JP2001236667A - Optical information recording/reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical information recording/reproducing device for reducing the probability for performing recording/erasing operation on separated track while detecting a wheel-drop phenomenon in a PID part. SOLUTION: This device compares a tracking error signal (TE signal) with a reference signal falsely generated by holding a response of the TE signal in the normally reproducible PID part, and detects that the change of the TE signal of a comparison level or above is continued for a reference time, and stops the recording/erasing operation to a disk 101 in the case of detecting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical information recording / reproducing apparatus capable of recording / erasing information on / from an information recording medium by irradiating light.

[0002]

2. Description of the Related Art Conventionally, an information recording medium in which information is recorded on a disc-shaped information recording medium by utilizing a phase change reversibly changed to a crystalline state and an amorphous state having different reflectances from each other has been developed. Various types of optical information recording / reproducing devices for optically reading and reproducing the information are known and have already been put to practical use. Particularly, in recent years, as an information recording medium capable of recording a large amount of information by increasing its information recording density, for example, a DVD-RAM (Digital Versatil
A so-called e-Disc-Random Access Memory (Disc) disc has been proposed and attracted attention, and an optical information recording / reproducing apparatus for recording and reproducing information on a DVD-RAM disc has already been marketed.

A point to be noted when recording or erasing information on an information recording medium on which such information can be recorded is a phenomenon called derailing. The detachment is formed on the recording surface of the disk due to an abnormality caused by an external factor (earthquake, impact to the device) such as a vibration of the device or an internal factor inherent to the device (scratch, dirt, defect on the disk surface). This refers to a phenomenon in which a light spot deviates from a track to be scanned.

If a derailment occurs while recording information, information on another track will be erased by mistake. Therefore, it is monitored whether or not a derailment has occurred.
If the recording or erasing operation is being performed at that time, it is necessary to stop the operation. In a conventional optical information recording / reproducing apparatus, the derailing phenomenon is detected by a configuration as shown in FIG. Hereinafter, a conventional optical information recording / reproducing apparatus capable of detecting a wheel-release phenomenon will be described with reference to FIG. This figure is a block diagram showing a configuration necessary for detecting a de-wheeling phenomenon in the optical information recording / reproducing device, and the description of other components of the optical information recording / reproducing device is omitted.

The disk 101 is rotated by the spindle 102, and the disk 101 is irradiated with laser light from the optical head 103 to form a light spot on the recording surface of the disk 101. Then, the optical head 103 detects the reflected light of the laser light applied to the disk 101, and generates various signals according to the level of the reflected light. Among the generated signals, it is determined whether or not a signal level (voltage) of a signal indicating a variation amount with respect to the track center of the disk, which is called a tracking error signal (TE signal) used for so-called tracking control, exceeds a comparison level. Comparator 1
In step 04, a signal is output that is high level when the signal level exceeds the comparison level, and is low level when the signal level is not higher than the comparison level.

At this time, in the figure, the comparator 104 simply shows a comparator of one level, but actually forms a window comparator, and the comparison reference level 110 is compared in the positive direction and the negative direction.

In the time measuring device 105, the comparator 10
The time during which the signal output from 4 is at the high level is measured. If this output time exceeds the reference time,
A signal is output to the OR (logical sum) circuit 109 because the light spot may have accidentally departed to another track or may have already departed.

On the other hand, from the TE signal, the P
ID part (physical location information on disk Physical ID
Pits formed beforehand in the area where the pits are formed), the PID demodulator 10
In step 6, the TE signal is demodulated and information is read. Since the pit information of the PID section includes track position information, it is possible to know which track the light spot is scanning. Further, the order of the track position information is stored in the PID register 107 before recording and reproducing information. Then, the comparator 108 reads the PI from the disk next from the PID register 107.
The position information of the D section is received, and this position information is compared with the position information of the PID section actually read by the PID demodulator 106. If the comparison results do not match, it is known that the light spot has erroneously deviated to another track, so a signal is output to the OR circuit 109.

The OR circuit 109 is connected to the time measuring device 1
05 or a signal from the comparator 108, a recording / erasing stop signal is output to stop the information recording / erasing operation by the optical information recording / reproducing apparatus.

[0010]

In the above-described conventional optical information recording / reproducing apparatus, during recording / erasing, a P
Since the ID section cannot detect the current state of derailing due to an abnormality in the TE signal, the PID can be demodulated at the head of the PID part, and when derailment occurs in the latter part of the PID part, detection of the occurrence of derailing is detected. And the stop processing of recording or erasing may be delayed.

The present invention solves such a problem and provides a PID
It is an object of the present invention to provide an optical information recording / reproducing apparatus that reduces the possibility of performing a recording / erasing operation on another track while improving a detection delay of a derailing phenomenon in a section.

