JPH10275432A - Disk drive device - Google Patents

Abstract

(57) [Summary] [Problem] To improve and speed up the stability of seek operation. SOLUTION: In the disk drive device, when the frequency of the traverse signal detected by the frequency detecting means at the completion of the movement by the coarse seek becomes equal to or lower than a predetermined frequency (F
In 104), a tracking-on operation (F105) is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive (recording device or reproducing device) corresponding to a disk-shaped recording medium such as an optical disk and a magneto-optical disk.

[0002]

2. Description of the Related Art A disk drive device has a biaxial mechanism for driving an objective lens of an optical head by a tracking error signal obtained from track guide information such as a pit row or a groove in order to control a tracking state of a light spot. Further, a slide mechanism (generally called a sled mechanism) for displacing the relative position between the entire optical head and the disk surface in the disk radial direction is provided.

The seek operation for moving the optical head to a target position (target address) on the disk includes a coarse seek in which the optical head is largely moved to the vicinity of the target position mainly by a thread mechanism, and a read operation after the coarse seek. Based on the address information, the objective lens is moved (track jump) mainly by the two-axis mechanism (the sled may be moved if necessary), and the beam spot position from the optical head reaches the target address. A dense seek is performed. At the time of coarse seek, the tracking servo loop is turned off and the optical head is forcibly moved by the sled mechanism, but at this time, since the beam spot crosses the track on the disk, as a tracking error signal, FIG.
The traverse signal STR as shown in FIG.

When the traverse signal STR is counted,
Since the value is the value of the number of traversing tracks, a coarse seek method controls the sled movement amount by counting the traverse signal waveform, for example.
For example, if the target address is 100 tracks away from the current position, the coarse seek is terminated when the traverse count value reaches 100 after the start of the thread movement. Thereafter, if necessary, fine adjustment movement to the track of the target address is performed by fine seek by track jump.

On the other hand, without performing such a traverse count, the sled movement amount is detected by using an external sensor such as a position sensor or a speed sensor, and when the required movement amount is moved to the target address, the rough movement is performed. Another method is to end the seek. That is, when the external sensor detects that the optical head has reached the vicinity of the target address, the coarse seek is terminated, and then fine adjustment movement to the track of the target address is performed by fine seek by track jump.

[0006]

By the way, in the case of such a seek operation in which the traverse count is not performed, the frequency of the traverse signal STR is not monitored when the tracking servo loop is turned on when the thread movement is completed. . In other words, the seek control system does not know what the frequency of the traverse signal is at the timing of performing the tracking-on.

In the case of a disk with large eccentricity, the frequency of the traverse signal may become extremely high temporarily,
In addition, the frequency of the traverse signal may become extremely high temporarily depending on the behavior of the lens when the objective lens in the biaxial mechanism returns to the mechanical center position at the end of the sled movement.

The servo band of the tracking servo system is generally about several kHz (1 kHz to 3 kHz).
If the frequency of the traverse signal is, for example, several tens of kHz or more, the tracking servo cannot be normally turned on as it is. Therefore, conventionally, the tracking servo is turned on after performing a brake circuit process (masking a tracking traverse signal at a certain timing) to lower the frequency of the traverse signal.

The traverse frequency of the tracking in which the brake circuit process normally operates is assumed to be fx. It is assumed that the frequency of the tracking traverse signal fluctuates as shown in FIG. 5 due to the influence of eccentricity or the like. As shown in FIG. 5C, when the timing at which the tracking servo should be turned on (the timing at which the movement by the coarse seek ends) is TMton2, the traverse frequency fTR is lower than the frequency fx. Operates normally, and the tracking servo can be turned on normally.

However, when the timing at which the tracking servo should be turned on reaches TMton1 as shown in FIG. 5B, the frequency fTR is higher than the frequency fx, so that the conventional brake circuit process can operate normally. In some cases, tracking servo-on may fail. If the tracking servo fails to turn on, it is not possible to shift to the fine seek, the processing until finally reaching the target address is delayed, and the seek operation takes much time.

[0011]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to normally execute tracking-on at the end of a coarse seek and to eliminate a delay in a seek operation.

Therefore, in the disk drive device, the frequency of the tracking traverse signal detected by the frequency detecting means for detecting the frequency of the tracking traverse signal at the time of the coarse seek, Seek operation control means for executing a tracking-on operation when the frequency becomes equal to or lower than a predetermined frequency. The coarse seek is a seek operation in which seek operation control by traverse count is not performed. That is, the present invention observes the frequency of the traverse signal when performing the tracking servo-on after the coarse seek, and performs the tracking-on operation at the timing when the brake circuit processing operates normally and the tracking servo-on becomes a frequency that can be normally executed. Let it run.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a disk drive according to an embodiment of the present invention will be described. FIG. 1 shows a schematic configuration of a reproducing system and a servo system of a disk drive device.

