Dynamic information storage or retrieval – Information location or remote operator actuated control – Selective addressing of storage medium
Reexamination Certificate
2000-04-12
2002-05-07
Dinh, Tan (Department: 2651)
Dynamic information storage or retrieval
Information location or remote operator actuated control
Selective addressing of storage medium
C369S044370
Reexamination Certificate
active
06385143
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical disc read apparatus and method, and more particularly to an optical disc read apparatus and method in which different light beams are applied at the same time to a plurality of adjacent tracks of an optical disc formed with a spiral track, such CD-ROM, CD-WO, DVD, DVD-ROM, and DVD-RAM, and data recorded on the tracks applied with the light beams are read with a record data read system in accordance with a detected output of each reflected light beam.
2. Description of the Related Art
A multibeam method is one of the methods of reading record data from a CD-ROM at high speed. With this method, different light beams are applied at the same time to a plurality of adjacent tracks of an optical disc formed with a spiral track, data recorded on the tracks applied with the light beams are read with a record data read system in accordance with a detected output of each reflected light beam, and the read data are sequentially output in the record order by preventing the read data from being duplicated or omitted.
A multibeam method of reading an optical disc (CD-ROM) will be described with reference to FIG.
21
. Reference numeral
1
represents an optical disc (CD-ROM) as viewed toward a signal plane (from an optical pickup side), CD-ROM being formed with a spiral track recorded with data (the outer and inner circumference sides of CD-ROM are indicated by arrows in FIG.
21
). Reference numeral
2
represents an optical pickup capable of radiating five light beams, the optical pickup
2
being provided with a relative rotation to CD-ROM
1
and moved from the inner circumference to outer circumference as record data read advances. As the optical pickup
2
reaches a position I and starts reading record data, light beams
3
1
to
3
5
are applied at the same time to respective tracks (x−1) to (x+3) and data recorded on the tracks applied with the light beams
3
1
to
3
5
are read with a record data read system in accordance with a detected output of each reflected light beam.
Record data of CD-ROM
1
is formed on the basis of one frame unit (one frame=1/75 sec) represented by A-time (Absolute-time) of a sub-code Q channel, in conformity with the CD signal format. As the optical pickup
2
starts reading data from the position I shown in
FIG. 21
, the optical beam
3
1
system correctly reads record data from the frame of A-time=23:40:59 or 23 minutes, 40 seconds, 59 frames, the optical beam
3
2
system correctly reads record data from the frame of A-time=23:40:74, the optical beam
3
3
system correctly reads record data from the frame of A-time=23:41:14, the optical beam
3
4
system correctly reads record data from the frame of A-time=23:41:29, and the optical beam
3
5
system correctly reads record data from the frame of A-time=23:41:44.
As CD-ROM
1
rotates generally once (slightly more than once) and the read position with the optical pickup
2
reaches a position II shown in
FIG. 21
(the light beams
3
1
to
3
5
are applied to the tracks x to (x+4), the optical beam
3
1
correctly reads record data up to the frame of A-time=23:40:73, the optical beam
3
2
correctly reads record data up to the frame of A-time=23:41:13, the optical beam
3
3
correctly reads record data up to the frame of A-time=23:41:28, and the optical beam
3
4
correctly reads record data up to the frame of A-time=23:41:43. In this manner, there is no omission of read data by the optical beams
3
1
to
3
5
(at this time, the light beam
3
5
has correctly read record data up to the frame of A-time=23:41:58). The data read by the optical beams
3
1
to
3
5
are output to external circuits in the record order by preventing the read data from being duplicated.
When the read position with the optical pickup
2
reaches the position II shown in
FIG. 21
, the optical pickup
2
is jumped forward (toward the outer circumference of CD-ROM
1
) by three tracks. Namely, the optical pickup
2
is jumped to a position III shown in
FIG. 21
(and the light beams
3
1
to
3
5
are applied to tracks (x+3) to (x+7)). Thereafter, data read starts again. Specifically, the optical beam
3
1
system correctly reads record data from the frame of A-time=23:41:46, the optical beam
3
2
system correctly reads record data from the frame of A-time=23:41:61, the optical beam
3
3
system correctly reads record data from the frame of A-time=23:42:01, the optical beam
3
4
system correctly reads record data from the frame of A-time=23:42:16, and the optical beam
3
5
system correctly reads record data from the frame of A-time=23:42:31.
As CD-ROM
1
rotates generally once (slightly more than once) and the read position with the optical pickup
2
reaches a position IV shown in
FIG. 21
(the light beams
3
1
to
3
5
are applied to the tracks (x+4) to (x+8), the optical beam
3
1
system correctly reads record data up to the frame of A-time=23:41:60, the optical beam
3
2
system correctly reads record data up to the frame of A-time=23:42:00, the optical beam
3
3
system correctly reads record data up to the frame of A-time=23:42:15, and the optical beam
3
4
system correctly reads record data up to the frame of A-time=23:42:30. In this manner, there is no omission of read data by the optical beams
3
1
to
3
5
(at this time, the light beam
3
5
has correctly read record data up to the frame of A-time=23:42:45). The data read by the optical beams
3
1
to
3
5
are output to the external circuits in the record order by preventing the read data from being duplicated.
When the read position with the optical pickup
2
reaches the position IV shown in
FIG. 21
, the optical pickup
2
is jumped forward (toward the outer circumference of CD-ROM
1
) by three tracks. Namely, the optical pickup
2
is jumped to a position V shown in
FIG. 21
(and the light beams
3
1
to
3
5
are applied to tracks (x+7) to (
3
+11)). Thereafter, data read starts again. Specifically, the optical beam
3
1
system correctly reads record data from the frame of A-time=23:42:33, the optical beam
3
2
system correctly reads record data from the frame of A-time=23:42:48, the optical beam
3
3
system correctly reads record data from the frame of A-time=23:42:63, the optical beam
3
4
system correctly reads record data from the frame of A-time=23:43:03, and the optical beam
3
5
system correctly reads record data from the frame of A-time=23:43:18.
As CD-ROM
1
rotates generally once (slightly more than once) and the read position with the optical pickup
2
reaches a position VI shown in
FIG. 21
(the light beams
3
1
to
3
5
are applied to the tracks (x+8) to (x+12), the optical beam
3
1
system correctly reads record data up to the frame of A-time=23:42:47, the optical beam
3
2
system correctly reads record data up to the frame of A-time=23:42:62, the optical beam
3
3
system correctly reads record data up to the frame of A-time=23:43:02, and the optical beam
3
4
system correctly reads record data up to the frame of A-time=23:43:17. In this manner, there is no omission of read data by the optical beams
3
1
to
3
5
(at this time, the light beam
3
5
has correctly read record data up to the frame of A-time=23:43:32). The data read by the optical beams
3
1
to
3
5
are output to the external circuits in the record order by preventing the read data from being duplicated.
When the read position with the optical pickup
2
reaches the position VI shown in
FIG. 21
, the optical pickup
2
is jumped forward (toward the outer circumference of CD-ROM
1
) by three tracks. Namely, the optical pickup
2
is jumped to a position VII shown in
FIG. 21
(and the light beams
3
1
to
3
5
are applied to tracks (
3
+11) to (x+15)). Thereafter, data read starts
Dinh Tan
Kabushiki Kaisha Kenwood
Nixon & Peabody LLP
Robinson Eric J.
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