U.S. patent application number 12/078641 was filed with the patent office on 2010-11-11 for method for producing conductive film and light-sensitive material for conductive film production.
This patent application is currently assigned to FUJIFILM Corporation. Invention is credited to Akira Ichiki, Joh Kumura, Tadashi Kuriki, Tsukasa Tokunaga.
Application Number | 20100282505 12/078641 |
Document ID | / |
Family ID | 37899942 |
Filed Date | 2010-11-11 |
United States Patent
Application |
20100282505 |
Kind Code |
A1 |
Ichiki; Akira ; et
al. |
November 11, 2010 |
Method for producing conductive film and light-sensitive material
for conductive film production
Abstract
A method for producing a conductive film, which comprises:
exposing and developing a light-sensitive material comprising a
support and thereon an emulsion layer containing a silver salt
emulsion to form a metallic silver; and then subjecting the
light-sensitive material to a smoothing treatment (such as a
calender treatment).
Inventors: |
Ichiki; Akira;
(Minami-Ashigara-shi, JP) ; Kumura; Joh;
(Minami-Ashigara-shi, JP) ; Kuriki; Tadashi;
(Minami-Ashigara-shi, JP) ; Tokunaga; Tsukasa;
(Minami-Ashigara-shi, JP) |
Correspondence
Address: |
BUCHANAN, INGERSOLL & ROONEY PC
POST OFFICE BOX 1404
ALEXANDRIA
VA
22313-1404
US
|
Assignee: |
FUJIFILM Corporation
Minato-ku
JP
|
Family ID: |
37899942 |
Appl. No.: |
12/078641 |
Filed: |
April 2, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11666749 |
May 2, 2007 |
7749686 |
|
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PCT/JP2006/320030 |
Sep 29, 2006 |
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12078641 |
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Current U.S.
Class: |
174/388 ;
174/250; 174/257; 252/514; 430/311; 430/315 |
Current CPC
Class: |
H05K 2203/0278 20130101;
G03F 7/063 20130101; H05K 2203/0143 20130101; G03F 7/40 20130101;
H05K 3/106 20130101; H05K 9/0096 20130101; Y10T 428/1241
20150115 |
Class at
Publication: |
174/388 ;
430/311; 430/315; 252/514; 174/257; 174/250 |
International
Class: |
H05K 9/00 20060101
H05K009/00; G03F 7/20 20060101 G03F007/20; H01B 1/02 20060101
H01B001/02; H05K 1/09 20060101 H05K001/09; H05K 1/00 20060101
H05K001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 30, 2005 |
JP |
2005-288956 |
Claims
1. A method for producing a conductive film, which comprises:
exposing and developing a light-sensitive material comprising a
support and thereon an emulsion layer containing a silver salt
emulsion to form a metallic silver portion; and then subjecting the
light-sensitive material to a smoothing treatment which is
performed with a calender roll unit at a line pressure of 980 N/cm
(100 kgf/cm) or more.
2. The method according to claim 1, which comprises: exposing and
developing a light-sensitive material comprising a support and
thereon an emulsion layer containing a silver salt emulsion to form
a metallic silver portion and a light-transmitting portion; and
then subjecting the light-sensitive material to a smoothing
treatment.
3. The method according to claim 1, which comprises: exposing and
developing a light-sensitive material comprising a support and
thereon an emulsion layer containing a silver salt emulsion to form
a metallic silver portion and an insulating portion; and then
subjecting the light-sensitive material to a smoothing
treatment.
4. The method according to claim 1, wherein the metallic silver
portion after the smoothing treatment comprises a silver and a
non-conductive polymer, and wherein a volume ratio of Ag/the
non-conductive polymer is 2/1 or more.
5. The method according to claim 1, wherein the metallic silver
portion after the smoothing treatment comprises a silver and a
non-conductive polymer, and wherein a volume ratio of Ag/the
non-conductive polymer is 3/1 or more.
6. The method according to claim 1, wherein 50% or more of a volume
of the non-conductive polymer is occupied by gelatin.
7. The method according to claim 1, which further comprises:
dipping the light-sensitive material in an aqueous solution of a
reducing agent between after the developing treatment and to the
smoothing treatment.
8. (canceled)
9. (canceled)
10. The method according to claim 1, wherein the smoothing
treatment with the calender roll unit is performed at a line
pressure of 1960 N/cm (200 kgf!cm) or more.
11. The method according to claim 1, wherein the smoothing
treatment with the calender roll unit is performed at a line
pressure of 2940 N/cm (300 kgf/cm) or more.
12. The method according to claim 1, wherein a volume ratio of Ag/a
binder in the emulsion layer is 1/2 or more.
13. The method according to claim 1, wherein a volume ratio of Ag/a
binder in the emulsion layer is 1/1 or more.
14. The method according to claim 1, wherein the support has
flexibility.
15. The method according to claim 1, wherein the conductive film
has electromagnetic wave-shielding properties.
16. A conductive film obtained by a production method according to
claim 1.
17. The conductive film according to claim 16, which comprises a
support and thereon a metal wiring pattern containing a silver at a
density of 8.0 g/cm3 to 10.5 g/cm3.
18. The conductive film according to claim 17, wherein a thickness
of the metal wiring pattern is from 0.5.about.tm to 5 pm.
19. The conductive film according to claim 16, which is an
electromagnetic wave-shielding film.
20. The conductive film according to claim 16, which is a printed
wiring board.
21. A conductive film, which comprises a support and thereon a
metal wiring pattern, wherein the metal wiring pattern is subjected
to a smoothing treatment which is performed with a calender roll
unit at a line pressure of 980 N/cm (100 kgf/cm) or more.
22. The conductive film according to claim 21, wherein the metal
wiring pattern contains a silver at a density of 8.0 g/cm3 to 10.5
g/cm3.
23. The conductive film according to claim 21, wherein a thickness
of the metal wiring pattern is from 0.5 pm to 5 pm.
24. The conductive film according to claim 21, wherein a line width
of the metal wiring pattern is from 0.1 pm to less than 18
25. The method according to claim 1, wherein the smoothing
treatment with the calender roll unit is performed at a line
pressure of 6,860 N/cm (700 kgf/cm) or less.
26. The method according to claim 25, which further comprises:
dipping the light-sensitive material in an aqueous solution of a
reducing agent between after the developing treatment and to the
smoothing treatment.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This is a Continuation-In-Part application which claims
priority under 35 U.S.C. .sctn.120 to pending application Ser. No.
11/666,749 filed in the United States on May 2, 2007; the entire
content of which is hereby incorporated by reference.
TECHNICAL FIELD
[0002] The present invention relates to a method for producing a
conductive film such as an electromagnetic wave-shielding film
which shields electromagnetic waves generated from front faces of
displays such as a CRT (cathode ray tube), a PDP (plasma display
panel), a liquid crystal display, an EL (electroluminescence)
display and a FED (field emission display), microwave ovens,
electronic equipments, printed wiring boards and the like and has
translucency, and a silver salt light-sensitive material for
forming the conductive film.
[0003] Further, in addition to the above-mentioned applications,
the invention also relates to a conductive film used for printed
boards and the like, and a production method thereof
BACKGROUND ART
[0004] In recent years, electromagnetic interferences (EMI) have
rapidly increased with an increase in utilization of various
electric installations and electronics-applied equipments. It is
pointed out that EMI not only causes malfunctions and damages to
electronic or electric equipments, but also damages health of
operators of these apparatuses. It is therefore required to
suppress intensity of electromagnetic waves emitted from the
electronic or electric equipments within the range of standards or
regulations.
[0005] As a countermeasure for the above-mentioned EMI, it is
necessary to shield electromagnetic waves, and for that purpose, it
is self-evident that what is necessary is just to utilize the
property of metals of not transmitting the electromagnetic waves.
For example, there are adopted a method of using a metal body or a
highly conductive body as a casing, a method of inserting a metal
plate between circuit boards, a method of covering a cable with a
metal foil, and the like. However, an operator needs to recognize
characters and the like displayed on a screen of CRT or PDP, so
that a display is required to have transparency. Accordingly, the
above-mentioned methods have been unsuitable as a method for
shielding the electromagnetic waves, because all the
above-mentioned methods often provide an opaque front face of the
display.
[0006] In particular, PDP generates electromagnetic waves in a
large amount compared to CRT or the like, so that stronger
electromagnetic wave-shielding ability has been desired. The
electromagnetic wave-shielding ability can be conveniently
represented by the surface resistance value. For example, the
surface resistance value is required to be about 300 .OMEGA./sq or
less for a light-transmitting electromagnetic wave-shielding
material for CRT, whereas it is required to be 2.5 .OMEGA./sq or
less for a light-transmitting electromagnetic wave-shielding
material for PDP. In a household plasma television utilizing PDP,
it is highly required to be 1.5 .OMEGA./sq or less, and more
desirably, an extremely high conductivity of 0.1 .OMEGA./sq or less
is required.
[0007] Further, as for the required level of translucency, the
whole visible light transmittance is required to be about 70% or
more for CRT and 80% or more for PDP, and further higher
transparency has been desired.
[0008] In order to solve the above-mentioned problems, various
materials and methods for allowing electromagnetic wave-shielding
properties, conductivity and translucency to be compatible with one
another by utilizing metal meshes having apertures have hitherto
been proposed, as shown below.
[0009] (1) Silver Paste-Printed Mesh
[0010] For example, there has been disclosed a method of printing a
paste comprising a silver powder in network form to obtain a silver
mesh (for example, see JPA-2000-13088). The silver mesh obtained by
this method has the problem that the line width is thick to
decrease transmittance, because it is formed according to a
printing method. Further, the surface resistance value is high,
resulting in low electromagnetic wave-shielding ability. It is
therefore necessary to apply a plating treatment to the resulting
silver mesh, in order to increase electromagnetic wave-shielding
ability.
[0011] (2) Irregular Network Silver Mesh
[0012] For example, there have been disclosed an irregular minute
network silver mesh and a production method thereof (for example,
see JP-A-10-340629). However, this production method has the
problem that only a mesh as high as 10 .OMEGA./q in surface
resistance value (low in electromagnetic wave shielding ability) is
obtained. Further, there has been the problem that the haze is as
high as ten-odd percents or more to cause blurring of a display
image.
[0013] (3) Etching-Processed Copper Mesh Utilizing
Photolithography
[0014] There has been disclosed a method for forming a copper mesh
on a transparent substrate by subjecting a copper foil to etching
processing using photolithography (for example, see JP-A-10-41682).
This method has the advantage of being able to prepare a mesh
having a high aperture ratio (high transmittance), which can shield
even a strong electromagnetic wave emission, because it is possible
to microfabricate the mesh. However, there has been the problem
that a production process thereof includes extremely many steps,
through which the mesh must be produced.
[0015] Further, there has been the problem that the accomplished
mesh shows a copper foil color, not black, because of the use of
the copper foil, which causes a reduction in contrast of images in
display instruments. Furthermore, this mesh has the problem that
the width of intersectional points in a grid pattern is thicker
than that of straight-line portions, because it is produced by the
etching method, and improvement of this problem has been desired in
association with the problem of moire.
[0016] (4) Blackening of Metallic Conductive Layer
[0017] As a preferable method for blackening metallic conductive
layers, for example, a surface treatment method after blackening
treatment (for example JP-A-2006-191010) has been proposed.
However, the surfaces of conductive layers as formed by plating,
vapor deposition and the like are coarse as they are,
disadvantageously requiring the enlargement of the thickness of the
resulting blackening layers or subsequent additional surface
treatment as a treatment for preventing uneven gloss.
[0018] (5) Conductive Silver Forming Method Utilizing Silver
Salt
[0019] In the 1960s, there has been disclosed a method for forming
a thin film pattern of metallic silver having conductivity by a
silver salt diffusion transfer process in which silver is deposited
on physical development nuclei (for example, see
JP-B-42-23746).
[0020] However, it does not refer to the possibility that the
resulting conductive metallic silver thin film can shield
electromagnetic waves emitted from image display surfaces of
displays such as CRT and PDP without inhibiting the image
display.
[0021] Actually, according to this method, a silver thin film
having a surface resistance value of 10 .OMEGA./sq to 100
K.OMEGA./sq is obtained. However, this level of conductivity is
insufficient as applications for displays such as PDP. Further,
also in terms of high translucency, it is not sufficient. Thus,
translucency and conductivity can not be compatible with each
other.
[0022] Accordingly, even when the above-mentioned silver salt
diffusion transfer process is used as it is, it has been impossible
to obtain a light-transmitting electromagnetic wave-shielding
material which is excellent in light transmitting properties and
conductivity, and suitable for shielding electromagnetic waves from
image display surfaces of electronic display equipments.
[0023] The invention also relates to a production method of a
printed board (printed wiring board), so that the background art
thereof will be described bellow. Conventional production methods
are largely divided into two types: a three-layer flexible board in
which a copper foil is adhered onto an insulator film using an
adhesive and a desired wiring pattern is formed by a subtractive
method, and a two-layer flexible board in which a desired wiring
pattern is formed by a subtractive method or an additive method,
using a substrate having a ground metal layer directly provided on
the insulator film without using the adhesive.
[0024] Further, the printed boards are classified into a flexible
board and a rigid board, depending on the material used in an
insulating substrate. The flexible board is one in which the
insulating substrate is formed of a flexible material such as a
polyimide resin or a polyester resin. On the other hand, the rigid
board is one in which the insulating substrate is formed of a
material having high hardness, such as glass or an epoxy resin.
[0025] Then, the three-layer flexible board whose production method
is simple generally occupies the mainstream. However, with a recent
increase in density of electronic equipments, the wiring width in a
wiring board has also come to be required to have a narrow pitch.
