1. A recordable optical disc (100) comprising: a disc substrate (110); a record track (102) formed on said disc substrate spirally or coaxially around a center of said disc substrate (110); and an emboss pit formed in a predetermined zone on said disc substrate (110) in correlation with predetermined data, which is recorded on said record track in the predetermined zone, said recordable optical disc (100) characterized in that said emboss pit is formed such that said emboss pit does not exist at a boundary between a record mark and a record space of the predetermined data, but within a record mark or a record space of the predetermined data.

2. A recordable optical disc as claimed in Claim 1, wherein said emboss pit is formed at a position where a length of a record mark of the predetermined data along the record track is equal to or longer than a predetermined length.

3. A recordable optical disc as claimed in Claim 2, wherein a length of said emboss pit is constant regardless of the length of the record mark.

4. A recordable optical disc as claimed in Claim 2, wherein a length of said emboss pit is variable depending upon the length of the record mark.

5. A recordable optical disc as claimed in Claim 1, wherein said emboss pit is formed at a position where a length of a record space of the predetermined data along the record track is equal to or longer than a predetermined length.

6. A recordable optical disc as claimed in Claim 5, wherein a length of said emboss pit is constant regardless of the length of the record space.

7. A recordable optical disc as claimed in Claim 5, wherein a length of said emboss pit is variable depending upon the length of the record space.

8. A recordable optical disc as claimed in Claim 1, wherein a plurality of emboss pits each having a structure same as the emboss pit are formed in the predetermined zone.

9. A recordable optical disc as claimed in Claim 8, wherein a first emboss pit of the emboss pits is formed at a position where a length of a record mark of the predetermined data along the record track is equal to or longer than a predetermined length and a second emboss pit of the emboss pits is formed at a position where a length of a record space of the predetermined data along the record track is equal to or longer than the predetermined length.

10. A recordable optical disc as claimed in Claim 9, wherein a length of said first emboss pit along the record track is variable depending upon the length of the record mark and a length of said second emboss pit along the record track is variable depending upon the length of the record space.

11. A recordable optical disc as claimed in Claim 8, wherein a length of each of the emboss pits along the record track is constant.

12. A recordable optical disc as claimed in Claim 1, wherein the predetermined zone is in a control data zone, and the predetermined data is control data to control a recording and /or reproducing operation of data recorded on said record track in a data record zone, which is different from the predetermined zone and where said emboss pit is not formed.

13. A recordable optical disc as claimed in Claim 12, wherein said control data zone is within a lead in area.

14. A recordable optical disc as claimed in Claim 1, wherein data other than the predetermined data is recorded on said record track in a data record zone, which is different from the predetermined zone and where said emboss pit is not formed.

15. A recordable optical disc as claimed in Claim 1, comprising a record layer, which is formed on said disc substrate and by which data including the predetermined data is recorded on said record track.

16. A recordable optical disc as claimed in Claim 15, wherein said record layer comprises a material capable of a recording operation of write many times type.

17. A recordable optical disc as claimed in Claim 15, wherein and record layer comprises a material capable of a recording operation of write once type.

18. A recordable optical disc as claimed in Claim 15, wherein said record layer comprises a material capable of a recording operation of write limited times type.

19. A recordable optical disc as claimed in Claim 1, further comprising a reflective layer formed on said disc substrate for reflecting a light beam for a recording and/or reproducing operation of data recorded on the record track.

20. A method of recording data on a recordable optical disc (100) comprising: a disc substrate (110); and a record track (102) formed on said disc substrate (110) spirally or coaxially around a center of said disc substrate (110); and an emboss pit formed in a predetermined zone on said disc substrate (110) in correlation with predetermined data, which is recorded on said record track (102) in the predetermined zone, characterized in that said method comprises the steps of: forming the emboss pit on the disc substrate (110) such that said embossed pit does not exist at a boundary between a record mark and a record space of the predetermined data, but within a record mark or a space of the predetermined data; and recording the predetermined data in the predetermined zone.

21. A method as claimed in Claim 20, further comprising a process of recording data other than the predetermined data in a data record zone, which is different from the predetermined zone where said emboss pit is not formed A recordable optical disc (100) is provided with a disc substrate (110); a record track (102) formed on the disc substrate spirally or coaxially around a center of the disc substrate; and an emboss pit formed in a predetermined zone on the disc substrate in correlation with predetermined data, which is recorded on the record track in the predetermined zone.

The present invention relates to a recordable optical disc and a
method of recording data on the recordable optical disc, which can
improve a protection of the recorded data.

