U.S. patent application number 12/075754 was filed with the patent office on 2008-07-31 for method for producing holographic recording medium.
This patent application is currently assigned to KONICA MINOLTA MEDICAL & GRAPHIC, INC.. Invention is credited to Toshihisa Takeyama.
Application Number | 20080182177 12/075754 |
Document ID | / |
Family ID | 33447737 |
Filed Date | 2008-07-31 |
United States Patent
Application |
20080182177 |
Kind Code |
A1 |
Takeyama; Toshihisa |
July 31, 2008 |
Method for producing holographic recording medium
Abstract
A method for producing a holographic recording medium having a
holographic recording layer between a first substrate and a second
substrate including the steps of: providing a holographic recording
layer forming composition onto the first substrate, forming the
holographic recording layer between the first and substrate and the
second substrate by facing the second substrate to the first
substrate, and hardening the holographic recording layer by at
least one of heat and light.
Inventors: |
Takeyama; Toshihisa; (Tokyo,
JP) |
Correspondence
Address: |
FRISHAUF, HOLTZ, GOODMAN & CHICK, PC
220 Fifth Avenue, 16TH Floor
NEW YORK
NY
10001-7708
US
|
Assignee: |
KONICA MINOLTA MEDICAL &
GRAPHIC, INC.
Tokyo
JP
|
Family ID: |
33447737 |
Appl. No.: |
12/075754 |
Filed: |
March 13, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10846896 |
May 14, 2004 |
7362523 |
|
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12075754 |
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Current U.S.
Class: |
430/2 ;
G9B/7.147; G9B/7.166; G9B/7.194; G9B/7.197 |
Current CPC
Class: |
G11B 7/245 20130101;
G11B 7/24044 20130101; G03H 2250/37 20130101; G11B 7/265 20130101;
G03H 2260/12 20130101; G03H 2270/20 20130101; G03H 1/0252 20130101;
G03H 2001/186 20130101; G03H 2260/30 20130101; G11B 7/26 20130101;
G11B 7/0033 20130101; Y10S 359/90 20130101 |
Class at
Publication: |
430/2 |
International
Class: |
G03F 7/00 20060101
G03F007/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 28, 2003 |
JP |
JP2003-150734 |
Claims
1-45. (canceled)
46. A method for producing a holographic recording medium having a
holographic recording layer between a first substrate and a second
substrate comprising the steps, conducted sequentially in the
following order, of: forming a space between the first substrate
and the second substrate and enclosing the space with an inner side
space retaining member and an outer side space retaining member to
retain a designated distance between the first and second
substrates, wherein one of the inner side space retaining member
and the outer side space retaining member has at least one opening
through which a holographic recording layer forming composition is
charged into the space on the condition of holding the first
substrate and the second substrate so that the designated distance
is retained between the substrates, reducing pressure in the space
by a pressure controlling means, charging the holographic recording
layer forming composition into the space through the at least one
opening to form the holographic recording layer; and hardening the
holographic recording layer by at least one of heat and light.
47. (canceled)
48. The method of claim 46, wherein the step of the charging
comprises the holographic recording layer forming composition into
the space while the reduced pressure in the space is
maintained.
49. The method of claim 46, further comprising the steps of:
holding the first substrate by a first substrate holding member;
holding the second substrate by a second substrate holding member;
and wherein the step of forming the space comprises the step of:
facing the second substrate held by the second substrate holding
member to the first substrate held by the first substrate holding
member.
50. The method of claim 49, wherein the first substrate and the
first substrate holding member are brought in contact with each
other by vacuum.
51. The method of claim 50, wherein the second substrate and the
second substrate holding member are brought in contact with each
other by vacuum.
52. The method of claim 49, further comprising the step of:
providing the inner side space retaining member and the outer side
space retaining member between the first substrate and the second
substrate during the step of facing the second substrate to the
first substrate.
53. The method of claim 46, further comprising the step of:
removing the holographic recording layer forming composition forced
out from the area of facing the second substrate to the first
substrate.
54. The method of claim 46, further comprising the step of: cutting
the holographic recording medium into a designated size after the
step of hardening.
55. The method of claim 46, further comprising the step of: sealing
the bare portion of the holographic recording layer.
56. The method of claim 46, wherein the holographic recording
medium satisfies the relation of 0.15.ltoreq.Dh/(D1+D2).ltoreq.2.0
wherein D1 is the thickness of the first substrate, D2 is the
thickness of the second substrate and Dh is the thickness of the
holographic recording medium.
57. The method of claim 56, wherein the thickness of the
holographic recording layer Dh is from 200 .mu.m to 2.0 mm.
58. The method of claim 56, wherein the relation of the thickness
of the first substrate D1 and the thickness of the second substrate
D2 is D1.ltoreq.D2.
59. The method of claim 46, wherein the first substrate is
transparent and subjected to an anti-reflection treatment on the
side opposite to the side on which the holographic recording layer
is provided.
60. The method of claim 46, wherein the material of the first
substrate is glass.
61. The method of claim 46, wherein a reflective layer having a
reflectance of not less than 70% is provided on the at least one of
the face of the second substrate on which the holographic recording
layer to be provided and the face opposite thereto.
62. The method of claim 46, wherein the shape of the holographic
recording medium is a disc.
63. The method of claim 46, wherein the shape of the holographic
recording medium is a card.
64. The method of claim 46, further comprising the step of:
removing a bubble included in the holographic recording layer
formed by the step of forming.
65. The method of claim 46, wherein the step of reducing pressure
includes a step of placing an empty recording medium in which a
recording layer forming composition is not charged into the space
in an enclosed room and a step of reducing pressure in the enclosed
room such that the pressure in the space is reduced.
66. The method of claim 46, wherein the step of charging comprises
the steps of: immersing the opening into the holographic recording
layer forming composition; and restoring the pressure in the
enclosed room to the original pressure by the pressure controlling
means to charge the holographic recording layer forming composition
into the space.
Description
[0001] This application is a divisional of application Ser. No.
10/846,896 filed May 14, 2004 (issue fee paid) which is
incorporated herein in its entirety by this reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a method for producing a
holographic recording medium capable of having a great recording
capacity.
BACKGROUND OF THE INVENTION
[0003] Recently, high speed and large capacity mutual data
communication is increased accompanied with the spreading of
internet and broad band communication. Moreover, the volume of data
stored by governmental organs is rapidly enlarged with the
expansion of the electronic governance promoted by Governments of
many countries. Furthermore, it is expected that the needs for a
photo-recording and reduction equipment and a recording medium
having a high memory capacity is raised according to the spreading
of high-vision and ground digital broadcasting.
[0004] Among the photo-recording-reproduction equipment having high
memory capacity, a page memory system, particularly holographic
recording-reproduction equipment, has been proposed as one instead
of usual memory equipment. Such the equipment is noted since the
system has randomly accessible high capacity memory. The
holographic recording-reproduction equipment and the recording
media to be used in such the equipment are described in some
publications, for example, Hans J. Coufal et al. "Holographic Data
Storage (Springer Series in Optical Sciences, Vol. 76)"
Springer-Verlag GmbH & Co. KG, August 2000.
[0005] As a holographic recording-reproduction system applied in
the holographic recording-reproduction equipment, a
recording-reproduction method using a holographic recording medium
in which transparent substrates are arranged on both sides of a
holographic recording layer such as that described in U.S. Pat. No.
5,719,691, and a recording-reproduction method using a holographic
recording medium have been proposed, in which a reflective surface
is arranged on one side of a holographic recording layer such as
that described in Japanese Patent Publication Open to Public
Inspection, hereinafter referred to as JP O.P.I. Publication, No.
2002-123949.
[0006] The holographic recording is based on the principal that the
information is recorded by exposing the recording layer to
holographic light for locally changing the refractive index of the
recording layer, and the information is reproduced by reading the
change of the refractive index in the recording layer. Various
holographic recording layers are proposed, for example, one using
inorganic substances such as those described in British Patent No.
9,929,953, one using substances capable of occurring structural
isomerism by light such as those described in JP O.P.I. Publication
No. 10-340479, and one utilizing the diffusion polymerization of
photopolymer such as those described in U.S. Pat. Nos. 5,759,721,
and 6,103,454. Among them, the materials using the photopolymer
described in U.S. Pat. Nos. 5,759,721 and 6,103,454 have been
actively investigated recently since such the material is high
sensitive and the difference of the refractive index can be easily
formed.
[0007] However, such the methods have a problems that the
production process such as the spattering or the spin coating
utilized for usual photo-recording media are difficulty applied for
the holographic recording medium since the thickness of the
recording layer of the holographic recording medium using the
photopolymer is thicker compared with the usual photo-recording
media such as CD-R, CD-RW, DVD-R, DVD-RW, DVD-RAM and DVD-ROM, and
is usually more than 200 .mu.m.
[0008] Moreover, in the photo-recording medium using the
photopolymer, it is effective to raise the mobility of the compound
in the recording layer for making the difference between the
refractive index of the holographically exposed area and that of
the unexposed area. However, when the mobility of the compound in
the layer is raised, the medium shows a drawback such as that
formation of the unevenness of thickness of the recording layer of
the photo-recording medium is difficultly inhibited and that the
portion haying the different refractive index localized by the
holographic exposure is easily moved in the recording layer.
[0009] For improving such the drawback, a method by arranging a
supplemental member between the substrates constituting the
recording medium is proposed, for example, in U.S. Patent
Application Publication 2002/0145772. Such the method tends to be
insufficient for preventing the difference of layer thickness
between each of the recording media even though the method is
effective for preventing the positional discrepancy of the
substrates.
SUMMARY OF THE INVENTION
[0010] The object of the invention is to provide a method for
producing holographic recording media with small deformation and
high uniformity.
[0011] (1) An embodiment of the invention for attaining the above
object of the invention is a method for producing a holographic
recording medium having a holographic recording layer between a
first substrate and a second substrate in which the following
processes are successively performed,
[0012] a first recording layer forming composition providing
process for providing a holographic recording layer forming
composition onto the first substrate,
[0013] a holographic recording layer forming process for forming a
the holographic recording layer between the first substrate and the
second substrate by facing the second substrate to the first
substrate, and
[0014] a hardening process for hardening the holographic recording
layer by heat or light.
[0015] (2) The method for producing the holographic recording
medium of the invention described in (1), wherein the method
comprises a second recording layer forming composition providing
process for providing the holographic recording layer forming
composition onto the second substrate and a process for forming the
holographic recording layer between the first substrate and the
second substrate by facing the face of the first substrate on which
the holographic recording layer forming composition is provided and
the face of the second substrate on which the holographic recording
layer forming composition is provided.
[0016] (3) The method for producing the holographic recording
medium of the invention described in (1) or (2), wherein a first
space retaining means is provided for retaining a designated space
between the first substrate and the second substrate on the
occasion of the facing the second substrate and the first
substrate.
[0017] (4) The method for producing the holographic recording
medium of the invention described in any one of (1) through (3),
wherein the method comprises a substrate holding process for
holding the first substrate by the first substrate holding means or
the second substrate by the second substrate holding means, and a
process for forming the holographic recording layer between the
first substrate held by the first substrate holding means and the
second substrate held by the second substrate holding means by
facing the second substrate holding means to the first substrate
holding means.
[0018] (5) The method for producing the holographic recording
medium of the invention described in (4), wherein the first
substrate and the first substrate holding means are contacted by
vacuum in the substrate holding process.
[0019] (6) The method for producing the holographic recording
medium of the invention described in (4) or (5), wherein the second
substrate and the second substrate holding means are contacted by
vacuum in the substrate holding process.
