U.S. patent application number 11/140277 was filed with the patent office on 2005-10-06 for phase change optical information recording medium, information recording method and apparatus therefor, and information erasing method therefor.
Invention is credited to Noda, Eiji.
Application Number | 20050219983 11/140277 |
Document ID | / |
Family ID | 27347566 |
Filed Date | 2005-10-06 |
United States Patent
Application |
20050219983 |
Kind Code |
A1 |
Noda, Eiji |
October 6, 2005 |
Phase change optical information recording medium, information
recording method and apparatus therefor, and information erasing
method therefor
Abstract
A phase change optical information recording medium including: a
substrate; and a recording layer which is located overlying the
substrate and in which marks are to be formed to store information,
wherein the substrate includes plural sessions including a first
session in which pits are formed and which includes a RAM region
including a groove and a wobble signal, and a program memory area
in which pits are formed and which includes position information of
the first session and does not include disc ID information of the
phase change optical information recording medium.
Inventors: |
Noda, Eiji; (Kawasaki-shi,
JP) |
Correspondence
Address: |
Christopher C. Dunham
c/o Cooper & Dunham LLP
1185 Ave. of the Americas
New York
NY
10036
US
|
Family ID: |
27347566 |
Appl. No.: |
11/140277 |
Filed: |
May 26, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11140277 |
May 26, 2005 |
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10256110 |
Sep 25, 2002 |
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Current U.S.
Class: |
369/59.11 ;
369/47.5; G9B/19.005; G9B/7.022; G9B/7.033; G9B/7.037;
G9B/7.142 |
Current CPC
Class: |
G11B 7/24082 20130101;
G11B 19/04 20130101; G11B 7/0079 20130101; G11B 2007/24316
20130101; G11B 2007/24314 20130101; G11B 7/00736 20130101; G11B
2007/24308 20130101; G11B 7/00557 20130101; G11B 7/006 20130101;
G11B 7/243 20130101; G11B 7/1267 20130101; G11B 2007/2431
20130101 |
Class at
Publication: |
369/059.11 ;
369/047.5 |
International
Class: |
G11B 005/09 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 25, 2001 |
JP |
2001-291047 |
Nov 19, 2001 |
JP |
2001-353386 |
Jan 30, 2002 |
JP |
2002-022482 |
Claims
1-7. (canceled)
8. An information recording apparatus comprising: receiving means
for receiving an order to record or erase information in a phase
change optical information recording medium; reading means for
reading a position of disc ID information stored in a program
memory area of the phase change optical information recording
medium and position information of plural sessions of the phase
change optical information recording medium; recording/erasing
means for recording and erasing information in the plural sessions;
and controlling means for controlling the recording/erasing means
to record or erase the information in one or more of the plural
sessions according to the order when the position information of
the one or more sessions is located after the disc ID information
in the program memory area, or refusing the order when the position
information of the one or more of the plural sessions located
before the disc ID information in the program memory area.
9. The information recording apparatus according to claim 8,
wherein the controlling means further has a function of ordering
the recording/erasing means to rewrite the disc ID information such
that the position of the ID information is changed to record and
erase the information in the one or more of the plural
sessions.
10. The information recording apparatus according to claim 8,
further comprising a memory storing session information concerning
recordable and erasable sessions, wherein the controlling means
further has a function of referring to the session information
stored in the memory when the receiving means receives an erasure
order for a last session of the plural sessions in the optical
information recording medium to determine whether or not the last
session is an erasable session, and ordering the recording/erasing
means to erase the last session when the last session is a
recordable and erasable session or refusing the erasure order when
the last session is not a recordable and erasable session.
11. The information recording apparatus according to claim 8,
further comprising a memory storing session information concerning
non-recordable and non-erasable sessions, wherein the controlling
means further has a function of referring to the session
information stored in the memory when the receiving means receives
a complete erasure order for the plural sessions in the phase
change optical information recording medium to determine whether or
not a non-recordable and non-erasable session is present in the
memory, and ordering the recording/erasing means to perform the
complete erasure order when a non-recordable and non-erasable
session is not present in the memory or refusing the complete
erasure order when a non-recordable and non-erasable session is
present in the memory.
12. An information recording apparatus which records information in
a phase change optical information recording medium including
plural sessions each including at least one of a ROM region not
including a wobble signal and a RAM region including a wobble
signal, comprising: receiving means for receiving an erasure order
for a session; judging means for checking whether a wobble signal
is present in the session to determine whether the session does not
include a ROM region; and erasing means for erasing the session
when the session does not include the ROM region.
13. A method for recording and erasing information in a phase
change optical information recording medium including a program
memory area and plural sessions, comprising: reading position
information of disc ID information on the program memory area and
position information of the plural sessions of the phase change
optical information recording medium; and recording and erasing
information in one or more of the plural sessions upon receiving of
an order to record or erase the information when the position
information of the one or more of the plural sessions is located
after the disc ID information, or refusing the order to record and
erase the information when the position information of the one or
more of the plural sessions is located before the disc ID
information.
14. The method according to claim 13, further comprising: rewriting
the disc ID information such that the position of the ID
information is changed to control recording and erasing of
information in the one or more of the plural sessions.
15. A method of recording information in a phase change optical
information recording medium including plural sessions each
including at least one of a ROM region not including a wobble
signal and a RAM region including a wobble signal, comprising:
checking whether a wobble signal is present in a session to
determine whether the session does not include a ROM region upon
receiving an erasure order for the session; and erasing the session
when the session does not include a ROM region.
16. A method for determining an optimum CW erasure power for
erasing information in a phase change information recording medium,
comprising: CW-erasing HF signals, which are recorded in the phase
change information recording medium with a fixed writing power
while changing an erasure power Pe; measuring a pit level I11L or
both the pit level I11L and a land level I11H of a remaining 11t
signal of the HF signals; determining the optimum CW erasure power
Pecw such that at least one of the following relationships (1) and
(2) is satisfied:Pe1+0.05.times..DELTA.Pecw.ltoreq.-
Pe2-0.05.times..DELTA.Pe (1)wherein Pe1 represents a Pe when
d(I11L)/d(Pe) is maximized, Pe2 represents a Pe when d(I11L)/d(Pe)
is minimized, and .DELTA. Pe represents Pe2-Pe1;
andI11L/I11H>0.8 (2).
17. The method according to claim 16, wherein the fixed writing
power is higher than an optimum writing power (Pwo) determined by a
.gamma. method.
