JP2002329322A - Disk recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent problems caused by occurrence of quick change of an environmental temperature or disturbance of a servo with respect to a disk recording and reproducing device where a disk 1 is irradiated with laser light from an optical head 4 to record or reproduce a signal on or from the disk 1. SOLUTION: In the disk recording and reproducing device, a system controller 10 detects it on the basis of temperature data obtained from a temperature sensor 16 whether or not there is probability that the signal has been not normally recorded; and when there is probability that the signal has been not normally recorded, the signal is actually reproduced to discriminate whether the signal can be normally reproduced or not. When it is discriminated that the signal can be normally reproduced, signal recording is continued as it is, but when it is discriminated that the signal cannot be normally reproduced, file management information corresponding to a recording area where abnormality has occurred is invalidated.

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 irradiating a disk with laser light from an optical head to record a signal on the disk or reproduce a signal from the disk.

[0002]

2. Description of the Related Art Conventionally, rewritable, large-capacity, and highly reliable magneto-optical disks have been developed as recording media for such disk recording / reproducing apparatuses. It is widely used as an external memory. Particularly in recent years, lands (17) and grooves (18) are alternately formed on the signal surface of the magneto-optical disk (1) as shown in FIG. 4, and signals are applied to both the lands (17) and the grooves (18). Techniques for recording and increasing the recording density have been developed.

The land (17) and the groove (18) meander (wobble) as shown in the figure, and the meandering frequency is FM-modulated at a predetermined center frequency. By controlling the rotation of the magneto-optical disk so that the detected wobble signal always has the center frequency, constant linear velocity control is realized. Further, the wobble signal is subjected to FM modulation as described above and contains various information (wobble information) such as address information. At the time of signal reproduction, various control operations are realized based on the wobble information. You.

In a disk recording / reproducing apparatus of the laser pulse magnetic field modulation type, a magneto-optical disk is irradiated with a laser beam when reproducing a signal, and the magneto-optical disk is also irradiated with a laser beam when recording a signal. Then, the magneto-optical disk is locally heated. Further, in a magneto-optical disk utilizing magnetic super-resolution, the laser power for signal reproduction is increased, and signal reading is started when the temperature of the beam spot area reaches a predetermined value. Since the laser power at the time of signal reproduction is set lower than the laser power at the time of signal recording, there is no possibility that the recorded signal will be damaged due to the signal reproduction.

[0005] In a disk recording / reproducing apparatus, as shown in FIG.
(Recording power) and the power of the laser beam at the time of signal reproduction (reproduction power) have optimum values Pwo and Pro, respectively. If the laser power deviates from the optimum value, the bit error rate Rb of the reproduction signal increases and the bit error increases. If the rate exceeds a certain prescribed value Rbt, normal reproduction operation becomes difficult.

Therefore, conventionally, at the time of system startup, a signal is reproduced while gradually changing the reproduction power, and an error rate is calculated, or the recording power is gradually increased, for a test track provided in advance on the magneto-optical disk. A method has been proposed in which a signal is recorded while changing the data rate, an error rate of the reproduced signal is calculated, and an optimum reproduction power or recording power that minimizes the error rate is searched.

[0007]

However, in a disk recording / reproducing apparatus, distortion of an optical head housing and parts, displacement of an optical sensor, change of a laser wavelength, and the like occur due to a sudden change in environmental temperature. However, these factors may cause the laser power to deviate from the optimum value. If this deviation increases, the error rate of the reproduced signal exceeds the threshold value Rbt, and error correction becomes impossible. Also, when an external impact is applied, the focus and tracking servos are disengaged and normal signal recording and signal reproduction cannot be performed. Similarly, the error rate of the reproduced signal exceeds the threshold value Rbt, and an error occurs. Correction becomes impossible. For example, in the case of a video signal, error correction becomes impossible, thereby causing image disturbance. Particularly in the case of a digital video signal, the image disturbance may be trailed, and the system may fail. There is.

