepper motor from impacts or collisions applied, for example, during transport or transportation of each device. It is intended to provide a device for positioning a unit.

  In accordance with the present invention, an apparatus for positioning an optical pickup unit of an optical drive at a predetermined drive position is provided. The apparatus includes a linear drive motor and a follower coupled to and cooperatively engaged with the preceding optical pickup unit, the operation of the motor being in normal operation. Provides linear movement of the follower and optical pickup unit. The foregoing apparatus has a stop member arranged and configured to limit the movement of the preceding follower during normal operation of the optical drive. The device further comprises locking means for providing movement to the fixed position of the follower relative to the preceding stop member at the aforementioned predetermined drive position, the movement being restricted or prevented by the stop member.

  In one embodiment of the invention, the motor has an elongated lead screw having a helical groove defining a thread along at least a portion of its overall length, and the follower has at least one protrusion that engages the groove. Thus, the operation of the motor results in the rotation of the lead screw and the corresponding linear movement of the follower. In one embodiment of the present invention, the follower has at least one protrusion that engages two respective longitudinally spaced portions of the preceding spiral groove.

  Beneficially, movement of the follower to the aforementioned fixed position is achieved by linear movement of the follower from the first fixed position to the second fixed position. Such linear movement is accomplished manually or by motor operation to provide corresponding rotation of the lead screw. In one embodiment of the invention, the lead screw is at least in the body portion of the lead screw between two adjacent longitudinally spaced portions of the helical groove defining the thread of the preceding lead screw. One intermediate groove is provided. At least one protrusion is adapted to engage the intermediate groove to provide a fixed position. If the follower has two protrusions, the lead screw has two respective intermediate grooves with which each two protrusions are engaged to provide a fixed position.

  Therefore, by fixing the OPU in the fixed position, collisions with the mechanism are prevented, and in addition, a linear drive motor, for example a stepping motor, is protected.

  In one embodiment of the present invention, the motor is mounted on a bracket having a base plate, and a stop member projects upward from the plane of the base plate. The stop member may be formed integrally with the base plate. The bracket may have an end wall spaced from the stop member so that the follower is trapped between the end wall and the stop member in a fixed position.

  In one embodiment of the invention, the locking means is such that the movement of the follower relative to the stop member is in a direction that is substantially perpendicular to the direction of linear movement of the follower during normal operation to provide the aforementioned fixed position. Placed.

  The invention also extends to an optical drive having a positioning device.

  These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

  An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings.

  It is an object of the present invention to provide an improved arrangement in which the optical pickup unit of the optical drive can be manually or electrically fixed at the specific drive position desired.

  Referring to 1a and FIG. 1b in the first example, a positioning device according to one embodiment according to the present invention is communicatively coupled to a lead screw 14 of a stepping motor 16 using follower teeth 18. The optical pickup unit OPU10 is mounted on the follower mechanism 12. The teeth 18 engage in grooves 20 that define the thread of the lead screw 14. As will be apparent to those skilled in the art, since the lead screw 14 is coupled to the rotor (not shown) of the motor 16, operation of the motor 16 causes the lead screw 14 to rotate. The movement is translated into a linear movement of the follower 12 and OPU 10 along the length of the lead screw 14. Thus, in the illustrated example, the rotation of the stepping motor in the counterclockwise direction (arrow B) is changed to a linear motion of the follower and OPU in the direction indicated by arrow A. The direction of the arrow A is hereinafter referred to as “regression (homing) direction”.

  Referring to FIG. 2, the motor 16 is mounted on an elongated bracket 22 having a base plate 23 and an end wall 24 perpendicular thereto, and the lead screw 14 extends from the motor 16 to the end wall 24 as shown. Extending along the length of The bracket 22 is provided with a stop member 26 near the end wall 24. The stop member 26 protrudes upward from the plane of the base plate 23 at a substantially right angle thereto. In this embodiment, the stop member 26 is formed integrally with the base plate 23 so that a substantially L-shaped structure can be defined, but this is not essential. The lead screw 14 is further provided with two intermediate grooves 28a, 28b in two adjacent body portions defined by the threads of the lead screw 14 as shown.

