Dynamic information storage or retrieval – Control of storage or retrieval operation by a control... – Mechanism control by the control signal
Reexamination Certificate
1998-11-05
2001-02-20
Huber, Paul W. (Department: 2753)
Dynamic information storage or retrieval
Control of storage or retrieval operation by a control...
Mechanism control by the control signal
C369S124140
Reexamination Certificate
active
06192015
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method and apparatus for performing a recording/reproduction of an information on/from a recording medium having recording tracks each defined by wobbled grooves.
2. Description of the Related Art
Nowadays, a need of a larger capacity has been increased in an optical recording/reproducing field or an opto-magnetic recording/reproducing field. Accordingly, in a recording medium such as a DVD-RAM (digital versatile disc-random access memory) and so on, there has been suggested a so-called land/groove recording system having an information recorded on both of land and groove tracks.
For example, a DVD-RAM as shown in
FIG. 1
is provided with wobbled groove tracks
10
and land tracks wobbled alternately with the groove tracks
10
in the width direction of the groove tracks
10
. The groove and land tracks
10
and
12
are used as recording regions. A certain period of wobbling signals are included in a wobbled portion
14
of each of the groove and land tracks
10
and
12
, hereinafter referred to as “wobbled part”, that is, in each side of the land and groove tracks
10
and
12
. A recording/reproducing apparatus for an optical recording medium generates a rotation control information about the DVD-RAM and a recording clock with the aid of the wobbling signals. Also, each of the land and groove tracks
10
and
12
is alternated with a identification (ID) region consisting of a pre-pit train
16
. The pre-pit train
16
includes an address information for indicating the physical position of the groove and land tracks
10
and
12
. The physical positions of all the groove and land tracks
10
and
12
are indicated with such ID regions, thereby recording an information on all the groove and land tracks
10
and
12
. As a result, a large amount of information can be recorded in the DVD-RAM.
In the optical recording medium of such a land/groove recording system, wobbling signals detected from each of the adjacent groove and land tracks
10
and
12
have a contrary phase to each other. This is caused by a physical shape and an optical characteristic in the groove and land tracks
10
and
12
. Thus, when a laser light beam is transferred from the groove track
10
to the land track
12
or vice versa, a phase of the wobbling signal is inverted. For example, in a single-spiral type of recording medium, the wobbled groove and land tracks
10
and
12
are alternated every once rotation, so that a phase of the wobbling signal is inverted whenever the recording medium is rotated once. More specifically, an electrical signal as shown in
FIG. 2A
is detected from the groove track
10
while an electrical signal as shown in
FIG. 2B
is detected from the land track
12
. Referring to
FIGS. 2A and 2B
, it is to be noted that first and second wobbling signal
13
A and
13
B detected from the groove track
10
are phases contrary to third and fourth wobbling signals
13
C and
13
D detected from the land track
12
, respectively. When a light beam enters the land track
12
from the groove track
10
, the fourth wobbling signal
13
D in
FIG. 2B
having a phase contrary to the first wobbling signal
13
A in
FIG. 2A
emerges at the rear portion of the first wobbling signal
13
A. On the other hand, when a light beam enters the groove track
12
from the land track
12
, the second wobbling signal
13
B in
FIG. 2A
having a phase contrary to the third wobbling signal
13
C in
FIG. 2B
emerges at the rear portion of the third wobbling signal
13
C. In other words, in the single-spiral type of optical recording medium, the land and groove tracks are alternated or replaced every once rotation, so that a phase of the wobbling signal becomes inconsistent at their crossing position.
Meanwhile, a general recording clock is generated by slicing the wobbling signal
13
into a zero-crossing level to generate a wobbling pulse signal having a rectangular wave shape and then applying the wobbling pulse signal to a phase synchronizing loop. The recording clock generated in this manner has a different phase whenever a light beam is transferred from the groove track
10
to the land tracks
12
or vice versa. This results from a phase of the wobbling signal being inverted whenever a light beam is transferred from the groove track
10
to the land track
12
or vice versa. A rotation control information produced based on the recording clock also becomes different whenever a light beam is transferred from the groove track
10
to the land track
12
or vice versa. Accordingly, a recording/reproducing apparatus for the optical recording medium must invert the polarity of the wobbling signal each time a light beam is transferred from the groove track
10
to the land track
12
or vice versa so as to perform the generation of recording clock and the rotation control accurately.
In order to switch the polarity of the wobbling signal, the recording/reproducing apparatus must accurately identify whether a track being currently driven (i.e., recorded or reproduced) is a land track or a groove track. If such a land/groove identification is accurately performed, then it is impossible for the recording/reproducing apparatus to do the clock generation and the rotation control smoothly. In addition, a tracking control of push-pull system also requires the land/groove identification. This results from the polarity of the tracking error signal being inverted each time a light beam is transferred from the groove track to the land track or vice versa. Likewise, when the land/groove identification is accurately performed, the tracking control of push-pull system also is not done smoothly.
The above-mentioned land/groove identification is usually dependent upon a push-pull signal detected from the identification (ID) region. However, the push-pull signal may be not at all detected or may be inaccurately detected from the optical recording medium. For example, since a header region is not read in the case of performing an additional operation such as a track search and so on, the push-pull signal is not at all detected. Further, the push-pull signal is not detected accurately in the case of having a large tracking offset. It becomes difficult to do the land/groove identification when the push-pull signal at the header region as mentioned above is not detected accurately.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a driving method and apparatus for a recording medium that can drive a recording medium of land/groove recording system using a wobbling signal without a land/groove identification information.
Further object of the present invention is to provide a recording/reproducing method and apparatus for a recording medium that can perform a recording/reproducing of a recording medium of land/groove recording system by obtaining a land/groove identification in the recording medium with a wobbling signal.
In order to achieve these and other objects of the invention, a recording/reproducing method for a recording medium according to one aspect of the present invention includes the steps of detecting a wobbling signal from a recording medium having wobbled land and groove tracks; multiplying a frequency of the wobbling signal; generating a predetermined reference signal based on the multiplied wobble signal; and responding to the reference signal to perform a recording/reproduction of the recording medium. The recording/reproducing method further includes the steps of detecting a playing speed error of the land and groove tracks from the reference signal; and controlling a playing speed of the land and groove tracks in accordance with the playing speed error. The recording/reproduction of the recording medium. The recording/reproducing method further includes the steps of detecting whether any one of the land and groove tracks is being accessed on a basis of a phase relationship of the reference signal with the wobbling signal; and selectively inverting the polarity of a tracking error signa
Huber Paul W.
LG Electronics Inc.
LandOfFree
Method and apparatus for recording and reproducing recording... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for recording and reproducing recording..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for recording and reproducing recording... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2602789