Accordingly, an object of the present invention is to provide a disk recording / reproducing apparatus which can prevent a problem caused by a sudden change in the environmental temperature or a servo disturbance as described above. That is.

[0009]

A disk recording / reproducing apparatus according to the present invention generates control means for controlling a signal recording operation and a signal reproducing operation, and file management information including an address of a recording signal at the time of signal recording. Recording means for recording on a disc, detection means for detecting an environmental condition that affects the signal recording operation, and when the environmental condition exceeds a predetermined threshold value in the process of signal recording, the recording signal at that time is recorded. Determining means for reproducing a signal from a recording area including an address to determine whether normal reproduction can be performed; and a recording area in which an abnormality has occurred when it is determined that normal reproduction cannot be performed. Invalidation means for invalidating the file management information of

As the environmental conditions to be detected by the detecting means, the amount of change in the ambient temperature of the optical head and the magnitude of the impact force on the optical head can be adopted. Exceeding the threshold value can be detected by the fact that the servo has deviated. Further, the determination of the occurrence of the abnormality by the determination means can be performed by determining whether or not error correction of the reproduced signal is possible.

In the disk recording / reproducing apparatus of the present invention, signals such as video signals and audio signals and file management information including addresses of recording signals are recorded on the disk during the signal recording process. In the process of signal recording, the detecting means always detects an environmental condition that affects the signal recording operation, and when the environmental condition exceeds a predetermined threshold, includes the address of the recording signal at that time. It is determined whether or not normal reproduction can be performed by reproducing a signal from the recording area. As a result, when it is determined that normal reproduction can be performed, the signal recording is continued as it is, but when it is determined that normal reproduction cannot be performed, the recording area where the abnormality has occurred is determined. Is invalidated.

[0012]

According to the disk recording / reproducing apparatus of the present invention, when the ambient temperature of the optical head suddenly changes, or when a large impact force is applied to the optical head, an abnormality occurs in signal recording. Since the file management information for the recording area where the abnormality has occurred is invalidated, the problem caused by reproducing the signal from the abnormal recording area during the signal reproduction can be prevented beforehand.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention applied to a disk recording / reproducing apparatus using a magneto-optical disk as a recording medium will be specifically described below with reference to the drawings. As shown in FIG. 1, a disk recording / reproducing apparatus according to the present invention includes a spindle motor (2) for rotating and driving a magneto-optical disk (1).
An optical head (4), a reproduced signal amplifier circuit (5), a reproduced signal detection circuit (7), and an error correction circuit (11) are provided. When reproducing a signal, the optical head (4) is driven by a laser drive circuit (15). Then, the magneto-optical disk (1) is irradiated with a laser beam.
On the other hand, the signal recording system includes a magnetic head drive circuit (14) and a magnetic head (3). At the time of signal recording, the laser drive circuit (15) and the optical head (4) are mounted on the magneto-optical disk.
It operates to locally heat (1). Further, as a control system, a servo circuit (6), an external synchronization signal generation circuit (8),
System controller (10), memory (9), delay circuit (1
2) and a timing pulse generating circuit (13).
Further, a temperature sensor (16) for measuring an environmental temperature is attached to the optical head (4).

The optical head (4) irradiates the laser beam to the magneto-optical disk (1) and detects the reflected light as an optical signal and a magneto-optical signal. The reproduction signal amplification circuit (5) is an optical head
After amplifying the optical signal and magneto-optical signal obtained from (4),
A focus error signal and a tracking error signal included in the optical signal are supplied to a servo circuit (6). The reproduction signal amplification circuit (5) supplies an optical signal detected due to the discontinuous area formed at a constant interval in the groove of the magneto-optical disk (1) to the external synchronization signal generation circuit (8). At the same time, the magneto-optical signal is supplied to the reproduction signal detection circuit (7).