In the case of the above-mentioned three-layer flexible board, a
method for forming a wiring portion by etching has been proposed
(for example, JP-A-2003-309336 and the like). However, according to
this method, so-called side etching in which a side face of the
wiring portion is etched occurs, so that the cross-sectional shape
of the wiring portion is liable to become a trapezoid widened
toward the bottom. Accordingly, when etching is performed until
electric insulation properties between the wiring portions are
secured, the wiring pitch width becomes excessively wide. There has
been therefore a limitation on narrowing the wiring pitch.
[0026] Further, the production process is complicated and complex,
which causes the problem of increased production cost, and the
etching process also has a problem with regard to environmental
issues for waste liquid treatment.
[0027] Then, the larger this widening of the wiring portion to the
bottom by the side etching is, the thicker the thickness of the
copper foil becomes. Accordingly, in order to decrease the widening
to narrow the pitch, it has been necessary to use a copper foil
having a thickness of 18 .mu.m in place of the copper foil having a
thickness of 35 .mu.m which has hitherto been conventionally used.
However, such a thin copper foil has low rigidity, so that handling
properties are poor. Accordingly, there has been the problem that
rigidity must be increased by laminating a reinforcing material
such as an aluminum carrier. Further, such lamination has also
raised the problem of increased variations in film thickness or
coating defects such as the occurrence of pinholes or cracks.
[0028] Accordingly, the thinner the thickness of the copper foil is
made in order to narrow the pitch of the wiring portion, the more
difficult the production of the wiring board becomes, resulting in
increased production cost. In particular, there have recently
increased demands to a wiring board having a narrow-pitch wiring
portion which can not be produced without using a copper foil
having a thickness of ten-odd micron meters or less, particularly
several micron meters, so that the increased production cost of the
three-layer flexible board has increasingly become a problem.
[0029] Then, the two-layer flexible board in which a copper coating
can be directly formed on the insulator film without applying the
adhesive has come to be noted. In the two-layer flexible board, the
ground metal layer is directly formed on the insulator film by dry
plating or wet plating without using the adhesive, and the copper
conductive layer is formed thereon by an electroplating method. It
has therefore the advantages that the thickness of the substrate
itself can be decreased, and moreover, that the thickness of the
copper conductive coating to be adhered can also be adjusted to any
thickness.
[0030] A forming method of the ground metal generally employed at
present in order to obtain the two-layer flexible board of this
kind is a dry plating method. There has been proposed a method of
adhering the ground metal layer onto the insulator film, and then,
further forming the copper coating thereon by dry plating (for
example, JP-A-8-139448 and JP-A-10-154863). However, usually, many
pinholes having a size of tens to hundreds of micron meters are
present in the coating obtained by the dry plating method. The
final thickness of the copper coating formed is from about 0.2 to
about 0.5 .mu.m, and exposed parts caused by pinholes frequently
occur in the two-layer flexible board. In order to prevent this, it
is necessary to repeat ground formation or to impart a catalyst.
Accordingly, a problem has arisen in terms of production cost.
DISCLOSURE OF THE INVENTION
[0031] As described above, the conventional electromagnetic
wave-shielding materials and methods for producing them each have
the problems. Above all, an electromagnetic wave-shielding plate
obtained by forming a mesh composed of a metal thin film on a
transparent glass or plastic substrate surface has extremely high
electromagnetic wave-shielding properties, and good light
transmitting properties are obtained, so that it has recently come
to be used as an electromagnetic wave-shielding material for a
display panel such as PDP.
[0032] However, reduction of the production cost has been strongly
desired because of its extremely high price. Further, high
lightness of images is required for a display, so that it has
required that the light transmittance is close to 100%, and that
the color of the mesh is black. However, when the proportion of the
open area ratio (portions not having fine lines constituting a
mesh) with respect to the total is increased in order to improve
light transmitting properties, conductivity is decreased to degrade
electromagnetic wave-shielding effect. It has therefore been
extremely difficult to simultaneously improve conductivity
(electromagnetic wave-shielding effect) and light transmitting
properties by conventional techniques.
[0033] The invention has been made in view of such a situation. An
object of the invention is to provide a conductive film in which a
metal portion has high conductivity and a nonmetal portion has
excellent translucency and/or insulating properties. More
specifically, an object of the invention is to provide a
light-transmitting electromagnetic wave-shielding film
simultaneously having high electromagnetic wave-shielding
properties and high translucency, and having a black mesh portion,
and to provide a method for producing a light-transmitting
electromagnetic wave-shielding film, in which the formation of a
fine line pattern is possible in a short process, and which can be
produced at low cost in large amounts. Another object of the
invention is to provide a light-transmitting electromagnetic
wave-shielding film for a plasma display panel utilizing the
light-transmitting electromagnetic wave-shielding film obtained by
the above-mentioned production method and a plasma display panel
using the same.
[0034] Further, as described above, in the conventional printed
boards and production methods thereof, there have been the problems
with regard to side etching, pinholes, cost and the like.
[0035] The wiring width is required to have a narrow pitch from the
demand for a recent increase in density of wiring. From this, a
copper foil or copper film is required to be thinned. However, when
it is thinned, pinhole characteristics are deteriorated. As
described above, the compatibility of an increase in density of
wiring and pinhole characteristics is in a difficult state.
Further, when the through hole plating time is taken long intending
to secure conductivity in a double-sided printed board, the
conductor thickness increases to degrade flexibility, resulting in
the difficulty of the compatibility of conductivity and
flexibility.
[0036] Furthermore, a method for forming a conductive metallic
silver pattern using a conventional silver salt light-sensitive
material has been insufficient for utilization as a printed board
material in terms of conductivity and insulating properties between
conducting wires.
[0037] The invention has been made in view of such a situation, and
therefore, still another specific object of the invention is to
provide a method for producing a printed board material
simultaneously having high conductivity and high insulating
properties, and having no pinholes, with easy formation of a fine
line pattern and small environmental loading at low cost in large
amounts, and further to provide a silver salt light-sensitive
material which becomes extremely advantageous for the production
thereof. Yet still another object of the invention is to provide a
printed wiring board obtained by the above-mentioned production
method.
[0038] The present inventors have made intensive studies of
simultaneously obtaining high conductivity, electromagnetic
wave-shielding properties and high translucency, and simultaneously
obtaining high conductivity and high insulating properties, for
conductive electromagnetic wave-shielding films. As a result, it
has been found that a significant increase in conductivity is
obtained by performing a smoothing treatment in a production
process, and it has been revealed that the above-mentioned two
kinds of problems of the conductive film to be solved can be
achieved by utilizing this phenomenon. That is to say, the
invention has been accomplished by the following methods for
producing a conductive film.
[0039] (1) A method for producing a conductive film, which
comprises:
[0040] exposing and developing a light-sensitive material
comprising a support and thereon an emulsion layer containing a
silver salt emulsion to form a metallic silver portion; and
then
[0041] subjecting the light-sensitive material to a smoothing
treatment.
[0042] (2) The method as described in (1) above, which
comprises:
[0043] exposing and developing a light-sensitive material
comprising a support and thereon an emulsion layer containing a
silver salt emulsion to form a metallic silver portion and a
light-transmitting portion; and then
[0044] subjecting the light-sensitive material to a smoothing
treatment.
[0045] (3) The method as described in (I) above, which
comprises:
[0046] exposing and developing a light-sensitive material
comprising a support and thereon an emulsion layer containing a
silver salt emulsion to form a metallic silver portion and an
insulating portion; and then
[0047] subjecting the light-sensitive material to a smoothing
treatment.
[0048] (4) The method as described in any one of (1) to (3)
above,
[0049] wherein the metallic silver portion after the smoothing
treatment comprises a silver and a non-conductive polymer, and
[0050] wherein a volume ratio of Ag/the non-conductive polymer is
2/1 or more.
[0051] (5) The method as described in any one of (1) to (4)
above,
[0052] wherein the metallic silver portion after the smoothing
treatment comprises a silver and a non-conductive polymer, and
[0053] wherein a volume ratio of Ag/the non-conductive polymer is
3/1 or more.
[0054] (6) The method as described in any one of (1) to (5)
above,
[0055] wherein 50% or more of a volume of the non-conductive
polymer is occupied by gelatin.
[0056] (7) The method as described in any one of (1) to (6) above,
which further comprises:
[0057] dipping the light-sensitive material in an aqueous solution
of a reducing agent between after the developing treatment and to
the smoothing treatment.
[0058] (8) The method as described in any one of (1) to (7) above,
which further comprises:
[0059] subjecting a surface of the metallic silver portion to a
blackening treatment after the smoothing treatment.
[0060] (9) The method as described in (8) above,
[0061] wherein a solution for the blackening treatment contains at
least one of nickel, zinc and tin.
[0062] (10) The method as described in any one of (1) to (9)
above,
[0063] wherein the smoothing treatment is performed with a calender
roll unit.
[0064] (11) The method as described in (10) above,
[0065] wherein the smoothing treatment with the calender roll unit
is performed at a line pressure of 980 N/cm (100 kgf/cm) or
more.
[0066] (12) The method as described in (10) or (11) above,
[0067] wherein the smoothing treatment with the calender roll unit
is performed at a line pressure of 1960 N/cm (200 kgf/cm) or
more.
[0068] (13) The method as described in any one of (10) to (12)
above,
[0069] wherein the smoothing treatment with the calender roll unit
is performed at a line pressure of 2940 N/cm (300 kgf/cm) or
more.
[0070] (14) The method as described in any one of (1) to (13)
above,
[0071] wherein a volume ratio of Ag/a binder in the emulsion layer
is 1/2 or more.
[0072] (15) The method as described in any one of (1) to (14)
above,
[0073] wherein a volume ratio of Ag/a binder in the emulsion layer
is 1/1 or more.
[0074] (16) The method as described in any one of (1) to (15)
above,
[0075] wherein a volume ratio of Ag/a binder in the emulsion layer
is 2/1 or more.
[0076] (17) The method as described in any one of (1) to (16)
above,
[0077] wherein the silver salt emulsion contained in the emulsion
layer is a silver halide.
[0078] (18) The method as described in (17) above,
[0079] wherein the silver halide is mainly composed of a silver
chloride.
[0080] (19) The method as described in (17) or (18) above,
[0081] wherein the silver halide comprises at least one of a
rhodium compound and an iridium compound.
[0082] (20) The method as described in any one of (1) to (19)
above,
[0083] wherein the emulsion layer is provided on both sides of the
support.
[0084] (21) The method as described in any one of (1) to (20)
above,
[0085] wherein the support has flexibility.
[0086] (22) The method as described in any one of (1) to (21)
above,
[0087] wherein the support is a polyethylene terephthalate (PET)
film.
[0088] (23) The method as described in any one of (1) to (21)
above,
[0089] wherein the support is a polyimide film.
[0090] (24) The method as described in any one of (1) to (23)
above,
[0091] wherein the emulsion layer is disposed substantially as an
uppermost layer, and contains at least one of a matting agent, a
lubricant, a colloidal silica and an antistatic agent.
[0092] (25) A method for producing a conductive film, comprising
any combination of (I) to (24) above.
[0093] (26) The method as described in any one of (1) to (25)
above,
[0094] wherein the exposure is performed by a scanning exposure
system with a laser beam.
[0095] (27) The method as described in any one of (1) to (25)
above,
[0096] wherein the exposure is performed through a photomask.
[0097] (28) The method as described in any one of (1) to (27)
above,
[0098] wherein a developing solution used in the development of the
emulsion layer contains an image quality improver.
[0099] (29) The method as described in any one of (1) to (28)
above,
[0100] wherein a developing solution used in the development of the
emulsion layer is a lithographic developing solution.
[0101] (30) The method as described in any one of (1) to (29)
above,
[0102] wherein a content of the metallic silver contained in an
exposed area after the development is 50% or more by mass based on
a mass of a silver contained in the exposed area before the
exposure.
[0103] (31) The method as described in any one of (1) to (30)
above,
[0104] wherein a gradation after the development of the emulsion
layer exceeds 4.0.
[0105] (32) The method as described in any one of (2) and (4) to
(31) above,
[0106] wherein the light-transmitting portion does not
substantially have physical development nuclei.
[0107] (33) A conductive film obtained by a production method as
described in any one of (1) to (32) above.
[0108] (34) The conductive film as described in (33) above, which
is an electromagnetic wave-shielding film.
[0109] (35) The conductive film as described in (33) above, which
is a printed wiring board.
[0110] (36) The conductive film as described in any one of (33) to
(35) above, which comprises
[0111] a support and thereon
[0112] a metal wiring pattern containing a silver at a density of
8.0 g/cm.sup.3 to 10.5 g/cm.sup.3.
[0113] (37) The conductive film as described in (36) above,
[0114] wherein a thickness of the metal wiring pattern is from 0.5
.mu.m to 5 .mu.m.
[0115] (54) The method as described in (10) above,
[0116] wherein the smoothing treatment with the calender roll unit
is performed at a line pressure of 6,860 N/cm (700 kgf/cm) or
less.
[0117] (55) The method as described in (54) above, which further
comprises:
[0118] dipping the light-sensitive material in an aqueous solution
of a reducing agent between after the developing treatment and to
the smoothing treatment.
[0119] Further, the object of the invention is achieved by a
light-transmitting electromagnetic wave-shielding film comprising
the following embodiments.
[0120] (38) A light-transmitting electromagnetic wave-shielding
film having a conductive metal portion and a light-transmitting
portion, which is obtained by a method as described in any one of
(1) to (32) above.
[0121] (39) The light-transmitting electromagnetic wave-shielding
film as described in (38) above,
[0122] wherein a shape of the conductive metal portion is a mesh
form.
[0123] (40) The light-transmitting electromagnetic wave-shielding
film as described in (38) or (39) above,
[0124] wherein an open area ratio of the conductive metal portion
is 85% or more.