[0020] (7) The method for producing the holographic recording
medium of the invention described in any one of (4) through (6),
wherein a second space retaining means is provided for retaining
the designated space between the first substrate holding means and
the second substrate holding means on the occasion of facing the
first substrate holding means to the second substrate holding
means.
[0021] (8) The method for producing the holographic recording
medium of the invention described in any one of (1) through (7),
wherein a removing means is provided for removing the holographic
recording layer forming composition forced out from the area of
facing the first substrate to the second substrate.
[0022] (9) The method for producing the holographic recording
medium of the invention described in any one of (1) through (8),
wherein the method comprises a cutting process for cutting the
holographic recording medium after the hardening process into a
designated size.
[0023] (10) The method for producing the holographic recording
medium of the invention described in any one of (1) through (9),
wherein the method comprises a sealing process for sealing the bare
portion of the holographic recording layer.
[0024] (11) The method for producing the holographic recording
medium of the invention described in any one of (1) through (10),
wherein a composition exhausting portion for exhausting the
holographic recording layer forming composition to outside of the
facing area of the first substrate and the second substrate is
provided at least one of the first substrate and the second
substrate.
[0025] (12) The method for producing the holographic recording
medium of the invention described in any one of (3) through (11),
wherein the composition exhausting portion for exhausting the
holographic layer forming composition to outside of the facing area
of the first substrate and the second substrate is provided at the
first space retaining means.
[0026] (13) The method for producing the holographic recording
medium of the invention described in any one of (1) through (12),
wherein the first recording layer forming composition providing
process and the holographic recording layer forming process are
performed under a reduced pressure.
[0027] (14) The method for producing the holographic recording
medium of the invention described in any one of (1) through (13),
wherein the method comprises a bubble removing process for removing
a bubble included in the holographic recording layer formed by the
holographic recording layer forming process.
[0028] (15) The method for producing the holographic recording
medium of the invention described in any one of (1) through (14),
wherein the holographic recording medium satisfies the relation of
0.15.ltoreq.Dh/(D1+D2).ltoreq.2.0 wherein D1 is the thickness of
the first substrate, D2 is the thickness of the second substrate
and Dh is the thickness of the holographic recording medium.
[0029] (16) The method for producing the holographic recording
medium of the invention described in (15), wherein the thickness of
the holographic recording layer Dh is from 200 .mu.m to 2.0 mm.
[0030] (17) The method for producing the holographic recording
medium of the invention described in (15), wherein the relation of
the thickness of the first substrate D1 and the thickness of the
second substrate D2 is D1.ltoreq.D2.
[0031] (18) The method for producing the holographic recording
medium of the invention described in any one of (1) through (17),
wherein the first substrate is transparent and subjected to an
anti-reflection treatment on the side opposite to the side on which
the holographic recording layer is provided.
[0032] (19) The method for producing the holographic recording
medium of the invention described in any one of (1) through (18),
wherein, the material of the first substrate is glass.
[0033] (20) The method for producing the holographic recording
medium of the invention described in any one of (1) through (19),
wherein a reflective layer having a reflectance of not less than
70% is provided on the face of the second substrate on which the
holographic recording layer to be provided or the face opposite
thereto.
[0034] (21) The method for producing the holographic recording
medium of the invention described in any one of (1) through (20),
wherein the shape of the holographic recording medium is a
disc.
[0035] (22) The method for producing the holographic recording
medium of the invention described in any one of (1) through (21),
wherein the shape of the holographic recording medium is a
card.
[0036] (23) An embodiment of the invention is a method for
producing a holographic recording medium having a holographic
recording layer between a first substrate and a second substrate in
which the following processes are successively performed,
[0037] a space forming process for forming a space between the
first substrate and the second substrate having at least one
opening through which the holographic recording layer forming
composition is charged into the space by holding the first
substrate and the second substrate so the designated distance is
retained between the substrates,
[0038] a recording layer forming composition charging process for
charging the holographic recording layer composition into the space
through the at least one opening to form the holographic recording
layer, and
[0039] a hardening process for hardening the holographic recording
layer by heat or light.
[0040] (24) The method for producing the holographic recording
medium of the invention described in (23), wherein the holographic
recording layer forming composition is charged into the space by
injecting the composition through the opening.
[0041] (25) The method for producing the holographic recording
medium of the invention described in any one of (23) or (24),
wherein the opening has an injection portion through which the
holographic recording layer forming composition is injected into
the space and a exhausting portion through which the holographic
recording layer forming composition is exhausted from the space and
the holographic recording layer forming composition is charged into
the space by sucking air through the exhausting portion in the
holographic recording layer forming composition charging
process.
[0042] (26) The method for producing the holographic recording
medium of the invention described in any one of (23) through (25),
wherein a first space retaining means is provided for holding the
first substrate and the second substrate so as to retain the
designated distance between the first and second substrates.
[0043] (27) The method for producing the holographic recording
medium of the invention described in any one of (23) through (26),
wherein the method comprises a substrate holding process for
folding the first substrate by a first substrate holding means
and/or folding the second substrate by a second substrate holding
means, and the first substrate and the second substrate are faced
to each other so as to retain the designate distance between the
first substrate and the second substrate and the space having at
least one opening for charging the holographic recording layer
forming composition in the space forming process.
[0044] (28) The method for producing the holographic recording
medium of the invention described in (27), wherein the first
substrate and the first substrate holding means are contacted by
vacuum in the substrate holding process.
[0045] (29) The method for producing the holographic recording
medium of the invention described in any one of (27) through (28),
wherein the second substrate and the second substrate holding means
are contacted by vacuum in the substrate holding process.
[0046] (30) The method for producing the holographic recording
medium of the invention described in any one of (27) through (29),
wherein a second space retaining means is provided for retaining a
designated space between the first substrate holding means and the
second substrate holding means on the occasion of facing the first
substrate holding means to the second substrate holding means.
[0047] (31) The method for producing the holographic recording
medium of the invention described in any one of (23) through (30),
wherein a removing means is provided for removing the holographic
recording layer forming composition forced out from the area of
facing the first substrate to the second substrate.
[0048] (32) The method for producing the holographic recording
medium of the invention described in any one of (23) through (31),
wherein the method comprises a cutting process for cutting the
holographic recording medium after the hardening process into a
designated size.
[0049] (33) The method for producing the holographic recording
medium of the invention described in any one of (23) through (32),
wherein, the method comprises a sealing process for sealing the
bare portion of the holographic recording layer.
[0050] (34) The method for producing the holographic recording
medium of the invention described in any one of (23) through (33),
wherein a holographic recording layer forming composition charging
portion for charging the holographic recording layer forming
composition into the space and a holographic recording layer
forming composition exhausting portion for exhausting the
holographic recording layer forming composition from the space are
provided on at least one of the first substrate and the second
substrate.
[0051] (35) The method for producing the holographic recording
medium of the invention described in any one of (23) through (34),
wherein a holographic recording layer forming composition charging
portion for charging the holographic recording layer forming
composition into the space and a holographic recording layer
forming composition exhausting portion for exhausting the
holographic recording layer forming composition from the space are
provided on the first space retaining means.
[0052] (36) The method for producing the holographic recording
medium of the invention described in any one of (23) through (35),
wherein the recording layer forming composition charging process is
performed under a reduced pressure.
[0053] (37) The method for producing the holographic recording
medium of the invention described in any one of (23) through (36),
wherein the method comprises a bubble removing process for removing
a bubble included in the holographic recording layer formed by the
holographic recording layer forming process.
[0054] (38) The method for producing the holographic recording
medium of the invention described in any one of (23) through (37),
wherein the holographic recording medium satisfies the relation of
0.15.ltoreq.Dh/(D1+D2).ltoreq.2.0 wherein D1 is the thickness of
the first substrate, D2 is the thickness of the second substrate
and Dh is the thickness of the holographic recording medium.
[0055] (39) The method for producing the holographic recording
medium of the invention described in (38), wherein the thickness of
the holographic recording layer Dh is from 200 .mu.m to 2.0 mm.
[0056] (40) The method for producing the holographic recording
medium of the invention described in (38) or (39), wherein the
relation of the thickness of the first substrate D1 and the
thickness of the second substrate D2 is D1.ltoreq.D2.
[0057] (41) The method for producing the holographic recording
medium of the invention described in any one of (23) through (40),
wherein the first substrate is transparent and subjected to an
anti-reflection treatment on the side opposite to the side on which
the holographic recording layer is provided.
[0058] (42) The method for producing the holographic recording
medium of the invention described in any one of (23) through (41),
wherein, the material of the first substrate is glass.
[0059] (43) The method for producing the holographic recording
medium of the invention described in any one of (23) through (42),
wherein a reflective layer having a reflectance of not less than
70% is provided on the face of the second substrate on which the
holographic recording layer to be provided or the face opposite
thereto.
[0060] (44) The method for producing the holographic recording
medium of the invention described in any one of (23) through (43)
wherein the shape of the holographic recording medium is a
disc.
[0061] (45) The method for producing the holographic recording
medium of the invention described in any one of (23) through (44)
wherein the shape of the holographic recording medium is a
card.
[0062] (46) An embodiment of the invention is a method for
producing the holographic recording medium having a holographic
recording layer between a first substrate and a second substrate in
which the following processes are successively performed,
[0063] a space forming process for forming a space between the
first substrate and the second substrate having at least one
opening through which the holographic recording layer forming
composition is charged into the space by holding the first
substrate and the second substrate so the designated distance is
retained between the substrates,
[0064] a pressure reducing process for reducing pressure in the
space by a pressure controlling means,
[0065] a recording layer forming process in which the holographic
recording layer is formed by charging the holographic recording
layer forming composition into the space through at least one of
the opening by restoring the pressure in the space to the original
pressure by the pressure controlling means, and
[0066] a hardening process for hardening the holographic recording
layer by heat or light.
[0067] (47) The method for producing the holographic recording
medium of the invention described in (46), wherein the opening is
immersed in the holographic recording layer forming composition and
then the holographic recording layer forming composition is charged
into the space through the opening by restoring the pressure in the
space reduced in the pressure reducing process by the pressure
controlling means.
[0068] (48) The method for producing the holographic recording
medium of the invention described in (46), wherein the holographic
recording layer forming composition is charged into the space while
the reduced pressure in the space is maintained.
[0069] (49) The method for producing the holographic recording
medium of the invention described in any one of (46) through (48),
wherein the method comprises a substrate holding process for
holding the first substrate by the first substrate holding means or
the second substrate by the second substrate holding means, and in
the space forming process, the first substrate and the second
substrate are each held so as that the distance between the first
substrate and the second substrate is made to a designated distance
and the space having at least one opening for charging the
holographic recording layer forming composition between the first
substrate and the second substrate is formed by facing the second
substrate holding means to the first substrate holding means.
[0070] (50) The method for producing the holographic recording
medium of the invention described in (49), wherein the first
substrate and the first substrate holding means are contacted by
vacuum in the substrate holding process.
[0071] (51) The method for producing the holographic recording
medium of the invention described in (49), wherein the second
substrate and the second substrate holding means are contacted by
vacuum in the substrate holding process.
[0072] (52) The method for producing the holographic recording
medium of the invention described in (49) through (51), wherein a
second space retaining means is provided for retaining a designated
space between the first substrate and the second substrate on the
occasion of the facing the second substrate and the first
substrate.
[0073] (53) The method for producing the holographic recording
medium of the invention described in anyone of (46) through (52),
wherein a removing means is provided for removing the holographic
recording layer forming composition forced out from the area of
facing the first substrate to the second substrate.