  Referring now to FIGS. 3a and 3b, the OPU 10 must return to the so-called “home position” to secure the OPU 10 for transport or transportation of the optical drive mechanism of which the OPU 10 is a part. To achieve this, the motor is operated in the counterclockwise direction (arrow B) by the application of an electrical pulse, and the last two adjacent grooves 20 in which the follower teeth 18 are defined by the threads of the lead screw 14. Until followed by movement of the follower 12 and the OPU 10 mounted thereon in the return direction. When the follower 12 contacts the end wall 24 of the motor bracket 22, the OPU 10 is considered to be in the “home position” as illustrated in FIGS. 3a and 3b. The regression procedure described above ends without mechanical slipping between the follower and the lead screw pitch. This can be achieved by reducing the current amplitude for the motor during the regression period. Due to the shape of the follower and its position relative to the motor bracket 22 and the depth of the groove 20 defined by the thread of the lead screw 13, the follower 12 protrudes upward from the base plate 23 of the bracket 22 during normal operation. It passes freely through the stop member 26 (see FIG. 3b). That is, when the follower 12 is in the normal position with respect to the lead screw 14, the follower 12 passes the stop member 26 and does not interfere with the sledge system.

  Referring to FIGS. 4a and 4b, as soon as the follower and OPU are in the home position, a “lock” command may be issued from the console (in response to a command from the user). Such a command causes the motor to further rotate a half turn counterclockwise, causing the follower teeth 18 to enter the intermediate grooves 28 a, 28 b in the lead screw 14. It will be appreciated by those skilled in the art that it is relatively easy to control the angular position of the stepper motor by applying precise step dimensions. The current applied to the motor must be higher than the current used to provide normal operation to provide the desired level of force to push the follower teeth 18 into the intermediate grooves 28a, 28b. Considering the fact that the depth of the intermediate grooves 28a, 28b is smaller than the depth of the groove 20 defined by the thread of the lead screw 14, the follower 12 is pushed in the direction of the OPU 10 as shown in FIG. And fixed by the stop member 26 in its new position. Therefore, in summary, to fix the OPU in the home position, the OPU follower is pushed toward the OPU by an intermediate groove in the motor lead screw, and the position of the new follower is fixed by a stop member protruding upward from the motor bracket Is done.

  To assist the OPU 10, the motor may continue to rotate in a counterclockwise direction for another half turn so that the follower teeth 18 return to their normal position in the groove 20 defined by the thread of the lead screw 14. Is done. Thereby, the follower 12 returns to the normal position relative to the motor bracket 22 so that its movement is not restricted by the stop member 26.

  Thus, the present invention provides a mechanism by which the OPU can be locked in a non-operating state, thereby reducing the risk of malfunction due to impact or collision. The inclusion of cardboard during the packaging process is eliminated. One of the main advantages of the above-described embodiments of the present invention is that the OPU can be locked or released by electrically controlling the stepping motor, i.e. by applying an appropriate current pulse to the motor. However, it will be appreciated that in other embodiments the OPU fixation procedure may be performed manually by hand.

  In the simplest construction, an embodiment of the present invention can be achieved by adding two new features to a known arrangement of stepping motors. That is, an intermediate groove in the lead screw of the motor and a stop member in or on the motor bracket. In some cases, the follower may be asked to consider new dimensions so that the follower can pass through the stop member during normal operation. Also, additional algorithms may be sought in the control system if it is desired to perform a lock / unlock procedure, which can be performed by electrical control of the angular position of the stepper motor.