[0125] (41) The light-transmitting electromagnetic wave-shielding
film as described in any one of (38) to (40) above,
[0126] wherein a line width of the conductive metal portion is from
0.1 .mu.m to less than 18 .mu.m.
[0127] (42) The light-transmitting electromagnetic wave-shielding
film as described in any one of (38) to (41) above,
[0128] wherein a line width of the conductive metal portion is from
0.1 .mu.m to less than 14 .mu.m.
[0129] (43) The light-transmitting electromagnetic wave-shielding
film as described in any one of (38) to (42) above,
[0130] wherein a line width of the conductive metal portion is from
0.1 .mu.m to less than 10 .mu.m.
[0131] (44) The light-transmitting electromagnetic wave-shielding
film as described in any one of (38) to (43) above,
[0132] wherein a line width of the conductive metal portion is from
0.1 .mu.m to less than 7 .mu.m.
[0133] Furthermore, the object of the invention is achieved by a
printed board comprising the following embodiments,
[0134] (45) A printed board having a conductive metal portion and
an insulating portion, which is obtained by a production method as
described in any one of (1) to (32) above.
[0135] (46) The printed board as described in (45) above,
[0136] wherein a line width of the conductive metal portion is from
0.1 .mu.m to less than 18 .mu.m.
[0137] (47) The printed board as described in (45) or (46)
above,
[0138] wherein a line width of the conductive metal portion is from
0.1 .mu.m to less than 14 .mu.m.
[0139] (48) The printed board as described in any one of (45) to
(47) above,
[0140] wherein a line width of the conductive metal portion is from
0.1 .mu.m to less than 10 .mu.m.
[0141] (49) The printed board as described in any one of (45) to
(48) above,
[0142] wherein a line width of the conductive metal portion is from
0.1 .mu.m to less than 7 .mu.m.
[0143] (50) A conductive film, which comprises
[0144] a support and thereon
[0145] a metal wiring pattern,
[0146] wherein the metal wiring pattern is subjected to a smoothing
treatment.
[0147] (51) The conductive film as described in (50) above,
[0148] wherein the metal wiring pattern contains a silver at a
density of 8.0 g/cm.sup.3 to 10.5 g/cm.sup.3.
[0149] (52) The conductive film as described in (50) or (51)
above,
[0150] wherein a thickness of the metal wiring pattern is from 0.5
.mu.m to 5 .mu.m.
[0151] (53) The conductive film as described in any one of (50) to
(52) above,
[0152] wherein a line width of the metal wiring pattern is from 0.1
.mu.m to less than 18 .mu.m.
BRIEF DESCRIPTION OF THE DRAWINGS
[0153] FIG. 1 represents the relationship between line pressure and
surface resistivity in the calender treatment after development and
the calender treatment after fixing;
[0154] FIG. 2 represents an explanatory drawing of the flexing
test;
[0155] FIGS. 3A and 3B represent the drawings of the photographs of
the samples;
[0156] FIG. 4 represents an explanatory drawing for measuring the
brightness;
[0157] FIG. 5 represents the measurement results of brightness
ratio; and
[0158] FIG. 6 represents the increase rate of surface
resistance.
BEST MODE FOR CARRYING OUT THE INVENTION
[0159] The methods for producing conductive films according to the
invention, particularly the method for producing a
light-transmitting electromagnetic wave-shielding film and the
method for producing a printed board, will be described in detail
below.
[0160] In the present specification, "to" indicating the range is
used as including numerical values described before and after it as
a lower limit value and an upper limit value, respectively.
[0161] (Light-Sensitive Materials for Conductive Film
Production)
[0162] [Support]
[0163] As the support of the light-sensitive material used in the
production method of the invention, there can be used a plastic
film, a plastic plate, a glass plate or the like.
[0164] As raw materials for the above-mentioned plastic film and
plastic plate, there can be used polyesters such as polyethylene
terephthalate (PET) and polyethylene naphthalate; polyolefins such
as polyethylene (PE), polypropylene (PP), polystyrene and EVA;
vinyl resins such as polyvinyl chloride and polyvinylidene
chloride; polyether ether ketones (PEEK), polysulfones (PSF),
polyether sulfones (PES), polycarbonates (PC), polyamides,
polyimides, acrylic resins, triacetyl cellulose (TAC) and the
like.
[0165] The plastic film and plastic plate in the invention can be
used as a monolayer, or can also be used as a multilayer film in
which two or more layers are combined.
[0166] Further, a metal foil support such as aluminum can also be
used.
[0167] [Silver Salt-Containing Layer]
[0168] The light-sensitive material used in the production method
of the invention has an emulsion layer containing a silver salt
emulsion (silver salt-containing layer) on the support as an
optical sensor. The silver salt-containing layer can contain a
binder, a solvent and the like, in addition to the silver salt.
Further, when there is no doubt, the emulsion layer containing a
silver salt emulsion (or the silver salt-containing layer) is
simply called "the emulsion layer" in some cases.
[0169] Furthermore, the emulsion layer is preferably disposed
substantially as an uppermost layer. "The emulsion layer is
disposed substantially as an uppermost layer" as used herein means
not only the case where the emulsion layer is actually disposed as
an upper layer, but also the case where the total film thickness of
a layer provided on the emulsion layer is 0.5 .mu.m or less. The
total film thickness of the layer provided on the emulsion layer is
preferably 0.2 .mu.m or less.
[0170] The emulsion layer can contain a dye, a binder, a solvent
and the like as needed. The respective components contained in the
emulsion layer will be explained below.
[0171] <Dye>
[0172] In the light-sensitive material, at least the dye may be
contained in the emulsion layer. The dye is contained in the
emulsion layer as a filter dye or for various purposes such as
prevention of irradiation. As the above-mentioned dye, a solid
disperse dye may be contained. The dyes preferably used in the
invention include dyes represented by general formula (FA), general
formula (FA1), general formula (FA2) and general formula (FA3)
described in JP-A-9-179243, and specifically, compounds F1 to F34
described in ibid. are preferred. Further, (II-2) to (II-24)
described in JP-A-7-152112, (III-5) to (III-18) described in
JP-A-7-152112 (IV-2) to (IV-7) described in JP-A-7-152112, and the
like are also preferably used.
[0173] In addition, the dyes which can be used in the invention
include a cyanine dye, a pyrylium dye and an aluminum dye which are
described in JP-A-3-138640, as fine solid particle dispersion type
dyes decolorized at the time of development or fixing. Further,
dyes not decolorized at the time of the treatment include a
carboxyl group-containing cyanine dye described in JP-A-9-96891, a
cyanine dye containing no acidic group described in JP-A-8-245902,
a lake type cyanine dye described in JP-A-8-333519, a cyanine dye
described in JP-A-1-266536, a holopolar type cyanine dye described
in JP-A-3-136038, a pyrylium dye described in JP-A-62-299959, a
polymer type cyanine dye described in JP-A-7-253639, a fine solid
particle dispersion of a an oxonol dye described in JP-A-2-282244,
light-scattering particles described in JP-A-63-131135, a Yb3+
compound described in JP-A-9-5913, an ITO powder described in
JP-A-7-113072, and the like. Further, dyes represented by general
formula (F1) and general formula (F2) described in JP-A-9-179243,
specifically compounds F35 to F112 described in ibid., can also be
used.
[0174] The above-mentioned dyes include water-soluble dyes. Such
water-soluble dyes include an oxonol dye, a benzylidene dye, a
merocyanine dye, a cyanine dye and an azo dye. Above all, an oxonol
dye, a hemioxonol dye and a benzylidene dye are useful in the
invention. Specific examples of the water-soluble dyes that can be
used in the invention include ones described in British Patents
584,609 and 1,177,429, JP-A-48-85130, JP-A-49-99620,
JP-A-49-114420, JP-A-52-20822, JP-A-59-154439, JP-A-59-208548, U.S.
Pat. Nos. 2,274,782, 2,533,472, 2,956,879, 3,148,187, 3,177,078,
3,247,127, 3,540,887, 3,575,704, 3,653,905 and 3,718,427.
[0175] The content of the dye in the above-mentioned emulsion layer
is preferably from 0.01 to 10% by mass, and more preferably from
0.1 to 5% by mass, based on the total solid content, from the
viewpoints of the effect of irradiation prevention and a decrease
in sensitivity due to an increase in the amount added. (In this
specification, mass ratio is equal to weight ratio.)
[0176] <Silver Salt>
[0177] Examples of the silver salt used in the invention include
inorganic silver salts such as silver halides and organic silver
salts such as silver acetate. In the invention, silver halides that
are excellent in characteristics as an optical sensor are
preferably used.
[0178] The silver halides preferably used in the invention will be
explained.
[0179] In the invention, the silver halides which are excellent in
characteristics as an optical sensor are preferably used, and
techniques used in silver salt photographic films relating to
silver halides, photographic paper, films for printing plate
making, emulsion masks for photomasks and the like can also be used
in the invention.
[0180] A halogen element contained in the above-mentioned silver
halide may be any of chlorine, bromine, iodine and fluorine, or
they may be combined. For example, a silver halide mainly
comprising AgCl, AgBr or AgI is preferably used, and further, a
silver halide mainly comprising AgBr or AgCl is more preferably
used. Silver chlorobromide, silver iodochlorobromide silver
iodobromide are also preferably used. More preferred are silver
chlorobromide, silver bromide and silver iodobromide, and silver
chlorobromide and silver iodochlorobromide that contain 50 mol % or
more of silver chloride are most preferably used.
[0181] The term "a silver halide mainly comprising AgBr (silver
bromide)" as used herein means a silver halide in which the molar
fraction of bromide ions occupying in a silver halide composition
is 50% or more. Such silver halide grains mainly comprising AgBr
may contain iodide ions and chloride ions, in addition to the
bromide ions.
[0182] The silver iodide content in the silver halide emulsion is
preferably 1.5 mol % per mol of silver halide emulsion. Adjustment
of the silver iodide content to 1.5 mol % can prevent fogging and
improve pressure properties. The silver iodide content is more
preferably 1 mol % or less per mol of silver halide emulsion.
[0183] The silver halide is in solid grain form. From the viewpoint
of image quality of a patterned metallic silver layer formed after
exposure and development, the average grain size of the silver
halide is preferably from 0.1 to 1000 nm (1 .mu.m), more preferably
from 0.1 to 100 nm, and still more preferably from 1 to 50 nm, in
terms of the sphere-corresponding diameter. The
sphere-corresponding diameter of silver halide grains means the
diameter of a grain having a spherical grain shape and the same
volume.
[0184] The shape of the silver halide grain is not particularly
limited, and the grain can be of various shapes, for example,
spherical, cubic, tabular (hexagonal tabular, triangular tabular,
square tabular and the like), octahedral, tetradecahedral shapes
and the like.
[0185] The inside and a surface layer of the silver halide grain
may be composed of either a homogeneous phase or different phases,
respectively. Further, the inside or the surface of the grain may
have a localized layer different in halogen composition.
[0186] The silver halide emulsion which is a coating solution for
the emulsion layer used in the invention can be prepared by methods
described in P. Glafkides, Chimie et Physique Photographique
(published by Paul Montel, 1967), G. F. Duffin, Photographic
Emulsion Chemistry (published by The Forcal Press, 1966), V. L.
Zelikman et al., Making and Coating Photographic Emulsion
(published by The Forcal Press, 1964) and the like.
[0187] That is to say, a method for preparing the above-mentioned
silver halide emulsion may be any of an acidic method, a neutral
method and the like. As a method for reacting a soluble silver salt
with a soluble halogen salt, there may be used any of a single jet
method, a double jet method, a combination thereof and the
like.
[0188] Further, as a method for forming silver grains, there can
also be used a method of forming the grains in the presence of
excess silver ions (so-called reverse mixing method). Furthermore,
as one type of the double jet method, there can also be used a
method of keeping constant the pAg in a liquid phase in which the
silver halide is formed, that is to say, a so-called controlled
double jet method.
[0189] In addition, it is also preferred that the formation of the
silver halide grains is performed using a so-called silver halide
solvent such as ammonia, a thioether or a tetrasubstituted
thiourea. In such a method, more preferred is a tetrasubstituted
thiourea, which is described in JP-A-53-82408 and JP-A-55-77737.
Preferred examples of the thiourea compounds include
tetramethylthiourea and 1,3-dimethyl-2-imidazolidinethione.
Although the amount of the silver halide solvent added varies
depending on the kind of compound used, the desired grain size and
the halogen composition, it is preferably form 10.sup.-5 to
10.sup.-2 mol per mol of silver halide.
[0190] According to the grain formation method using the
above-mentioned controlled double jet method and silver halide
solvent, a silver halide emulsion having a regular crystal form and
a narrow grain size distribution is easily produced. This method
can be therefore preferably used in the invention
[0191] In order to make the grain size uniform, it is preferred
that silver is allowed to glow rapidly within the range not
exceeding the critical degree of saturation, using a method of
changing the rate of addition of silver nitrate or an alkali halide
depending on the grain growth rate, as described in British Patent
1,535,016, JP-B-48-36890 and JP-B-52-16364, or a method of changing
the concentration of the aqueous solution, as described in British
Patent 4,242,445 and JP-A-55-158124. The silver halide emulsion
used in the formation of the emulsion layer in the invention is
preferably a monodisperse emulsion, and the coefficient of
variation represented by (standard deviation of grain size/average
grain size).times.100 is preferably 20% or less, more preferably
15% or less, and most preferably 10% or less.
[0192] The silver halide emulsion used in the invention may be a
mixture of plural kinds of silver halide emulsions different in
grain size.
