JP2001307414A - Disk recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the erasure of recorded data on a disk by detecting the absolute location of a pickup without turning a laser ON, detecting the number of revolutions of the disk to control laser ON or laser OFF. SOLUTION: A disk recording and reproducing device is provided with a disk 1 which is rotated by a spindle motor 4 and recorded data are erased when it is heated to a temperature equal to or higher than a prescribed temperature and a detecting means 20 which detects rotation information of a thread motor 5 that drives a pickup 2. Moreover, the disk recording and reproducing device is provided with a storage means 101 which stores a pulse address obtained by counting the signals that is increased or decreased in accordance with the rotating direction of the motor 5 detected by the means 20, a comparison means 101 which compares the present number of revolutions of the motor 4 and a prescribed number of revolutions that is set for the disk located at the pulse address and a control means 8 which allows laser irradiation of the disk from the pickup.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk recording / reproducing apparatus for a magneto-optical disk or an optical disk, and more particularly to a disk recording / reproducing apparatus which prevents data recorded on the disk from being erased when irradiated with a laser beam. Related to the device.

[0002]

2. Description of the Related Art Conventionally, since a disk recording / reproducing apparatus does not know the absolute position of a pickup when a power supply is turned on, a disk reproducing operation is performed at that position and the position information of the disk is read or the pickup is operated by using a mechanical switch. The method of knowing the position is taken.

FIG. 4 is a diagram showing the relationship between the number of rotations of a spindle motor set in each zone of a disk.

[0004]

However, when a disk is used in which recorded data is erased when the temperature rises to a predetermined temperature or higher, a disk reproducing operation is performed as in the former case to obtain the position information of the disk. When reading is performed, the laser is turned ON at a predetermined rotational speed or less, and the recorded data is erased. When a mechanical switch is used as in the latter case, for example, as shown in FIG. 4, the pickup can be moved to zone 0, and even if the position of the pickup can be confirmed, the laser is turned on at a predetermined rotation number or less. Then, the recorded data is erased in the same manner as described above.

That is, in any case, there is a possibility that the temperature of the recording layer reaches the Curie point or more due to the laser irradiation and the recorded data is erased, and it is necessary to control the rotation speed of the spindle motor.

Normally, the rotation of a spindle motor used in a disk recording / reproducing apparatus is controlled by feeding back FG pulse information of the spindle motor to control the rotation of the spindle motor.
There are three modes: a rotation control mode, a PLL rotation control mode in which the rotation is detected by detecting a synchronization signal recorded on the disk, and a forced rotation mode in which the spindle motor is forcibly rotated by applying a constant voltage. A motor is used, and how fast the motor itself is rotating can be measured instantaneously and instantaneously, and the rotation of the spindle motor can be controlled.

However, when the disk is started, the spindle motor is forcibly accelerated for a certain period of time, and after confirming that a predetermined number of revolutions has been reached with the FG pulse, the mode is switched to the PLL control. Not controlled according to the number of revolutions of the disk. The reason is that, in general, the reproduction power of the laser is very low as compared with the recording power, so that there is very little risk of erasing data, and precise control is not required. Also, the laser is OF
Precise control is not performed at the timing of F for the above reason.

SUMMARY OF THE INVENTION An object of the present invention has been proposed in view of the above-mentioned various problems. It is possible to detect the absolute position of a pickup without turning on a laser and to detect the rotational speed of a disk. It is an object of the present invention to provide a disk recording / reproducing apparatus which controls laser ON or laser OFF to prevent erasure of recorded data on the disk.

[0009]

The present invention employs the following means in order to solve the above-mentioned problems.

The first means uses a disk which is rotated by a spindle motor and erases recorded data when heated to a predetermined temperature or higher, and includes a detecting means for detecting rotation information of a thread motor for driving a pickup. A disk recording / reproducing apparatus comprising: a storage unit for storing a pulse address obtained by counting a signal that is increased or decreased according to a rotation direction of the sled motor detected by the detection unit; and a current rotation speed of the spindle motor. Comparing means for comparing a predetermined number of rotations set in the disk located at the pulse address; and, as a result of the comparison, when the current number of rotations is equal to or higher than the predetermined number of rotations, the laser irradiation from the pickup to the disk is performed. And a control means for permitting.