The external synchronizing signal generation circuit (8) generates an external synchronizing signal and supplies it to the servo circuit (6) and the delay circuit (12). The servo circuit (6) executes a focus servo and a tracking servo with respect to an actuator (not shown) mounted on the optical head (4) based on the focus error signal and the tracking error signal, and based on an external synchronization signal. The rotation of the spindle motor (2) is controlled.

The reproduction signal detection circuit (7) supplies the detected reproduction signal to the error correction circuit (11), and the error correction circuit (11)
Demodulates the reproduced signal, detects an error in the reproduced data obtained thereby, corrects the error, and outputs the corrected reproduced data to the subsequent circuit. The delay circuit (12) generates a synchronization signal in which the phase of the external synchronization signal is delayed by a predetermined time, and outputs the synchronization signal to the timing pulse generation circuit (13). When recording a signal, the timing pulse generation circuit (13) uses the recording data modulated by a predetermined method and a delay circuit.
Receiving the synchronization signal input from (12), the magneto-optical disk
Generate a pulse signal for applying an alternating magnetic field to (1),
A pulse signal (write clock) for irradiating the magneto-optical disk (1) with pulse light is generated and supplied to the laser drive circuit (15). At the time of signal reproduction, the reproduction signal detection circuit (7)
The reproduction analog signal is converted into a digital signal based on the synchronization signal (read clock) from the delay circuit (12).

The magnetic head drive circuit (14) generates a drive signal for the magnetic head (3) based on the pulse signal from the timing pulse generation circuit (13). Magnetic head (3)
Applies an alternating magnetic field to the magneto-optical disk (1) based on a drive signal from the magnetic head drive circuit (14). The laser drive circuit (15) drives a semiconductor laser (not shown) provided in the optical head (4) based on a pulse signal from the timing pulse generation circuit (13). The optical head (4) generates a laser beam based on a drive signal from the laser drive circuit (15) and irradiates the magneto-optical disk (1).

The system controller (10) controls the operation of the delay circuit (12) based on the external synchronization signal obtained from the external synchronization signal generation circuit (8). Further, the system controller (10) calculates a bit error rate based on the error correction information obtained from the error correction circuit (11), and controls the operation of the laser drive circuit (15) according to the result. The laser drive circuit (15) adjusts the power of the laser light emitted from the optical head (4) at the time of signal reproduction to an optimum value according to the laser power control signal Cp supplied from the system controller (10).

Further, the system controller (10) determines whether or not there is a possibility that the signal was not properly recorded based on the temperature data obtained from the temperature sensor (16) during the signal recording. If there is a possibility, the signal is actually reproduced, and it is determined whether or not the signal can be normally reproduced. As a result, when it is determined that the signal can be reproduced normally, the signal recording is continued as it is, but when it is determined that the signal cannot be reproduced normally, an abnormality occurs. Invalidates the file management information corresponding to the recording area.

FIGS. 2 and 3 show specific procedures executed by the system controller 10 in the process of signal recording. First, a recording operation is started in step S1, and then, in step S2, the last recorded physical address during the recording operation is stored in the memory as ADlast.
Update Dlast. Next, in step S3, it is determined whether or not the recording operation is to be terminated. If the user performs an operation to terminate the recording operation, the process proceeds to step S12 in FIG.
Then, the last physical address is stored in the memory as ADok in step S13.
As ok, the file management information is recorded / updated, and the recording operation ends.

On the other hand, when it is determined NO in step S3 of FIG.
Based on the temperature data obtained from (16), it is detected whether there is a possibility that the signal recording has not been performed normally (trouble). For example, based on the environmental temperature at the time when the optimization of the laser power is performed, when a subsequent temperature change exceeds a threshold value (for example, 10 ° C.), this is detected as a trouble.

If the determination in step S4 is NO, the process returns to step S2, where the last physical address ADlast
Is repeated. Thereafter, if a large temperature change occurs for some reason, and the answer is YES in step S4, the process proceeds to step S5 to interrupt the recording operation and store the physical address ADng at this time in the memory.