[0193] The silver halide emulsion used in the invention may contain
a metal belonging to group VIII or group VIIB. In particular, in
order to achieve high contrast and low fogging, it is preferred to
contain a rhodium compound, an iridium compound, a ruthenium
compound, an iron compound, an osmium compound or the like. These
compounds may be compounds having various kinds of ligands. The
ligands include, for example, cyanide ions, halogen ions,
thiocyanate ions, nitrosyl ions, water, hydroxide ions and the
like, and in addition to such pseudohalogens and ammonia, organic
molecules such as amines (methylamine, ethylenediamine and the
like), heterocyclic compounds (imidazole, thiazole,
5-methylthiazole, mercaptoimidazole and the like), urea and
thiourea.
[0194] Further, for high sensitization, doping of a hexa-cyanated
metal complex such as K.sub.4[Fe(CN).sub.6], K.sub.4[Ru(CN).sub.6]
or K.sub.3[Cr(CN).sub.6] is advantageously performed.
[0195] As the above-mentioned rhodium compound, a water-soluble
rhodium compound can be used. The water-soluble rhodium compounds
include, for example, a rhodium (III) halide compound, a
hexachlororhodium (III) complex salt, a pentachloroaquorhodium
(III) complex salt, a tetrachlorodiaquorhodium (III) complex salt,
a hexabromorhodium (III) complex salt, a hexaamminerhodium (III)
complex salt, a trioxalatorhodium (III) complex salt,
K.sub.3Rh.sub.2Br.sub.9 and the like.
[0196] These rhodium compounds are dissolved in water or a suitable
solvent to be used. There can be used a method commonly employed
for stabilizing a solution of a rhodium compound, that is to say, a
method of adding an aqueous solution of a hydrogen halide (for
example, hydrochloric acid, hydrobromic acid or hydrofluoric acid)
or an alkali halide (for example, KCl, NaCl, KBr or NaBr). Instead
of using the water-soluble rhodium, it is also possible to add and
dissolve other silver halide grains previously doped with rhodium,
in the preparation of silver halide.
[0197] The above-mentioned iridium compounds used in the invention
include a hexachloroiridium complex salt such as K.sub.2IrCl.sub.6
or K.sub.3IrCl.sub.6, a hexabromoiridium complex salt, a
hexaammineiridium complex salt, a pentachloronitrosyliridium
complex salt and the like.
[0198] The above-mentioned ruthenium compounds include
hexachlororuthenium, pentachloronitrosylruthenium,
K.sub.4[Ru(CN).sub.6] and the like.
[0199] The above-mentioned iron compounds include potassium
hexacyanoferrate (III) and ferrous thiocyanate.
[0200] Ruthenium and osmium described above are added in the form
of water-soluble complex salts described in JP-A-63-2042,
JP-A-1-285941, JP-A-2-20852, JP-A-2-20855 and the like, and
particularly preferred examples thereof include a hexa-coordinated
complex represented by the following formula:
[ML.sub.6].sup.-n
wherein M represents Ru or Os, and n represents 0, 1, 2, 3 or
4.
[0201] In this case, a counter ion has no importance, and, for
example, an ammonium or alkali metal ion is used. Preferred
examples of the ligands include a halide ligand, a cyanide ligand,
a cyanate ligand, a nitrosyl ligand, a thionitrosyl ligand and the
like. Specific examples of the complexes used in the invention are
shown below, but the invention should not be construed as being
limited thereto.
[0202] [RuCl.sub.6].sup.-3, [RuCl.sub.4(H.sub.2O).sub.2].sup.-1,
[RuCl.sub.5(NO)].sup.-2, [RuBr.sub.5(NS)].sup.-2,
[Ru(CO).sub.3Cl.sub.3].sup.-2, [Ru(CO)Cl.sub.5].sup.-2,
[Ru(CO)Br.sub.5].sup.-2, [OsCl.sub.6].sup.-3,
[OsCl.sub.5(NO)].sup.-2, (Os(NO)(CN).sub.5].sup.-2,
[Os(NS)Br.sub.5].sup.-2 and [Os(O).sub.2(CN).sub.4].sup.-4
[0203] The amount of these compounds added is preferably from
10.sup.-10 to 10.sup.-2 mol/mol Ag, and more preferably from
10.sup.-9 to 10.sup.-3 Ag, per mol of silver halide.
[0204] In addition, a silver halide containing a Pd(II) ion and/or
Pd metal can also be preferably used in the invention. Pd may be
uniformly distributed in a silver halide grain. However, it is
preferably contained in the vicinity of a surface layer of the
silver halide grain. The expression "Pd is contained in the
vicinity of a surface layer of the silver halide grain" as used
herein means that the grain has a layer having a higher content of
palladium within a thickness of 50 nm from the surface of the
silver halide grain in the depth direction than the other
layers.
[0205] Such silver halide grains can be formed by adding Pd in the
course of the formation of the silver halide grains. It is
preferred that Pd is added after silver ions and halogen ions have
each been added in an amount of 50% or more of the total amount
added. Further, it is also preferred that Pd(II) ions are allowed
to exist in the silver halide surface layer by a method of adding
the ions at the time of post-ripening, or the like.
[0206] These Pd-containing silver halide grains enhance the speeds
of physical development and electroless plating to increase the
production efficiency of a desired electromagnetic wave-shielding
material, thereby contributing to a reduction in production cost.
Pd is well known and used as an electroless plating catalyst. In
the invention, however, Pd can be localized in the surface layer of
the silver halide grain, so that extremely expensive Pd can be
saved.
[0207] In the invention, the content of Pd ions and/or Pd metal
contained in the silver halide is preferably from 10.sup.-4 to 0.5
mol/mol Ag, and more preferably from 0.01 to 0.3 mol/mol Ag, based
on the molar number of silver in the silver halide.
[0208] Examples of the Pd compounds used include PdCl.sub.4,
Na.sub.2PdCl.sub.4 and the like.
[0209] In the invention, chemical sensitization may be performed or
not, similarly to the case of general silver halide photographic
light-sensitive materials. The chemical sensitization is performed,
for example, by adding to a silver halide emulsion a chemical
sensitizer comprising a cicogenite compound or a noble metal
compound which has the function of enhancing the sensitivity of a
photographic light-sensitive material, which is described in
JP-A-2000-275770, paragraph number 0078 and later. As the silver
salt emulsion used in the light-sensitive material of the
invention, there can be preferably used an emulsion not subjected
to such chemical sensitization, that is to say, a chemically
unsensitized emulsion. As a preferred method for preparing the
chemically unsensitized emulsion in the invention, it is preferred
that the amount of the chemical sensitizer comprising a cicogenite
compound or a noble metal compound added is limited to an amount
equal to or less than such an amount that an increase in
sensitivity caused by the addition thereof is within 0.1. There is
no limitation on the specific amount of the cicogenite or noble
metal compound added. However, as the preferred method for
preparing the chemically unsensitized emulsion in the invention, it
is preferred that the total amount of these chemical sensitizing
compounds is adjusted to 5.times.10.sup.-7 mol or less per mol of
silver halide.
[0210] In the invention, in order to further improve sensitivity as
an optical sensor, chemical sensitization that is carried out for
photographic emulsions can also be performed. As methods for the
chemical sensitization, there can be used, for example, chalcogen
sensitization such as sulfur sensitization, selenium sensitization
and tellurium sensitization, noble metal sensitization such as gold
sensitization, reduction sensitization and the like. These are used
alone or in combination. When the above-mentioned methods for the
chemical sensitization are used in combination, for example,
combinations of sulfur sensitization and gold sensitization, sulfur
sensitization, selenium sensitization and gold sensitization,
sulfur sensitization, tellurium sensitization and gold
sensitization, and the like are preferred.
[0211] The above-mentioned sulfur sensitization is usually
performed by adding a sulfur sensitizer and stirring the emulsion
at a temperature as high as 40.degree. C. or higher for a
predetermined time. As the above-mentioned sulfur sensitizer, a
well-known compound can be used. For example, in addition to sulfur
compounds contained in gelatin, various sulfur compounds such as
thiosulfates, thioureas, thiazoles and rhodanines can be used.
Preferred examples of the sulfur compounds are thiosulfates and
thiourea compounds. The amount of the sulfur sensitizer added
varies depending on various conditions such as the pH, the
temperature and the grain size of silver halide at the time of
chemical ripening, and it is preferably from 10.sup.-7 to10.sup.-2
mole per mole of silver halide, and more preferably from 10.sup.-5
to10.sup.-3 mole.
[0212] As a selenium sensitizer used in the above-mentioned
selenium sensitization, a well-known selenium compound can be used.
That is to say, the above-mentioned selenium sensitization is
usually performed by adding an unstable type selenium compound
and/or a non-unstable type selenium compound and stirring the
emulsion at a high temperature of 40.degree. C. or higher for a
predetermined time. As the above-mentioned unstable type compounds,
there can be used compounds described in JP-B-44-15748,
JP-B-43-13489, JP-A-4-109240, JP-A-4-324855 and the like. In
particular, compounds represented by general formulas (VIII) and
(IX) in JP-A-4-324855 are preferably used.
[0213] A tellurium sensitizer used in the above-mentioned tellurium
sensitization is a compound that forms silver telluride presumed to
become a sensitization nucleus in a surface or an interior of a
silver halide grain. The formation rate of silver telluride in the
silver halide emulsion can be examined according to a method
disclosed in JP-A-5-313284. Specifically, there can be used
compounds described in U.S. Pat. Nos. 1,623,499, 3,320,069,
3,772,031, British Patents 235,211, 1,121,496, 1,295,462,
1,396,696, Canadian Patent 800,958, JP-A-4-204640, JP-A-4-271341,
JP-A-4-333043, JP-A-5-303157, J. Chem. Soc. Chem. Commun., 635
(1980), ibid., 1102 (1979), ibid., 645 (1979), J. Chem. Soc.
Perkin. Trans., 1, 2191 (1980), edited by S. Patai, The Chemistry
of Organic Selenium and Tellurium Compounds, Vol. 1 (1986), and
ibid., Vol. 2 (1987). In particular, compounds represented by
general formulas (II), (III) and (IV) in JP-A-5-313284 are
preferred.
[0214] The amounts of the selenium sensitizer and the tellurium
sensitizer which can be used in the invention vary depending on the
silver halide grains used and the conditions of chemical ripening,
but are generally from about 10.sup.-8 to 10.sup.-2 mol, and
preferably from about 10.sup.-7 to 10.sup.-3 mol, per mol of silver
halide. There is no particular limitation on the conditions of
chemical sensitization in the invention, However, the pH is from 5
to 8, the pAg is from 6 to 11, and preferably from 7 to 10, and the
temperature is from 40 to 95.degree. C., and preferably from 45 to
85.degree. C.
[0215] Further, noble metal sensitizers include gold, platinum,
palladium, iridium and the like, and gold sensitization is
particularly preferred. The gold sensitizers used in the gold
sensitization include chloroauric acid, potassium chloroaurate,
potassium aurithiocyanate, gold sulfide, thioglucose gold (I),
thiomannose gold (I) and the like, which can be used in an amount
of about 10.sup.-7 to 10.sup.-2 mol per mol of silver halide. In
the silver halide emulsion used in the invention, a cadmium salt, a
sulfite, a lead salt, a thallium salt or the like may be allowed to
coexist in the course of the formation of the silver halide grains
or physical ripening.
[0216] Further, in the invention, reduction sensitization can be
used. As reduction sensitizers, there can be used stannous salts,
amines, formamidinesulfinic acids, silane compounds and the like. A
thiosulfonic acid compound may be added to the above-mentioned
silver halide emulsion according to a method shown in European
Laid-Open Patent (EP) 293917. The silver halide emulsions used in
the preparation of the light-sensitive material used in the
invention may be used either alone or as a combination of two or
more thereof (for example, different in average grain size,
different in halogen composition, different in crystal habit,
different in chemical sensitization conditions or differing in
sensitivity). Above all, in order to obtain high contrast, it is
preferred to apply an emulsion having a higher sensitivity to
closer to a support, as disclosed in JP-A-6-324426.
[0217] In the emulsion layer, a binder can be used in order to
uniformly disperse the silver salt grains and assist adhesion of
the emulsion layer and the support. In the invention, although
either a water-insoluble polymer or a water-soluble polymer can be
used as the binder, a water-soluble polymer is preferably used.
[0218] The above-mentioned binders include, for example, gelatin,
polyvinyl alcohol (PVA), polyvinylpyrrolidine (PVP), a
polysaccharide such as starch, cellulose and a derivative thereof,
polyethylene oxide, polyvinylamine, chitosan, polylysine,
polyacrylic acid, polyalginic acid, polyhyaluronic acid,
carboxycellulose and the like. These have a neutral, anionic or
cationic property depending on the ionicity of functional groups.
Further, as the gelatin, there may be used acid treated gelatin as
well as lime treated gelatin. A hydrolyzate of gelatin, an enzyme
degradation product of gelatin and amino group-modified or carboxyl
group-modified gelatin (phthalated gelatin or acetylated gelatin)
can also be used.
[0219] The content of the binder contained in the emulsion layer is
not particularly limited and can be appropriately determined within
the range in which dispersibility and adhesion can be exerted. The
content of the binder in the emulsion layer is preferably 1/2 or
more, and more preferably 1/1 or more, by the volume ratio of
Ag/binder.
[0220] <Solvent>
[0221] Although the solvent used for the formation of the
above-mentioned emulsion layer is not particularly limited,
examples thereof include water, organic solvents (for example, an
alcohol such as methanol, a ketone such as acetone, an amide such
as formamide, a sulfoxide such as dimethyl sulfoxide, an ester such
as ethyl acetate, an ether and the like), ionic liquids and mixed
solvents thereof.
[0222] The content of the solvent used in the emulsion layer of the
invention is within the range of 30 to 90% by mass, and preferably
within the range of 50 to 80% by mass, based on the total mass of
silver salt, binder and the like contained in the above-mentioned
emulsion layer.