[0074] (54) The method for producing the holographic recording
medium of the invention described in any one of (46) through (53),
wherein the method comprises a cutting process for cutting the
holographic recording medium into a designated size after the
hardening process.
[0075] (55) The method for producing the holographic recording
medium of the invention described in any one of (46) through (53),
wherein the method comprises a sealing process for sealing the bare
portion of the holographic recording layer.
[0076] (56) The method for producing the holographic recording
medium of the invention described in any one of (46) through (55),
wherein the holographic recording medium satisfies the relation of
0.15.ltoreq.Dh/(D1+D2).ltoreq.2.0 wherein D1 is the thickness of
the first substrate, D2 is the thickness of the second substrate
and Dh is the thickness of the holographic recording medium.
[0077] (57) The method for producing the holographic recording
medium of the invention described in (56), wherein the thickness of
the holographic recording layer Dh is from 200 .mu.m to 2.0 mm.
[0078] (58) The method for producing the holographic recording
medium of the invention described in (56) or (57), wherein the
relation of the thickness of the first substrate D1 and the
thickness of the second substrate D2 is D1.ltoreq.D2.
[0079] (59) The method for producing the holographic recording
medium of the invention described in any one of (46) through (58),
wherein the first substrate is transparent and subjected to an
ant-reflection treatment on the side opposite to the side on which
the holographic recording layer is provided.
[0080] (60) The method for producing the holographic recording
medium of the invention described in any one of (46) through (59),
wherein, the material of the first substrate is glass.
[0081] (61) The method for producing the holographic recording
medium of the invention described in anyone of (46) through (60),
wherein a reflective layer having a reflectance of not less than
70% is provided on the face of the second substrate on which the
holographic recording layer to be provided or the face opposite
thereto.
[0082] (62) The method for producing the holographic recording
medium of the invention described in any one of (46) through (61),
wherein the shape of the holographic recording medium is a
disc.
[0083] (63) The method for producing the holographic recording
medium of the invention described in any one of (46) through (62),
wherein the shape of the holographic recording medium is a
card.
[0084] (64) The method for producing the holographic recording
medium of the invention described in any one of (46) through (63),
wherein the method comprises a bubble removing process for removing
a bubble included in the holographic recording layer formed by the
holographic recording layer forming process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0085] FIGS. 1(a) through 1(d) show schematic drawings describing
the usual production method of a holographic recording medium.
[0086] FIGS. 2(a) through 2(d) show schematic drawings describing
the first embodiment of the production method according to the
invention of a holographic recording medium.
[0087] FIGS. 3(a) through 3(j) show schematic drawings describing
the first embodiment of the production method according to the
invention of a holographic recording medium.
[0088] FIGS. 4(a) through 4(k) show schematic drawings describing
the first embodiment of the production method according to the
invention of a holographic recording medium.
[0089] FIG. 5 shows the cross section of the substrate piled with
the substrate holding means shown in FIGS. 3(a) through 3(j) of the
first embodiment of the holographic recording medium producing
method according to the invention.
[0090] FIG. 6 shows the cross section of the substrate piled with
the substrate holding means shown in FIGS. 4(a) through 4(k) of the
first embodiment of the holographic recording medium producing
method according to the invention.
[0091] FIG. 7 shows the plan view of the upper side of the means
for retaining the distance from the outer side of the disc-shaped
first substrate to the outer side of the second substrate at the
designated value in the first embodiment of the holographic
recording medium producing method according to the invention.
[0092] FIGS. 8(a) through 8(e) show the enlarged drawing of a part
of the means shown in FIG. 7 in the first embodiment of the
holographic recording medium producing method according to the
invention.
[0093] FIGS. 9(a) through 9(e) show the means for retaining the
distance from the inner side of the first substrate to the inner
side of the second substrate at the designated value in the first
embodiment of the holographic recording medium producing method
according to the invention.
[0094] FIGS. 10(a) and 10(b) show the cross section of the
combination of the first space retaining means, the first substrate
and the second substrate in the first embodiment of the holographic
recording medium producing method according to the invention.
[0095] FIGS. 11(a) through 11(b) show the drawings describing the
first embodiment of the holographic recording medium producing
method according to the invention.
[0096] FIGS. 12(a) through 12(e) show the drawings describing the
first embodiment of the holographic recording medium producing
method according to the invention.
[0097] FIGS. 13(a) through 13(c) show the drawings describing the
second embodiment of the holographic recording medium producing
method according to the invention.
[0098] FIGS. 14(a) through 14(g) show the drawings describing the
second embodiment of the holographic recording medium producing
method according to the invention.
[0099] FIGS. 15(a) through 15(h) show the drawings describing the
second embodiment of the holographic recording medium producing
method according to the invention.
[0100] FIGS. 16(a) through 16(c) show the drawings describing the
second embodiment of the holographic recording medium producing
method according to the invention.
[0101] FIGS. 17(a) through 17(g) show drawings describing the
situation in which each of the substrates is contacted to the face
of the corresponding substrate holding means for holding the
substrate and the substrate holding means are pile by pressure with
together.
[0102] FIGS. 18(a) through 18(j) show the method for charging the
holographic recording layer forming composition into the designated
space between the substrates formed by the space retaining means
and the substrate holding means shown in FIG. 17.
[0103] FIGS. 19(a) and 19(b) show the substrate holding means
capable producing plural holographic recording media.
[0104] FIGS. 20(a) through 20(c) show examples of substrate with
the space retaining means.
[0105] FIGS. 21(a) and 21(b) show an example of the production
method using an element in which the space is retained by firmly
connected the first substrate, the space retaining means and the
second substrate.
[0106] FIG. 22 shows the recording media without the recording
layer and connected in series by connecting pipes.
[0107] FIG. 23 shows an example of the arrangement for charging the
recording layer forming composition to the recording media without
recording layer connected in series by the connecting pipes.
[0108] FIGS. 24(a) through 24(e) show an example using a ultrasonic
vibrator as the bubble removing means.
[0109] FIGS. 25(a) through 25(i) show an example of the removing
means for removing the holographic recording layer forming
composition forced out from the substrate.
[0110] FIGS. 26(a) and 26(b) show the removing means capable of
treating plural media.
[0111] FIGS. 27(a) and 27(b) show an example of tool for sealing
the bare portion of the holographic recording layer.
[0112] FIGS. 28(a) through 28(i) show the concrete sealing
procedure using the sealing tool and the sealing material.
[0113] FIGS. 29(a) through 29(e) show the structure of recording
medium without holographic recording layer forming composition
which is constituted by the first and second substrates held
between the space retaining means.
[0114] FIGS. 30(a) through 30(f) show the drawings describing the
third embodiment of the holographic recording medium producing
method according to the invention.
[0115] FIGS. 31(a) through 31(e) show the structure of recording
medium without holographic recording layer forming composition
which is constituted by the first and second substrates held
between the space retaining means.
[0116] FIGS. 32(a) through 32(c) show the substrate holding
means.
[0117] FIGS. 33(a) and 33(b) show the recording medium without the
recording layer set by using the substrate holding means.
[0118] FIGS. 34(a) through 34(f) show the drawings describing the
third embodiment of the holographic recording medium producing
method according to the invention.
[0119] FIGS. 35(a) through 35(e) show the hardening method by
uniformly irradiating light to the recording medium.
[0120] FIGS. 36(a) through 36(d) show the hardening method by a
heating treatment.
THE BEST EMBODIMENT OF THE INVENTION
[0121] The embodiments of the invention are described in detail
below referring FIGS. 1 through 36.
[0122] FIGS. 1(a) through 1(d) are schematic drawings describing
the usual production method of a holographic recording medium.
[0123] Generally, holographic recording medium is prepared by the
following procedure: a holographic recording layer forming
composition 102 is provided on a first substrate 101 shown in FIG.
1(a) and pasted with a second substrate 103 shown in FIG. 1(c) to
prepare a holographic recording medium 100 in which the first
substrate shown in FIG. 1(d), the holographic recording layer and
the second substrate are piled in this order. However, degradation
of the uniformity of the thickness of the recording layer of
individual recording medium or the fluctuation of the recording
layer thickness of every recording media tends to occur, even
though some countermeasure are proposed, since the recording layer
of such the recording medium is thicker than that of usual
recording media.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The First Embodiment of the Invention
[0124] FIGS. 2(a) through 2(d), FIGS. 3(a) through 3(j) and FIGS.
4(a) through 4(k) are all drawings describing the first embodiment
of the production method of holographic recording medium according
to the invention. First, FIGS. 2(a) through 2(d) and FIGS. 3(a)
through 3(j) are described.
[0125] In FIGS. 2(a) through 2(d), 201 is a first substrate holding
means, 220 is a second substrate holding means, 230 is a first
substrate, 240 is a second substrate, 211 is a space retaining
means (the second space retaining means) for keeping the space
between the first substrate holding means 210 and the second
substrate holding means 220, 214 is a dent fitting with the shape
of the first substrate 230, 212 is a suction opening for contacting
the first substrate 230 to the dent 214, 215 is the face to be
contacted with the second substrate holding means 220, 213 is a
dent for position adjusting of the first substrate holding means
and the second substrate holding means, 221 and 223 are projections
for position adjusting of the first substrate holding means and the
second substrate holding means, 224 is a projection fitting with
the shape of the second substrate 240, 222 is a suction opening for
contacting the second substrate 240 to the projection 224, 225 is
the face to be contacted to the first substrate holding means 210,
and 241 and 242 are each a exhausting portion for exhausting
excessive recording layer forming composition which are also
effective as the space forming means for forming a designated space
between the first substrate holding means 210 and the second
substrate holding means 220 when they are combined. FIG. 2(a) is a
front view of the first substrate holding means, FIG. 2 (b is a
front view of the second substrate holding means, and FIG. 2(c) and
FIG. 2(d) are each a plan view of the first substrate 230 and the
second substrate 240.
[0126] In FIGS. 3(a) through 3(j), 310 is a first substrate holding
means, 320 is a second substrate holding means, 330 is a first
substrate, 340 is a second substrate, 311 is a space retaining
means for retaining the space between the first substrate holding
means 410 and the second substrate holding means 320, 314 is a dent
fitting with the shape of the first substrate 330, 321 is a suction
opening for contacting the first substrate 330 to the dent 314, 315
is the face to be contacted with the second substrate holding
means, 313 is a dent for position adjusting of the first substrate
holding means and the second substrate holding means, 321 and 323
are each a projection for position adjusting of the first substrate
holding means and the second substrate holding means, 324 is a
projection fitting with the shape of the second substrate 340, 322
is a suction opening for contacting the second substrate 340 to the
projection 324, 325 is the face to be contacted to the first
substrate holding means 310, 341 and 342 are a exhausting portion
for exhausting excessive recording layer forming composition and
350 and 351 represent the holographic recording layer forming
composition.
