1. An optical disc (1) comprising: a recordable area (RIA, IA) comprising an information track (102, G) in which an information signal is to be recorded; a first emboss area in which first emboss pits array are formed; and a second emboss area in which second emboss pits array are formed, wherein the first emboss pits array have physically different structure from the second emboss pits array.

2. An optical disc (1) as claimed in claim 1, wherein the second emboss area is disposed immediately after the first emboss area.

3. An optical disc (1) as claimed in claim 1 or 2, wherein the first emboss pits array have a different pit depth from the second emboss pits array.

4. An optical disc (1) as claimed in claim 3, wherein the first emboss pits array have a first depth, and the second emboss pits array have a second depth which is shallower than the first depth.

5. An optical disc (1) as claimed in any one of claims 1 to 4, wherein the first emboss pits array and second emboss pits array are wobbled respectively.

6. An optical disc (1) as claimed in any one of claims 1 to S, wherein control data is recorded in the first emboss area as the first emboss pits array.

7. An optical disc (1) as claimed in any one of claims 1 to 6, wherein dummy data is recorded in the second emboss area as the second emboss pits array.

8. An optical disc (1) as claimed in any one of claims 1 to 7, wherein each of the first emboss pits array and second emboss pits array has a size which is an integral multiple of a size of an error correction unit.

9. An optical disc (1) as claimed in any one of claims 1 to 8, wherein the first emboss area is larger than the second emboss area.

10. An optical disc (1) as claimed in claim 9, wherein the first emboss area has Ml pieces of ECC blocks and the second emboss area has M2 pieces of ECC blocks, wherein the M2 is smaller number than the Ml.

11. An optical disc (1) as claimed in claim 9 or 10, wherein the first emboss area is a readable emboss area and the second emboss area is an unreadable emboss area.

12. An optical disc (1) as claimed in any one of claims 9 to 11, wherein the disc comprises a lead-in area comprising at least an initial zone and a control data zone and comprising a reference code zone, a first buffer zone and a second buffer zone.

13. An optical disc (1) as claimed in claim (10), wherein the number of Ml is equal to 176 and the number of M2 is equal to 16.

14. A method of producing an optical disc (1) comprising: a recordable area (RIA, LA) forming process of forming a recordable area (RIA, LA) comprising an information track (102, G) in which an information signal is to be recorded; a first emboss area forming process of forming a first emboss area in which first emboss pits array are formed; and a second emboss area forming process of forming a second emboss area in which second emboss pits array are formed, which have physically different structure from the first emboss pits array.

15. A method of producing an optical disc (1) as claimed in claim 14, wherein the second emboss area forming process disposes the second emboss area immediately after the first emboss area.

16. A method of producing an optical disc (1) as claimed in claim 14 or 15, wherein the first emboss pits array have a different pit depth from the second emboss pits array.

17. A method of producing an optical disc (1) as claimed in claim 16, wherein the first emboss pits array have a first depth, and the second emboss pits array have a second depth which is shallower than the first depth.

18. A method of producing an optical disc (1) as claimed in any one of claims 14 to 17, wherein the first emboss pits array and second emboss pits array are wobbled respectively.

19. A method of producing an optical disc (1) as claimed in any one of claims 14 to 18, wherein control data is recorded in the first emboss area as the first emboss pits array.

20. A method of producing an optical disc (1) as claimed in any one of claims 14 to 19, wherein dummy data is recorded in the second emboss area as the second emboss pits array.

21. A method of producing an optical disc (1) as claimed in any one of claims 14 to 20, wherein each of the first emboss pits array and second emboss pits array has a size which is an integral multiple of a size of an error correction unit.

22. A method of producing an optical disc (1) as claimed in any one of claims 14 to 21, wherein the first emboss area is larger than the second emboss area.

23. A method as claimed in claim 22, wherein the first emboss area has Ml pieces of ECC blocks and the second emboss area has M2 pieces of ECC blocks, wherein the M2 is smaller number than the Ml.

24. A method as claimed in claim 22 or 23 wherein the first emboss area is a readable emboss area and the second emboss area is an unreadable emboss area.

25. A method as claimed in any one of claims 22 to 24, wherein the disc comprises a lead-in area comprising at least an initial zone and a control data zone and comprising a reference code zone, a first buffer zone and a second buffer zone.

26. A method as claimed in claim 23, wherein the number of Ml is equal to 176 and the number of M2 is equal to 16.

27. An apparatus for producing an optical disc (1) comprising: a recordable area (RIA, LA) forming device for forming a recordable area (RIA, LA) comprising an information track (102, G) in which an information signal is to be recorded; a first emboss area forming device for forming a first emboss area in which first emboss pits array are formed; and a second emboss area forming device for forming a second emboss area in which second emboss pits array are formed, which have physically different structure from the first emboss pits array.

28. An apparatus for producing an optical disc (1) as claimed in claim 27, wherein the second emboss area forming devices disposes the second emboss area immediately after the first emboss area.

29. An apparatus for producing an optical disc (1) as claimed in claim 27 or 28, wherein the first emboss pits array have a different pit depth from the second emboss pits array.

30. An apparatus for producing an optical disc (1) as claimed in claim 29, wherein the first emboss pits array have a first depth, and the second emboss pits array have a second depth which is shallower than the first depth.

31. An apparatus for producing an optical disc (1) as claimed in any one of claims 27 to 30, wherein the first emboss pits array and second emboss pits array are wobbled respectively.

32. An apparatus for producing an optical disc (1) as claimed in any one of claims 27 to 31, wherein control data is recorded in the first emboss area as the first emboss pits array.

33. An apparatus for producing an optical disc (1) as claimed in any one of claims 27 to 32, wherein dummy data is recorded in the second emboss area as the second emboss pits array.

34. An apparatus for producing an optical disc (1) as claimed in any one of claims 27 to 33, wherein each of the first emboss pits array and second emboss array has a size which is an integral multiple of a size of an error correction unit.

35. An apparatus for producing an optical disc (1) as claimed in any one of claims 27 to 34, wherein the first emboss area is larger than the second emboss area.

36. An apparatus as claimed in claim 35, wherein the first emboss area has Ml pieces of ECC blocks and the second emboss area has M2 pieces of ECC blocks, wherein the M2 is smaller number than the Ml.

