U.S. patent application number 10/734165 was filed with the patent office on 2004-07-01 for information-recording medium and method for producing the same.
This patent application is currently assigned to FUJI PHOTO FILM CO., LTD.. Invention is credited to Usami, Yoshihisa.
Application Number | 20040126534 10/734165 |
Document ID | / |
Family ID | 26556686 |
Filed Date | 2004-07-01 |
United States Patent
Application |
20040126534 |
Kind Code |
A1 |
Usami, Yoshihisa |
July 1, 2004 |
Information-recording medium and method for producing the same
Abstract
Disclosed is a method for producing an information-recording
medium comprising, on a substrate, a dye recording layer capable of
recording information, the method comprising the step of drying the
substrate formed with the dye recording layer by allowing clean air
to flow while rotating the substrate at a high speed; wherein an
intake for introducing the clean air is narrowed by arranging a lid
having a circular opening at a central portion, at an opening
disposed at an upper portion of an apparatus for rotating the
substrate at the high speed.
Inventors: |
Usami, Yoshihisa;
(Odawara-shi, JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
FUJI PHOTO FILM CO., LTD.
|
Family ID: |
26556686 |
Appl. No.: |
10/734165 |
Filed: |
December 15, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10734165 |
Dec 15, 2003 |
|
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09684634 |
Oct 10, 2000 |
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Current U.S.
Class: |
428/64.2 ;
264/1.33; 369/273; G9B/7.139; G9B/7.194 |
Current CPC
Class: |
B05C 11/08 20130101;
G11B 7/26 20130101; G11B 7/24 20130101; B05D 1/005 20130101; B05D
3/0406 20130101 |
Class at
Publication: |
428/064.2 ;
369/273; 264/001.33 |
International
Class: |
B29D 017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 7, 1999 |
JP |
11-287352 |
Oct 7, 1999 |
JP |
11-287387 |
Claims
What is claimed is:
1. An information-recording medium comprising, on a substrate, a
recording layer capable of recording information, wherein: said
recording layer is dried by rotating said substrate at a high speed
and allowing clean air to flow through an intake which is formed to
be narrow, toward said recording layer formed on said
substrate.
2. A method for producing an information-recording medium
comprising, on a substrate, a recording layer capable of recording
information, said method comprising the step of: drying said
recording layer by rotating said substrate at a high speed and
allowing clean air to flow toward said recording layer formed on
said substrate, wherein: an intake for introducing said clean air
is formed to be narrow.
3. The method for producing said information-recording medium
according to claim 2, wherein said intake is narrowed by putting a
lid having an opening at least at a central portion, on said intake
for introducing said clean air.
4. The method for producing said information-recording medium
according to claim 3, wherein said opening is formed to have a
wedge-shaped configuration.
5. The method for producing said information-recording medium
according to claim 3, wherein said opening is formed to have a
substantially rhombic configuration.
6. The method for producing said information-recording medium
according to claim 3, wherein said lid has a first opening which
has a large diameter disposed at a central portion, and it has a
plurality of second openings which have diameters gradually
decreased for those disposed in a direction toward an outer
circumference in which a central angle resides in a spacing
distance of not less than 10.degree..
7. The method for producing said information-recording medium
according to claim 3, wherein said lid is formed to have a
substantially conical configuration which has a diameter
continuously decreased downwardly, and it has an opening at a
central portion.
8. The method for producing said information-recording medium
according to claim 3, wherein said lid has an opening at a central
portion, and it has a plurality of fins which are formed at a lower
surface in which a central angle resides in a spacing distance of
not less than 10.degree..
9. An information-recording medium comprising, on a substrate, a
dye recording layer capable of recording information, wherein: said
information-recording medium is produced by constructing a
production line so that a relationship of n/m<2 is satisfied
provided that m represents a number of molding machine or machines
for molding said substrate, and n represents a number of dye
application mechanism or mechanisms for forming said dye recording
layer.
10. A method for producing an information-recording medium
comprising, on a substrate, a dye recording layer capable of
recording information, wherein: a production line is constructed so
that a relationship of n/m<2 is satisfied provided that m
represents a number of molding machine or machines for molding said
substrate, and n represents a number of dye application mechanism
or mechanisms for forming said dye recording layer.
11. The method for producing said information-recording medium
according to claim 10, wherein said production line is constructed
by installing one dye application mechanism for forming said dye
recording layer for one molding machine for molding said substrate.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an information-recording
medium having, on a substrate, a recording layer capable of
recording information, and a method for producing the same.
[0003] 2. Description of the Related Art
[0004] In general, the optical information-recording medium
(optical disk) capable of recording information only once by using
the laser beam includes, for example, write-once type CD (so-called
CD-R) and DVD-R. Such an optical information-recording medium is
advantageous in that a small amount of CD's can be commercially
supplied to the market quickly at a convenient price as compared
with the production of conventional CD (compact disk). The demand
for such an optical information-recording medium is increasing in
accordance with the recent popularization of personal computers or
the like.
[0005] The optical information-recording medium of the CD-R type
has a representative structure comprising a recording layer
composed of an organic dye, a light-reflective layer composed of a
metal such as gold, and a protective layer made of a resin which
are stacked in this order on a transparent disk-shaped substrate
having a thickness of about 1.2 mm (see, for example, Japanese
Laid-Open Patent Publication No. 6-150371).
[0006] The optical information-recording medium of the DVD-R type
has a structure comprising two disk-shaped substrates (having a
thickness of about 0.6 mm) which are laminated with each other with
respective information-recording surfaces disposed inwardly in an
opposing manner. The optical information-recording medium of this
type has such a feature that a large amount of information is
recorded thereon.
[0007] Information is written (recorded) on the optical
information-recording medium by radiating a near infrared laser
beam (laser beam usually having a wavelength of about 780 nm in the
case of CD-R or a wavelength of about 635 nm in the case of DVD-R).
A portion of the dye recording layer, which is irradiated with the
laser beam, absorbs the light, and its temperature is locally
raised. As a result, a physical or chemical change (for example,
generation of pit) takes place, and the optical characteristic is
changed. Thus, the information is recorded.
[0008] On the other hand, information is also read (reproduced) by
radiating a laser beam usually having the same wavelength as that
of the recording laser beam. The information is reproduced by
detecting the difference in reflectance between a portion (recorded
portion based on the generation of pit) which has subjected to the
change in optical characteristic of the dye recording layer and a
portion (non-recorded portion) which is not subjected to the
change.
[0009] In general, the disk-shaped optical information-recording
medium, on which the information signal is recorded and reproduced
by the aid of the light beam, includes read-only type optical disks
referred to as so-called compact disk, write-once type optical
disks capable of recording only once, and rewritable optical disks
capable of not only reproduction but also recording and erasing of
the information signal.
[0010] Polycarbonate resin or acrylic resin is generally used as a
material for the substrate for the optical disk as described above.
In view of the productivity, the substrate is produced by using the
injection molding method or the injection compression molding
method. After the molding treatment is applied, the substrate is
cooled, and it is transported to the dye recording layer-forming
step.
[0011] In the method for producing the optical
information-recording medium as described above, when the recording
layer based on the organic dye is formed on the substrate, the dye
solution is applied onto the substrate while rotating the
substrate. After the dye solution is applied, the clean air is
allowed to flow toward the recording layer while rotating the
substrate at a high speed so that the recording layer is dried.
[0012] In this case, when the intake for introducing the clean air
is wide, a larger amount of clean air flows toward the outer
circumferential portion of the recording layer as compared with the
inner circumferential portion thereof. For this reason, the outer
circumferential portion is dried without sufficiently blowing off
the excessive dye solution, as compared with the inner
circumferential portion. As a result, a problem arises such that
the film thickness is non-uniform between the outer circumferential
portion and the inner circumferential portion, and the recording
characteristic is deteriorated.
[0013] In order to improve the throughput of the
information-recording medium, the drying time is shortened by
increasing the environmental temperature for drying the recording
layer or the temperature of the substrate itself, rotating the
substrate at a higher speed by increasing the concentration of the
dye solution, or increasing the air blow speed during the drying.
However, the method as described above involves such a problem that
the running cost is expensive.