[0127] First, the first substrate holding means 310 and the first
substrate 330 are prepared as shown in FIG. 3(a) and the first
substrate 330 is put into the dent 314 having the shape fitting
with that of the first substrate as shown in FIG. 3(b). It is
preferred on this occasion that the first substrate 330 is
contacted to the dint 314 by sucking through the suction opening
312 for reducing the unevenness of the holographic recording layer
thickness. Then the holographic recording layer forming composition
350 is coated on the first substrate by a recording layer forming
composition providing means as shown in FIG. 3(c). Besides, the
second substrate holding means 320 and the second substrate are
prepared as shown in FIG. 3(d), and the second substrate is
contacted to the dent 324 by sucking through the suction opening
322 as shown in FIG. 3(e). Then the holographic recording layer
forming composition 351 is coated on the first substrate by the
recording layer forming composition providing means. Lastly, the
first substrate and the second substrate, on each of which the
holographic recording layer forming composition are coated, are
piled and pressed as shown in FIG. 3(f). Thus, the recording medium
having the holographic recording layer of designated thickness can
be produced. FIG. 3(g) shows the method for directly piling the
second substrate to the first substrate coated with the holographic
recording layer forming composition 350 by the recording layer
forming composition providing means shown in FIG. 3(c). FIG. 3(h)
shows the piled state of the second substrate 340 and the first
substrate coated with the recording layer forming composition 350,
and FIG. 3(j) shows the method by which the second substrate
holding means 320 shown in FIG. 3(i) is piled and pressed to
produce the recording medium with the holographic recording layer
having the designated thickness. For inhibiting the fluctuation of
the recording layer thickness while maintaining the uniformity of
the whole thickness of any portion of the medium, it is preferable
that the second substrate is contacted to the projection 324 for
position adjusting to the second substrate holding means by sucking
through the suction opening 332 formed on the second substrate
holding means 320 shown in FIG. 3(j). Furthermore, the fluctuation
of the layer thickness between individual recording media can be
reduced since the substrate holding means commonly can be used.
[0128] As the recording layer forming composition providing means,
any methods capable of coating the recording layer forming
composition on the substrate can be applied without any limitation.
Known coating methods such as direct drip coating, brush coating,
coating by a coating station such as a roller coater, coating by an
ink-jet nozzle or gravure coating can be optionally applied.
[0129] The production method using the substrate holding means each
fitted to the shape of the first and second substrate,
respectively, is described referring FIGS. 3(a) through 3(j), and
an example of the method using substrate holding means having the
shape different from that of the substrate is described in FIGS.
4(a) through 4(k). In FIGS. 4(a) through 4(k), 410 is a first
substrate holding means, 420 is a second substrate holding means,
430 is a first substrate, 440 is a second substrate, 450 is a
holographic recording layer forming composition, 411 is a space
retaining means for retaining the designated space on the occasion
of contacting with the second substrate holding means, 412 is a
suction opening for contacting the first substrate, 413 is a
portion to be contacted to the first substrate, 414 is a exhausting
means for exhausting the composition when the excessive composition
is brought, 421 is a space retaining means for retaining the
designated space on the occasion of contacting with the first
substrate holding means, 422 is a suction opening for contacting
the second substrate, and FIGS. 4(a) and 4(b) each show the first
substrate and the first substrate holding means and FIGS. 4(g) and
4(h) each shows the second substrate and the second substrate
holding means, respectively.
[0130] Firstly, the first substrate 340 is contacted by vacuum with
the first substrate holding means 410 by sucking through the
suction opening 412 as shown in FIGS. 4(c) and 4(d). FIG. 4(c) is a
plan view from the upper viewpoint and FIG. 4(d) is a plan view
from the side viewpoint. In such the state, the holographic
recording layer forming composition 450 is coated onto the first
substrate contacted by vacuum to the first substrate holding means
by the recording layer composition providing means as shown in
FIGS. 4(e) and 4(f), on which the second substrate 440 contacted by
vacuum to the second substrate holding means 420 by sucking through
the suction opening 422 as shown in FIGS. 4(i) and 4(j) is piled
and pressed. Thus the recording media can be produced which have
each a uniform whole thickness at any portion thereof and the
uniform designated thickness of the recording layer. Moreover, the
fluctuation of the layer thickness between the individual recording
media can be reduced since the substrate holding means commonly can
be used.
[0131] FIG. 5 shows the cross section of the substrate and the
substrate holding means shown in FIGS. 3(a) through 3(j) in the
piled state, and FIG. 6 shows the cross section of the substrate
and the substrate holding means shown in FIGS. 4(a) through 4(k) in
the piled state.
[0132] As is cleared in FIG. 5, in the production method shown by
FIGS. 3(a) through 3(j), it is preferable that the recording layer
forming composition is coated in the same or a slightly excessive
amount to the amount to be charged into the space and the
composition has low viscosity since the capacity of the exhausting
means is small in the substrate holding means.
[0133] In the method shown by FIGS. 4(a) through 4(k), the
substrate holding means has large capacity for receiving the
excessive recording layer forming composition, accordingly it is
preferable that the composition is coated in an excessive amount,
and the recording medium can be produced even when the composition
has high viscosity.
[0134] Next, the producing method is described in which the
holographic recording medium using the space retaining means for
holding the first and second substrates so as to retain the
designated space between each of the substrates.
[0135] The space retaining means (the first space retaining means)
to be used in the production method according to the invention is
described in detail referring FIG. 7, FIGS. 8(a) through 8(e) and
FIGS. 9(a) through 9(e).
[0136] FIG. 7 is a plan view from the upper viewpoint of the means
for retaining the distance between the outer side of shaped
substrate disc and that of the second substrate disc at the
designated value, and the space retaining means 760 has a space
keeping means 710.
[0137] FIGS. 8(a) through 8(e) show the enlarged drawings of a part
of the means shown by FIG. 7. In the drawings, some shapes of the
means are shown. However, the shape is not limited to those
described below.
[0138] In FIGS. 8(a) through 8(e), the drawings shown in the upper
line are each the plan view from the upper viewpoint, those shown
in the intermediate line are plan view from the inside viewpoint
and those shown in the lower line are the cross section from the
side viewpoint. In the drawings, 810, 820, 830, 840 and 850 are
each a portion for retaining the designated distance between the
outer side of the first substrate and that of the second substrate,
811, 821, 831, 941 and 851 are each a face to be contacted to the
first substrate, 812, 822, 832, 842 and 825 are each a face to be
contacted to the second substrate, 823, 824, 834, 844, 845 and 855
are each a portion for exhausting the excessive recording layer
forming composition, 856 is a claw for contacting the first
substrate to the portion 851 of the space retaining means to be
contacted to the substrate, and 857 is a claw for contacting the
second substrate to the portion 852 of the space retaining means to
be contacted to the substrate.
[0139] FIGS. 9(a) through 9(e) show means for retaining the
distance between the inner side of the first substrate and that of
the second substrate. In FIGS. 9(a) through 9(e), the drawing in
the upper line are the plan view from the upper viewpoint, those in
the lower line are cross section from the side viewpoint. In the
drawings, 910, 920, 930, 940 and 950 are each a space retaining
means, 911, 921, 931, 941 and 951 are each a space retaining means
for retaining the distance between the inner side of the first
substrate and that of the second substrate at the designated value,
912, 922, 923, 932 and 933 are each a portion for exhausting the
excessive recording layer forming composition and the 954 and 955
are each a claw for contacting the first substrate and the second
substrate to the space retaining means. The shape of the means for
retaining the distance between the inner side of the first
substrate and that of the second substrate at the designated value
to produce the disc-shaped recording medium is not limited to the
shapes shown in the drawings as long as the space retaining means
can attain the object of the invention.
[0140] FIGS. 10(a) and 10(b) show each the cross section of the
space retaining means, the first substrate and the second substrate
in the assembled state shown in FIGS. 8(a) through 8(e) and FIGS.
9(a) through 9(e). In FIGS. 10(a) and 10(b), 1040 and 1080 are each
a means for retaining the distance between the outer side of the
first substrate and that of the second substrates, 1030 and 1070
are each a means for retaining the distance between the inner side
of the first substrate and that of the second substrate, 1010 and
1050 are each a first substrate, and 1020 and 1060 are each a
second substrate.
[0141] An example of the production method is described below
referring the FIGS. 11(a) through 11(h) in which the
above-described space retaining means is used.
[0142] In FIGS. 11(a) through 11(h), 1110 is a first substrate
holding means, 1111 is a suction opening for contacting the first
substrate to the first substrate holding means, 1120 is a first
substrate, 1130 is an outer side space retaining means, 1140 is an
inner side space retaining means, 1141 is a portion for exhausting
the excessive recording layer forming composition, 1150 is a
holographic recording layer forming composition, 1160 is a second
substrate, 1161 is a portion for exhausting the excessive recording
layer forming composition from the inner space retaining means,
1162 is the portion for exhausting the excessive recording layer
forming composition from the outer space retaining means, 1170 is a
second substrate holding means, 1171 is a suction opening for
contacting the second substrate to the second substrate holding
means, 1172 is a portion for exhausting the excessive recording
layer forming composition from the outer side of the recording
medium, 1173 is a portion for exhausting the excessive recording
layer forming composition from the inner side of the recording
medium. Firstly, the first substrate 1120 shown by FIG. 11(b) is
contacted by vacuum to the first substrate holding means 1110, and
then the outer space retaining means 1130 and inner space retaining
means 1140 are piled for maintaining the distance between the first
substrate and the second substrate as shown in FIGS. 11(c) and
11(d). In such the situation, the holographic recording layer
forming composition 1150 is coated and the second substrate is
softly piled on the space retaining means as shown in FIG. 11(f).
Lastly, the second space retaining means 1170 is piled as shown in
FIGS. 11(g) and 11(h) and pressure is applied while the second
substrate 1160 is contacted by vacuum by sucking through the
suction opening 1171. Thus the recording media can be produced
which have each a uniform whole thickness at any portion thereof
and the uniform designated thickness of the recording layer.
Moreover, the fluctuation of the layer thickness between the
individual recording media can be reduced since the substrate
holding means commonly can be used.
[0143] Next, an example of the method for producing the holographic
recording media having an optional shape is described below
referring FIGS. 12(a) through 12(e).
[0144] In FIGS. 12(a) through 12(e), 1210 is a first substrate,
1220 is a holographic recording layer forming composition, 1130 is
a second substrate. Firstly, the recording layer forming
composition 1220 is coated on the first substrate 1210 as shown in
FIG. 12(a), and the second substrate is piled and the distance
between the first and second substrates is retained at the
designated value as shown in FIGS. 12(b) and 12(c). Then the piled
matter is successively subjected to the bubble removing treatment
for removing air bubbles included in the holographic recording
layer, the hardening treatment by heating or irradiation of light
having wavelength different from that of the light to be used for
holographic recording exposure as later-described. Thereafter, the
recording layer is cut together with the substrates by irradiation
of laser light beams 1240 and 1241. Thus the disc-shaped recording
medium as shown in FIG. 12(a) can be produced. Any laser light can
be used for the above purpose without any limitation as long as
laser light is high power capable of cutting the piled matter. The
cutting treatment either may be performed until the object is
completely cut or until a degree of deepness so that the desired
shaped recording medium can be easily taken off. The number of the
laser light beam either may be one or more. The laser light beam
may be irradiated from the side of the first substrate side, the
second substrate side or the both sided of the piled matter. The
angle of the laser light beam with the substrate is preferably from
50.degree. to 90.degree.. When the cutting is performed by the
laser light beam, the piled matter may be protected to degradation
of the recording surface caused by the laser light by a light
shield protecting material. As the method for piling the
holographic recording layer having the designated thickness between
the substrates shown in FIGS. 12(a) through 12(e), for example, the
producing equipment as shown FIGS. 4(a) through 4(k) can be applied
in which the space is retained at only outer side of the substrate
holding means.
[0145] In the above-mentioned first embodiment of the production
method, the formation of the space and the provision of the
recording layer forming composition are preferably performed under
reduced pressure for inhibiting the mixing of bubbles into the
holographic recording layer as possible as small. The reduced
pressure is preferably from 0.05 kPa to 80 kPa, and more preferably
from 0.1 kPa to 50 kPa, compared with the ordinary atmosphere
pressure. Moreover, according to the kind of the holographic
recording layer forming composition, the reduced pressure
atmosphere prepared by reducing pressure after replacement of the
air by inactive gas such as nitrogen or argon or the dried air is
suitably utilized.