37. An apparatus as claimed in claim 35 or 36 wherein the first emboss area is a readable emboss area and the second emboss area is an unreadable emboss area.

38. An apparatus as claimed in any one of claims 35 to 37, wherein the disc comprises a lead-in area comprising at least an initial zone and a control data zone and comprising a reference code zone, a first buffer zone and a second buffer zone.

39. An apparatus as claimed in claim 36, wherein the number of Ml is equal to 176 and the number of M2 is equal to 16. This invention comprises an optical disc (1) provided with a recordable area (R1A, 1A) having an information track (102, G) in which an information signal is to be recorded, a first emboss area in which first emboss pits array are formed and a second emboss area in which second emboss pits array are formed, wherein the first emboss pits array have physically different structure from the second emboss pits array. The invention further provides a method and apparatus for producing an optical disc (1).

OPTICAL DISC, AND METHOD OF AND APPARATUS FOR
RECORDING SIGNAL ONTO THE SAME
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical disc and a method
of and an apparatus for recording a signal onto the optical disc, which
is especially suitable for a DVD-RW (DVD Re-recordable).
2. Description of the Related Art
There are various types of optical discs, because of the
diversification of formats of the CDs (Compact Discs) 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 be written many
times. According to the formats of the DVDs, there are a read only type
DVD-ROM (DVD Read 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 times and can be written only once, a re-recordable type
DVD-RW (DVD Re-recordable) on which data can be read many times and
can be written for limited times, and a rewritable type DVD-RAM (DVD
Rewritable) on which data can be read many times and can be written many
times.
FIG. 13 shows an example of a data structure and allocations of

addresses in a lead in area in the format of the DVD-RW.
In FIG. 13, an initial zone having 3078 ECC blocks is allocated from
an ECC block address of "0022FA"h , which is a start position of the lead in
area belonging to a readable emboss data zone, where data cannot be
rewritten. In this initial zone, all "00"h data are set which imply a blank.
A reference code zone having 2 ECC blocks is allocated from the ECC block
address "002F00"h following this emboss data zone. In this reference code
zone, an emboss reference code is recorded. More concretely, a code within a
conversion table set in advance as the emboss reference code is repeated.
The apparatus is set such that this predetermined code word can be correctly
read out, in other words, the code word can be read out within a
predetermined error rate range. Following to this reference code zone, a
first buffer zone having 30 ECC blocks is allocated in which all data "00"h are
set which imply a blank again from the ECC block address "002F02"h.
A control data zone having 192 ECC blocks is allocated which starts
from the next ECC block address "002F20"h. In this control data zone,
control data, which is essentially composed of 16 sectors (i.e., 1 ECC block),
and has (i) a physical format information explained below (of 1 sector), (ii) a
disc production information area (of 1 sector) and (iii) an empty information
area (of 14 sectors), is recorded repeatedly by 192 times. Here, as the
physical format information, there are recorded the type of the applied DVD
standard (e.g., the DVD-ROM, the DVD-RAM, the DVD-RW or the like), the
part version, the disc size, the minimum read out rate, the disc structure (e.g.,
one layer ROM disc, one layer RAM disc, two layers ROM/RAM disc or the
like), the record density, the data area allocation, the condition of linear
velocity to specify the exposure light amount at the time of recording in the
burst cutting area, the reading out power, the peak power, the bias power,
various information with regard to the production of the medium and so on.
In the empty information areaT important data such as copy right protection
information or the like is recorded at an arbitrary position therein.
According to the DVD-RW standard, in order to prevent an illegal
re-writing operation, emboss pits are randomly formed (buried) in the control
data zone consisting of 192 ECC blocks, so that the control data cannot be
read out or recorded in this control data area as the unreadable emboss area.
Incidentally, according to the DVD-RW standard, the control data is recorded
at a different position.
As described above, the control data zone is recorded as a zone where
the data cannot be read out or recorded, according to the DVD-RW standard.
However, a development of such an optical disc (i.e., the DVD-RW) is
demanded that the data cannot be written but the data can be read in the
control data zone, which is at the same position as in the case of the DVD
video (or the DVD-ROM), so as to enable the reproduction of the DVD-RW by
a DVD video player.
However, if the emboss pit is recorded as the data actually readable
in the same manner as the CD, the data in the control data zone cannot be
read due to the existence of a land pre-pit (indicating a guide signal) on a
land portion according to the DVD-RW standard. The land pre-pit signal is
necessary to write data to a next area on the DVD-RW. Thus, the land
pre-pit cannot be omitted, and thereby data cannot be written by the
readable emboss pit in the control data zone as a result.
In this manner, if it is attempted to record data in the control data
zone by the emboss pit, since the land pre-pit signal with an adequate signal

