JPH10261226A - Servo control method for high-speed data accessing of optical disk reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform high-speed accessing by controlling the rotational number of a spindle motor based on proper RPM during a thread movement driven by a feed motor in an optical disk reproducing device. SOLUTION: A system control unit 24 outputs a feed control signal for kicking a thread to a feed motor 22 and simultaneously outputs a spindle control signal for reducing the rotational number per minute of a spindle motor 20 to the same. Then, by retrieving an inputted FGP, the RPM of the spindle motor 20 is detected. Then, a proper RMP corresponding to a target track preset on a table is compared with the detected RPM, a spindle control signal corresponding to its difference is outputted to the spindle motor 20 and thereby control is performed to make rotation based on the proper RMP. Then, the positioning of the thread on the target track is inspected and, if its positioning is determined, the position of the thread is read and data is read from a disk 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo control of an optical disk reproducing apparatus, and more particularly to a servo control method of a feed motor and a spindle motor for high-speed data access.

[0002]

2. Description of the Related Art Generally, data is recorded on an optical disk at a constant linear velocity. That is, the length of the data recorded on the disk traced in a certain time is the same. Therefore, the spindle motor is controlled so as to rotate at a low speed on the outer periphery of the disk, and is controlled at a constant linear speed (CLV) so as to rotate at a higher speed toward the inner periphery. In a conventional optical disc reproducing apparatus, the spindle motor is controlled by using a forced kick or break having a time delay when the spindle motor is a brush motor, or by an event time of a pulse input to a hall sensor when the spindle motor is a brushless motor. It was determined whether the speed of the currently rotating spindle motor was appropriate for reading data. In other words, the thread (s
After controlling the spindle motor so as to have a rotation speed at which data can be read out after moving (led) and positioning it on the target track. That is, in the conventional optical disc reproducing apparatus, after the feed is controlled to move the thread to the target track, the data is read out by controlling the rotation speed of the spindle motor. In this case, the moving speed of the thread described above is calculated as follows. Assuming that the position of the current thread is A and the position of the target track is B, the total movement distance 1 is BA. Therefore, the thread moving speed Vs = 1 / t. At this time, if l is constant, the thread moving speed V
s = (constant) / t. Therefore, the sled moving speed Vs can change the search time for a certain distance.
However, no matter how fast the thread is moved onto the target track, in order to read data from the disk, it is necessary to wait until the rotation speed of the spindle motor is locked. In other words, the earlier the locking time of the spindle motor, the shorter the time for the optical pickup to read data from the disk.

Hereinafter, the search time of the conventional optical disc reproducing apparatus will be described with reference to the timing chart of FIG. 1 for the servo control of the feed motor and the servo control of the spindle motor for moving the above-mentioned thread. FIG. 1 is a timing chart of a feed motor control signal FCS applied to a feed motor of a general optical disc reproducing apparatus.
In the figure, if the current track position of the thread is 675
At address 00 and the target track is address 157485,
The servo signal processing unit controls the feed motor control signal FC so that a thread kick is made at address 67500 of the current track.
After applying S, the thread is finally stopped so that constant speed, deceleration, and acceleration control are sequentially performed. In this case, the time from the "kick" point of the thread to the top of the thread is defined as a thread kick time T1. The servo signal processing unit reads data from the address of the target track 157485 after the final search time T2 for focusing the target track after the thread kick time T1. At this time, during the period of the final search time T2, the rotation speed of the spindle motor is controlled at an appropriate speed of the corresponding track, which is obtained when reading data. As a result, when reading data from the target track, the conventional optical disc reproducing apparatus has a problem that data access is delayed by a thread kick time T1 and a final search time T2.

In the conventional optical disc reproducing apparatus, when the inner and outer tracks specified by the sled are mutually moved,
The sled movement speeds Vs (that is, when the movement distance of the inner and outer tracks is constant at 1) do not coincide with each other. This will be described with reference to FIGS. 3A and 3B.
FIG. 3A shows a case where a thread located on a disc of a conventional optical disc reproducing apparatus is moved to inner and outer tracks.
This shows the number of rotations of the spindle motor which changes non-linearly thereby.

Referring to FIG. 3A, when the thread moved by the feed motor is moved from the inner circumference to the outer circumference (that is, from L1 to L2 or L1 → L3, L1).
→ L4), the length of the tracks L1 to L4 is L2−L1
= L4-L3, the distance that the thread is moved from the inner circumference to the outer circumference is the same as the distance that the thread is moved from the outer circumference to the inner circumference. However, the change in the number of revolutions of the spindle motor depending on the moving distance is AB> CD. Therefore, when the sled is moved from the outer periphery to the inner periphery and from the inner periphery to the outer periphery, there is a problem that a difference in the rotation speed of the spindle motor occurs.