[0223] <Antistatic Agent>
[0224] The light-sensitive material according to the invention
preferably contains an antistatic agent, and it is desirable that a
support surface on the opposite side of the emulsion layer is
coated therewith.
[0225] As an antistatic layer, there can be used a conductive
material-containing layer having a surface resistivity of
10.sup.12.OMEGA. or less under the atmosphere of 25.degree. C. and
25% RH. As the antistatic agents preferred in the invention, the
following conductive materials can be preferably used.
[0226] There can be used conductive materials described in
JP-A-2-18542, from page 2, lower left column, line 13 to page 3,
upper right column, line 7, specifically, metal oxides described at
page 2, lower right column, lines 2 to 10 and conductive polymer
compounds of compounds P-1 to P-7, acicular metal oxides described
in U.S. Pat. No. 5,575,957, JP-A-10-142738, paragraph numbers 0045
to 0043 and JP-A-11-223901, paragraph numbers 0013 to 0019, and the
like.
[0227] The conductive metal oxide particles used in the invention
include ZnO, TiO.sub.2, SnO.sub.2; Al.sub.2O.sub.3,
In.sub.2O.sub.3, MgO, BaO, MoO.sub.3 and composite metal oxides
there and particles of metal oxides in which these metal oxides
further contain different kinds of atoms. As the metal oxides,
SnO.sub.2, ZnO, Al.sub.2O.sub.3, TiO.sub.2, In.sub.2O.sub.3 and MgO
are preferred, SnO.sub.2, ZnO, In.sub.2O.sub.3 and TiO2 are more
preferred, and SnO.sub.2 is particularly preferred. Examples of the
metal oxides containing different kinds of atoms in small amounts
include ZnO doped with Al or In, TiO.sub.2 doped with Nb or Ta,
In.sub.2O.sub.3 doped with Sn, and SnO.sub.2 doped with Sb, Nb or a
different kind of element such as a halogen atom in an amount of
0.01 to 30 mol % (preferably 0.1 to 10 mol %). When the amount of
the different kind of element added is 0.01 mol % or less, it
becomes difficult to impart sufficient conductivity to the oxide or
the composite oxide. Exceeding 30 mol % results in an increase in
blackening density of the particles, which unsuitably causes the
antistatic layer to become dark. Accordingly, in the invention, as
the material for the conductive metal oxide particles, preferred is
one containing the different kind of element in a small amount
based on the metal oxide or the composite metal oxide. Further, one
containing an oxygen defect in a crystal structure is also
preferred.
[0228] As the conductive fine metal oxide particles containing the
above-mentioned different kinds of atoms in small amounts,
antimony-doped SnO.sub.2 particles are preferred, and SnO.sub.2
particles doped with 0.2 to 2.0 mol % of antimony are particularly
preferred.
[0229] There is no particular limitation on the shape of the
conductive metal oxide used in the invention, and it is granular,
acicular or the like. Further, for the size thereof, the average
particle size represented by the sphere-corresponding diameter is
from 0.5 to 25 .mu.m.
[0230] Further, in order to obtain conductivity, there can also be
used, for example, a soluble salt (for example, a chloride, a
nitrate or the like), a deposited metal layer, an ionic polymer as
described in U.S. Pat. Nos. 2,861,056 and 3,206,312, or an
insoluble inorganic salt as described U.S. Pat. No. 3,428,451.
[0231] Such a conductive metal oxide particle-containing antistatic
layer is preferably provided as an undercoat layer for the back
face, an undercoat layer for the emulsion layer, or the like. The
amount thereof added is preferably from 0.01 to 1.0 g/m.sup.2 in
total in both faces.
[0232] Further, the internal resistivity of the light-sensitive
material is preferably from 1.0.times.10.sup.7 to
1.0.times.10.sup.12.OMEGA. under the atmosphere of 25.degree. C.
and 25% RH.
[0233] In the invention, fluorine-containing surfactants described
in JP-A-2-18542, page 4, from upper right column, line 2 to lower
right column, line 3 from the bottom and JP-A-3-39948, from page
12, lower left column, line 6 to page 13, lower right column, line
5 are used in combination with the above-mentioned conductive
material, thereby being able to obtain better antistatic
properties.
[0234] <Other Additives>
[0235] There is no particular limitation on various additives used
in the light-sensitive material in the invention, and, for example,
the following can be preferably used.
[0236] (1) Nucleation Accelerator
[0237] The above-mentioned nucleation accelerators include
compounds of general formulas (I), (II), (III), (IV), (V) and (IV)
described in JP-A-6-82943, compounds of general formulas (II-m) to
(II-p) and compound examples II-1 to 11-22 described in
JP-A-2-103536, from page 9, upper right column, line 13 to page 16,
upper left column, line 10, and compounds described in
JP-A-1-179939.
[0238] (2) Spectral Sensitizing Dye
[0239] The above-mentioned spectral sensitizing dyes include
spectral sensitizing dyes described in JP-A-2-12236, page 8, from
lower left column, line 13 to lower right column, line 4,
JP-A-2-103536, from page 16, lower right column, line 3 to page 17,
lower left column, line 20, JP-A-1-112235, JP-A-2-124560,
JP-A-3-7928 and JP-A-5-11389.
[0240] (3) Surfactant
[0241] The above-mentioned surfactants include surfactants
described in JP-A-2-12236, page 9, from upper right column, line 7
to lower right column, line 7 and JP-A-2-18542, from page 2, lower
left column, line 13 to page 4, lower right column, line 18.
[0242] (4) Antifoggant
[0243] The above-mentioned antifoggants include thiosulfinic acid
compounds described in JP-A-2-103536, from page 17, lower right
column, line 19 to page 18, upper right column, line 4 and page 18,
lower right column, from line 1 to line 5, and further
JP-A-1-237538.
[0244] (5) Polymer Latex
[0245] The above-mentioned polymer latexes include ones described
in JP-A-2-103536, page 18, lower left column, from line 12 to line
20.
[0246] (6) Acid Group-Containing Compound
[0247] The above-mentioned acid group-containing compounds include
compounds described in JP-A-2-103536, from page 18, lower right
column, line 6 to page 19, upper left column, line 1.
[0248] (7) Hardening Agent
[0249] The above-mentioned hardening agents include compounds
described in JP-A-2-103536, page 18, upper right column, from line
5 to line 17.
[0250] (8) Black Pepper Inhibitor
[0251] The above-mentioned black pepper inhibitor is a compound
that inhibits the production of dotted developed silver in an
unexposed area, and examples thereof include compounds described in
U.S. Pat. No. 4,956,257 and JP-A-1-118832.
[0252] (9) Redox Compound
[0253] The redox compounds include compounds represented by general
formula (1) (particularly compound examples 1 to 50) described in
JP-A-2-301743, compounds represented by general formulas (R-1),
(R-2) and (R-3) and compound examples 1 to 75 described in
JP-A-3-174143, from page 3 to page 20, and further, compounds
described in JP-A-5-257239 and JP-A-4-27899.
[0254] (10) Monomethine Compound
[0255] The above-mentioned monomethine compounds include compounds
represented by general formula (11) (particularly compound examples
II-1 to II-26) described in JP-A-2-287532.
[0256] (11) Dihydroxybenzene
[0257] The dihydroxybenzenes include compounds described in
JP-A-3-39948, from page 11, upper left column to page 12, lower
left column and European Laid-Open Patent EP-452772A.
[0258] <Method for Producing a Conductive Film>
[0259] There will be described a method for producing a conductive
film using the above-mentioned light-sensitive material.
[0260] The production method of the conductive film of the
invention comprises exposing and developing a light-sensitive
material having a silver salt emulsion-containing emulsion layer
provided on a support to form a metallic silver portion and a
light-transmitting portion or a metallic silver portion and an
insulating portion, followed by a smoothing treatment (for example,
a calender treatment).
[0261] The conductive film obtained according to the invention is a
film in which the metal is formed on the support by pattern
exposure, and the pattern exposure may be either a scanning
exposure system or a surface exposure system. Further, the metal
portion is formed in an exposed area in some cases, and in an
unexposed area in the other cases.
[0262] The pattern is a mesh-like pattern when used for the
production of the electromagnetic wave-shielding film, and a wiring
pattern when used for the production of the printed board. Further
details of the pattern shape can be appropriately adjusted
depending on the purpose.
[0263] The production method of the conductive film of the
invention includes the following three modes depending on the
light-sensitive material and development.
[0264] (1) A mode in which a photosensitive silver salt
black-and-white light-sensitive material containing no physical
development nuclei is subjected to chemical development or thermal
development to form the metallic silver portion on the
light-sensitive material;
[0265] (2) A mode in which a photosensitive silver salt
black-and-white light-sensitive material containing physical
development nuclei in the silver halide emulsion layer is subjected
to dissolution physical development to form the metallic silver
portion on the light-sensitive material; and
[0266] (3) A mode in which a photosensitive silver salt
black-and-white light-sensitive material containing no physical
development nuclei and an image receiving sheet having a
non-photosensitive layer containing physical development nuclei are
laminated with each other, and subjected to diffusion transfer
development to form the metallic silver portion on the
non-photosensitive image receiving sheet.
[0267] The mode of the above (1) is an integral black-and-white
development type, and the light-transmitting conductive film such
as the light-transmitting electromagnetic wave-shielding film or
the conductive film having printed wiring is formed on the
light-sensitive material. Developed silver obtained is chemically
developed silver or thermally developed silver, and has high
activity in a subsequent plating or physical development process in
that it is in filament form having a high specific surface
area.
[0268] In the mode of the above (2), in the exposed area the silver
halide grains in the vicinities of the physical development nuclei
are dissolved and deposited on the development nuclei, thereby
forming on the support the light-transmitting conductive film such
as the light-transmitting electromagnetic wave-shielding film or
the light-transmitting conductive film, or the conductive film
having printed wiring. This is also an integral black-and-white
development type. The development action is deposition on the
physical development nuclei, so that activity is high. However,
developed silver is in spherical form having a low specific surface
area.
[0269] In the mode of the above (3), in the unexposed area, the
silver halide grains are dissolved, diffused and deposited on the
development nuclei on the image receiving sheet, thereby forming on
the image receiving sheet the light-transmitting conductive film
such as the light-transmitting electromagnetic wave-shielding film
or the light-transmitting conductive film, or the conductive film
having printed wiring. This is a so-called separate type, and a
mode in which the image receiving sheet is separated from the
light-sensitive material to use.
[0270] In all the modes, either negative development or reversal
development can also be selected. In the case of the diffusion
transfer system, it is also possible to employ a mode in which
negative type development is performed by using an autopositive
type light-sensitive material as the light-sensitive material.
[0271] Chemical development, thermal development, dissolution
physical development and diffusion transfer development as used
herein have the same meanings as the terms ordinarily used in the
industry, and are explained in general textbooks of photographic
chemistry, for example, Shinichi Kikuchi, Photographic Chemistry
(published by Kyoritsu Shuppan Co., Ltd.) and The Theory of
Photographic Process, 4th ed. edited by C. E. K. Mees.
[0272] [Exposure]
[0273] In the production method of the invention, the silver
salt-containing layer provided on the support is exposed. The
exposure can be performed by using electromagnetic waves. Examples
of the electromagnetic waves include light such as visible light
and ultraviolet rays, radiations such as X-rays, and the like.
Further, for the exposure, a light source having wavelength
distribution or a light source having a specific wavelength may be
used. The shape of patterning of irradiated light is a mesh-like
pattern for the production of the electromagnetic wave-shielding
film, and a wiring pattern for the production of the printed
board.
[0274] The above-mentioned exposure includes, for example, scanning
exposure using a cathode ray tube (CRT). The cathode ray tube
exposure apparatus is convenient and compact, and requires low
cost, compared to an apparatuses using a laser. Further, adjustment
of optical axes and colors is also easy. In the cathode ray tube
used for image exposure, various illuminants that emit light in a
certain spectrum region are used as needed. As the illuminant,
there is used, for example, any one of a red illuminant, a green
illuminant and a blue illuminant, or a mixture of two or more
thereof. The spectrum region is not limited to the above-mentioned
red, green and blue regions, and a fluorescent substance that emit
light in a yellow, orange, purple or infrared region is also be
used. In particular, a cathode ray tube in which these illuminants
are mixed to emit white light is often used. Further, an
ultraviolet lamp is also preferred, and the g-line of a mercury
lamp, the i-line of a mercury lamp and the like can also be
utilized.
[0275] Further, in the production method of the invention, the
exposure can be performed by using various laser beams. For
example, in the exposure in the invention, there can be preferably
used a scanning exposure system using monochromatic high density
light such as light emitted by a gas laser, a light emitting diode,
a semiconductor laser or a second harmonic generation (SHG) light
source using a semiconductor laser or a solid-state laser using a
semiconductor laser as an excitation light source and nonlinear
optical crystals in combination. Further, a KrF excimer laser, an
ArF excimer laser, an F2 laser and the like can also be used. In
order to make the system compact and inexpensive, the exposure is
preferably performed by using a semiconductor laser or a second
harmonic generation (SHG) light source using a semiconductor laser
or a solid-state laser and nonlinear optical crystals in
combination. In particular, in order to design a compact,
inexpensive, long-life and highly stable apparatus, the exposure is
preferably performed by using a semiconductor laser.
[0276] As laser light sources, there are preferably used,
specifically, a blue semiconductor laser having a wavelength of 430
to 460 nm (announced by Nichia Corporation at the 48th Lecture
Meeting of Applied Physics-Related Union, March 2001), a green
laser having a wavelength of about 530 nm taken out by converting
the wavelength of a semiconductor laser (oscillation wavelength:
about 1060 nm) using LiNbO.sub.3 SHG crystals having a
waveguide-like reversed domain structure, a red semiconductor laser
having a wavelength of about 685 nm (Hitachi, Type No. HL6738MG), a
red semiconductor laser having a wavelength of about 650 nm
(Hitachi, Type No. HL6501MG) and the like.