quality cannot be obtained, it is difficult or impossible to record data into an
area immediately after the control data zone, which is a problem.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an
optical disc, and a method of and an apparatus for recording a signal
onto the optical disc, which enables to record data into the area
immediately after the control data zone and which preserves the
compatibility with a conventional optical disc.
The above object of the present invention can be achieved by
an optical disc provided with: a disc substrate; an information track
formed on the disc substrate spirally or coaxially around a center of
the disc substrate, on which an information signal including a physical
sector number is to be recorded,' and a guide track adjacent to the
information track and formed on the disc substrate spirally or
coaxially around the center, on which a guide signal including address
information is to be recorded, wherein a readable emboss area, in
which the information signal is recorded by an emboss pit, and an
unreadable emboss area, in which an unreadable emboss pit to disable
writing and reading the information signal, are formed on the
information track, and the guide signal is not recorded on the guide
track corresponding to the readable emboss area and the guide signal
is recorded on the guide track corresponding to the unreadable emboss
area.
The above object of the present invention can be also achieved
by another optical disc provided with: a disc substrate; an information
track formed on the disc substrate spirally or coaxially around a center
of the disc substrate, on which an information signal including a
physical sector number is to be recorded; and a guide track adjacent to
the information track and formed on the disc substrate spirally or
coaxially around the center, on which a guide signal including address
information is to be recorded, wherein a readable emboss area, in
which the information signal is recorded by an emboss pit, and an
unreadable emboss area, in which an unreadable emboss pit to disable
writing and reading the information signal, are formed on the
information track, and the guide signal is recorded on the guide track
except the guide track corresponding to the readable emboss area.
In one aspect of the optical disc of the present invention, the
unreadable emboss area is disposed immediately after the readable
emboss area.
In another aspect of the optical disc of the present invention,
the address information of the guide signal corresponding to the
unreadable emboss area is set on the basis of the address information
of the guide signal corresponding to a lead of a data record area of the
optical disc.
According to the optical disc of the present invention, it
becomes possible to record data into an area immediately after the
unreadable emboss area, and an optical disc on which the data cannot
be written into the control data zone and the data can be read out in
the control data zone can be realized. Further, by adjusting the
inconformity of the addresses due to the existence of the unreadable
emboss, it is possible to maintain the address compatibility with the
disc in the conventional version.
The above object of the present invention can be also achieved
by a method of recording an information signal and a guide signal onto
the above described optical disc of the present invention. The
recording method includes^ a process of forming a readable emboss
area, in which the information signal is recorded by an emboss pit, and
an unreadable emboss area, in which an unreadable emboss pit to
disable writing and reading the information signal, on the information
track, and a process of recording the guide signal onto the guide track
corresponding to the unreadable emboss area, without recording the
guide signal on the guide track corresponding to the readable emboss
area.
The above object of the present invention can be also achieved
by another method of recording an information signal and a guide
signal onto an optical disc comprising (i) a disc substrate, (ii) an
information track formed on the disc substrate spirally or coaxially
around a center of the disc substrate, on which the information signal
including a physical sector number is to be recorded and (iii) a guide
track adjacent to the information track and formed on the disc
substrate spirally or coaxially around the center, on which the guide
signal including address information is to be recorded. The recording
method includes: a process of forming a readable emboss area, in
which the information signal is recorded by an emboss pit, and an
unreadable emboss area, in which an unreadable emboss pit to disable
writing and reading the information signal, "on the information track,
and a process of recording the guide signal onto the guide track except
the guide track corresponding to the readable emboss area.
In one aspect of the recording method of the present invention,
the unreadable emboss area is disposed immediately after the readable
emboss area.
In another aspect of the recording method of the present
invention, the address information of the guide signal corresponding to
the unreadable emboss area is set on the basis of the address
information of the guide signal corresponding to a lead of a data record
area of the optical disc.
According to the recording method of the present invention,
since the unreadable emboss zone is added between the control data
zone as the readable emboss zone and the buffer zone which follows
the control data zone, or since the unreadable zone is allocated in one
portion of the buffer zone which follows the control data zone or one
portion of the control data zone, it becomes possible to record the data
into the area immediately after the unreadable zone. Further, since
the address of the guide track corresponding to the unreadable area is
determined so as to make the physical sector number with the
conventional DVD-RW version, it becomes possible to maintain the
address compatibility with the disc in the conventional version. As
long as there is no interruption or disturbance to the operation of
recording the data into the data area following the unreadable emboss
zone, it is not required to perform a complicated address operation to
maintain the compatibility with the DVD-RW of the conventional
version.
The above object of the present invention can be also achieved
by an apparatus for recording an information signal and a guide signal
onto the above described optical disc of the present invention. The
recording apparatus includes^ an emboss area forming device for
forming a readable emboss area, in which the information signal is
recorded by an emboss pit, and an unreadable emboss area, in which
an unreadable emboss pit to disable writing and reading the
information signal, on the information track, and a recording device
for recording the guide signal onto the guide track corresponding to
the unreadable emboss area, without recording the guide signal on the
guide track corresponding to the readable emboss area.
The above object of the present invention can be also achieved
by another apparatus for recording an information signal and a guide
signal onto an optical disc comprising (i) a disc substrate, (ii) an
information track formed on the disc substrate spirally or coaxially
around a center of the disc substrate, on which the information signal
including a physical sector number is to be recorded and (iii) a guide
track adjacent to the information track and formed on the disc
substrate spirally or coaxially around the center, on which the guide
signal including address information is to be recorded. The recording
apparatus is provided with: an emboss area forming device for forming
a readable emboss area, in which the information signal is recorded by
an emboss pit, and an unreadable emboss area, in which an
unreadable emboss pit to disable writing and reading the information
signal, on the information track, and a recording device for recording
the guide signal onto the guide track except the guide track
corresponding to the readable emboss area.

In one aspect of the recording apparatus of the present
invention, the recording device allocates a physical sector address of
the unreadable emboss area immediately after the readable emboss
area.
In another aspect of the recording apparatus of the present
invention, the recording device sets the address information of the
guide signal corresponding to the unreadable emboss area, to a value
based on the address information of the guide signal corresponding to
a lead of a data record area of the optical disc.
According to the recording apparatus of the present invention,
it becomes possible to record the data into the area immediately after
the unreadable emboss area. The data cannot be written into the
control data zone but the data can be read out from the control data
zone. By adjusting the inconformity of the addresses due to the
allocation of the unreadable emboss, it is possible to maintain the
address compatibility with the disc in the conventional version.
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.
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-RW used in the embodiments;
FIG. 2A is a diagram showing a positional relationship
between a groove and a land of the DVD-RW shown in FIG. ID;
FIG. 2B is a magnified partial perspective view of the
DVD-RW showing emboss pits,'
FIG. 3 is a diagram showing a detailed structure of a lead in
area shown in FIG. ID in one embodiment;
FIG. 4A is one diagram showing a data structure in a signal
record format of the DVD-RW in the embodiments;
FIG. 4B is another diagram showing a data structure in the
signal record format of the DVD-RW in the embodiments;
FIG. 5 is another diagram showing a data structure in the
signal record format of the DVD-RW in the embodiments.'
FIG. 6 is a block diagram showing an internal structure of a
disc production apparatus, to which the signal recording method of the
present invention is applied, in the embodiments;
FIG. 7 is a flowchart showing an operation procedure of a disc
production apparatus shown in FIG. 6;
FIG. 8 is a process chart showing a method of producing the
disc of the embodiment;
FIG. 9 is a diagram showing a detailed structure of a lead in
area in another embodiment;