In FIG. 1, a disk 1 is, for example, a CD-ROM disk which is an optical disk of a CD system, and is rotated by a spindle motor 2 during reproduction. Information recorded on the disc 1 is read by the optical head 3. In the optical head 3, for example, a light beam output from a semiconductor laser 3b is passed through an optical system 3c including a diffraction grating, a beam splitter, and the like, through an objective lens 3a.
To the recording surface of the disk 1 as a beam spot. Then, the reflected light is introduced into the detector 3d by the optical system 3b to obtain information used for data reproduction and servo operation.

The objective lens 3a is supported by a biaxial mechanism 4. The biaxial mechanism 4 includes an objective lens 3a for performing focus control and tracking control of the beam spot.
Can be displaced in the direction of contacting and separating from the disk 1 and in the disk radial direction. The entire optical head 3 is configured to be slid in the radial direction of the disk 1 by a sled mechanism 4. The thread mechanism 4 slidably supports the optical head 3 by a rack / pinion gear mechanism, a lead screw mechanism, or the like. When the sled motor inside the sled mechanism is driven, the driving force is transmitted to the gear system, and the operation of moving the optical head 3 is performed. Alternatively, as the thread mechanism 4, a linear motor mechanism for moving the optical head 3 may be employed.

In the optical head 3, the information detected by the detector 3d and output as a current signal corresponding to the light amount is R
Processing such as current-voltage conversion, calculation, and amplification is performed in the F amplifier 5, and a tracking error signal, a focus error signal, and the like are extracted along with the reproduction information of the main data.

An RF signal as reproduction information is supplied to a data decoder 6 and subjected to binarization, EFM decoding, CIRC error correction processing, CD-ROM decoding, and the like, to be reproduction data.
For example, it is output to the host computer. Further, a subcode decoding process is also performed, and information such as an address recorded on the disk 1 as a subcode is extracted. These subcode information are supplied to the system control unit 8.
In the data decoder 6, the EF obtained by the binarization processing is used.
By the pulse generated by injecting the M signal into the PLL circuit,
A reproduction clock for demodulation processing and rotation speed information of the spindle motor 2 are generated. The rotation speed information of the spindle motor 2 is compared with the reference speed information to generate a spindle error signal, which is supplied to the servo circuit 7. The servo circuit 7 controls the operation of the spindle driver 11 based on the spindle error signal, and causes the spindle motor 2 to execute, for example, a CLV (constant linear velocity) spindle rotation.

The tracking error signal TE and the focus error signal FE output from the RF amplifier 5 are supplied to a servo circuit 7. Then, after processing such as phase compensation is performed, the signals are supplied to a two-axis driver 10 that drives the two-axis mechanism 4 as a tracking control signal and a focus control signal. The drive signal output from the biaxial driver 10 is a tracking coil of the biaxial mechanism 4 in the optical head 3,
The voltage is applied to the focus coil, and the movement of the objective lens 3a is controlled in the tracking direction and the focus direction, respectively, in the direction in which the error signal becomes zero.

Further, in the servo controller 8,
A low-frequency component of the tracking error signal TE is extracted and is set as a thread error signal. Then, the thread position control CSLp is generated based on the thread error signal, and the thread driver 9 outputs the thread drive signal SLD. This sled drive signal SLD is applied to a sled motor in the sled mechanism 4, and a sled moving operation is performed. In order to detect the position of the sled mechanism 4, a position / speed sensor 12 formed using an optical sensor, a Hall element, or the like is provided, and an output of the sensor 12 is supplied to the system control unit 8.

A system control section 8 formed by a microcomputer outputs an operation control signal to each section. For example, the servo circuit 7 performs loop opening / closing control of each servo system, application control of a spindle acceleration pulse / deceleration pulse, and the like, control of sled movement for coarse seek operation, and track jump for fine seek. By controlling the laser output of the optical head 3 together with these controls, the entire reproduction operation is controlled. The system control unit 8 communicates with the host computer via the interface unit 13. That is, the system control section 8 executes access (seek) and data read operation of a necessary area of the disk 1 based on a reproduction request from the host computer, and transmits decoded data from the interface section to the host computer. .

The system control section 8 is connected so that a tracking error signal TE from the RF amplifier 5 is supplied. The frequency of the tracking error signal TE can be determined by the frequency counting function 8a in the system control unit 8.

