Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
2000-09-15
2004-11-23
Tran, Thang V. (Department: 2651)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
C369S044260
Reexamination Certificate
active
06822935
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a rewritable optical recording medium system, and more particularly to an apparatus and method for discriminating between a land track and a groove track in a land/groove recording system having the structure where a signal track is composed of the land and the groove.
2. Background of the Related Art
With the growth of audio and video media, optical recording/reproducing apparatus for recording and reproducing audio/video data on a semipermanent optical recording medium have been developed.
In case of the optical recording medium, as the storage capacity of the existing CD-ROM title reaches the uppermost limit, a digital versatile disc (DVD) is in the spotlight as a new optical recording medium. The DVD recognizes data in the same manner as a compact disc (CD) which recognizes data of “0” and “1” according to reflecting angles of a laser. However, the storage width of data in the DVD is minute in comparison to that in the CD.
Like the CD, the DVD is been developed from the technique of reproducing the data recorded on the disc to the technique of freely and repeatedly recording the data on the disc. In order to achieve this, various kinds of rewritable DVDs have been proposed lately. One among them, there exists a DVD where a disc track is divided into a land and groove (hereinafter referred to as ‘land/groove’ or ‘L/G’) tracks, and the data is recorded in the respective tracks (for instance, DVD-RAM).
FIG. 1
is a block diagram illustrating the construction of a typical apparatus for recording and reproducing data on the optical recording medium. Referring to
FIG. 1
, under the control of a servo control section
106
, an optical pickup
102
places an optical beam condensed through an object lens on a signal track of an optical recording medium, i.e., an optical disc
101
, and makes the optical beam reflected from a signal recording surface of the track condensed through the object lens and incident to an optical detector to detect a focus error signal and a tracking error signal. The optical detector is composed of several optical detecting elements, which output to a radio frequency (RF) and servo error generating section
104
electric signals in proportion to quantities of light obtained by the respective optical detecting elements.
For example, if the optical detector is composed of four optical detecting elements PDA, PDB, PDC, and PDD divided by four in a signal track direction and in a radial direction, the optical detector outputs to the RF and servo error generating section
104
electric signals a, b, c, and d in proportion to quantities of light obtained by the respective optical detecting elements PDA, PDB, PDC, and PDD.
The RF and servo error generating section
104
generates an RF signal required for data reproduction, read channel
2
signal required for servo control, focus error signal, etc., by combining the electric signals a, b, c, and d.
Here, the RF signal (also called ‘read channel
1
signal’) may be obtained by computing (a+b+c+d) of the electric signals outputted from the optical detector, and the read channel
2
signal by computing (a+d)−(b+c). The tracking error (TE) signal may be obtained by processing the read channel
2
signal.
Meanwhile, if the optical detector is divided by two in a track direction, i.e., into two photodiodes I
1
and I
2
, the RF signal (=I
1
+I
2
) and read channel
2
signal (=I
1
−I
2
) are detected from the balance of the light quantities of the photodiodes. In other words, a+d and b+c in
FIG. 2
correspond to I
1
and I
2
, respectively.
At this time, the RF signal is outputted to a data decoder
105
for data reproduction, the servo error signal such as FE and TE to a servo control section
106
, and the control signal for data recording to an encoder
103
.
The encoder
103
encodes the data to be recorded to recording pulses of a format required by the optical disc
101
, and records the pulses on the optical disc
101
through the optical pickup
102
. The decoder
105
restores the data of the original form from the RF signal.
Meanwhile, a host such as a personal computer (PC) may be connected to the optical disc recording/reproducing apparatus. This host transmits a recording/reproducing command to a microcomputer
111
through an interface
110
, transmits the data to be recorded to the encoder
103
, and receives reproduced data from the decoder
105
. The microcomputer
111
controls the encoder
103
, decoder
105
, and servo control section
106
in accordance with the recording/reproducing command from the host.
At this time, an advanced technology attached packet interface (ATAPI) is typically used as the interface
110
. Specifically, the ATAPI is the interface standard between the host and the optical recording/reproducing apparatus such as a CD or DVD driver proposed to transmit the data decoded by the optical recording/reproducing apparatus to the host, and serves to convert the decoded data into a protocol of a data packet that can be processed in the host and transmit the data packet.
Meanwhile, the servo control section
106
processes the focus error signal (FE), and outputs a driving signal for focusing control to a focus servo driving section
107
. The servo control section
106
also processes the tracking error signal (TE), and output a driving signal for tracking control to a tracking servo driving section
108
.
The focus servo driving section
107
moves the optical pickup
102
up and down by driving a focus actuator in the optical pickup
102
, so that the optical pickup
107
follows the movement of the rotating optical disc
101
.
The tracking servo driving section
108
moves the object lens of the optical pickup
102
in a radial direction by driving a tracking actuator in the optical pickup
102
, so that the object lens corrects the position of the optical beam, and follows the track.
If the DVD is a rewritable disc, for example, DVD-RAM, where the signal track is composed of the land and groove, the data can be recorded on or reproduced from both the land track and the groove track as well as either of the land track and the groove track. Here, the land track and the groove track have different depths in a light incident direction. For instance, the DVD-RAM has a depth difference of &lgr;/6 between the land track and the groove track.
FIG. 3
illustrates an example of a disc having the above-described L/G track structure. Referring to
FIG. 3
, the track protruded in the incident direction of the optical beam from the optical pickup
102
is defined as a groove track
2
, and the track arranged to alternate with the groove track and depressed from the incident optical beam is defined as a land track
3
. Accordingly, there is a predetermined height difference d between the groove track
2
and the land track
3
. The track pitch (TP) is different according to the kind of disc, but is commonly 1 &mgr;m or less.
As shown in
FIG. 4
, each track is composed of a plurality of sectors which are a data region, and a header region which includes sector position information and control information and which is positioned between the respective sectors. The header region is pre-formatted, and thus the tracking control can be effected in a blank disc where no information signal is recorded.
The header region is a region where data cannot be recorded, is used for obtaining various kinds of information for performing the recording and reproduction, and is generally predetermined by a disc manufacturer.
The header region is briefly classified into two kinds. As shown in
FIG. 4
, one is a header region
8
positioned between sectors in the same track (hereinafter referred to as ‘header region within a track’), and the other is a header region
9
positioned between the last sector
4
of the land track and the first sector
5
of the groove track (hereinafter referred to as ‘header region between tracks’). Accordingly, the opt
Kim Kyung Soo
Park Sang On
Park You Jae
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