JP3336901B2 - Optical pickup feed mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup feeding mechanism which can accurately guide an optical pickup for scanning an optical disk or a magneto-optical disk to a target track in a short time.

[0002]

2. Description of the Related Art A conventional optical disk apparatus for recording and reproducing information signals of an optical disk having a concentric or spiral recording area formed on the surface of a disk formed of a transparent resin or the like is known. A rotation driving device that holds the optical disk and rotates at a constant linear velocity or a constant angular velocity, emits a laser beam, focuses the light on the recording area of the optical disk via an objective lens, and reflects the reflected light from the recording area. The optical pickup device includes a detector that focuses and further detects a converged reflected light, a driving device that drives the optical pickup from the inner periphery to the outer periphery, and the like.

A conventional optical disk device is, for example, shown in FIGS.
As shown in FIG. 3, a chucking pulley 2 with a built-in yoke 3 for detachably mounting an optical disk 6 and a turntable 5 with a built-in magnet 4 directly connected to a spindle motor 7.
And a spindle motor 7 disposed inside an optical pickup 8 for driving the optical disk 6 to rotate, constitutes a rotation drive system for driving the optical disk 6 to rotate. An optical pickup 8 which emits a laser beam, focuses the light on the recording area of the optical disk 6 via an objective lens, focuses the reflected light from the recording area, and further incorporates a detector for detecting the converged reflected light. Are guided by the rail 9 fixed to the chassis 14 by the rotation power of the feed motor 13, and can be moved in a direction parallel to the radial direction of the optical disk 6. A signal processing circuit 18 for processing a reproduction signal and an error signal from the optical pickup 8, a focus tracking drive circuit 20, or the feed motor 1
3. A feed motor drive circuit 22 for driving the spindle motor 3 and a spindle motor drive circuit 21 for rotating the spindle motor 7
Are provided in the control circuit unit 17 together with the system computer 19 for controlling various operations.

When the optical disk 6 is mounted on the turntable 5 by an optical disk loading / unloading device (not shown), the feed motor drive circuit 22 is operated by a command from the system computer 19, and the feed motor 13 is driven to rotate. At this time, the rotation of the first gear 10 attached to the feed motor 13 is reduced by the second gear 11 and the third gear 12 and transmitted to the rack gear 8 a formed on the side surface of the carriage 8 b supporting the optical pickup 8. Is done. As a result, the optical pickup 8 moves along the rail 9 toward the innermost circumference. When the optical pickup 8 reaches the innermost circumference, the carriage 8b contacts the stopper of the chassis 14, and the optical pickup 8 stops moving. In addition, since the system computer 19 controls the feed motor drive circuit 22, the drive voltage applied to the feed motor 13 disappears after a certain period of time. At the same time, a laser beam is emitted from the optical pickup 8, a focus search is performed, and a focus servo is operated. In this state, the spindle motor 7 is driven to rotate. The optical disk 6 is mounted on a turntable 5 with a built-in magnet 4 directly connected to a shaft of a spindle motor 7, and is driven to rotate while being locked by a chucking pulley 2 with a built-in yoke 3.

When the optical disk 6 starts to rotate, a tracking servo operates, and while the feed motor 13 is operated little by little, the information signal of the optical disk 6 in which the spiral recording area is formed is traced. At this time, the spindle motor drive circuit 21 controls the rotation of the spindle motor 7 so as to obtain a constant linear velocity, and the TOC (Table Of Table) recorded in the innermost lead-in area of the optical disc 6 is controlled.
An information signal called “Contents” that summarizes the contents of a record is read. When the reading of the TOC is completed, the optical pickup 8 is moved to the position of the start address of the program area by the above control and stands by at that position.

Thereafter, when a reproduction command is input by a command input from an external computer, the system computer 19 instructs a track jump to a head address at which reproduction is started. In this track jump operation, the tracking servo is released while the spindle motor 7 is decelerated or accelerated so that the rotation speed of the optical disk 6 becomes the rotation speed of the reproduction start address while the focus servo is operated, and the feed motor is driven. The rotation of the feed motor 13 is driven by the circuit 22 to move the optical pickup 8 along the rail 9 toward the reproduction start address. In this case, a tracking error signal obtained by releasing the tracking servo is transmitted to the system computer 1.
9 until the number of tracks reaches the number of tracks up to the start address at which reproduction is started.

