Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
1998-07-10
2001-03-27
Hindi, Nabil (Department: 2753)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
C369S059160, C369S275300
Reexamination Certificate
active
06208600
ABSTRACT:
TECHNICAL FIELD
The invention relates to a method and a device for recording data in an optical memory card, and more particularly to a method and a device for recording data in an optical memory card, that records data so as to form at least one record pit between two data records in a recording region of the optical memory card in order to improve a function of judging between an unrecorded region and a recorded region of the optical memory card, thereby preventing double writing.
BACKGROUND ART
Generally, the optical memory card is a plastic card and can record and reproduce data in its recording region with a laser beam.
FIG. 7
shows a recording region
102
of an optical memory card
101
. As shown in its enlarged diagram, data recording tracks
103
for recording information and guide tracks
104
formed at given intervals required for tracking control for stabilizing a radiating position of the laser beams for recording and reproducing are alternately disposed on the recording region
102
.
The data recording tracks
103
and the guide tracks
104
have a different reflection ratio. Comparing the reflection ratio of these two, the data recording tracks
103
have a higher reflection ratio and the guide tracks
104
have a lower reflection ratio.
And, a record pit
105
is a portion having a low reflection ratio, which is formed in the data recording tracks
103
, with the laser beam to record information. The presence or not of the record pit
105
indicates information to be recorded.
FIG. 8
shows a logical data structure of the recording region
102
. On the recording region
102
, read-in
111
provided for an unillustrated optical memory card reader/writer to realize a bit synchronization at the time of recording or reproducing and an SYNC mark
112
for the unillustrated optical memory card reader/writer to realize a frame synchronization at the time of recording or reproducing have been recorded, in addition to a data recording region
110
where information is recorded.
The read-in
111
has the SYNC mark
112
recorded and record pits
105
formed at given intervals.
An optical memory card reader/writer (not shown) is provided with a synchronization signal generator (not shown), scans the optical memory card
101
at a scan rate so that a synchronization signal output from the synchronization signal generator agrees with a signal which rises for every one bit detected by scanning the read-in
111
, and keeps the same scan rate to make bit synchronization.
And, the SYNC mark
112
is formed of record pits
105
, which are arranged in a pattern not produced by modulation, and used when the unillustrated optical memory card reader/writer gets frame synchronization.
The frame is a bit separation to process a signal by a signal processing circuit in the unillustrated optical memory card reader/writer. The unillustrated optical memory card reader/writer is provided with a counter (not shown) for obtaining frame synchronization. The counter counts the synchronization signal, outputs a frame synchronization signal after counting up to the number of bits configuring one frame, and resets its counted number.
Since the SYNC mark
112
is recorded at the start end (or termination end) of the frame, the unillustrated optical memory card reader/writer scans the optical memory card
101
. And when the SYNC mark
112
is detected, the number indicated by the unillustrated counter for obtaining frame synchronization is reset, thereby assuring the acquisition of frame synchronization.
And, the data recording region
110
has the SYNC mark and n sectors
113
arranged as indicated by a data recording region
110
-
1
on each frame. The sector
113
is composed of a single or a plurality of bits.
FIG. 9
is a diagram showing an NRZI-RZ (nonreturn-to-zero change on 1-return to zero) modulation system for converting data, which is recorded in a conventionally used optical memory card, into the presence or not of a record pit.
The NRZI-RZ modulation system is a modulation system to produce a pulse at a polarity reversion position of an NRZI (nonreturn-to-zero change on 1) modulation system.
When data shown in FIG.
9
(
a
) is modulated, the NRZI modulation system reverses the polarity of a signal at the bit midpoint of data “1” as shown in FIG.
9
(
b
).
Accordingly, the NRZI-RZ modulation system generates a pulse at a polarity reversion position of FIG.
9
(
b
) as shown in FIG.
9
(
c
).
Data modulated by the NRZI-RZ modulation system is recorded by forming a record pit in the recording region of the optical memory card so as to correspond to the position of the pulse as shown in FIG.
9
(
d
).
As apparent from FIG.
9
(
a
) and FIG.
9
(
d
), the NRZI-RZ modulation system does not form a record pit on a part where data “0” is continuous.
However, before recording data on the optical memory card, the optical memory card reader/writer reproduces the optical memory card to detect the presence or not of a record pit. Thus, it judges between an unrecorded region and a recorded region of the optical memory card to prevent double writing on it. Therefore, if data to be recorded in the optical memory card has a portion where data “0” is continuous, a record pit is not formed on the optical memory card while data “0” is continuing. And, it becomes hard to judge between the unrecorded region and the recorded region, resulting in degrading a function of preventing double writing from being made by the optical memory card reader/writer.
SUMMARY OF THE INVENTION
Under the circumstances described above, it is an object of the invention to provide a method and a device for recording data in an optical memory card, which records data by a modulation system which forms a record pit even when data to be recorded has data “0” which continues, and changes the modulation system of a card recorded by the NRZI-RZ modulation system, to facilitate judgment between an unrecorded region and a recorded region of the optical memory card, thereby keeping a function of preventing double writing from being made by an optical memory card reader/writer.
In order to achieve the above object, the invention relates to a method of recording data in an optical memory card, in which data is recorded in such a manner as to form at least one record pit between two data records in a recording region of the optical memory card.
The recording region of the optical memory card comprises one-bit sectors in one frame, the data is modulated by an NRZI-RZ modulation system to record it in a sector for recording data and to reproduce a sector adjacent to the sector for recording data, and if the adjacent sector has been recorded and the record pit has not been formed in both the sector for recording data and the adjacent sector, a record pit is formed on a boundary between the sector for recording data and the adjacent sector.
The recording region of the optical memory card comprises plural-bit sectors in one frame, the data is modulated by an MFM-RZ modulation system to record it in a sector for recording data and to reproduce a sector adjacent to the sector for recording data, and if the adjacent sector has been recorded and the record pit has not been formed in both the sector for recording data and a record position in contact with a boundary of the adjacent sector, a record pit is formed on a boundary between the data-recorded sector and the adjacent sector.
The data is reproduced when the recording region of the optical memory card has data recorded by the NRZI-RZ modulation system, and the record pit is formed on a boundary of the record positions so as to modify to record by the MFM-RZ modulation system when the recording region of the optical memory card has continuous record positions where the record pit has not been recorded.
The invention also relates to a device for recording data in an optical memory card, which comprises means for recording data in such a manner as to form at least one record pit between two data records in a recording region of the optical memory card.
The recording region of the optical memory
Kimura Yasuyuki
Onodera Akira
Hindi Nabil
Hogan & Hartson LLP.
Kabushiki Kaisha Nippon Conlux
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