A second means is the first means, wherein the predetermined position detecting means detects that the pickup has reached a predetermined position in the radial direction of the disk when the apparatus is started, and the predetermined position detecting means. A pulse address initial value setting means for setting the pulse address to an initial value when the predetermined position is detected.

[0013] The third means is the first means or the second means, wherein when the laser is irradiated from the pickup to the disk, the pulse stored by the address detected from the disk by the pickup is stored. A pulse address correcting means for correcting an address is provided.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram showing the configuration of a disk recording / reproducing apparatus according to this embodiment.

In FIG. 1, reference numeral 1 denotes a disk which normally receives gravity in the G1 direction as shown in the drawing when it is mounted on the apparatus, but depending on the attitude of the apparatus, it may move in the G2 direction or in the opposite direction. Also receives gravity. 2 is pickup, 3
Numerals are magnetic heads, which are provided to face each other with the disk 1 interposed therebetween, and are provided so as to be integrally movable along the surface of the disk 1 in the center direction of the disk 1 and in the opposite direction. Reference numeral 4 denotes a spindle motor composed of an FG motor for rotating the disk 1.

Here, the disk 1 is recorded by laser strobe magnetic field modulation recording, receives a magnetic field based on a data signal from the magnetic head 3, and performs a predetermined operation on the disk 1 based on the pulsed laser beam from the pickup 2. When the location is raised to a temperature equal to or higher than the Curie point, it is perpendicularly magnetized based on the direction of the magnetic field.
Thereafter, the temperature of the recording portion drops to a temperature lower than the Curie point, whereby the magnetization is fixed and held at the magnetization having the magnetization direction. Since the laser beam is a pulse light emission, the pitch of the recorded signal is very narrow, and high density recording is possible.

In the pickup 2, the rotational drive of the sled motor 5 is converted into a linear drive, and the above-described movement is enabled by an intermediate transmission means (not shown). The drive signal for the sled motor to the sled motor 5 has a speed
PW based on a signal generated by the digital servo processing circuit 10 based on a signal from the moving distance calculation circuit 12
It is generated based on the PWM signal generated by the M signal generation circuit 13.

Further, inside the thread motor 5, a ring-shaped magnet in which N poles and S poles are alternately magnetized, rotates integrally with the rotor so as to face the magnet, and at a predetermined interval (a predetermined interval). Two Hall elements 11 (11a, 11b) for obtaining rotation information are provided at an angle. The output signals of these elements 11a and 11b are sent to a speed / movement distance calculation circuit 12, and the speed / movement distance calculation circuit 12 calculates the movement speed of the pickup 2 in the center direction of the disk 1 and in the opposite direction based on the output signal. And the moving distance are calculated, and the calculation result is sent to the digital servo processing circuit 10. Further, the PWM signal generation circuit 13 generates a PWM signal based on a signal from the digital servo processing circuit 10 and sends it to the PWM driver 14, and drives the thread motor 5 by a thread motor drive signal from the PWM driver 14. .

Here, two Hall elements 11a, 1
1b are output signals P1 and P2, respectively.
One output signal P2 is π /
Two Hall elements 11a and 11b are disposed opposite to a rotating plate alternately magnetized at equal intervals so that two Hall elements 11a and 11b rotate synchronously with the output shaft of the motor so as to advance by two. Based on the output signals P1 and P2, the speed / movement distance calculation circuit 1
2 generate pulse signals Q1 and Q2.

The pickup 2 has an objective lens 2 therein.
1 and the objective lens 21 is also provided with an RF
A PWM signal is generated by a PWM signal generation circuit 13 based on a signal generated by the digital servo processing circuit 10 based on a signal from the processing circuit 6, and is driven by an objective lens drive signal from a PWM driver 14. .

Further, the pickup 1 has a disc 1
First for two RF signals to detect reflected light from
A photodetector 22 and a second photodetector 23 for obtaining a tracking error signal and a focus signal are provided. The light detection signals output from these light detectors 22 and 23 are sent to the RF processing circuit 6 and are converted into an IV converter (current signal → voltage signal).

