Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Description
INFORMATION STORAGE MEDIUM AND METHOD
AND APPARATUS OF RECORDING AND/OR RE-
PRODUCING DATA ON AND/OR FROM THE SAME
Technical Field
[1] The present invention relates to an optical information storage medium on
which
trying polarity data corresponding to the form of pits is recorded, and a
method and
apparatus of recording and/or reprodu~ng data on and/or from the optical
information
storage medium.
Background Art
[2] General optical disks, which are optical information storage media, are
classified
as mmp~t disks (CDs) or digital versatile disks (DVDs) wording to their in-
formation storage cap~aty. The optical disks may also be classified as mini
disks
(MDs) with diameters of 65mm or less. Furthermore, disks having a recording
cap~ity
of 20GB or greater are under development.
[3] The optical disks may be further classified as read-only disks or
rewritable disks.
Examples of the read-only disks are CD-ROM (read only memory) and DVD-ROM.
Examples of rewritable disks are CD ~ R/RW, DVD ~ R/RW, and DVD-RAM
(random mess memory). CD-R and DVD-R can perform recording only once, CD-
RW and DVD-RW can perform recording and/or reproduction about 1000 times, and
DVD-RAM can perform recording and/or reproduction several hundreds of
thousands
of times.
[4] In general, data is recorded as pits on reproduction-only disks or read-
only disks.
Since rewritable disks are coated with a phase changing material, data is
recorded
thereon aoo~rding to a phase change.
[5] In an apparatus for recording and/or reproducing data on and/or from an
optical
disc, a pickup aaurately follows a track on which user data has been recorded
and
receives a laser beam reflected from the try, thereby reading the user data. A
signal
used when the pickup follows the track is referred to as a tracking signal.
The trying
signal is obtained from a photo diode having a plurality of receiving
portions, which
receive a laser beam and adds or subtracts signals obtained from light
received by the
individual receiving portions. The tracking signal is shaped in an S-letter
curve in
which the left and right polarities are opposite to each other around its
center.
[6] The tr~lking signal has different polarities depending on the type of
optical disk,
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that is, the physical char~teristics of a recording layer, for example, the
physical shape
of a pit, the physical shape of a track, and the like. For example, FIGS. lA
and 1B
show groove trues G and land trues L arranged in opposite ways. In FIG. lA, a
trying signal has a polarity that changes from (+) to ( - ). In FIG. 1B, the
tracking
signal has a polarity that changes from ( - ) to (+). As described above, the
polarity of a
trying signal is classified as a polarity changing from ( - ) to (+) or a
polarity
changing from (+) to ( - ). A trying signal is differently processed depending
on the
polarity of the tracking signal. Hence, if the polarity of a tracking signal
is wrongly
recognized, data may not be properly reprod~ed. Accordingly, when an optical
disk is
loaded, a conventional recording and/or reprodu~ng apparatus recognizes the
polarity
of a tracking signal through trial and error and then follows a try on which
user data
has been recorded, based on the information about the recognized polarity. In
this way,
the user data is read from the optical disk.
Disclosure of Invention
Technical Problem
[7] Thus, the conventional reprodu~ng apparatus spends some time obtaining in-
formation about the polarity of a tracking signal before reading out user
data. This
impedes immediate reprod~tion of user data.
[8] The polarity of a trying signal can be changed by the physical shape of a
pit. The
physical shape of a pit may be different depending on the type of disk.
Fbwever, in the
related art, extra information about the polarity of a trying signal depending
on the
physical shape of a pit is not recorded on a disk, so that the reliability of
data recording
and/or reproduction is degraded. Also, the conventional reprodu~ng apparatus
spends
some time obtaining information about the polarity of a trying signal through
trial
and error, delaying recording and/or reprod~tion.
Technical Solution
[9] The present invention provides an optical information storage medium on
which
information about a tracking polarity depending on a pit shape, particularly,
in-
formation about a push-pull polarity, has been recorded, and a method of
recording
and/or reproducing data on and/or from the optical information storage medium.
[10] Am~rding to an aspect of the present invention, there is provided an
information
storage medium having at least one information storage layer, wherein data is
recorded
in the form of protruding or indented pits in the entire or partial area of
the information
storage medium, and information regarding the protruding or indented pits is
recorded.
[11] Am~rding to an aspect of the present invention, the information regarding
the
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protruding or indented pits is push-pull polarity information.