18. The method according to claim 16, wherein the CW-erasing step
is performed at a linear speed of the phase change optical
information recording medium that is higher than a maximum
recording linear speed of the phase change optical information
recording medium.
19. A method of directly overwriting information in a phase change
optical information recording medium, comprising: recording
information in the phase change optical information recording
medium while erasing information stored in the phase change optical
information recording medium with an erasure power, wherein the
erasure power is the optimum CW erasure power determined by the
method according to claim 16.
20. A method of directly overwriting information in a phase change
optical information recording medium, comprising: first recording
information in the phase change optical information recording
medium by applying a writing power and an erasure power thereto to
record HF signals therein while the writing power is changed and
the erasure power is fixed; measuring a mark-length/pit-length
balance .beta. of the HF signals; determining an optimum writing
power such that the mark-length/pit-length balance .beta. is from 0
to 8%; and second recording information in the phase change optical
information recording medium while applying the optimum writing
power to the phase change optical information recording medium.
21. An information erasing method comprising: performing CW erasing
on a phase change optical information recording medium having a ROM
region formed by a stamper, by applying an erasure power thereto,
wherein the erasure power is determined by the CW erasure power
determination method according to claim 16.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an optical information
recording medium, and particularly to a rewritable phase-change
optical information recording medium for use as a CD-RW, DVD-RW,
DVD+RW, etc. In addition, the present invention relates to a
recording method and apparatus in which information is recorded in
the optical information recording medium. Further, the present
invention relates to an information recording method in which
information is overwritten in the optical information recording
medium. Furthermore, the present invention relates to an
information erasing method.
[0003] 2. Discussion of the Related Art
[0004] Conventional CD-RWs include a guide groove. As illustrated
in FIG. 8, the guide groove is wobbled because wobble signals are
recorded on entire the surface thereof in an irradiation process in
stamping.
[0005] The wobble signals include time (address) information called
ATIP (absolute time in pre-groove). ATIP is represented as, for
example, "00m00s00f", wherein m represents minute, s represents
second and f represents flame (i.e.,. {fraction (1/75)} second). In
an area located before the point 00m00s00f, a PMA (program memory
area) is present. In an area located between the PMA and the point
00m00s00f, "special information" and "additional information" which
are important information concerning record/reproduction of the
optical recording medium are recorded.
[0006] "Multi-session" is one of the file structures of rewritable
optical information recording media and means a structure in which
two or more sessions are recorded in an optical information
recording medium. Each session includes a lead-in area (hereinafter
sometimes referred to as a L/I or a L/I area) , a data area
(hereinafter sometimes referred to as a Data or a Data area) and a
lead-out area (hereinafter sometimes referred to as a L/O or a L/O
area).
[0007] FIGS. 1 and 2A-2F are schematic views illustrating data
arrangement in conventional CD-RWs.
[0008] FIG. 1 is a schematic view illustrating arrangement of
address data of a conventional CD-RW. Referring to FIG. 1, the area
of from a point of 98m13s50f to a point of 98m27s00f is a program
memory area (hereinafter sometimes referred to as a PMA). The area
of from a point of 98m27s00f to a point of 99m59s74f is a L/I area.
The area of from a point of 00m00s00f to a point of 75m42s00f is a
Data area.
[0009] FIG. 2A is a schematic view illustrating a state of a CD-RW
in which information is not recorded (i.e., a state of a CD-RW
which is not used).
[0010] FIG. 2B is a schematic view illustrating a state of the
CD-RW, in whicb a first session (i. e. , L/T-1, Data-1 and L/O-1)
is recorded in the CD-RW illustrated in FIG. 2A. In this case,
information of disc ID D and first session position information 1
are recorded in this order from the inside of the PMA.
[0011] FIG. 2C is a schematic view illustrating a state of the
CD-RW, in which a second session (i.e., L/I-2, Data-2 and L/O-2) is
recorded in the CD-RW illustrated in FIG. 2B. In this case, the
information of disc ID D, the first session information 1 and
second session position information are recorded in this order from
the inside of the PMA.
[0012] Information recorded in a phase change optical information
recording medium can be erased. For example, all information
recorded in a medium can be erased at once or only the last session
of multiple sessions of a medium can be erased. At this point,
erasure of information is performed by recording erasure
signals.
[0013] FIG. 2D is a schematic view illustrating a state of the
CD-RW, in which the last session (i.e., the second session) of the
CD-RW illustrated in FIG. 2C is erased.
[0014] FIG. 2E is a schematic view illustrating a state of the
CD-RW, in which the last session (i.e., the first session) of the
CD-RW illustrated in FIG. 2D is erased. This state is logically the
same as the state illustrated in FIG. 2A, however, they are
different because erasure signals are recorded in the CD-RW
illustrated in FIG. 2E whereas information is not recorded in the
CD-RW illustrated in FIG. 2A.
[0015] FIG. 2F is a schematic view illustrating a state of the
CD-RW in which all information is erased. This state is logically
the same as the state illustrated in FIG. 2A, however, they are
different because erasure signals are recorded in the CD-RW
illustrated in FIG. 2F.
[0016] Recently, recordable optical information recording media
having a ROM region, such as CD-Rs and CD-RWs, have been proposed.
As one of the recordable optical information recording media,
optical information recording media having a multi-session
structure in which the first session is a ROM region including pits
have been proposed.
[0017] A recording medium illustrated in FIGS. 3A to 3F is the same
as that illustrated in FIGS. 2A to 2E except that the first session
is a ROM region including pits.
[0018] FIG. 3A illustrates a CD-RW which is not used and which has
a ROM region in which signals (L/I-1, Data-1 and L/O-1) are
recorded by pits.
[0019] In the ROM region, pits and the groove formed between the
pits are wobbled as illustrated in FIG. 9 to obtain wobble signals
similarly to the signals in the RAM region.
[0020] FIG. 3B illustrates a state of the CD-RW, in which a second
session (i.e., L/I-2, Data-2 and L/O-2) is recorded in the CD-RW
illustrated in FIG. 3A.
[0021] FIG. 3C illustrates a state of the CD-RW, in which the last
session (i.e., the second session) of the CD-RW illustrated in FIG.
3B is erased. This state is logically the same as the state
illustrated in FIG. 3A, however, they are different because erasure
signals are recorded in the CD-RW illustrated in FIG. 3C.
[0022] At this point, when the last session (i.e., the first
session) is erased, the CD-RW achieves the state illustrated in
FIG. 3D. In this case, since the signals recorded in the first
session and the ROM signals in the PMA are not erased and erasure
signals are recorded therein, the disc becomes incapable of
recording and reproducing information thereafter.