[0012]

In order to achieve the above-mentioned object, according to the present invention, a method of recording information on a disk while controlling the amount of change in the radial position of a light spot with respect to the center of a track.
In an optical information recording / reproducing apparatus for erasing, a means for holding the amount of change in the PID unit, an adding means for adding the held amount of change to a specified amount, and a means for comparing the addition result with the amount of change An optical information recording / reproducing apparatus comprising: means for measuring a time when the amount of change exceeds the addition result; and means for stopping recording / erasing operation of information when the time exceeds a reference time. .

[0013]

Embodiments of the present invention will be described below.

To facilitate understanding of the present invention, the structure of the disk and the phenomenon of derailing will first be described. FIG.
1 is a partially enlarged view showing an example of a disc 101 on which information is recorded / erased by an optical information recording / reproducing apparatus to which the present invention has been applied.

The disk 101 has a groove 20
Information can be recorded / erased on both 1 (G) and the land 202 (L). The groove part 201 and the land part 202
It is formed alternately for each round of the disk, and is formed along the track 203. PID portions 204 are provided at regular intervals between the groove portions 201 and the land portions 202, and pits 205 are formed in the PID portions 204. The pit 205 is offset in the inner circumferential direction and the outer circumferential direction with respect to the track 203, and is formed at substantially the same depth as the groove portion 201. Although shown in a simplified manner in the figure, about 100 small pits are actually formed in each case.

When the light spot is scanned along the track 203 of the groove 201 and when the light spot is scanned along the track of the land 202, the pit 20
Changes the detection level.

In the example shown in FIG.
In this case, the pit 205 offset to the outer peripheral side is scanned, and then the pit 205 offset to the inner peripheral side is scanned. On the other hand, the land 20
When the second track is scanned, the pit 205 offset to the inner peripheral side is scanned, and then the pit 205 offset to the outer peripheral side is scanned.

FIG. 2 shows the locus 20 of the light spot.
8, 209 are schematically shown. When information is recorded / erased by scanning a track normally, the light spot advances along a locus 208 shown by a dotted line to record / erase information. However, external factors such as equipment vibration (earthquake,
Abnormality occurred due to an external impact, etc.) or internal factors inherent to the device (scratch, dirt, defects on the disk surface), causing the irradiation position in the radial direction of the light spot to fluctuate and causing derailing. In this case, the light spot deviates from the locus 208 to be scanned, for example, the locus 209 indicated by a solid line.
It will proceed like. When the track advances along the locus 209, information on another track may be erroneously recorded / erased.

In the optical information recording / reproducing apparatus to which the present invention described below is applied, the trajectory of the light spot detects a derailing phenomenon like the trajectory 209, and if detected, the recording / erasing operation is stopped. Can be.

FIG. 1 is an example of a block diagram of an optical information recording / reproducing apparatus to which the present invention is applied. This figure is a block diagram showing a configuration of the optical information recording / reproducing apparatus related to detection of a derailing phenomenon, and a description of other components of the optical information recording / reproducing apparatus is omitted. It is assumed that the operation of each block in the figure is controlled by control means (not shown).

The disk 101 is rotated by the spindle 102, and the disk 101 is irradiated with laser light from the optical head 103 to form a light spot on the recording surface of the disk 101. Then, the optical head 103 detects the reflected light of the laser light applied to the disk 101, and generates various signals according to the level of the reflected light. Of the generated signals, the signal level of a signal indicating a radial variation with respect to the track center of the disk, called a tracking error signal (TE signal), is simultaneously output.

At this time, TE in PID1, 2 (211)
The signal level is held by the S / H 121, and PID3, 4
The TE signal level at (212) is held by the S / H (sample and hold circuit) 122. S / H121 and S
The output of / H122 is held by S / H123 and S / H124 when the PID can be reproduced.

The switch 126 is open in the data section 221 but is closed in the PID section 204 and the LPF 127
Output of S / H123 or S / H124 is switch 1
The input is switched by 25.

The output of LPF 127 is added to detection level 110 by adder 128, and LPF 127 is output by comparator 104.
(High-frequency cutoff circuit) 110 is compared with the output. Actually, the comparator 104 is a window comparator, and the LPF 11
The output of 0 is compared on both the positive side and the negative side of the output of the adder 128, and the time measuring device 105 detects the time when the output of the LPF 110 exceeds the output of the adder 128, and the time when the output exceeds the reference time. In this case, a signal is output to the OR circuit 109 because the light spot may have accidentally derailed to another track.

The OR circuit 109 is connected to the time measuring device 1
When a signal is received from 05, a recording / erasing stop signal is output to stop the information recording / erasing operation.

Here, the relationship between the structure of the disk 101 and the signal level of the TE signal obtained by detecting the return light from the disk 101 and the comparison level will be described.
FIG. 3 is a diagram showing the relationship between the structure of the disk 101 and the TE signal 401. In the figure, the cross section of the disk 101 is shown in the upper part, and the radial position of this disk 101 and T
The relationship with the value (voltage) of the E signal is shown.