[0146] The reduced pressure is preferably from 0.05 kPa to 80 kPa,
and more preferably from 0.1 kPa to 50 kPa, compared with the
ordinary atmosphere pressure. Moreover, according to the kind of
the holographic recording layer forming composition, the reduced
pressure atmosphere prepared by reducing pressure after replacement
of the air by inactive gas such as nitrogen or argon or the dried
air is suitably utilized.
[0147] By the production method exemplified by the foregoing FIGS.
3(a) through 3(j), FIGS. 4(a) through 4(k), and FIGS. 11(a) through
11(h), only one of the holographic recording medium can be produced
at once. However, plural of the recording media can be
simultaneously produced by the use of the substrate holding means
suited for the production of the plural recording media such as
that later-described by FIGS. 19(a) and 19(b).
[0148] The above-described hardening process essential in the first
embodiment, the bubble removing process provided according to the
necessity, the removing process for removing the holographic
recording layer forming composition forced out from the substrate
and the sealing process for sealing the bare portion of the of the
holographic recording layer are described in the description of the
second embodiment since such the process are the same as those in
the later-described second embodiment.
The Second Embodiment of the Invention
[0149] FIGS. 13(a) through 13(c), FIGS. 14(a) through 14(g) and
FIGS. 15(a) through 15(h) show an example of the production of the
recording media using the substrate holding means for holding the
first and second substrates so as to make the designated distance
between the substrates.
[0150] The first substrate and the second substrate each held by
the substrate holding means so as to retain the designated space
between them as shown in the drawings, and to such the state, a
recording layer forming composition ejecting means or a recording
layer forming composition sucking means each for charging the
recording layer forming composition into the space between the
first and second substrate is provided.
[0151] Among the above drawings, FIGS. 13(a) through 13(c) are each
a scheme of the first and the second substrate holding means,
respectively, and 13(b) is a cross section of the first and the
second substrate holding means in the piled state. In FIGS. 13(a)
through 13(c), 1300 is a first substrate holding means, 1301 and
1302 are each a face to be contact to the second substrate holding
means, 1301 is a second substrate holding means, 1311 and 1312 are
each a face to be contact to the first substrate holding means,
1303 and 1313 are each a face for each of the substrate, 1304 and
1314 are each a suction opening for contacting the each of the
substrates by vacuum, 1306 and 1316 are each a portion through
which the recording layer forming composition is injected into the
space between the substrates, 1307 is a control valve on the side
of exhausting the composition from the space between the substrates
and 1308 is a control valve on the side of charging the composition
into the space between the substrates.
[0152] FIGS. 14(a) through 14(g) and FIGS. 15(a) through 15(h)
describe an example of production method using the substrate
holding means for keeping the distance between the first substrate
and the second substrate shown in FIGS. 13(a) through 13(c) at the
designated value. FIGS. 14(a) through 14(g) show the piled state in
which the substrates each are contacted by vacuum to the substrate
holding face of the corresponding substrate holding means and the
substrate holding means are piled with together by pressing. In
FIGS. 14(a) through 14(g), 1420 is a first substitute, 1430 is a
second substrate, 1400 is a first substrate holding means, 1410 is
the second substrate holding means, 1407 is a control valve on the
exhausting side through which the holographic recording layer
forming composition is exhausted from the space between the
substrates, 1408 is a control valve on the charging side through
which the holographic recording layer forming composition is
injected between the substrates. FIG. 14(a) shows the first
substrate, FIG. 14(b) shows the first substrate holding means, and
FIG. 14(c) shows the state of first substrate contacted to the
first substrate holding means by vacuum. FIG. 14(d) shows the
second substrate, FIG. 14(e) shows the second substrate holding
means, FIG. 14(f) shows a plan view of the second substrate
contacted by vacuum to the second substrate holding means, and FIG.
14(g) shows a cross section of the piled state in which the
substrate holding means each holding the substrate are piled by
pressure.
[0153] FIGS. 15(a) through 15(h) show the method for charging the
holographic recording layer forming composition into the space
having the designated width formed by the substrate holding means
shown in FIGS. 14(a) through 14(g). In FIGS. 15(a) through 15(h),
1500 is a first substrate holding means, 1510 is a second substrate
holding means, 1507 is a control valve on the exhausting side
through which the holographic recording layer forming composition
is exhausted from the space between the substrates, 1508 is a
control valve on the charging side through which the holographic
recording layer forming composition is injected between the
substrates, 1540 is a holographic recording layer forming
composition to be charged. FIGS. 15(a) and 15(b) show the situation
in which the charging of the holographic recording layer forming
composition is started by applying pressure to the composition,
FIGS. 15(c) and 15(d) show the situation in which the composition
is charged until half of the substrate, FIGS. 15(e) and 15(f) show
the state in which the space between the substrates is filled up by
the composition, and FIGS. 15(g) and 15(h) are the scheme of the
situation in which the valve on the charging side is closed for
stopping the supply of the composition. FIGS. 15(a), 15(c), 15(e)
and 15(g) are each a scheme of the horizontal cross section of the
substrate holding means in a state of piled by pressure for
convenience of the explanation, and FIGS. 15(b), 15(d), 15(f) and
15(h) are each a scheme of the vertical cross section of the
substrate holding means piled by pressure for convenience of the
explanation.
[0154] The recording media can be produced which have each a
uniform whole thickness at any portion thereof and the uniform
designated thickness of the recording layer and the fluctuation of
the layer thickness between the individual recording media can be
reduced since the substrate holding means commonly can be used when
the recording layer forming composition is charged between the
substrates by applying the recording layer forming composition
charging means shown by FIGS. 15(a) through 15(h).
[0155] FIGS. 16(a) through 16(c), FIGS. 17(a) through 17(g) and
FIGS. 18(a) through 18(j) show an example of recording media
producing method using the space retaining means for folding the
first and second substrates so as to retain the designated space
between the substrates and the substrate folding means.
[0156] FIG. 16(a) is the scheme of the first substrate holding
means and FIG. 16(c) is that of the second substrate holding means,
and FIG. 16(b) is the cross section of the combined state of the
first substrate holding means and the second substrate holding
means. In FIGS. 16(a) through 16(c), 1600 is a first substrate
holding means, 1601 is the face to be contact to the second
substrate holding means, 1610 is the second substrate holding
means, 1611 is a face to be contacted to the first substrate
holding means, 1603 and 1613 are each a face for holding the
substrate, 1606 and 1616 are each a portion through which the
holographic recording layer forming composition is injected between
the substrates, 1605 and 1615 are each the portion through which
the composition is discharged from the space between the
substrates, 1607 is a control valve on the side of exhausting the
composition from the space between the substrates and 1608 is a
control valve on the side of charging the composition into the
space between the substrates.
[0157] FIGS. 17(a) through 17(g) and FIGS. 18(a) through 18(j) show
an example of recording media production using the space retaining
means for holding the first substrate and the second substrate so
as to make the designated space between the substrates shown by
FIGS. 16(a) through 16(c) and the substrate holding means for each
of the substrate, and FIGS. 17(a) through 17(g) show the state in
which the substrates are each contacted to the corresponding
substrate holding face of the substrate holding means through the
space retaining means and piled with pressure. In FIGS. 17(a)
through 17(g), 1720 is a first substrate, 1730 is a second
substrate, 1750 is a space retaining means for holding the outer
side of the substrate so as to retain the designated space, 1760 is
a second substrate, 1750 is a space retaining means for holding the
inner side of the substrate so as to make the designated space,
1700 is a first substrate holding means, 1710 is a second substrate
holding means, 1707 is a control valve on the side of exhausting
the composition from the space between the substrates and 1708 is a
control valve on the side of charging the composition into the
space between the substrates. FIG. 17(a) shows the first substrate,
FIG. 17(b) shows the space retaining means for keeping the
designated space between the outer side of the substrates, FIG.
17(c) shows the space retaining means for keeping the designated
space between the inner side of the substrates, FIG. 17(e) shows
the second substrate, FIG. 17(d) shows the plan view of the
situation in which the space retaining means are attached to the
first substrate holding means while the first substrate is
contacted to the first substrate holding means, FIG. 17(f) shows a
plan view of the situation in which the second substrate is
attached to the state shown by FIG. 17(d), and FIG. 17(g) is a
cross section of the state in which the second substrate holding
means is attached to the state shown by FIG. 17(f) and the
substrate holding means each holding the substrate are piled by
pressure.
[0158] The space retaining means 1750 used here is a member through
which the holographic recording layer forming composition can be
exhausted or charged from or into the space between the substrates,
in concrete, the space retaining means having the portion through
which the composition can be charged and exhausted as shown in
FIGS. 18(d) and 18(e) are usable. The space retaining means 1760 is
a member capable of keeping the space so as to have the designated
interval, in concrete, the parts shown by FIG. 9(d) or FIG. 9(e)
are usable from which the composition cannot be leaked. However,
the space retaining means such as those shown by FIG. 9(c) or 9(d)
may be used according to the position of the injection and the
ejection portions of the recording layer forming composition. In
such the case, at least one of the first and second substrates
having the composition charging portion for injecting the recording
layer forming composition into the space between the first and
second substrates and the composition exhausting portion for
exhausting the composition from the space between the substrates
may be optionally usable according to necessity.
[0159] FIGS. 18(a) through 18(j) show the method for charging the
holographic recording layer forming composition into the designated
space between the substrates formed by the space retaining means
and the substrate holding means shown by FIGS. 17(a) through 17(g).
In FIG. 18(a) through 18(j), 1800 is a first substrate holding
means, 1810 is a second substrate holding means, 1807 is a control
valve on the side of exhausting the composition from the space
between the substrates, and 1808 is a control valve on the side of
charging the composition into the space between the substrates,
1820 is a first substrate, 1830 is a second substrate, 1850 is an
outer side space retaining means, 1860 is an inner side space
retaining means, 1840 is a holographic recording layer forming
composition to be charged. FIGS. 18(a) and 18(b) show the situation
before charging the holographic recording layer forming composition
between the substrate, FIGS. 18(c) and 18(d) show the situation in
which the charging of the holographic recording layer forming
composition is started by applying pressure to the composition,
FIGS. 18(e) and 18(f) show the situation of the composition is
charged until half of the substrate, FIGS. 18(g) and 18(h) show the
state in which the space between the substrates is filled up by the
composition, and FIGS. 18(i) and 18(j) are the scheme of the
situation in which the valve on the charging side is closed for
stopping the supply of the composition. FIGS. 18(a), 18(c), 18(e),
18(g) and 18(i) are each a scheme of the horizontal cross section
through the second substrate of the substrate holding means piled
by pressure, and FIGS. 18(b), 18(d), 18(f), 18(h) and 18(j) are
each a scheme of the vertical cross section of the substrate
holding means piled by pressure for convenience of the
explanation.
[0160] The recording media can be produced which have each a
uniform whole thickness at any portion thereof and the uniform
designated thickness of the recording layer and the fluctuation of
the layer thickness between the individual recording media can be
reduced since the substrate holding means commonly can be used when
the recording layer forming composition is charged between the
substrates by applying the recording layer forming composition
charging means shown by FIGS. 18(a) through 18(j).