[0023] FIG. 3E illustrates a state in which all information is
erased. In this case, the disc also becomes incapable of recording
and reproducing information thereafter similarly to the disc
illustrated in FIG. 3D.
[0024] Thus, these media have drawbacks in that controlling of
recording and erasing is difficult, and erasure signals are
recorded in the ROM region by mistake, thereby making the media
incapable of recording or erasing information.
[0025] When performing direct overwriting on a phase change optical
information recording medium, information is recorded by allowing
the recording layer thereof to achieve an amorphous state and
information is erased by allowing the recording layer to achieve a
crystallized state. The strength of the reflection signals of the
recording layer achieving an amorphous state is called a pit level,
and the strength of the reflection signals of the recording layer
achieving a crystallized state is called a land level.
[0026] Direct overwriting is conventionally performed on a phase
change optical information recording medium by applying a writing
power (Pw) which is determined according to a .gamma. method
described in the Orange Book and which depends on the drive used
and an erasure power (Pe) which is determined as a product of the
writing power (Pw) and a constant (.di-elect cons.).
[0027] According to this method, when the writing power (Pw) is
relatively high compared to the optimum value thereof, the erasure
power (Pe) also increases. Therefore the direct overwriting is
performed while applying an excessive erasure power and thereby the
recording layer tends to achieve an amorphous state, resulting in
decrease of the land level. Therefore, problems such that jitter
increases and durability of the recording layer deteriorates
occur.
[0028] In contrast, when the writing power (Pw) is relatively low
compared to the optimum value thereof, the erasure power (Pe) also
lowers, and thereby the previously recorded signals cannot be fully
erased. Therefore, a problem in that jitter increases occurs.
[0029] As another erasing method, a CW (or physical) erasure
method, in which erasure is performed by steady laser irradiation,
is described in the Orange Book. However, the optimum erasure power
(Peo), which is changed by the OPC (optimization of the writing
power) while depending on the optimum writing power (Pwo) which is
determined according to the .gamma. method described in the Orange
Book, is not proper for the CW erasure power (Pecw). Specifically,
the portion on which the CW erasure is performed has deteriorated
direct overwriting properties. Therefore, logical erasure methods
in which direct overwriting of erasure patterns is performed are
used for normal erasure.
[0030] In addition, hybrid discs which have a ROM region in a
portion thereof, which ROM region is formed by a stamper, will be
practically used shortly. When logical erasure is performed on the
hybrid discs, direct overwriting is performed on the ROM region
thereof, and thereby the hybrid discs become incapable of
reproducing information.
SUMMARY OF THE INVENTION
[0031] Accordingly, an object of the present invention is to
provide a rewritable phase change optical information recording
medium in which information is recorded and erased while the
recording and erasing are easily controlled (i.e., write protection
is easily performed).
[0032] Another object of the present invention is to provide a
rewritable phase change optical information recording medium in
which erasing signals are not recorded in the ROM region
thereof.
[0033] Yet another object of the present invention is to provide an
information recording (and reproducing) method and apparatus in
which information is recorded and erased while recording and
erasing are easily controlled (i.e., while write-protection is
easily performed).
[0034] A further object of the present invention is to provide an
information recording method and apparatus in which direct
overwriting is performed on an optical information recording medium
while determining an optimum CW erasure power.
[0035] A still further object of the present invention is to
provide an information erasing method by which information recorded
in a hybrid disc is securely erased.
[0036] To achieve such an object, the present invention
contemplates the provision of a phase change optical information
recording medium including: a substrate; and a recording layer
which is located overlying the substrate and in which marks are to
be formed to store information, wherein the substrate includes
plural sessions including a first session in which pits are formed
and which includes a RAM region including a groove and a wobble
signal, and a program memory area in which pits are formed and
which includes positional information of the first session and does
not include disc ID information of the phase change optical
information recording medium.
[0037] The first session of the optical information recording
medium further includes a ROM region including a data area
including no wobbling signal.
[0038] The recording medium preferably has a structure in which at
least a first dielectric layer, the recording layer, a second
dielectric layer, a reflection layer and an overcoat layer are
formed on one side the substrate in this order.
[0039] The recording layer preferably includes Ag, In, Sb and Te as
main components with respective atomic percents .alpha.,.beta.,
.gamma. and .delta. thereof being in the relationship of
.alpha.+.beta.+.gamma.+.delt- a.=100, 0<.alpha..ltoreq.10,
2.ltoreq..beta..ltoreq.12, 55.ltoreq..gamma..ltoreq.70 and 22
.ltoreq..delta..ltoreq.32.
[0040] Alternatively, the recording layer preferably includes Ge,
Ga, Sb and Te as main components with respective atomic percents
.alpha., .beta., .gamma. and .delta. thereof being in the
relationship of .alpha.+.beta.+.gamma.+.delta.=100,
0<.alpha.<.ltoreq.10, 1.ltoreq..beta..ltoreq.12, 55
.ltoreq..gamma.85 and 12 .ltoreq..delta..ltoreq.32.
[0041] The recording layer preferably further includes at least one
element selected from the group consisting of 3B group elements, 4B
group elements and 5B group elements in an amount not greater than
5 atomic %.
[0042] In another aspect of the present invention, an information
recording apparatus is provided which includes:
[0043] receiving means for receiving an order to record or erase
information in a phase change optical information recording
medium;
[0044] reading means for reading a position of disc ID information
stored in a program memory area of the phase change optical
information recording medium and position information of plural
sessions of the phase change optical information recording
medium;
[0045] recording/erasing means for recording and erasing
information in the plural sessions; and
[0046] controlling means for controlling the recording/erasing
means to record or erase the information in one or more of the
plural sessions according to the order when the position
information of the one or more sessions is located after the disc
ID information in the program memory area, or refusing the order
when the position information of the one or more of the plural
sessions located before the disc ID information in the program
memory area.
[0047] The controlling means may further have a function of
ordering the recording/erasing means to rewrite the disc ID
information such that the position of the ID information is changed
to record and erase the information in the one or more of the
plural sessions.
[0048] It is preferable that the information recording apparatus
preferably includes a memory storing session information concerning
recordable and erasable sessions, and the controlling means further
has a function of referring to the session information when the
receiving means receives an erasure order for a last session of the
plural sessions in the optical information recording medium to
determine whether or not the last session is an erasable session,
and ordering the recording/erasing means to erase the last session
when the last session is a recordable and erasable session or
refusing the erasure order when the last session is not a
recordable and erasable session.
