Dynamic information storage or retrieval – Storage medium structure – Optical track structure
Reexamination Certificate
2000-04-10
2001-11-13
Neyzari, Ali (Department: 2651)
Dynamic information storage or retrieval
Storage medium structure
Optical track structure
C369S275100
Reexamination Certificate
active
06317407
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical disk, and more particularly relates to a rewritable optical disk having a control data signal representing the type of the disk and the like recorded thereon.
2. Description of the Related Art
In recent years, various types of optical disks, for example, read-only types such as a CD and a CD-ROM and types which allow for data recording such as a data addition type and a rewritable type, have been widely used. Some of such optical disks of the read-only type, the data addition type, and the rewritable type are the same in appearance and the like, though they are different in type from each other.
Some of the optical disks are different from others in format type and parameters to be set at recording and/or reproduction. Information on the format type and information for setting parameters is therefore prerecorded as control data signals in a predetermined region of the disk, so that the control data signals are read with a drive for reproducing/recording data from/on the optical disk before various parameters are set for the drive.
A method for recording such control data signals on an optical disk will be described, using a “130 mm rewritable optical disk” as an example.
The “130 mm rewritable optical disk” has a format defined by JIS X6271. Two types of formats are defined by the standard: i.e., Format A where continuous grooves are formed spirally on a disk, and lands between adjacent grooves are used as tracks for recording signals; and Format B where marks for sampling are formed on a disk to allow for tracking control by a sample servo method. The two formats are common in the configuration of a control information track where the control data signals are recorded. That is, the control information track is specified to have a PEP region, an inner SFP region, and an outer SFP region for the two formats.
The PEP region is located on the innermost portion of the disk, where prerecord marks (also called embossed pits), obtained by modulating with low-frequency phase-modulated recording codes, are used. All the marks in the PEP region are arranged so as to be aligned in the radial direction of the disk. This arrangement is schematically shown in FIG.
3
A. Each prerecord mark and each space between adjacent prerecord marks are two channel bits long. One PEP bit cell has a length of 656±1 channel bits.
FIG. 4
shows forms of such PEP bit cells. The information of the PEP bit cell is represented by a phase-modulated recording code. A PEP bit cell where marks are formed in the first half thereof represents logical 0, while that where marks are formed in the second half thereof represents logical 1. A total of 561 to 567 PEP bit cells of the above forms per track are recorded on the disk.
The PEP region has a track format shown in
FIG. 5A
, which includes three sectors.
FIG. 5B
shows a sector format of each sector. The numbers shown in FIGS.
5
A and
5
B represent the numbers of PEP bit cells allocated to respective signals. A data region of the sector format where various control signals are recorded has a capacity of 18 bytes (144 PEP bit cells) (hereinafter, bytes are referred to as “B”). For example, a signal representing the format (Format A or B) to be used by the disk is recorded in byte 0. The details on other control signals to be recorded on the data region are specified in the aforementioned JIS standard. The description thereof is therefore omitted here.
When the PEP region with the above format is illuminated with light with an optical head or the like, light is focused on a signal recorded surface of the disk by focusing control. Since marks are aligned in the radial direction in the PEP area, signals can be reproduced without tracking control.
FIG. 3A
also shows an example of a beam track. The portion where no marks are formed serves as a mirror, producing a large amount of reflection light. The portion where marks are formed diffracts reflection light depending on whether or not the marks exist at respective positions on the disk. Therefore, the average level of the amount of reflection light is low compared with that of the mirror portion.
FIG. 3B
shows a change in amount of reflection light. Since the repetition frequency of the marks is higher than the period of the PEP bit cells, mark signal components can be eliminated by limiting the band for a reproduction signal. The waveform of the reproduction signal obtained by band limit is shown in FIG.
3
C. The information of each PEP bit cell can be detected by examining the level of the reproduction signal.
Then, the inner and outer SFP regions of the control information track will be described. The same information is recorded in the inner and outer SFP regions. That is, prerecord marks are recorded in the inner and outer SFP regions under a standard user data format. A 512 B region is allocated for the control data signals. For example, the same information as the 18 B information recorded in the PEP regions is recorded in bytes 0 to 17. The details on other control information to be recorded in this region are specified in the aforementioned JIS standard. The description thereof is therefore omitted here.
FIG. 6
shows an example of the standard user data format of each sector where the user data capacity is 512 B and Format A is used. The numbers shown in
FIG. 6
represent the numbers of bytes (B) allocated to respective signals. The capacity of the data region becomes 650 B including an error correction code, resynchronization bytes, and control bytes in addition to the 512 B user bytes.
This sector for recording signals in the data region also includes the following regions: a prerecorded address section composed of a sector mark (SM) indicating the head of the sector, a VFO region for synchronizing clock reproduction, an ID region indicating the address of the sector, an address mark (AM) indicating the head of the ID region, and the like; and regions for rewriting data, such as an offset detection region (ODF), an ALPC used for detection of laser output, and a buffer region provided to avoid overlap with a subsequent sector.
The total capacity of the sector is therefore 746 B. Although the control data recorded in the SFP regions are prerecord marks, the capacity of 746 B is required to record the 512 B control signals, as in the case of recording user data, since the control data is recorded under the user data format.
In recent years, read-only optical disks in which digitized and compressed image and sound signals are recorded have been proposed.
FIGS. 7A
to
7
C show an example of a sector format of one of such read-only optical disks called a DVD (digital video disk).
A 2048 B unit of information data such as image and sound is recorded in one sector. This unit is called a first data signal. The sector also includes a 4 B data ID, a 2 B IED for error detection of the data ID, a 6 B RSV as reservation, and a 4 B EDC for error detection of the entire sector. Such one sector including these regions is called a first data unit.
FIG. 7A
shows a configuration of the first data unit which has a data length of 2048+4+2+6+4=2064 (B).
The information data (2048 B) is scrambled in the following manner. A shift register is constructed so that so-called M-series data is generated. An initial value is set for the shift register, and is sequentially shifted in synchronization with the data, so as to generate pseudorandom data. An exclusive-OR between the generated pseudorandom data and the information data to be recorded is calculated every bit. Thus, the information data (2048 B) is scrambled.
A total of 16 sectors of the thus-scrambled first data units are put together to constitute an error correction code of Reed Solomon coding. In such an error correction code, each data unit constituting one sector is arranged in an array of 172 B×12 rows and a total of 16 sectors of such data units are put together to constitute an array of 172 B×192 rows. A 16 B outer cod
Ishida Takashi
Ohara Shunji
Satoh Isao
Takemura Yoshinari
Matsushita Electric - Industrial Co., Ltd.
Neyzari Ali
Renner , Otto, Boisselle & Sklar, LLP
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