[0006]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a servo control method capable of accessing data at a high speed in an optical disk reproducing apparatus.

[0007]

According to the present invention, there is provided a servo control method for high-speed data access of an optical disk reproducing apparatus for reading data written on the optical disk. When the first command is received, a first feed control signal for kicking the thread with the feed motor is output in response to the first command.
And a second step of outputting a spindle control signal to rotate the spindle motor at a specified RPM corresponding to the target track in response to the command and receiving the command. When the spindle motor rotates at a predetermined RPM, a third step of outputting a spindle control signal for locking the rotation of the spindle motor in response to the third step, and an FGP generated by driving the feed motor are performed. A fourth step of counting and checking whether the thread is located on the target track; and, if the inspection result indicates that the thread is located on the target track, outputting a feed control signal for stopping the thread and then finalizing And performing a search.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, numerous specific details are provided for a more general understanding of the present invention, such as track addresses, spindle motor rotational speeds, and specific process flows. It will be apparent to one of ordinary skill in the art that the present invention may be practiced without these specific details. In addition, a detailed description of known functions and configurations that may obscure the gist of the present invention will be omitted.

FIG. 2 is a schematic block diagram of an optical disk reproducing apparatus according to the present invention. In FIG. 1, a pickup unit 12 optically picks up information recorded on a disk 10 and converts the information into an electric signal, and includes an actuator for focusing and tracking. The RF amplifier 14 amplifies the signal of the pickup 12 and extracts a servo signal for servo and EFM (Eight to Fourteen Modulation) data. The digital signal processing unit 16 converts the EFM data extracted from the RF amplification unit 14 into a TOC (Table of Content).
s) Demodulate the data, generate and output a CLV (constant linear velocity) control signal. The servo signal processing unit 18 includes a servo signal of the RF amplification unit 14 and a CLV of the digital signal processing unit 16.
A control signal is input to generate a servo control signal (spindle control signal, feed control signal) for performing stable servo, and output it to the feed motor 22 and the spindle motor 20, respectively. The spindle motor 20 receives a spindle control signal (hereinafter referred to as “SC”) of the servo signal processing unit 18.
S ”) to perform CLV control on the disk 10. The feed motor 22 moves the pickup unit 12 by a feed control signal (hereinafter, referred to as“ FCS ”) of the servo signal processing unit 18. The system control unit 24 The memory has a table for controlling the spindle motor 20 at an appropriate RPM (revolutions per minute) defined by the thread position, and the FGP input from the signal detection amplifier 26 is provided.
The servo control of the spindle motor 20 is performed in response to (frequency generator pulse). The signal detection / amplification unit 26 generates FGP by rotation of the spindle motor 20 and outputs the generated FGP to the system control unit 24.

FIG. 3B shows the number of revolutions of the spindle motor 20 which is linearly changed when performing the servo control according to the present invention. FIG. 4 shows the system control unit 24 for high-speed data access according to the present invention. FIGS. 5A to 5C are servo control flowcharts according to an embodiment of the present invention, in which a feed control for controlling the feed motor 22 and the spindle motor 20 when the thread is moved from the inner circumference to the outer circumference. FIG. 4 is a timing chart of a signal FCS and a spindle control signal SCS. FIGS. 6A to 6C are timing charts of the feed control signal FCS and the spindle control signal SCS when the thread is moved from the outer circumference to the inner circumference according to the embodiment of the present invention.