Subsequently, in step S6, the address AD
The reproduction of the recording area from last to ADng is executed, and in step S7, it is determined whether or not the reproduction data is normal. For example, when the error rate of the reproduction data exceeds a threshold, it is determined that the reproduction data is not normal. If it is determined in step S7 that the reproduction data is normal,
After restarting the recording operation from the address (ADng + 1) in step S8, the process returns to step S2 to repeat the storage / update of the last physical address ADlast. On the other hand, step S7
When it is determined that the reproduction data is abnormal at the
In step S9, the final physical address of the normally reproduced data is stored in the memory as ADok.

Next, in step S10, it is determined whether or not to continue the recording operation. For example, in the case of a video signal,
If the abnormal reproduction data that cannot be corrected is contained within one screen (one field), it is determined that the recording operation is to be continued, and if the data spans multiple screens, it is determined that the recording operation is not to be continued. . If the determination is YES in step S10, the process proceeds to step S11, where the physical address of the recording start is set to (ADok + 1), and the next recording data is waited. When the next recording data arrives, FIG.
The process proceeds to step S1 to start the recording operation. On the other hand, the recording operation is not continued in step S10 of FIG.
When the determination is (No), the process proceeds to step S13,
The file management information is recorded / updated with the final physical address as ADok, and the recording operation ends.

According to the above procedure, new data is overwritten and recorded from the physical address (ADok + 1) where abnormal data is recorded, and the physical addresses (ADok + 1) to AD
The file management information on the abnormal data recorded in the ng recording area is deleted. Therefore, at the time of signal recording, for example, recording data for one screen containing abnormal data is discarded, but at the time of signal reproduction, normal recording is performed based on valid file management information recorded on the disc. Only data is reproduced, and a problem caused by abnormal reproduction of recorded data is prevented beforehand. It should be noted that the reproduced data that is lost due to the truncation of the recorded data is only one screen, so that the reproduced video is not greatly disturbed and there is no possibility that the system will fail.

[Brief description of the drawings]

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

FIG. 2 is a flowchart showing a first half of a procedure at the time of signal recording in the disc recording / reproducing apparatus.

FIG. 3 is a flowchart showing a latter half of the procedure.

FIG. 4 is an enlarged perspective view showing lands and grooves formed on the magneto-optical disk.

FIG. 5 is a graph showing a relationship between read power (write power) and a bit error rate.

[Description of Signs] (1) Magneto-optical disk (3) Magnetic head (4) Optical head (16) Temperature sensor (7) Reproduction signal detection circuit (9) Memory (10) System controller (11) Error correction circuit (15 ) Laser drive circuit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5D090 AA01 CC01 CC05 CC16 CC18 EE01 FF26 JJ01 JJ07 JJ09 LL09

Claims (5)

[Claims] 1. A disk recording / reproducing apparatus for irradiating a laser beam to a disk from an optical head to record a signal on the disk or reproducing a signal from the disk, controlling a signal recording operation and a reproduction operation. Means for generating file management information including the address of a recording signal at the time of signal recording, and recording the information on a disc; detecting means for detecting an environmental condition that may affect the signal recording operation; When the environmental conditions exceed a predetermined threshold in the process of
A signal is reproduced from a recording area including the address of the recording signal at that time, and a judging means for judging whether or not normal reproduction can be performed. When it is judged that normal reproduction cannot be performed,
A disk recording / reproducing apparatus comprising: invalidation means for invalidating file management information on a recording area in which an abnormality has occurred. 2. The disk recording / reproducing apparatus according to claim 1, wherein the detecting means detects a change amount of an ambient temperature of the optical head as an environmental condition. 3. The disk recording / reproducing apparatus according to claim 1, wherein the detecting means detects a magnitude of an impact force on the optical head as an environmental condition. 4. The disk recording / reproducing apparatus according to claim 1, wherein the control means records a new signal by overwriting in a recording area where an abnormality has occurred. 5. The disc recording / reproducing apparatus according to claim 1, wherein the judging means judges that an error has occurred in the reproduced signal when the error cannot be corrected.