[0014] In the method for producing the optical
information-recording medium as described above, two or more dye
application mechanisms for forming the dye recording layer are
installed for one molding machine for molding the substrate. That
is, when two or more substrate-molding machines are installed, four
or more dye application mechanisms are installed. The dye recording
layer is hitherto formed with a plurality of production lines. For
this reason, the maintenance cost for the respective equipments is
expensive, and the quality control for each of the production lines
is complicated, resulting in the large scale of the production
equipment, and the enlargement of the installation space. In
accordance therewith, it is feared that the price of the optical
information-recording medium to be produced may become high, and
the yield may be lowered.
SUMMARY OF THE INVENTION
[0015] The present invention has been made taking the foregoing
problems into consideration, an object of which is to provide an
information-recording medium and a method for producing the same
which make it possible to reduce the drying time for a recording
layer, obtain a uniform film thickness of the recording layer, and
improve the throughput for the information-recording medium at low
cost.
[0016] Another object of the present invention is to provide an
information-recording medium and a method for producing the same
which make it possible simplify the production line by satisfying a
relationship of n/m<2 provided that m represents the number of
substrate-molding machine or machines and n represents the number
of dye application mechanism or mechanisms for forming a dye
recording layer wherein the quality control is easily performed and
the maintenance cost is reduced, making it possible to realize a
small scale of the production equipment and reduce the installation
space so that the low price of the information-recording medium
produced thereby may be realized and the improvement in yield may
be achieved.
[0017] According to the present invention, there is provided an
information-recording medium comprising, on a substrate, a
recording layer capable of recording information; wherein the
recording layer is dried by rotating the substrate at a high speed
and allowing clean air to flow through an intake which is formed to
be narrow, toward the recording layer formed on the substrate.
[0018] According to another aspect of the present invention, there
is provided a method for producing an information-recording medium
comprising, on a substrate,a recording layer capable of recording
information, the method comprising the step of drying the recording
layer by rotating the substrate at a high speed and allowing clean
air to flow toward the recording layer formed on the substrate;
wherein an intake for introducing the clean air is formed to be
narrow.
[0019] In the method for producing the information-recording medium
described above, it is also preferable that the intake is narrowed
by arranging a disk-shaped lid having an opening at least at a
central portion, on the intake for introducing the clean air.
Alternatively, the opening may have a wedge-shaped configuration or
a substantially rhombic configuration.
[0020] It is also preferable that the lid has a first opening which
has a large diameter disposed at a central portion, and it has a
plurality of second openings which have diameters gradually
decreased for those disposed in a direction toward an outer
circumference in which a central angle resides in a spacing
distance of not less than 10.degree..
[0021] It is also preferable that the lid is formed to have a
substantially conical configuration which has a diameter
continuously decreased downwardly, and it has an opening at a
central portion. Alternatively, the lid may have a plurality of
fins which are formed at a lower surface in which a central angle
resides in a spacing distance of not less than 10.degree..
[0022] Accordingly, the clean air can be allowed to flow toward the
entire surface of the recording layer substantially uniformly.
Therefore, the recording layer can be dried uniformly concerning
the planar direction and the film thickness direction of the
recording layer. Thus, it is possible to produce the
information-recording medium having good recording
characteristics.
[0023] Further, the drying time for the recording layer can be
shortened without increasing the environmental temperature for
drying the recording layer or the temperature of the substrate
itself, without rotating the substrate at a higher speed by
increasing the concentration of the dye solution, or without
increasing the air blow speed during the drying. Therefore, it is
possible to remarkably suppress the increase in running cost.
Further, it is possible to improve the throughput of the
information-recording medium.
[0024] According to still another aspect of the present invention,
there is provided an information-recording medium comprising, on a
substrate, a dye recording layer capable of recording information;
wherein the information-recording medium is produced by
constructing a production line so that a relationship of n/m<2
is satisfied provided that m represents a number of molding machine
or machines for molding the substrate, and n represents a number of
dye application mechanism or mechanisms for forming the dye
recording layer.
[0025] According to still another aspect of the present invention,
there is provided a method for producing an information-recording
medium comprising, on a substrate, a dye recording layer capable of
recording information; wherein a production line is constructed so
that a relationship of n/m<2 is satisfied provided that m
represents a number of molding machine or machines for molding the
substrate, and n represents a number of dye application mechanism
or mechanisms for forming the dye recording layer. In this aspect,
it is preferable that the production line is constructed by
installing one dye application mechanism for forming the dye
recording layer for one molding machine for molding the
substrate.
[0026] Accordingly, it is possible to simplify the production line,
and it is easy to perform the quality control for each production
line. Further, the maintenance cost for each equipment can be
reduced, making it possible to realize a small scale of the
production equipment and reduce the installation space. Therefore,
it is possible to realize the low price of the
information-recording medium produced thereby, and it is possible
to achieve the improvement in yield.
[0027] The above and other objects, features, and advantages of the
present invention will become more apparent from the following
description when taken in conjunction with the accompanying
drawings in which a preferred embodiment of the present invention
is shown by way of illustrative example.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 shows an arrangement of an exemplary production
system according to a first embodiment;
[0029] FIG. 2 shows an arrangement of a spin coat apparatus
installed in an application equipment;
[0030] FIG. 3 shows a perspective view illustrating the spin coat
apparatus;
[0031] FIG. 4 shows a lateral sectional view illustrating a state
in which a lid is arranged on an opening of the spin coat
apparatus;
[0032] FIG. 5 shows a perspective view illustrating an application
solution-drying apparatus installed for a substrate-drying
mechanism;
[0033] FIG. 6A shows an upper surface of the lid used in the first
embodiment, and FIG. 6B shows a sectional view taken along a line
VI-VI;
[0034] FIG. 7A shows an upper surface of a lid according to a first
modified embodiment, and FIG. 7B shows a sectional view taken along
a line VII-VII;
[0035] FIG. 8A shows an upper surface of a lid according to a
second modified embodiment, and FIG. 8B shows a sectional view
taken along a line VIII-VIII;
[0036] FIG. 9A shows an upper surface of a lid according to a third
modified embodiment, and FIG. 9B shows a sectional view taken along
a line IX-IX;
[0037] FIG. 10A shows an upper surface of a lid according to a
fourth modified embodiment, and FIG. 10B shows a sectional view
taken along a line X-X;
[0038] FIG. 11A shows an upper surface of a lid according to a
fifth modified embodiment, and FIG. 11B shows a sectional view
taken along a line XI-XI;
[0039] FIG. 12A shows an upper surface of a lid according to a
sixth modified embodiment, and FIG. 12B shows a sectional view
taken along a line XII-XII;
[0040] FIG. 13 shows a plan view illustrating a nozzle of the spin
coat apparatus;
[0041] FIG. 14 shows a side view illustrating the exemplary
nozzle;
[0042] FIG. 15 shows, with partial omission, a magnified side view
illustrating another exemplary nozzle;
[0043] FIG. 16A shows a production step illustrating a state in
which a groove is formed on a substrate, FIG. 16B shows a
production step illustrating a state in which a dye recording layer
is formed on the substrate, and FIG. 16C shows a production step
illustrating a state in which a light-reflective layer is formed on
the substrate;
[0044] FIG. 17A shows a production step illustrating a state in
which an edge portion of the substrate has been washed, and FIG.
17B shows a production step illustrating a state in which a
protective layer is formed on the substrate;
[0045] FIG. 18 shows a table illustrating results of an exemplary
experiment to investigate the drying time and the film thickness
distribution ratio obtained when the shape of the lid is
changed;
[0046] FIG. 19 shows an arrangement of an exemplary production
system according to a second embodiment;
[0047] FIG. 20 shows an arrangement of an exemplary production
system according to a third embodiment;
[0048] FIG. 21 shows an arrangement of an exemplary production
system according to a fourth embodiment;
[0049] FIG. 22 shows an arrangement of an exemplary production
system according to a fifth embodiment;
[0050] FIG. 23 shows an arrangement of an exemplary production
system according to a sixth embodiment;
[0051] FIG. 24 shows an arrangement of an exemplary production
system according to a seventh embodiment; and
[0052] FIG. 25 shows an arrangement of an exemplary production
system according to an eighth embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0053] As shown in FIG. 1, a production system 10A according to a
first embodiment of the present invention comprises two molding
equipments (first and second molding equipments) 12A, 12B for
producing substrates by means of, for example, injection molding,
compression molding, or injection compression molding, an
application equipment 14 for forming a dye recording layer on the
substrate by applying a dye solution onto a first principal surface
of the substrate followed by drying, and an aftertreatment
equipment 16 for forming a light-reflective layer on the dye
recording layer of the substrate by means of, for example,
sputtering, and then applying a UV-curable solution onto the
light-reflective layer, followed by UV irradiation to form a
protective layer on the light-reflective layer.