When the count value of the tracking error signal matches the number of tracks up to the head address at which reproduction starts, the drive of the feed motor 13 is stopped and the optical pickup 8 is stopped. At the same time as the stop of the optical pickup 8, the tracking servo is operated to trace the information signal of the optical disk 6 in which the spiral recording area is formed, and it is checked whether or not the sub-code is the head address at which the reproduction is started. If not, repeat the track jump,
The subcode is read, and it is checked whether or not it is the start address to start reproduction. Here, when the start address is the start address of the reproduction, the information signal of the optical disk 6 on which the spiral recording area is formed is traced while controlling the rotation of the spindle motor 7 so as to obtain a constant linear velocity. Then, the optical disk 6 is reproduced and stopped. Such a track jump and a reproducing operation are repeatedly performed in accordance with a command from an external computer.
Is accessed.

[0008]

In the above-mentioned conventional optical pickup feeding mechanism, it is necessary to make the track jump as fast as possible in order to realize high-speed access. For this reason, a gear mechanism from the feed motor 13 to the rack gear 8a, that is, a high geared reduction ratio in which the reduction ratio of the gear train including the first gear 10, the second gear 11, and the third gear 12 is made as small as possible has been adopted. However,
When a high geared reduction ratio is employed, the stop position of the feed motor 13 may be biased due to cogging of the feed motor 13 which has not been a problem at the time of a precision track jump of about 100 tracks or less. Such a deviation of the stop position may cause a track that cannot be stopped after the track jump, or may require repeated track jumps to the target track, resulting in excessive access time. Furthermore, in the tracing (reproducing) operation of the recorded information of the optical disk 6 after the track jump, the sound motor skips the track due to the sudden movement of the optical pickup 8 due to the cogging of the feed motor 13, causing a skipping of sound or a loss of data. Therefore, even if the track jump speed is increased for the purpose of high-speed access, the feed motor 1
The method of extremely reducing the reduction ratio of the gear train composed of the first gear 10, the second gear 11, the third gear 12, and the rack gear 8a attached to the gear 3 and making the gear train high-geared is dangerous, There was a problem that high-speed access naturally had limitations.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to enable an optical pickup for scanning an optical disk or a magneto-optical disk to be guided to a target track in a short time and with high accuracy.

[0010]

Means for Solving the Problems The gist of the invention according to claim 1
Move the optical pickup in the radial direction of the disc
Moving mechanism, and a two-input one-output type driving the moving mechanism.
A differential gear mechanism, and the two input shafts of the differential gear mechanism;
Connected pair of feed modes for high-speed movement and low-speed movement
And the transfer required for the optical pickup.
The moving distance is determined by a threshold, and when moving a long distance, the high-speed moving
Only the moving feed motor is driven,
The feed motors for both high-speed movement and low-speed movement are the same.
When moving, and when moving short distances, the feed for low-speed movement
Characterized by having control means for driving only the motor
Optical pickup feeding mechanism. Claim 2
The gist of the invention is that the moving mechanism includes the optical pickup.
Formed on a carriage that supports and guides in the predetermined feed direction
Rack gear, and the differential gear mechanism comprises:
An output gear meshing with the rack gear is provided.
An optical pickup feed mechanism according to claim 1. Contract
The gist of the invention according to claim 3 is that the differential gear mechanism comprises:
Attach to input shaft to which feed motor for high-speed movement is connected
A gear sun gear, a planetary gear meshing with the sun gear,
Connect the input shaft to which the feed motor for low-speed movement is connected.
The input gear attached, the coaxially supported by the sun gear
A planetary gear drive that supports a planetary gear and meshes with the input gear
It has a dynamic gear, internal teeth and external teeth, and the planetary gear meshes with the internal teeth.
Ring teeth with which the external teeth mesh with the moving mechanism
The optical pick-up according to claim 1, further comprising a car.
In the feed mechanism.

[0011]

[0012]

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a plan view showing an embodiment of an optical disk device to which the optical pickup feed mechanism of the present invention is applied, FIG. 2 is a side view of the optical pickup mechanism shown in FIG. 1, and FIG. FIG. 4 is a flowchart for explaining the operation of the system computer shown in FIG. 1.