FIG. 10 is a flowchart showing an operation procedure of a disc
production apparatus to producing a disc corresponding to FIG. 9.'
FIG. 11 is a diagram showing a detailed structure of a lead in
area in another embodiment;
FIG. 12 is a flowchart showing an operation procedure of a disc
production apparatus to producing a disc corresponding to FIG. 11;
and
FIG. 13 is a diagram showing a detailed structure of a lead in
area as well as an address allocation in a DVD-RW format in a related
art.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the accompanying drawings, embodiments of the
present invention will be now explained.
In FIG. 1A, a DVD-RW 1 is provided with a transparent
substrate 110 having a center hole 103 and record tracks 102 spiral or
coaxial around the center hole 103. From the inner circumferential
side toward the outer circumferential side on the DVD-RW 1, there are
formed- a clamping area CA which is clamped by a clamper when the
DVD-RW 1 is set to an information recording and/or reproducing
apparatus.' a record information area RIA; and an information area IA.
In the information area IA, there are formed a lead in area LIA, 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 RIA as well as the information area IA.
As shown in FIG. IB, the record tracks 102 consist of (i) a land
track L comprising a land, which is convex on the transparent
substrate 110 and is concave with respect to a laser beam LB 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 land pre-pit LPP is formed. The land pre-pit LPP is used
to define the physical address on the record track 102. The groove
track G are wobbled at a predetermined frequency.
On the basis of the information indicated by the land pre-pit
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 be recorded on the land track L in
place of or in addition to the groove track G.
As shown in FIG. 1C, on the transparent substrate 110, a
record layer 111, a light reflective layer 112 and a protection layer 113
are laminated, for example. 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. Alternatively, the record
layer 111 may comprise a dye e.g., a material whose optical property is
changed when a writing laser beam which is stronger than a reading
laser beam is irradiated, in case of the DVD-R.
FIG. ID schematically shows a data structure of the DVD-RW
1.
In FIG. ID, the record information area RIA comprises a power
calibration area PCA and a recording management area RMA. The
information area IA comprises the lead in area LIA, the data
recordable area DRA and the lead out area LOA.
In the data recordable area DRA, (i) various content data such
as audio data, video data and the like, and (ii) file management
information to manage each main data as a file are recorded.
In the recording management area RMA, the record
management data indicating the record conditions of the content data
recorded in the data recordable area DRA as well as the lead in area
LIA and the lead out area LOA is recorded.
The power calibration area PCA is prepared in order to adjust
the light amount of the optical pickup etc., to thereby perform the data
writing operation in an appropriate operation status, by performing
the trial data writing operation etc., when performing the data writing
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 also recorded.
In the lead in area LIA, 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 start position of recording the
lead out area LOA is changed depending upon the data amount of the
main data.
The areal addresses of those areas PCA, RIA, LIA, DRA and
LOA and the record addresses of the data are set in accordance with
the ECC block address recorded in the land pre-pit LPP.
FIG. 2A shows a diagram showing a positional relationship
between the groove and the land in the DVD-RW.
In FIG. 2A, a groove track 2 and a land track 3 are spirally or
coaxially disposed adjacent to each other. A physical sector number
of the groove track 2 is generated with referring to the address
information of a land pre-pit 4 (indicating a guide signal), which is
written on the land track 3 (as a guide track), and the information
signal is recorded onto the groove track 2, in the operation.
Here, a physical structure of an emboss pit is explained with
reference to FIG. 2B.
As shown in FIG. 2B, in the DVD-RW, the unreadable emboss
pits are formed as intermittent groove tracks separated by portions of
the transparent substrate at an approximately same level as the land
track 3. Namely, the emboss pit is convex on the groove track 2 with
respect to the light beam LB. Thus, the reflection coefficient of the
groove track 2 is decreased at the emboss pit. Incidentally in FIG. 2B,
the wobble of the groove track 2 is omitted for the sake of simplicity,
and a light spot SP whose diameter is larger than the width of the
groove track 2 is formed of the light beam LB.
FIG. 3 shows the details of the lead in area LIA.
In FIG. 3, an initial zone is formed at a start position of the lead in
area LIA, which belongs to an unreadable emboss data zone where the
re-writing operation is not possible. The data of "00"h indicative of a blank
is set to this initial zone. Following this initial zone, a reference code zone is
formed. In this reference code zone, an emboss reference code is recorded.
A code word is repeatedly recorded which is in the conversion table set in
advance as the emboss reference code. The apparatus is set such that this
predetermined code word can be correctly read out, in other words, the code
word can be read out within a predetermined error rate range. Following to
this reference code zone, a first buffer zone is allocated in which all data
"00"h are set which imply a blank again.
In a control data zone in the emboss data zone, there are recorded
the type of the applied DVD standard (e.g., the DVD-ROM, the DVD-RAM,
the DVD-RW or the like), the part version, the disc size, the minimum read
out rate, the disc structure (e.g., one layer ROM disc, one layer RAM disc, two
layers ROM/RAM disc or the like), the record density, the data area
allocation, the condition of linear velocity to specify the exposure light
amount at the time of recording in the burst cutting area, the reading out
power, the peak power, the bias power, various information with regard to
the production of the medium and so on.
In the present embodiment, an unreadable emboss area is formed
between this control data zone and a second buffer zone which is blank. In
the control data zone, the control data is recorded by a deep emboss pit
(whose depth is 70 to 80 nm)-which starts from the sector number of
"02F200"h, and the land pre-pit 4 which may become the obstacle when
reading is not recorded. Then, an unreadable emboss area is formed. In
this unreadable emboss area, the land pre-pit 4 is inserted and the shallow
emboss pit (whose depth is about 20 nm) is recorded on the basis of dummy
data so that the information signal cannot be recorded or reproduced.
As the land-pre pit 4 is interrupted, the rising up upon recording the
data onto the second buffer zone following it is degraded. Thus, the
unreadable emboss area of 64 ECC blocks is formed following to this control
data zone. In this unreadable emboss area, the land pre-pit 4 is inserted,
and thereby a shallow emboss pit based on the dummy data is recorded so
that the information signal cannot be recorded or reproduced. In the second
buffer zone next to it, the blank data "00"h is recorded and the lead in area is
ended.
In this manner, since the unreadable emboss area having the 64
ECC blocks for example is newly added between the control data zone having
the 192 ECC blocks and the buffer zone, mismatching or unconformity of the
address is generated with respect to the conventional DVD-RW version.
Therefore, the address of the guide track corresponding to the unreadable
emboss area is determined so as to match the physical sector number with
the conventional DVD-RW version. Namely, since the physical sector
number is made continuous before and after the unreadable emboss area,
and since the length of the ECC block address is different in length between
the readable emboss area and the unreadable emboss area, the ECC block