The servo control process of the system control unit 24 for moving the thread from the inner track to the outer track will be described below with reference to FIGS. 4 and 5A to 5C. First, the thread is moved to the inner track L1 (0: 2: 15) on the disk (at this time, the rotation speed of the spindle motor 20 is A) and the thread is moved to the target track L2 (20 : 00: 00), the system control unit 24 outputs a feed control signal FCS to the feed motor 22 to control the servo signal processing unit 18 to kick the thread to the feed motor 22 at the same time. After the spindle control signal SCS for breaking the spindle motor 20 is output to the spindle motor 20 (steps 40 and 42), 44
Proceed to stage. In this case, the timing chart of the feed control signal FCS and the spindle control signal SCS applied to the feed motor 22 and the spindle motor 20 is shown in FIG.
(A). That is, the system control unit 2
4 outputs a feed control signal FCS for kicking the thread to the feed motor 22 at time T3, and outputs a spindle control signal SCS for reducing the number of revolutions per minute of the spindle motor 20 to the spindle motor 20 at the same time T3. Output. Thereafter, the system control unit 24 detects the RPM of the spindle motor 20 by searching for the FGP input through the signal detection and amplification unit 26 (step 44).
In this detection method, the RPM of the spindle motor 20 is detected by checking the period and the input period of the FGP input through the signal detection amplification unit 26. FGP as described above
The method of detecting the RPM of the spindle motor 20 by the input of is known. Thereafter, the system controller 24 determines whether the rotation speed of the spindle motor 20 is an appropriate RPM for reading data (step 46). In the discrimination method, the appropriate RPM corresponding to the target track set in advance on the table is compared with the RPM detected in 44 steps, and a spindle control signal SCS corresponding to the difference is output to the spindle motor 20 to output the spindle control signal. Control is performed so that the rotation of the motor 20 is rotated at an appropriate RPM. If the discrimination result at step 46 indicates that the spindle motor 20
Is not the proper RPM, the system control unit 24 returns to step 42 and continuously outputs the spindle control signal SCS for breaking the spindle motor 20. Thereafter, if the spindle motor 20 rotates at an appropriate RPM for reading data from the target track L2, the system controller 24 proceeds to step 48, locks the rotation of the spindle motor 20, and then proceeds to step 50. Here, the locking time is the time T3 'shown in FIG. 5A, and the rotation speed of the spindle motor 20 at this time is B. Thereafter, at step 50, the system control unit 24 checks whether the thread is located at the target track L2. If the thread is located at the target track, the process proceeds to step 52, at which the feed control signal FCS for stopping the thread is stopped.
, And the process proceeds to step 54. In step 54, the system control unit 28 reads the current thread position, performs a final search, and reads data from the disk 10.

Hereinafter, the track L2 (20:00:00)
At the target track L3 (40: 00: 0).
The control process when moving to (0) will be described with reference to FIG. Currently the thread is on track L2 (20:00:
00) (at this time, the rotation speed of the spindle motor 20 is B), the thread is moved to the target track L3 (4
At 0:00:00), the system control unit 24 controls the servo signal processing unit 18 in steps 40 and 42 to send the feed control signal FCS for kicking the thread in the feed motor 22 at steps 40 and 42. And outputs a spindle control signal SCS for breaking the spindle motor 20 to the spindle motor 20, and then proceeds to step 44. In this case, the system control unit 24 outputs a feed control signal FCS for kicking the thread to the feed motor 22 at the time T4, and at the same time T3, the spindle control signal for decreasing the rotation speed per minute of the spindle motor 20. The SCS is output to the spindle motor 20. Thereafter, the system control unit 24
At this stage, the FGP input through the signal detection amplifier 26 is searched to detect the RPM of the spindle motor 20. At step 46, the system control unit 24 determines whether the rotation speed of the spindle motor 20 is a proper RPM for reading data, and if the spindle motor 20 is rotated at a proper RPM, the system control unit 24. 24 proceeds to step 48 to lock the rotation of the spindle motor 20, and then proceeds to step 50. At this time, the locking time and the rotation speed of the spindle motor 20 are T4 'and C, respectively. Thereafter, at step 50, the system control unit 24 checks whether the thread is located at the target track L3. If the thread is located at the target track, the process proceeds to step 52. 5
After outputting the feed control signal FCS for stopping the thread in two stages, the system control unit 24 performs a final search in 54 stages. On the other hand, the track L3 (40:
00:00) to the target track L4 (6
0:00: 00), the control process is performed by the same control procedure as described above. At this time,
Thread "kick" controlled by the system control unit 24
The time point and the "locking" time point of the spindle motor 20 are performed at time points T5 and T5 ', respectively, as shown in FIG. Hereinafter, a servo control process of the system control unit 28 when the thread is moved from the outer track to the inner track will be described with reference to timing charts shown in FIGS. 6 (A) to 6 (C).

First, the thread is moved to the track L1 (00:00) while the current thread position is located at the track L2 (20:00:00) on the disk (at this time, the rotation speed of the spindle motor 20 is B). 00:00), the system control unit 2
4 controls the servo signal processing unit 18 to kick the sled and outputs a feed control signal FCS and a spindle control signal SCS for increasing the number of revolutions per minute of the spindle motor 20 to the feed motor 22 and the spindle motor 20, respectively. . In this case, the timing chart of the feed control signal FCS and the spindle control signal SCS applied to the feed motor 22 and the spindle motor 20 is as shown in FIG. That is, the system control unit 24 outputs the feed control signal FCS for kicking the thread to the feed motor 22 at the time T6, and the spindle control signal SCS for increasing the rotation speed per minute of the spindle motor 20 at the same time T6. Is output to the spindle motor 20. Thereafter, the system control unit 24 searches the FGP input through the signal detection amplification unit 26 to detect the RPM of the spindle motor 20. Then, when the spindle motor 20 rotates at an appropriate RPM for reading data from the target track L1, the system control unit 24 sets the rotation of the spindle motor 20 to "locking" at time T6 '(the rotation of the spindle motor 20 at this time). After the rotation speed A), it is checked whether the thread is positioned on the target track L1. As a result of the inspection, when the thread is located at the target track, the system control unit 24 outputs a feed control signal FCS for stopping the thread, reads the current thread position, and performs a final search.