[0161] In the foregoing FIGS. 15(a) through 15(h) and FIGS. 18(a)
through 18(j), the method for charging the holographic recording
layer forming compound is described as the recording layer forming
compound charging method by which the compound is charged while
applying pressure. In such the case, the portion for charging the
composition into the space between the substrates is preferably
positioned at a position lower than that of the portion for
exhausting the composition from the space between the substrates to
prevent defects caused by mixing of bubbles into the charged
recording layer. Moreover, a method for charging the recording
layer forming composition between the first substrate and the
second substrate by sucking can be applied for the method shown by
the drawings. In such the case, the holographic recording layer
forming composition is charged by sucking through the portion for
exhausting the composition from the space between the substrates.
The pressure to be applied on the occasion of the ejection charging
is usually from 111 kPa to 20200 kPa, and preferably from 121 kPa
to 10100 kPa, even though the pressure cannot be simply decided
since the suitable pressure is changed according to the physical
property of the recording layer forming composition. In the suction
charging method, the reducing degree of pressure is preferably from
0.01 kPa from 60 kPa, and more preferably from 0.05 kPa to 40
kPa.
[0162] The space forming process and the recording layer forming
composition providing process is preferably performed under a
reduced pressure to inhibit the mixing of the bubbles in the
holographic recording layer as small as possible. The reduced
pressure is preferably from 0.05 kPa to 80 kPa, and more preferably
from 0.1 kPa to 50 kPa, compared with the ordinary atmosphere
pressure. Moreover, according to the kind of the holographic
recording layer forming composition, the reduced pressure
atmosphere prepared by reducing pressure after replacement of the
air by inactive gas such as nitrogen or argon or the dried air is
suitably utilized.
[0163] When the substrate holding means shown by FIGS. 16(a)
through 16(c) are used, one holographic recording medium only
produced at once. However, plural recording media can be
simultaneously produced by the use of the substrate holding means
shown by FIGS. 19(a) and 19(b).
[0164] In FIGS. 19(a) and 19(b), (a) is a first substrate holding
means and (b) is a second substrate holding means.
[0165] In the drawings, 1970 and 1971 are each a course of the
injection of the holographic recording layer forming composition,
1904 and 1914 are each a substrate holding means for holding each
of the substrate, 1990 and 1991 are each a course of the recording
layer forming composition connecting each of the substrate holding
portions, 1980 and 1981 are each a course for exhausting the
holographic recording layer forming composition from the substrate
holding means, 1907 is a control valve provided in the substrate
holding means on the side of exhausting the composition from the
space between the substrates each held by each the substrate
holding means, and 1908 is a control valve provided in the
substrate holding means on the side of charging the composition to
the space between the substrates each held by each the substrate
holding portion. In all of the foregoing production methods in the
first and second embodiments, the substrate and the substrate
holding means are each constituted by different matter. However,
the substrate having the function of the substrate holding means
can be suitably used according to the kind of the substrate to be
used for the holographic recording medium. As the example of the
substrate having such the portion, one shown by FIGS. 20(a) through
20(c) can be cited.
[0166] In FIGS. 20(a) through 20(c), 2000 is a second substrate,
2001 is a recording layer forming composition charging portion,
2002 and 2003 are each a space retaining means for the first
substrate, 2004 is a projection for removing level difference
between the first substrate, 2005 and 2007 are each a portion for
exhausting the recording layer forming composition from the space
between the substrates, 2006 and 2008 are each a portion for
charging the composition into the space between the substrates and
the 2010 is the first substrate. FIG. 20(a) is a plan view of the
second substrate, FIG. 20(b) is a plan view of the first substrate,
and FIG. 20(c) is a scheme of the vertical cross section of the
state in which the first substrate and the second substrate are
piled by pressure.
[0167] When the designated space is made between the substrates by
the foregoing space retaining means or by the space retaining
portion provided to the substrate in the second embodiment of the
invention, it is suitably applied in the invention that the space
retaining means and the substrate or the substrates are pasted with
together for retaining the designated space.
[0168] An example of the method using the space retaining means
firmly fixed with the second substrate is explained referring FIGS.
21(a), 21(b), 22 and 23.
[0169] FIG. 21(a) shows the space retaining means. In FIG. 21(a),
2150 is an outer space retaining means, 2151 is a recording layer
forming composition charging portion, and 2152 is a composition
exhausting portion. FIG. 21(b) shows a second substrate 2120 which
is pasted with a first substrate, not shown in the drawing, through
the outer space retaining means 2150 and an inner space retaining
means 2160 for previously reducing unevenness the thickness of the
recording layer to be charged into the recording medium and
unevenness of the whole thickness of the recording medium. In FIG.
22, plural recording media before charging of the recording layer
forming composition 2200 shown in FIG. 21(b) are connected in
series by connecting pipes 2392 for charging the recording layer
forming composition into each of the media before charging of the
recording composition. FIG. 23 shows an example of arrangement for
charging the recording layer forming composition into the recording
media before charging of the composition connected in series by the
connecting pipes 2392. When an injection charging method is used,
pressure is applied from the pipe at left side of FIG. 23 so that
the recording layer forming composition is charged into the space
between the substrates and the pressure applying is continued until
the composition is overflowed from the composition exhausting
portion of the right side recording medium. Thus the recording
layer can be charged into all the recording media. Besides, a
suction charging method is used, the air is sucked from the
exhausting portion of the right side recording media and the
recording layer forming composition is inhaled through the pipe at
the left side so that the composition is charged between the
substrates. The sucking is continued until the composition is
exhausted from the exhausting portion of the right side recording
medium. Thus the recording layer can be charged into all the
recording media.
[0170] The recording media can be produced which has each a uniform
whole thickness at any portion thereof and the uniform designated
thickness of the recording layer by charging the recording layer
forming composition in to the space between the substrates having
such the space retaining means as shown in FIG. 23. Moreover, the
fluctuation of the layer thickness between the individual recording
media can be reduced by the use of the standardized space retaining
means.
[0171] Next, producing processes commonly applied for the
production methods of the first and the second embodiments of the
invention are described in detail below.
[0172] Any bubble removing method can be applied without any
limitation as long as the method can remove the air contained in
the holographic recording layer charged between the first and the
second substrates by deaeration while the designated space is
retained. As such the bubble removing method, the following methods
such as a pressure reducing method by which the holographic
recording layer charged between the first and second substrates is
stand for a moment under a reduced pressure, and a method by which
the air contained in the recording layer being between the
substrates is driven out of the substrate by irradiating ultrasonic
vibration having a specific frequency oscillated by an ultrasonic
wave oscillator can be optionally applied.
[0173] FIGS. 224(a) through 24(e) show an example of the use of the
ultrasonic wave oscillator as the bubble removing means. In FIG.
24(a), 2403 shows the state in which the recording layer forming
composition is charged between the substrates shown by FIG. 3(f) or
3(j), 2404 in FIG. 24(b) shows the state in which the recording
layer forming composition is charged between the substrates shown
by FIG. 4(k), FIG. 24(c) shows the state in which the recording
layer forming composition is charged between the substrates shown
by the foregoing FIG. 11(h), FIG. 24(d) shows the state in which
the recording layer forming composition is charged between the
substrates shown by FIG. 15(h), and FIG. 24(e) the state in which
the recording layer forming composition is charged between the
substrates shown by FIG. 18(j). In the drawings, 2401, 2402, 2403,
2404 and 2405 are each the ultrasonic vibrator.
[0174] The fine spaces and the gas dissolved in the recording layer
forming composition can be driven out from the substrate by
applying the vibration with the specific frequency to the state of
the composition is filled between the substrates. The hardening
process to be applied after the bubble removing process by heating
or exposing to light having a wavelength different from that of
light for holographic recording are performed for hardening some
degree the recording layer forming composition according to the
invention to make the composition to difficultly fluidable. The
temperature for the hardening by heat is usually from 20.degree. C.
to 180.degree. C., and preferably from 25.degree. C. to 150.degree.
C. The preferable time for heating treatment at a temperature of
100.degree. C. or more is from 0.1 seconds to 2 hours, that at a
temperature of from 50.degree. C. to less than 100.degree. C. is
from 1 minute to 1 week, and that at a temperature of less than
50.degree. C. is from 1 hour to 1 month. For heating process, the
methods such as a method of heating by in an oven while keeping the
designated space, and a method, when the substrate holding means,
of heating the substrate holding means by a heater built in near
the face of the substrate holding means to be contacted to the
substrate can be optionally applied. When the substrate holding
means is not used, for example, in the case of that the recording
medium is produced by the use of the space retaining means only
such as that shown in FIG. 23, the hardening can be performed by
the method shown by FIGS. 36(a) through 36(d). As is shown in FIGS.
36(a) and 36(b), heating treatment can be performed by contacting
the heating block 3610 having heating members 3611 and 3612. In the
drawings, 3600 is the part of the substrates filled by the
recording layer, 3620 and 3621 are the pipes connecting between the
portions of the substrates each filled by the recording layer.
[0175] When the recording layer is hardened by irradiation of light
different in the wavelength from light to be used for holographic
recording, the wavelength of the light is preferably longer 50 nm
or more, and more preferably longer 100 .mu.m, than that of the
laser light for holographic recording exposure. The hardening
method of wholly and uniformly irradiating the recording medium by
the light is shown in FIGS. 35(a) through 35(e). In the case of
that the hardening is carried out by light, when the substrate
holding means transparent to the wavelength of the light is used,
the recording medium can be wholly irradiated and hardened by the
light by the method such as that shown by FIG. 35(a) with respect
to the medium prepared according to FIG. 4(k), that shown by FIG.
35(b) with respect to the medium prepared according to FIG. 18(j),
and that shown by FIG. 35(d) with respect to the medium prepared
according to FIG. 23 using the substrate holding means.
[0176] Removal of the holographic recording layer forming
composition forced off from the substrate after hardening by the
foregoing hardening treatment for making the recording layer to
non-fluidable is a process to remove the excessive part of the
medium so as to remove the hindrance for practical use. As the
removal method, methods usually applied in various field such as
methods by wiping out, cutting out and shaving the excessive part
can be optionally applied as long as the properties of as the
holographic recording medium is not degraded by the treatment. Some
examples of the methods for removing the holographic recording
layer forming composition forced off from the substrate are shown
in FIGS. 25(a) through 25(i).
[0177] FIG. 25(a) shows the recording medium treated until the
hardening treatment in the production method of FIGS. 4(a) through
4(k), the recoding medium has the recording layer forming
composition forced off from the outer side 2511 of the first
substrate 2510 and that forced off to inner side 2512. FIG. 25(b)
is a scheme of the process for cutting off the excessive portion of
the composition by irradiating laser light to the edge of the
substrate, and the FIG. 25(c) is a scheme of the recording medium
after removing the excessive part by the removing process shown by
FIG. 25(c). FIG. 25(d) shows the recording medium treated until the
hardening treatment in the production method of FIGS. 11(a) through
11(h), the recoding medium has the recording layer forming
composition forced off 2531 and 2532 from the second substrate
2530. The recording medium such as that shown by FIG. 25(f) can be
prepared by shaving the forced off portion by a claw like tool 2540
for shaving off the excessive portion. FIG. 25(g) show a medium
treated until the hardening process which has a forced off part
2251 from the first substrate 2550. The recording medium shown by
FIG. 25(i) can be prepared by removing the forced off part by a
sharp cutting tool 2560 capable of cutting the excessive part as
shown by FIG. 25(h).
