JPH0227528A - System for seeking optical disk device - Google Patents

Abstract

PURPOSE:To reduce a seek time as a whole by starting the setting decision of the eccentricity of a track immediately without setting the periodic damping waiting time of the linear actuator of an optical head after completing the positioning of coarse seek using a linear scale. CONSTITUTION:The initialization of initialization scale deviation 103 is performed on a counter 8 just before starting seek. After that, the movement of the optical head is started by a coarse actuator 3, and a preset value is counted down by the counter 8, and at a time when a remaining pitch 104 arrives at zero, a seek completion signal 110 is outputted, and the positioning of the coarse seek is completed by driving the coarse actuator 3, and simultaneously, a periodic damping and eccentricity setting waiting circuit 13 is started up. The periodic damping and eccentricity setting waiting circuit 13 generates an eccentricity setting completion signal 113 when eccentric speed is lowered and a pulse interval is extended. In such a way, it is possible to shorten the seek time as a whole by eliminating the periodic damping waiting time of the linear actuator, and that of a light spot set after jump.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a seek method for an optical disc storage device, and more particularly to a seek method for an optical disc that positions a recording/reproducing light spot on a target track of an optical disc at high speed.

[Conventional technology]

One of the seek methods for moving a recording/reproducing light spot of an optical disk device to a target recording track is a two-step seek method that is configured by a combination of coarse seek and fine seek. This method first moves the optical head linearly at high speed to the vicinity of the target track using a coarse actuator such as a linear motor, and then repeatedly jumps from track to track using a fine actuator such as a galvanometer mounted on the optical head. In this method, the optical spot is finally positioned on the target track. Note that an optical disk storage device using this two-step seek method is disclosed in, for example, Japanese Patent Application Laid-open No. 1986-
This is shown in Publication No. 83809 and the like.

[Problem to be solved by the invention]

Generally, the 'two-step seek method' uses an external scale such as an optical linear scale fixed to the base as a position detector during coarse seek, and the scale pitch is an integral multiple of the track pitch. Before starting, read the address of the current track, find the number of tracks N to move to the target track, divide this by the linear scale pitch and round it to obtain the coarse seek movement amount M.Next, start coarse seek, and After moving M distances on the scale, it is settled, and then a track following operation is performed, the address of that track is read, and the deviation from the target track is determined.Then, in order to correct the deviation, it is mounted on the optical head. A galvanometer mirror or the like is used to repeat the jump operation (precision scanning) for each track to make the light spot reach the target track.

In addition, during the above seek process, after the rough seek is completed (after the optical head is moved M distances on the linear scale and the optical head is positioned near the target track), the track eccentricity speed (due to the eccentricity of the center hole of the optical disk) , when the optical head relatively oscillates at a speed that changes sinusoidally in the direction across the tracks of the disk for each rotation of the optical disk, this relative speed) is determined to be less than a predetermined value. By using the track eccentric speed stabilization determining means, the track following servo system is turned on and the light spot is positioned to the nearest track after waiting for the track eccentric speed to become sufficiently slow. However, during a coarse seek, the linear actuator supporting the optical head is accelerated and decelerated in a short time, so the radial vibration of the actuator is large when the linear scale is used for positioning. Before the start of eccentricity speed determination, a timer is used to set an unconditional fixed damping waiting time to wait for the actuator to damp. However, this problem has been solved in that the seek time becomes longer by the damping waiting time. had.

Furthermore, due to the linear scale quantization error, rounding error, optical disk eccentricity error, etc. during the coarse seek, the positioning error at the end of the coarse seek becomes large, resulting in a problem that the fine seek time increases. .

Furthermore, during precision seek, each time the jump is repeated, the precision actuator (
damped vibration of the mirror) occurs. Therefore, in the conventional method,
A timer is set up to wait for a certain settling time unconditionally, and the next jump is performed after the timer setting time.
As a result, there is a problem in that the interval between each jump becomes long and the precision seek time becomes long.

In this way, both the damping waiting time when moving from coarse seek to eccentric speed stabilization judgment and the damping waiting time for each jump are set in advance by a timer, so even though the vibration has already been sufficiently damped, the next In some cases, it is not possible to proceed with the abnormal operation at the stage (e.g., eccentric speed stabilization determination), which causes the seek time to become long.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, shorten the attenuation waiting time when transitioning from coarse seek to track eccentric speed stabilization judgment, and the attenuation waiting time for each jump, and thereby reduce the overall An object of the present invention is to provide a seek method for an optical disk device that shortens seek time.

[Means to solve the problem]

As a result of various studies, the inventor of the present invention found that both the vibration damping waiting time set before determining the track eccentric speed settling and the damping waiting time set for each track jump are unnecessary.