[0277] A method for exposing the silver salt-containing layer in
pattern form may be performed by surface exposure utilizing a
photomask or scanning exposure with a laser beam. In this case, the
exposure may be refraction type exposure using a lens or reflection
type exposure using a reflecting mirror, and there can be used
exposure systems such as contact exposure, proximity exposure,
reduction projection exposure and reflecting projection
exposure.
[0278] [Development]
[0279] In the production method of the invention, the silver
salt-containing layer is further developed after the exposure. The
development can be performed by using usual development techniques
used for silver salt photographic films, photographic paper, films
for printing plate making, emulsion masks for photomasks and the
like. Although the developing solution is not particularly limited,
there can also be used a PQ developing solution, an MQ developing
solution, an MAA developing solution and the like. As commercial
products, there can be used, for example, developing solutions such
as CN-16, CR-56, CP45X, FD-3 and Papitol manufactured by Fuji Photo
Film Co., Ltd. and C-41, E-6, RA-4, Dsd-19 and D-72 manufactured by
KODAK, or developing solutions contained in kits thereof. As lith
developing solutions, there can be used D85 manufactured by KODAK,
and the like.
[0280] In the production method of the invention, the
above-mentioned exposure and development are performed, whereby the
patterned metallic silver portion is formed in the exposed area,
and the light-transmitting portion described later is formed in the
unexposed area.
[0281] After the developing treatment, continuously, the sample is
rinsed in water if necessary for a treatment for removing the
binder, to obtain a preferable film with high conductivity.
[0282] The development in the production method of the invention
can include fixing performed for removing a silver salt from an
unexposed area for stabilization. The fixing in the production
method of the invention can be performed by using fixing techniques
used for silver salt photographic films, photographic paper, films
for printing plate making, emulsion masks for photomasks and the
like.
[0283] The developing solution used in the development can contain
an image quality improver for the purpose of improving image
quality. The above-mentioned image quality improvers include, for
example, nitrogen-containing heterocyclic compounds such as
benzotriazole. Further, when the lith developing solution is used,
it is also preferred that particularly, polyethylene glycol is
used.
[0284] The mass of metallic silver contained in the exposed area
after the development is preferably 50% by mass or more, and more
preferably 80% by mass or more, based on the mass of silver
contained in the exposed area before the exposure. When the mass of
silver contained in the exposed area is 50% by mass or more based
on the mass of silver contained in the exposed area before the
exposure, high conductivity is easily obtained, so that such
content is preferred.
[0285] The metallic silver portion contained in the exposed portion
after the developing treatment comprises silver and a
non-conductive polymer, wherein the volume ratio of Ag/the
non-conductive polymer is preferably 2/1 or more, more preferably
3/1 or more.
[0286] Although the gradation after the development in the
invention is not particularly limited, it is preferred to exceed
4.0. When the gradation after the development exceeds 4.0,
conductivity of the conductive metal portion can be increased while
maintaining high transparency of the light-transmitting portion.
Means for increasing the gradation to 4.0 or more include, for
example, the above-mentioned doping with rhodium ions or iridium
ions.
[0287] [Oxidization Treatment]
[0288] In the production method of the invention, the metallic
silver portion after the development is preferably subjected to an
oxidization treatment. For example, when the metal is slightly
deposited on the light-transmitting portion, this metal can be
removed by performing the oxidization treatment to attain a
transparency of the light-transmitting portion of approximately
100%.
[0289] The above-mentioned oxidization treatment includes, for
example, known methods using various oxidizing agents such as
Fe(III) ion treatment. The oxidization treatment can be performed
either after the exposure and development of the silver
salt-containing layer.
[0290] In the invention, the metallic silver portion after the
exposure and development can be further treated with a solution
containing Pd. Pd may be either a bivalent palladium ion or
metallic palladium. This treatment can inhibit the black color of
the metallic silver portion from changing with time.
[0291] In the production method of the invention, the mesh-like
metallic silver portion is formed by subjecting the aforementioned
metal silver portion in which the line width, the open area ratio
and the Ag content are specified is directly formed on the support
by the exposure and development, so that it has a sufficient
surface resistance value. It is therefore unnecessary to further
perform the physical development and/or plating to the metallic
silver portion, thereby imparting conductivity thereto again.
Accordingly, the light-transmitting electromagnetic wave-shielding
film can be produced by a simple process.
[0292] As described above, the light-transmitting electromagnetic
wave shield of the invention can be suitably used as the
light-transmitting electromagnetic wave-shielding film for a plasma
display panel. Accordingly, a plasma display panel formed by using
the light-transmitting electromagnetic wave-shielding film for a
plasma display panel comprising the light-transmitting
electromagnetic wave-shielding film of the invention has high
electromagnetic wave-shielding ability, high contrast and high
lightness, and can be produced at low cost.
[0293] [Reduction Treatment]
[0294] By dipping in an aqueous reducing solution after the
developing treatment, a preferable film with high conductivity can
be obtained. As the aqueous reducing solution, there may be used
aqueous sodium sulfite solution, aqueous hydroquinone solution,
aqueous p-phenylenediamine solution, and aqueous oxalic acid
solution, wherein the aqueous solutions are more preferably
adjusted to pH 10 or more.
[0295] [Smoothing Treatment]
[0296] The invention is characterized in that the smoothing
treatment is performed to the developed metal portion (the
mesh-like metal pattern portion or the wiring metal pattern),
thereby significantly increasing conductivity of the metal portion,
and obtaining the light-transmitting electromagnetic wave-shielding
film simultaneously having high electromagnetic wave-shielding
properties and high translucency, and having the black mesh portion
and the printed board simultaneously having high conductivity and
high insulating properties, and having no pinholes.
[0297] The smoothing treatment can be performed, for example, with
a calender roll unit. The calender roll unit usually comprises a
pair of rolls. As the rolls used for calendering, there are used
plastic rolls such as epoxy, polyimide, polyamide and
polyimideamide rolls and metal rolls. In particular, in the case of
both-side emulsion coating, it is preferred to perform the
treatment with the pair of metal rolls. The line pressure is
preferably 980 N/cm (100 kgf/cm) or more, more preferably 1960 N/cm
(200 kgf/cm) or more, and further more preferably 2940 N/cm (300
kgf/cm) or more.
[0298] The temperature applied to the smoothing treatment
represented by the calender roll treatment is preferably from 10
(no temperature control) to 100.degree. C., and more preferably
ranges from about 10 (no temperature control) to 50.degree. C.,
although it varies depending on the density of scanning or shape of
the mesh-like metal pattern or the wiring metal pattern, and the
binder species.
[0299] As described above, according to the production method of
the invention, the conductive film having high conductivity such as
a surface resistance value of 2.5 .OMEGA./sq or less can be simply
produced at low cost.
Examples
[0300] The invention will be illustrated in greater detail with
reference to the following examples. The materials, amounts used,
proportions, treatment contents, treatment procedures and the like
described in the following examples can be appropriately changed
without departing from the spirit and scope of the invention.
Accordingly, the scope of the invention should not be construed as
being restrictively interpreted by the examples shown below.
Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-3
(Preparation of Emulsion 1-A)
TABLE-US-00001 [0301] Solution 1-1: Water 750 ml Gelatin
(Phthalated Gelatin) 20 g Sodium Chloride 3 g
1,3-Dimethylimidazolidine-2-thione 20 mg Sodium
Benzenethiosulfonate 10 mg Citric Acid 0.7 g Solution 1-2: Water
300 ml Silver Nitrate 150 g Solution 1-3: Water 300 ml Sodium
Chloride 38 g Potassium Bromide 32 g Potassium Hexachloroiridate
(III) 5 ml (0.005% KCl, 20% aqueous solution) Ammonium
Hexachlororhodate 7 ml (0.001% NaCl, 20% aqueous solution)
[0302] Potassium hexachloroiridate (III) (0.005% KCl, 20% aqueous
solution) and ammonium hexachlororhodate (0.001% NaCl, 20% aqueous
solution) used in solution 1-3 were each prepared by dissolving
respective powders in a 20% solution of KCl and a 20% solution of
NaCl, respectively, followed by heating at 40.degree. C. for 120
minutes.
[0303] To solution 1-1 kept at 38.degree. C. and pH 4.5, solution
1-2 and solution 1-3 were each simultaneously added in an amount
corresponding to 90% thereof with stirring over a period of 20
minutes to form 0.16-.mu.m nuclear grains. Subsequently, solution
1-4 and solution 1-5 described below were added over a period of 8
minutes, and the remaining 10 percents of solution 1-2 and solution
1-3 were added over 2 minutes to allow the particles to grow to
0.21 .mu.m. Further, 0.15 g of potassium iodide was added, followed
by ripening for 5 minutes, thus terminating the formation of
grains.
TABLE-US-00002 Solution 1-4: Water 100 ml Silver Nitrate 50 g
Solution 1-5: Water 100 ml Sodium Chloride 13 g Potassium Bromide
11 g Yellow Prussiate of Potash 5 mg
[0304] Then, washing was normally performed by a flocculation
method. Specifically, the temperature was lowered to 35.degree. C.,
and the pH was decreased with sulfuric acid until the silver halide
was sedimented. The pH range was 3.6.+-.0.2. Then, about 3 liters
of a supernatant was removed (the first washing). Further, 3 liters
of distilled water was added, and then, sulfuric acid was added
until the silver halide was sedimented. Then, 3 liters of the
supernatant was removed again (the second washing). The same
operation as the first washing was repeated once more (the third
washing), thus terminating washing and desalting processes. The
emulsion after washing and desalting was adjusted to pH 6.4 and pAg
7.5, and 10 mg of sodium benzenethiosulfonate, 3 mg of sodium
benzenethiosulfmate, 15 mg of sodium thiosulfate and 10 mg of
chloroauric acid were added. Then, chemical sensitization was
performed at 55.degree. C. so as to obtain the optimum sensitivity,
and 100 mg of 1,3,3a,7-tetraazaindene as a stabilizer and 100 mg of
Proxel (trade name, manufactured by ICI Co., Ltd) as a preservative
were added. Finally, a cubic silver iodochlorobromide grain
emulsion containing 70 mol % of silver chloride and 0.08 mol % of
silver iodide and having an average grain size of 0.22 .mu.m and a
coefficient of variation of 9% was obtained (finally, resulting in
pH=6.4, pAg=7.5, electric conductance=40 .mu.S/m,
density=1.2.times.10.sup.3 kg/m.sup.3 and viscosity=60 mPas, as the
emulsion).
[0305] (Preparation of Emulsion 1-B)
[0306] An emulsion prepared under the same conditions as for the
preparation of emulsion 1-A, except for the adjustment of the
amount of gelatin in the first solution to 8 g, was defined as
emulsion 1-B.
(Preparation of Coated Sample)
[0307] To the above-mentioned emulsions I-A and 1-B,
5.7.times.10.sup.-4 mol/mol Ag of sensitizing dye (sd-I) was added
to perform spectral sensitization. Further, 3.4.times.10.sup.-4
mol/mol Ag of KBr and 8.0.times.10.sup.-4 mol/mol Ag of compound
(Cpd-3) were added, followed by followed by thorough stirring.
[0308] Then, 1.2.times.10.sup.-4 mol/mol Ag of 1,3,3
a,7-tetraazaindene, 1.2.times.10.sup.-2mol/mol Ag of hydroquinone,
3.0.times.10 .sup.-4 mol/mol Ag of citric acid, 90 mg/m.sup.2 of
2,4-dichloro-6-hydroxy-1,3,5-triazine sodium salt, 15% by mass
(based on gelatin) of colloidal silica having a particle size of 10
.mu.m, 50 m g/m.sup.2 of aqueous latex (aqL-6), 100 mg/m.sup.2 of a
polyethyl acrylate latex, 100 mg/m.sup.2 of a latex copolymer of
methyl acrylate, sodium 2-acrylamide-2-methylpropanesulfonate and
2-acetoxyethyl methacrylate (mass ratio; 88:5:7), 100 mg/m.sup.2 of
a core-shell type latex (core: styrene/butadiene copolymer (mass
ratio: 37/63), shell: styrene/2-acetoxyethyl acrylate (mass ratio:
84/16), core/shell ratio=50/50) and 4% by mass (based on gelatin)
of compound (Cpd-7) were added, and the pH of the coating solution
was adjusted to 5.6 using citric acid. The coating solution using
emulsion 1-A for an emulsion layer thus prepared are applied onto a
polyethylene terephthalate (PET) film so as to give 10.5 g/m.sup.2
of Ag and 0.94 g/m.sup.2 of gelatin, and then dried and defined as
coated sample 1-A. As the PET film, there was used one previously
subjected to a hydrophilizing treatment.
[0309] A coating solution of an emulsion layer using emulsion 1-B
as prepared in the manner described above was coated on
polyethylene terephthalate (PET) to Ag of 10.5 g/m.sup.2 and
gelatin of 0.33 g/m.sup.2, which was then dried and defined as
coated sample 1-B.
##STR00001##
[0310] In the resulting coated sample 1-A, the Ag/binder volume
ratio of the emulsion layer is 1/0.7, and this corresponds to an
Ag/binder ratio of 1/1 or more that is preferably used in the light
sensitive material for conductive film formation of the
invention.
[0311] In the coated sample 1-B, the volume ratio of Ag/the binder
in the emulsion layer is 4/1, satisfying the condition that the
Ag/a binder ratio should be 2/1 or more for more preferable use in
the light-sensitive material for forming the conductive film of the
invention.
