Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
1998-07-23
2001-03-27
Hindi, Nabil (Department: 2651)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
C369S053370
Reexamination Certificate
active
06208599
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an optical disk apparatus and, more particularly, to an optical disk apparatus capable of recording data on an optical disk medium using a plurality of laser beams.
In a conventional optical disk apparatus, data are recorded on an optical disk medium by irradiating the optical disk medium with a beam. In this case, data are recorded on the optical disk medium using changes in shape of those portions of the optical disk medium which are heated by irradiation of the optical disk medium with a beam, the direction of magnetic fields aligned under the influence of an external magnetic field when a high temperature decreases to room temperature, and changes in crystalline state caused by the temperature difference between a high temperature and room temperature.
In an optical disk apparatus of this type, when the servo becomes unstable during recording/erase of data on/from an optical disk medium, the recording/erase immediately stops in order to protect user data near portions where data are to be recorded/erased. Also, when an abnormal portion is detected on an optical disk medium, recording/erase immediately stops.
The above optical disk apparatus is constructed by a recording head
319
and an erase head
320
, as shown in FIG.
5
. The recording head
319
is constituted by a semiconductor laser
301
, a laser driver
302
, a protective circuit
303
, a recording data generator
304
, a photodetector
305
, a medium reflection signal generator
306
, a recording abnormality detector
307
, a reproducing circuit
308
, and an abnormal sector memory
309
.
The erase head
320
is constituted by a semiconductor laser
310
, a laser driver
311
, a protective circuit
312
, an erase data generator
313
, a photodetector
314
, a medium reflection signal generator
315
, an erase abnormality detector
316
, a reproducing circuit
317
, and an abnormal sector memory
318
.
When data are simultaneously recorded and erased with a plurality of heads, they are substantially simultaneously recorded by the recording head
319
and erased by the erase head
320
at the same portion of a recording medium
321
on the same track.
A signal obtained from the recording data generator
304
is transmitted to the laser driver
302
via the protective circuit
303
. On the basis of the recording signal transmitted via the protective circuit
303
, the laser driver
302
records data on the recording medium
321
using the semiconductor laser
301
.
A signal obtained from the erase data generator
313
is transmitted to the laser driver
311
via the protective circuit
312
. On the basis of the erase signal transmitted via the protective circuit
312
, the laser driver
311
records erase data on the recording medium
321
using the semiconductor laser
310
to erase data from the recording medium
321
.
In recording, a signal obtained via the photodetector
305
is converted into a medium reflection signal by the medium reflection signal generator
306
. The medium reflection signal is transmitted to the recording abnormality detector
307
. The recording abnormality detector
307
detects based on the medium reflection signal whether focusing control and tracking control fall within normal ranges, and the medium is free from any defect.
A recording abnormality detection signal detected by the recording abnormality detector
307
is transmitted to the protective circuit
303
and the abnormal sector memory
309
, and in addition, to the protective circuit
312
and abnormal sector memory
318
of the erase head
320
. Upon reception of the recording abnormality detection signal, the protective circuit
303
immediately stops transmission of recording data to the laser driver
302
. In the abnormal sector memory
309
, a sector detected to have a recording abnormality is stored on the basis of signals obtained from the reproducing circuit
308
and the recording abnormality detector
307
.
In the erase head
320
, the protective circuit
312
immediately stops transmission of erase data to the laser driver
311
upon reception of the recording abnormality detection signal. In the abnormal sector memory
318
, a sector subjected to forcible stop due to the recording abnormality is stored on the basis of signals obtained from the reproducing circuit
317
and the recording abnormality detector
307
. The abnormal recording sector and the abnormal erase sector obtained from the abnormal sector memories
309
and
318
are subjected to recording and erase retries or swapping of recording data on other sectors.
In erase, a signal obtained via the photodetector
314
is converted into a medium reflection signal by the medium reflection signal generator
315
. The medium reflection signal is transmitted to the erase abnormality detector
316
. The recording abnormality detector
316
detects based on the medium reflection signal whether focusing control and tracking control fall within normal ranges, and the medium is free from any defect.
An erase abnormality detection signal detected by the erase abnormality detector
316
is transmitted to the protective circuit
312
and the abnormal sector memory
318
, and in addition, to the protective circuit
303
and abnormal sector memory
309
of the recording head
319
. Upon reception of the erase abnormality detection signal, the protective circuit
312
immediately stops transmission of erase data to the laser driver
311
. In the abnormal sector memory
318
, a sector detected to have an erase abnormality is stored on the basis of signals obtained from the reproducing circuit
317
and the erase abnormality detector
316
.
In the recording head
319
, the protective circuit
303
immediately stops transmission of recording data to the laser driver
302
upon reception of the erase abnormality detection signal. In the abnormal sector memory
309
, a sector subjected to forcible stop due to the erase abnormality is stored on the basis of signals obtained from the reproducing circuit
308
and the erase abnormality detector
316
. The abnormal recording sector and the abnormal erase sector obtained from the abnormal sector memories
309
and
318
are subjected to recording and erase retries or swapping of recording data on other sectors.
In the conventional optical disk apparatus described above, if the recording abnormality detector
307
or the erase abnormality detector
316
detects an abnormality, the other circuit (erase head
320
or recording head
319
) is also informed of this abnormality, and erase or recording in the other circuit is forcibly stopped.
For this reason, a sector, which may normally undergo recording or erase, is processed as an abnormal sector by an abnormal stop signal from one head. As a result, the recording and erase times of the optical disk apparatus are prolonged.
The above operation will be explained on the time axis shown in
FIGS. 2A
to
2
D,
2
G, and
2
H.
FIGS. 2A
to
2
D,
2
G, and
2
H show the case wherein the recording head
319
records data on recording sectors
200
“X, X+1, X+2, . . . ”, and the recording head
320
erases data from erase sectors
203
“Y, Y+1, Y+2, . . . ”, as shown in FIG.
2
D.
When a recording abnormality occurs in the recording sector
200
“X+1” (FIG.
2
A), and an abnormality signal
201
(
FIG. 2B
) is output upon detection of the recording abnormality, an abnormal recording stop signal
202
(
FIG. 2C
) is input to the protective circuit
303
to stop current recording. “X+1” is stored as an abnormal recording sector in the abnormal sector memory
309
.
At the same time, on the erase head
320
side, the abnormal recording stop signal
202
(
FIG. 2C
) input to the protective circuit
312
immediately stops current erase. “Y+1” is stored as an abnormal erase sector in the abnormal sector memory
318
. As for the erase sector, no recording abnormality occurs in the sector “Y+1”, but only the abnormal recording stop signal
202
(
FIG. 2C
) is input from the recording head
319
. Pro
Foley & Lardner
Hindi Nabil
NEC Corporation
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