JPH0676466A - Magneto-optical disk reproducing device - Google Patents

Abstract

PURPOSE:To prevent the rotation control from being impossible even if a magneto-optical disk is not recorded without providing a circuit demodulating preformat patterns recorded on the magneto-optical disk. CONSTITUTION:When the fact that a reproduction signal is not obtained is detected by a reproduction detection means 13, a spindle servo circuit 10 is actuated so that the rotation speed of a spindle motor 9 may be held and the counting of prescribed time is started by a timer means 14. When the fact the reproduction signal is obtained is not detected by the reproduction detection means 13 by the time when the counting is completed, the decision that a reproduction disk is not recorded is made. The signal reading operation from the disk is stopped or the reproduced location by a pickup is displaced to a prerecorded area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical disk reproducing apparatus for reproducing a magneto-optical disk on which preformat patterns for addresses and synchronizing signals are recorded in advance.

[0002]

2. Description of the Related Art A signal recorded on a magneto-optical disk is read by irradiating a magneto-optical disk whose signal is recorded by reversing the magnetization direction with a light beam and detecting the polarization direction of the reflected light. There is known a magneto-optical disk reproducing apparatus which reproduces the read signal to obtain a reproduced signal. As such a magneto-optical disk reproducing device,
CD-MO, which is a magneto-optical disk conforming to the CD standard
(Rewritable type) or CD-WO (writable only once) type has been developed.

By the way, in a recordable magneto-optical disk conforming to the CD standard, a groove of a pre-format pattern called a pre-groove, which is wobbled at 22.05 KHz, is formed in a spiral shape in advance. Tracking control of a writing light beam is performed using a pre-groove, or, for example, Japanese Patent Laid-Open No. 7908/1992.
As shown in Japanese Patent Publication No. 8, the rotation of the disk is controlled.

Further, the pregroove has 22.05.
Absolute Time In Pre-groove (ATIP) that becomes address information by FM modulating KHz
Is recorded on the entire surface of the disc, and the ATIP is used when accessing the recording position. Therefore, an ATIP decoder which decodes the ATIP is indispensable in a device corresponding to a magneto-optical disk having such a pre-groove.

[0005]

On the other hand, in the CD type magneto-optical disk, signal recording is performed by EFM (8-14 conversion) EFM signals. Then, the reproducing apparatus for the magneto-optical disk is configured so that the E
The rotation of the disc is controlled by using the FM signal. Therefore, in the magneto-optical disk on which the EFM signal has been recorded, the rotation control of the disk can be performed without demodulating the wobbling of the pre-groove.

However, since the EFM signal does not exist in the unrecorded magneto-optical disk, the rotation control of the disk cannot be performed without demodulating the wobbling of the pre-groove. For this reason, even a CD-only magneto-optical disk reproduction-only device has a problem that the disk rotation control becomes impossible and the drive goes out of control unless an ATIP decoder for demodulating the wobbling of the pre-groove is provided.

The present invention is a magneto-optical disk reproducing apparatus made in view of the above-mentioned problems, wherein the ATIP decoder is omitted without preventing the rotation control of the disk from being disabled. .

[0008]

According to the present invention, there is provided reproduction detecting means for detecting whether or not a reproduction signal obtained by reproducing a read signal from a disk is obtained, and a spindle for rotating the disk. A spindle control circuit for controlling the motor to rotate the disc at a specified speed, and for holding the rotation speed of the spindle motor when the reproduction detecting means detects that no reproduction signal is obtained; A timer circuit that starts time counting when it is detected by the detecting means that the reproduction signal is no longer obtained, and stops time counting when it is detected that the reproduction signal is obtained by the reproduction detecting means. And a stop state in which the signal reading operation from the disk is stopped when the timer circuit completes measuring a predetermined time. Or it has a reproduction position by the pickup so as to displace the pre-recorded Dido region.

[0009]

According to the present invention, when it is detected that the reproduction signal is not obtained, the rotation speed of the spindle motor is controlled to be maintained, and the reproduction signal is started by the start of the time measurement for the predetermined time. If it is not obtained, it is determined that the playback disc is unrecorded, and the signal reading operation from the disc is stopped, or the playback position by the pickup is displaced to the pre-recorded area, It prevents the disc rotation control from becoming impossible without demodulating the preformat pattern.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention, in which 1 is an RF for amplifying an EFM RF signal (high frequency signal) recorded on a disk 3 read by an optical pickup 2 and shaping the waveform. Amplifiers 4 drive the optical pickup 2 by an RF signal obtained through the RF amplifier 1 and focus control for focusing a laser beam for reading a signal from the disc 3 on a signal surface of the disc 3 and the laser beam. Of the pickup servo circuit 5 for controlling the feed of the optical pickup 2 in the radial direction of the disc 3 while performing a tracking control for making the optical disc follow the signal track of the disc 3, and a waveform shaping by the RF amplifier 1 A clock synchronized with the bits of the digital signal is reproduced from the obtained digital signal. That is a clock recovery circuit.