Therefore, in order to achieve the above object, the seek method of the optical disk device of the first invention of the present application sets a vibration damping waiting time (timer) of the linear actuator of the optical head after the coarse seek positioning using the linear scale is completed. The configuration is such that the track eccentricity stabilization determination is started immediately without any delay.

Further, the seek method of the optical disk device according to the second invention of the present application is configured such that the jump settling determining means immediately starts the determining operation without setting a light spot settling waiting time (timer) after each jump.

[Effect]

The effect based on the above configuration will be explained.

According to the first and second inventions, it is possible to eliminate the linear actuator vibration damping waiting time that was conventionally set after rough seek positioning and the optical spot vibration damping waiting time that was conventionally set after jumping, so that the overall Seek time can be reduced.

In this case, even if the timers for both damping waiting times are eliminated, there is no risk of proceeding to the next operation before the vibrations of the linear actuator and the light spot are not sufficiently damped. The reason for this is believed to be that the track eccentric speed settling determining means and the jump settling determining means do not generate an output indicating a stable state before these vibrations are sufficiently attenuated.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to the drawings.

First, the embodiment of the first invention will be explained using FIGS. 1 to 4.
This will be explained in comparison with the conventional technology.

FIG. 1 is a diagram showing the seek time structure of a two-step seek method of a general optical disc device.

The overall seek time is roughly divided into four parts, ■
is the coarse seek time during which the optical head moves at high speed using the linear scale as a position detector, ■ is the rough seek settling time until the coarse seek positioning accuracy falls within 1 pitch (64 tracks) of the linear scale, ■ indicates the time from when the track following servo system is activated until track following actually begins, and ■ indicates the precision seek time due to repeated track jumps.

Now, the configuration and operation of the embodiment will be described in detail with reference to the block diagram shown in FIG. In addition, in this example, directly related
Periods from 1 to 2, especially period 2, will be described in detail, and details of the structure and operation of the fine seek in 2 will be explained in the embodiment of the second invention, and the explanation will be omitted here.

First, immediately before the start of seek, the initial setting scale deviation 103, which is obtained by dividing the track deviation between the current track and the target track by the linear scale pitch and rounding the result, is initialized in the counter 8. After that, the coarse actuator 3 starts moving the optical head, and every time the optical head moves by l pitch, the zero cross pulse generation circuit 7 generates a pulse 102, and the counter 8
The remaining pitch to the target point is 104 by counting down the set value by 4 degrees.
The command speed 105 from the speed command table 9 is converted into an analog signal 106 by the D/A converter 10, and the error signal 11 with respect to the detected speed 107 by the speed sensor 2 is output.
6 drives the coarse actuator 3. Then, when the remaining pitch 104 becomes 0 (the boundary between ■ and ■ in FIG. 1), the seek end signal 110 is output, the switch 11 is switched to the opposite side as shown in the figure, and the output signal 10 of the linear scale l is
1, the coarse actuator 3 is driven to complete coarse seek positioning. At the same time, the coarse seek end signal 11
0 activates the vibration damping and eccentricity settling wait circuit 13. A track deviation signal 115 detected by the optical spot detection sensor 5 is input to a zero cross pulse generation circuit 14, and a track cross pulse 116 is generated. The vibration damping and eccentricity settling wait circuit 13 receives the track cross pulse 116 and generates an eccentricity settling end signal 113 when the track eccentricity speed slows down and the pulse interval becomes longer. In other words, as mentioned above, the optical disc swings sinusoidally in the direction across the track due to the eccentricity of the optical disc, so the moment when this swing speed becomes zero (when the pulse interval is the longest). The boundary between ■ and ■ in the figure) is detected, an eccentricity settling completion signal 113 indicating that the eccentricity speed has been stabilized is generated, and the track following servo system is pulled in. Therefore, in response to this eccentricity settling end signal 113, the switch 12 and the switch 15 are switched to the opposite positions from those shown in the figure, and the track following servo circuit 4 drives both the coarse actuator 3 and the fine actuator 6 to move the light spot to the target track. The coarse seek operation is completed by following the track near . After that, jump from track to track and move to the target track.

Next, the vibration damping and eccentric stabilizing circuit 13, which is a feature of this embodiment, will be described in detail. FIG. 3 is an internal configuration diagram of a conventional vibration damping and eccentricity settling wait circuit 13. In the prior art, after the coarse seek end signal 110 is issued, the vibration damping wait timer 17 unconditionally sets T! After waiting l, a timer output signal 117 is generated. The timer output signal 117 activates the track eccentric speed stabilization wait circuit (truck eccentric speed setting determination circuit) 16 to start the determination operation of eccentricity settling (that the eccentric speed has been stabilized). Therefore, even if
Even if the decay is completed within the decay waiting time TD, it is necessary to wait unconditionally for the set time To.