[12] Am~rding to an aspect of the present invention, the information regarding
the
protruding or indented pits is recorded in or in front of a frame sync.
[13] Am~rding to an aspect of the present invention, the information storage
medium
includes a burst cutting area (BCA) and a lead-in area, one of which stores
the in-
formation regarding the protruding or indented pits.
[14] Am~rding to an aspect of the present invention, the protruding or
indented pits
may be wobbling pits.
[15] Am~rding to an aspect of the present invention, data is decoded by
performing an
exclusive OR operation with respect to the push-pull polarity information and
data
reproduced from the protruding or indented pits.
[16] Am~rding to another aspect of the present invention, there is provided a
method of
recording data on and/or reproducing data from an information storage medium
having
at least one information storage layer, the method including recording data in
the form
of protruding or indented pits in the entire or partial area of the
information storage
medium and recording information regarding the protruding or indented pits.
[17] This method further includes reproducing the push-pull polarity
information and
recording data on or reprodu~ng data from the information storage medium by
performing trying on the basis of the reproduced push-pull polarity
information.
[18] Additional aspects and/or advantages of the invention will be set forth
in part in the
description which follows and, in part, will be obvious from the description,
or may be
learned by pr~tice of the invention.
Advantageous Effects
[19] In an information storage medium wording to the present invention, trying
polarity information (i.e., push-pull polarity information) with respect to
protruding
pits and indented pits is recorded so that data can be reliably recorded or
reproduced
without trials and errors for obtaining trying polarity information. Also, if
data is
recorded in the form of pits, e~h of the pits may have various shapes, like,
indented or
protruding pits.
Description of Drawings
[20] The above and/or other features and advantages of the present invention
will
become more apparent by describing in detail exemplary embodiments thereof
with
reference to the attached drawings in which:
[21] FIGS. lA and 1B show different trying polarities depending on a
configuration
of groove trues and land trades;
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[22] FIG. 2A shows protruding pits formed on a substrate of an information
storage
medium aoo~rding to an embodiment the present invention;
[23] FIG. 2B shows indented pits formed on the substrate of the information
storage
medium aoo~rding to an embodiment the present invention;
[24] FIG. 3A is a graph showing the amplitudes of a differential phase
detection (DPD)
signal and a radio frequency (RF) signal versus time in an information storage
medium
on which data is formed as protruding pits;
[25] FIG. 3B is a graph showing the amplitudes of a DPD signal and an RF
signal
versus time in an information storage medium on which data is formed as
indented
pits;
[26] FIG. 4A is a graph showing a push-pull signal versus time in an
information
storage medium on which data is formed as protruding pits;
[27] FIG. 4B is a graph showing a push-pull signal versus time in an
information
storage medium on which data is formed as indented pits;
[28] FIG. 5 shows an example in which tracking polarity data is recorded in a
sync
pattern on an information storage medium ~rording to an embodiment of the
present
invention;
[29] FIGS. 6A and 6B show different examples of the location of the
information
storage medium aoo~rding to an embodiment of the present invention where
trying
polarity information has been recorded in a specafic pattern;
[30] FIGS. 7A and 7B show different layouts of an information storage medium
wording to another embodiment of the present invention;
[31] FIG. 8A schematically shows a structure of an information area of a
recordable in-
formation storage medium;
[32] FIG. 8B schematically shows a structure of an information area of a
reproduction-
only information storage medium;
[33] FIG. 9A shows a straight array of pits, and FIG. 9B shows a wobbling
array of pits;
[3~] FIG. 10 shows an example in which trying polarity information has been
recorded on an information storage medium wording to another embodiment of the
present invention;
[35] FIGS. 11A and 11B are views illustrating a decoding method based on an
exclusive OR (XOR) operation of trying polarity data and data that is detected
from
a data frame in the information storage medium girding to another embodiment
of
the present invention;
[36] FIG. 12 is a flowchart illustrating a data recording and/or reproducing
method
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wording to another embodiment of the present invention ; and
[37] FIG. 13 schematically illustrates an apparatus for recording data in
and/or re-
producing data from an information storage medium wording to the present
invention.
Mode for Invention
[38] Reference will now be made in detail to the embodiments of the present
invention,
examples of which are illustrated in the ~ompanying drawings, wherein like
reference numerals refer to the like elements throughout. The embodiments are
described below to explain the present invention by referring to the figures.