The optical disk device 101 shown in FIGS.
Except for the feed mechanism of the optical pickup 108, the configuration is substantially the same as that of the conventional optical disc apparatus 1. That is, the optical disk rotation drive system includes a chucking pulley 102 with a built-in yoke 103 for detachably mounting a 106, a turntable 105 with a magnet 104 directly connected to a spindle motor 107, and an optical pickup for rotating and driving the optical disk 106. And a spindle motor 107 disposed inside of the spindle motor 107. Optical pickup 1
08 emits a laser beam, focuses the light on the recording area of the optical disk 106 via the objective lens, focuses the reflected light from the recording area, detects the converged reflected light with a detector, and reads it. The signal is supplied to an external control circuit unit 117 as a signal. The optical pickup 108 is mounted on a rail 10 fixed to a chassis 114.
9 and moves in a direction parallel to the radial direction of the optical disk 106.

The control circuit 117 includes an optical pickup 1
A signal processing circuit 118 that processes an error signal (focus error signal and tracking error signal) from
A spindle motor driving circuit 121 for rotating the spindle motor 107; a feed motor driving circuit 122a that operates at the time of a long-distance track jump; and a feed motor driving circuit that operates at the time of tracing (reproducing) recorded information after the short-distance track jump and the track jump. 122b
Is a system computer 119 for controlling various operations.
It is arranged with. Feed motor drive circuit 12
2a and 122b are feed motors 113a for high-speed movement.
The system computer 119 drives only the feed motor driving circuit 122a when moving a long distance, and drives the feed motor driving circuit 122a when moving a middle distance. Both the motors 122a and 122b are operated at the same time, and at the time of short-distance movement, they function to operate only the feed motor driving circuit 122b, and the differential gear mechanism 100 described later is switched to a different power transmission mode.

The differential gear mechanism 100 includes a sun gear 110 mounted on a shaft of a high-speed moving feed motor 113a.
a, a sun gear 110a and a coaxial ring gear 11
Four planetary gears 111 meshing with the internal teeth of No. 2 and a planetary gear drive gear 123 supported by the chassis 114 coaxially with the sun gear 110a and rotatably supporting the planetary gears 111.
And the input gear 11 attached to the shaft of the low-speed movement feed motor 113b and meshing with the planetary gear drive gear 123.
0b, the sun gear 110a and the input gear 110b
Give an input rotation, and an output rotation is extracted from the ring gear 112. Ring gear 112 which is an output gear
Are meshed with rack gears 108a formed on the side surface of the carriage 108b. The rack gear 10
The rail 8a and the rail 109 constitute a moving mechanism for moving the carriage 108b in a direction parallel to the radial direction of the optical disk 106.

Next, the operation of the optical pickup feed mechanism having the above configuration will be described with reference to FIG. First, as shown in FIGS. 1 and 2, when the optical disk 106 is mounted on the turntable 105 by an optical disk loading / unloading device (not shown), the feed motor drive circuit 122b is stopped by a command from the system computer 119. In this state, the feed motor driving circuit 122a rotates the high-speed moving feed motor 113a to rotate the planetary gear 111 meshing with the sun gear 110a to the ring gear 11a.
Rotational power is transmitted to the rack gear 108a via the second gear 2. Alternatively, while the feed motor driving circuit 122a is stopped, the feed motor driving circuit 122b drives the low-speed moving feed motor 113b to rotate, and from the planetary gear driving gear 123 meshing with the input gear 110b through the planetary gear 111. The rotational power is transmitted to the ring gear 112, and the optical pickup 1 is moved together with the rack gear 108a.
08 moves along the rail 109 toward the innermost circumference of the disk.

When the optical pickup 108 reaches the innermost circumference, the carriage 108b contacts the stopper of the chassis 114, and the optical pickup 108 stops. Here, after a certain time has elapsed, the system computer 119 controls the feed motor drive circuit 122a or the feed motor drive circuit 122b, and the feed motor 11 for high-speed movement.
The supply of the voltage applied to 3a or the low-speed moving feed motor 113b is stopped. At the same time, a laser beam is emitted from the optical pickup 108, a focus search is performed by operating a focus search, and the laser is mounted on a turntable 105 with a built-in magnet 104 directly connected to a spindle motor 107 by a chucking pulley 102 with a built-in yoke 103. Optical disc 106
It is rotated by a spindle motor 107.

