Dynamic information storage or retrieval – Storage medium structure – Optical track structure
Reexamination Certificate
2002-07-11
2004-05-18
Edun, Muhammad (Department: 2655)
Dynamic information storage or retrieval
Storage medium structure
Optical track structure
C369S275300, C369S053340, C369S059100
Reexamination Certificate
active
06738342
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optically rewritable optical disc and to an apparatus and method for reading addresses prewritten to the optical disc.
2. Description of Related Art
DVD-RAM, CD-RW, and MD are examples of user-recordable optical discs that have become available in the last few years. This type of recordable optical disc has grooves formed along a spiral or plural concentric tracks with a phase change material or magneto-optical material formed on the groove surface. Addresses for specifying a particular location on the disc are also pre-recorded to the tracks using rewritable marks. This type of address is described in Japanese Patent Laid-Open Publication (kokai) H8-315426.
Kokai H8-315426 describes providing discontinuities in the grooves and using these discontinuous parts for forming a pattern corresponding to the address signal. A pattern corresponding to the address signal is a binary signal that inverts at each discontinuity, an on/off signal used for generating an ATIP (Absolute Time Pregroove) signal. The discontinuities are therefore used simply as a signal indicating presence or absence.
SUMMARY OF THE INVENTION
(Technical Problem to be Solved)
More address values and a method for more efficiently assigning address values is needed in order to create an optical disc with an even higher recording density. In an optical disc according to the related art, however, the discontinuities are nothing more than a trigger signal for signal inversion and can carry only one piece of information (trigger data). Numerous marks are therefore required.
Furthermore, the approximate location of a track can be detected with the ATIP signal, but the position where recording starts cannot be precisely determined. This means that when appending a new recording after recording once, or when overwriting data in the middle of a previous recording, new data may be recorded over previously recorded data that is still necessary. Crosstalk also occurs more easily when the track pitch is reduced.
The present invention is directed to a solution for these problems and provides an optical disc wherein discontinuities or modifications are formed in the grooves and two or more meanings are imparted to the discontinuities or modifications in order to provide address information more efficiently.
A further object of the invention is to provide an optical disc whereby the positioning precision of the recording start point can be increased.
A yet further object of the invention is to provide an optical disc enabling the track pitch to be reduced.
A yet further object of the invention is to provide an optical disc that is recordable and playable with full CLV (constant linear velocity) control.
A yet further object of the invention is to provide an apparatus and method of simple design for accurately reading address information from an optical disc having address information containing two or more meanings imparted to discontinuities or modifications formed in the grooves.
The invention as described in claim 1 is a rewritable optical disc with a spiral or concentric track comprising:
a groove formed with a sinusoidal wobble along the track;
a sector block disposed along the track;
sectors formed by dividing each sector block into a plurality of parts;
a synchronization mark formed in the first sector in each sector block; and
positive marks or negative marks formed in sectors other than the first sector in each sector block;
each positive mark being a first groove discontinuity creating a discontinuity of a first width W
1
in the track direction of the groove,
each negative mark being a second groove discontinuity creating a discontinuity of a second width W
0
in the track direction of the groove, and
each synchronization mark being a third groove discontinuity creating a discontinuity of a third width Ws in the track direction.
The invention as described in claim 2 is an optical disc as described in claim 1, wherein the first, second, and third groove discontinuities have a mirror surface.
The invention as described in claim 3 is an optical disc as described in claim 1, wherein the first, second, and third groove discontinuities are formed in maximum amplitude parts of the wobble groove.
The invention as described in claim 4 is an optical disc as described in claim 1, wherein the first, second, and third groove discontinuities are formed in the minimum amplitude part of the wobble groove.
The invention as described in claim 5 is an optical disc as described in claim 1, wherein the first, second, and third widths W
1
, W
0
, and Ws are all longer than the longest mark contained in data recorded to a groove and less than or equal to ½ wobble period.
The invention as described in claim 6 is an optical disc as described in claim 1, wherein the first, second, and third widths W
1
, W
0
, and Ws are all longer than the longest mark contained in data recorded to a groove and less than or equal to ¼ wobble period.
The invention as described in claim 7 is an optical disc as described in claim 1, wherein the ratio between first, second, and third widths W
1
, W
0
, and Ws is 1:2:4 where any one of widths W
1
, W
0
, and Ws is 1.
The invention as described in claim 8 is an optical disc as described in claim 1, wherein the ratio between first, second, and third widths W
1
, W
0
, and Ws is 2:1:4.
The invention as described in claim 9 is an optical disc as described in claim 1, wherein the first, second, and third widths W
1
, W
0
, and Ws are two bytes, one byte, and four bytes, respectively.
The invention as described in claim 10 is a rewritable optical disc with a spiral or concentric track comprising:
a groove formed with a sinusoidal wobble along the track;
a sector block disposed along the track;
sectors formed by dividing each sector block into a plurality of parts;
a synchronization mark formed in the first sector in each sector block; and
positive marks or negative marks formed in sectors other than the first sector in each sector block;
each positive mark, negative mark, and synchronization mark being formed as a groove top offset portion where the groove is locally offset in a first direction perpendicular to the track direction, a groove bottom offset portion where the groove is locally offset in a second direction perpendicular to the track direction, or a combination of groove bottom offset portions and groove top offset portions.
The invention as described in claim 11 is an optical disc as described in claim 10, wherein:
a positive mark is a groove top offset portion;
a negative mark is a groove bottom offset portion; and
a synchronization mark is a combination of a groove top offset portion and groove bottom offset portion.
The invention as described in claim 12 is an optical disc as described in claim 10, wherein the groove bottom offset portions and groove top offset portions are disposed at maximum amplitude parts of the wobble groove and are offset in a track center direction.
The invention as described in claim 13 is an optical disc as described in claim 10, wherein groove bottom offset portions and groove top offset portions of a synchronization mark are mutually adjacent at n+(½) wobble cycles (where n is a positive integer).
The invention as described in claim 14 is an optical disc as described in claim 13, wherein n is 0.
The invention as described in claim 15 is a rewritable optical disc with a spiral or concentric track comprising:
a groove formed with a sinusoidal wobble along the track;
a sector block disposed along the track;
sectors formed by dividing each sector block into a plurality of parts;
a synchronization mark formed in the first sector in each sector block; and
positive marks or negative marks formed in sectors other than the first sector in each sector block;
each positive mark, negative mark, and synchronization mark being formed by a groove ascending-phase inversion part for vertically phase inverting an approximately ¼ wobble cycle part from a trough in the wobble gr
Furumiya Shigeru
Ishibashi Hiromichi
Ishida Takashi
Kobayashi Yoshiharu
Edun Muhammad
Wenderoth , Lind & Ponack, L.L.P.
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