FIG. 2 shows blocks relating to tracking and thread control in the servo circuit 7. The tracking error signal TE from the RF amplifier 5 is supplied to a tracking drive signal generator 7a in the servo circuit 7. In the tracking drive signal generation unit 7a, for example, a phase compensation process, P
A WM modulation process, a low-pass filter process, and the like are performed to generate a tracking drive signal for tracking servo, and the two-axis driver 10 is connected via the TS terminal of the switch 7f.
To the tracking driver 10a.

The tracking driver 10a applies a current to the tracking coil of the biaxial mechanism 4 according to the supplied tracking drive signal, and drives the objective lens 3a. That is, when the switch 7f is connected to the TS terminal, the tracking servo loop is turned on, and the laser spot from the optical head 3 is controlled to follow the track on the disk 1. The switch 7f and a switch 7g described later are connected to the system control unit 8
The switching is controlled by the control signal SS from the controller.

On the other hand, when executing a track jump, the switch 7f is connected to the TJ terminal by the system control unit 8, the tracking servo loop is turned off, and the jump control signal S from the system control unit 8 is output.
TJ is supplied to the jump signal generator 7b. The jump signal generator 7b generates a drive signal for executing a track jump according to the jump control signal STJ,
Tracking driver 10 through the TJ end of switch 7f
a. The tracking driver 10a applies a current to the tracking coil of the biaxial mechanism 4 according to the supplied track jump drive signal, and
To realize a track jump.

As for the sled operation, a low-pass component of the tracking error signal TE from the RF amplifier 5 is extracted by a low-pass filter 7e in the servo circuit 7 to form a sled error signal SLE. The signal is supplied to the signal generator 7c. In the thread drive signal generation unit 7c, for example, phase compensation processing, PWM
A thread drive signal for thread servo is generated by performing modulation processing, low-pass filter processing, and the like, and is supplied to the thread driver 9 via the TS terminal of the switch 7g.

The sled driver 9 applies power to the sled motor in the sled mechanism 4 according to the supplied sled drive signal to move the optical head 3. That is, the state in which the switch 7g is connected to the TS terminal is the state in which the thread servo loop is turned on, and every time the laser spot reaches a state in which the laser spot cannot follow the track of the disk 1 in tracking control of the objective lens 3a. Then, a sled movement is performed, so that the track of the beam spot can be tracked from the inner circumference to the outer circumference of the disk.

On the other hand, when the thread is moved at the time of seeking or the like, the switch 7g is connected to the TM terminal by the system control unit 8, the thread servo loop is turned off, and the move control signal from the system control unit 8 is output. The SSM is supplied to the move signal generator 7d. The move signal generator 7d generates a drive signal for executing a thread movement in accordance with the move control signal SSM, and supplies the drive signal to the thread driver 9 via the TM end of the switch 7g. The sled driver 9 applies power to the sled drive signal motor in accordance with the supplied sled move drive signal, and realizes movement of the optical head 3 at the time of coarse seek or the like.

For example, in the disk drive apparatus of the present embodiment having the above-described configuration, the seek operation detects the sled movement amount using the position / speed sensor 12 and moves the necessary movement amount to the target address. The coarse seek is terminated when it is determined that the search has been performed. Then, at that time, the tracking servo is once turned on, and the address is read in a data readable state. Then, the difference from the target address is detected (although the coarse seek may be performed again if necessary),
By performing track jumps (dense seek) by the number of detected required tracks, the seek to the target address is completed.

Here, in this example, the movement by the coarse seek is completed, and the tracking servo is turned on (that is, the switch 7f,
7g is switched to the TS terminal).
However, by performing the processing shown in FIG. 3, the tracking servo pull-in is favorably realized. Step F101 in FIG. 3 shows the coarse seek execution control. That is, the system control unit 8 sets the switch 7f to T by the switch control signal SS.
By connecting the J terminal and the switch 7g to the TM terminal to turn off each servo loop, the thread move control signal S
This is a state in which a move drive signal is generated in the move signal generation unit 7b by the SM to execute the coarse seek.

Here, when it is determined from the output of the sensor 12 that the thread movement has reached the vicinity of the target address, the process proceeds from step F102 to F103, and first, the move drive of the move signal generator 7b based on the move control signal SSM Terminates signal generation. That is, the thread movement ends. Then, in step F104, it is determined whether or not the frequency fTR of the traverse signal obtained by the frequency counting function 8a is lower than the set “certain frequency fx”. This "certain frequency fx" is a frequency determined by the performance of the optical head 3, the servo band, and the like. That is, the "certain frequency fx" is set as a value of a frequency at which the brake circuit processing operates normally and the tracking servo-on can be normally performed. Is what it is.