Reference numeral 6 denotes digital signal processing of the digital signal output from the RF amplifier 1 based on the bit clock reproduced by the clock reproducing circuit 5 and a reference clock of crystal oscillation accuracy, and various data recorded on the disk 3 is processed. It is a digital signal processing circuit for detecting and demodulating. The digital signal processing circuit 6 detects the frame sync signal indicating the beginning of the frame of the recording signal of the disk 3 from the digital signal of the EFM signal output from the RF amplifier 1, and performs the sync detection / EFM demodulation for performing the EFM demodulation. A circuit 7 and a sub-code separation unit that separates sub-code data from the digital data EFM-demodulated by the period detection / EFM demodulation circuit 7 and demodulates a Q code (Q channel data) included in the sub-code data. A Q code demodulation circuit 8 is provided.

Reference numeral 9 is a spindle motor for rotating the disk 3, and 10 is a spindle servo circuit for controlling and driving the spindle motor 9.

The spindle servo circuit 10 includes an EFM.
A rough servo that detects the pulse width of the shortest pulse (or the longest pulse) in the signal based on the count number of the reference clock and controls the rotation speed of the spindle motor 9 so that the pulse width becomes a predetermined length; A PLL servo that controls the rotation speed of the spindle motor 9 with high accuracy by comparing the phase of the clock and the reference clock is provided.
Then, in the spindle servo circuit 10, the cycle of the frame synchronization signal of the EFM signal detected based on the count number of the reference clock is out of the predetermined cycle range because the rotational speed of the disk is largely deviated from the specified speed. If it is in the rough servo state, the rough servo brings the rotation speed of the disk close to the specified speed, so that the cycle of the frame synchronization signal falls within the predetermined cycle range,
When it becomes a state where it can be pulled into the PLL servo, it is switched to the PLL servo state.

Reference numeral 11 denotes a microcomputer for performing various system controls, in which various programs for controlling the entire system including basic operations such as a disc reproducing method, various access methods, and a focusing introducing method for the optical pickup 2 are written. It is a configured system control circuit. In the system control circuit 11, a buffer memory 12 into which the latest Q code demodulated by the subcode separation / Q code demodulation circuit 8 is written, and a Q code written in the buffer memory 12 are monitored and reproduced. Depending on the reproduction detecting means 13 for detecting the state, the timer means 14 for measuring a predetermined time by using the detection output of the reproduction detecting means 13 as a trigger, the completion of the time counting by the timer means 14 and the detection output of the reproduction detecting means 13. Control of the spindle servo circuit 10 and system control circuit 11
Each unit except for the above and an instruction unit 15 for instructing control of power supply to the optical pickup 2 are provided.

The reproduction detecting means 13 detects the timing at which the Q code is written in the buffer memory 12 while the spindle motor 9 is being rotated by the spindle servo 10 to reproduce the disc. A reproducible state is detected by detecting whether it is in a reproducible state or a reproducible state in which no reproduction is performed, and when the reproducible state is detected, a start signal for starting timing of the timer circuit 14 is generated. When this is done, a stop signal for stopping the time counting of the timer circuit 14 is generated.

When the reproduction detection circuit 13 detects the reproduction disabled state, the command means 15 causes the spindle servo circuit 10 to control the spindle motor 9 to the rough servo state and causes the spindle servo circuit 10 to rotate the spindle motor 9. A rotation holding signal that is a command for controlling the optical pickup 2 is generated, and when the timer means 14 completes the timing, the spindle servo circuit 10 controls the spindle motor 9 to stop and the optical pickup 2 Generates a stop signal as a command for controlling the control of stopping the emission of the laser light and the control of the operation of each circuit except the system control circuit 11.

Now, when the recorded magneto-optical disk is reproduced, the spindle servo circuit 10 includes the RF amplifier 1
An EFM signal of a recording signal of the disc obtained via
A reference clock of crystal oscillation accuracy and a reproduction clock obtained by the clock reproduction circuit 5 are supplied. Therefore, the spindle servo circuit 10 performs EF by rough servo.
The rotation of the spindle motor 9 is controlled so that the pulse width of the shortest pulse in the M signal becomes a predetermined length, and then PL
The rotation of the spindle motor 9 is controlled by the L servo so that there is no phase deviation between the reproduction clock and the reference clock.

