JP3883187B2 - Optical pickup feeder - Google Patents

Description

[0001]
The present invention, CD-ROM, CD-R , CD-RW, is applied to an optical disk drive such as a DVD, it relates an optical pickup device in the optical pickup feeding equipment for moving in the radial direction of the optical disk.
[0002]
[Prior art]
FIG. 6 is a perspective view showing a schematic configuration of a conventional optical pickup feeding device, wherein 1 is an optical pickup device that detects light reflected by irradiating light on an optical disc, 2 is a guide shaft that supports the optical pickup device 1, 3 Indicates a lead screw having a helical thread groove 3 a formed on the surface thereof, and 4 indicates a drive motor for rotating the lead screw 3.
[0003]
Two guide shafts 2 and 2 and a lead screw 3 are arranged in parallel on a chassis (not shown), and the optical pickup 1 is slidably installed along the guide shafts 2 and 2. Along with a drive motor 4 and a disc motor provided with a turntable for placing an optical disc (not shown), it is installed on a chassis (not shown).
[0004]
Reference numeral 5 denotes a rack body that is fixed to the optical pickup device 1 and transmits the rotation of the lead screw 3 to the optical pickup device 1. The rack body 5 connects the fixing portion 6 that is fixed to the optical pickup device 1, the rack portion 8 that has a tooth portion 7 that meshes with the thread groove 3 a of the lead screw 3, and the fixing portion 6 and the rack portion 8. The fixing portion 6 and the rack portion 8 are arranged to face each other with a predetermined interval, and the bottom portion of the fixing portion 6 and the rack portion 8 is connected by the connecting portion 9. The rack body 5 is made of resin, and the fixed portion 6, the rack portion 8, and the connecting portion 9 are formed by integral molding. Of these, the connecting portion 9 is formed thin so as to function as a leaf spring, and the rack portion 8 can be swung in the direction of approaching and detaching from the lead screw 3 by the connecting portion 9.
[0005]
Reference numeral 10 denotes a biasing spring that is provided between the fixed portion 6 and the rack portion 8 and presses the rack portion 8 toward the lead screw 3. The rack portion 8 is always pressed against the lead screw 3 by the pressing force of the biasing spring 10.
[0006]
Then, the lead screw 3 is rotated by the rotation of the drive motor 4, and the rack body 5 is moved along the lead screw 3 along with the rotation of the drive motor 4, whereby the optical pickup device 1 is moved in the radial direction of the optical disc (not shown). When the drive motor 4 rotates when the optical pickup device 1 is positioned at the innermost or outermost periphery of the optical disk (not shown), the urging spring 10 is compressed, and the tooth portion 7 can get over the screw groove 3a, so that it is caught. The phenomenon can be prevented.
[0007]
As this type of conventional technology, there is an optical pickup feeding device described in, for example, Japanese Patent Application Laid-Open No. 11-144408.
[0008]
According to the optical pickup feeding device described in this publication, the rack portion provided with the tooth portion that engages with the thread groove portion of the lead screw is movable in the direction of approaching and detaching from the lead screw, and faces the chassis constituting the traverse mechanism. A stopper is provided on the rack portion. The distance between the chassis and the stopper in a state where the screw groove portion and the tooth portion are engaged is set so that the stopper and the chassis come into contact only when the tooth portion gets over the screw groove portion. For this reason, when an external force such as an impact is applied, and the optical pickup moves when the tooth portion gets over the thread groove portion, the stopper and the chassis come into contact with each other, so that a frictional force is generated at the contact portion. Since the acceleration of movement of the optical pickup is reduced by the frictional force, even if the optical pickup collides with another component, the impact can be reduced.
[0009]
[Problems to be solved by the invention]
An optical pickup device mounted on a general optical disk drive device may move due to strong external force such as impact or vibration when dropped. When the amount of movement is large, the optical pickup device collides with other parts, and in the worst case, the optical pickup device fails. This phenomenon occurs because a threaded groove of a lead screw for moving the optical pickup device is provided in a member joined to the optical pickup device, and a tooth portion that engages with the threaded groove gets over. Therefore, it is possible to avoid the situation where the optical pickup device collides with other parts by simply restricting the movement of the tooth portion so that the tooth portion does not get over the screw groove. When it is located on the circumference or outermost circumference, the tooth portion is bitten into the thread groove.
[0010]
In particular, in the apparatus shown in FIG. 6, when a strong impact force such as dropping is applied, the tooth portion 7 gets over the screw groove 3a and the optical pickup device 1 moves, and in the worst case, the optical pickup device. No. 1 may collide with other parts such as a chassis (not shown) to cause a failure.
[0011]
Further, in the optical pickup feeding device described in Japanese Patent Application Laid-Open No. 11-144408, it is necessary to bring the stopper provided on the rack portion into contact with the chassis, so that it may be difficult to assemble in terms of layout. It is done.
[0012]