(Exposure and Development)
[0312] The dried coated film was exposed through a grid-like
photomask that can provide a developed silver image of line/space=5
.mu.m/195 .mu.m (a photomask of line/space=195 .mu.m/5 .mu.m
(pitch: 200 .mu.m) in which spaces are in grid form) by using
parallel light whose light source is a high-pressure mercury lamp,
developed with the following developing solution, further developed
by using a fixing solution (trade name: N3X-R for CN16X,
manufactured by Fuji Photo Film Co., Ltd.) and then rinsed with
pure water. Thus, samples 1-A and 1-B different in line width and
open area ratio were obtained. Samples 1-a and 1-b were
obtained.
[0313] 1-A-a and 1-A-b were prepared for the coated sample 1-A,
while 1-B-a and 1-B-b were prepared for the coated sample 1-B.
[0314] The following compounds are contained in 1 liter of the
developing solution.
TABLE-US-00003 Hydroquinone 0.037 mol/L N-Methylaminophenol 0.016
mol/L Sodium metaborate 0.140 mol/L Sodium hydroxide 0.360 mol/L
Sodium bromide 0.031 mol/L Potassium metabisulfite 0.187 mol/L
(Calender Treatment)
[0315] The sample developed as described above was subjected to a
calender treatment. Calender rolls were composed of metal rolls.
The sample was passed between the rolls applying a line pressure of
4900 N/cm (500 kg/cm) thereto, and the surface resistance values
before and after the treatment were measured.
[0316] The sample 1-A-a before the calendar treatment is 1-A-a-1
(Comparative Example 1-1) and 1-A-a after the calendar treatment is
1-A-a-2 (Example 1-1); 1-A-b before the calendar treatment is
1-A-b-1 (Comparative Example 1-2) and 1-A-b after the calendar
treatment is 1-A-b-2 (Example 1-2).
[0317] The sample 1-B before the calendar treatment is 1-B-a-1
(Comparative Example 1-3) and the sample 1-B after the calendar
treatment is 1-B-a-2 (Example 1-3).
[0318] The resulting sample 1-B-a-2 where the volume ratio of
Ag/the non-conductive polymer at the metallic silver portion is
3.1/1 and which is at a density of 8.5 g/cm.sup.3 and a thickness
of 1.2 .mu.m, is preferably used for the conductive film of the
invention, because the sample satisfies the conditions that the
volume ratio of Ag/the non-conductive polymer at the metallic
silver portion should be 3/1 or more and the thickness should be
0.5 .mu.m to 5 .mu.m.
[0319] (Blackening Treatment)
[0320] The transparent film with a mesh-like silver image formed
thereon was electrically plated in a bath of a blackening plating
solution of the following composition, using carbon as an anion
electrode.
[0321] The plating solution for the blackening plating treatment is
as follows.
TABLE-US-00004 Composition of blackening solution Nickel
sulfate.cndot.6 hydrate salt 120 g Ammonium thiocyanate 17 g Zinc
sulfate.cndot.7 hydrate salt 28 g Sodium sulfate 16 g Addition of
Water (in total of one liter) pH 5.0 (pH adjusted with sulfuric
acid and sodium hydroxide)
[0322] Plating Conditions
[0323] Bath temperature: about 30.degree. C.
[0324] Time period: 20 seconds
[0325] Cation electrode current density: 0.1 to 0.2 A/dm2 (0.03 A
current for the whole cation electrode (35 mm.times.12 cm))
[0326] An blackening-treated sample from the sample 1-B-a-2
(Example 1-3) is defined as 1-B-a-3 (Example 1-4).
Comparative Examples 1-4 to 1-7
(Preparation of Samples for Comparison)
[0327] For the comparison with a technique that is highest in
conductivity and high in light transmitting properties, of those
known at present, a metal mesh described in JP-A-10-41682 was
prepared as a representative of the "etching-processed copper mesh
utilizing photolithography" described in the section of "Background
Art" described above, and taken as Comparative Example 1-4.
[0328] This sample was prepared in the same manner as in the
example of JP-A-10-41682.
[0329] In order to allow the mesh shape (line width and pitch) to
agree with that of the sample of the invention, the same 200-.mu.m
pitch photomask as described above was utilized.
[0330] Further, a metal mesh described in JP-B-42-23746 was
prepared as a representative of a silver salt diffusion transfer
process of depositing silver on physical development nuclei, which
is the "conductive silver forming method utilizing silver salt"
described in the section of "Background Art" described above, and
taken as Comparative Example 1-5. This sample was prepared by
coating a hydrophilized transparent TAG (triacetyl cellulose)
support with a physical development nucleus layer and a
photosensitive layer, giving exposure through a mesh-like photomask
having a pitch of 200 .mu.m and performing development by a DTR
method, in the same manner as described in Example 3 of
JP-B-42-23746.
[0331] Furthermore, a metal mesh described in JP-A-2000-13088 was
prepared as a representative of the "silver paste-printed mesh"
described in the section of "Background Art" described above. For
this metal mesh, samples of Comparative Examples 1-6 and 1-7
different in open area ratio were prepared.
(Evaluation)
[0332] For the samples of the invention each having the conductive
metal portion and the light-transmitting portion and the samples
for comparison thus obtained, the line width of the conductive
metal portion was measured to determine the open area ratio, and
further, the surface resistance value was measured. In each
measurement, an optical microscope, a scanning electron microscope
and a low resistivity meter were used.
[0333] Further, the color of the metal portion of the mesh was
visually observed. Black was taken as "good", and brown to gray was
taken as "poor". Furthermore, as for the number of processes in the
production method, one having 5 or less processes was evaluated as
"good", and one having 6 or more processes was evaluated as
"poor".
[0334] The film strength was evaluated as follows.
[0335] Scratching the face with the mesh metal part formed thereon
using a 0.1-mm-.phi. sapphire needle at a speed of 1 cm/second. By
changing the load on the sapphire needle from 0 to 100 g, the load
at which scratches reach the base is used as the marker of the film
strength. In Table 1-1, "Good" indicates the load at which
scratches occur is 80 g or more, "Fair" indicates the load at which
scratches occur is 50 g, and "Poor" indicates the load at which
scratches occur is 20 g.
[0336] The results of evaluation as well as the data of the samples
for comparison are shown in Table 1-1.
TABLE-US-00005 TABLE 1-1 Open Line Area Surface Width Ratio
Resistance Film Sample (.mu.m) (%) (.OMEGA./sq) Process Color
Strength Remark Comparative Sample 1-A-a-1 15 86 2.5 Good Good Poor
Comparison Example 1-1 (Not calendered) Example 1-1 Sample 1-A-a-2
15 86 1.0 Good Good Good Invention (Calendered) Comparative Sample
1-A-b-1 9 91 3.5 Good Good Poor Comparison Example 1-2 (Not
calendered) Example 1-2 Sample 1-A-b-2 9 91 1.5 Good Good Good
Invention (Calendered) Comparative Sample 1-B-a-1 15 86 2.0 Good
Good Poor Comparison Example 1-3 (Not calendered) Example 1-3
Sample 1-B-a-2 15 86 0.5 Good Good Fair Invention (Calendered)
Example 1-4 Sample 1-B-a-3 15 86 0.5 Good Good Good Invention
(Blackening treatment) Comparative JP-A-10-41682 12 88 0.1 Poor
Poor Good Comparison Example 1-4 Supplementary Etching examination
Comparative JP-B-42-23746 15 86 90 Good Poor Fair Comparison
Example 1-5 Supplementary Silver examination salt Comparative
JP-A-2000-13088 20 81 5 Good Good Fair Comparison Example 1-6
Supplementary Pitch 200 .mu.m Silver examination Comparative 20 87
9 Good Good Fair paste Example 1-7 Pitch 200 .mu.m
[0337] As seen from Table 1-1, the etching-processed copper mesh of
Comparative Example 1-4 was brown in mesh color, and the number of
processes was also many. Further, for the mesh utilizing the silver
salt of Comparative Example 1-5, the surface resistance value was
high, and the electromagnetic wave-shielding ability was
insufficient. Furthermore, for the silver paste-printed mesh of
Comparative Example 1-6, the open area ratio was low because of its
thick line width. In addition, for such a mesh, it is possible to
increase the open area ratio by widening the pitch as the silver
paste-printed mesh of Comparative Example 1-7. However, in that
case, the surface resistance value increased.
[0338] In contrast, the samples of the invention (Examples 1-1 and
1-2) do not have problems observed in the above-mentioned
Comparative Examples. The line width is thin, the open area ratio
is high, and the surface resistance value is low (the
electromagnetic wave-shielding ability is high). Further, the metal
portion of the mesh of the inventive sample (Example 1-4) is black,
so that an adverse effect (a reduction in contrast) to images of a
display can be avoided. Furthermore, the number of processes in the
production was small.
[0339] It is further demonstrated that the inventive sample has
high film strength involving less break or peel during handling so
the inventive sample has high quality reliability.
Working Example 2-1
[0340] Working example 2-1 for evaluating the properties (e.g.,
surface resistance, film strength) of the fine line structure part
formed on a support is described below.
Examples 2-1 to 2-14 and Comparative Examples 2-1 to 2-7
(Preparation of Emulsion 2-A)
TABLE-US-00006 [0341] Solution 2-1: Water 750 ml Gelatin
(phthalated gelatin) 20 g Sodium chloride 3 g
1,3-Dimethylimidazolidine-2-thione 20 mg Sodium
benzenethiosulfonate 10 mg Citric acid 0.7 g Solution 2-2: Water
300 ml Silver nitrate 150 g Solution 2-3: Water 300 ml Sodium
chloride 38 g Potassium bromide 32 g Potassium
hexachloroiridate(III) (0.005% KCl, 20% 5 ml aqueous solution)
Ammonium hexachlororhodate (0.001% NaCl, 20% 7 ml aqueous
solution)
[0342] Potassium hexachloroiridate(III) (0.005% KCl, 20% aqueous
solution) and ammonium hexachlororhodate (0.001% NaCl, 20% aqueous
solution) used in Solution 2-3 each was prepared by dissolving the
complex powder in a 20% aqueous solution of KCl or a 20% aqueous
solution of NaCl and heating the mixture at 40.degree. C. for 120
minutes.
[0343] To Solution 2-1 kept at 38.degree. C. and pH 4.5, Solution
2-2 and Solution 2-3 each in an amount corresponding to 90% were
simultaneously added with stirring over 20 minutes to form
0.16-.mu.m core grains. Subsequently, Solution 2-4 and Solution 2-5
shown below were added over 8 minutes, and the remainings of
Solution 2-2 and Solution 2-3 each in an amount corresponding to
10% were added over 2 minutes, thereby growing the grains to 0.21
.mu.m. Furthermore, 0.15 g of potassium iodide was added and after
ripening for 5 minutes, the grain formation was terminated.
TABLE-US-00007 Solution 2-4: Water 100 ml Silver nitrate 50 g
Solution 2-5: Water 100 ml Sodium chloride 13 g Potassium bromide
11 g Yellow prussiate of potash 5 mg
[0344] Thereafter, water washing was performed by a flocculation
method in the usual manner. Specifically, the temperature was
lowered to 35.degree. C., and the pH was decreased with sulfuric
acid until the silver halide was precipitated (the pH range was
3.6.+-.0.2).
[0345] Subsequently, about 3 liters of the supernatant was removed
(first washing). After adding 3 liters of distilled water, sulfuric
acid was added until the silver halide was precipitated. Again, 3
liters of the supernatant was removed (second washing). The same
operation as the second washing was repeated once more (third
washing), and the washing and desalting processes were
terminated.
[0346] The emulsion after washing and desalting was adjusted to pH
6.4 and pAg 7.5 and then subjected to chemical sensitization at
55.degree. C. by adding 10 mg of sodium benzenethiosulfonate, 3 mg
of sodium benzenethiosulfinate, 15 mg of sodium thiosulfate and 10
mg of chloroauric acid so as to obtain optimum sensitivity, and 100
mg of 1,3,3a,7-tetrazaindene as a stabilizer and 100 mg of Proxel
(trade name, produced by ICI Co., Ltd.) as a preservative were
added. Finally, a cubic silver iodochlorobromide grain emulsion
containing 70 mol % of silver chloride and 0.08 mol % of silver
iodide and having an average grain size of 0.22 .mu.m and a
coefficient of variation of 9% was obtained. In the final emulsion
obtained, pH-6.4, pAg=7.5, electric conductance=40 .mu.S/m,
density=1.2.times.10.sup.3 kg/m.sup.3 and viscosity=60 mPas.
(Preparation of Emulsion 2-B)
[0347] The emulsion prepared under the same conditions as in
Preparation of Emulsion 2-A except for changing the amount of
gelatin in Solution 2-1 to 8 g was designated as Emulsion 2-B.
(Production of Coated Sample)
[0348] To Emulsions 2-A and 2-B prepared above, 5.7.times.10.sup.-4
mol/mol-Ag of Sensitizing Dye (sd-1) was added to effect spectral
sensitization. Furthermore, 3.4.times.10.sup.-4 mol/mol-Ag of KBr
and 8.0.times.10.sup.-4 mol/mol-Ag of Compound (Cpd-3) were added
and thoroughly mixed.
[0349] Subsequently, 1.2.times.10.sup.-4 mol/mol-Ag of
1,3,3a,7-tetrazaindene, 1.2.times.10.sup.-2 mol/mol-Ag of
hydroquinone, 3.0.times.10.sup.-4 mol/mol-Ag of citric acid, 90
mg/m.sup.2 of 2,4-dichloro-6-hydroxy-1,3,5-triazine sodium salt, 15
wt % (based on gelatin) of colloidal silica having a particle
diameter of 10 .mu.m, 50 mg/m.sup.2 of Aqueous Latex (aqL-6), 100
mg/m.sup.2 of a polyethyl acrylate latex, 100 mg/m.sup.2 of a latex
copolymer of methyl acrylate, sodium
2-acrylamide-2-methylpropanesulfonate and 2-acetoxyethyl
methacrylate (weight ratio: 88:5:7), 100 mg/m.sup.2 of a core-shell
type latex (core: styrene/butadiene copolymer (weight ratio:
37/63), shell: styrene/2-acetoxyethyl acrylate (weight ratio:
84/16), core/shell ratio=50/50) and 4 wt % (based on gelatin) of
Compound (Cpd-7) were added, and the thus-prepared coating solution
was adjusted to pH 5.6 with citric acid.