Hereinafter, track L3 (40:00:00)
At the target track L2 (20: 00: 0).
The control process in the case of moving to (0) will be described with reference to FIG. Currently, the thread is on track L3 (40: 0
0:00) (at this time, the rotation speed of the spindle motor 20 is B) and the thread is moved to the target track L2.
(20:00: 00), when the command to move to (20:00: 00) is received, the system control unit 24 outputs a feed control signal FCS to "kick" the thread to the feed motor 22 at time T7, and the spindle motor 2
A spindle control signal SCS for increasing the number of revolutions per minute of 0 is output to the spindle motor 20. Thereafter, the system control unit 24 searches the FGP input through the signal detection amplification unit 26, detects the RPM of the spindle motor 20, and determines whether the RPM is appropriate for reading data on the target track L2. As a result, if the spindle motor 20 rotates at an appropriate RPM, the system control unit 24 locks the rotation of the spindle motor 20 at time T7 'and then checks whether the thread is positioned on the target track L2. As a result of the inspection, when the thread is located on the target track, the system control unit 24 outputs a feed control signal FCS for stopping the thread, and then performs a final search.

On the other hand, track L4 (60:00:00)
At the target track L3 (40: 00: 0).
The control process for moving to 0) is performed according to the same control procedure as described above. At this time, the thread kick time and the spindle motor 2 controlled by the system controller 24 are controlled.
0 is locked at time T as shown in FIG.
8 and T8 '. As described above, by controlling the RPM of the spindle motor with an appropriate RPM for reading data before the thread is positioned on the target track, the data access time can be reduced.

As described above, the number of rotations of the spindle motor 20, which changes according to the track by performing the servo control process, changes linearly as shown in FIG. That is, when the track L2-L1 is the same as the track L4-L3, the changes AB and C of the rotational speed of the spindle motor 20 are performed.
By controlling the value of -D the same, there is no difference in the rotation speed of the spindle motor 20 for the same moving distance.

[0017]

As described above, according to the present invention, the rotation speed of the spindle motor is adjusted to an appropriate RPM during the movement of the sled by the drive of the feed motor in the optical disk reproducing apparatus.
, Data can be accessed at high speed.

[Brief description of the drawings]

FIG. 1 is a timing chart of a feed motor control signal FCS for controlling a feed motor of a general optical disc reproducing apparatus.

FIG. 2 is a block diagram of an optical disk reproducing apparatus according to the present invention.

FIG. 3A is a change characteristic diagram of a rotation speed of a threaded motor that changes non-linearly according to a conventional technique, and FIG. 3B is a change characteristic diagram of a rotation speed of a threaded motor that changes more linearly according to the present invention; is there.

FIG. 4 is a control flowchart of a system control unit according to the present invention.

FIGS. 5A to 5C are timing diagrams of control signals for controlling the feed motor and the spindle motor when the thread is moved from the inner circumference to the outer circumference according to the embodiment of the present invention.

FIGS. 6A to 6C are timing diagrams of control signals for controlling a feed motor and a spindle motor when a thread is moved from an outer circumference to an inner circumference according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Disc 12 Pickup part 14 RF amplification part 16 Digital signal processing part 18 Servo signal processing part 20 Spindle motor 22 Feed motor 24 System control part 26 Signal detection amplification part

Claims (4)

[Claims] 1. A servo control method for high-speed data access of an optical disk reproducing apparatus, wherein when a command for reading data written on the optical disk is received, a feed motor drives the thread in response to the command. Outputting a feed control signal for kicking the motor; and, when the command is received, outputting a spindle control signal to rotate the spindle motor at a specified RPM corresponding to the target track in response to the command. And a third step of outputting a spindle control signal for locking the rotation of the spindle motor in response to the rotation speed of the spindle motor being searched and the spindle motor rotating at a predetermined RPM. A fourth step of checking whether the thread is positioned on a target track; If the sled is positioned on the target track, a servo control method of an optical disk reproducing apparatus, characterized in that comprising the step of performing a final search after outputting a feed control signal for stopping the sled. 2. The servo control method according to claim 1, wherein the feed control signal and the spindle control signal in the first and second steps are output at the same time. 3. The spindle control signal output to rotate the spindle motor at a specified RPM is output based on a table that defines the RPM of the spindle motor for each track. Servo control method for an optical disk reproducing apparatus. 4. A spindle control signal for locking rotation of the spindle motor is output when there is no difference between an FGP count value generated by driving the spindle motor and a prescribed RPM corresponding to a target track. 4. The servo control method for an optical disk reproducing device according to claim 3, wherein