The TE signal 401 corresponds to the track 2 as described above.
This signal indicates the amount of fluctuation in the radial direction with respect to 03, and takes a reference level (normally 0 voltage) when located at the center of the track. The level (voltage) becomes higher or lower in accordance with the deviation (fluctuation amount) from the track center, and the groove (G) 201 and the land (L) 202
When the light spot is located at the boundary between the two, the value takes the maximum or minimum level (voltage).

The so-called tracking control is performed by monitoring the change in the TE signal and controlling the position of the light spot so that the level of the TE signal becomes the reference level. Since the information is recorded and erased while performing the tracking control even when the information is recorded and erased, the light spot normally has a locus 20 in FIG.
Information is recorded / erased by drawing a normal trajectory as shown in FIG.

However, if there is a fluctuation that cannot be controlled by the tracking control, the wheel may be derailed, and the recording / erasing of information may be performed by drawing an abnormal trajectory such as the trajectory 209 in FIG. will have to go. In the prior art described above,
The TE signal and the reference value of one system are configured to detect the possibility of derailing using a comparator. However, if this detection is attempted with the reference value of one system, the PID portion having no track groove is used. Cannot obtain a TE signal, and therefore cannot solve the problem that the derailing phenomenon cannot be detected in the PID section. Therefore, in the present embodiment, T in the PID section
This problem is solved by providing a retainer for outputting the E signal.

The advantages of the present invention will be described with reference to FIGS.

FIG. 4 shows a case where the light spot is operated on the trajectory 208 without derailing. In the output 401 from the optical head, a modulation according to the pit is obtained in the PID unit 204, and a signal of a constant frequency due to the groove shape slightly oscillated in the radial direction (not shown) is superimposed in the data unit 221. I have. The output 402 from the LPF 110 is S /
S / H control 1 in H121 and S / H122 (403)
And the level is held in accordance with the S / H control 2 (404). PID1, 2 (211) and PID3, 4 (21
If 2) is reproducible and has proper contents, S / H control 3 (405) and S / H control 4 (406) are output, respectively, and the outputs of S / H 121 and S / H 122 H123 and S / H124.

Although not explicitly shown in FIG. 1, a control device for generating control signals for S / H and switches is provided. The groove portion 201 and the land portion 202 of the disk 101
PID1, 2 and P
Although the polarities of the IDs 3 and 4 are switched, the switch control 2 (408) that controls the switch 125 outputs in consideration of the switching.

PID according to switch control 1 (407)
The output from the switch 126 closed by the unit 204 is L
It is blunted by the PF 127, added to the detection voltage 110 by the adder 128, and input to the comparator 104 as a comparison reference value. The characteristics of the LPF 127 match the response of the LPF 110. Although it is simply described in FIG. 1,
The comparator 104 is a window comparator, and monitors that the output of the LPF 110 does not exceed the range of the reference potential obtained by adding the detection voltage 110 to the positive side and the negative side of the LPF output 2 (410).

FIG. 5 shows that derailing occurs in the PID unit 204,
Each signal output and the output of the present derailing detection device resulting from scanning as shown by a locus 209 are shown. PID1, 2 and PID3, 4 become unreproducible due to the derailment, S
/ H control 3 and S / H control 4 are not output. S / H1
The adder output 411 is generated using the levels held in the S / H 124 and the S / H 124, respectively. At this time LPF11
Compared with the output 502 from 0, the comparator output 512 is obtained. If the time at which the derailing is detected in the time measurement 105 exceeds the reference time, a recording / erasing stop signal is output through the logical sum 109, and if recording or erasing processing is being performed, the processing is stopped.

FIG. 6 shows a conventional wheel removal detection circuit. LPF
The output of the comparator 110 is a window comparator.
4, the occurrence of derailing is detected by comparing with the detection voltage 110, but the PID unit 204 needs to stop the detection operation because it malfunctions. Simultaneously, the information on the PID section obtained by the demodulator 106 is compared with the expected value stored in the PID register 107 by the comparator 108 to detect the occurrence of wheel derailment. It has a defect that it cannot detect derailment.

Accordingly, if the detection of the derailing is delayed most by the conventional derailing detection circuit, it is a symptom of the derailing of the locus 209 in FIG. 5, and the information at the head of the PID unit 204 can be reproduced as an appropriate value. In this case, the recording or erasing process is executed without any problem, and thereafter, the scanning position is shifted from the appropriate track center 208 in the PID unit 204 and the recording is performed to the groove unit 201 two tracks away.

By simulating the TE signal generated in the PID section and using it as a reference potential for derailing detection, the pit contents of the PID section can be reproduced without verifying the pit contents of the PID section. The occurrence of wheel loss can be detected, and the detection of wheel loss does not depend on the defect in the PID portion and the reproduction ability in the PID portion.