There are various types of optical discs because of the
diversification of formats of the CDs (Compact Disc*) and the
introduction of the DVD.
According to the formats of the CDs, there are a read only type
CD-ROM (CD-Read Only) on which data can be read many times but cannot be
written, a write once type CD-R (CD-Recordable) on which data can be read
many times and can be written only once, and a CD-RW (CD Rewritable) on
which data can be read many times and can dp written many timos. Aoeurding
to the formats of the DVDs, there are a read only type DVD-ROM (DVD Road
Only) on which data can be read many times but, cannot be written, a write once
type DVD-R (DVD-Recordable) on which data can be read many rimes and can
be written only once, a ro-recordable type DVD-RW (DVD Ro-recordable) on
winch data can be read many times and can be written for limited times, and a
rewritable type DVD-RAM (DVD Rewiitable) on which data can be read many
time? and can be written re any Limps.
By the way, in a control data zone of the DVD-ROM, information
important only for the D\7>ROM is written. Tn a zone, who.se position is the
same as this control data zone, of the DYD-RW, an unreadable emboss is
formed or buried to thereby disable both of reading and willing in this zone, in
order to prevent the falsification or manipulation of the data. Therefore, the
control data is written on the DYD-RW, in a zone different from that of the
DVD-ROM.
However, if such a probability is considered that important information,
which is common for the DVD-ROM and the DVD-RW and Ls nut desired to be
falsified or manipulated, is commonly written on the DVD-ROM and the
DVD-RW, it will be required or convenient to record such important information
in the same zones on those discs.