If the frequency fTR of the traverse signal is higher than the frequency fx in step F104, the process waits for the processing to proceed, and the time when it is determined that the frequency fTR of the traverse signal is lower than the frequency fx Then, the process proceeds to step F105 for the first time to execute the brake circuit process, and then performs tracking-on control in step F106. That is, the switches 7f and 7g are set to T
Connect to S terminal to turn on each servo loop. At the timing of proceeding to step F105 and subsequent steps, since the frequency of the traverse signal is a frequency at which the brake circuit process operates normally, the tracking servo can be normally turned on.
As a result, the subsequent processing (address discrimination and fine seek) is not delayed by tracking-on failure or the like.

The operation of the control shown in FIG. 3 will be described with reference to FIG. At the time of the coarse seek, the tracking servo loop is turned off. Accordingly, the traverse waveform corresponding to the beam spot crossing the track is obtained as the tracking error signal TE with the sled move. The example of the traverse signal waveform STR before and after completion | finish is shown. At this timing, the frequency of the traverse signal waveform periodically rises and falls due to the influence of the disk eccentricity. In some cases, the frequency may be very high due to the influence of the behavior of the objective lens, and the high frequency returns to the low frequency within a short period of time.

Here, as shown in FIG. 4C, the timing TMton2 at which the tracking servo should be turned on (the timing at which the movement by the coarse seek is completed and the process proceeds to step F104) is lower than the frequency fTR of the traverse signal. If it is time point t0, the process immediately proceeds to step F105, performs a brake circuit process, and then performs tracking servo-on in step F106. Of course, in this case, since the brake circuit process operates normally, tracking-on can be executed without any problem.

On the other hand, as shown in FIG. 4B, the timing TMton1 at which the tracking servo should be turned on is the time t1 when the frequency fTR of the traverse signal is higher than the frequency fx.
In step F104, the process is on standby. In this case, the frequency fT of the traverse signal
The process waits until time t2 when R becomes lower than the frequency fx. At time t2, the brake circuit process in step F105 is performed, and the tracking servo-on process is performed in step F106. That is, at this time, the frequency of the traverse signal is a frequency at which the brake circuit process operates normally, so that tracking-on can be executed without any problem. In particular, since the processing is not performed when the frequency fTR of the traverse signal is high, the processing is not disturbed by, for example, the influence of an extremely high frequency. That is, by the processing of this example, tracking-on after the coarse seek is accurately performed, and a seek operation without delay is realized.

In this embodiment, the sled mechanism for moving the relative position between the optical disc 3 and the optical head 3 in the radial direction of the optical disc 3 by moving the optical head 3 has been described.
The optical head is fixed, the disk is mounted on a turntable provided with, for example, a rack gear, and the rotational force of a slide motor is transmitted to the rack gear so that the turntable slides. Although there is a mechanism for moving the position in the disk radial direction, the present invention can be applied to such a slide mechanism.

[0036]

As described above, according to the present invention, the tracking-on operation is executed when the frequency of the traverse signal detected by the frequency detecting means becomes lower than the predetermined frequency when the movement by the coarse seek is completed. Therefore, there is an effect that the brake circuit process operates normally and the tracking-on can be executed normally, whereby the process is delayed due to the tracking-on failure and the seek operation is not delayed. That is, it is possible to improve the access stability and speed up the access.

[Brief description of the drawings]

FIG. 1 is a block diagram of a configuration of a disk drive device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a servo circuit according to the embodiment;

FIG. 3 is a flowchart of processing at the end of a coarse seek according to the embodiment;

FIG. 4 is an explanatory diagram of an operation at the end of a coarse seek according to the embodiment;

FIG. 5 is an explanatory diagram of an operation at the end of a conventional rough seek.

[Explanation of symbols]

1 disc, 3 optical heads, 4 thread mechanism, 7
Servo circuit, 7a tracking drive signal generator,
7b jump signal generator, 7c thread drive signal generator, 7d move signal generator, 7e low-pass filter, 7f, 7g switch, 8 system controller,
8a Frequency counting function, 9 thread driver, 1
0 2-axis driver, 10a tracking driver, 1
2 Position sensor

Claims (2)

[Claims] As a seek operation for a target position on a disk-shaped recording medium, a coarse seek for moving an optical head to a position near a target position, and after completion of the movement by the coarse seek, a tracking-on operation is performed to obtain address information of the disk. A disk drive device for reading and performing a fine seek for moving the optical head to a target position; frequency detecting means for detecting a frequency of a tracking traverse signal at the time of a coarse seek; and detecting the frequency when the movement by the coarse seek is completed. A seek operation control means for executing a tracking-on operation when a frequency of a tracking traverse signal detected by the means becomes equal to or lower than a predetermined frequency. 2. The disk drive device according to claim 1, wherein the coarse seek is a seek operation in which seek operation control based on a tracking traverse count is not performed.