Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
2000-03-17
2001-04-03
Tran, Thang V. (Department: 2651)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
C369S053130
Reexamination Certificate
active
06212145
ABSTRACT:
BACKGROUND OF INVENTION
The present invention relates to an apparatus for and a method of recording data on and reproducing data from an optical disk having concentric or spiral recording tracks formed of grooves and lands between the grooves, with the land and groove tracks being divided into sectors, and with address areas for the respective sectors being disposed between the center of a groove and the center of a land adjacent to each other, so that during reproduction of a track, an address for a sector in the track and an address for a sector in an adjacent track are both reproduced.
In a typical example, the address areas for the respective tracks are shifted in one radial direction (e.g., radially outwards), and during reproduction of the track, the address for a sector in the track and the address for a sector in another track adjacent to and disposed in the other radial direction (e.g., radially inward) of the first-mentioned track are both reproduced.
As a data recording method for a large-capacity rewritable optical disk, with an increased recording density, a land/groove recording method has been proposed in which data is recorded both onto the grooves of guide grooves (also referred to G), and onto lands (also referred to L) between the grooves. When this method is used, the recording density can be increased because the track pitch can be halved compared to an optical disk which has the same groove pitch but does not use this method. Grooves and lands may also be referred to as depressed portions and projecting portions, respectively.
An example of conventional land/groove recording optical disk, disclosed in Japanese Examined Patent Application Publication 63-57859 is shown in FIG.
11
. As illustrated, grooves
94
and lands
95
are formed by means of guide grooves inscribed on the substrate of the disk, and a recording layer
91
is formed thereon. Recording pits
92
are formed on the recording layer
91
on the grooves
94
and the lands
95
. The grooves
94
and the lands
95
form separate continuous recording tracks. That is, the guide grooves are continuous on the disk, so that the recording tracks of the grooves
94
form a continuous recording spiral, and the recording tracks of the lands
95
form a separate continuous recording spiral. A light spot
93
generated by an optical disk drive apparatus records data on or reproduces data from the optical disk, while scanning either of the recording tracks of the lands and the grooves.
In another format, which is shown in
FIG. 12
, lands and grooves are connected at every revolution to form a single spiral in which lands L and grooves G alternate at very revolution. More specifically, a recording track of a groove (hereinafter referred to as a groove track) having a length corresponding to a revolution of the disk and a recording track of a land (hereinafter referred to as a land track) having a length corresponding to a revolution of the disk are connected alternately to form a recording spiral. This format is herein referred to as a single spiral land/groove format, or an SS-L/G format.
The recording surface of the optical disk is divided into a plurality of annular zones (Z1, Z2), and each revolution of the track is divided into an integer number of sectors RS having an identification data area IDF. The number of sectors per track is progressively increased by “one” toward the outermost zone. In the example shown in
FIG. 12
, the disk is divided into two zones (Z1, Z2), and the number of sectors per track is three in the inner zone Z1, and is four in the outer zone Z4.
FIG. 13
schematically shows the arrangement of identification data area IDF and the address values recorded within a recording sector RS of an optical disk used with a conventional optical disk drive apparatus. n represents an address of a certain sector, and N represents the number of sectors per track. The identification data area IDF is composed of four PIDs (Physical IDs) and divided into a front part FP and a rear part RP in the beam spot scanning direction SCN. Each of the front part FP and the rear part RP is composed of two PIDs. The front part FP is shifted radially outwards (OP) by half a groove width Dw/2 from the center of a groove, while the rear part RP is shifted radially inwards (IP) by half the groove width from the center of the groove.
A method of providing identification data such as a sector address in the identification data area IDF is described next. The address of a groove track sector is assigned to the front part FP of the identification data area IDF which is immediately before the data recording area DRF of the groove track sector, being shifted by half a groove width radially outwards from the center of the groove. On the other hand, the address of a land track sector is assigned to a rear part RP of the identification data area IDF which is immediately before the data recording area DRF in a groove track sector adjacent to and disposed radially outward of the above-mentioned land track sector, being shifted radially inwards by half the groove width from the center of the groove. Consequently, the address of a land track sector is assigned to the rear part RP of the identification data area IDF in a groove track sector, which is immediately before the data recording area DRF of the land track sector, and which is shifted radially outwards by half a groove width from the center of the land. In this way, the address of a land track sector is added to a groove rather than to a land, and an identification data area IDF in a land track sector contains no identification data.
An advantage of having the identification data shifted by half a groove width from the center of a track is that the identification data are shared between a groove track and a land track adjacent to each other, so that the identification data are read with a substantially the same quality, regardless of whether a track sector being scanned is in a land or a groove. When the width of a groove is not identical to a track pitch, the amount of the shift may be set to half a track pitch.
For simplifying the description, it is assumed in
FIG. 13
that an identification data area IDF is composed of four PIDs alone. The identification data area IDF may further contain other information such as a header mark or servo control data. Also, synchronization data for address reading, and error detection or error correction codes may also be provided as is known in the art.
Now, description is directed to the prepits in identification data areas around a land/groove connecting points, which are present at every revolution of a disk and which are aligned in a radial direction of the disk, and a method of assigning addresses to such identification data areas.
FIG. 14
schematically shows the arrangement of identification data areas within the sectors around connecting points or boundaries between lands and grooves, and the address values assigned thereto. In an SS-L/G format optical disk, there is a boundary extending in the radial direction, at which a land track and a groove track are connected at every revolution of the disk. In a recording sector RS immediately after a land/groove connecting point, the front part FP of the identification data is shifted by half a groove width radially outwards from the center of the groove, and the rear part RP of the identification data area IDF is shifted by half a groove radially inwards from the center of the groove, as in the identification data areas IDF in other sectors (sectors which are not at the connecting points). The assignment of the addresses is also the same as in the sectors which are not at the connecting points. That is, the address of a groove track sector is assigned to the front part FP of the identification data area IDF which is immediately before the data recording area DRF and which is shifted radially outwards by half a groove width from the groove. The address of a land track sector is assigned to the rear part RP of the identification data area IDF which is immediately before the data re
Gotoh Kenji
Ishida Yoshinobu
Nakane Kazuhiko
Oohata Hiroyuki
Mitsubishi Denki & Kabushiki Kaisha
Tran Thang V.
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