When the optical disk 106 starts to rotate,
While applying the tracking servo, the feed motor driving circuit 122a is stopped and the feed motor 113b is stopped.
Optical disk 106 on which a spiral recording area is formed while driving the optical pickup 108 little by little.
Trace information signal. At this time, the system computer 119 operates the spindle motor driving circuit 121 so that a constant linear velocity can be obtained.
Is controlled, and as shown in step (101) of FIG. 4, the TOC (Table Of Content) recorded in the innermost lead-in area of the optical disc 106 is controlled.
An information signal called s) that summarizes the contents of a record is read. When the reading of the TOC is completed, the optical pickup 108 is moved to the position of the start address of the program area by the above-described control and stands by at that position.

Next, when a reproduction command is input by a command input from an external computer or the like, in a step (103) following the judging step (102), the number of tracks up to a head address at which reproduction is started is calculated. Further, in the subsequent judgment step (104), the number of tracks up to the start address at which reproduction is started is determined by a threshold value. If the number of tracks exceeds 300, high-speed long-distance movement is instructed. If the number of tracks is less than the number of tracks, a middle distance medium speed movement is instructed. If the number of tracks is 100 or less, a short distance low speed movement is instructed. More specifically, as shown in steps (105), (106), and (107), the feed motors 113a, 113a and 11
3b is driven alone or simultaneously.

First, in the long distance track jump operation,
Turntable 1 with focus servo operating
The spindle servo 107 is decelerated or accelerated so that the optical disc 106 mounted on the disc 05 by the chucking pulley 102 is rotated at the reproduction start address, and the tracking servo is released. System computer 1
19 drives the high-speed moving feed motor 113a via the feed motor drive circuit 122a while keeping the feed motor drive circuit 122b at rest,
From the planetary gear 111 meshing with 10a to the ring gear 112
The rotational power is transmitted to the rack gear 108 a via the, and the optical pickup 108 is moved along the rail 109 toward the reproduction start address. In this case, the tracking error signal obtained by releasing the tracking servo is processed by the system computer 119, and the feed motor drive circuit 122a is controlled while counting until the number of tracks reaches the number of tracks up to the start address at which reproduction is started. The high-speed movement feed motor 113a is stopped at the position. Simultaneously with the stop of the movement of the optical pickup 108, the tracking servo is operated to trace the information signal of the optical disk 106 in which the spiral recording area is formed, and the subcode is read. As shown in step (115). Next, it is checked whether or not the playback start address is reached, that is, whether or not the target track position has been reached.
As a result, if it is determined that the target track has not been reached, the process returns to step (103) and the necessary track jump is retried.

In the middle distance track jump operation,
While the focus servo is operated, the turntable 105 with the built-in magnet 104 directly connected to the spindle motor 107 and the optical disk 106 mounted by the chucking pulley 102 with the built-in yoke 103 are rotated so that the number of rotations becomes the reproduction start address. While decelerating or accelerating the motor 107, the tracking servo is released, the feed motor driving circuits 122a and 122b are simultaneously operated, and the high speed moving feed motor 113a and the low speed moving motor 113b are simultaneously rotated. Therefore, the rotational power of the high-speed moving feed motor 113a is transmitted from the planetary gear 111 meshing with the sun gear 110a to the rack gear 108a via the ring gear 112, and the rotational power of the low-speed moving feed motor 113b is The power is transmitted from the planetary gear drive gear 123 meshing with the input gear 110b to the rack gear 108a via the planetary gear 111 and the ring gear 112. In this case, since the differential gear mechanism 100 performs a differential operation, the rotation of the sun gear 110a via the planetary gear 111 is superimposed on the rotation of the ring gear 112, and the rack gear 108a moves at an intermediate speed between high speed and low speed. . Thus, the optical pickup 108
Moves along the rail 109 toward the reproduction start address at a medium speed. The system computer 119 processes a tracking error signal obtained by releasing the tracking servo, and calculates the number of tracks up to the start address at which reproduction starts. The feed motor drive circuits 122a and 122b are controlled while counting until they match. At the target track position, the high-speed moving feed motor 113a and the low-speed moving feed motor 113b are stopped, and at the same time as the movement of the optical pickup 108 is stopped, the tracking servo is operated to form the spiral recording area of the optical disk 106. The information signal is traced, the subcode is read, and as shown in step (116), it is checked whether or not the playback start address is reached, that is, whether or not the target track position has been reached. If it is determined that the target track has not been reached, step (103)
Return to and retry the required track jump.