address is not continuous before and after the unreadable emboss area.
Therefore, it is necessary to absorb the difference of the address of the 192
ECC blocks and the address of the 64 ECC blocks by the buffer zone.
For this reason, to the address information of the guide signal
corresponding to the unreadable emboss area, the value based on the address
information of the guide signal corresponding to the lead of the data area (e.g.,
the ECC block address "003000"h) is set. Namely, to the lead address of the
unreadable emboss area, the value (i.e., "002FA0"h) which is obtained by
subtracting (i) the 64 ECC blocks (i.e., "000040"h) as the length of the
unreadable emboss area and (ii) the 32 ECC blocks ("000020"h) as the length
of the buffer zone from the lead address "003000"h as the lead address of the
data area is set.
FIG. 4A, FIG. B and FIG. 5 show the signal record format of the
DVD-RW used in the present embodiment. Here, the physical format upon
recording the record information onto the DVD-RW and the error correction
process for the record information are explained with reference to those
figures.
At first, the error correction in the DVD-RW and the ECC block as
an error correction unit in the error correction process are explained with
reference to FIG. 4A and FIG. 4B.
The record information recorded on the DVD-RW is constructed to
have a physical structure including a plurality of data sectors 20 shown in
FIG. 4A. Then, one data sector 20 includes, in the order from the lead
thereof, (i) ID information 21 indicating a start position of the data sector 20,
(ii) an ID information error correction code IEC (ID data Error Correction
code) 22 to correct the error in the ID information 21, (iii) reserved data 23,
(iv) data 24 which is the main data to be recorded and (v) an error detection
code EDC (Error Detection Code) 25 to detect an error in the data 24. The
record information to be recorded is constructed as a plurality of data sectors
20 are sequentially continued. The ID information 21 is constructed by 4
bytes in total of the sector information having 1 byte and the sector number
having 3 bytes. As the sector information, there are a layer to which the
sector number belongs, the area and the like.
Next, the process of constructing the ECC block by using the data
sector 20 is explained with reference to FIG. 4B. When constructing the
ECC block by using the data sector 20, at first, one data sector 20 is divided
for each 172 bytes, and the respective divided data (which are referred to as
"data blocks 33" hereinbelow) are arranged in a vertical direction as shown in
FIG. 4B at its left portion. At this time, 12 lines of data blocks 33 are
arranged in the vertical direction. Then, the ECC parity in code (PI (Parity
In) code) 31 having 10 bytes is added to the end of the respective one of the
data blocks 33 arranged in the vertical direction, so as to construct one
correction block 34 as shown in FIG. 4B at its right portion. At this stage,
the correction blocks 34 to each of which the ECC parity in code 31 is added
are arranged in 12 lines. After that, this process is repeated for 16 data
sectors 20. By those processes, the correction blocks 34 having 192 lines are
obtained.
Next, in such a condition that the correction blocks 34 in the 192
lines are arranged in the vertical direction, the correction blocks 34 in the 192
lines are' divided in the vertical direction from the beginning thereof for each
one byte, and 16 ECC parity out codes (PO (Parity Out) codes) 32 are added
to the respective one of the divided data. Incidentally, the ECC parity out
code 32 is added to the portion of the ECC parity in code 31 among the error
correction block 34.
By the above mentioned processes, one ECC block 30 including 16
data sectors 20 are formed as shown in FIG. 4B at its right portion. At this
time, the total amount of the information included in one ECC block 30 is
(172 + 19) bytes X (192 + 16) lines = 37856 bytes. Among these, the actual
data 24 is 2048 bytes X 16 lines = 32768 bytes. Further, in the ECC block
30 shown in FIG. 4B at its right portion, the one byte data is indicated by "D
#. *". For example, "Dl.O" indicates the one byte data which is disposed at
the 1st line and the 0th column. "D190.170" indicates the one byte data
which is disposed at the 190th line and the 170th column. Therefore, the
ECC parity in code 31 is disposed at the 172nd column to the 181st column.
The ECC parity out code 32 is disposed at the 192nd line to the 207th line.
Further, one correction block 34 is recorded continuously on the
DVD-RW. Here, the reason why the ECC block 30 is constructed to include
both of the ECC parity in code 31 and the ECC parity out code 32 as shown in
FIG. 4B at its right portion is that the correction of the data arranged in the
horizontal direction in FIG. 4B at its right portion is performed by use of the
ECC parity in code 31, and the correction of the data arranged in the vertical
direction in FIG. 4B at its right portion is performed by using the ECC parity
out code 32.
Namely, in the ECC block 30 shown in FIG. 4B at its right portion, it
is possible to perform the error correction redundantly in the horizontal
direction and the vertical direction, so that the error correction more powerful
than the conventional error correction process used for the conventional CD
or the like can be performed.
More concretely as for this point, for example, even if all of one
correction block 34 (which includes the data of 182 bytes in total including
the ECC parity in codes 31 in one line amount and is recorded continuously
on the DVD-RW as mentioned above) is destroyed by a scratch etc., of the
DVD-RW, it is the data destruction of merely one byte with respect to the
ECC parity out code 32 in one column if it is seen from the vertical direction.
Therefore, even if one correction block 34 is completely destroyed, it is
possible to correctly reproduce the data by performing the error correction as
long as the correction using the ECC parity out code 32 of the respective one
of the columns is performed.
Next, how to record the data sector 20, which is constructed in the
ECC block 30 as shown in FIG. 4B at its right portion, onto the DVD-RW is
explained with reference to FIG. 5. In FIG. 5, the data indicated by "D #. * "
corresponds to the data described within FIG. 4B at its right portion.
When recording the ECC block 30 onto the DVD-R, at first, the ECC
blocks 30 are arranged in one row in the horizontal direction for each
correction block 34 to be thereby interleaved as shown in FIG. 5 at its top
portion, so that the ECC block 30 is divided into the 16 recording sectors 40.
At this time, one recording sector 40 includes the information of 2366 bytes
(i.e., 37856 bytes -H 16). The data sector 20 and the ECC parity in code 31
or the ECC parity out code 32 are mixed in this one recording sector 40. At
the lead of each recording sector 40, the ID information 21 of the data sector
20 (referring to FIG. 4A) is disposed.
Then, each recording sector 40 is divided into the data 41 for each 91
bytes, and a header H is added to each of them. After that, by 8-16
modulating the recording sector 40 in this status, one synchronization frame
42 is formed for each data 41. At this time, one synchronization frame 42 is
constructed by the header H and the data 43. The information amount
within one synchronization frame 42 is 91 bytes X 8 X (16/8) = 1456 bytes.
The information is written onto the DVD-RW in such a condition that the
synchronization frames 42 are continued. At this time, one recording sector
40 includes 26 synchronization frames 42.
By constructing the above explained physical format and thereby
recording the information onto the DVD-RW, if the 8*16 demodulation and
the de-interleave are performed upon reproducing the information from the
DVD-RW (refer to FIG. 5), it is possible to recover the original ECC block 30,
so that it is possible to correctly reproduce the information while performing
the powerful error correction.
FIG. 6 to FIG. 8 are diagrams explaining the operation of the
embodiment, and respectively showing the internal structure of the disc
