Dynamic information storage or retrieval – With servo positioning of transducer assembly over track... – Optical servo system
Reexamination Certificate
1999-06-30
2003-01-07
Young, W. R. (Department: 2651)
Dynamic information storage or retrieval
With servo positioning of transducer assembly over track...
Optical servo system
C369S047300, C369S047500, C369S275300, C369S275400
Reexamination Certificate
active
06504800
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a data writable and readable optical disk and an optical disk apparatus for driving the optical disk.
A rewritable optical disk allows repetitive writing and reading of data at arbitrary positions. In general, data are recorded on such an optical disk in units of sectors. In this case, sector address information and error correction coded data are written in each sector.
In contrast to this, on a large-capacity rewritable optical disk called a DVD-RAM, which has recently been standardized to have a diameter of 120 mm, in order to improve the data error correction performance, data are written in units of ECC blocks each obtained by performing error correction coding throughout a plurality of sectors. The same writing (recording) method is used for a DVD-ROM as a read-only optical disk, in which data are written in units of ECC blocks each having 16 sectors each including 2,048 bytes. In the DVD-ROM, error correction coding is applied to ECC blocks and sector address information as well as data, thus realizing a structure that is highly resistant to errors.
As an optical disk on which data are recorded in units of ECC blocks in the above manner, the following optical disk has been proposed, together with an optical disk apparatus. According to this proposal, the optical disk is designed to write/read out (record/reproduce) data in units of ECC blocks each having a plurality of sectors by using at least a land track or groove track. A separation portion is formed on a groove track to be flush with a land track surface. The position information of an ECC block (information representing the address of the ECC block or the boundary between ECC blocks) is recorded as embossed pits on the boundary between this separation portion and the land track. Error correction coded data is written in each sector of the ECC block on the basis of the position information obtained from the embossed pits, together with sector address information representing the address of each sector in which data is written.
As described above, the position information of each ECC block (ECC block) is recorded as embossed pits on an optical disk. When data of each sector of the ECC block and the address information of each sector are recorded on the optical disk on the basis of this position information, the sector length on the disk changes due to variations in the rotational speed of the disk in data record/reproduce operation or decentering, or random shifts of the record position in the use of a phase change recording scheme and deterioration at the beginning/end of data occur. For this reason, to cope with random shifts and deterioration at the beginning/end of data, buffer areas are formed in units of ECC blocks. Since the buffer areas are reduced as compared with a conventional optical disk on which address information is recorded as embossed pits in units of sectors, the data record area can be increased accordingly, thus increasing the format efficiency.
In the above arrangement, however, buffer areas are formed in units of ECC blocks, and data are recorded in units of ECC blocks. For this reason, separation portions in which embossed pits are formed cannot be aligned in the radial direction of the disk, and general data record/reproduce operation is performed on tracks adjacent to tracks in which embossed pits are formed. If, therefore, the recording density increases (the track pitch decreases) in the tracking direction, crosstalk between embossed pits and record data on adjacent tracks may present a problem. When land tracks adjacent to a separation portion in which embossed pits are formed are to be reproduced, the crosstalk suppression effect in the land/groove arrangement cannot be obtained. This may affect reproduction of data.
Consider land tracks adjacent to a separation portion in which embossed pits are formed. Although a groove is present on one side, the land on the other side is flat. In this case, a problem regarding record/reproduction operation itself, i.e., a problem that an accurate shape record mark cannot be formed or the DC component of a reproduction signal may greatly change may arise, unlike the record/reproduction characteristics of a conventional land track in which groove tracks are present on the two sides of embossed pits.
In addition, since the land portion on this groove track separation portion is spread, the shape of a record mark distorts, and the mark center deviates from the center of the land track. As a result, the intensity of reflected light in reproduction operation differs from that from a land track having groove tracks on its two sides in reproduction operation. It may therefore become difficult to stably perform data record/reproduction operation.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide an optical disk and optical disk apparatus which can increase a format efficiency and record data at arbitrary positions without any waste.
It is another object of the present invention to provide an optical disk apparatus which can record/reproduce data more stably on/from a land track partial region adjacent to a land portion of a groove track separation portion on an optical disk.
According to the present invention, there is provided an optical disk on/from which data can be recorded/reproduced in units of ECC blocks each constituted by a plurality of sectors, comprising a plurality of land tracks and groove tracks which are alternately arranged in a radial direction of the optical disk, a land portion which is formed on each of the groove tracks to separate a corresponding groove track of the groove tracks and is substantially flush with the land tracks, a set of embossed pits which is formed in units of ECC blocks in a boundary between the land portion and one of the land tracks located on two sides of the groove track in which the land portion is formed, and a record/reproduction interruption portion which is formed in a data area adjacent to the land portion and on the other of the land tracks located on the two sides on a side on which the set of embossed pits are not formed, no data being recorded/reproduced on/from the record/reproduction interruption portion.
In addition, according to the present invention, there is provided optical disk apparatus for recording/reproducing data on/from at least one of land and groove tracks on an optical disk in units of ECC blocks each having a plurality of sectors, comprising an optical head which records/plays back information on/from at least one of the land and groove tracks on the optical disk, and a processor which detects logical position information by which the ECC blocks are separated on the basis of position information obtained by a set of embossed pits and a record/reproduction interruption portion between the ECC blocks and performs a processing of temporarily interrupting recording/reproduction of data on/from the record/reproduction interruption portion, when data of each sector and address information of each sector are recorded/reproduced on the basis of the position information read by the optical head from the set of embossed pits formed in a boundary between each of the land tracks and a land portion for separating a corresponding one of the groove tracks on the optical disk.
When position information by which an ECC block is separated into a plurality of blocks is to be generated, a logical position at which the ECC block is separated may be located immediately before a sync pattern in a data area, immediately before sector address information, or immediately after the sector address information.
When the position information or the like of an ECC block on an optical disk is recorded as embossed pits, and the data of each sector of the ECC block and the address information of each sector are to be recorded on the basis of this position information, logical position information by which the ECC block is separated into a plurality of blocks and a record/reproduction interruption portion inserted between the p
Kuwahara Maho
Takehara Shintaro
Kabushiki Kaisha Toshiba
Pillsbury & Winthrop LLP
Young W. R.
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