[0178] The removing method shown by FIGS. 25(a) through 25(i) is a
method for removing the excessive part of the recording medium one
by one. FIGS. 26(a) and 26(b) show a excessive part removing method
by which plural media can be simultaneously treated. For example,
the plural recording media 2610 produced by the producing method
shown by FIGS. 18(a) through 18(j) and treated until hardening
process are fixed to a rotatable shaft 2612 by a fixing tool 2613
as shown in FIG. 26(a). The recording media 2610 each has the
portion 2611 through which the recording layer forming composition
is charged or exhausted. The media fixed to the rotatable shaft are
touched to a grinder 2615 having a grinding agent on the surface
thereof to remove the excessive part by grinding. Thus the
excessive parts of the plural recording media can be removed at
once. In the method shown by FIG. 26(b), plural recording media
2620 produced by the producing method shown by FIGS. 15(a) through
15(h) and treated until hardening process are fixed to a rotatable
shaft 2622 by a fixing tool 2623 through a cushion 2624 for
protecting the recording media 2620. A visible portion of the
recording layer 2621 is on the medium. The media fixed to the shaft
are touched to a grinder having a grinding agent on the surface
thereof and rotated by a shaft 2626 to remove the excessive part of
the substrate and/or recording layer by grinding. Thus plural media
having the trued up edges can be produced at once.
[0179] The sealing process to be applied at the last step of the
production for sealing the portion, where the holographic recording
layer is bare, is described referring some examples.
[0180] FIGS. 27(a) through 27(e) show an example of the tool for
sealing the bare portion of the recording layer. The sealing tool
2720 shown by FIG. 27(a) is a rotation type tool having a face 2721
for supplying a sealing material to the surface and a rotatable
shaft, and the tool 2730 shown by FIG. 27(b) is a rotation type
tool having a shaft the same as that in the tool shown by FIG.
26(a), grooves fitted to the thickness of the recording medium and
a face 2731 for supplying a sealing agent. The sealing tool 2740
shown by FIG. 27(c) is an extrusion type sealing tool having a
nozzle 2741 extruding the sealing agent. Moreover, the bare portion
of the holographic recording layer can be sealed by transferring a
sealing layer itself. For example, as is shown in FIG. 27(d),
sealing layers 2751 and 2752 are provided to the sealing layer
transferring means. The sealing tool shown by FIG. 27(e) is a
transfer ribbon type sealing tool having a supplying roller 2763 of
a sealing layer transfer ribbon 2760, a wind up roller 2762 and a
platen roller 2761 for pressing the transfer ribbon to the outer
edge of the recording medium.
[0181] Next, the concrete sealing method using the foregoing
sealing tool and the sealing material is described below referring
FIGS. 28(a) through 28(i).
[0182] A recording medium 2803 shown by FIG. 28(b) has bare areas
of the recording layer 2804 and 2805. For sealing the recording
medium, for example, an inner sealing member 2801 having a claw for
making the designated space between the first substrate and the
second substrate is put at the inner side of the recording medium
2803 to seal the inner side of the medium. On this occasion, an
adhesive agent may be coated on the substrate and the face to be
contacted to the holographic recording layer of the inner sealing
means 2801. Next, a method for sealing the bare area of holographic
recording layer 2805 at the outer side of the medium is described
below. FIG. 28(d) is an example of sealing by the use of the
rotation type tool 2820 such as that described in detail by FIG.
27(a). The outer edge of the recording medium can be sealed by
touching the sealing agent supplying face 2821 to the bare area of
the recording layer and synchronously rotating the recording medium
2803 and the rotation tool 2820. FIG. 28(e) shows an example of
sealing by the use of a rotation type tool 2830 such as that
described in detail by FIG. 27(b), in which the sealing agent
supplying surface 2831 is touched to the surface of the bare area
of the recording layer and the recording medium and the rotation
type tool 2830 are synchronously rotated. Thus the outer side of
the medium including a part of the outermost surface of the medium
can be uniformly sealed. FIG. 28(g) shows an example of sealing by
the use of the transfer ribbon type sealing tool such as that
described in detail by FIG. 27(e). A sealing layer transfer ribbon
2860 is pressed to the outer edge of the recording medium by a
platen roller 2861 at a portion between a supplying roller 2863 and
a wind up roller 2862, and the sealing layer transfer ribbon 2860
is synchronously wound up with the rotation of the recording medium
2803. Thus the outer edge of the recording medium is uniformly
sealed.
[0183] FIG. 28(f) shows an example of sealing by the use of the
extrusion type sealing tool such as that described in detail by
FIG. 27(c). In this method, a recording medium 2809, which has a
recording layer bare portion 2809 and is held by space retaining
means 2807 and 2808, is rotated to adhere thereon the sealing agent
extruded from a sealing agent extrusion nozzle 2841 of a sealing
tool 2840. Thus the sealing is carried out. In such the case, the
sealing agent either may be extruded only to the bare portion or to
all circumference edge of the recording medium 2806. FIGS. 28(h)
and 28(i) show an example of sealing by the use of a sealing layer
transfer means 2850 on which sealing layers 2851 and 2852 are
previously provided such as described in detail by FIG. 27(d). In
this case, a sealing layer transfer means 2850 is contacted to a
recording media 2810 and the sealing layer is only transferred by
pressure or heat and pressure onto the recording medium for sealing
the recording media which has portions of bare holographic
recording layer 2814 and 2813 and held by space retaining means
2812 and 2811. In the method shown by the drawings, the sealing
layer is transferred only to the portion to be sealed. However, the
sealing layer may be transferred to all the surface of the
recording medium including the portion of bare recording layer
thereon as long as the recording and reproduction property of the
recording medium is not influenced by the sealing layer.
The Third Embodiment of the Invention
[0184] FIGS. 29(a) through 29(e) show the structure of a recording
medium before charging of holographic recording layer forming
composition held in which first and second substrates are held by
space retaining means. FIG. 29(a) shows the first substrate, FIG.
29(b) shows an outer side space retaining means 2902 for retaining
the designated space between the outer side of the substrates,
which has a portion 2903 through which the recording layer forming
composition is injected, FIG. 29(c) shows an inner side space
retaining means 2904 for retaining the designated space between the
inside of the substrates, FIG. 29(d) shows a second substrate 2905,
and FIG. 29(e) show a plan view of a medium before charging of
composition which constituted by holding substrate space retaining
means and each substrates which are connected by a adhesive agent
so as to retain the designated space.
[0185] FIGS. 30(a) through 30(f) show an example of charging the
holographic recording layer forming composition into a recording
medium before charging of the composition. In drawings, 3000 is the
recording medium before charging of the composition, 3003 is a
portion through which the holographic recording layer forming
composition is injected, 3010 is a pressure reducible chamber, 3020
is a pressure controlling means for controlling the pressure, 3020
is the holographic recording layer forming composition, 3040 is a
composition supplying means for supplying the holographic recording
layer forming composition, 3050 is a pressure keeping valve for
keeping the pressure in the pressure reducible chamber, and 3060 is
the recording medium filled by the holographic recording layer
forming composition. At the beginning, as is shown by FIG. 30(a),
the pressure in the pressure reducible chamber 3010 is reduced by
sucking the gas in the chamber through the pressure controlling
means 3020 to wholly reduce the pressure in the recording medium
before the composition and in the entire chamber. Then the pressure
keeping valve is closed after some degree of the reduced pressure
is kept as shown by FIG. 30(b), and a recording layer forming
composition injecting portion 3003 is immersed into the composition
stored in a composition storing tank and the pressure keeping valve
is open to restore the pressure in the chamber 3010 to the ordinary
pressure while the recording layer forming composition injection
portion is immersed into the composition as shown in FIG. 30(d).
The holographic recording layer forming composition 3030 can be
charged into the empty space in the recording medium 3000 by
restoring the pressure to the ordinary pressure such as shown by
FIG. 30(e). Finally, the recording medium 3060 filled by the
holographic recording layer forming composition 3030 is turned so
that the recording layer forming composition injecting portion of
the recording medium is brought at the upper position as shown by
FIG. 30(f). Thus the recording media filled by the recording layer
forming composition can be prepared, from which the recording layer
forming composition is not escaped even if the recording medium is
stand under the ordinary pressure.
[0186] As above-described, the recording media having each a
uniform whole thickness at any portion thereof and the uniform
designated thickness of the recording layer by charging the
recording layer forming composition into the empty space between
the substrates by using the pressure controllable recording layer
forming composition charging means as shown in FIGS. 30(a) through
30(f). Moreover, the fluctuation of the layer thickness between the
individual recording media can be reduced by the use of the
standardized space retaining means.
[0187] A bubble removing process for removing the air layer
included in the holographic recording layer forming composition
being between the first and second substrates by deaeration, and a
hardening process by heating or irradiation of light having a
wavelength different from that of light to be used for holographic
recording exposure to be performed after the bubble removing
process, to be applied in the fifth embodiment may be optionally
selected from those described in detail in the first through fourth
embodiments. For example, the light hardening treatment shown in
FIG. 35(e) and the heat hardening treatment shown in FIGS. 36(d)
and 36(d) can be applied. In FIG. 36(c), 3600 is a recording medium
filled by the recording layer forming composition, and 3630 and
3640 are heating blocks and 3631 and 3641 are heating means.
[0188] A means for removing the holographic recording layer forming
composition forced off from the substrate to be applied after the
hardening treatment, a means for cutting the medium into designated
sized after the hardening treatment, and a means for sealing the
bare portion of the holographic recording layer are also optionally
selected from those described in detail in the first through fourth
embodiments.
[0189] Next, an example of the production method using the suction
recording layer forming composition charging method for charging
the composition is described below referring the drawings.
[0190] FIGS. 31(a) through 31(e) show the constitution of an empty
recording medium in which the recording layer forming composition
is not charged yet, in which first and second substrates are each
held by a space retaining means. FIG. 31(a) shows the first
substrate 3101, FIG. 31(b) shows an outer side space retaining
means 3102 for keeping the space between the outer side of the
substrates which has a portion 3103 through which the recording
layer forming composition is injected, FIG. 31(c) shows an inner
side space retaining means 3104 for retaining the space between the
inner side of the substrates, FIG. 31(d) shows a second substrate,
and FIG. 31(e) shows a plan view of empty recording medium 2900
which is constituted by the space retaining means and the
substrates each held so as to make the designated space between
them.
[0191] FIGS. 32(a) through 32(c) show a substrate holding means.
Among them, FIG. 32(a) shows a first substrate, FIG. 32(c) shows a
second substrate, and FIG. 32(c) shows a cross section of a piled
state of the first substrate and the second substrate. In FIGS.
32(a) through 32(c), 3210 is the first substrate holding means,
3211 is a face to be contacted to the second substrate, 3220 is a
second substrate holding means, 3221 is a face to be contacted to
the first substrate, 3212 and 3222 are each a face for holding each
of the substrates, 3213 and 3223 are each a suction hole for
contacting the substrate by vacuum, 3214 and 3224 are each a
portion through which the holographic recording layer forming
composition is injected in to the space between the substrates, and
3215 is a controlling valve for controlling the composition on the
occasion of the injection of the composition into the space between
the substrate of the empty recording medium.
[0192] FIGS. 33(a) and 33(b) show the state of the empty recording
medium shown by FIGS. 31(a) through 31(e) is set by using the
substrate holding means shown by FIG. 32(a) through 32(c). FIG.
33(a) shows a scheme of horizontal cross section of the substrate
holding means in a state of piled by pressure seen through the
second substrate and FIG. 33(b) shows a scheme of vertical cross
section of the substrate holding means in a state piled by
pressure. In the drawings, 3300 is an empty recording medium before
charging of the recording layer forming composition, 3303 is a
portion through which the recording layer forming composition is
injected, 3314 is a portion through which the recording layer
forming composition is injected into the empty recording medium
held in the substrate holding means, 3315 is a controlling valve
for injecting the composition into the empty recording medium, 3310
is a first substrate holding means, and 3320 is a second substrate
holding means.