On the other hand, in the short-distance track jump operation, the optical disc 1 is kept operating while the focus servo is operated.
The spindle motor 107 is decelerated or accelerated, the tracking servo is released, and the feed motor drive circuit 122 is turned on so that the rotation number of 06 becomes the rotation number of the reproduction start address.
a, the feed motor drive circuit 122
b drives the low-speed moving feed motor 113b to rotate. Thereby, the low-speed moving feed motor 113b
The planetary gear 111 and the ring gear 11 from the planetary gear drive gear 123 meshing with the input gear 110b attached to the
2, rotational power is transmitted to the rack gear 108a,
The optical pickup 108 moves along the rail 109 toward the reproduction start address. In this case, the tracking error signal obtained by releasing the tracking servo is processed by the system computer 119, and the feed motor drive circuit 122b is controlled while counting until the number of tracks reaches the number of tracks up to the start address at which reproduction is started. The feed motor 113b for low-speed movement is stopped at the position. At the same time as the stop of the optical pickup 108, the tracking servo is operated to trace the information signal of the optical disk 106 on which the spiral recording area is formed, read the subcode, and start the reproduction at the start address as shown in step (117). , That is, whether the target track position has been reached. As a result, if it is determined that the target track has not been reached, the process returns to step (103) and the necessary track jump is retried.

When it is determined that a jump has been made to the head address at which reproduction is started, as shown in the final step (120), spiral recording is performed while controlling the spindle motor 107 by the spindle motor driving circuit 121 at the constant linear speed. The information signal of the optical disk 106 in which the area is formed is traced by the optical pickup 108, and the information signal is reproduced. Note that there are various cases of a track jump required after playback, but the system computer 119
If the number of tracks to the start address to start reproduction again exceeds 300 tracks, a long distance track jump command is output. If the number of tracks to the start address to start reproduction again is 100 or more and less than 300 tracks,
A medium-distance track jump command is output, and if the number of tracks up to the start address to start reproduction is less than 100 tracks, a short-distance track jump command is output. Such a track jump and reproduction operation are repeatedly performed according to an external computer command.

As described above, the above-described optical pickup feeding mechanism is provided with the high-speed moving feed motor 113 when moving a long distance.
, and the differential gear mechanism 100 is transmitted as power to the rack gear 108a as a small reduction ratio transmission means, so that movement to a distant truck can be completed at high speed. By driving the motor 113b, the differential gear mechanism 100 is transmitted to the rack gear 108a as a large reduction ratio transmission means, and can move to a nearby track at an appropriate speed. Eliminate inconveniences such as the occurrence of a track that cannot be stopped after a track jump due to the bias of the stop position due to cogging of the feed motor in the track jump, and the inability to perform high-speed access due to repeated track jumps to the target track. For long-distance and short-distance movements Te, the feed motor 113a of the high-speed movement and low-speed movement, by driving 113b can be simultaneously with fast and slow intermediate speed to a short time and accurately move to the track in the medium distance.

The moving mechanism is an optical pickup 108
108 that supports and guides in a predetermined feed direction
b, and the differential gear mechanism 100 includes the ring gear 112 as an output gear that meshes with the rack gear 108a. Therefore, the reduction ratio of the two-input one-output differential gear mechanism 100 is reduced. Utilizing the fact that it differs according to the combination of inputs, the rotational speed of the ring gear 112 is varied according to the moving distance required for the optical pickup 108, and the rack gear 1 meshed with the ring gear 112 is used.
The feed speed of 08a is switched among three stages of high speed, medium speed and low speed, so that the optical pickup 108 can be fed in a short time and with high accuracy.