it is therefore an object of the present invention io provide a
recordable optical disc and a method of recording data on the recordable
optical disc, which can prevent the data recorded in a predetermined
zone on the recordable optical disc from being falsified,
The above object of the present invention can be achieved by a
recordable optical disc provided with: a disc substrate! a record track
formed on the disc substrate .spirally or coaxially around a center of the
disc substratei and an emboss pit formed in a predetermined zone on the
disc substrate in correlation with pvedetei'mined data, which is recorded
on the record track in the predetermined zone.
According to the recordable optical disc of the prcscni invention,
since the data pattern of the predetermined data is known in advance,
the emboss pit is formed in the predetermined zone in correlation with
the predetermined data to be recorded in the predetermined zone. Then,
the predetermined data is recorded in the predetermined /one where the
emboss pit is formed. On one hand, although time exists the emboss
pit in the predetermined zone, it is possible to normally wrte and read
the predetermined data since the predetermined data is in correlation
with the emboss pit. On the other hand, data other than the
predetermined data cannot be normally written onto or read from the
predetermined zone since such data other than the predetermined data
are not in correlation with the emboss pit. Namely, even if it is
attempted to falsify the predetermined data, a record mark and a record
space of such data other than the predetermined data are probably
influenced by the existence of the emboss pit, which most likely appears
at the boundary between the record mark and the record space and
which significantly drifts the signal level in the middle of the record
mark and/or the record space.
In this manner, by forming the emboss pit, which i > in
correlation with the predetermined data, in the predetermined zone in
advance, the reflection coefficient is intentionally decreased by the
existence of the emboss pit. Therefore, the operation of falsifying the
predetermined data is most likely failed due to the decrease of the
reflection coefficient, while the predetermined data can be normally
written and read against (he decrease of the reflection coefficient.
In one aspect of the recordable optical disc of the present
invention, the emboss pit is formed such that the emboss pit does noi
exist, a! a boundary between a record mark and a record space of the
predetermined data,
According to this aspect, the emboss pit does not exist at the
boundary between the record mark and the record i-paoe of the
predetermined data. Namely, the length of the emboss pit along the
record track is shorter than the length of the record mark or record space
along the record track. Thus, the predetermined data can bo normally
written onto and read from the predetermined zone against the decrease
of the reflection coefficient caused by the emboss pit.
In another aspect of the recordable optical disc of the present
invention, the emboss pit is formed at a position where a lengrh of a
record mark of the predetermined data along the record track is equal to
or longer than a predetermined length.
According to this aspect, since the emboss pit is formed at a
position where the length of the record mark is equal to or longer than a
predetermined length (e.g., ST, 4T or the like, wherein T denotes a base
clock cycle), it is possible to surely prevent the predetermined data from
being falsified, by forming the emboss pit having a certain length (.eg,.
•IT. 2T or the like) which is shorter than that of The record mark but is
longer than the base clock cycle.
In this aspect, a length of the emboss pit. may be constant,
regardless of the length of the record mark.
By constructing in this manner, it is possible to easily form the
emboss pit.
Alternatively in ibis aspect, a length of the emboss pit may be
variable depending upon the length of the record mark.
By const fueling in this manner, it is possible to koi'p a remain
margin of the emboss pit with rospuct to the edges of the record mark,
the length of which is variable. Namely, the emboss pit is made long if
the record mark is bus:., while the emboss pit is :rade shore if the record
mark is short, so chat an appropriate margin of the emboss pit is kept.
In another aspect of the recordable optical disc of the present
invention, the emboss pit is formed at a position where a length of a
record space of the predetermined data along the record track is equal to
or longer than a predetermined length.
According- to this aspect, since the emboss pit i& formed at a
position where the length of the record space is equal to or longer than a
predetermined length (e.g., 8T, 4T or the like), it is possible to surely
prevent the predetermined dm,"; from being falsified, by forming the
emboss pit having a certain length (e.g.. 4T, 2T or the like) which is
shorter than that of the record space bin is longer tru.n the base clock
cycle.
In this aspect, a length of the emboss pit may be constant
regardless of the length of the record space.
By constructing in this manner, it is possible to easily form the
emboss pit.
Alternatively in this aspect, a length of the emboss pit may be
variable depending upon the length of the record space,
By constructing in this manner, it is possible to keep a certain
margin of the emboss pit with respect to the edges of the record. ?pace,
the length of which is variable. Namely, the emboss pit i ¦¦ i mde 'ong if
the record space is long, while the emboss pit is made short if the -coord
space is short, so that an appropriate margin of the emboss pit is kept.
In another aspect of the recordable optical disc of i he present.
invention, a plurality of emboss pits each having a structure same as the
emboss pit are formed in the predetermined zone.
According to this aspect, since a plurality of emboss pits are
formed in the predetermined zone, it is possible to more reliably prevent
the predetermined data from being falsified.
In this aspect, a first emboss pit of the emboss pits may be
formed at a position where a length of a record mark cf the
predetermined data along the record track is equal to or longer than a
predetermined length and a second emboss pit of the emboss pits may be
formed at a position where a length of a record space of the
predetermined data along the record track is equal to or longer than the
predetermined length
By-constructing in this maimer, since the first emboss pit is
formed at a position where the length of the record mark is equal to or
longer than a predetermined length (e.g., 8T, 4T or the like) and since
the second emboss pit is formed at a position where the length of the
record space is equal to or longer than a predetermined length (e.g., ST,
4T or the like), it is possible to surely prevent the predetermined data
from being falsified, by forming the emboss pit having a certain length
(e.g.. 4T. 2T or the like) which is shorter than that of the record mark or
space but is longer than the base clock cycle.
Further in such a structure, a length of the first emboss pit along
the record track may be variable depending upon the length of the record
mark and a length of the second emboss pit along the record track may