In this way, in the conventional technology, the track following servo system is activated after waiting a certain time T and then after the time for determining the eccentric speed settling has passed, resulting in extra seek time. There is a problem.

In contrast, in this embodiment, as shown in FIG. 4, the vibration damping wait timer 17 is omitted, and the rough seek end signal 1
10 is directly applied to a track eccentric speed settling wait circuit (track eccentric speed settling determination circuit). With this configuration, the track eccentric speed settling wait circuit 16 is activated at the same time as the rough seek end signal 110 is issued, so the extra waiting time such as the above-mentioned To is eliminated, and the seek time can be shortened.

Note that, as described above, even if the timer 17 is abolished, the settling end signal 113 will not be output before the vibrations caused by the coarse actuator are attenuated. That is, the track eccentric speed stabilization wait circuit 16 includes a circuit that detects when the vibration amplitude has become below a predetermined level, and when the vibration amplitude is below the predetermined level, the instantaneous speed becomes zero and an output is generated.

Next, an embodiment of the second invention of the present application will be described with reference to FIGS. 5 to 8.

Although FIG. 5 shows the same general seek time structure as in FIG. 1 again, here we have expanded a part of the fine seek time due to repeated track jumps, which is a feature of this embodiment. Shown. As shown, each jump is usually accompanied by a damped oscillation of the light spot (mirror).

Here, the configuration and operation of this embodiment will be explained in detail with reference to FIG. First, before starting a seek, a value M103 obtained by rounding the deviation N between the current track address and the target track using a linear scale pitch is set in the counter 8, and then a coarse seek operation is performed in which the optical head is moved at high speed by the coarse actuator 3. The counter 8 is subtracted by the signal 102 obtained by converting the output 101 of the linear scale l into a zero-cross pulse by the pulse generating circuit 7. - A speed command value 105 corresponding to the number of remaining scales 104, which is the output of the counter 8, is generated from the speed command table 9 through a rough seek, and this command value 105
The speed control for driving the coarse actuator 3 is performed using the signal 106 converted by the D/A converter 10 and the deviation signal 116 of the speed detection signal 107 of the speed sensor 2. When counter 8 reaches "0", δ switching signal 1 is sent from the counter.
10 switches the switch 11 to perform position control for coarse seek settling using the output signal 101 of the linear scale. At the same time, in order to complete the coarse seek and perform the tracking operation, the coarse actuator vibration damping wait timer → 17 is activated for a certain period of time by the signal 110 to wait for the vibration to decay, and then output after the damping waiting time. The track eccentric speed setting circuit 16 is activated by the signal 117, and the system waits for the eccentric speed of the truck to settle (to reach zero) as follows. That is, as described above, when the optical spot swings sinusoidally across the track every rotation of the optical disk due to the eccentricity of the track, the optical spot position detection sensor 5 detects the track deviation signal 115, and the cross track is detected. The pulse generator circuit 14 generates a pulsed signal 116. This pulse signal 116
When the pulse width exceeds a certain value and it is detected that the track eccentric speed has become slower than a certain value, the detected moment is captured and pulse 113 is output, and switches 12 and 15 are turned on at the same time. The tracking servo system is turned on by switching to the opposite position as shown in the figure, and the coarse actuator 3 and fine actuator 6 are driven by the tracking servo circuit (track following servo circuit) 4 to follow the light spot. The reason why the switching to the tracking servo system is performed at the time when the eccentric speed is minimum in this way is to facilitate the pull-in to the servo system. and,
Here, after reading the address of that track (a track near the target track), the amount of deviation to the target track is calculated, and the tracking servo is temporarily turned off at the time of jump by the jump switching signal 222 from the track jump drive circuit 22. Immediately after, the fine actuator 6 is activated by the jump drive signal 221 from the drive circuit 22 mentioned above.
to perform jumping movements. At this time, as shown in an enlarged view in FIG. 5, each jump operation is accompanied by damped vibration of the light spot (mirror). Therefore, after the jump, the track deviation signal 115 detected by the optical spot position detection sensor 5 is sent to the jump motion stabilization wait determination path 23, and when it is determined that the jump damping vibration has stabilized, the jump Setting end signal 231
Output.

As a result, the next jump drive signal 221 is output from the track jump drive circuit 22, and the next jump operation is performed. Thereafter, a fine seek operation is performed D times including the jump operation in the same manner, and the target track is reached.