Further, the feed motor 113 for high-speed movement
By transmitting the rotational power of a from the sun gear 110a to the ring gear 112 via the planetary gear 111, and from the ring gear 112 to the rack gear 108a of the optical pickup 108, the optical pickup 108 can be moved at a high speed. Also, by transmitting the rotational power of the low-speed moving feed motor 113b to the ring gear 112 and transmitting it from the ring gear 112 to the rack gear 108a, the optical pickup 108 can be moved at a low speed. Feed motor for movement 1
13b, the rotation of the sun gear 110a via the planetary gear 111 is superimposed on the rotation of the ring gear 112, so that the ring gear 112 can be rotated at an intermediate speed between high speed and low speed. Further, the high-speed moving feed motor 113a is disposed substantially at the center of the differential gear mechanism 100, and the low-speed moving feed motor 113a is provided.
b can be arranged in the periphery of the differential gear mechanism 100, so that the arrangement positions of the two feed motors 113a and 113b do not interfere with each other. And the whole mechanism can be made compact.

Further, the moving distance required for the optical pickup 108 is determined by a threshold value.
Only the high-speed movement feed motor 113a is driven, and both the high-speed movement and low-speed movement feed motors 113a and 113b are simultaneously driven during medium-distance movement, and only the low-speed movement feed motor 113b is driven during short-distance movement. Since the system computer 119 is provided, the number of tracks to be jumped when a track jump is requested is determined by a threshold value, and the feed motor 113a for high-speed movement or the low-speed movement is determined according to the long-distance movement, short-distance movement, and medium-distance movement. By selecting the single drive of the feed motor 113b or the simultaneous drive of both feed motors 113a and 113b, the access mode to the target track can be strictly switched and selected. Therefore, for example, instead of simply moving a long distance at a constant high speed, the speed gradually decreases from a high speed to a medium speed and further to a low speed as approaching the target track, so that both short-time movement and movement accuracy can be achieved. It is possible.

In the above embodiment, the number of tracks used for discriminating the threshold values of the high-speed long-distance movement, the medium-speed medium-distance movement and the low-speed short-distance movement is set to 300 tracks and 100 tracks. However, these thresholds can be changed to other values according to the device configuration of the optical disk device.

[0030]

As described above, according to the optical pickup feed mechanism of the present invention, the moving mechanism for moving the optical pickup, the two-input one-output differential gear mechanism for driving the moving mechanism, and the differential gear mechanism Since a pair of feed motors for high-speed movement and low-speed movement connected to the two input shafts of the dynamic gear mechanism are provided, the high-speed movement feed motor is driven during long-distance movement, and the differential gear mechanism is operated. Power is transmitted to the moving mechanism as a small reduction ratio transmission means, and the movement to a distant track can be completed at high speed. On the other hand, when moving short distance, the low speed movement feed motor is driven, and the differential gear mechanism is greatly reduced. By transmitting power to the moving mechanism as a specific transmission means, it is possible to move to a nearby track at an appropriate speed, thereby, for example, in a precise track jump of about 100 tracks or less, It is possible to eliminate inconveniences such as the occurrence of a track that cannot be stopped after a track jump due to the deviation of the stop position due to the cogging of the lead motor, and the inability to perform high-speed access as a result of repeated track jumps to the target track. For medium-distance movement and short-distance movement, the feed motors for high-speed movement and low-speed movement are simultaneously driven, so that a medium-speed track at an intermediate speed between high-speed and low-speed can be reached in a short time. In addition, excellent effects such as accurate movement can be achieved.

Further, according to the present invention, the moving mechanism includes a rack gear formed on a carriage that supports the optical pickup and guides the optical pickup in a predetermined feed direction, and the differential gear mechanism meshes with the rack gear. The output gear is mounted on the output shaft, and the output gear meshes with the rack gear. Therefore, the reduction ratio of the two-input / one-output differential gear mechanism differs depending on the combination of inputs. By using this, the rotation speed of the output gear is varied according to the moving distance required for the optical pickup, and the feed speed of the rack gear meshing with the output gear is switched between three stages of high speed, medium speed and low speed, and In addition, there is an effect that the optical pickup can be transported with high accuracy.