[0193] FIGS. 34(a) through 34(f) show an example of method for
charging the holographic recording layer forming composition into
an empty recording medium held by the substrate holding means shown
by FIGS. 33(a) and 33(b). In the drawings, 3400 is an empty
recording medium, 3430 is a composition supplying means in which
the holographic recording layer forming composition is charged,
3440 is a supplying control valve for controlling the composition
supplied from the composition supplying means, 3450 is a pressure
reducing control valve for controlling the reducing degree of the
pressure, 3460 and 3462 are each a reducing pressure controlling
and composition supplying pipe, 3461 is a reduced pressure
controlling pipe, 3470 is the recording medium filled by the
holographic recording layer forming composition. The supplying
control valve 3440 and the reduced pressure control valve 3450 are
each a three-way valve. Firstly, the pressure is reduced by sucking
gas through the reducing pressure control pipe as shown by FIG.
34(a). In this occasion, the pressure reduced places is interior of
the empty recording medium 3400, pipes 3462 and 3460, the three-way
supplying control valve 3440, and the three-way pressure control
valve 3450. The three openings of the supplying control valve 3440
are each opened to the pipe 3460, 3462 and pressure reducing pipe
3461, respectively, and only one of the three way reducing pressure
control valve 3450 is opened to the pipe 3460. Then the openings of
the three-way valve 3450 are moved so as to only connect the pipe
3462 to the reduced pressure control pipe 3461 as shown by FIG.
34(b), and to fix the pressure reduced state in the pipe 3460 and
the supplying control valve 3440. Thereafter, the openings of the
three-way valve 3440 are moved so as to only connect the
composition supplying means 3430 to the pipe 3460 as shown by FIG.
34(c), and the recording layer forming composition is charged into
the supplying control valve 3440 and the pipe 3460. Then the
openings of the three-way valve are moved so as to close the
reduced pressure control pipe 3461 and connect the pipe 3460 to the
pipe 3462 as shown by FIG. 34(d), and the recording layer forming
composition is supplied to the pipe 3462 from the pipe 3461 through
the reduced pressure control valve. Thus the recording layer
forming composition can be charged into the empty recording medium
in the reduced pressure state to prepare the recording media 3470
filled as shown by FIG. 34(e). Finally, the pressure is restored to
the ordinary pressure by stopping the suction and the three
openings of the reduced pressure control valve 3450 are moved so
that the openings are each connected to pipe 3460, pipe 3462 and
the reduced pressure control pipe 3461. Then the pipe 3462 is
removed. Thus the holographic recording layer forming composition
can be charged to the recording medium held by the substrate
holding means.
[0194] The recording media can be produced which has each a uniform
whole thickness at any portion thereof and the uniform designated
thickness of the recording layer by charging the recording layer
forming composition into the empty space between the substrates by
using the pressure controllable recording layer forming composition
charging means as shown in FIGS. 34(a) through 34(f). Moreover, the
fluctuation of the layer thickness between the individual recording
media can be reduced by the use of the standardized space retaining
means.
[0195] A bubble removing process for removing by deaeration the air
layer included in the holographic recording layer forming
composition charged between the first and second substrates, and a
hardening process by heating or irradiation of light having a
wavelength different from that of light to be used for holographic
recording exposure to be performed after the bubble removing
process, to be applied in the fifth embodiment may be optionally
selected from those described in detail in the first through fourth
embodiments. Among them, the light hardening can be performed as
shown in FIG. 35(c) as the hardening method. The bubble removing
and the hardening may be performed either in the state in which the
pipe is removed as shown by FIG. 34(f) or the pipe is not removed.
A means for removing the holographic recording layer forming
composition forced off from the substrate to be applied after the
hardening treatment, a means for cutting the medium to designated
sized after the hardening treatment, and a means for sealing the
bare portion of the holographic recording layer are also optionally
selected from those described in detail in the first through fourth
embodiments.
[0196] As the holographic recording layer forming composition to be
used in the production of the holographic recording medium may be
optionally selected from those described in, for example, JP O.P.I.
Publication Nos. 5-107999, 6-301322, 8-101500, 1-101501 and
8-160842, U.S. Pat. Nos. 6,103,454 and 6,482,551, U.S. Patent
Application Publication No. 2003/44690, and International Patent
Nos. 2003/23519 and 2003/23520.
[0197] Any transparent material which does not occur any expansion
and contraction under using temperature condition and is inactive
to the holographic recording layer forming composition can be used
as the first and the second substrates without any limitation.
Examples of such the material include glass such as quartz glass,
sodium glass, potassium glass, lead crystal glass, borosilicate
glass, aluminosilicate glass, titanium crystal glass, and
crystallized glass, and various kind of resin such as
polycarbonate, polyacetal, poly(ether-ether-ketone), polysulfone,
polyethersulfone, polyimide such as poly(imide-amide), and
polyetherimide, polyamide, and a ring opening polymer of cyclic
polyolefin.
[0198] The first substrate to be arranged at the incidence side of
the information recording light and the reference light is
preferably made by glass from the viewpoint of the thickness
variation depending on the temperature and the moisture on the
occasion of the holographic recording exposure and the
transmittance of light from the light source for the holographic
recording. Although the material of the second substrate is also
preferable glass, the substrate may be made from resin, even though
which is not a material inhibited in the expansion and contraction
and the thickness variation, when the equipment for reading the
holographic recorded information by a CCD has a focus compensation
mechanism.
[0199] The transmittance of the first substrate at the incidence
side of the information recording light and the reference light is
preferably not less than 70%, and more preferably not less than
80%, since the loss of the light to be attained to the holographic
recording layer. It is preferable for raising the transmittance as
high as possible that the surface of the first substrate opposite
to the surface facing to the holographic recording layer is
subjected to a reflection inhibiting treatment. There is no
limitation on the material to be used for the reflection inhibiting
treatment as long as the refractive index thereof is lower than
that of the material of the first substrate. For example, a metal
fluoride such as AlF.sub.3, MgF.sub.2, AlF.sub.3.MgF.sub.2,
CaF.sub.2, and an organic fluorine compound, for example, a
homopolymer, copolymer graft polymer and block polymer each
containing a fluorine atom such as vinylidene fluoride and
perfluoroethylene, and a modified polymer decorated by a
fluorine-containing functional group are preferred since these
compounds each have a refractive index lower than that of the
foregoing substrate.
[0200] As the method for providing the layer of the
fluorine-containing compound, known methods such as a sol-gel
method, a vacuum evaporation method, a spattering method, a CVD
method and a coating method, and those described in JP O.P.I.
Publication Nos. 7-27902, 2001-123264 and 2001-264509 are
optionally usable, even though the method cannot be decided
unconditionally since the condition is varied depending on the kind
of the substrate or the fluorine compounds.
[0201] The thickness of the reflection inhibiting layer is usually
from 0.001 to 20 .mu.m, preferably from 0.005 to 10 .mu.m, even
though the thickness cannot be decided unconditionally since the
condition is varied depending on the surface treatment or the
material of the substrate.
[0202] In the recording media to be used in holographic
recording-reproducing equipment such as those disclosed in JP
O.P.I. Publication No. 2002-123949 and International Patent
Publication 99/57719, it is preferable that the reflective layer is
provided on the surface facing to the holographic recording layer
or the opposite surface of second substrate. When such the
reflective layer is provided, the layer has a reflectance of not
less than 70%, and more preferably not less than 80%, to the
wavelength of light to be reflected.
[0203] There is no limitation on the reflective layer as long as
the desired reflectance can be obtained, and usually a metal thin
layer may be provided on the surface of the substrate. For forming
such the reflective layer, a single crystal or polycrystal of the
metal can be provided by a known method such as an ion plating
method and a spattering method in a form of the thin layer. The
metal thin layer can be formed by one or more kind of metal such as
aluminum, zinc, antimony, indium, selenium, tin, tantalum,
chromium, lead, gold, silver, platinum, nickel, niobium, germanium,
silicon, molybdenum, manganese, tungsten, and palladium. The
thickness of the metal thin layer is usually from 1 to 3000 nm, and
preferably from 5 to 2000 nm even though the thickness is not
limited as long as the desired reflectance can be obtained.
[0204] On the other hand, with respect to the holographic recording
medium, a high memory capacity recording medium can be prepared by
making the thickness of the recording layer as thick as possible.
However, in the invention, considering the using environmental
condition and the reading error, the thickness of the recording
layer is preferably satisfies the relation of
0.15.ltoreq.Dh/(D1+D2).ltoreq.2.0, wherein D1 is the thickness of
the first substrate, D2 is the thickness of the second substrate
and Dh is the thickness of the holographic recording layer.
[0205] In the case of 0.15.ltoreq.Dh/(D1+D2), the thickness of the
holographic recording layer cannot be increased, when the thickness
of the recording layer is increased, the whole thickness of the
recording media is made thicker since the increasing of the
thickness of the substrate is necessary. Such the recording medium
is not preferred since the weight of the medium is large and
excessive loading to the driving system of the recording and
reading equipment tens to occur. Besides, in the case of
Dh/(D1+D2).ltoreq.2.0, the thickness of the recording medium can be
reduced while maintaining the thickness of the recording layer. In
such the case, however, the thickness of the recording layer is
become too thick concerning in regard to the thickness of the
substrate. Such the medium is not preferred since the precision of
the surface and the unevenness of the thickness of the recording
medium under the using environments tend to be degraded and the
variation of the recording layer thickness and the running off of
the first substrate from the second substrate tend to be caused by
the application of accidental force.
[0206] Moreover, the thickness of the first substrate and that of
the second substrate preferably have the relation of D1.ltoreq.D2
from the view point of the energy loss of the holographic exposure
light, and the ratio of the thickness D1 to that of D2 is
preferably within the range of 0.20.ltoreq.D1/D2.ltoreq.1.00 for
keeping the flatness of the recording medium.
[0207] The thickness of the holographic recording layer is
preferably from 200 .mu.m to 2.0 mm. When the thickness is less
than 200 .mu.m, a recording medium having high memory capacity
cannot be obtained. When the thickness is larger than 2.0 mm, the
degradation of the surface precision and the unevenness of the
thickness of the recording layer depending on the temperature of
the using condition tend to occur.
[0208] The shape of the medium is not limited as long as the shape
is suited to the holographic recording and reproducing equipment,
for example, disc-shaped one is preferred for using in equipment
such as that disclosed in U.S. Pat. No. 5,719,691 and JP O.P.I.
Publication No. 2002-123949, and card-shaped one is preferable for
the equipment described in International Patent Publication
99/57719.
EFFECT OF THE INVENTION
[0209] As above-described, the holographic recording medium in
which the whole thickness of the recording medium is uniform at any
portion thereof, the designated thickness of the holographic
recording layer and the quality fluctuation between the individual
media is inhibited, can be produced by the use of the space
retaining means for retaining the uniform space between the
substrate, the selection of the various methods for charging the
holographic recording layer forming composition, and the
application of hardening treatment for hardening the composition
while uniformly retaining the space between the substrates
according to the invention. Moreover, the recording media produced
by the method according to the invention show high reliability on
the occasion of the recording and the reproducing since the
recording media have little variation between the production lots
thereof, high uniformity of the recording layer thickness and high
surface precision. The production method of the holographic
recording media can be provided by the invention, by which
recording media with small deformation and small fluctuation of the
property are produced.
* * * * *