be variable depending upon the length of the record space.
By constructing in this manner, it is possible to keep certain
margins of the first and second emboss pits with respect to the edges of
the record mark and space respectively. y.'Ui:.cly :he fuvst emboss pit is
made long if the record mark is Ions, while the first emboss pit is made
short if the record mark is short, so that an appropriate margin of the
first emboss pit is kept, On the other hand, the second emboss pit is
made long if the record space is long, while the second emboss pit is
made short if the record space is short, so that an appropriate margin of
the second emboss pit is kept.
In the aspect in which a plurality of emboss pits are formed in
the predetermined zone, a length of each of the emboss pits along the
record track may be constant.
By constructing in this manner, it is pos.sibie to easily form the
emboss pits.
In another aspect of the recordable optical disc of the present
invention, the predetermined zone is in a control data '/one, and the
predetermined data is control data to control a recording and/or
reproducing operation of data recorded on the record track in a data
record zone, which is different from the predetermined zone and where
the emboss pit is not formed.
According to this aspect, the control data recorded in the control
data zone can be prevented from being falsified. The data such as video
data, audio data or the like, in the data record /one can be recorded
and/or reproduced in accordance with the control data.
In this aspect, the control data zone may be within a lead in area,
By constructing in this manner, the control data in the control
data /one in the lead in area can be prevented from being falsified,
In another aspect of ihe recordable optical disc of the present
invention, data other thrui the predetermined data is recorded on the
record track in a data record zone, which is different from the
predetermined zone and where the- emboss pit is not formed.
According to this aspect, it is possible t.o normally record and
reproduce the data in the data record zone, where the emboss pit is not
formed.
In another aspect of the recordable optical disc of the present
invention, the recordable optical disc is further provided with a record
layer, which is formed on the disc substrate and by which da!a including
the predetermined data is recorded on the record track.
According to this aspect, the data including the predetermined
data such as control data etc., as well as video data, audio data etc., can
be surely recorded on the record track by virtue of the record layer.
In this aspect, the record layer may comprise a maLerial capable
of a recording operation of write many times type,
By constructing in this manner, a write many type optical disc
such as a DVD-RAM or the like can be realized.
Alternatively in this aspect, the record layer may comprise a
material capable of a recording operation of write once type.
By constructing hi this manner, a write once typo optical disc
such as a DVD-I? or tho like can bo realized.
Further alternatively in this aspect, the record layer may
comprise a material capable of a recording operation of write limited
times type.
By constructing in this manner, a write many type optical disc-
such as a DVD-RW or the like can be realized.
In another aspect of the recordable optical disc of the present
invention, the recordable optical disc is further provided with a reflective
layer formed on the disc substrate for reflecting a light beam for a
recording and/or reproducing operation of data recorded on the ;:ecord
track.
According to this aspect., the data including the predetermined
data such as control data etc., as well as video data, audio data etc., can
be surely recorded and/or reproduced on the record track by virtue of th.0
reflective layer, which reflects a laser beam .rcr a recording; -md/or
reproducing operation,
The above object of the present invention can be also achie/ed by
a method of recording data on the above described recordable optical disc
of the present invention (including its various aspects), The method is
provided with: a process of forming rhe emboss pit on the disc substrate;
and a process of recording the predetermined data in the predetermined
zone,
According to the method of the present invention, the emboss pit
is formed in advance in the predetermined zone in correlation with lIio
predetermined data to be recorded in the predetermined /one. Then,
the predetermined data is recorded in the predetermined '/one where the
emboss pit is formed. Therefore, the operation of falsifyirg the
predetermined data is most likely failed due to rhe decrease of the
reflection coefficient caused by the emboss pit, while the predetermined
data can be normally written and read against the decrease of the
reflection coefficient caused by the emboss pit.
In one aspect of the method of the present invention, the method
is further provided with a process of recording data other than the predetermined data in a
data record zone, which is different from the predetermined zone and where the emboss
pit is not formed.
According to this aspect, after the predetermined data is recorded in the
predetermined zone such as a control zone in a lead in area, the data such as video data,
audio data or the like other than the predetermined data is recorded in the data record
zone, by a user at home for example. Accordingly, the data in the data record zone can
be recorded and/or reproduced in accordance with the predetermined data in the
predetermined zone, which is not falsified.
According to the invention there is provided a recordable optical disc (100)
comprising:
a disc substrate (110);
a record track (102) formed on said disc substrate spirally or coaxially around a
center of said disc substrate (110); and
an emboss pit formed in a predetermined zone on said disc substrate (110) in
correlation with predetermined data, which is recorded on said record track in the
predetermined zone, said recordable optical disc (100) characterized in that said emboss
pit is formed such that said emboss pit does not exist at a boundary between a record
mark and a record space of the predetermined data, but within a record mark or a record
space of the predetermined data.
The invention also provides for a method of recording data on a recordable optical
disc (100) comprising: a disc substrate (110); and a record track (102) formed on said
disc substrate (110) spirally or coaxially around a center of said disc substrate (110); and
an emboss pit formed in a predetermined zone on said disc substrate (110) in correlation
with predetermined data, which is recorded on said record track (102) in the
predetermined zone, characterized in that
said method comprises the steps of:
forming the emboss pit on the disc substrate (110) such that said embossed pit
does not exist at a boundary between a record mark and a record space of the
predetermined data, but within a record mark or a space of the predetermined data; and
recording the predetermined data in the predetermined zone.
The nature, utility, and further features of this invention will be more clearly
apparent from the following detailed description with respect to preferred embodiments