The present invention further provides a differential gear mechanism comprising: a sun gear mounted on an input shaft to which the high-speed moving feed motor is connected; a planetary gear meshing with the sun gear; An input gear attached to an input shaft connected thereto, a planetary gear drive gear that is coaxially supported by the sun gear and rotatably supports the planetary gear, meshes with the input gear, and has internal teeth and external teeth, Since the planetary gear meshes with the internal gear and the external gear meshes with the ring gear with the external gear, the rotation power of the high-speed moving feed motor is transmitted from the sun gear to the ring gear via the planetary gear, By transmitting the optical pickup from the gear to the moving mechanism of the optical pickup, the optical pickup can be moved at a high speed. By transmitting the light from the gears to the moving mechanism, the optical pickup can be moved at a low speed, and when the high-speed moving feed motor and the low-speed moving feed motor are driven simultaneously, the rotation of the ring gear causes the sun via the planetary gear to rotate. Since the rotation of the gears is superimposed, the ring gear can be rotated at an intermediate speed between high speed and low speed, and a high speed moving feed motor is arranged almost at the center of the differential gear mechanism, Since the feed motors can be arranged at the periphery of the differential gear mechanism, the positions of the two feed motors do not interfere with each other. This has the effect that the entire mechanism can be made compact.

Further, according to the present invention, the moving distance required for the optical pickup is discriminated as a threshold value, and only the high-speed moving feed motor is driven during a long-distance movement, and the high-speed moving motor is driven during a medium-distance movement. A control means for simultaneously driving both feed motors for low-speed movement and driving only the low-speed movement feed motor during short-distance movement is provided. Access to the target track by discriminating and selecting single drive of the high-speed feed motor or low-speed feed motor or simultaneous drive of both feed motors according to the long-distance, short-distance and middle-distance movements Aspects can be strictly switched and selected, so that, for example, a long-distance movement instead of simply moving at a constant high speed, Medium speed from the high speed toward the target track, further gradually blunted speed to low speed, an effect equal it is possible to achieve both short move movement accuracy.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of an optical disk device to which an optical pickup feed mechanism of the present invention is applied.

FIG. 2 is a side view of the optical pickup mechanism shown in FIG.

FIG. 3 is an enlarged sectional view of a main part of the optical pickup mechanism shown in FIG.

FIG. 4 is a flowchart for explaining the operation of the system computer shown in FIG. 1;

FIG. 5 is a plan view showing an example of a conventional optical pickup feed mechanism.

FIG. 6 is a side view of the optical pickup mechanism shown in FIG.

FIG. 7 is an enlarged sectional view of a main part of the optical pickup mechanism shown in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 differential gear mechanism 101 optical disk device 102 chucking pulley 103 yoke 104 chucking magnet 105 turntable 106 optical disk 107 spindle motor 108 optical pickup 108a rack gear 108b carriage 109 rail 110a sun gear 110b input gear 111 planetary gear 112 ring gear 113a high speed Movement feed motor 113b Low-speed movement feed motor 114 Chassis 115 Insulator 116 Frame 117 Control circuit section 118 Signal processing circuit 119 System computer 120 Focus tracking drive circuit 121 Spindle motor drive circuit 122 Feed motor drive circuit 123 Planetary gear drive gear

Claims (3)

(57) [Claims] 1. A moving mechanism for moving an optical pickup in a radial direction of a disk, a two-input one-output differential gear mechanism for driving the moving mechanism, and connected to the two input shafts of the differential gear mechanism. Equipped with a pair of feed motors for high-speed movement and low-speed movement, and furthermore, determines a movement distance required for the optical pickup by a threshold value.
However, when moving a long distance, the feed motor for high-speed movement is used.
When moving at medium distances,
Drive both feed motors at the same time
When moving, only the low-speed moving feed motor is driven.
An optical pickup feed mechanism comprising control means . 2. The moving mechanism includes a rack gear formed on a carriage that supports the optical pickup and guides the optical pickup in a predetermined feed direction. The differential gear mechanism includes an output gear that meshes with the rack gear. The optical pickup feed mechanism according to claim 1, further comprising: 3. The differential gear mechanism is connected to a sun gear attached to an input shaft to which the high-speed moving feed motor is connected, a planetary gear meshing with the sun gear, and the low-speed moving feed motor. An input gear attached to the input shaft, a planetary gear drive gear that is coaxially supported by the sun gear and rotatably supports the planetary gear, meshes with the input gear, and has internal and external teeth. 2. The optical pickup feed mechanism according to claim 1, further comprising: a ring gear with which said planetary gear meshes and whose external teeth mesh with said moving mechanism.