The present invention solves such problems, and even if the optical pickup device collides with other parts, the impact received by the optical pickup device at that time is reduced, and the optical pickup device fails due to the collision. An object of the present invention is to provide an optical pickup feeding device that can suppress the occurrence of the above.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is directed to a lead screw having a thread groove formed spirally only in a predetermined region , a rack portion having a tooth portion meshing with the lead screw, and the rack portion. Is fixed to the optical pickup device so as to be able to approach and detach from the lead screw, an urging member that presses the rack portion against the lead screw, and the tooth portion within the predetermined region. A stopper that comes into contact with the lead screw when the screw groove portion is overcome, and transmits the rotation of the lead screw to the optical pickup device via the rack portion and the fixing portion to in the optical pickup feeding device for moving along the screw, the teeth at the boundary of the predetermined region is the Lee Upon reaching the area which is not formed of the screw groove of the screw, wherein the lead screw has a structure in which contact with the stopper in a rotatable state. By configuring in this way, an external force of strength such as impact is applied, the tooth part gets over the thread groove part, and when the optical pickup device moves, the stopper comes into contact with the lead screw, so that frictional force is generated there, Since the frictional force acts in the opposite direction to the movement acceleration of the optical pickup device, even if the optical pickup device collides with other parts, the impact at that time can be reduced. Moreover, since the lead screw can rotate even if the stopper is in contact with the lead screw, for example, the optical pickup device is located at the innermost or outermost periphery, and the tooth portion is formed with the thread groove of the lead screw. The biting phenomenon does not occur even when reaching a non-existing region.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol was attached | subjected about the member same as the member in the prior art shown in FIG. 6, and detailed description was abbreviate | omitted.
[0019]
FIG. 1 is a block diagram showing a schematic configuration of an optical disk apparatus having an optical pickup feeding apparatus according to the first embodiment of the present invention, and 20 is an optical pickup feeding apparatus for moving the optical pickup apparatus 1 in the radial direction of an optical disk 21. Is a disk motor that rotates the optical disk 21, 23 is a recording compensation circuit, 24 is an RF signal processing circuit, 25 is a modulation / demodulation circuit, 26 is a CPU, and 27 is a servo control circuit.
[0020]
The modulation / demodulation circuit 25 is connected to an audio circuit, an image compression / decompression circuit, or an interface for connection with a computer, and signals are input / output according to the purpose of use. The recording compensation circuit 23 includes a circuit that performs laser modulation using a recording signal. The RF signal processing circuit 24 includes a circuit that shapes the waveform of the read signal. The servo control circuit 27 detects an error component such as a tracking error signal or a focus error signal from the read signal and feeds it back to the optical pickup device 1 or the disk motor 22 to perform servo control so as to eliminate the error component. This servo control includes focus servo, tracking servo, and pickup feed servo. As the pickup feeding device 20, a feed screw method, a rack and pinion method, a linear motor method, and the like are known.
[0021]
Usually, a tracking error signal is used for the pickup feed servo. When the tracking error signal exceeds a certain value, a current is passed through the drive motor 4 (see FIG. 6) to rotate the drive motor 4. The entire pickup apparatus 1 moves in the radial direction of the optical disc 21 by the rotation of the drive motor 4. The current to the drive motor 4 stops flowing when the tracking error signal becomes smaller than a certain value, and the rotation of the drive motor 4 is stopped. At the time of access, a positive or negative constant current is supplied to the drive motor 4 without using a pickup feed servo loop, and the optical pickup device 1 is moved at high speed from the inner periphery to the outer periphery of the optical disc 21 or in the opposite direction. . By accessing the zero-crossing point of the tracking error signal during this period, an access is made to near the intended destination. When it reaches the vicinity of the destination, the pickup feed servo is operated to reproduce the signal, calculate the deviation from the target position, and again perform feed or return feed by counting the number of tracks or track jump to access the target position.
[0022]
The optical disk apparatus shown in FIG. 1 is a recording / reproducing drive apparatus, but may be a reproducing drive apparatus in which the recording compensation circuit 23 is omitted.
[0023]
FIG. 2 is a perspective view showing a schematic configuration of the optical pickup feeding apparatus according to the first embodiment of the present invention, and 15 denotes a stopper. The stopper 15 extends in an L shape from the top of the rack portion 8, and when the rack body 5 is installed, both sides of the lead screw 3 are surrounded by the rack portion 8 and the stopper 15.
[0024]
FIG. 3 is a side view showing the configuration around the lead screw in FIG. 1. Normally, the tooth portion 7 provided in the rack portion 8 and the screw groove 3 a are in mesh with each other by the biasing force of the biasing spring 10. A gap x is formed between the surface of the stopper 15 facing the rack portion 8 and the portion of the lead screw 3 opposite to the toothed portion of the tooth portion 7. The rack body 5 is made of resin, and the fixed portion 6, the rack portion 8, the connecting portion 9, and the stopper 15 are formed by integral molding.
[0025]