[0049] It is preferable that the memory stores session information
concerning non-recordable and non-erasable sessions, and the
controlling means further have a function of referring to the
session information stored in the memory when the receiving means
receives a complete erasure order for the plural sessions in the
phase change optical information recording medium to determine
whether or not a non-recordable and non-erasable session is present
in the memory, and ordering the recording/erasing means to perform
the complete erasure order when a non-recordable and non-erasable
session is not present in the memory or refusing the complete
erasure order when a non-recordable and non-erasable session is
present in the memory.
[0050] In yet another aspect of the present invention, an
information recording apparatus is provided which records
information in a phase change optical information recording medium
including plural sessions each including at least one of a ROM
region not including a wobble signal and a RAM region including a
wobble signal and which includes:
[0051] receiving means for receiving an erasure order for a
session;
[0052] judging means for checking whether a wobble signal is
present in the session to determine whether the session does not
include a ROM region; and
[0053] erasing means for erasing the session when the session does
not include a ROM region.
[0054] In a further aspect of the present invention, an information
recording/erasing method is provided in which information is
recorded and erased in a phase change optical information recording
medium including a program memory area and plural sessions and
which includes the steps of:
[0055] reading position information of disc ID information on the
program memory area and position information of the plural sessions
of the phase change optical information recording medium; and
[0056] recording and erasing information in one or more of the
plural sessions upon receiving of an order to record or erase the
information when the position information of the one or more of the
plural sessions is located after the disc ID information, or
refusing the order to record and erase the information when the
position information of the one or more of the plural sessions is
located before the disc ID information.
[0057] The method preferably further includes rewriting the disc ID
information such that the position of the ID information is changed
to control recording and erasing of information in the one or more
of the plural sessions.
[0058] In a still further aspect of the present invention, an
information recording method is provided in which information is
recorded in a phase change optical information recording medium
including plural sessions each including at least one of a ROM
region not including a wobble signal and a RAM region including a
wobble signal and which includes the steps of:
[0059] checking whether a wobble signal is present in a session to
determine whether the session does not include a ROM region upon
receiving an erasure order for the session; and
[0060] erasing the session when the session does not include a ROM
region.
[0061] In a still further aspect of the present invention, a method
for determining an optimum CW erasure power for erasing information
in a phase change information recording medium, is provided which
includes the steps of:
[0062] CW-erasing HF signals, which are recorded in the phase
chance information recording medium with a fixed writing power
while changing an erasure power Pe;
[0063] measuring a pit level I11L or both the pit level I11L and a
land level I11H of a remaining 11t signal of the HF signals;
[0064] determining the optimum CW erasure power Pecw such that the
following relationship (1) is satisfied:
Pe1+0.05.times..DELTA.Pe.ltoreq.Pecw.ltoreq.Pe2-0.05.times..DELTA.Pe
(1)
[0065] wherein Pe1 represents a Pe when d(I11L)/d(Pe) is maximized,
Pe2 represents a Pe when d(I11L)/d(Pe) is minimized, and .DELTA. Pe
represents Pe2-Pe1.
[0066] Alternatively, the optimum erasure power Pecw may be
determined such that the following relationship (2) is
satisfied:
I11L/I11H>0.8 (2).
[0067] In the method, the fixed writing power is preferably higher
than an optimum writing power (Pwo) determined by a .gamma. method.
In addition, the CW-erasing step is preferably performed at a
linear speed of the phase change optical information recording
medium that is higher than the maximum recording linear speed of
the phase change optical information recording medium.
[0068] In a still further aspect of the present invention, a method
of directly overwriting information in a phase change optical
information recording medium is provided which includes the step
of:
[0069] first recording information in the phase change optical
information recording medium by applying a writing power and an
erasure power thereto to record HF signals therein while the
writing power is changed and the erasure power is fixed;
[0070] measuring a mark-length/pit-length balance .beta. of the HF
signals;
[0071] determining an optimum writing power such that the
mark-length/pit-length balance .beta. is from 0 to 8%; and
[0072] second recording information in the phase change optical
information recording medium while applying the optimum writing
power to the phase change optical information recording medium.
[0073] In still further aspect of the present invention, an optical
information recording method is provided which includes the steps
of performing CW erasing on a phase change optical information
recording medium (a hybrid disc) having a ROM region formed by a
stamper, by applying an erasure power thereto, wherein the erasure
power is determined by the CW erasure power determination method
mentioned above.
[0074] These and other objects, features and advantages of the
present invention will become apparent upon consideration of the
following description of the preferred embodiments of the present
invention taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0075] FIG. 1 is a schematic view illustrating arrangement of
address data of a conventional CD-RW;
[0076] FIG. 2 is a schematic view illustrating a state of a
conventional CD-RW in which information is not recorded
[0077] FIG. 2B is a schematic view illustrating a state of the
CD-RW, in which a first session (i.e., L/I-1, Data-1 and L/O-1) is
recorded in the CD-RW illustrated in FIG. 2A;
[0078] FIG. 2C is a schematic view illustrating a state of the
CD-RW, in whichasecond session (i.e., L/I-2, Data-2 andL/O-2) is
recorded in the CD-RW illustrated in FIG. 2B;
[0079] FIG. 2D is a schematic view illustrating a state of the
CD-RW, in which the last session (i.e., the second session) of the
CD-RW illustrated in FIG. 2C is erased;
[0080] FIG. 2E is a schematic view illustrating a state of the
CD-RW, in which the last session (i.e., the first session) of the
CD-RW illustrated in FIG. 2D is erased;
[0081] FIG. 2F is a schematic view illustrating a state of the
CD-RW in which all information in one of the CDE-RW illustrated in
FIGS. 2B to 2E is erased;
[0082] FIG. 3A is a schematic view illustrating a state of the
CD-RW of Example 1 which has a ROM region and in which a first
session (i.e., L/I-1, Data-1 and L/O-1) is recorded by pits;
[0083] FIGS. 3B to 3E are schematic views illustrating the states
of the CD-RW having a ROM region, which correspond to the states of
the conventional CD-RW illustrated in FIGS. 2C to 2F;
[0084] FIG. 4 is a schematic view illustrating a CD-RW in which the
first session is write-protected;
[0085] FIG. 5 is a schematic view illustrating a CD-RW having a ROM
portion, in which the second session is write-protected;
[0086] FIG. 6 is a schematic view illustrating data in a first
session which do not have a wobble signal.