By the way, E output from the RF amplifier 1
For the FM signal, the frame detection signal is sequentially detected by the synchronization detection / EFM demodulation circuit 7, EFM demodulated, and then the subcode data is separated by the subcode separation / Q code demodulation circuit 8 to demodulate the Q code. . Then, the demodulated Q code is written in the buffer memory 12 at any time, and the writing state of the Q code in the buffer memory 12 is monitored by the reproduction detecting means 13.

Here, the reproduction detecting means 13 has a predetermined timing (having a time width) set in advance on the basis of the timing when the Q code is obtained by the sub code separation / Q code demodulation circuit 8 in the normal reproduction state. However, it is determined that the latest Q code cannot be obtained and playback is not being performed, but the Q code cannot be obtained due to dropout or reading error, and the disc recording signal exists. Even if the portion to be reproduced is being reproduced, the reproduction detecting unit 13 may determine that the reproduction is not being performed. In this case, the timer means 14 starts to count the time, but the timer means 14 is set in consideration of the fact that the Q code cannot be obtained due to such a cause, and the Q code cannot be obtained. Is set so that the time measurement will not be completed unless it continues for a predetermined long period.

When the reproduction clock cannot be obtained from the clock reproduction circuit 5 due to dropout or the like, and the spindle servo circuit 10 becomes unable to perform the PLL servo, the spindle servo circuit 10 switches to the rough servo state. , The Q code cannot be obtained from the sub code separation / Q code demodulation circuit 8, and the reproduction detecting means 13 determines that the reproduction is impossible. Therefore, the rotation holding signal is generated from the command means 15, and the rotation of the spindle motor 9 is held by the spindle servo circuit 10.
In this state, the signal reading is started again, and the clock recovery circuit 5 is added to the spindle servo circuit 10.
When the reproduction clock from the above is supplied, the spindle servo circuit 10 returns to the PLL servo state again, so that the Q code is demodulated again by the sub code separation / Q code demodulation circuit 8 and reproduction detection is performed. Means 1
It becomes possible to determine that the reproducible state has been reached by 3, and the steady state is restored.

Therefore, during reproduction of the recorded magneto-optical disk, the spindle motor 9 is driven by the PLL servo, and the disk 3 is rotationally driven at the rated speed (constant linear velocity), and the reproducing operation is normally performed. Be seen.

On the other hand, when the unrecorded magneto-optical disk is reproduced, neither the EFM signal nor the reference clock and the reproduction clock are supplied to the spindle servo circuit 10. Therefore, the spindle servo circuit 10 accelerates the rotation speed of the disk by the rough servo because the rotation of the disk is started at the start of reproduction, but it is not transferred to the PLL servo.

By the way, in this state, since the EFM signal is not input to the digital signal processing circuit 6 and the Q code is not demodulated by the sub code separating / Q code demodulating circuit 8, the reproduction detecting means 13 reproduces it. When it is determined that the state is not possible, the timer means 14 starts the time measurement, the rotation holding signal is generated from the command means 15, and the spindle motor 9 is driven by the spindle servo circuit 10 to keep the rotation speed in the rough servo state. .
Then, since the EFM signal is not input to the digital signal processing circuit 6 and the reproduction detection means 13 continues to determine the reproduction disabled state, the spindle motor 9 is held by the spindle servo circuit 10 in the rough servo state to maintain the rotation speed. While being driven, the timer means 14 eventually completes counting the predetermined time. Therefore, the stop signal is generated from the command means 15, the rotation of the spindle motor 9 is stopped through the spindle servo circuit 10, the emission of the laser light of the optical pickup 2 is stopped, and the operation of each circuit is stopped. .

Therefore, when the unrecorded magneto-optical disk is reproduced, the spindle motor 9 is accelerated in rotation speed, and thereafter, the rotation speed is maintained by the rough servo for a predetermined time measured by the timer means 14, and in the meantime. Q
If the code is not obtained, it is determined that the code has not been recorded, and the reproducing operation is stopped.

Even when the recorded magneto-optical disc is reproduced, when the reproduction of the recorded portion is completed and the reading position of the disc by the optical pickup 2 advances to the unrecorded portion area, the above-mentioned unrecorded portion is not recorded. Similarly to the reproduction of the magneto-optical disc, the reproduction operation is stopped.