of the invention when read in conjunction with the accompanying drawings briefly
described below:
11
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
FIG. 1A is a perspective view of the DVD used in embodiments of the present
invention;
FIG. IB is a magnified partial perspective view of a transparent substrate of the
DVD in FIG. 1A at a portion including record tracks;
FIG. 1C is a partial sectional view of the DVD in FIG. 1A at a portion including
the record tracks;
FIG. ID is a diagram schematically showing a data structure of the DVD used in
the embodiments;
FIG. 2 is a diagram showing a detailed structure of a lead in area shown in FIG.
ID;
FIG. 3A is a diagram showing a basic principle of a recording
method of the embodiments;
FIG, 3B is a magnified partial perspective view of the DVD
showing the basic principle of the recording method of the embodiments;
FIG. 4 is a timing chart in one operational example of the
recording method m a first embodiment;
FIG. 5 is a timing chart in another operational example vhen
falsified data is written in the example of F.10. 1;
FIG. 6 is a timing chart in one operational example o* the
recording method in a second embodiment;
FIG. 7 is a timing chart in another operational example- when
falsified data is written in the example of FIG. 6; and
FIG. 8 is a process chart showing a method of recording data on
the DVD of the embodiment.
BETAdtEI^l^-Se Rrl^OK^^
Referring to the accompanying drawings, embodiments of the
present invention will be now explained.
In FIG, 1A, a DVD 100 is provided with a iransparen.. substrate
110 having a center hole 103 and record tracks 102 spiral or craxial
around the center hole 103. From the inner circumferential side toward
the outer circumferential side on the DVD 100, there are fonned: a
clampiny area CA which is clamped by a clamper when the DVD 100 is
set to an information recording and/'or reproducing apparatus; a record
information area RfA: and an inforniation area I A. In the informal ion
area 1A. there are foimcd a lead in area LI A, a data recordable area DRA
and a lead out area LOA in this order from the inner circumferential side.
The record tracks 102 are formed in the record information area PJA as
well as the information area IA.
As shown in FIG. IB, the record tracks 102 consists oHi) a land
track L comprising a land, which is convex on the transparent substrate
110 and is concave with respect to a laser beam Lft for a reading
operation and/or a writing operation, and (ii) a groove track G comprising
a groove, which is concave on the transparent substrate 110 and is
convex with respect to the laser beam LB, On the land track L, a laud
pre-pit LPP is formed. The groove track G are wobbled at a
predetermined frequency. The land pre-pit LPP and the wobble of the
groove track G are used to define the physical address on the ::ecord
track 102.
On the basis of the information indicated by the land pre-p.it LPP
and the wobble of the groove track G, a position of an optical pickup in
the information recording and/or reproducing apparatus is controlled
with respect to the wobble, so that the operation of recording record data
onto the groove track G (i.e.. a data writing operation) and the operation
of reproducing the record data from the groove track G (i.e., a data
reading operation) are performed. The record data and/or the control
data to control the recording and/or reproducing the record data may he
recorded on the land track L in place of or in addition to the groove rrack
G.
As shown in FIG. lC. on the transparent substrate I 10. a record
layer 111, a light reflective layer 112 and a protection layer I i(J are
laminated. The record layer ill. may comprise a dye e.g., a material
\vhose optical property is changed when a writing laser beam which is
stronger than a reading laser beam is irradiated, in ease of the DVD-R.
Alternatively., the record layer 111 may comprise a phase-change
material e.g., a material whose phase is changed between a crystalloid
phase and an amorphous phase depending upon the irradiation condition
of the laser beam, in case of the DVD-RAM.
FIG. ID schematically shows a data struc.are of th'.- DVD 100.
In FIG. ID, the record information area KlA comprises a power
calibration area PCA and a recording management area RMA. The
information area IA comprises the lead in area L1A, the data recordable
area DRA and the lead out area LOA.
In the data recordable area DRA, (i) various content data (which
is referred to as "main data" hereinafter) such as audio data, video data
and the like, and di) file management information to manage each main
data as a file are recorded,
The power calibration area PCA is prepared in order to pdjust
the light amount of the optical pickup etc., to thereby perform 'he data
writing operation in an appropriate operation status, by performi>v^ (he
trial data writing operation etc., when performing the daca vvriling
operation in the information recording' and reproducing apparatus.
In the recording management, area RMA, the test result data as
for the power calibration area PCA is recorded.
In the lead in area L1A, the record management data indicative
of the physical information of the disc is recorded.
The lead out area LOA is formed at an end position of the main
data recorded in the data recordable area DRA. In the lead out area
LOA. the data of (00) h is recorded.. The s»t>vt portion of tuning the
load out area LOA is changed depending upon the data amount t. f the
main data. ^ (J*-~T
The arial addresses of those areas PCA, RIA, LIA, DRA and
LOA and the record addresses of the data are set in accordance with die
ECC block address recorded in. the land pre-pit LPP.
FIG. 2 shows the details of the lead in area LIA and the lead out
area LOA.
In FIG, 2. an initial zone is formed at a start position of the lead
in area LIA. The data of (00)h indicative of a blank is set to thi; initial
zone. Following this initial zone, a reference code zone is formed, The
channel bit pattern (3T - OT - 7T) is recorded in this reference code /one.
Code words are repeatedly recorded which are in the conversion table set
in advance as the channel bit pattern. On the basLs of thi.-? channel bit
pattern, the equalizer for the HF signal is adjusted. Following this
reference code zone, a buffer zone of (00)h is formed.
In a control data zone, a DVD format type of the pertinent DVD
(e.g., the DVD-ROM., the DVD-RAM, the DVD-RVV or the like), a part
version, a disc size, a minimum reading out rate, a disc struct ure (e.g.,
one layer ROM disc, one layer RAM disc, two layers ROM/RAM disc or
the like), a recording density, a data area allocation, a burst cutting area
presence or absence, a start seel or of the border zone and -.o for'h are
recorded.
One portion of this control data zone is also assigned as a zone,
where the information important, only for the DVB-ROM is recorded.
Kollowing to this control data zone, a buffer zone of (00)h is formed.
FIG. 3A shows the ba?ic principle of the optical disc recording
method of the present invention. h\ FIG. 3A, the groove track, the hind
track and the land pro-pit of the DVD-RW is schematically illustrated
along a time axis n\ an upper portion of the figure while a timing chart of
the record signal as well as the emboss pit is illustrated :¦)¦: an lower