production apparatus, the flowchart of its operation and the procedures of the
disc production method.
In the present embodiment, a disc production apparatus shown
in FIG. 6 is used in order to produce the optical disc.
As shown in FIG. 8, when producing the DVD-RW, a laser
cutting operation by use of the disc production apparatus is performed
at first (step Si). More concretely, a photo-resist 15 is formed on a
glass substrate 14 and is exposed by a .light beam so as to form a
pattern of the photo-resist 15 corresponding to the groove track G, the
land track L and the land pre-pit LPP as well as the emboss pit.
Then, the exposed photo-resist 15 is developed, so that the pattern of
the photo-resist 15 is formed on the glass substrate 14 (step S2).
Then, a master stamper 47 (i.e., a so-called stamper disc) is formed by
using this pattern of the developed photo-resist 15 (step S3). Then, a
sub-master stamper 48 is formed by applying the electrocasting
process once with respect to the master stamper 47 (step S4).
Alternatively, a stamper may be obtained by applying the
electrocasting process even times with respect to this sub-master
stamper 48. Then, an emboss process may be performed (step S5),
and the DVD-RW ,1 having the groove 2 and the land 3 is finally
produced by an replication process using the sub-master stamper 48
(step S6). By the above mentioned laser cutting process, since the
cutting process of the original disc is performed just once, the pre-pit 4
is not drifted on the land 3, so that the DVD-RW 1 which is quite
accurate can be produced.
FIG. 6 shows a disc production apparatus using the above
mentioned laser cutting operation.
In FIG. 6, the disc production apparatus is provided with: a
laser generating device 10 of large output type for emitting a laser
beam; a light modulator 11 for modulating the laser beam from the
laser generating device 10; an objective lens 13 for collecting the
modulated laser beam so as to form a light spot on the photo-resist 15
on the glass substrate 14; encoders 12A and 12B for encoding land
cutting information; a controller 50 for controlling the encoders 12A
and 12B as well as other constitutional elements; and a modulation
circuit 21 for modulating a signal from the encoder 12A. The disc
production apparatus is also provided with: a spindle motor 16 for
rotating the glass substrate 14; a transfer unit 19 for transferring the
spindle motor 16," a transfer servo circuit 51 for
transfer-servo-controlling the transfer unit 19." and a position detector
52 for detecting a position of the transfer unit 19 and sending a
position signal to the transfer servo circuit 51. The disc production
apparatus is further provided with: a rotation servo circuit 18 for
rotation-servo-controlling the spindle motor 165 and a rotation detector
17 for detecting a rotation number of the spindle motor 16 and sending
a rotation signal to the rotation servo circuit 18.
In operation, the laser beam A is modulated by the light
modulator 11 so as to form the groove, on the basis of the land cutting
information sent from the encoder 12A. The laser beam B is
modulated by the light modulator 11 so as to form the land pre-pit.
The control procedures under the control of the controller 50 are
shown in FIG. 7 and FIG. 10 respectively.
The glass substrate 14 is set to the spindle motor 16. The
spindle motor 16 is rotated at a constant linear velocity (CLV) by
virtue of the rotation detector 17 and the rotation servo circuit 18.
The spindle motor 16 is transferable in the radial direction of the glass
substrate 14 by virtue of the transfer unit 19. The land portion is cut
in a spiral shape from the disc central side toward the disc outer
circumferential side on the resist surface of the glass substrate 14 by
controlling the transfer in the radial direction at a predetermined
transfer velocity by virtue of the position detector 52 and the transfer
servo circuit 51.
Next, the operation of the disc production apparatus to which
the signal recording method of the present invention is applied is
explained with reference to the flowchart of FIG. 7.
At first, the wobbled groove is formed by the laser beam A, and
the land pre-pit is formed by the laser beam B (step Si). Since the
portion where the information pit is to be formed in the lead in area is
the unreadable emboss area following the readable emboss area in the
control data zone, it is firstly judged whether or not it is the position to
form the readable emboss by the position detector 52 (step S72).
When arriving at the position to form the readable emboss in the
control data zone after passing the initial zone, the reference zone and
the buffer zone, the supply of the laser beam B is stopped so as to
temporarily stop recording the land pre-pit (step S72). Then, the
physical sector number is set to "02F200"h, and the operation of
recording the readable emboss pit in the control data zone is started
(step S75). Here, by modulating the laser beam A, the control data is
recorded while forming the wobbled groove by the laser beam A. Also,
in order to form the deep readable emboss pit, the laser power of the
laser beam A is increased in the control data zone.
After the 192 ECC blocks are written by repeating the above
mentioned processes while sequentially updating the physical sector
number after the start address "02F200"h of the control data zone, it is
judged whether or not the position to form the unreadable emboss is
detected by the position detector 20 (step S76). When the-position to
form the unreadable emboss is detected by the position detector 20
(step S76: YES), the controller 50 sets the ECC block address of the
land pre-pit 4 forcedly to "002FA0"h and then restarts recording the
land pre-pit 4 (steps S77 and S78). Here, the formation of the land
pre-pit 4 is restarted by the laser beam B. Next, the unreadable
emboss pit is formed while wobbling it by the laser beam A in the
amount of 64 ECC blocks (step S79). Then, it is judged whether or
not the lead ECC block address "003000"h of the second buffer zone is
detected (step S80). When the lead ECC block address "003000"h of
the second buffer zone is detected (step S80- YES), the modulation of
the beam A is stopped, and the operation of recording the unreadable
emboss pit is ended (step S8l). After that, while forming the wobbled
groove by the laser beam A and forming the land pre-pit 4 by the laser
beam B again, the arrival at the end position i.e., the external
circumference is monitored (step S82). When finally arriving at the
external circumference, the pertinent processes are ended (step S82).
FIG. 9 is a diagram showing another embodiment of the lead
in area, and FIG. 10 is a flowchart showing the operation of the disc
production apparatus to realize this another embodiment. In FIG. 10,
the same steps as those in FIG. 7 carry the same step numbers,' and
the explanations thereof are omitted.
The difference between this embodiment shown in FIGs. 9 and
10 and the embodiment shown in FIG. 3 is that, while the unreadable
emboss area is allocated between the control data zone as the readable
emboss zone and the buffer zone following it (refer to the step S77 in
FIG. 7 etc.,) in the embodiment shown in FIG. 7, the unreadable
emboss area is allocated in the half of the buffer zone following the
control data zone (at a step S177 in FIG. 10) in the embodiment shown
in FIGs. 9 and 10.
In case that this unreadable emboss zone is 16 ECC blocks, it
is required to forcedly set the ECC block address "002FE0"h (at the
step S177) when the position to form the unreadable emboss is
detected (at the step S76). Other points of the embodiment shown in
FIGs. 9 and 10 are the same as those of the embodiment shown in FIG.
3, and the explanations thereof are omitted.
In addition, according to the present method shown in FIGs. 9
and 10, different from the embodiment shown in FIG. 3, it is not
necessary to perform a complicated address operation in order to
obtain the compatibility with the conventional DVD-RW version.
Therefore, as long as the writing and/or reading operation in the data
area is not interrupted, it is effective since the processing load for the
address control is reduced.
FIG. 11 is a diagram showing another embodiment of the lead