  One embodiment of the invention has been described above by way of example only, and modifications and changes may be made to the embodiment described above without departing from the scope of the invention as defined by the appended claims. It will be apparent to those skilled in the art. Moreover, in the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word “comprising” does not exclude the presence of elements or steps other than those listed in a claim. The singular form does not exclude the plural. The present invention may be implemented using hardware having a plurality of different elements and using a suitably programmed computer. In the device claim enumerating several means, several of these means can be embodied by one and the same item of hardware. The fact that measures are listed in mutually different independent claims does not indicate that a combination of these measures cannot be used to advantage.

1 is a schematic plan view of an optical drive mechanism having a positioning device according to an embodiment of the present invention. FIG. 1b is a schematic perspective view of the mechanism in FIG. 1 b is a perspective side view of a motor unit for use in the mechanism in FIG. FIG. 2 is a schematic plan view of the mechanism in FIG. FIG. 2b is a schematic perspective view of the mechanism in FIG. 2a. FIG. 1b is a schematic plan view of the mechanism in FIG. 1a when the follower is locked in the “home” position. FIG. 4b is a schematic perspective view of the mechanism in FIG. 4a.

Claims (10)

An apparatus for positioning an optical pickup unit (10) of an optical drive at a predetermined drive position,
A linear drive motor (16),
・ Follower (12)
A stop member (26);
The locking means (16, 18, 28a-28b) and
The follower is coupled to the optical pick-up unit (10) and cooperatively engaged with the motor (16), so that the operation of the motor (16) is the follower (12) during normal operation. ) And the linear movement of the optical pickup unit (10),
The stop member is arranged and configured such that movement of the follower (12) is enabled by the stop member (26) during normal operation of the optical drive;
The locking means provides movement of the follower (12) to a fixed position relative to the stop member (26) in the predetermined drive position, the movement being restricted or prevented by the stop member;
apparatus. The motor (16) has an elongated lead screw (14) that has a helical groove (29) defining a thread along at least a portion of its length;
The follower (12) has at least one protrusion (18) that engages the groove (20), so that the operation of the motor (16) is dependent on the rotation of the lead screw (14) and the follower ( 12) resulting in a corresponding linear motion of
The apparatus of claim 1. The lead screw (14) includes at least one intermediate groove (28a, 28b) between two adjacent longitudinally spaced portions of the spiral groove (20), the lead screw ( 14) provided in the main body part,
The apparatus of claim 2. The motor (16) is mounted on a bracket (22) having a base plate (23), and the stop member (26) protrudes upward from the plane of the base plate (23).
The apparatus of claim 1. The stop member is formed integrally with the base plate (23).
The apparatus of claim 4. The bracket (22) has an end wall (24) spaced from the stop member, and in the fixed position, the follower (12) is connected to the end wall (24) and the stop member (26). Trapped between),
The apparatus of claim 4. The locking means is substantially perpendicular to the direction of linear movement (A) of the follower (12) during normal operation so that the movement of the follower (12) relative to the stop member (26) is to provide the fixed position. Arranged and configured to be in a certain direction,
The apparatus of claim 1. Movement of the follower to the fixed position is effected by a linear movement of the follower (12) from a first position to a second fixed position;
The apparatus of claim 1. Movement of the follower (12) to and from the fixed position is effected by electrical control of the motor (16),
The apparatus of claim 1. An optical drive,
An optical pickup unit (10);
A linear drive motor (16),
・ Follower (12)
A stop member (26);
The locking means (16, 18, 28a-28b) and
The follower is coupled to the optical pick-up unit (10) and cooperatively engaged with the motor (16), so that the operation of the motor (16) is the follower (12) during normal operation. ) And the linear movement of the optical pickup unit (10),
The stop member is arranged and configured such that movement of the follower (12) is enabled by the stop member (26) during normal operation of the optical drive;
The locking means provides movement of the follower (12) to a fixed position relative to the stop member (26) in the predetermined drive position, the movement being restricted or prevented by the stop member;
optical drive.

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