On the other hand, in the magneto-optical disk conforming to the CD standard, as shown in the sectional view of FIG. 2, music and data are recorded on the inner peripheral side in front of the recordable area where the user records signals. There is a type of disc having a pre-recorded area (ROM area) which is recorded in advance. In this type of disc, since information (presence / absence and address) of the pre-recorded area is recorded in the lead-in, the disc reproduced by reproducing the lead-in has the pre-recorded area. It is possible to detect whether it is a type or not.

FIG. 3 is a circuit block diagram showing another embodiment of the present invention, in which the Q code cannot be obtained until the timer means 14 completes the counting of a predetermined time, and the optical pickup 2 reads the disc reading position. The operation when it is determined that the (playback position) is the unrecorded area is different from that of FIG. In the magneto-optical disk reproducing apparatus shown in FIG. 3, when the time counting by the timer means 14 is completed,
The optical pickup 2 is temporarily displaced to the initial position on the innermost side of the disc that is mechanically set. In this case, the optical pickup 2 is forcibly displaced to the inner peripheral side, and the switch detecting means 17 detects that the switch 16 indicating the initial position is closed by the optical pickup 2 and the optical pickup 2 is moved to the initial position. It is detected that it has been displaced to.

When the optical pickup 2 is displaced to the initial position, the reproduction is resumed from the lead-in of the disc according to the normal reproduction procedure. In this way, the disk is returned to the state in which the rotation control is possible. Then, the lead-in is reproduced, and the disc discriminating means 18 discriminates whether or not the disc is a ROM area disc having a pre-recorded area. When the disc discriminating means 18 discriminates that the disc is a ROM area disc, the optical pickup 2
The reproduction position by is displaced to the pre-recorded area, and the reproduction of that area is started.

On the other hand, the disc discriminating means 18 causes the ROM
If it is determined that the disc is not the area-equipped disc, the reproducing operation is stopped.

[0030]

As described above, according to the present invention, the reproducing operation is stopped when there is no recording signal on the magneto-optical disk. Therefore, the magneto-optical disk can be recorded without using the preformat pattern. Therefore, it is possible to provide a reproducing apparatus capable of reproducing a magneto-optical disk without providing a circuit for demodulating a preformat pattern without the rotation control being disabled.

[Brief description of drawings]

FIG. 1 is a circuit block diagram showing an embodiment of the present invention.

FIG. 2 is a cross-sectional configuration diagram of a magneto-optical disk.

FIG. 3 is a circuit block diagram showing another embodiment of the present invention.

[Explanation of symbols]

 6 Digital Signal Processing Circuit 9 Spindle Motor 10 Spindle Servo Circuit 11 System Control Circuit 13 Playback Detection Means 14 Timer Means 15 Command Means

Claims (2)

[Claims] 1. A magneto-optical disk reproducing apparatus for reproducing a magneto-optical disk in which pre-format patterns for addresses and synchronizing signals are recorded in advance, which comprises a spindle motor for rotating the disk and a disk. Reproduction detection means for detecting whether or not a reproduction signal obtained by reproducing the read signal of the above is obtained, and the spindle motor is controlled to rotate the disk at a prescribed speed, and the reproduction detection means is used to reproduce the reproduction signal. And a spindle control circuit for controlling the rotation speed of the spindle motor to be held when it is detected that no reproduction signal is obtained, and starts the time measurement when it is detected that the reproduction signal is no longer obtained. At the same time, when it is detected that the reproduction signal is obtained by the reproduction detecting means, A magneto-optical disk reproducing apparatus comprising: a timer circuit for stopping time, and a stop state in which a signal reading operation from a disk is stopped when the timer circuit completes measuring a predetermined time. . 2. A type of optical disc having a pre-recorded area in which music and data are pre-recorded on a part of an unrecorded magneto-optical disc in which pre-format patterns for addresses and sync signals are pre-recorded. A magneto-optical disk reproducing device for reproducing a magnetic disk,
A spindle motor for driving the disc to rotate, a reproduction detecting means for detecting whether or not a reproduction signal obtained by reproducing the read signal from the disc is obtained, and controlling the spindle motor to define the disc. A spindle control circuit for controlling the rotation speed of the spindle motor so as to maintain the rotation speed of the spindle motor when the reproduction detecting means detects that the reproduction signal is not obtained, and the reproduction detecting means obtains the reproduction signal. A timer circuit for starting the time measurement when it is detected that the time has run out, and for stopping the time measurement when it is detected that the reproduction signal is obtained by the reproduction detection means. Displace the playback position by the pickup to the pre-recorded area when the measurement of the predetermined time is completed Magneto-optical disk reproducing apparatus, characterized in that the.