portion of the figure in correspondence with the upper por.,ion of the
figure.
As shown in FIG. IJA, in case of the DVD-RW. the land pro-pit
method is employed as the track format, The record data is recorded by
irradiating the laser beam onto the groove track. The ECC block
address is recorded in advance by forming the land pro-pit on the land
track.
In FIG. SA, the land pro-pit is indicated by each black
rectangular portion on the land track, while the groove track i-: indicated
by each hatched area, The record signal and the emboss pit with regard
to a small zone A on the groove: track are .ragm"v.:d and .¦iiasr.'au-'d as
the timing' chart at the lower portion of FIG. 3A.
As shown in FTG. :JB, in the DVD 100 (e.g.. the DVD-HW) of the
present embodiment, the emboss pits are formed as intermittent groove
tracks separated by portions of the transparent substraie at an
approximately same level a.-; the land track I;, in the control data /one.
Namely, in the control data zone of the DVD 100, the emboss nil. is
A^tuu convex on the groove track with inspect to the light beam \A}>. Thus, the
reflection coefficient of the groove track G is decreased at the emboss pit.
In FIG. 3B. the proper record mark (which is originally and properly
recorded) is recorded i.n..synchronization wit a the cnooss ph .so thai' the
defection of this proper record mark is not practically influenced by the
emboss pit. In contrast, the detection of the falsified record mark
(which is falsified and is not in synchronization with the emboss pit) is
certainly influenced by the emboss pit, as described later in detail with
referring to FIG. 4 to FIG. 7. Incidentally in FIG. 3B, the wobble of the
groove track G is omitted for the sake of simplicity, and a light spot SP
whose diameter is larger than the width of the groove track G is formed
of the light beam LB.
In the present embodiment, since the data oattem for the data
important only for the DVD-ROM, which is not desiied to be falsified, is
determined in advance, the emboss pit is formed (buriid) in
synchronization with this important data. Therefore, although the
reflection coefficient is decreased due to the existence of the emboss pit-
when the laser beam is irradiated in case of the DVD-EW, the important
data which is recorded in synchronization with the emboss pit is not
influenced when it is read. out. The important data can be written in
such a manner that it. can be normally read oul, since it is in
synchronization with the emboss pit, In contrast, if it is attempted to
(falsify the important data, since the falsified pattern is not ui
synchronization with the emboss pit any more, Uie data cannot be
normally read out. Namely, the important data cannot, bo fnl.sified in
riiich a manner that it can be normally read out since it is not in
synchronization with the emboss pit.
Further, by forming the emboss pit at a central portion of Ihe
record mark or record space whose length iilons the record track is to be
relatively long, even if the start or end position of writing the data by the
laser beam is slightly shifted, a harmful influence is hardly introduced.
In the present embodiments, the emboss pit is formed at the central
portion of the record mark and/or the record space where che record
pulse width is eoual to or wider than about 8T (wherein T denotes a
basic clock cycle). As shown in the lower portion of FIG. 3A, the emboss
pit is formed with respect to each of the record signals having the lengths
of'8T, ISTand MT.
Further, if the emboss: pit does not have a certain h-ii^r.n along
the record track, a probability that the edge of the falsified data crosses
over the emboss pit to thereby give a certain influence is decreased,
resulting in that the falsified data may be normally read out. Namely,
the falsification is successful. Therefore, the emboss pit haying a lengthy
of about 4T is formed with respect to each of the record signals each
having the length equal to or longer than ST .n vhc pivsent
embodiments.
FIG. 4 shows the timing chart shown in FIG. 3A, in mom detail,
of the recording method in a first embodiment of the present invention.
Namely, in FIG, 4, the signal waveforms of the record signal, the
emboss pit, the RF signal and the binary-coded signal in such a condition
that the emboss pit is formed in both of the record mark having the
length of ST along the record track (hereinafter, it is simply referred to
as the r after forming those '.n the
transparent substrate 110. Further, the emboss pit may be embossed
on the groove track if the record signal is recorded on the groove track.
Alternatively, the emboss pit may be embossed on the land track, if the
record signal is recorded on the land track, or may be embossed on the
groove and land tracks if the record signal is recorded on the groove and
land tracks.
In FIG. -1, the record signal and the emboss pit are correlated (in
synchronization) with each other, since the record signal is nut a falsified
one but is a proper one.
The 8T mark is recorded where the emboss pit having tht- length
of 4T along the record track (hereinafter, it is simply referred to as
the "4T emboss pit") is formed. However, since the reflection light, at
the 8T mark is decreased by the ST mark as well as the dT emboss pit,
the RF signal is level-downed redundantly by the 8T mark and the -IT
emboss pit, below the threshold level, whicn is used to convert the RF
signal to the binarycoded signal and is indicated by a dotted line
overlapped on the RF signal. Thus, the binarycoded signal related to
the ST mark is not influenced by the existence of the dT emboss pit here.
In fact, in the example shown in FJG. 4, even if the emboss pit is
not formed in synchronization with the record mark, the RF signal
obtained at the record mark is decreased to the approximately lowest
level due to the existence of the record mark itself. Thus, the RF signal
at the 8T mark below the threshold level is not substantially influenced
by I he existence of the -IT emboss pit in this example. However, the l-tP'
signal at the ST mark may be further level-downed if the RF signal at
'the record mark is not decreased to the lowest level. In th'ls i'.ase, the
principle of the present embodiment is still valid since the further
decrease of the RF signal at the 8T mark due to the 4T emboss pit is only
related to the decrease of the RF signal below the threshold level as long
as the record mark is in synchronization with the emboss pit. Thus, in
this case, the binary-coded signal related to the ST mark is not
influenced by the existence of the 4T emboss pit. either.
The 8T space is recorded where another 4T emboss pit is formed.
However, the decrease of the reflection light amount at the 8T space due
to the existence of the 4T emboss pit is so small that the level-down
amount of the RF signal due to the 4T emboss pit is not enough to
level-down the RF signal below the threshold level. Thus, the
binary-coded signal related to the 8T space is not influenced by the
existence of the 4T emboss pit.
FIG. 5 shows the signal waveforms of the record signal, the
emboss pit, the RF signal and the binary-coded signal in such a condition
that the emboss pit is formed in the same manner as the case of FIG, 4
while the record signal is falsified.
