Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
2000-01-12
2004-06-15
Tran, Thang V. (Department: 2652)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
C369S275300, C369S030100, C369S047540, C369S053290, C369S059250
Reexamination Certificate
active
06751176
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an optical disc, its recording method, its recording device, its reproducing method, and its reproducing device. More specifically, it relates to an optical disc having a recognition mark area behind a recorded area, its recording method, its recording device, its reproducing method, and its reproducing device.
BACKGROUND ART
An optical disc is a high-density information recording medium in which information is recorded by using a semiconductor laser and is reproduced by using the difference in the reflectance of light beams between a recorded part and an unrecorded part.
The optical disc is provided with one or a plurality of “recorded area(s)” in which a predetermined information signal is written. “An unrecorded area” in which a new information signal can be written is provided outside the recorded area. In particular, in order to reproduce an optical disc on which recording has been performed several times, it is necessary to know the number of the recorded areas of the disc. In other words, it is necessary to detect “the last recorded area” of the disc to be reproduced. In this way, in order to detect the last recorded area of the disc to be reproduced, it is necessary to access the recorded areas sequentially from the first recorded area by moving the optical head repeatedly. However, it is impossible to know whether a succeeding recorded area exists or not before the optical head is moved to the position, and when the optical head is moved to an unrecorded area, servo control cannot be performed, thus bringing about an abnormal state.
Therefore, in a reproducing method for an optical disc described in Published Unexamined (Kokai) Japanese Patent Application No. Hei 6-349252, an address of a lead-out area is readded at a lead-in area provided in the first position of the recorded area, and then this lead-out area is accessed. Next, an optical head is moved to the succeeding recorded area by repeating one or more jump of one track or a plurality of tracks in the direction to the outer circumference. When it is decided that the optical head reaches the unrecorded area, the optical head is returned toward the inner circumference side without turning on the tracking servo. According to this method, an abnormal state due to the disability of the servo control is prevented.
However, in the reproducing method for the optical disc described in the above-mentioned publication, the optical head cannot be prevented from reaching the unrecorded area in detecting “the last recorded area.” Therefore, it becomes necessary to perform an operation of returning the optical head toward the inner circumference side without turning on the tracking servo. Thus, “the last recorded area” cannot be detected efficiently.
Recently, a technique is suggested, in which a recognition mark area for recognizing whether the succeeding area is an unrecorded area or not is provided just behind the last data in the recorded area, and the state of the recognition mark area is detected by the behavior when the recognition mark area is accessed, thereby determining whether the area behind the recognition mark area is an unrecorded area or a recorded area (whether the recorded area is the last recorded area or not). In this technique, when the recognition mark area cannot normally be accessed, the succeeding area is determinined to be the unrecorded area. In this case, when the recognition mark area is accessed, first, the lead-in data at the head of the recorded area is accessed so as to obtain the address of the lead-out area, and then the address of the recognition mark area existing in the vicinity of the head of the lead-out area is accessed. When a new information signal is written in the unrecorded area, a reproducible recording mark that does not cause a data error is recorded in the recognition mark area, and at the same time a new recognition mark area is provided behind the area in which the new information signal is written (the new recorded area).
However, in the above-mentioned marking method, when the recognition mark area is provided just behind the last data in the recorded area, if an access error exists when the last data in the recorded area is accessed, the optical head wrongly jumps to the recognition mark area, which may lead to an unstable access operation. Furthermore, when the recognition mark area is provided just before the unrecorded area, the optical head jumps to the unrecorded area at the time of accessing the recognition mark area, thus bringing about an abnormal state due to the disability of the servo control. In addition, if a succeeding recorded area exists, when the first data in the succeeding recorded area is accessed, the optical head jumps to the recognition mark area, thus bringing about an unstable access operation.
DISCLOSURE OF INVENTION
The present invention is intended to overcome the above-mentioned problem according to the prior art. It is therefore an object of the present invention to provide an optical disc in which a last data in the recorded area is stably accessed, a recognition mark area can be accessed without bringing about an abnormal state, and the first data in a succeeding recorded area, if it exists, is stably accessed, its recording method, its recording device, its reproducing method and its reproducing device.
In order to achieve the above-mentioned object, a first configuration of the optical disc according to the present invention has a concentric or spiral information track, and, behind a recorded area in which information is recorded on the information track, a first buffer area having a width wider than an access error when the last data in the recorded area is accessed, and a recognition mark area are recorded. According to the first configuration of the optical disc, since the optical head can be prevented from jumping to the recognition mark area when the reproducing device accesses the last data in the recorded area, a stable access operation can be realized in any one of states selected from a state in which no recording mark exists in the recognition mark area and a state in which a non-reproducible recording mark is formed.
Furthermore, it is preferable in the above-mentioned first configuration of the optical disc according to the present invention that the width of the first buffer area is 20 tracks or more and 100 tracks or less. It is preferable that the first buffer area be as small as possible since it greatly consumes the recorded area of the optical disc, however, in the access of the reproducing device for the optical disc, an error corresponding to several tens of tracks generally occurs.
Furthermore, it is preferable in the above-mentioned first configuration of the optical disc according to the present invention that the width of the recognition mark area is 2 tracks or less. In order to prevent the tracking from easily being off and to perform the detection and relead-in promptly if the tracking-off occurs, the width of the recognition mark area is desired to be as short as possible. However, in order to record a reproducible recording mark on the recognition mark area that does not bring about a data error, it is necessary to record the reproducible recording mark using the block length for correcting error as a unit. Therefore, the width of the recognition mark area is required to be the length corresponding to the block length for correcting error. Moreover, it is desirable that the width of the recognition mark area is twice or more the block length for correcting error in order to avoid an incorrect recognition even if a data error occurs at the time of reproducing information. For example, in the case of a DVD disc, twice the block length for correcting error is 0.5 tracks to 1.1 tracks. Thus, it is possible to record the reproducible recording mark when the width of the recognition mark area is 2 tracks or less. Therefore, it is preferable that the width of the recognition mark area is 2 tracks or less.
Furthermore, it is preferable in the above-mentioned first con
Fujimoto Mitsuteru
Kanda Yoshihiro
Moriya Mitsurou
Battaglia Michael
Matsushita Electric - Industrial Co., Ltd.
Merchant & Gould P.C.
Tran Thang V.
LandOfFree
Optical disk with buffer area and recording and reproducing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Optical disk with buffer area and recording and reproducing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical disk with buffer area and recording and reproducing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3351817