in area, and FIG. 12 is a flowchart showing the operation of the disc
production apparatus to realize this another embodiment. In FIG. 12,
the same steps as those in FIG. 9 carry the same step numbers, and
the explanations thereof are omitted.
The difference between this embodiment shown in FIGs. 11
and 12 and the embodiment shown in FIGs. 9 and 10 is that, while the
control data zone consisting of 192 ECC blocks is formed as the
readable emboss area and the front half 16 ECC blocks of the following
buffer zone consisting of 32 ECC blocks is formed as the unreadable
emboss area in the embodiment shown in FIGs. 9 and 10, the front 176
ECC blocks of the control data zone originally consisting of 192 ECC
blocks is formed as the readable emboss area and the rear 16 ECC
blocks are allocated as the unreadable emboss area in the embodiment
shown in FIGs. 11 and 12. Therefore, in the control data zone, the
control data consisting of 16 sectors is written repeatedly by 176 times,
and the buffer zone following the unreadable emboss area is 32 ECC
blocks as they are.
In case that this unreadable emboss zone is 16 ECC blocks, it
is required to forcedly set the ECC block address "002FDO"h (at the
step S277) when the position to form the unreadable emboss is
detected (at the step S76).
In addition, according to the present method shown in FIGs.
11 and 12, in the same manner as the embodiment shown in FIGs. 9
and 10 and different from the embodiment shown in FIG. 3, it is not
necessary to perform a complicated address operation in order to
obtain the compatibility with the conventional DVD-RW version.
Therefore, as long as the writing and/or reading operation in the data
area is not interrupted, it is effective since the processing load for the
address control is reduced.
As described above, according to the present embodiment, the
control data zone (consisting of the 192 ECC blocks) is formed as the
readable emboss, and the unreadable emboss area of the 64 ECC
blocks is allocated between this control data zone and the buffer zone,
which follows the control data zone and consists of the 32 ECC blocks.
Alternatively, the control data zone (consisting of the 192 ECC blocks)
is formed as the readable emboss, and the front half 16 ECC blocks of
the buffer zone, which follows the control data zone and consists of the
32 ECC blocks, is allocated as the unreadable emboss area. Further
alternatively, the front 176 ECC blocks of the control data zone
originally consisting of the 192 ECC blocks are formed as the readable
emboss, and the rear 16 ECC blocks are allocated as the unreadable
emboss area. Therefore, the data recording operation with respect to
the area immediately after the unreadable emboss area can be
performed. Also, the land pre-pit corresponding to the readable
emboss area is not recorded. Further, the address of the guide track
corresponding to the unreadable area is determined on the basis of the
lead address information of the guide signal corresponding to the data
area, so as to make the physical sector number coincide with that of
the conventional DVD-RW version.
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 the meaning and range
of equivalency of the claims are therefore intended to be embraced
therein.
The entire disclosures of Japanese Patent Applications
No.2000-0078102 filed on March 21, 2000 and NO.2000-38609 filed on
February 16, 2000 including the specification, claims, drawings and
summary is incorporated herein by reference in its entirety.
We claim:
1. An optical disc (1) comprising:
a recordable area (RIA, IA) comprising an information track (102, G) in which
an information signal is to be recorded;
a first emboss area in which first emboss pits array are formed; and
a second emboss area in which second emboss pits array are formed,
wherein the first emboss pits array have physically different structure from the
second emboss pits array.
2. An optical disc (1) as claimed in claim 1, wherein
the second emboss area is disposed immediately after the first emboss area.
3. An optical disc (1) as claimed in claim 1 or 2, wherein
the first emboss pits array have a different pit depth from the second emboss
pits array.
4. An optical disc (1) as claimed in claim 3, wherein
the first emboss pits array have a first depth, and
the second emboss pits array have a second depth which is shallower than the
first depth.
5. An optical disc (1) as claimed in any one of claims 1 to 4, wherein
the first emboss pits array and second emboss pits array are wobbled
respectively.
6. An optical disc (1) as claimed in any one of claims 1 to S, wherein
control data is recorded in the first emboss area as the first emboss pits array.
7. An optical disc (1) as claimed in any one of claims 1 to 6, wherein
dummy data is recorded in the second emboss area as the second emboss pits
array.
8. An optical disc (1) as claimed in any one of claims 1 to 7, wherein
each of the first emboss pits array and second emboss pits array has a size
which is an integral multiple of a size of an error correction unit.
9. An optical disc (1) as claimed in any one of claims 1 to 8, wherein
the first emboss area is larger than the second emboss area.
10. An optical disc (1) as claimed in claim 9, wherein
the first emboss area has Ml pieces of ECC blocks and the second emboss area
has M2 pieces of ECC blocks,
wherein the M2 is smaller number than the Ml.
11. An optical disc (1) as claimed in claim 9 or 10, wherein
the first emboss area is a readable emboss area and the second emboss area is
an unreadable emboss area.
12. An optical disc (1) as claimed in any one of claims 9 to 11, wherein
the disc comprises a lead-in area comprising at least an initial zone and a
control data zone and comprising a reference code zone, a first buffer zone and a second
buffer zone.
13. An optical disc (1) as claimed in claim (10), wherein
the number of Ml is equal to 176 and the number of M2 is equal to 16.
14. A method of producing an optical disc (1) comprising:
a recordable area (RIA, LA) forming process of forming a recordable area (RIA,
LA) comprising an information track (102, G) in which an information signal is to be
recorded;
a first emboss area forming process of forming a first emboss area in which
first emboss pits array are formed; and
a second emboss area forming process of forming a second emboss area in
which second emboss pits array are formed, which have physically different structure
from the first emboss pits array.
15. A method of producing an optical disc (1) as claimed in claim 14, wherein
the second emboss area forming process disposes the second emboss area
immediately after the first emboss area.
16. A method of producing an optical disc (1) as claimed in claim 14 or 15,
wherein
the first emboss pits array have a different pit depth from the second emboss
pits array.
17. A method of producing an optical disc (1) as claimed in claim 16, wherein
the first emboss pits array have a first depth, and
the second emboss pits array have a second depth which is shallower than the
first depth.
18. A method of producing an optical disc (1) as claimed in any one of claims 14 to
17, wherein
the first emboss pits array and second emboss pits array are wobbled
respectively.
19. A method of producing an optical disc (1) as claimed in any one of claims 14 to
18, wherein
control data is recorded in the first emboss area as the first emboss pits array.
20. A method of producing an optical disc (1) as claimed in any one of claims 14 to
19, wherein
dummy data is recorded in the second emboss area as the second emboss pits
array.
21. A method of producing an optical disc (1) as claimed in any one of claims 14 to
20, wherein
each of the first emboss pits array and second emboss pits array has a size
which is an integral multiple of a size of an error correction unit.
22. A method of producing an optical disc (1) as claimed in any one of claims 14 to
21, wherein
the first emboss area is larger than the second emboss area.
23. A method as claimed in claim 22, wherein
the first emboss area has Ml pieces of ECC blocks and the second emboss area
has M2 pieces of ECC blocks,
wherein the M2 is smaller number than the Ml.