[0054] Each of the first and second molding equipments 12A, 12B
includes a molding machine 20 for performing injection molding,
compression molding, or injection compression molding of a resin
material such as polycarbonate to produce the substrate formed, on
the first principal surface, with a tracking groove or irregularity
(groove) to indicate information such as an address signal, a
cooling section 22 for cooling the substrate taken out of the
molding machine 20, and a stacking section 26 (stack pole rotary
table) installed with a plurality of stack poles 24 for stacking
and storing the substrates after being cooled.
[0055] The application equipment 14 comprises three process units
30, 32, 34. The first process unit 30 includes a stack
pole-accommodating section 40 for accommodating the stack pole 24
transported from the first and second molding equipments 12A, 12B,
a first transport mechanism 42 for extracting the substrate one by
one from the stack pole 24 accommodated in the stack
pole-accommodating section 40 to transport the substrate to the
next step, and an electrostatic blow mechanism 44 for removing
static electricity from one substrate transported by the first
transport mechanism 42.
[0056] The second process unit 32 includes a second transport
mechanism 46 for successively transporting, to the next step, the
substrate completed for the electrostatic blow treatment in the
first process unit 30, a dye application mechanism 48 for applying
a dye solution to a plurality of substrates transported by the
second transport mechanism 46 respectively, a substrate-drying
mechanism 500 for drying the substrate completed for the dye
application treatment, and a third transport mechanism 50 for
transporting the substrate completed for the drying treatment one
by one to the next step. The dye application mechanism 48 comprises
six spin coat apparatuses 52. The substrate-drying mechanism 500
comprises six application solution-drying apparatuses 502. Each of
the application solution-drying apparatuses 502 is arranged to form
a pair with each of the spin coat apparatuses 52.
[0057] The third process unit 34 comprises a back surface-washing
mechanism 54 for washing the back surface of one substrate
transported by the third transport mechanism 50, a fourth transport
mechanism 56 for transporting, to the next step, the substrate
completed for the back surface washing, a numbering mechanism 58
for stamping a lot number or the like on the substrate transported
by the fourth transport mechanism 56, a fifth transport mechanism
60 for transporting, to the next step, the substrate completed for
the stamping of the lot number or the like, an inspecting mechanism
62 for inspecting the presence or absence of any defect and the
film thickness of the dye recording layer of the substrate
transported by the fifth transport mechanism 60, and a sorting
mechanism 68 for sorting the substrates into those to be stacked on
a stack pole 64 for normal products and those to be stacked on a
stack pole 66 for NG depending on a result of inspection performed
by the inspecting mechanism 62.
[0058] A first partition plate 70 is installed between the first
process unit 30 and the second process unit 32. A second partition
plate 72 is installed as well between the second process unit 32
and the third process unit 34 in the same manner as described
above. An opening (not shown), which has a size of such a degree
that the transport passage for the substrate transported by the
second transport mechanism 46 is not closed, is formed at a lower
portion of the first partition plate 70. An opening (not shown),
which has a size of such a degree that the transport passage for
the substrate transported by the third transport mechanism 50 is
not closed, is formed at a lower portion of the second partition
plate 72.
[0059] The aftertreatment equipment 16 includes a stack
pole-accommodating section 80 for accommodating the stack pole 64
for normal products transported from the application equipment 14,
a sixth transport mechanism 82 for extracting the substrate one by
one from the stack pole 64 accommodated in the stack
pole-accommodating section 80 and transporting the substrate to the
next step, a first electrostatic blow mechanism 84 for removing
static electricity from one substrate transported by the sixth
transport mechanism 82, a seventh transport mechanism 86 for
successively transporting the substrate completed for the
electrostatic blow treatment to the next step, a sputtering
mechanism 88 for forming, by means of sputtering, a
light-reflective layer on the first principal surface of the
substrate transported by the seventh transport mechanism 86, an
eighth transport mechanism 90 for successively transporting the
substrate completed for the sputtering of the light-reflective
layer to the next step, and an edge-washing mechanism 92 for
washing the circumferential edge (edge portion) of the substrate
transported by the eighth transport mechanism 90.
[0060] The aftertreatment equipment 16 further includes a second
electrostatic blow mechanism 94 for removing static electricity
from the substrate completed for the edge washing treatment, a
UV-curable solution-applying mechanism 96 for applying a UV-curable
solution to the first principal surface of the substrate completed
for the electrostatic blow treatment, a spin mechanism 98 for
rotating, at a high speed, the substrate completed for the
application of the UV-curable solution to obtain a uniform
application thickness of the UV-curable solution on the substrate,
a UV-radiating mechanism 100 for radiating ultraviolet light onto
the substrate completed for the application of the UV-curable
solution and the spin treatment so that the UV-curable solution is
cured to form a protective layer on the first principal surface of
the substrate, a ninth transport mechanism 102 for transporting the
substrate to the second electrostatic blow mechanism 94, the
UV-curable solution-applying mechanism 96, the spin mechanism 98,
and the UV-radiating mechanism 100 respectively, a tenth transport
mechanism 104 for transporting the substrate irradiated with UV to
the next step, a defect-inspecting mechanism 106 for inspecting the
defect of the applied surface and the protective layer surface of
the substrate transported by the tenth transport mechanism 104, a
characteristic-inspecting mechanism 108 for inspecting the signal
characteristic based on the groove formed on the substrate, and a
sorting mechanism 114 for sorting the substrates into those to be
stacked on a stack pole 110 for normal products and those to be
stacked on a stack pole 112 for NG depending on a result of
inspection performed by the defect-inspecting mechanism 106 and the
characteristic-inspecting mechanism 108.
[0061] The arrangement of one of the spin coat apparatuses 52 and
one of the application solution-drying apparatuses 502 will now be
explained with reference to FIGS. 2 to 6B.
[0062] As shown in FIGS. 2 and 3, the spin coat apparatus 52
comprises an application solution-feeding apparatus 400, a spinner
head apparatus 402, and a scattering-preventive wall 404. The
application solution-feeding apparatus 400 comprises a pressurizing
tank (not shown) filled with the dye solution, a pipe (not shown)
arranged to extend from the pressurizing tank to a nozzle 406, a
discharge amount-adjusting valve 408 for adjusting the amount of
the dye solution discharged from the nozzle 406. A predetermined
amount of the dye solution is dripped onto the surface of the
substrate 202 through the nozzle 406.
[0063] The application solution-feeding apparatus 400 is arranged
to be capable of making swinging movement from a waiting position
to a position over the substrate 202 by the aid of a handling
mechanism 414 comprising a support plate 410 for supporting the
nozzle 406 directed downwardly and a motor 412 for swinging the
support plate 410 in the horizontal direction.
[0064] The spinner head apparatus 402 is arranged under the
application solution-feeding apparatus 400. The substrate 202 is
held horizontally by the aid of a detachable fixture 420, and it is
possible to make rotation around the axis by the aid of a driving
motor (not shown).
[0065] The dye solution is dripped from the nozzle 406 of the
application solution-feeding apparatus 400 onto the substrate 202
which is rotated in a state of being horizontally held by the
spinner head apparatus 402. The dye solution is subjected to
casting toward the outer circumferential side on the surface of the
substrate 202. An excessive amount of the dye solution is separated
off from the outer circumferential edge of the substrate 202, and
it is discharged toward the outside.
[0066] The scattering-preventive wall 404 is provided around the
spinner head apparatus 402 in order that the excessive amount of
the dye solution discharged toward the outside from the outer
circumferential edge of the substrate 202 is prevented from
scattering to the surroundings. An opening 422 is formed at an
upper portion of the scattering-preventive wall 404. The excessive
amount of the dye solution, which is gathered by the aid of the
scattering-preventive wall 404, is recovered through a drain
424.
[0067] After the dye solution from the nozzle 406 is applied onto
the substrate 202, the drying treatment is started for the dye
solution.
[0068] As shown in FIG. 4, the application solution-drying
apparatus 502 functions such that a disk-shaped lid 504, which is
provided with an opening 512 at a central portion, is arranged on
the opening 422 which is provided at the upper portion of the
scattering-preventive wall 404. When the disk-shaped lid 504 is
arranged, the clean air is introduced through the opening 512
having an opening area which is smaller than that of the opening
422.