Among the configurations and functions described above, the jump operation that is directly related to the present invention will be explained in detail in 1' below. FIG. 7 shows the internal configuration of a conventional jump operation settling wait circuit 23. As shown in the figure, conventionally, after a jump, in order to wait for the optical spot track deviation signal 115 to settle, a settling judgment wait timer 233 first activates the jump switching signal 222.
After unconditionally waiting for a certain period of time T from the time of occurrence, the settling determination circuit 232 starts determining the settling, and when it is determined that the settling has been completed, outputs the settling end signal 231,
Move to the next jump motion. As a result, even if the settling judgment wait timer 233 settles within the waiting time T1, it is necessary to wait T unconditionally, so the time interval between jump operations becomes longer, and as a result, the precision seek time becomes longer. Ta. On the other hand, in this embodiment, as shown in FIG.
2, the determination of settling is started immediately from the time of jump drive, and the settling end signal 2 is sent at the same time as settling ends.
31 and immediately moves to the next jump, the jump interval is shortened, which has the effect of shortening the precision seek time.

Note that, similarly to the first embodiment, the settling judgment wait timer 233
Even if it is abolished, due to the action of the settling judgment circuit 232, the judgment output 231 will not be generated before the vibration of the light spot after the jump has stabilized.

In the above embodiment, the rough actuator vibration damping wait timer 17 or the post-jump settling judgment wait timer 233
However, both timers 17 and 2 are omitted.
33 may be omitted.

〔Effect of the invention〕

As described in detail above, according to the seek method of the optical disk device of the present invention, the timer for waiting for the vibration damping of the coarse actuator during a coarse seek and the timer for waiting for the optical spot settling time after a jump during a fine seek are omitted. So,
This provides excellent effects such as the ability to shorten seek time by eliminating the waiting time required for coarse seek and the waiting time required for fine seek.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the seek time of a two-step seek method of an optical disk device, Fig. 2 is a block diagram for explaining an embodiment of the present invention, and Fig. 3 is a diagram of a conventional vibration damping and eccentricity settling wait circuit. FIG. 4 is a block diagram of a vibration damping and eccentricity settling wait circuit according to an embodiment of the present invention, FIG. 5 is a block diagram of a seek time of a two-step seek method of an optical disk device, and FIG. FIG. 7 is a block diagram of a conventional jump operation settling wait circuit, and FIG. 8 is a block diagram of a jump operation settling wait circuit according to another embodiment of the present invention. 1--Linear scale, 2--Speed sensor, 3--Rough actuator, 4--
- Track following servo circuit, 5 - Optical spot position detection sensor, 6 - Precision actuator (mirror), 7 - Zero cross pulse generation circuit, 8
--- Counter, 9 --- Rough seek speed command table, 13 --- Vibration damping and eccentricity settling wait circuit, 14 --- Zero cross pulse (cross track Pulse) Generation port I, I6・-1−−〜−−
・Truck eccentric speed settling wait circuit, 17・------・
- (coarse actuator) vibration damping wait timer, 22.
・−・・・Track jump drive circuit, 23−・−°・
Jump operation settling wait circuit, 110... - Coarse seek end signal (coarse seek speed control/position control switching signal), 11
3.-----1 eccentricity settling end signal (tracking servo switching signal), 115--1--tracking deviation signal, 116---1 track cross pulse, 117--. ...-Timer output signal, 221--
・−Track jump drive signal, 222・−・・−・・
- Track jump switching signal, 231--Jump operation settling end signal, 2'32--Settling judgment circuit, 233--Settling judgment timer. Fig. 1 Fig. 2 Fig. 3 Fig. 4 and 6 Shafra war old 14 gift box each Fig. 6

Claims (1)

[Scope of Claims] 1. Rough seek means for positioning an optical head near a target track of an optical disk at high speed by a coarse actuator using an external linear scale; and means for determining the settling state of a recording/reproducing light spot of the optical head. , when the determination means determines that the light spot has been settled after positioning by the rough seek means, a track following servo system is activated to once read a track address, and then the light spot is caused to jump from track to track. In the seek method of the optical disc device, the determination means includes a fine seek means for moving to and positioning the target track using
A seek method for an optical disk device, characterized in that the track eccentricity speed settling determination is started immediately after the positioning by the rough seek means. 2. Rough seek means for positioning the optical head near a target track on the optical disk at high speed by a coarse actuator using an external linear scale; and after positioning by the coarse seek means, a fine actuator mounted on the coarse actuator moves the optical head toward In a seek method of an optical disk device, the optical disk device has a precision seek means for moving and positioning a recording/reproduction light spot by jumping track by track to the target track, wherein the precision seek means determines the settling state of the light spot after each jump. a jump driving means for causing the next jump to be performed when the after-jump determining means determines that the light spot has been stabilized; An optical disc device characterized in that it is configured to start determination from.