As shown in FIG. 3, when the tooth portion 7 is engaged with the thread groove 3 a of the lead screw 3, the stopper 15 has a gap x with the lead screw 3 and is not in contact with the lead screw 3. As shown in FIG. 4, the gap x is set so that the stopper 15 comes into contact with the lead screw 3 when the tooth portion 7 gets over the screw groove 3 a.
[0026]
When an impact such as a drop is applied and the tooth portion 7 gets over the screw groove 3a, the stopper 15 comes into contact with the lead screw 3, so that even if the optical pickup device 1 moves, the optical pickup device 1 The acceleration of the optical pickup device 1 decreases due to the frictional force acting in the direction opposite to the moving direction. For this reason, since the amount of movement of the optical pickup device 1 decreases, the probability that the optical pickup device 1 collides with other parts such as a part of a chassis (not shown) decreases, and by any chance the optical pickup device 1 collides with other parts. Even if a situation occurs, the impact can be reduced, and the failure occurrence rate of the optical pickup device 1 due to the impact can be suppressed. Further, even if the stopper 15 is in contact with the lead screw 3, the lead screw 3 can rotate. Therefore, even if the optical pickup device 1 is at the innermost circumferential position or the outermost circumferential position, the biting phenomenon does not occur.
[0027]
According to the present embodiment, the friction force between the stopper 15 and the lead screw 3 suppresses the acceleration of the optical pickup device 1 when receiving an impact, so that the stopper 15 contacts the lead screw 3. It is desirable that the surface has a high dynamic friction coefficient. In this case, for example, the stopper 15 may be made of a material having a high dynamic friction coefficient, or the contact surface may be roughened. Further, by obtaining a large frictional force, the failure rate of the optical pickup device 1 due to impact can be further reduced.
[0028]
FIG. 5 is a side view showing the configuration around the lead screw of the optical pickup feeder in the second embodiment of the present invention, and 16 shows a rubber sheet. In the second embodiment, a rubber sheet 16 is affixed to the contact surface of the stopper 15 in the first embodiment shown in FIG. 3 with the lead screw 3. In the normal state, the surface of the lead screw 3 and the rubber sheet 16 is used. A gap x is formed between the two.
[0029]
With this configuration, the rubber sheet 7 has a high dynamic friction coefficient, so that a larger frictional force can be obtained between the stopper 15 and the lead screw 3. Moreover, since the fixing method of the rubber sheet 16 to the stopper 15 is sticking, the assemblability is improved.
[0030]
【The invention's effect】
According to the present invention configured as described above, when a strong external force such as an impact is applied, the tooth portion gets over the screw groove portion, and the optical pickup device moves, the stopper comes into contact with the lead screw. A friction force acting in the opposite direction to the movement acceleration of the optical pickup device is generated at the contact part, so even if the optical pickup device collides with other parts, the impact at that time can be reduced Thus, the occurrence of failure of the optical pickup device due to the collision can be suppressed. In addition, when the optical pickup device is located on the innermost or outermost periphery and the tooth portion reaches the area where the screw groove portion of the lead screw is not formed , the lead screw rotates even if the stopper is in contact with the lead screw. Since it is possible, the biting phenomenon does not occur.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of an optical disc apparatus having an optical pickup feeding device according to a first embodiment of the present invention. FIG. 2 is a perspective view showing a schematic configuration of an optical pickup feeding device according to a first embodiment of the present invention. 3 is a side view showing the configuration around the lead screw in FIG. 1. FIG. 4 is a configuration around the lead screw in FIG. 3 when an impact is applied to the optical pickup device and the tooth portion gets over the thread groove. FIG. 5 is a side view showing a configuration around a lead screw of an optical pickup feeding device in a second embodiment of the present invention. FIG. 6 is a perspective view showing a schematic configuration of a conventional optical pickup feeding device. Explanation】
DESCRIPTION OF SYMBOLS 1 Optical pick-up apparatus 2 Guide shaft 3 Lead screw 3a Thread groove 4 Drive motor 5 Rack body 6 Fixing part 7 Tooth part 8 Rack part 9 Connection part 10 Energizing spring 15 Stopper 16 Rubber sheet 20 Optical pick-up feeder 21 Optical disk 22 Disc motor 23 Recording compensation circuit 24 RF signal processing circuit 25 Modulation / demodulation circuit 26 CPU
27 Servo control circuit

Claims (1)

A lead screw having a thread groove formed spirally only in a predetermined region ; a rack portion having a tooth portion meshing with the lead screw; and supporting the rack portion so as to be close to and detachable from the lead screw; and A fixing portion joined to the optical pickup device, an urging member that presses the rack portion against the lead screw, and the tooth portion abuts on the lead screw when the tooth portion passes over the thread groove portion within the predetermined region. An optical pickup feeding device that includes a stopper and transmits the rotation of the lead screw to the optical pickup device via the rack portion and the fixed portion, and moves the optical pickup device along the lead screw;
The lead screw is configured to come into contact with the stopper in a rotatable state when the tooth portion reaches a region where the thread groove portion of the lead screw is not formed at the boundary of the predetermined region. Optical pickup feeding device.

Images