[0069] Specifically, as shown in FIGS. 4 and 5, the application
solution-drying apparatus 502 comprises four suction pads 506a to
506d for holding, by means of vacuum attraction, the disk-shaped
lid 504 to be arranged on the opening 422, a support member 526 to
which the suction pads 506a to 506d are attached, an arm 508 having
its forward end to which the support member 526 is attached, and a
driving motor 510 for swinging the arm 508 in the horizontal
direction.
[0070] The lid 504, which is held by the suction pads 506a to 506d
, is operated as follows. That is, when the driving motor 510 is
driven, then the arm 508 makes swinging movement, and it is moved
from a waiting position to a position over the opening 422. Thus,
the lid 504 is arranged on the opening 422.
[0071] As shown in FIGS. 6A and 6B, the lid 504 is a disk made of
stainless steel having the circular opening 512 at the central
portion. When the lid 504 is arranged on the opening 422, the clean
air, which is fed from an unillustrated air-conditioning system
through a HEPA filter, is introduced into the spinner head
apparatus 402 through the circular opening 512.
[0072] The circular opening 512 has its opening area which is
smaller than that of the opening 422. Accordingly, the clean air
can be allowed to flow substantially uniformly toward the entire
surface of the recording layer formed on the substrate 202.
Therefore, the recording layer can be dried to give a uniform film
thickness. Thus, it is possible to produce the
information-recording medium having good recording
characteristics.
[0073] In the case of the conventional technique, it has been
necessary to increase the environmental temperature for drying the
recording layer or the temperature of the substrate itself, rotate
the substrate at a higher speed by increasing the concentration of
the dye solution, or increase the air blow speed during the drying.
However, in the first embodiment, the foregoing necessity
disappears, and it is possible to shorten the drying time for the
recording layer. As a result, it is possible to remarkably suppress
the increase in running cost, and it is possible to improve the
throughput of the information-recording medium.
[0074] Explanation will now be made for several modified
embodiments of the lid 504 to be used in the first embodiment with
reference to FIGS. 7A to 12B.
[0075] As shown in FIGS. 7A and 7B, a lid 504 according to a first
modified embodiment has a wedge-shaped opening 514.
[0076] As shown in FIGS. 8A and 8B, a lid 504 according to a second
modified embodiment has a substantially rhombic opening 516.
[0077] As shown in FIGS. 9A and 9B, a lid 504 according to a third
modified embodiment has a first opening 518 which has a large
diameter at a central portion, and it has a plurality of second
openings which have diameters gradually decreased for those
disposed in a direction toward an outer circumference in which a
central angle resides in a spacing distance of 90.degree..
[0078] As shown in FIGS. 10A and 10B, a lid 504 according to a
fourth modified embodiment has a first opening 520 which has a
large diameter at a central portion, and it has a plurality of
second openings which have diameters gradually decreased for those
disposed in a direction toward an outer circumference in which a
central angle is 360.degree..
[0079] As shown in FIGS. 11A and 11B, a lid 504 according to a
fifth modified embodiment is formed to have a substantially conical
configuration which has a diameter continuously decreased
downwardly, and it has an opening 522 at a central portion.
[0080] As shown in FIGS. 12A and 12B, a lid 504 according to a
sixth modified embodiment has a circular opening 524 at a central
portion, and it has a plurality of fins which are formed at a lower
surface in which a central angle resides in a spacing distance of
90.degree..
[0081] Also in the first to sixth modified embodiments described
above, the film thickness of the recording layer can be made
uniform, and it is possible to produce the information-recording
medium having good recording characteristics.
[0082] The local ventilation is effected as follows for each of the
spin coat apparatuses 52 of the second process unit 32 (see FIG.
1). That is, the clean air, which is introduced through the
circular opening 512 provided through the lid 504 arranged on the
opening 422 formed at the upper portion of the
scattering-preventive wall 404, is allowed to flow against the
surface of the substrate 202.
[0083] Subsequently, the air is exhausted through an exhaust tube
426 which is attached to a lower portion of each of the spinner
head apparatuses 402.
[0084] As shown in FIGS. 13 and 14, the nozzle 406 of the
application solution-feeding apparatus 400 includes a slender
cylindrical main nozzle body 432 having a through-hole 430 formed
therethrough in the axial direction, and an attachment section 434
for fixing the main nozzle body 432 to the support plate 410 (see
FIG. 3). The main nozzle body 432 has the following surface. That
is, the forward end surface 440 and the outer or inner wall surface
or both of the outer and inner wall surfaces 442, 444 ranging over
a distance of not less than 1 mm from the forward end surface 440
are composed of a fluorine compound. Those usable as the fluorine
compound include, for example, polytetrafluoroethylene and
polytetrafluoroethylene-containing substances.
[0085] Preferred examples of the nozzle 406 to be used in this
embodiment include, for example, the nozzle 406 in which the
portion, which includes the forward end surface of the main nozzle
body 432 and which ranges over a distance of not less than 1 mm
from the forward end surface, is formed by using the fluorine
compound as shown in FIG. 14, and a nozzle 406 in which the
portion, which includes the forward end surface 440 of the main
nozzle body 432 and which includes the outer or inner wall surface
or both of the outer and inner wall surfaces 442, 444 ranging over
a distance of not less than 1 mm from the forward end surface 440,
is coated with the fluorine compound as shown in FIG. 15.
[0086] When the portion, which includes the forward end surface 440
of the main nozzle body 432 and which ranges over the distance of
not less than 1 mm from the forward end surface 440, is formed of
the fluorine compound, the following arrangement is preferable from
a practical viewpoint considering, for example, the strength. That
is, for example, the main nozzle body 432 is formed of stainless
steel. Further, the forward end surface 440 and the portion ranging
over a distance of 5 mm at the maximum from the forward end surface
440 are formed of the fluorine compound.
[0087] When the portion, which includes the forward end surface 440
of the main nozzle body 432 and which includes the outer or inner
wall surface or both of the outer and inner wall surfaces 442, 444
ranging over the distance of not less than 1 mm from the forward
end surface 440, is coated with the fluorine compound as shown in
FIG. 15, it is preferable that an area ranging over a distance of
not less than 10 mm from the forward end surface 440 of the main
nozzle body 432 is coated with the fluorine compound. It is more
preferable that the entire area of the main nozzle body 432 is
coated with the fluorine compound. When the area as described above
is coated, the thickness is not specifically limited. However, the
thickness is appropriately within a range of 5 to 500 .mu.m. The
material for the main nozzle body 432 is preferably stainless steel
as described above. The diameter of the through-hole 430 formed
through the main nozzle body 432 is generally within a range of 0.5
to 1.0 mm.
[0088] Next, the process for producing the optical disk by using
the production system 10A will be explained with reference to FIGS.
16A to 17B for illustrating the steps as well.
[0089] At first, the resin material such as polycarbonate is
subjected to injection molding, compression molding, or injection
compression molding by using the molding machine 20 of each of the
first and second molding equipments 12A, 12B to produce the
substrate 202 including the tracking groove or the irregularity
(groove) 200 for indicating information such as an address signal,
formed on the first principal surface as shown in FIG. 16A.
[0090] The material for the substrate 202 includes, for example,
polycarbonate, acrylic resin such as polymethyl methacrylate, vinyl
chloride-based resin such as polyvinyl chloride and vinyl chloride
copolymer, epoxy resin, amorphous polyolefine, and polyester. These
materials may be used in combination, if desired. Among the
materials described above, it is preferable to use polycarbonate in
view of, for example, the moisture resistance, the dimensional
stability, and the price. The depth of the groove 200 is preferably
within a range of 0.01 to 0.3 .mu.m. The half value width is
preferably within a range of 0.2 to 0.9 .mu.m.
[0091] The substrate 202, which is taken out of the molding machine
20, is cooled in the cooling section 22 disposed at the downstream
stage, and then it is stacked on the stack pole 24 with its first
principal surface directed downwardly. At the stage at which a
predetermined number of substrates 202 are stacked on the stack
pole 24, the stack pole 24 is taken out of the molding equipment
12A, 12B. The stack pole 24 is transported to the subsequent
application equipment 14, and it is accommodated in the stack
pole-accommodating section 40 of the application equipment 14. The
transport may be carried out by using a cart, or it may be carried
out by using a self-propelled automatic transport apparatus.