[39] As shown in FIG. 2A, in an optical information storage medium wording to
an
embodiment of the present invention, data is recorded as protruding pits 10 on
a
substrate 5. Alternatively, as shown in FIG. 2B, data is recorded as indented
pits 13 on
the substrate 5. Information about the protruding pits 10 or the indented pits
13 is
recorded in the optical information storage medium
[40] The information about the protruding or indented pits 10 or 13 may be
tracking
polarity information.
[41] When data has been recorded in the form of the protruding pits 10, a
tracking
signal may have a polarity that changes from (+) to ( - ). When data has been
recorded
in the form of the indented pits 13, a trying signal may have a polarity that
changes
from ( - ) to (+). As described above, because the polarity of a tracking
signal varies
depending on the shape of a pit, the trying signal must be performed
differently
depending on the pit shape so that data can be normally recorded or
reproduced.
[42] The conditions and results of a simulation performed to ascertain the
char
teristics of a tracking signal are shown in Table 1.
[43] [Table 1]
[44]
LD wavelength ( ~, ) 400nm
Numerical aperture of objective 0.85
lens
Groove structure Track pitch: 0.32 ~, m
Length of minimum mark 0.149 ~,~ m
Mark width 0.15 ~, m
Modulation technique RLL (1,7)
[45] In Table 1, an RLL modulation technique is based on how many bits '0'
exist
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between two bits '1'. RLL (m,k) represents that at least m bits '0' exist
between two bits
'1' and at most k bits '0' exists therebetween. For example, RLL (1, 7)
represents that at
least one bit '0' exists between two bits ' 1' and at most 7 bits '0' exist
therebetween.
Am~rding to the RLL (m, k) modulation technique, when m is 1, data ' 1010101'
is
recorded, and a pit with a 2T length exists between two bits '1'. When m is 7,
data
'10000000100000001' is recorded, and a pit with an 8T length exists between
two bits
' 1'. Here, T denotes the length of a minimum mark, that is, a minimum pit.
Hence, in
the RLL (1,7) modulation method, data is recorded in the form of pits ranging
in
length from 2T to 8T and spies.
[46] FIG. 3A shows a radio frequency (RF) signal and a differential phase
detection
(DPD) signal when data has been recorded in the form of the protruding pits
10. FIG.
3B shows an RF signal and a DPD signal when data has been recorded in the form
of
the indented pits 13. Referring to FIGS. 3A and 3B, the DPD signal does not
depend
on the shape of a pit.
[47] FIG. 4A shows a push-pull signal when data has been recorded in the form
of the
protruding pits 10, and FIG. 4B shows a push-pull signal when data has been
recorded
in the form of the indented pits 13. Referring to FIGS. 4A and 4B, the push-
pull signal
depends on the shape of a pit. Hence, if data is reproduced or tracked using
the push-
pull signal, information about a tracking polarity depending on a pit shape
needs to be
recorded. Am~rdingly, the information about the tracking polarity may be
information
about the polarity of a push-pull signal.
[48] When recording information about a trying polarity, as shown in FIG. 5,
an
optical information storage medium wording to an embodiment of the present inv
ention includes a plurality of data frames 15, and information about a trying
polarity,
that is, push-pull polarity information. The push-pull polarity information
can be
recorded in a sync pattern on a frame sync 14 included in front of an area
including a
predetermined number of data frames 15. The sync pattern may be a pattern not
used
as a user data pattern or a pattern of specafic bits. An example of the sync
pattern is
shown in FIG. 5.
[49] For example, the sync pattern can be formed of a repetition of identical
data to
represent tracking polarity information. If values '1' are read out
consecutively, this
means that data is recorded in the form of protruding pits. If values '0' are
read out con-
secutively, this means that data is recorded in the form of indented pits.
[50] Alternatively, tracking polarity information, that is, push-pull polarity
information,
may be recorded in a sync pattern of a specific pattern. For example, as shown
in FIG.
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6A, data '010' is recorded in the frame sync 14 and represents a polarity
changing from
(+) to ( - ). In this case, if data ' 101' is reproduced after trying, the
polarity of a
trying signal is processed conversely so that data can be properly reproduced.
In
FIG. 6A, the trying polarity information has been recorded in the frame sync
14.
Fbwever, as shown in FIG. 6B, the tracking polarity information may be
recorded in a
predetermined area 12 in front of the frame sync 14. As described above, the
tracking
polarity information may be recorded in a part of the frame sync 14 or an area
other
than the frame sync 14.
