Dynamic information storage or retrieval – Binary pulse train information signal – Including sampling or a/d converting
Reexamination Certificate
1999-02-26
2003-04-22
Psitos, Aristotelis M. (Department: 2653)
Dynamic information storage or retrieval
Binary pulse train information signal
Including sampling or a/d converting
C369S053330
Reexamination Certificate
active
06552988
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an information reproducing apparatus for reproducing digital information recorded on a DVD-RAM (DVD random Access Memory) by a single spiral land/groove recording method.
2. Description of the Related Art
A DVD-RAM is a recording medium whose storage capacity is about four times as large as that of a CD (Compact Disk), and it is a recordable recording medium which enables a user to rewrite information thereon several times.
FIG. 1
shows the recording surface of the DVD-RAM
1
. As shown in
FIG. 1
, a land track
1
L and a groove track
1
G are formed in a spiral form on the recording surface of the DVD-RAM
1
. The land track
1
L and the groove track
1
G are alternately arranged in the radial direction of the DVD-RAM
1
.
Digital information is recorded on such a recording surface according to a predetermined recording format based on a DVD standard. A “single spiral-land/groove (SS-L/G) recording method” is standardized as one recording format of the DVD-RAM in the DVD standard. This method is described in a paper: “Accessing method for single spiral-land groove recording” by Nakane et al., published in Technical Report of IEICE (the Institute of Electronics, Information and Communication Engineers), MR95-88, PCM95-126 (February 1996).
The single spiral land/groove recording method is adopted as the recording format of the DVD-RAM
1
shown in FIG.
1
. In the single spiral-land/groove recording method, the digital information is recorded on both of the land track
1
L and groove track
1
G.
The digital information to be recorded on the DVD-RAM
1
is divided into sectors. The amount of the divided digital information contained in each sector is predetermined. Each of the land track
1
L and groove track
1
G are also divided into sectors corresponding to the sectors of the digital information, as shown in FIG.
1
.
Control information recording areas S
0
-S
7
are formed at the respective boundaries between neighboring sectors, as shown in FIG.
1
. Hereinafter, the control information recording area is referred to as a “CIR area”. The CIR areas S
0
-S
7
are located at equiangular intervals in the direction of the rotation of the DVD-RAM
1
.
At the CIR area S
0
, the arrangement of the land track
1
L and groove track
1
G are switched over to each other in the radial direction of the DVD-RAM
1
. Namely, at the CIR area S
0
, the land track
1
L is switched over to the groove track
1
G, and the groove track
1
G is switched over to the land track
1
L. In other words, the land track
1
L and the groove track
1
G are substantially connected with each other through the CIR area S
0
. This structure enables the digital information to be continuously recorded onto or reproduced from both of the land track
1
L and groove track
1
G. In addition, at other CIR areas S
1
-S
7
, the land track
1
L and groove track
1
G are not switched over.
Control information is pre-recorded in each of the CIR areas S
0
-S
7
. The control information includes address information to substantially identify positions on the recording surface of the DVD-RAM
1
. This information is needed for a recording process or a reproduction process of the digital information. For example, the control information includes information representing a physical position or a sector number to identify the sector located immediately after or before the CIR area.
FIG. 2
is enlarged view of a part of the recording surface of the DVD-RAM
1
, which includes the CIR areas S
0
and S
1
, and which is indicated by a broken line DL
1
in FIG.
1
. As shown in
FIG. 2
, the CIR area S
0
is divided into two equal areas in the circumferential direction D
1
of the DVD-RAM
1
, which is shown by an arrow in FIG.
2
. Each of the two equal areas is further divided into pre-recorded parts
70
and blank parts
71
in the radial direction D
2
of the DVD-RAM
1
, which is shown by another arrow in FIG.
2
. Each of the pre-recorded parts
70
and the blank parts
71
is equal to the groove track
1
G or the land track
1
L in width (length in the radial direction D
2
). The pre-recorded parts
70
and the blank parts
71
are alternately located in each of the two equal areas in the radius direction D
2
. Each pre-recorded part
70
on the right side of the CIR area S
0
is located ½ width out of the location of the groove track
1
G in the radial direction D
2
. In contrast, each pre-recorded part
70
on the left side of the CIR area S
0
is located ½ width out of the location of the groove track
1
G in the radial direction D
3
(opposite to the radial direction D
2
).
Control information is pre-recorded in each pre-recorded part
70
as pits P. In contrast, there is no pit on each blank part
71
, so that the surface of each blank part
71
is like a mirror. This means that no information is recorded on each blank part
71
. Each blank part
71
is equal to the land track
1
L in height. The structure of each of the other CIR areas S
1
-S
7
is the same as that of the CIR area S
0
.
When the digital information and the control information are read out from the DVD-RAM
1
, a light beam is emitted from an optical pickup to the recording surface of the DVD-RAM
1
. At this time, a light spot LS is formed by the light beam. The light spot LS is moved on the land track
1
L and the groove track
1
G alternately by the revolution of the DVD-RAM
1
and the movement of the pickup in the radial direction of the DVD-RAM
1
. For example, the light spot LS is first moved on the groove track
1
G. After the light spot has passed the CIR area S
0
, the light spot LS is next moved on the land track
1
L. After the light spot LS has passed the CIR area S
0
again, the light spot LS is next moved on the groove track
1
G. In such a manner, the light spot LS is alternately moved on the groove track
1
G and the land track
1
L.
As shown in
FIG. 2
, the light spot LS is passed on an imaginary track T
1
in the CIR area S
0
, when the light spot LS is moved from the groove track
1
G to the land track
1
L through the CIR area S
0
. When the light spot LS is passed on the imaginary track T
1
, the light spot LS is first passed on the pre-recorded part
70
located ½ width out of the location of the groove track
1
G in the direction D
3
, and the light spot LS is next passed on the neighbor pre-recorded part
70
located ½ width out of the location of the groove track
1
G in the opposite direction D
2
.
The light spot is passed on an imaginary track T
2
in the CIR area S
0
, when the light spot LS is moved from the land track
1
L to the groove track
1
G through the CIR area S
0
. When the light spot LS is passed on the imaginary track T
2
, the light spot LS is first passed on the pre-recorded part
70
located ½ width out of the location of the land track
1
L in the direction D
2
, and the light spot LS is next passed on the neighbor pre-recorded part
70
located ½ width out of the location of the land track
1
L in the opposite direction D
3
.
The light spot is passed on an imaginary track T
3
in the CIR area S
1
(S
2
-S
7
), when the light spot LS is moved from a certain sector to the neighboring sector on the same groove track
1
G. When the light spot LS is passed on the imaginary track T
3
, the light spot LS is first passed on the pre-recorded part
70
located ½ width out of the location of the groove track
1
G in the direction D
2
, and the light spot LS is next passed on the neighbor pre-recorded part
70
located ½ width out of the location of the groove track
1
G in the opposite direction D
3
.
The light spot is passed on an imaginary track T
4
in the CIR area S
1
(S
2
-S
7
), when the light spot LS is moved from a certain sector to the neighboring sector on the same land track
1
L. When the light spot LS is passed on the imaginary track T
4
, the light spot LS is first passed on the pre-recorded part
70
located ½ width out of the location of the land track
Hayashi Hideki
Nishiwaki Hiroshi
Pioneer Electric Corporation
Psitos Aristotelis M.
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