Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
2000-07-07
2004-06-08
Young, W. R. (Department: 2652)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
C369S047220
Reexamination Certificate
active
06747932
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus and method for detecting non-recording regions of an optical recording medium, and more particularly, to an apparatus and method for detecting non-recording regions of an optical recording medium for recording data or reproducing the recorded data by detecting header regions of the optical recording medium.
2. Description of the Background Art
Generally, an optical recording/reproducing apparatus records or reproduces data on an optical recording medium such as a CD (Compact Disc), DVD-RAM (Digital Versatile Disc-Random Access Memory), etc. The above-mentioned optical recording medium has a track structure consisting of a land and groove. Particularly, a rewritable optical recording medium such as the DVD-RAM records data signals on the land and groove, respectively, in order to increase data recording density. To record data on the land and groove, the optical recording/reproducing apparatus must reduce the size of a laser beam spot for recording and reproducing data by decreasing the wavelength of a laser light outputted from an optical pickup and increasing the numerical aperture of an objective lens of the optical pickup.
FIG. 1
is a block diagram of a general optical recording/reproducing apparatus, wherein an optical recording medium for recording data on a land and groove is mounted on a drive of the above optical recording/reproducing apparatus.
To record or reproduce data on the optical recording medium, optical pickup
102
is operated by control of servo control unit
106
through focus servo driving unit
107
and tracking servo driving unit
108
, and accordingly outputs laser beams onto a signal recording surface of the optical recording medium
101
on which data is recorded. When the light reflected from the signal recording surface of the optical recording medium is incident on the optical pickup again, the optical detector installed in the optical pickup outputs electric signals to the RF and servo error generating unit
104
.
RF and servo error generating unit
104
outputs focus error signals, tracking error signals, and RF signals (lead channel
1
signals) upon receipt of the electrical signals. Herein, the focus error signals (FE) and the tracking error signals (TF) (lead channel
2
signal) are generated from the electric signals outputted from the optical detector comprised of a plurality of optical detection devices.
The lead channel signals
1
outputted from RF and servo error generating unit
104
are outputted to decoder
105
, and the FE signals and TE signals are outputted to servo control unit
106
. Namely, decoder
105
restores the RF signals to the original data when it reproduces the data recorded on the optical recording medium.
Encoder
103
receives data to be recorded on the optical recording medium. That is, encoder
103
encodes the data to be recorded using recording pulses appropriate to the type of optical recording medium
101
, and thereafter records the encoded data on optical recording medium
101
through optical pickup
102
.
Meanwhile, the above-described optical recording/reproducing apparatus can be connected to a host such as a PC. In the optical recording/reproducing apparatus connected to the host, when a recording/reproducing command transmitted from the host through interface
110
is inputted to microcomputer
111
, the data to be recorded on optical recording medium
101
is transmitted to encoder
103
to thus be recorded on optical recording medium
101
by control of microcomputer
111
, and the data outputted from optical recording medium
101
is transmitted from decoder
105
, for thereby reproducing the data recorded on optical recording medium
101
.
Servo control unit
106
outputs control signals to focus servo driving unit
107
and tracking servo driving unit
108
, respectively, upon receipt of the focus error signals (FE) and tracking error signals (TE). Focus servo driving unit
107
drives a focus actuator in optical pickup
102
to move optical pickup
102
upwardly and downwardly, and makes beams outputted from optical pickup
102
to follow tracks of optical recording medium
101
as optical recording medium
101
is rotated and at the same time moved upwardly and downwardly, being focused on the track of optical recording medium
101
. In addition, tracking servo driving unit
108
drives a tracking actuator in optical pickup
102
to move the objective lens of optical pickup
102
in the radial direction, thereby correcting the position of the beams and following the tracks.
Meanwhile, in the case of optical recording medium
101
such as DVD-RAM which is directly delivered from its manufacturer and has no information recorded, the optical recording/reproducing apparatus cannot record any data on optical recording medium
101
because optical pickup
102
cannot access optical recording medium
101
. Therefore, in order to record data on optical recording medium
101
, optical recording medium
101
must have land and groove tracks. On optical recording medium
101
having the above tracks, control information for sector addressing, random access, and rotation control is recorded along with the tracks on which data is recorded, being separated from the above-mentioned data to be recorded, thus making it possible to control the tracking of optical recording medium
101
having no recorded data thereon. Namely, the above-mentioned control information can be recorded by pre-formatting header regions on the starting position of each sector or by forming wobble along with the tracks.
Here, the above-mentioned wobble is information recorded on the optical recording medium by modulating certain clocks, including the information on the corresponding position and rotational speed of the optical recording medium, which is analyzed by optical power detected by a laser diode of the optical pickup.
FIG.
2
(
a
) is a view illustrating a header region pre-formatted on the starting position of each sector of the optical recording medium, said header region having four header fields (header
1
field~header
4
field).
The header
1
and
2
fields and the header
3
and
4
fields are arranged in a staggered fashion with each other from the center of the tracks. The phase of the header
1
and
2
fields is opposite to that of the header
3
and
4
fields, and also the phase of tracking error signals detected from the header
1
and
2
fields is opposite to that of tracking error signals detected from the header
3
and
4
fields. The track interface of regions whose data is recorded on the optical recording medium is, as illustrated in FIG.
2
(
a
), formed in a wobble shape.
In the structure of the header region of the optical recording medium described above, servo error signals such as tracking error signals and focus error signals are generated. That is, the servo error signals read out from the header regions are distorted according to the structure of the header regions, and it is difficult to control the distorted servo error signals.
Therefore, in the case of optical recording medium such as DVD-RAM, the servo of the optical recording/reproducing apparatus is performed so that the servo error signal is held in the header regions, in order to reduce the influence on the servo error signals according to the header structure. That is, in the header region section, the beams outputted from the optical pickup are made not to deviate from the center of the tracks of the optical recording medium by covering the header regions with header masks and holding the tracking error signals
For this purpose, it must be firstly judged that the information reproduced by the optical recording apparatus belongs to the header regions of the optical recording medium. The header regions are judged by using wobble signals detected from lead channel
2
signals and IP
1
or IP
2
signals. Herein, since the number of wobble signals existing on each sector is always constant, header mask signals are generated by counting th
Battaglia Michael
LG Electronics Inc.
Young W. R.
LandOfFree
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