[0087] FIG. 7 is a flowchart for explaining erasing process of the
image recording method of the present invention;
[0088] FIG. 8 is a schematic view illustrating wobbled-guide
grooves;
[0089] FIG. 9 is a schematic view illustrating a state of an
optical information recording medium in which pits and inter-pit
grooves are formed while wobbled;
[0090] FIG. 10 is a schematic view illustrating an embodiment of
the information recording/reproducing apparatus of the present
invention;
[0091] FIG. 11 is a graph illustrating a relationship between an
erasure power and a residual signal level;
[0092] FIG. 12 is a graph illustrating a relationship between a
record power and .beta. (mark length/pit length balance of EFM
signals) and error;
[0093] FIG. 13 is a graph illustrating a relationship between a
record power and error after direct-overwriting is performed twice;
and
[0094] FIG. 14 is a graph illustrating a relationship between a
record power and error after direct-overwriting is performed 1,000
times.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0095] At first, the phase change optical information recording
medium (hereinafter sometimes referred to as the recording medium)
of the present invention will be explained in detail.
[0096] The recording medium of the present invention (in
particular, CD-RW) typically has a constitution in which a first
dielectric layer, a recording layer, a second dielectric layer, a
reflection layer made of a metal or a metal ally, and an overcoat
layer are formed on one side of a substrate having a guide groove.
More preferably, a print layer is formed on the overcoat layer and
a hard-coat layer is formed on the other side of the substrate.
[0097] The substrate is typically made of a material such as glass,
ceramics and resins.
[0098] Specific examples of the resins for use as the substrate
include polycarbonate resins, acrylic resins, epoxy resins,
polystyrene resins, acrylonitrile-styrene copolymers, polyethylene
resins, polypropylene resins, silicone resins, fluorine-containing
resins, ABS resins, and urethane resins. Among these resins,
polycarbonate resins and acrylic resins are preferable in view of
moldability, optical properties and cost.
[0099] The shape of the substrate is not limited to disc shapes
and, for example, card-form and sheet-form substrates can also be
used.
[0100] When the recording medium of the present invention is used
as a rewritable compact disc (CD-RW), the recording medium
preferably meets the following conditions:
[0101] (1) the width of the guide groove formed on the substrate is
from 0.25 to 0.65 .mu.m and preferably from 0.30 to 0.60 .mu.m, and
the depth thereof is from 150 to 550 .ANG. and preferably from 200
to 450 .ANG.;
[0102] (2) the width of the pits formed or the subtrate is from
0.25 to 0.80 .mu.m and preferably from 0.30 to 0.70 .mu.m, and the
depth thereof is from 650 to 1300 .ANG. and preferably from 800 to
1100 .ANG.; and
[0103] (3) the width of the inter-pit guide groove formed on the
substrate is from 0.25 to 0.80 m and preferably from 0.30to 0.60
.mu.m, and the depth thereof is from 150 to 550 .ANG. and
preferably from 200 to 450 .ANG..
[0104] The requisites for the phase change optical information
recording medium of the present invention are to have not only a
function of recording and erasing information but also a signal
reproduction stability and a long life. In order to fulfill such
requisites, the recording layer thereof preferably includes at
least Ag, In, Sb and Te as main elements with respective atomic
percents of .alpha., .beta., .gamma. and .delta. thereof being in
the relationship of a .alpha.+.beta.+.gamma.+.delta.=100,
0<.alpha..ltoreq.10, 2.ltoreq..beta..ltoreq.12,
55.ltoreq..gamma..ltoreq.70 and 22.ltoreq..delta.32.
[0105] When the contents of Ag, In and Sb exceed the upper limits
(i.e., 10, 12 and 70 atomic %, respectively), the reproduction
stability and life of signals recorded in the recording layer are
not satisfactory.
[0106] The content of Te influences on the recording linear speed
of the recording medium, and therefore the content is preferably
controlled to be in a range of from 22 to 32 atomic % even when the
thickness of the recording layer and the heat conductivity of the
other layers are properly controlled.
[0107] Deterioration of reproduction properties and life of
recorded signals is caused by crystallization of amorphous marks.
In order to improve the reproduction stability and life of recorded
signals (i.e., in order to prevent amorphous marks from
crystallizing), at least one element selected from the groups
consisting of 3B elements, 4B elements and 5B elements is
preferably included in the recording layer.
[0108] The reason therefor is not clear, but is considered to be
that such an element can be located in spaces of AgInSbTe and/or
can form a chemical bonding with AgInSbTe, and thereby the
crystallization of amorphous marks can be prevented. Therefore it
is effective to use an element having a small atomic diameter,
large chemical bonding with AgInSbTe and many bonding sites. From
this point of view, elements such as B, C, N, Si, Ge and Sn are
preferable.
[0109] The content of such an element in the recording layer is
preferably not greater than 5 atomic %. When the content is too
high, the recording/erasing characteristics of the AgInSbTe
recording layer deteriorate, and thereby a problem in that recorded
information cannot be fully erased occur.
[0110] In addition, recording is performed on the recording medium
of the present invention at a high linear speed, the recording
layer preferably includes at least Ge, Ga, Sb and Te as main
elements with respective atomic percents of .alpha., .beta.,
.gamma. and .delta. thereof being in the relationship of a
.alpha.+.beta.+.gamma.+.delta.=100, 0<.alpha..ltoreq.10,
1.ltoreq..beta..ltoreq.12, 55.ltoreq..gamma..ltoreq.85 and
12.ltoreq..delta..ltoreq.32.
[0111] When the contents of Ge, Ga and Sb exceed the upper limits
(i.e., 10, 12 and 85 atomic %) , the reproduction stability and
life of signals recorded therein are not satisfactory
[0112] The content of Te influences on the recording linear speed
of the recording medium, and therefore the content is preferably
controlled to be in a range of from 22 to 32 atomic % even when the
thickness of the recording layer and the heat conductivity of the
other layers are properly controlled.
[0113] Similarly to the AgInSbte recording layer, deterioration of
reproduction properties and life of recorded signals is caused by
crystallization of amorphous marks. In order to improve the
reproduction stability and life of recorded signals (i.e. , in
order to prevent amorphous marks from crystallizing) at least one
element selected from the groups consisting of 3B elements, 4B
elements and 5B elements is preferably included in the GeGaSbTe
recording layer.
[0114] The reason therefor is the same as mentioned above in the
AgInSbte recording layer.
[0115] The content of the additional element included in the
GeGaSbTe recording layer is preferably not greater than 5 atomic %
for the same reason as mentioned above in the AgInSbte recording
layer.