[51] FIG. 7A and 7B show different layouts of an information storage medium
wording to another embodiment of the present invention. This information
storage
medium includes a clamping area C, a burst cutting area (BCA) area B, a lead-
in area
LI, a user data area U, and a lead-out area LO. The clamping area C denotes an
area
which is pressed down by a clamping apparatus for clamping a disc.
[52] Tracking polarity information may be recorded in the BCA area B. Unique
in-
formation about a disc, such as, a serial number, a manufactured
day/month/year, and
the like, may also be recorded in the BCA area B. In FIG. 7A, the BCA area B
is
located between the clamping area C and the lead-in area LI. I~wever, as shown
in
FIG. 7B, the BCA area B may be located in front of the clamping area C.
[53] When tracking polarity information is recorded in the BCA area B, it can
be read
out before a disc is tried after the disc is loaded on a drive and foazsed.
Thus, a
trying servo can be efficiently implemented.
[54] The trying polarity information may also be recorded in the lead-in area
LI
instead of the BCA area B.
[55] FIG. 8A shows a layout of a remrdable information storage medium. Data
can be
recorded in the form of pits in a part of the remrdable information storage
medium, for
example, in a lead-in area or a lead-out area. Information about the shapes of
the pits,
that is, tracking polarity information, can be recorded in the lead-in area,
preferably, in
a disc related information area.
[56] FIG. 8B shows a layout of a reproduction-only information storage medium.
The
trying polarity information can be recorded in a disc related information area
included in a lead-in area. The tracking polarity information includes push-
pull
polarity information.
[57] If data is recorded in the form of pits, the pits may be arrayed either
in a straight
line as shown in FIG. 9A or in a wobbly line as shown in FIG. 9B. When data
has been
recorded in the form of a straight line of pits, the data recorded in the pits
is
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reproduced using a sum channel, and trying can be controlled using DPD or the
push-pull technique. If tracking is controlled using the push-pull technique,
in-
formation about a tradking polarity, that is, push-pull polarity information,
is required.
[58] When data has been recorded in the form of a wobbly line of pits
(hereinafter,
referred to as wobbling pits), additional information can be recorded in the
wobbles
themselves. The data recorded in the wobbling pits is reproduced using a sum
channel,
and the additional information recorded in the wobbles can be reproduced using
a
push-pull channel.
[59] Wobbling pits can be arrayed in a single pattern, which is composed of
pits each
having identical lengths and spaces. In the single pattern of pits, the pits
have no data,
and instead the wobble may have data. In this case, a push-pull channel may be
used as
a channel for reproducing data stored in the wobbling pits.
[60] When data is recorded in the form of wobbling pits, it can be recorded
using
various modulation techniques. For example, data can be recorded using at
least one of
a phase modulation technique, a frequency modulation technique, and an
amplitude
modulation technique.
[61] Referring to FIG. 10, in an information storage medium arxording to
another
embodiment of the present invention, tradking polarity information is recorded
in an
area in front of a predetermined data frame, and although data is recorded in
different
forms, the data in different forms is decoded into identical data by
performing an
exclusive OR (XOR) operation with respect to the tr~king polarity information
and
data read out with the tr~king polarity information. The tr~king polarity
information
may be recorded in a frame sync.
[62] A method of decoding data using an XOR operation when the data has been
recorded in the forms of protruding pits or indented pits will now be
described. When
data recorded in the form of protruding pits is tr~lked, tradking polarity
information is
read as, for example, '0', and data is read as, for example, '11001...'. When
the same
data has been recorded in the form of indented pits, tr~king polarity
information is
read as, for example, ' 1', and data is read as, for example, '00110. . .'.
[63] Referring to FIG. 11A, if tr~king polarity information regarding indented
pits is
recorded as data '0', and data detected from an n-th data frame is ' 11001. .
.', the
tr~king polarity data and the data detected from the n-th data frame undergo
an XOR
operation to obtain decoded data ' 11001. . .'.
[64] Referring to FIG. 11B, if tr~king polarity information regarding
protruding pits is
recorded as data ' 1', and data detected from an n-th data frame is '00110. .
.', the
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trying polarity data and the data detected from the n-th data frame undergo an
XOR
operation to obtain decoded data ' 11001. . .'.
[65] As described above, since data is decoded using an XOR operation with
respect to
trying polarity data and data reproduced from pits, data can be properly
reproduced
and restored regardless of whether the pits are protruding pits or indented
pits. Also,
decoded data can be obtained without extra change in a controlling operation.
