Dynamic information storage or retrieval – Control of storage or retrieval operation by a control... – Control of information signal processing channel
Reexamination Certificate
2001-03-02
2003-03-25
Edun, Muhammad (Department: 2655)
Dynamic information storage or retrieval
Control of storage or retrieval operation by a control...
Control of information signal processing channel
C369S059100, C369S059250, C369S275400
Reexamination Certificate
active
06538965
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an optical disc such as a phase change optical disc or a magneto-optical disc. In addition, this invention relates to an apparatus for recording a digital information signal on an optical disc. Furthermore, this invention relates to an apparatus for reproducing a digital information signal from an optical disc. Also, this invention relates to an apparatus for recording and reproducing a digital information signal on and from an optical disc.
2. Description of the Related Art
A DVD-RW (DVD Rewritable) has a disc member formed with a spiral of a wobbling groove on and from which main information can be recorded and reproduced. The disc member has land portions between neighboring groove portions. A groove portion and a pair of land portions adjoining the groove portion compose a track portion. Auxiliary information (a land pre-pit signal) is previously recorded on the land portions. Specifically, the auxiliary information is represented by land pre-pits formed in the land portions.
Japanese patent application publication number 9-326138 discloses an optical disc formed with wobbling grooves and pits (land pre-pits). The pits are located in an area between the grooves, and are spaced at a prescribed interval. During the recording of a signal on the disc or the reproduction of a signal therefrom, rotation of the disc is controlled in response to a wobble signal detected from the grooves. In addition, the position of a point on the disc is detected from a pit signal (a land pre-pit signal) derived from the pits.
The DVD-RW and the optical disc in Japanese patent application publication number 9-326138 are subjected to CLV (constant linear velocity) control during signal recording or signal reproduction. The CLV control causes the following problems.
(1) The phases of neighboring wobbles become opposite at some places. At these places, the cross-talks between a desired signal reproduced from the currently-scanned track and signals on tracks neighboring the currently-scanned track are relatively great. Accordingly, these places have a bad influence on signal recording. The quality of a land pre-pit signal reproduced from these places tends to be relatively low.
(2) In the case of data seek which requires an optical head to move radially of the disc for a large distance, a long time is taken until the rotational speed of the disc falls into a suitable range.
(3) If land pre-pits along neighboring tracks had equal phases, signal reproduction could be unavailable. Accordingly, it is necessary to design land pre-pits along neighboring tracks to have different phases.
Japanese patent application publication number 10-255330 discloses an optical disc having wobbling grooves which are designed to equalize the phases of the wobbles of neighboring grooves. The optical disc in Japanese patent application publication number 10-255330 can solve the above-indicated problem (1).
SUMMARY OF THE INVENTION
It is a first object of this invention to provide an improved optical disc.
It is a second object of this invention to provide an improved apparatus for recording a digital information signal on an optical disc.
It is a third object of this invention to provide an improved apparatus for reproducing a digital information signal from an optical disc.
It is a fourth object of this invention to provide an improved apparatus for recording and reproducing a digital information signal on and from an optical disc.
A first aspect of this invention provides an optical disc having an information recording portion, the information recording portion having a spiral of a groove, the information recording portion having land portions located between portions of the groove which neighbor each other as viewed in a disc radial direction, wherein auxiliary information used when an information signal is recorded on and reproduced from the groove is previously recorded on the land portions, wherein the auxiliary information is represented by pre-pits provided in the land portions, wherein the information recording portion is divided into a plurality of zones as viewed in the disc radial direction, wherein in each of the zones, at least one of two sides of the groove wobbles at a fixed frequency in accordance with a constant angular velocity system, and wherein in each of the zones, phases of wobbles of respective neighboring portions of the groove are equal to each other, and the neighboring portions of the groove neighbor each other as viewed in the disc radial direction.
A second aspect of this invention is based on the first aspect thereof, and provides an optical disc wherein the pre-pits are at positions having approximately a fixed relation with a period of the wobble of the groove, wherein groups each having a predetermined number of pre-pit locations represent bit data values containing addresses of the zones, and wherein a pre-pit is present in or absent from each of the pre-pit locations.
A third aspect of this invention is based on the second aspect thereof, and provides an optical disc wherein the groups in first one of the land portions are at first positions, and the groups in second one of the land portions are at second positions, wherein the first one of the land portions and the second one of the land portions neighbor each other as viewed in the disc radial direction, and wherein a phase of the first positions differ from a phase of the second positions as viewed along a disc circumferential direction.
A fourth aspect of this invention is based on the second aspect thereof, and provides an optical disc wherein the groups have first groups each representing a bit data value of “1” and second groups each representing a bit data value of “0”, wherein each of the first groups and each of the second groups are equal in number of pre-pits per group, and wherein each of the first groups and each of the second groups are different in arrangement of pre-pits per group.
A fifth aspect of this invention is based on the first aspect thereof, and provides an optical disc wherein the frequency “fw” of the wobble of the groove and a channel bit clock frequency “fp” of the information signal are in a relation as follows:
fp=N·fw
where N denotes a natural number.
A sixth aspect of this invention is based on the first aspect thereof, and provides an optical disc wherein as the zone changes from one to the next in a disc radially outward direction, a number of cycles of the wobble increases by a predetermined natural number and an amount of the information signal increases by a predetermined number of recording units.
A seventh aspect of this invention is based on the first aspect thereof, and provides an optical disc wherein the information recording portion is divided into a plurality of sectorial segments of equal angular sizes, and wherein as the zone changes from one to the next in a disc radially outward direction, a number of cycles of the wobble per sectorial segment increases by a predetermined natural number and an amount of the information signal per sectorial segment increases by a predetermined number of recording units.
An eighth aspect of this invention provides an apparatus for recording digital information on an optical disc having an information recording portion, the information recording portion having a spiral of a groove, the information recording portion having land portions located between portions of the groove which neighbor each other as viewed in a disc radial direction, wherein auxiliary information used when an information signal is recorded on and reproduced from the groove is previously recorded on the land portions, wherein the auxiliary information is represented by pre-pits provided in the land portions, wherein the information recording portion is divided into a plurality of zones as viewed in the disc radial direction, wherein in each of the zones, at least one of two sides of the groove wobbles at a fixed frequency “fw” in accordance with a constant angular velocity system, wherein in each of th
Hayami Atsushi
Mochizuki Masaki
Edun Muhammad
Victor Company of Japan Ltd.
Woo Louis
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