[0092] At the stage at which the stack pole 24 is accommodated in
the stack pole-accommodating section 40, the first transport
mechanism 42 is operated. The substrate 202 is taken out of the
stack pole 24 one by one, and it is transported to the
electrostatic blow mechanism 44 disposed at the downstream stage.
The static electricity is removed by the electrostatic blow
mechanism 44 from the substrate 202 transported to the
electrostatic blow mechanism 44. After that, the substrate 202 is
transported by the second transport mechanism 46 to the subsequent
dye application mechanism 48. The substrate 202 is introduced into
any one of the spin coat apparatuses 52 of the six spin coat
apparatuses 52. The dye solution is applied onto the first
principal surface of the substrate 202 introduced into the spin
coat apparatus 52. Subsequently, the substrate 202 is rotated at a
high speed.
[0093] At this time, the application solution-drying apparatus 502,
which is arranged to form the pair with the spin coat apparatus 52,
is operated to arrange the lid 504 on the opening 422 formed at the
upper portion of the scattering-preventive wall 404 for
constructing the spinner head apparatus 402. After that, the
substrate 202 is rotated at the high speed.
[0094] In this case, the clean air can be allowed to flow
substantially uniformly toward the dye solution on the substrate
from the circular opening 512 provided through the lid 504.
Therefore, the drying treatment is applied so that the thickness of
the dye solution is uniform. Accordingly, as shown in FIG. 16B, the
dye recording layer 204 is formed on the first principal surface of
the substrate 202.
[0095] That is, the substrate 202, which is introduced into the
spin coat apparatus 52, is installed to the spinner head apparatus
402 shown in FIG. 2, and it is held horizontally by the aid of the
fixture 420. Subsequently, the dye solution is supplied from the
pressurizing tank, and a predetermined amount of the dye solution
is adjusted by the aid of the discharge amount-adjusting valve 408.
The dye solution is dripped via the nozzle 406 onto the inner
circumferential side of the substrate 202.
[0096] As described above, the nozzle 406 has the following
surface. That is, the portion, which includes the forward end
surface 440 of the main nozzle body 432 and the outer or inner wall
surface or both of the outer and inner wall surfaces 442, 444
ranging over the distance of not less than 1 mm from the forward
end surface 440, is composed of the fluorine compound. Therefore,
the adhesion of the dye solution scarcely occurs, and the
deposition and the deposit of the dye are scarcely formed, which
would be otherwise caused when the dye solution is dried.
Therefore, the applied film can be smoothly formed without causing
any trouble such as any defect.
[0097] A dye solution, which is obtained by dissolving the dye in
an appropriate solvent, is used as the dye solution. The
concentration of the dye in the dye solution is generally within a
range of 0.01 to 15% by weight, preferably within a range of 0.1 to
10% by weight, especially preferably within a range of 0.5 to 5% by
weight, and most preferably within a range of 0.5 to 3% by
weight.
[0098] Simultaneously with the completion of the dripping of the
dye solution, the substrate 202, which is held by the spinner head
apparatus 402, is rotated at the high speed by the aid of the
driving motor. Accordingly, the dye solution, which is dripped onto
the substrate 202, is subjected to casting in the direction toward
the outer circumference on the surface of the substrate 202, and it
arrives at the outer circumferential edge of the substrate 202
while forming the applied film. The excessive dye solution, which
arrives at the outer circumferential edge, is spun out by the
centrifugal force, and it is scattered toward the surroundings of
the edge of the substrate 202. The scattered excessive dye solution
collides with the scattering-preventive wall 404, and it is
gathered in the saucer provided thereunder. After that, the
excessive dye solution is recovered through the drain 424.
[0099] Simultaneously with the start of the rotation of the
substrate 202 at the high speed, the handling mechanism 414, which
constitutes the application solution-feeding apparatus 400, is
operated to swing the nozzle 406 from the position over the
substrate 202 to the waiting position.
[0100] Simultaneously with the swinging movement of the nozzle 406
to the waiting position effected by the handling mechanism 414, the
driving motor 510, which constitutes the application
solution-drying apparatus 502, starts the driving. Accordingly, the
arm 508 is subjected to the swinging movement up to the position
over the opening 422. The lid 504, which is held by the suction
pads 506a to 506d at the forward end of the arm 508, is arranged on
the opening 422.
[0101] The clean air, which is fed through the HEPA filter from the
unillustrated air-conditioning system, is introduced into the
spinner head apparatus 402 through the circular opening 512
provided at the central portion of the lid 504 during the period
from the application process to the drying process. In this
procedure, it is preferable that the flow rate of the clean air to
be fed is set to be about 0.1 m/s, and the flow rate of the air to
be discharged through the discharge tube 426 is set to be about 0.5
m/s to 1.0 m/s.
[0102] When the opening 422 is compared with the circular opening
512, the opening area of the circular opening 512 is smaller than
that of the opening 422. Accordingly, when the clean air is
introduced through the circular opening 512, the clean air can be
allowed to flow substantially uniformly toward the entire surface
of the recording layer formed on the substrate 202. Therefore, the
recording layer can be dried while making the film thickness to be
uniform. Thus, it is possible to produce the information-recording
medium having good recording characteristics.
[0103] Further, the drying time for the recording layer can be
shortened without increasing the environmental temperature for
drying the recording layer or the temperature of the substrate
itself, without rotating the substrate at a higher speed by
increasing the concentration of the dye solution, or without
increasing the air blow speed during the drying. Therefore, it is
possible to remarkably suppress the increase in running cost.
Further, it is possible to improve the throughput of the
information-recording medium.
[0104] In general, the thickness of the applied film (dye recording
layer 204) is within a range of 20 to 500 nm, and preferably within
a range to 50 to 300 nm.
[0105] In the present invention, the dye to be used for the dye
recording layer 204 is not specifically limited. Those usable as
the dye include, for example, cyanine dye, phthalocyanine dye,
imidazoquinoxaline dye, pyrylium dye, thiopyrylium dye, azulenium
dye, squalirium dye, metal complex dye based on, for example, Ni or
Cr, naphthoquinone dye, anthraquinone dye, indophenol dye,
indoaniline dye, triphenylmethane dye, merocyanine dye, oxonol dye,
aminium dye, diimmonium dye, and nitroso compound. Among these
dyes, it is preferable to use cyanine dye, phthalocyanine dye,
azulenium dye, squalirium dye, oxonol dye, and imidazoquinoxaline
dye.
[0106] The solvent of the application agent for forming the dye
recording layer 204 includes, for example, ester such as butyl
acetate and cellosolve acetate; ketone such as methyl ethyl ketone,
cyclohexanone, and methyl isobutyl ketone; chlorinated hydrocarbon
such as dichloromethane, 1,2-dichloroethane, and chloroform; amide
such as dimethylformamide, hydrocarbon such as cyclohexane; ether
such as tetrahydrofuran, ethyl ether, and dioxane; alcohol such as
ethanol, n-propanol, isopropanol, n-butanol, and diacetone alcohol;
fluorine solvent such as 2,2,3,3,-tetrafluoro-1-propanol, and
glycol ether such as ethylene glycol monomethyl ether, ethylene
glycol monoethyl ether, and propylene glycol monomethyl ether.
[0107] The solvent may be used singly or in combination of two or
more species in an appropriate manner considering the dissolving
property of the dye to be used. Preferably, the fluorine solvent
such as 2,2,3,3,-tetrafluoro-1-propanol is used. An anti-fading
agent and a binder may be added to the dye solution, if desired.
Further, a variety of additives such as an antioxidant, a
UV-absorbing agent, a plasticizer, and a lubricant may be added to
the dye solution depending on the purpose of the use.
[0108] Representative examples of the anti-fading agent include
nitroso compound, metal complex, diimmonium salt, and aminium salt.
These examples are described, for example, in respective patent
documents such as Japanese Laid-Open Patent Publication Nos.
2-300288, 3-224793, and 4-146189.