[66] Furthermore, data read out by using tracking polarity information, that
is, push-pull
polarity information, as a selection signal can be either directly output as
decoded data
or output as decoded data after the polarity of the data is reversed. In other
words, if
trying polarity information is recorded in a predetermined pattern, and read-
out
trying polarity information is the same as the predetermined pattern, data is
directly
decoded. Fbwever, if tracking polarity information is recorded in a
predetermined
pattern, and read-out tracking polarity information is different from the
predetermined
pattern, data is decoded after its polarity is reversed.
[67] The information storage medium arxording to the present invention is
applicable to
multi-layered information storage media with at least two information storage
layers as
well as to single-layered information storage media.
[68] FIG. 12 is a flowchart illustrating a data recording and/or reproducing
method
wording to an embodiment of the present invention. Referring to FIG. 12, in
operation 50, an information storage medium is loaded on a disk drive. In
operation
55, an optical pickup included in the disk drive reads trying polarity
information,
that is, push-pull polarity information, from the loaded information storage
medium.
The trying polarity information is recorded as in the embodiments described
above
and used as a basis on which a tracking signal is detected or data is recorded
and/or
reproduced.
[69] Because a trying polarity varies depending on the protruding pits 10 of
FIG. 2A
or the indented pits 13 of FIG. 2B, a trying signal is differently processed
aoo~rding
to trying polarity information. If tracking polarity information is recorded
in the
BCA area B, an information storage medium is first loaded on a disk drive, and
then
foazsing control is Thieved, and the trying polarity information is read from
the
BCA area B before data is read from the loaded information storage medium.
Thus,
trying control and information reproduction are reliable.
[70] In operation 60, the disk drive records data on or reproduces data from a
data area
by performing tracking control without trials and errors on the basis of the
reproduced
trying polarity information, that is, push-pull polarity information. In other
words,
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the optical pickup provides the reproduced trying polarity information to the
disk
drive, and the disk drive controls the optical pickup on the basis of the
received in-
formation so that data is smoothly recorded on or reproduced from the
information
storage medium.
[71] Data can be decoded by performing an XOR operation with respect to
tracking
polarity data and data reproduced from pits. Thus, data can be decoded
regardless of a
trying polarity.
[72] Data reproduced on the basis of the tracking polarity information may be
either
directly output as decoded data or output as decoded data after its polarity
is reversed.
In other words, if trying polarity information is recorded in a predetermined
pattern,
and read-out tracking polarity information is the same as the predetermined
pattern,
data is directly decoded. On the other hand, if trying polarity information is
recorded
in a predetermined pattern, and read-out tracking polarity information is
different from
the predetermined pattern, data is decoded after its polarity is reversed.
[73] FIG. 13 schematically illustrates an apparatus for recording data in
and/or re-
producing data from an information storage medium wording to the present
invention. The apparatus includes a pinup 50, a recording/reproducing signal
processor 60, and a controller 70. More specifically, the pickup 50 includes a
laser
diode 51 for radiating light, a collimating lens 52 for collimating the light
emitted by
the laser diode 51, a beam sputter 54 for changing a path of incident light,
and an
objective lens 56 for foazsing light passed through the beam sputter 54 on an
in-
formation storage medium D.
[74] Light reflected by the information storage medium D is reflected by the
beam
sputter 54 and received by a photodetector, for example, a 4-divisional
photodetector
57. The light incident upon the 4-divisional photodetector 57 is converted
into an
electrical signal while passing through an operational circuit 58. An RF
signal, that is,
a sum signal is output via a first channel Chl and a differential signal used
in a push-
pull technique via a second channel Ch 2.
[75] When the information storage medium D is loaded, the controller 70
controls the
pickup 50 to project a beam onto the information storage medium D and reads
out a
signal into which a beam reflected by the information storage medium D is
converted
by the signal processor 60. More specifically, the beam reflected by the
information
storage medium D is applied to the photodetector 57 via the objective lens 56
and the
beam sputter 54. The beam incident upon the photodetector 57 is converted into
an
electrical signal by the operational circuit 58, and the electrical signal is
output as an
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RF signal.
[76] The signal processor 60 processes a data signal girding to trying
polarity in-
formation read out from the information storage medium D. T he controller 70
controls
the pinup 50 based on the data signal processed by the signal processor 60.