In FIG. 5. the record signal and the emboss pit are not correlated
(in synchronization) with each other any more, since the record .ii^aal is
falsified.
Since one edge of the 8T mark (which represents the falsified
record data) is located at one -IT emboss pit and since (-mother edge of the
8T mark is located at another 4T emboss pit, the reflection light at the
8T mark is decreased at the vicinities of those edges by the existences of
those 4T emboss pits. Thus, the level of the RF signal with respect to
die threshold level is significantly influenced by the existences of those
4T emboss pits, resulting in that the binary-coded signal is significantly
drifted as indicated by drift amounts X and Y in FIG. 5 with respect to
the 8T mark i.e., the falsified record signal.
As clearly understood from FIG, 4 and FIG. 5, according to the
(" i ill i iliin mi. linn it ilt* Miinniii] ninwnl in fulrifinfl in thfi
predetermined zone where the important data is recorded and is not
desired to be falsified, the falsified record data cannot be normally read.
Namely, the falsification of the record data is ended in vain. In this
way, the protection of the record data in a certain zone can be improved
since the falsification can be hardly performed there.
FIG. 6 shows the timing chart shown in FIG. 3A, in more detail
. nf rhn nrnrrlinn msrhnrl in ? larnnii amlinrlimrnr tf ilir rnmwh
If invention?
A Namely, in FIG, G, the signal waveforms of the record signal, the
emboss pit, the RF signal and the binary-coded signal in such a condition
that the 4T emboss pit is formed in the 8T mark but is not formed in the
record space are shown.
In FIG. 6, the record signal and the emboss pit are correlated (in
synchronization) with each other, since the record signal is not a falsified
Although the 8T mark is recorded over the 4T emboss pit, since
the reflection light at, the 8T mark is decreased by the 8T mark as well as
the 4T emboss pit, the RF signal is level-downed redundantly by the ST
mark and the 4T emboss pit, below the threshold level. Thus, the
binsirycorleH signal vJataH in thf* fiT marl; is not. influfmrfid by the
existence of the 4T embus? pit here.
On the other hand, the space is recorded where no emboss pit is
formed. Thus, the binary-coded signal related to the 8T space is not
influenced by the existence of any emboss pit here.
FIG. 7 shows the signal waveforms of the record signal, the
emboss pit, the RF signal and the binary-coded signal in such a condition
that the emboss pit is formed in the same manner as the case of FIG. G
while the record signal is falsified.
In FIG. 7, the record signal and the emboss pit are not correlated
(in synchronization) with each other any more, since the record signal is
falsified.
Since one edge of the 8T mark (which represents the falsified
record data) is located at the 4T emboss pit. the reflection light at ihe 8T
mark is decreased at the vicinity of this edge by the existence of this 4T
emboss pit. Thus., the level of the RF signal with respect to the
threshold level is significantly influenced by the existence of this 4T
emboss pit. Especially, in the second embodiment, since the RF signal is
level-downed by the existence of the 4T emboss pit below the threshold
level the binary-coded signal is quite significantly drifted as indicated by
a drift amount Z in FJG. 7 with respect to the 8T mark i.e., the falsified
record signal.
In the second embodiment, since the emboss pit is not, formed in
the space, it is not necessary to set the depth of the emboss pit so that
the level-downed KF signal due to the emboss pit at the space is above
the threshold level as in the case of the first embodiment. Therefore, in
the second embodiment, the depth of the emboss pit is preferably set
deeper than that in the first embodiment, and is more preferably sot
deep enough to level-down the RF signal below the threshold level By
setting the depth in this manner, the emboss pit in synchronisation with
the 8T mark functions quite effectively to drift the binary-coded signal if
the record signal is falsified.
As clearly understood from FIG. 6 and FIG. 7, according to the
second embodiment, even if the record signal is falsified in the
pi*edetermined zone where the important data is recorded and is not
desired to be falsified, the falsified record data cannot be normally read,
Namely, the falsification of the record data is ended in vain. In this
way, the protection of the record data in a certain zone can be improved
since the falsification can be hardly performed there.
Next, the method of recording the data on the DVD 100 is
explained with reference to FIG. 8.
As shown in FIG. S, at first, a laser cutting process is perlurmed.
Namely, a photo-resist 46 is formed on a glass substrate 45 and is
exposed by a light beam so as to form a pattern of the photo-resist 46
corresponding to the groove track G, the land track L and the land
pre-pit LPP as well as the emboss pit (step SI). Then, the exposed
photo-resist 46 is developed, so that the pattern of the photo-resist 46 is
formed on the glass substrate 45 (step 552). Then, a stamper 47 (i.e., a
so-called stamper disc) is formed by using this pattern of the developed
photo-resist 46 (step S3). Then, the DVD 100 («.g., the DYD-RW),
which has the groove track G, the land track L and the lana pre-pii LPP
as well as the emboss pit, is replicated by using the stamper 47 (step S4).
Then, a pro-write process is performed with respect to the DVD 100.
Namely, the control data etc., are recorded on the control data zone etc.,
by the irradiation of the laser beam LE (step S5).
According to the present embodiment, in the production process
of the DVD 100 at the steps Si to S4, the predetermined data to be
recorded at the pre-write process at the step S5 is known in advance.
Thus, the emboss pit, which is in synchronization with the
predetermined data to be recorded at the pre-write process ai the stop S5,
is formed in the production process at the steps S.1. to S4. Then, in the
pre-write process S5 i.e., the record process before shipment, the
predetermined data is recorded in synchronization with the emboss pit
already formed at the production process at the steps St to S-4,
Therefore, after the pre-write process at the step So e.g., after the
shipment or after the purchase of the DVD 100, even if it is attempted to
falsify the predetermined data in the predetermined zone e.g., the control
zone, the falsified data cannot be normally read out since the falsified
data is not in synchronization with the emboss pit and is significantly
influenced by the emboss pit (refer to FIG. 5 and FIG. 7),
As described above, according to the present embodiments, the
emboss pit is formed (buried) so that the important data recorded in the
control data zone cannot be illegally changed i.e., the important data
recorded in this zone can be normally read out but the illegal rewriting
or falsifying operation cannot be performed in this zone.
In the above described embodiments, the length of the data
pattern i.e., the length of the record mark and/or the record space where
the emboss pit is formed is not limited to 8T. Also, the length of the
emboss pit is not limited to -IT. For example, it is possible to form the
emboss pit having the length of 2T along the record track with respect to