[0109] The binder includes, for example, natural organic
high-molecular compound such as gelatin, cellulose derivative,
dextran, rosin, and rubber; and synthetic organic high-molecular
compound including, for example, hydrocarbon resin such as
polyethylene, polypropylene, polystyrene, and polyisobutylene,
vinyl resin such as polyvinyl chloride, polyvinyl vinylidene, and
polyvinyl chloride-polyvinyl acetate copolymer, acrylic resin such
as polymethyl acrylate and polymethyl methacrylate, polyvinyl
alcohol, chlorinated polyethylene, epoxy resin, butylal resin,
rubber derivative, and initial condensate of thermosetting resin
such as phenol-formaldehyde resin.
[0110] When the binder is used, the binder is generally used in an
amount of not more than 20 parts by weight, preferably not more
than 10 parts by weight, and more preferably not more than 5 parts
by weight with respect to 100 parts by weight of the dye.
[0111] An undercoat layer may be provided on the surface of the
substrate 202 on the side on which the dye recording layer 204 is
formed, for example, in order to improve the flatness, improve the
adhesive force, and avoid the deterioration of quality of the dye
recording layer 204.
[0112] The material for the undercoat layer includes, for example,
high-molecular compound such as polymethyl methacrylate, acrylic
acid-methacrylic acid copolymer, styrene-maleic anhydride
copolymer, polyvinyl alcohol, N-methylol acrylamide,
styrene-vinyltoluene copolymer, chlorosulfonated polyethylene,
nitrocellulose, polyvinyl chloride, chlorinated polyolefine,
polyester, polyimide, vinyl acetate-vinyl chloride copolymer,
ethylene-vinyl acetate copolymer, polyethylene, polypropylene, and
polycarbonate; and surface modifier such as silane coupling
agent.
[0113] The undercoat layer can be formed such that the foregoing
substance is dissolved or dispersed in an appropriate solvent to
prepare a dye solution, and then the dye solution is applied to the
surface of the substrate 202 by utilizing an application method
such as spin coat, dip coat, and extrusion coat. The layer
thickness of the undercoat layer is generally within a range of
0.005 to 20 Am, and preferably within a range of 0.01 to 10
.mu.m.
[0114] The substrate 202, on which the dye recording layer 204 is
formed, is transported by the third transport mechanism 50 to the
subsequent back surface-washing mechanism 54 to wash the surface
(back surface) on the side opposite to the first principal surface
of the substrate 202. After that, the substrate 202 is transported
by the fourth transport mechanism 56 to the subsequent numbering
mechanism 58. The stamping such as a lot number is made on the
first principal surface or the back surface of the substrate
202.
[0115] After that, the substrate 202 is transported by the fifth
transport mechanism 60 to the subsequent inspecting mechanism 62 to
inspect the presence or absence of any defect of the substrate 202
and the film thickness of the dye recording layer 204. The
inspection is performed by radiating light onto the back surface of
the substrate 202, and effecting image processing for the
transmitted state of light by using, for example, a CCD camera. The
result of inspection obtained by the inspecting mechanism 62 is
sent to the subsequent sorting mechanism 68.
[0116] The substrate 202, which has been completed for the
inspection process described above, is sorted and transported by
the sorting mechanism 68 to the stack pole 64 for normal products
or the stack pole 66 for NG on the basis of the inspection
result.
[0117] At the stage at which a predetermined number of substrates
202 are stacked on the stack pole 64 for normal products, the stack
pole 64 for normal products is taken out of the application
equipment 14, and it is transported to the subsequent
aftertreatment equipment 16. The stack pole 64 is accommodated in
the stack pole-accommodating section 80 of the aftertreatment
equipment 16. The transport may be carried out by using a cart, or
it may be carried out by using a self-propelled automatic transport
apparatus.
[0118] At the stage at which the stack pole 64 for normal products
is accommodated in the stack pole-accommodating section 80, the
sixth transport mechanism 82 is operated. The substrate 202 is
taken out of the stack pole 64 one by one, and it is transported to
the first electrostatic blow mechanism 84 disposed at the
downstream stage. The static electricity is removed by the first
electrostatic blow mechanism 84 from the substrate 202 transported
to the first electrostatic blow mechanism 84. After that, the
substrate 202 is transported by the seventh transport mechanism 86
to the subsequent sputtering mechanism 88.
[0119] As shown in FIG. 16C, the light-reflective layer 208 is
formed by sputtering on the entire surface except for the
circumferential edge portion 206 of the first principal surface of
the substrate 202 introduced into the sputtering mechanism 88.
[0120] The light-reflective substance, which is the material for
the light-reflective layer 208, is a substance having a high
reflectance with respect to the laser beam. The light-reflective
substance includes, for example, stainless steel, metalloid, and
metal such as Mg, Se, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re,
Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Si,
Ge, Te, Pb, Po, Sn, and Bi.
[0121] Among them, it is preferable to use Cr, Ni, Pt, Cu, Ag, Au,
Al, and stainless steel. The substances may be used singly or in
combination of two or more species. Alternatively, the substances
may be used as an alloy. It is especially preferable to use Ag or
an alloy thereof.
[0122] The light-reflective layer 208 can be formed on the
recording layer 204, for example, by performing vapor deposition,
sputtering, or ion plating for the light-reflective substance
described above. The layer thickness of the reflective layer is
generally within a range of 10 to 800 nm, preferably within a range
of 20 to 500 nm, and more preferably within a range of 50 to 300
nm.
[0123] The substrate 202, on which the light-reflective layer 208
is formed, is transported by the eighth transport mechanism 90 to
the subsequent edge-washing mechanism 92. As shown in FIG. 17A, the
edge portion 206 on the first principal surface of the substrate
202 is washed to remove the dye recording layer 204 having been
formed on the edge portion 206. After that, the substrate 202 is
transported by the ninth transport mechanism 102 to the subsequent
second electrostatic blow mechanism 94 to remove the static
electricity.
[0124] After that, the substrate 202 is transported by the ninth
transport mechanism 102 as well to the UV-curable solution-applying
mechanism 96. The UV-curable solution is dripped onto a part of the
first principal surface of the substrate 202. After that, the
substrate 202 is transported by the ninth transport mechanism 102
as well to the subsequent spin mechanism 98. The substrate 202 is
rotated at a high speed. Thus, the application thickness of the
UV-curable solution dripped onto the substrate 202 is made uniform
over the entire surface of the substrate 202.
[0125] In the first embodiment, the time schedule is managed such
that the period of time is not less than 2 seconds and within 5
minutes after the film of the light-reflective layer 208 is formed
until the UV-curable solution is applied.
[0126] After that, the substrate 202 is transported by the ninth
transport mechanism 102 as well to the subsequent UV-radiating
mechanism 100. The ultraviolet light is radiated onto the
UV-curable solution on the substrate 202. Accordingly, as shown in
FIG. 17B, the protective layer 210 composed of the UV-curable resin
is formed so that the light-reflective layer 208 and the dye
recording layer 204 formed on the first principal surface of the
substrate 202 are covered therewith. Thus, the optical disk D is
constructed.
[0127] The protective layer 210 is provided on the light-reflective
layer 208 in order that the dye recording layer 204 or the like is
protected physically and chemically. The protective layer 210 may
be also provided on the side of the substrate 202 on which the dye
recording layer 204 is not provided, in order to enhance the
scratch resistance and the moisture resistance. The material usable
for the protective layer 210 includes, for example, inorganic
substance such as SiO, SiO.sub.2, MgF.sub.2, SnO.sub.2, and
Si.sub.3N.sub.4; and organic substance such as thermoplastic resin,
thermosetting resin, and UV-curable resin.
[0128] The protective layer 210 can be formed, for example, by
laminating a film obtained by extrusion of plastic, onto the
light-reflective layer 208 and/or the substrate 202 by the aid of
an adhesive. Alternatively, the protective layer 210 may be
provided by means of another method such as vacuum deposition,
sputtering, and application. When a thermoplastic resin or a
thermosetting resin is used, the protective layer 210 can be also
formed by dissolving the resin in an appropriate solvent to prepare
an application solution, and then applying the application
solution, followed by being dried.
[0129] In the case of the UV-curable resin, the protective layer
210 can be formed as described above by using the resin as it is or
dissolving the resin in an appropriate solvent to prepare an
application solution, and then applying the application solution,
followed by being irradiated with UV light to cure the resin. A
variety of additives such as an antistatic agent, an antioxidant,
and a UV-absorbing agent may be further added to the application
solution depending on the purpose of the use. The layer thickness
of the protective layer 210 is generally within a range of 0.1 to
100 .mu.m.