[0116] The recording layer preferably has a thickness of from 10 to
50 nm and more preferably from 12 to 30 nm. In view of initial
characteristics such as jitter, overwriting characteristics and
productivity, the thickness is even more preferably 14 to 25 nm.
When the recording layer is too thin, light absorption ability
thereof deteriorates. Therefore the recording layer does not
function. To the contrary, when the recording layer is too thick,
uniform phase change does not occur when high speed recording and
erasing are performed.
[0117] The recording layer can be prepared by a method such as
vapor-phase growth methods, e.g., vacuum vapor deposition methods,
sputtering methods, plasma CVD methods, light CVD methods, ion
plating methods, electron beam deposition methods, etc. Among these
methods, sputtering methods are preferable because the methods have
good productivity and the resultant film has good film
properties.
[0118] Suitable materials for use in the first and second
dielectric layers include metal oxides such as SiO, SiO.sub.2, ZnO,
SnO.sub.2, Al.sub.2O.sub.3, TiO.sub.2, In.sub.2O.sub.3, MgO and
ZrO.sub.2; nitrides such as Si.sub.3N.sub.4, A1N, TiN, BN and ZrN;
sulfides such as ZnS, In.sub.2S.sub.3 and TaS.sub.4; carbides such
as SiC, TaC, B4C, WC, TiC and ZrC; and diamond-like carbon. These
materials can be used alone or in combination.
[0119] In addition, the material used in the first and second
dielectric layers can include impurities if desired. Further, the
each of the layers can be a multi-layer type dielectric layer. The
first and second dielectric layers have a melting point higher than
that of the recording layer.
[0120] The first and second dielectric layers can also be prepared
by a method such as vapor-phase growth methods, e.g., vacuum vapor
deposition methods, sputtering methods, plasma CVD methods, light
CVD methods, ion plating methods, electron beam deposition methods,
etc. Among these methods, sputtering methods are preferable because
the methods have good productivity and the resultant film has good
film properties.
[0121] The thickness of the first dielectric layer largely
influences on the reflectance of the recording medium against light
having a wavelength of 650 nm, which is used for reproducing
information stored in a DVD. In order to impart a reflectance of
from 0.15 to 0.25 (specification of CD-RW) against light having a
wavelength of 780 nm or 650 nm to the recording medium, the first
dielectric layer preferably has a thickness of from 65 to 130
nm.
[0122] The second dielectric layer preferably has a thickness of
form 15 to 45 nm and more preferably from 20 to 40 nm. When the
second dielectric layer is too thin, the layer does not function as
a heat resistant protective layer and in addition the sensitivity
of the resultant recording medium deteriorates. In contrast, when
the second dielectric layer is too thick, a problem in that the
second dielectric layer releases from the recording layer
occurs.
[0123] Suitable materials for use in the reflection layer include
metals such as Al, Au, Ag, Cu and Ta, and metal alloys of the
metals. In addition, an element such as Cr, Ti, Si, Cu, Ag, Pd and
Ta can be added in the reflection layer. The reflection layer can
be prepared by a method such as vapor-phase growth methods, e.g.,
vacuum vapor deposition methods, sputtering methods, plasma CVD
methods, light CVD methods, ion plating methods, electron beam
deposition methods, etc.
[0124] The reflection layer preferably has a thickness of from 70
to 200 nm and more preferably from 100 to 160 nm.
[0125] In order to prevent oxidation of the reflection layer, an
overcoat layer is preferably formed on the reflection layer. The
overcoat layer is typically formed by spin coating an ultraviolet
crosslinking resin. The overcoat layer preferably has a thickness
of from 5 to 15 .mu.m. When the overcoat layer is too thin, the
error rate increases if a print layer is formed on the overcoat
layer. To the contrary, when the overcoat layer is too thick,
internal stress seriously increases, resulting in deterioration of
the mechanical characteristics of the resultant recording
medium.
[0126] The hard-coat layer is typically formed on the other side of
the substrate by spin coating an ultraviolet crosslinking resin.
The thickness of the hard-coat layer is preferably from 2 to 6
.mu.m. When the hard-coat layer is too thin, good abrasion
resistance cannot be imparted to the resultant recording medium. In
contrast, when the hard-coat layer is too thick, internal stress
seriously increases, resulting in deterioration of the mechanical
characteristics of the resultant recording medium.
[0127] The hard-coat layer preferably has a high hardness, i.e., a
pencil hardness not less than H, so as not to be scratched when
rubbed with a cloth. In addition, an electroconductive material can
be included therein to prevent the resultant recording medium from
charging or being dusted.
[0128] Then the method of determining a CW erase power will be
explained in detail.
[0129] FIG. 10 illustrates an information recording/reproducing
apparatus of the present invention which can record and reproduce
information in the phase change optical information recording
medium of the present invention.
[0130] Referring to FIG. 10, numeral 1 denotes an optical
information recording medium, i.e., the phase change optical
information recording medium of the present invention. The
recording medium 1 is rotated by a driving device including a
spindle motor 2. A laser driving circuit 4, which is light source
driving means, drives a light source including a laser diode. A
record/reproduction pickup 3 irradiates the recording medium 1 with
laser light, which is emitted by the laser diode via an optical
system (not shown) and which is an electromagnetic wave, to cause a
phase change in the recording layer of the recording medium 1.
[0131] When light irradiates the thus phase-changed recording layer
and the reflected light is received by the record/reproduction
pickup 3, the recorded information can be reproduced. A wave form
processing circuit 6 measures the signal level of the reproduced HF
signals to determine the optimum CW erase power (Pecw) and optimum
writing power (Pwo)
[0132] The optimum writing power of the record/reproduction pickup
3 is set by a writing-power/erasure-power setting circuit 5.
[0133] The information recording/reproducing apparatus irradiates
the recording medium 1 with laser light serving as an
electromagnetic wave to cause a phase change in the recording layer
of the recording medium 1, resulting in recording or reproducing of
information therein of rewriting of information. The apparatus
includes a recording device which includes the record/reproduction
pickup 3 and a modulator which modulates signals to be
recorded.
[0134] The recording device including the pickup 3 performs PWM
recording on the recording layer of the recording medium 1, in
which signals are recorded by forming marks while changing the
width of the marks. When recording is performed, signals to be
recorded are modulated by the modulator using a clock. Suitable
modulation methods include Eight-to-Fourteen-Modulation (EFM)
methods, modified modulation methods of the EFM methods, etc.