In FIG. 4, the comparison levels 402 and 403 show only one side + potential. However, even in the case of the negative potential having the same absolute value, the comparison with the TE signal is similarly performed to detect the derailment.

Returning to the description of the optical information recording / reproducing apparatus shown in FIG. While the amount of change with respect to the track 203 can be grasped from the signal waveform of the TE signal 401, the information of the pit 205 formed in the PID section 204 of the disk 101 can be read from the TE signal 401. So PI
The D demodulator 106 demodulates the TE signal and reads information. Since the pit information of the PID section includes track position information, the optical information recording / reproducing apparatus
Each time the light spot passes, it is possible to know which track the light spot is scanning. In addition, information indicating the position information of the track to be recorded or erased is stored in the PID register 107 before recording or erasing the information.
Therefore, the comparator 108 determines the position information of the PID part to be reproduced, which is output from the PID register 107, and the PI.
A comparison is made with the position information of the PID section read by the D demodulator 106. If the comparison results do not match, it is known that the light spot has erroneously deviated to another track, so a signal is output to the OR circuit 109.

The OR circuit 109 is connected to the comparator 108
When a signal is output from the device, a recording / erasing stop signal is output, and information recording / reproduction by the optical information recording / reproducing device is performed.
Stop the erase operation.

According to the embodiment in which the derailing is detected by the comparator 108 in addition to the derailing detection by the comparator and the time measuring device described above, in addition to the above-described effects, the erroneous recording / erroneous erasing due to the derailing is eliminated. The light spot can be suppressed within the range of the groove or land where the light spot has shifted when the ring occurs. By reading the position information of the PID section, it can be seen that the track has been moved to another track. Therefore, information recording and
The erasing operation is not continued, and erroneous recording and erroneous erasure due to derailing can be suppressed within the range of the groove or land where the light spot has moved when the derailing occurred.

Further, in FIG. 2, a radial boundary between the groove portion 201 and the land portion 202 of the disk 101 is shown by a straight line, and the boundary is wobbled (wobbled) at a constant period in the disk. Some discs are burning. Hereinafter, description will be made assuming that this boundary of the disk 101 is wobbled.

The essence of the present invention is that a reference TE signal is generated in a pseudo manner in a PID portion having no groove, and a change in a TE signal which is higher than a comparison level from a detection level generated from the pseudo TE signal continues for a reference time. An optical information recording / reproducing apparatus which stops a recording / erasing operation on a disk when the optical information recording / reproducing operation is detected.

[0044]

According to the present invention, it is possible to provide an optical information recording / reproducing apparatus which reduces the possibility of erroneous detection of the derailing phenomenon and the possibility of erroneously performing a recording / erasing operation on another track.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of an optical information recording / reproducing apparatus to which the present invention has been applied.

FIG. 2 is a partially enlarged view showing an example of a disc 101 on which information is recorded / erased by an optical information recording / reproducing apparatus to which the present invention is applied.

FIG. 3 is a diagram showing the relationship between the structure of a disk 101 and a TE signal 401.

FIG. 4 is a diagram illustrating a relationship between a trajectory of a light spot in a normal PID unit, a TE signal input to a comparator, an output signal of a comparator (input signal to a time measuring device), and an output signal of the time measuring device. .

FIG. 5 shows the locus of the light spot, the TE signal input to the comparator, the output signal of the comparator (input signal to the time measuring device), and the output signal of the time measuring device when derailing occurs in the PID section. It is a figure showing a relation.

FIG. 6 is a block diagram of a conventional optical information recording / reproducing apparatus capable of detecting a wheel drop phenomenon.

[Explanation of symbols]

101: disk, 102: spindle, 103: optical head, 104, 110: comparator, 105, 111
... Time measuring instrument, 106 ... PID demodulator, 107 ... PID
Register, 108... Comparator, 109... OR circuit.

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Claims (4)

[Claims] 1. A method for recording information on a disk while controlling the amount of change in the radial position of a light spot with respect to the center of a track.
In an optical information recording / reproducing apparatus in which reproduction and erasure are performed and identification information is recorded in advance on the disc, a time during which the fluctuation amount exceeds a specified fluctuation amount is determined by comparing the fluctuation amount with a reference level. An optical information recording / reproducing apparatus, comprising: means for stopping the recording / erasing operation of information when exceeding, and means for correcting the comparison level at a position on the disc where the identification information is recorded. 2. The optical information recording / reproducing apparatus according to claim 1, further comprising a switch for changing the level for correcting the comparison level. 3. The optical information recording / reproducing apparatus according to claim 1, wherein the correction level is switched for each of the correction levels according to the position of the identification information. 4. The optical information recording / reproducing apparatus according to claim 1, further comprising means for holding a level of said identification unit.