[0130] After that, the optical disk D is transported by the tenth
transport mechanism 104 to the subsequent defect-inspecting
mechanism 106 and the characteristic-inspecting mechanism 108 to
inspect the presence or absence of the defect on the surface of the
dye recording layer 204 and the surface of the protective layer 210
and the signal characteristic based on the groove 200 formed on the
substrate 202 of the optical disk D. These inspections are
performed by radiating light onto the both surfaces of the optical
disk D respectively, and effecting image processing for the
reflected light by using, for example, a CCD camera. The results of
inspection obtained by the defect-inspecting mechanism 106 and the
characteristic-inspecting mechanism 108 are sent to the subsequent
sorting mechanism 114.
[0131] The optical disk D, which has been completed for the defect
inspection process and the characteristic inspection process
described above, is sorted and transported by the sorting mechanism
114 to the stack pole 110 for normal products or the stack pole 112
for NG on the basis of the respective inspection results.
[0132] At the stage at which a predetermined number of optical
disks D are stacked on the stack pole 110 for normal products, the
stack pole 110 is taken out of the aftertreatment equipment 16, and
it is introduced into an unillustrated label-printing step.
[0133] As described above, in the production system 10A according
to the first embodiment, when the dye recording layer 204 formed on
the substrate 202 is dried, then the substrate 202 applied with the
dye is rotated at the high speed, and the intake for introducing
the clean air is narrowed. Accordingly, the clean air can be
allowed to flow substantially uniformly toward the entire surface
of the dye recording layer 204 formed on the substrate 202.
Therefore, the film thickness of the recording layer can be made
uniform, and it is possible to produce the information-recording
medium having good recording characteristics.
[0134] Further, the drying time for the dye recording layer 204 can
be shortened without increasing the environmental temperature for
drying the dye recording layer 204 or the temperature of the
substrate 202 itself, without rotating the substrate at a higher
speed by increasing the concentration of the dye solution, or
without increasing the air blow speed during the drying. Therefore,
it is possible to remarkably suppress the increase in running cost.
Further, it is possible to improve the throughput of the
information-recording medium.
[0135] An illustrative experiment will now be explained. In this
illustrative experiment, respective samples were prepared for
Working Examples 1 and 2 and Comparative Examples 1 and 2. The
optical disk D was produced by using the production system 10A
shown in FIG. 1 to compare a case in which the lid 504 was arranged
on the opening 422 formed at the upper portion of the
scattering-preventive wall 404 for constructing the spinner head
apparatus 402 with a case in which the lid 504 was not arranged, in
the dry process for the substrate 202 applied with the dye. On this
condition, investigation was made for respective samples concerning
the drying time and the film thickness distribution ratio for the
inner and outer circumferential portions.
[0136] In this experiment, Working Example 1 is illustrative of a
case in which the disk-shaped lid 504, which is provided with the
opening of 50 mm at the central portion, is arranged after the
completion of dripping of the dye solution. Working Example 2 is
illustrative of a case in which the disk-shaped lid 504, which is
provided with the wedge-shaped opening, is arranged after the
completion of dripping of the dye solution.
[0137] On the other hand, Comparative Example 1 is illustrative of
a case in which no lid is put on after the completion of dripping
of the dye solution. Comparative Example 2 is illustrative of a
case in which a disk-shaped lid having no opening is arranged after
the completion of dripping of the dye solution.
[0138] The dye recording layer 204 is formed as follows. 2.65 g of
a cyanine dye compound represented by the following general formula
(1) and 0.265 g of an anti-fading agent represented by the
following general formula (2) are combined and blended, and they
are dissolved in 100 cc of 2,2,3,3,-tetrafluoro-1-propanol
represented by the following general formula (3) to prepare a dye
solution for forming the recording layer. 1
[0139] After that, the dye solution is applied by spin coat onto
the surface of the groove side of a polycarbonate substrate
(diameter: 120 mm, thickness: 1.2 mm) having a spiral-shaped groove
200 (track pitch: 1.6 .mu.m, groove width: 0.4 .mu.m, groove depth:
0.16 .mu.m) formed by injection molding on the surface, while
changing the number of revolutions from 300 rpm to 4000 rpm to form
the dye recording layer 204 (thickness in the groove: about 200
nm).
[0140] Obtained experimental results are shown in FIG. 18. As
clearly understood from FIG. 18, in Working Examples 1 and 2, the
lid having the opening is arranged during the drying of the dye
solution. Accordingly, the drying time for the dye recording layer
204 is shortened, and it is possible to obtain the substantially
uniform film thickness for the inner and outer circumferential
surfaces.
[0141] Further, in Working Examples 1 and 2, the drying time for
the dye recording layer 204 can be shortened without increasing the
environmental temperature for drying the dye recording layer 204 or
the temperature of the substrate 202 itself, without rotating the
substrate 202 at a higher speed by increasing the concentration of
the dye solution, or without increasing the air blow speed during
the drying. Therefore, it is possible to remarkably suppress the
increase in running cost. Further, it is possible to improve the
throughput of the information-recording medium.
[0142] Next, a production system 10B according to a second
embodiment of the present invention will be explained with
reference to FIG. 19. The same constitutive components of the
production system 10B according to the second embodiment as those
of the production system 10A according to the first embodiment are
designated by the same reference numerals, detailed explanation of
which will be omitted. The following description will be made in
the same manner as described above.
[0143] As shown in FIG. 19, the production system 10B according to
the second embodiment comprises a molding machine 20 for producing
the substrate 202, a cooling section 22, and a manufacturing
section 600 for producing the optical disk D from the substrate 202
after the cooling treatment.
[0144] The substrate 202, which is produced by the molding machine
20, is transported to the cooling section 22 by the aid of a
transport mechanism 602. The substrate 202, which is cooled by the
cooling section 22, is stacked and stored on the stack pole 24
installed as a plurality of individuals for the stacking section 26
(stack pole rotary table).
[0145] The manufacturing section 600 comprises three process units
604, 606, 608. The first process unit 604 includes a dye
application mechanism 48 for forming the dye recording layer 204
(see FIG. 13) on the substrate 202 by applying the dye solution
onto the first principal surface of the substrate 202 followed by
drying, an inspecting mechanism 62 for inspecting the presence or
absence of the defect and the film thickness of the dye recording
layer 204 after applying the dye solution, and a sorting mechanism
68 for sorting the substrates 202 into those to be stacked on a
stack pole 64 for normal products and those to be stacked on a
stack pole 66 for NG depending on a result of inspection performed
by the inspecting mechanism 62.
[0146] The first process unit 604 is further provided with an arm
mechanism 610 for taking out the substrate 202 stacked on the stack
pole 24 one by one and transporting it to the dye application
mechanism 48, and transporting, to the inspecting mechanism 62, the
substrate 202 to which the dye solution is applied by the dye
application mechanism 48.
[0147] The second process unit 606 includes a substrate-drying
mechanism 500 for drying the substrate 202 in order to stabilize
the light reflectance of the dye recording layer 204 formed on the
substrate 202, an eleventh transport mechanism 612 for transporting
the substrate 202 from the stack pole 64 for normal products to the
substrate-drying mechanism 500, and a twelfth transport mechanism
614 for successively transporting, from the substrate-drying
mechanism 500 to the next step, the substrate 202 subjected to the
stabilizing treatment for the light reflectance for the dye
recording layer 204.
[0148] The third process unit 608 includes a sputtering mechanism
88 for forming, by means of sputtering, the light-reflective layer
on the dye recording layer 204 of the substrate 202 transported by
the twelfth transport mechanism 614, an edge-washing mechanism 92
for washing the circumferential edge (edge portion) of the
substrate 202 completed for the sputtering of the light-reflective
layer, a UV-curable solution-applying mechanism 96 for applying a
UV-curable solution onto the dye recording layer of the substrate
202 subjected to the edge washing, a spin mechanism 98 for
rotating, at a high speed, the substrate 202 applied with the
UV-curable solution to obtain a uniform application thickness of
the UV-curable solution on the substrate 202, a UV-radiating
mechanism 100 for radiating ultraviolet light onto the substrate
202 completed for the application of the UV-curable solution and
the spin treatment so that the UV-curable solution is cured to form
the protective layer on the light-reflective layer of the substrate
202, a defect-inspecting mechanism 106 for inspecting the defect of
the applied surface and the protective layer surface of the
UV-irradiated substrate 202, a characteristic-inspecting mechanism
108 for inspecting the signal characteristic based on the groove
formed on the substrate 202, and a sorting mechanism 114 for
sorting the substrates 202 into those to be stacked on a stack pole
110 for normal products and those to be stacked on a stack pole 112
for NG depending on a result of inspection performed by the
defect-inspecting mechanism 106 and the characteristic-inspecting
mechanism 108.