[0135] FIG. 11 illustrates a relationship between an erasure power
(Pe) and a land level (I11H), a pit level (I11L) and d(I11L)/d(Pe)
of the residual signal 11T when signals are recorded in an
initialized phase change optical information recording medium and
the recorded signals are erased by a CW method. As can be
understood from the graph, when the value d(I11L)/d(Pe) is maximum,
the CW erasure power (Pe1) is 6.0 mW, and when the value
d(I11L)/d(Pe) is minimum, the CW erasure power (Pe2) is 10.2 mW.
The difference (.DELTA.Pe) (i.e., Pe2-Pe1) is 4.2 mW.
[0136] At this point, the optimum CW erase power (Pecw) is defined
as a power at which the resultant recording medium has a small
residual signal amplitude and a small reflectance decrease. In the
case of this phase change optical information recording medium, the
optimum CW erasure power (Pecw) ranges from 6.2 to 10.0 mW.
[0137] In order to measure the residual signal amplitude, the HF
signals are preferably recorded at a power greater than the optimum
writing power (Pwo) which is determined by a .gamma. method such
that the resultant signals tend to remain even when erased. When
the optimum CW erasure power (Pecw) is determined by such a method,
signals having a large signal amplitude can be well erased by
applying the optimum CW erasure power.
[0138] From the results mentioned above, the following relationship
can be obtained.
Pe1+0.05.times..DELTA.Pe.ltoreq.Pecw.ltoreq.Pe2-0.05.times..DELTA.Pe
[0139] When calculating to one places of decimals by rounding in
view of effective digits, the relationship is as follows:
6.2.ltoreq.Pecw.ltoreq.10.0.
[0140] In view of efficient use of a laser diode (LD), the smaller
the optimum CW erasure power (Pecw), the better the efficiency.
Therefore, in the case of this phase change optical information
recording medium, the optimum CW erasure power (Pecw) is 6.2
mW.
[0141] By applying such an erasure power, the land level (I11H) and
pit level (I11L) satisfy the following relationship:
I11L/I11H>0.8.
[0142] When a CW erase method is used, erasure can be performed at
a relatively high linear speed compared to direct overwrite methods
in which marks have to be formed while erasure is performed, and
erasure can be performed at a higher speed than that in logical
erasing.
[0143] FIG. 12 illustrates a relationship between .beta. and a
writing power (Pw) when signals are recorded at an erasure power
(Pe) of 6.2 mW (i.e., at the optimum erasure power (Pecw)). At this
point, .beta. represents a balance of mark length and pit length.
When .beta. ranges from 0 to 8%, errors hardly occur.
[0144] As can be understood from the graph in FIG. 12, when Pe is
fixed, .beta. and Pw have a primary correlation, and therefore
linearization can be used. It can be understood from the graph that
when Pw is 12.3 mW, .beta. is 4%, and therefore well-balanced EFM
signals can be obtained.
[0145] FIGS. 13 and 14 illustrate relationships between a record
power and a power margin of error in both a case in which direct
overwriting is repeated at an erasure power of 6.2 mW (i.e., the
method of the present invention) and a case in which direct
overwriting is repeated at an erasure power of .di-elect
cons..times.Pw(.di-elect cons.=0. 5) (i.e., a conventional method).
FIGS. 13 and 14 illustrate data when the direct overwriting is
repeated twice and 1000 times, respectively.
[0146] As can be understood from FIGS. 13 and 14, when Pe is 6.2
mW, the power margin, which is one of the direct overwrite
characteristics, is dramatically increased. Namely, it is
advantageous to fix the erasure power (Peo) in order to perform
highly reliable recording.
[0147] When a hybrid disc which includes a ROM region which is
formed by a stamper is subjected to logical erasing, direct
overwriting is performed on the ROM region. In this case, the ROM
region is not erased and a logical erase pattern is overwritten in
the ROM region, and thereby the ROM becomes impotent. In the thus
mistakenly erased hybrid disc, by erasing only the logical erase
pattern which is overwritten in the ROM region by the CW erasing
method, the ROM region can be restored.
[0148] Having generally described this invention, further
understanding can be obtained by reference to certain specific
examples which are provided herein for the purpose of illustration
only and are not intended to be limiting.
EXAMPLES
Example 1
[0149] FIGS. 3A-3E are schematic views illustrating arrangement of
information in the CD-RW having a ROM portion of the present
invention.
[0150] FIG. 3A is a schematic view illustrating the CD-RW in a
blank state. The following information has been recorded therein by
pits.
[0151] (1) the position information of the first session located in
an area of from 98m13s50f to 98m13s59f;
[0152] (2) the lead-in (L/I) area of the first session located in
the area of from 98m27s00f to 99m59s74f;
[0153] (3) the data (Data) area of the first session located in the
area of from 00m00s00f to 04m59s74f; and
[0154] (4) the lead-out (L/O) area of the first session located in
the area of from 05m00s00f to 06m29s74f.
[0155] In the CD-RW as illustrated in FIG. 3B, the following
information of the second session is additionally recorded:
[0156] (1) the disc ID information located in the area of from
98m13s50f to 98m13s69f;
[0157] (2) the position information of the second session in the
area located in the area of from 98m13s70f to 98m14s04f; and
[0158] (3) the L/I-2, Data-2 and L/O-2 areas of the second session
located in an area after the point 06m30s00f.
[0159] The CD-RW as illustrated in FIG. 3C achieves a state in
which the final session (i.e., the second session) of the CD-RW is
erased.
[0160] In this case, in the program memory area (PMA), the
following information is recorded from the inside thereof:
[0161] (1) the position information of the first session located in
the area of from 98m13s50f to 98m13s59f; and
[0162] (2) the disc ID information is recorded in the area located
in the area of from 98m13s60f to 98m13s69f.
[0163] FIG. 3D illustrates a state of the CD-RW, in which the disc
ID information is erased in the CD-RW illustrated in 3C. Even when
an order to erase the first session of the CD-RW in this state is
made, the first session and its position information thereof remain
without being erased because the position information of the first
session is located before the position of the disc ID
information.
[0164] FIG. 3E illustrates a state of the CD-RW in which all are
erased except the first session and its position information. The
reason why the first session and its position information are not
erased is the same as that mentioned above.
[0165] In the information recording method and apparatus of the
present invention, the PMA is read when the disc is mounted
therein. A session whose position information is located after the
disc ID information is regarded as a recordable and erasable
session. Other sessions are regarded as a non-recordable and
non-erasable session. This information is stored in a memory of the
apparatus.
[0166] Namely, in any states as illustrated in FIGS. 3A-3E, the
disc ID information is not located before the position information
of the first session, the first session is not a recordable and
erasable session, and therefore the first session is recorded in
the memory as a non-recordable and non-erasable session (i.e., a
write-protected session).