The RF detected by the first photodetector 22
The signal is composed of two signals whose phases of the corresponding light detection signals are exactly opposite to each other. After being sent to the RF processing circuit 6, a difference signal (substantial sum signal) between the two signals is obtained by the RF processing circuit 6. , And AGC processing is performed and sent to the signal processing circuit 9. In the signal processing circuit 9, processing such as error correction, deinterleaving, NRZI conversion, and Viterbi decoding is performed, and the signal is sent to the interface 19 for subsequent connection.

Each light detection signal detected by the second photodetector 23 is also sent to the RF processing circuit 6, where each error signal is generated. Further, each error signal is sent to an A / D converter (ADC) 7 where it is A / D converted, and the converted digital signal is sent to a digital servo processing circuit 10 to generate a final error signal.

The head motor 16 of the magnetic head 3
Is controlled by the control microcomputer 8 and is lowered to the disk surface side by the magnetic head lifting / lowering drive circuit 18 so as to slide on the disk 1 at the time of recording. It is raised in a direction away from the disk 1.

Here, the digital servo processing circuit 10 mainly includes a DSP (digital signal pr).
ossor).

In the digital servo circuit 10, a synchronization signal obtained from the RF signal input to the signal processing circuit 9 is subjected to PLL processing based on a master clock, and the PLL-processed signal is sent to a PWM signal processing circuit 13. The rotation of the spindle motor 4 is controlled via a spindle motor driver 15 after being converted into PWM.

The spindle motor 4 is controlled by the above-described PLL circuit when recording or reproduction is being performed, that is, when tracking is being performed. Controlled by servo.

Next, the FG servo will be described in detail.
A drive signal is output from the spindle motor driver 15, and the spindle motor 4 is rotationally driven by the drive signal. A signal related to the rotation of the spindle motor 4 itself is fed back to the spindle motor driver 15 from the spindle motor 4, where the signal is shaped (FG signal) and sent to the signal processing circuit 9. The signal processing circuit 9 compares the desired rotation speed of the spindle motor 4 in the zone where the pickup 2 is located with the fed-back rotation speed, and generates an error signal. A source signal of the spindle motor drive signal is generated by the digital servo processing circuit 10 for this error signal, and is sent to the spindle motor driver 15 via the PWM signal generation circuit 13. The FG servo is performed in the above loop.

The above FG signal is supplied to the control microcomputer 8
When the rotation speed of the spindle motor 4 is lower than the desired rotation speed of the zone where the pickup 2 is located by a certain value or more, the laser beam is forcibly emitted by the LD driver 24 by a signal from the control microcomputer 8. Stop.

After the tracking error signal is also input to the PWM signal generation circuit 13 and converted into a PWM signal, focus control and tracking control are performed via the PWM driver 14.

The speed / movement distance calculation circuit 1 described above is used.
The speed value input from 2 is subjected to tracking control in consideration of the tracking error signal described above. That is, the tracking servo is switched from the pickup 2 to the RF processing circuit 6
The main loop of ADC 7 → digital servo processing circuit 10 → PWM signal generation circuit 13 → PWM driver 14 → pickup 2 and pickup 2 (Hall element 1
The control is performed by two sub-loops: 1) a speed moving distance calculation circuit 12, a digital servo processing circuit 10, a PWM signal generation circuit 13, a PWM driver 14, and a pickup 2.

Here, the two loops will be described in detail with reference to FIG.

As described above, in the pickup 2, the tracking error signal and the offset signal are generated from the reflected light of the main beam and the sub beam. The tracking error signal TE or the offset signal ofs is input to a non-inverting input terminal of a comparator 101 provided in the digital servo processing circuit 10. on the other hand,
An output signal E (speed signal E) from the speed / movement distance calculation circuit 12 is input to the inverting input terminal of the comparator 101. In the comparator 101, the tracking error signal TE or the offset signal ofs and the speed / movement distance calculation circuit 1
2 outputs a difference signal e from the speed signal E, and the amplifier 1 also provided in the digital servo processing circuit 10.
02 is input. The drive signal e0 (e0 = A · e1) amplified A times by the amplifier 102 is used as the PWM signal generation circuit 1.
The motor 3 is applied to the sled motor 5 via the PWM driver 14 and is driven to rotate.