[0149] The third process unit 608 is further provided with a rotary
type transport mechanism 616 for successively transporting the
substrate 202 one by one to the respective mechanisms, i.e., the
sputtering mechanism 88, the edge-washing mechanism 92, the
UV-curable solution-applying mechanism 96, the spin mechanism 98,
the UV-radiating mechanism 100, the defect-inspecting mechanism
106, and the characteristic-inspecting mechanism 108.
[0150] The rotary type transport mechanism 616 has a disk-shaped
rotary section at a central portion. The rotary section is provided
with eight arms which are disposed at equal intervals. Suction pads
for holding the substrate 202 are provided at forward end portions
of the eight arms. When the rotary section is rotated, the
substrate 202, which is held by the suction pad provided for each
of the eight arms, is successively transported to the respective
mechanisms 88, 92, 96, 98, 100, 106 which constitute the third
process unit 608.
[0151] Next, explanation will be made for the process for producing
the optical disk by using the production system 10B according to
the second embodiment.
[0152] At first, the resin material such as polycarbonate is
subjected to injection molding, compression molding, or injection
compression molding by using the molding machine 20 to produce the
substrate 202 including the tracking groove or the irregularity
(groove) 200 for indicating information such as an address signal,
formed on the first principal surface as shown in FIG. 16A.
[0153] The substrate 202, which is taken out of the molding machine
20, is transported by the transport mechanism 602 to the cooling
section 22, and it is cooled in the cooling section 22. After that,
the substrate 22 is stacked on the stack pole 24 with its first
principal surface directed downwardly. The substrate 202, which is
stacked on the stack pole 24, is transported successively one by
one to the dye application mechanism 48 by the aid of the arm
mechanism 610.
[0154] The dye solution is applied onto the first principal surface
of the substrate 202 transported to the dye application mechanism
48. Subsequently, the substrate 202 is rotated at a high speed to
obtain a uniform thickness of the applied solution, and then it is
subjected to the drying treatment. Accordingly, as shown in FIG.
16B, the dye recording layer 204 is formed on the first principal
surface of the substrate 202.
[0155] The substrate 202, on which the dye recording layer 204 is
formed, is transported to the inspecting mechanism 62 by the aid of
the arm mechanism 610 to perform the inspection for the presence or
absence of the defect of the substrate 202 and the film thickness
of the dye recording layer 204.
[0156] The substrate 202, which is completed for the inspection
treatment as described above, is sorted and transported to the
stack pole 64 for normal products or the stack pole 66 for NG by
the aid of the sorting mechanism 68 on the basis of the result of
the inspection.
[0157] When the substrate 202 is stacked on the stack pole 64 for
normal products, the eleventh transport mechanism 612 is operated
simultaneously therewith to take out the substrate 202 one by one
from the stack pole 64 and transport it to the substrate-drying
mechanism 500. The substrate 202, which is transported to the
substrate-drying mechanism 500, is dried in the substrate-drying
mechanism 500 to thereby stabilize the light reflectance of the dye
recording layer 204 formed on the substrate 202. After that, the
substrate 202 is transported to the subsequent sputtering mechanism
88 by the aid of the twelfth transport mechanism 614.
[0158] In the second embodiment, the condition of the drying
treatment for the substrate 202 performed by the substrate-drying
mechanism 500 is managed such that the temperature is 80.degree. C.
and the time is 20 minutes.
[0159] As shown in FIG. 16C, the light-reflective layer 208 is
formed by the sputtering on the entire surface except for the
circumferential edge portion 206 of the first principal surface of
the substrate 202 introduced into the sputtering mechanism 88.
[0160] The substrate 202, on which the light-reflective layer 208
is formed, is transported to the subsequent edge-washing mechanism
92 by the aid of the rotary type transport mechanism 616. As shown
in FIG. 17A, the edge portion 206 of the first principal surface of
the substrate 202 is washed to remove the dye recording layer 204
having been formed on the edge portion 206.
[0161] After that, the substrate 202 is transported to the
UV-curable solution-applying mechanism 96 by the aid of the rotary
type transport mechanism 616. The UV-curable solution is dripped to
a part of the first principal surface of the substrate 202.
Subsequently, the substrate 202 is further transported to the
subsequently spin mechanism 98 by the aid of the rotary type
transport mechanism 616. The substrate is rotated at a high speed
to thereby obtain a uniform application thickness of the UV-curable
solution dripped on the substrate 202 over the entire surface of
the substrate 202.
[0162] After that, the substrate 202 is transported to the
subsequent UV-radiating mechanism 100 by the aid of the rotary type
transport mechanism 616 as well. The UV-curable solution on the
substrate 202 is irradiated with the ultraviolet light.
Accordingly, as shown in FIG. 17B, the protective layer 210 based
on the UV-curable resin is formed to coat the dye recording layer
204 and the light-reflective layer 208 formed on the first
principal surface of the substrate 202. Thus, the optical disk D is
constructed.
[0163] After that, the optical disk D is transported to the
subsequent defect-inspecting mechanism 106 and the
characteristic-inspecting mechanism 108 by the aid of the rotary
type transport mechanism 616 to inspect the presence or absence of
the defect of the surface of the dye recording layer 204 and the
surface of the protective layer 210 and the signal characteristic
based on the groove 200 formed on the substrate 202 of the optical
disk D.
[0164] The optical disk D, which is completed for the
defect-inspecting process and the characteristic-inspecting process
as described above, is sorted and transported to the stack pole 110
for normal products or the stack pole 112 for NG by the aid of the
sorting mechanism 114 on the basis of the results of the respective
inspections.
[0165] At the stage at which a predetermined number of optical
disks D are stacked on the stack pole 110 for normal products, the
stack pole 110 is taken out of the third process unit 608, and it
is introduced into an unillustrated label-printing step.
[0166] As shown in FIG. 20, a production system 10C according to a
third embodiment of the present invention comprises two molding
machines 20A, 20B, two dye application mechanisms 48A, 48B, and one
sputtering mechanism 88.
[0167] As shown in FIG. 21, a production system 10D according to a
fourth embodiment of the present invention comprises three molding
machines 20A, 20B, 20C, four dye application mechanisms 48A, 48B,
48C, 48D, and one sputtering mechanism 88.
[0168] As shown in FIG. 22, a production system 10E according to a
fifth embodiment of the present invention comprises three molding
machines 20A, 20B, 20C, three dye application mechanisms 48A, 48B,
48C, and one sputtering mechanism 88.
[0169] As shown in FIG. 23, a production system 10F according to a
sixth embodiment of the present invention comprises four molding
machines 20A, 20B, 20C, 20D, four dye application mechanisms 48A,
48B, 48C, 48D, and two sputtering mechanism 88A, 88B.
[0170] As shown in FIG. 24, a production system 10G according to a
seventh embodiment of the present invention comprises four molding
machines 20A, 20B, 20C, 20D, six dye application mechanisms 48A,
48B, 48C, 48D, 48E, 48F, and two sputtering mechanism 88A, 88B.
[0171] As shown in FIG. 25, a production system 10H according to an
eighth embodiment of the present invention comprises two molding
machines 20A, 20B, three dye application mechanisms 48A, 48B, 48C,
and one sputtering mechanism 88.
[0172] As described above, in the production systems 10B to 10H
according to the second to eighth embodiments, the production line
is constructed so that the relationship of n/m<2 is satisfied
provided that m represents the number of molding machine or
machines 20, and n represents the number of dye application
mechanism or mechanisms 48 for forming the dye recording layer 204.
Therefore, the production line can be simplified, the quality
control can be easily performed, and the maintenance cost can be
reduced, making it possible to realize a small scale of the
production equipment and reduce the installation space so that the
low price of the information-recording medium produced thereby may
be realized and the improvement in yield may be achieved.
[0173] It is a matter of course that the information-recording
medium and the method for producing the same according to the
present invention are not limited to the embodiments described
above, which may be embodied in other various forms without
deviating from the gist or essential characteristics of the present
invention.
* * * * *