[0167] Then the write-protect method performed in the information
recording/reproducing apparatus will be explained.
[0168] Referring to FIG. 2C, the following information is recorded
in the PMA of the CD-RW:
[0169] (1) the disc ID information located in the area of from
98m13s50f to 98m13s59f; (2) the position information of the first
session located in the area of from 98m13s60f to 98m13s69f; and (3)
the position information of the second session located in the area
of from 98m13s70f to 98m14s04f.
[0170] However, the first and second sessions are not
write-protected (i.e., not protected against writing).
[0171] When the first session is desired to be write-protected,
information is re-recorded in the SMA area such that:
[0172] (1) the position information of the first session is located
in the area of from 98m13s50f to 98m13s59f; (2) the disc ID
information is located in the area of from 98m13s60f to 98m13s69f;
and (3) the position information of the second session is located
in the area of from 98m13s70f to 98m14s04f.
[0173] This state is illustrated in FIG. 4. Then the disc is
re-mounted. The position information of the second session is not
changed, and therefore the position information of the second
session may not be re-recorded.
[0174] As a result, the position information of the first session
is located before the disc ID information, and therefore the first
session becomes a non-recordable and non-erasable session.
[0175] Referring to FIG. 3C, the following information is recorded
in the PMA of the CD-RW: (1) the position information of the first
session located in the area of from 98m13s50f to 98m13s59f; (2) the
disc ID information located in the area of from 98m13s60f to
98m13s69f; and (3) the position information of the second session
located in the area of from 98m13s70f to 98m14s04f.
[0176] However, the second session is not write-protected.
[0177] When the second session is desired to be write-protected,
information is re-recorded in the SMA area such that:
[0178] (1) the position information of the second session is
located in the area of from 98m13s60f to 98m13s69f; and
[0179] (2) the disc ID information is located in the area of from
98m13s70f to 98m14s04f.
[0180] This state is illustrated in FIG. 5. Then the disc is
re-mounted.
[0181] In this case, since the first session is write-protected,
recording and erasing for the area of from 98m13s50f to 98m13s59f
is inhibited. Therefore the first session is not re-recorded.
[0182] As a result, the position information of the second session
is located before the disc ID information, and therefore the second
session becomes a non-recordable and non-erasable session.
[0183] When an order to erase the last session is received from a
host (such as computers and software), the information
recording/reproducing apparatus erases the last session if the last
session is the recordable and erasable session which is stored in
the memory of the apparatus. Otherwise, the apparatus answers the
host that the order is refused.
[0184] When an order to perform complete erasure (or quick erasure)
is received, the apparatus performs the complete erasure if there
is no non-recordable and non-erasable session in the memory of the
apparatus. Otherwise, the apparatus answers the host that the
complete erasure order is refused.
Example 2
[0185] A phase change optical information recording medium of the
present invention was prepared. The recording medium includes a PMA
of the first session at a position of 98m13s50f, which has a wobble
signal; a L/I area of the first session at a position ranging from
98m27s00f to 99m59s74f, which has a wobble signal as illustrated in
FIG. 9; a Data area of the first session at a position ranging from
00m00s00f to 04m59s74f, which does not have a wobble signal as
illustrated in FIG. 6; and a L/O area of the first session at a
position ranging from 05m00s00f to 06m29s74f, which has a wobble
signal as illustrated in FIG. 9. The PMA and L/I, Data and L/O
areas are formed of pits. In other areas, a guide groove having a
wobble signal is formed on a substrate. Thus, a CD-RW including
ATIP information was prepared.
[0186] As mentioned above, at least the first session including
pits is formed on the substrate. Namely, the first session includes
a ROM area which does not include a wobble signal and a RAM area
which includes a wobble signal. Therefore, the ROM area and RAM
area can be identified by checking whether a wobble signal in
present therein.
[0187] The optical information recording/reproducing apparatus of
the present invention includes a judging device B which is
illustrated in FIG. 7. The judging device B judges that a data area
of a session of a recording medium is a ROM when the session does
not include a wobble signal. When the data area of the session
includes a wobble signal, the judging device B judges that the
session is a RAM. The apparatus also includes a receiving device A
which is also illustrated in FIG. 7. When the receiving device A
receives an order to erase a session of a recording medium, the
recording/reproducing apparatus erases the session when the session
only includes a RAM (i e., the session does not include a ROM).
[0188] FIG. 7 is a flowchart illustrating an erasure operation of
the optical information recording/reproducing apparatus of the
present invention.
[0189] When the receiving device receives an order to erase a last
session from a host such as computers and software (step S1), the
recording/reproducing apparatus checks the PMA of a recording
medium to determine the position of the last session (steps S2 and
S3).
[0190] Then the recording/reproducing apparatus checks the data
area of the last session (i.e., Data-2 in FIG. 2C, and Data-1 in
FIG. 2B or 2D) (step S4) to read a wobble signal (i.e., ATIP
information) in the data area (step S5).
[0191] When a wobble signal is present in the data area (step S6,
Yes), the judging device B judges that the last session is not a
ROM and the recording/reproducing apparatus erases the last session
(step S7). To the contrary, when a wobble signal is not present in
the data area (step S6, No), the judging device B judges that the
last session is a ROM and the recording/reproducing apparatus
answers the host that the last session cannot be erased (step
S8).
[0192] When the receiving device A receives a complete erasure
order (i.e., a quick erasure-order) from a host, the
recording/reproducing apparatus checks PMA of a recording medium to
determine the position of the first session.
[0193] Then the recording/reproducing apparatus checks the data
area of the first session to read a wobble signal (i.e., ATIP
information) in the data area.
[0194] When a wobble signal is present in the data area, the
judging device B judges that the first session is not a ROM and the
recording/reproducing apparatus performs the complete erasure
(i.e., the quick erasure). To the contrary, when a wobble signal is
not present in the data area, the judging device B judges that the
first session is a ROM and the recording/reproducing apparatus
answers the host that the complete erasure cannot be performed.
[0195] Additional modifications and variations of the present
invention are possible in light of the above teachings. It is
therefore to be understood that within the scope of the appended
claims the invention may be practiced other than as specifically
described herein.
[0196] This document claims priority and contains subject matter
related to Japanese Patent Applications Nos. 2001-291047,
2001-353386 and 2002-022482, filed on Sep. 25, 2001, Nov. 19, 2001
and Jan. 30, 2002, the entire contents of which are herein
incorporated by reference.
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