When the thread motor 5 is driven to rotate by the drive signal e0, the two Hall elements 11
Signals P1 and P2 are output from a and 11b. The speed / movement distance calculation circuit 12 generates a speed signal E corresponding to the rotation speed of the sled motor 5 from the signals P1 and P2, and the speed signal E is input to the comparator 101 as described above.

With the above configuration, when tracking control is performed by the main loop, the sled motor 5 is controlled by the sub-loop.

In the present apparatus, at the time of a long search, in order to accurately reach the target track position, instead of counting the number of zero crossings, the pulse address calculation section 101 provided in the digital servo processing circuit 10 has a speed / movement distance calculation circuit. The pulse signal Q1 or Q2 output from 12 is counted. This eliminates erroneous counting of zero crossings due to eccentricity and the fact that the zero crossing cannot be read due to an increase in the moving speed of the pickup.

Next, in the digital servo processing circuit 10 and the control microcomputer 8, the O
The processing procedure from N to laser irradiation will be described with reference to FIG.

First, when the power is first turned on, the TOC
A rough search is performed in a (Total Of Contents) area. Here, the rough search is to move the pickup 2 by the sled motor 5 until the lead-in switch 20 provided opposite to the surface of the disk 1 that switches near the TOC area of the disk 1 switches.
In step 1, when the lead-in switch 20 is turned on, the detection signal is sent to the digital servo processing circuit 10, the pickup 2 is controlled via the PWM signal generation circuit 13 and the PWM driver 14, and stopped near the TOC area. Next, in step 2, the digital servo processing circuit 10 sets the pulse address of the pickup 2 at this position to an initial value "0", and stores and manages this pulse address "0" as position information.

Next, at the time of the long search, in step 3, the pulse signal Q1 (Q2) changing with the rotation of the sled motor 5 is counted. In step 3,
When moving in the inner circumferential direction, the pulse address arithmetic circuit 101 adds a pulse address each time a pulse count is performed. When moving in the outer circumferential direction, the pulse address is subtracted and stored each time the pulse count is performed, while the pickup 2 is moved to a target position.

Similarly, at the time of kicking, the pulse count is updated to update the pulse address. Further, similarly, at the time of play, the pulse address is updated and stored in accordance with the moving direction of the pickup 2 in consideration of the fact that the slide feed is rotated in the reverse direction due to the influence of eccentricity and the like, when the pulse is counted.

Next, in step 4, the pickup 2
Is determined to have reached the predetermined position, and if not, the processing from step 3 is repeated. If reached,
In step 5, the rotation speed of the spindle motor 4 at the current position of the moved pickup 2 is detected and fed back to the digital servo processing circuit 10 via the spindle motor driver 15 and the signal processing circuit 9. In step 6, the detected rotation speed is compared with a predetermined rotation speed set in the disk zone belonging to the current position of the pickup 2, and the fed-back rotation speed reaches the predetermined rotation speed set in the zone of the current position. Determine whether you have done. If it has reached, in step 7, the laser driver 24 is turned on under the control of the step control microcomputer 8 to start laser irradiation.

Thereafter, at step 8, the control microcomputer 8
Sends an instruction to the digital servo processing circuit 10 to perform a focus search (up and down of the pickup lens). The digital servo processing circuit 10 closes the focus servo when focus is achieved. Next, when the focus servo is closed, the optical detection signal from the pickup 2 is generated by the RF processing circuit 6 to generate an error signal, converted into a digital signal through the ADC 7, and the digital signal is equalized by the digital servo processing circuit 10. After being converted into a PWM signal by the PWM signal generation circuit 13, the focus coil of the pickup 2 is driven via the PWM driver 14. In the same processing as described above, the tracking servo and the slide servo are turned on, the spindle motor is controlled by the FG, and once the address which is the disk position data is read, the spindle motor is PLL controlled.

Thereafter, the processing from step 6 is repeated, and the current rotational speed is monitored by comparing the constantly detected rotational speed of the spindle motor with the predetermined rotational speed of the zone at the current pulse address. If the number of revolutions fed back does not reach or does not reach the predetermined number of revolutions set in the zone at the current position in step 6, the process proceeds to step 9, and in step 9, laser irradiation is already performed. If so, the laser irradiation is stopped and the processing from step 5 is repeated. In step 7, when laser irradiation becomes possible, in step 10, the address on the disk 1 is read from the pickup 2. Then
In step 11, the read address is compared with the stored pulse address, and if a difference occurs, in step 3, the pulse address is corrected and stored.