the record mark and/or the record space each having the lom;lh of 4T
along the record track. In any event, the length of the emboss pit along
the record track is shorter than that of the data pattern while the eaiboss
pit is correlated with the data pattern.
Further, it is also possible that the length of the emboss pit
along the record track (e.g., IT to 12T) may be changed depending upon
the length of the record mark and/or the record space along the record
track (e.g., 3T to 14T). By this, since the edge margin between the
emboss pit and the data pattern can be made constant for all the emboss
pits, it is possible to perform the even more reliable data protection.
Furthermore, although such a case has been explained that the
present invention is applied to the DVD-RW, it is also possible to apply
the present invention to the DVD-R or the like, on which the data can be
written only once.
The invention may be embodied in other specific forms without
departing from the spirit or essential characteristics thereof. The
present embodiments are therefore to be considered in all respects as
illustrative and not restrictive, the scope of the invention being indicated
by the appended claims rather than by the foregoing description and all
changes which come within (he meaning and range of equivalency of the
claims are therefore intended to be embraced therein.
The enliro disclosure of Japanese; Patent Application
No.2000-007153 Hied on January 14, 2000 including the specification,
claims,, drawings and summary is incorporated herein by reference in its
entirety.
We claim:
1. A recordable optical disc (100) comprising:
a disc substrate (110);
a record track (102) formed on said disc substrate spirally or coaxially around a
center of said disc substrate (110); and
an emboss pit formed in a predetermined zone on said disc substrate (110) in
correlation with predetermined data, which is recorded on said record track in the
predetermined zone, said recordable optical disc (100) characterized in that said emboss
pit is formed such that said emboss pit does not exist at a boundary between a record
mark and a record space of the predetermined data, but within a record mark or a record
space of the predetermined data.
2. A recordable optical disc as claimed in Claim 1, wherein said emboss pit is
formed at a position where a length of a record mark of the predetermined data along the
record track is equal to or longer than a predetermined length.
3. A recordable optical disc as claimed in Claim 2, wherein a length of said emboss
pit is constant regardless of the length of the record mark.
4. A recordable optical disc as claimed in Claim 2, wherein a length of said emboss
pit is variable depending upon the length of the record mark.
5. A recordable optical disc as claimed in Claim 1, wherein said emboss pit is
formed at a position where a length of a record space of the predetermined data along the
record track is equal to or longer than a predetermined length.
6. A recordable optical disc as claimed in Claim 5, wherein a length of said emboss
pit is constant regardless of the length of the record space.
7. A recordable optical disc as claimed in Claim 5, wherein a length of said emboss
pit is variable depending upon the length of the record space.
8. A recordable optical disc as claimed in Claim 1, wherein a plurality of emboss
pits each having a structure same as the emboss pit are formed in the predetermined zone.
9. A recordable optical disc as claimed in Claim 8, wherein a first emboss pit of the
emboss pits is formed at a position where a length of a record mark of the predetermined
data along the record track is equal to or longer than a predetermined length and a second
emboss pit of the emboss pits is formed at a position where a length of a record space of
the predetermined data along the record track is equal to or longer than the predetermined
length.
10. A recordable optical disc as claimed in Claim 9, wherein a length of said first
emboss pit along the record track is variable depending upon the length of the record
mark and a length of said second emboss pit along the record track is variable depending
upon the length of the record space.
11. A recordable optical disc as claimed in Claim 8, wherein a length of each of the
emboss pits along the record track is constant.
12. A recordable optical disc as claimed in Claim 1, wherein the predetermined zone
is in a control data zone, and the predetermined data is control data to control a recording
and /or reproducing operation of data recorded on said record track in a data record zone,
which is different from the predetermined zone and where said emboss pit is not formed.
13. A recordable optical disc as claimed in Claim 12, wherein said control data zone
is within a lead in area.
14. A recordable optical disc as claimed in Claim 1, wherein data other than the
predetermined data is recorded on said record track in a data record zone, which is
different from the predetermined zone and where said emboss pit is not formed.
15. A recordable optical disc as claimed in Claim 1, comprising a record layer, which
is formed on said disc substrate and by which data including the predetermined data is
recorded on said record track.
16. A recordable optical disc as claimed in Claim 15, wherein said record layer
comprises a material capable of a recording operation of write many times type.
17. A recordable optical disc as claimed in Claim 15, wherein and record layer
comprises a material capable of a recording operation of write once type.
18. A recordable optical disc as claimed in Claim 15, wherein said record layer
comprises a material capable of a recording operation of write limited times type.
19. A recordable optical disc as claimed in Claim 1, further comprising a reflective
layer formed on said disc substrate for reflecting a light beam for a recording and/or
reproducing operation of data recorded on the record track.
20. A method of recording data on a recordable optical disc (100) comprising: a disc
substrate (110); and a record track (102) formed on said disc substrate (110) spirally or
coaxially around a center of said disc substrate (110); and an emboss pit formed in a
predetermined zone on said disc substrate (110) in correlation with predetermined data,
which is recorded on said record track (102) in the predetermined zone, characterized in
that
said method comprises the steps of:
forming the emboss pit on the disc substrate (110) such that said embossed pit
does not exist at a boundary between a record mark and a record space of the
predetermined data, but within a record mark or a space of the predetermined data; and
recording the predetermined data in the predetermined zone.
21. A method as claimed in Claim 20, further comprising a process of recording data
other than the predetermined data in a data record zone, which is different from the
predetermined zone where said emboss pit is not formed

A recordable optical disc (100) is provided with a disc substrate (110); a record track
(102) formed on the disc substrate spirally or coaxially around a center of the disc substrate;
and an emboss pit formed in a predetermined zone on the disc substrate in correlation with
predetermined data, which is recorded on the record track in the predetermined zone.