24. A method as claimed in claim 22 or 23 wherein
the first emboss area is a readable emboss area and the second emboss area is
an unreadable emboss area.
25. A method as claimed in any one of claims 22 to 24, wherein
the disc comprises a lead-in area comprising at least an initial zone and a
control data zone and comprising a reference code zone, a first buffer zone and a second
buffer zone.
26. A method as claimed in claim 23, wherein
the number of Ml is equal to 176 and the number of M2 is equal to 16.
27. An apparatus for producing an optical disc (1) comprising:
a recordable area (RIA, LA) forming device for forming a recordable area (RIA,
LA) comprising an information track (102, G) in which an information signal is to be
recorded;
a first emboss area forming device for forming a first emboss area in which
first emboss pits array are formed; and
a second emboss area forming device for forming a second emboss area in
which second emboss pits array are formed, which have physically different structure
from the first emboss pits array.
28. An apparatus for producing an optical disc (1) as claimed in claim 27, wherein
the second emboss area forming devices disposes the second emboss area
immediately after the first emboss area.
29. An apparatus for producing an optical disc (1) as claimed in claim 27 or 28,
wherein
the first emboss pits array have a different pit depth from the second emboss
pits array.
30. An apparatus for producing an optical disc (1) as claimed in claim 29, wherein
the first emboss pits array have a first depth, and
the second emboss pits array have a second depth which is shallower than the
first depth.
31. An apparatus for producing an optical disc (1) as claimed in any one of claims
27 to 30, wherein
the first emboss pits array and second emboss pits array are wobbled
respectively.
32. An apparatus for producing an optical disc (1) as claimed in any one of claims
27 to 31, wherein
control data is recorded in the first emboss area as the first emboss pits array.
33. An apparatus for producing an optical disc (1) as claimed in any one of claims
27 to 32, wherein
dummy data is recorded in the second emboss area as the second emboss pits
array.
34. An apparatus for producing an optical disc (1) as claimed in any one of claims
27 to 33, wherein
each of the first emboss pits array and second emboss array has a size which is
an integral multiple of a size of an error correction unit.
35. An apparatus for producing an optical disc (1) as claimed in any one of claims
27 to 34, wherein
the first emboss area is larger than the second emboss area.
36. An apparatus as claimed in claim 35, wherein
the first emboss area has Ml pieces of ECC blocks and the second emboss area
has M2 pieces of ECC blocks,
wherein the M2 is smaller number than the Ml.
37. An apparatus as claimed in claim 35 or 36 wherein
the first emboss area is a readable emboss area and the second emboss area is
an unreadable emboss area.
38. An apparatus as claimed in any one of claims 35 to 37, wherein
the disc comprises a lead-in area comprising at least an initial zone and a
control data zone and comprising a reference code zone, a first buffer zone and a second
buffer zone.
39. An apparatus as claimed in claim 36, wherein
the number of Ml is equal to 176 and the number of M2 is equal to 16.

This invention comprises an optical disc (1) provided with a recordable area (R1A, 1A) having an
information track (102, G) in which an information signal is to be recorded, a first emboss area
in which first emboss pits array are formed and a second emboss area in which second emboss
pits array are formed, wherein the first emboss pits array have physically different structure from
the second emboss pits array. The invention further provides a method and apparatus for
producing an optical disc (1).