As described above, according to the invention of this embodiment, since the pulse address is constantly managed after the start-up, the current position of the pickup 2 corresponding to the disk 1 is always grasped before the laser irradiation. It is possible to know whether or not the disk 1 at the current position has reached the predetermined rotational speed of the zone to which the disk 1 belongs. Therefore, it is possible to prevent the disk 1 from being irradiated with the laser beam at a predetermined rotation number or less of the spindle motor 4 and heated to a predetermined temperature or more and the recorded data is erased.

According to the present embodiment, when the address can be read by the pickup 2 after the laser is turned on, the digital servo processing circuit 10
The address detected by the pickup 2 is compared with the previously stored pulse address, and if there is a difference, the stored pulse address is corrected. The error due to the reading error of the pulse signal due to the error can be eliminated.

[0046]

According to the first aspect of the present invention, since the pulse address is always managed, the pulse address is controlled before the laser irradiation.
The current position corresponding to the pickup disk can always be grasped, and it can be known whether the disk at the current position has reached the predetermined rotation speed of the zone to which the disk belongs. It is possible to prevent the recorded data from being erased due to the laser irradiation and the heat rise above a predetermined temperature.

According to the second aspect of the present invention, the pulse address is set to an initial value and managed when the pickup reaches a predetermined position in the radial direction of the disk at the time of startup. Can always store and manage the pulse address.Even if the device is restarted from the stop state, the pulse address is constantly increased or decreased according to the movement of the pickup in the radial direction based on the managed pulse address. The pulse address can be quickly grasped.

According to the third aspect of the present invention, the pulse address is corrected by the address obtained at the time of laser irradiation, so that a correct pulse address can always be secured.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a disk recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining control by a main loop and a sub loop of tracking servo in the disk recording / reproducing apparatus according to the embodiment.

FIG. 3 is a diagram showing an O of a reed switch 20 in the digital servo processing circuit 10 and the control microcomputer 8 shown in FIG.
It is a figure showing the processing procedure from N to laser irradiation.

FIG. 4 is a diagram showing a relationship with the number of rotations of a spindle motor set in each zone of the disk.

[Description of Signs] 1 Disc 2 Pickup 21 Objective Lens 22 First Photodetector 23 Second Photodetector 3 Head 4 Spindle Motor 5 Thread Motor 6 RF Processing Circuit 7 ADC 8 Control Microcomputer 9 Signal Processing Circuit 10 Digital Servo Processing Circuit 101 Pulse address calculation circuit 11 Hall element 12 Speed / movement distance calculation circuit 13 PWM signal generation circuit 14 PWM driver 15 Spindle motor driver 16 Head motor 17 Head drive circuit 18 Head lifting / lowering drive circuit 19 Interface 20 Lead-in switch

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G11B 19/04 501 G11B 19/04 501A 501Q 21/08 21/08 C

Claims (3)

[Claims] 1. A disk which is rotated by a spindle motor and from which recorded data is erased when heated to a predetermined temperature or higher is used, and which has a detecting means for detecting rotation information of a sled motor driving a pickup. In the apparatus, storage means for storing a pulse address obtained by counting a signal that is increased or decreased according to the rotation direction of the sled motor detected by the detection means, and a current rotation number of the spindle motor and the pulse address. Comparing means for comparing a predetermined number of rotations set in a located disk, and control means for permitting laser irradiation from the pickup to the disk when the current number of rotations is equal to or higher than the predetermined number of rotations as a result of the comparison. And a disk recording / reproducing apparatus. 2. The apparatus according to claim 1, further comprising: a predetermined position detecting unit configured to detect that the pickup has reached a predetermined position in a radial direction of the disk when the apparatus is started; 2. A disk recording / reproducing apparatus according to claim 1, further comprising a pulse address initial value setting means for setting a pulse address to an initial value. 3. A pulse address correcting means for correcting the stored pulse address based on an address detected from the disk by the pickup when laser irradiation is performed on the disk from the pickup. 3. The disc recording / reproducing apparatus according to claim 1, wherein