[0350] The coating solution for emulsion layer prepared above by
using Emulsion 2-A was coated on polyethylene terephthalate (PET)
to give coverages of 10.5 g/m.sup.2 of Ag and 0.94 g/m.sup.2 of
gelatin and then dried, and this sample was designated as Coated
Sample 2-A.
[0351] A coating solution for emulsion layer prepared in the same
manner as above by using Emulsion 2-B was coated on polyethylene
terephthalate (PET) to give coverages of 10.5 g/m.sup.2 of Ag and
0.33 g/m.sup.2 of gelatin and then dried, and this sample was
designated as Coated Sample 2-B.
[0352] The PET used was previously subjected to a surface
hydrophilizing treatment.
##STR00002##
[0353] In Coated Sample 2-A obtained, the Ag/binder volume ratio
(silver/GEL ratio (by volume)) of the emulsion layer was 1/0.7, and
this satisfies the Ag/binder ratio of 1/1 or more that is
preferably used in the light-sensitive material for forming the
conductive film of the present invention (see, Examples 2-1 and 2-2
and Comparative Examples 2-1 and 2-2).
[0354] In Coated Sample 2-B, the Ag/binder volume ratio (silver/GEL
ratio (by volume)) of the emulsion layer is 4/1, and this satisfies
the Ag/binder ratio of 2/1 or more that is more preferably used in
the light-sensitive material for forming the conductive film of the
present invention (see, Examples 2-3 and 2-4 and Comparative
Example 2-3). Also, samples of Examples 2-5 to 2-11 were prepared
by changing the amount of gelatin.
(Exposure and Development)
[0355] The coated film after drying was exposed through a grid-like
photomask of line/space=195 .mu.m/5 .mu.m (pitch: 200 .mu.m) having
spaces in grid pattern and giving a developed silver image of
line/space=5 .mu.m/195 .mu.m, by using parallel light of which
light source is a high-pressure mercury lamp, developed with the
following developer, further developed using a fixing solution
(trade name: N3X-R for CN16X, produced by Fujifilm Corp.), and then
rinsed with pure water. In this way, samples 2-a and 2-b differing
in the line width and open area ratio were obtained.
[0356] Those produced using Coated Sample 2-A were designated as
2-A-a (see, Comparative Example 2-1 and Example 2-1) and 2-A-b
(see, Comparative Example 2-2 and Example 2-2), and those produced
using Coated Sample 2-B were designated as 2-B-a (see, Comparative
Example 2-3 and Examples 2-3 and 2-4) and 2-B-b (Example 2-5).
Samples by entire surface exposure were also produced (see,
Comparative Example 2-7 and Examples 2-13 and 2-14).
[Composition of Developer]
[0357] The following compounds are contained in 1 liter of the
developer.
TABLE-US-00008 Hydroquinone 0.037 mol/L N-Methylaminophenol 0.016
mol/L Sodium metaborate 0.140 mol/L Sodium hydroxide 0.360 mol/L
Sodium bromide 0.031 mol/L Potassium metabisulfite 0.187 mol/L
(Calender Treatment)
[0358] The samples developed as above were subjected to a calender
treatment. The calender roll was composed of a metal roll (iron
core+bard chromium plating, roll diameter: 250 mm). The sample was
passed between the rolls under a line pressure of 1,960 N/cm (200
kgf/cm; 700 kgf/cm.sup.2 in terms of surface pressure) to 7,840
N/cm (800 kgf/cm; 1,850 kgf/cm.sup.2 in terms of surface pressure),
and the surface resistivity (.OMEGA./sq) before and after the
treatment was measured. In the case of this working example, the
line pressure of 100 kgf/cm is 417 kgf/cm.sup.2 in terms of surface
pressure, the line pressure of 200 kgf/cm is 700 kgf/cm.sup.2 in
terms of surface pressure, the line pressure of 300 kgf/cm is 936
kgf/cm.sup.2 in terms of surface pressure, and the line pressure of
600 kgf/cm is 1,519 kgf/cm.sup.2 in terms of surface pressure.
[0359] As for Sample 2-A-a, the sample before calender treatment
was designated as 2-A-a-1 (Comparative Example 2-1) and the sample
after the treatment was designated as 2-A-a-2 (Example 2-1). Also,
as for Sample 2-A-b, the sample before calender treatment was
designated as 2-A-b-1 (Comparative Example 2-2) and the sample
after the treatment was designated as 2-A-b-2 (Example 2-2).
[0360] As for Sample 2-B, the sample before calender treatment was
designated as 2-B-a-1 (Comparative Example 2-3), and the sample
after the treatment was designated as 2-B-a-2 (Example 2-3).
[0361] In Sample 2-B-a-2 (Example 2-3) obtained, the volume ratio
of Ag/non-conductive polymer in the metallic silver part was 3.1/1,
the density was 8.5 g/cm.sup.3 and the thickness was 1.2 .mu.m, and
this sample satisfies the conditions that the volume ratio of
Ag/non-conductive polymer in the metallic silver portion is 3/1 or
more and the thickness is 0.5 to 5 .mu.m, which are preferably used
in the conductive film of the present invention.
(Blackening Treatment)
[0362] The transparent film having formed thereon a mesh-like
silver image was electroplated in a blackening plating solution
bath having the following composition by using carbon for the anode
electrode.
[0363] The plating solution for the blackening plating treatment is
as follows.
[Composition of Blackening Solution]
TABLE-US-00009 [0364] Nickel sulfate hexahydrate salt 120 g
Ammonium thiocyanate 17 g Zinc sulfate heptahydrate salt 28 g
Sodium sulfate 16 g Pure water to make 1 L pH 5.0 (pH adjusted)
with sulfuric acid and sodium hydroxide
[Plating Conditions]
[0365] Bath temperature: about 30.degree. C.
[0366] Time: 20 seconds
[0367] Cathode current density: 0.1 to 0.2 A/dm.sup.2 (a current of
0.03 A for the entire cathode (35 mm.times.12 cm))
[0368] As for Sample 2-B-a-2 (Example 2-3), the sample after the
blackening treatment above was designated as 2-B-a-3 (Example
2-4).
Comparative Examples 2-4 to 2-6
[0369] For the purpose of comparison with a technique assured of
highest conductivity and high light transparency out of those known
at present, a metal mesh described in JP-A-10-41682 was produced as
representative of the "etching-processed copper mesh utilizing
photolithography" in "Background Art" above and was taken as the
sample of Comparative Example 2-4.
[0370] This sample (Comparative Example 2-4) was produced in the
same manner as in Examples of JP-A-10-41682.
[0371] In order to allow the mesh shape, line width and pitch to
agree with those of the sample of the present invention, a
photomask having the same pitch of 200 .mu.m as above was
utilized.
[0372] Also, a metal mesh described in JP-A-2000-13088 was produced
as representative of the "silver paste-printed mesh" in "Background
Art" above, whereby samples of Comparative Examples 2-5 and 2-6
differing in the open area ratio were produced.
[Evaluation]
[0373] The thus-obtained samples of the present invention having a
conductive metal portion and a light-transmitting portion and
samples of Comparative Examples each was measured for line width of
the conductive metal portion to determine the open area ratio and
further, measured for surface resistivity (.OMEGA./sq). In each
measurement, an optical microscope, a scanning electron microscope
and a low resistivity meter were used.
[0374] Also, the color of the metal portion of the mesh was
evaluated with an eye, and the mesh was rated "good" for black and
rated "bad" for brown to gray. As for the number of steps in the
production method, the method having 5 or less steps was rated
"good", and the method requiring more than 5 steps was rated
"bad".
[0375] Furthermore, the film strength was evaluated as follows.
[0376] The surface having formed thereon a mesh metal portion was
scratched using a 0.1-mm.phi. sapphire needle at a speed of 1
cm/second. By changing the load on the sapphire needle from 0 to
100 g, the load at which the scratch reached the base was made
indicative of the film strength.
[0377] Good: The load at which generation of scratches starts is 80
g or more.
[0378] Fair: The load at which generation of scratches starts is
from 50 g to less than 80 g.
[0379] Bad: The load at which generation of scratches starts is
from 20 g to less than 50 g.
[0380] The evaluation results are shown in Table 2-1 together with
the data of each sample.
TABLE-US-00010 TABLE 2-1 Calender Calender Silver/ Name of Pressure
After Pressure After Blackening GEL Ratio Density, Sample
Development Fixing Treatment (vol) g/cm.sup.3 Remarks Comparative
2-A-a-1 none none -- 1/0.7 -- Comparison Example 2-1 Example 2-1
2-A-a-2 none 500 kg/cm -- 1/0.7 -- Invention comparative 2-A-b-1
none none -- 1/0.7 -- Comparison Example 2-2 Example 2-2 2-A-b-2
none 500 kg/cm -- 1/0.7 -- Invention Comparative 2-B-a-1 none none
-- 4/1 -- Comparison Example 2-3 Example 2-3 2-B-a-2 none 500 kg/cm
-- 4/1 8.5 Invention Example 2-4 2-B-a-3 none 500 kg/cm treated 4/1
8.5 Invention Comparative none JP-A-10-41682, -- -- -- Comparison
Example 2-4 additional test (etching) Comparative none
JP-A-2000-13088, -- -- -- Comparison Example 2-5 additional test
(silver paste Comparative printing) Example 2-6 Example 2-5 2-B-b-1
none 400 kg/cm -- 4/1 -- Invention Example 2-6 none 400 kg/cm --
3.06/1 -- Invention Example 2-7 none 400 kg/cm -- 2.48/1 --
Invention Example 2-8 none 400 kg/cm -- 2.08/1 -- Invention Example
2-9 none 400 kg/cm -- 1.54/1 -- Invention Example 2-10 none 400
kg/cm -- 1.28/1 -- Invention Example 2-11 none 400 kg/cm -- 0.95/1
-- Invention Comparative none none -- 4/1 -- Comparison Example 2-7
Example 2-13 none 210 kg/cm -- 4/1 -- Invention Example 2-14 210
kg/cm 210 kg/cm -- 4/1 -- Invention Surface Thickness, Line Width,
Pitch, Open Area Resistance, Number Film .mu.m .mu.m .mu.m Ratio, %
.OMEGA./sq of Steps Color Strength Remarks Comparative -- 15 200 86
2.5 Good Good Bad Comparison Example 2-1 Example 2-1 -- 15 200 86 1
Good Good Good Invention comparative -- 9 200 91 3.5 Good Good Bad
Comparison Example 2-2 Example 2-2 -- 9 200 91 1.5 Good Good Good
Invention Comparative -- 15 200 86 2 Good Good Bad Comparison
Example 2-3 Example 2-3 1.2 15 200 86 0.5 Good Good Fair Invention
Example 2-4 1.2 15 200 86 0.5 Good Good Good Invention Comparative
-- 12 200 88 0.1 Bad Bad Good Comparison Example 2-4 (etching)
Comparative -- 20 200 81 5 Good Good Fair Comparison Example 2-5
(pitch: 200 .mu.m) (silver paste Comparative 20 300 87 9 Good Good
Fair printing) Example 2-6 (pitch: 300 .mu.m) Example 2-5 -- 16.5
300 89 1.8 Good Good Fair Invention Example 2-6 -- 16.5 300 89 1.7
Good Good Good Invention Example 2-7 -- 16.5 300 89 1.7 Good Good
Good Invention Example 2-8 -- 16.5 300 89 1.6 Good Good Good
Invention Example 2-9 -- 16.5 300 89 2.7 Good Good Good Invention
Example 2-10 -- 16.5 300 89 2.8 Good Good Good Invention Example
2-11 -- 16.5 300 89 6.0 Good Good Good Invention Comparative --
entire surface -- -- 0.29 Good Good Bad Comparison Example 2-7
Example 2-13 -- entire surface -- -- 0.14 Good Good Fair Invention
Example 2-14 -- entire surface -- -- 0.08 Good Good Fair
Invention
[0381] As seen from Table 2-1, in the etching-processed copper mesh
of Comparative Example 2-4, the mesh color is brown and the number
of steps is large. In the copper paste-printed mesh of Comparative
Example 2-5, the open area ratio is low because of its thick line
width. In this case, as seen from Comparative Example 2-6, the open
area ratio can be increased by widening the pitch but there arises
a new problem that the surface resistivity increases.
[0382] On the other hand, in Examples 2-1 and 2-2, problems
incurred in Comparative Examples above are not caused, the line
width is thin, widening from the original line width can be hardly
recognized, the open area ratio is large, and the surface
resistivity is low to give high electromagnetic wave-shielding
ability.
[0383] In Example 2-4 which is a more preferred embodiment, the
metal portion of the mesh is black, so that an adverse effect
(reduction in contrast) on the display image can be avoided. Also,
the number of steps in the production is small.
[0384] Moreover, it is seen that in Examples 2-1 to 2-4, the film
strength is high to less cause chipping or separation of the mesh
portion during handling and the reliability in view of quality is
high.
[0385] In Examples 2-5 to 2-8 where the amount of gelatin is
changed, the line width is slightly larger than that in Examples
2-1 to 2-4. However, since the surface resistivity is low even when
the open area ratio is increased by widening the pitch, a larger
opening area ratio than that in Examples 2-1 to 2-4 can be taken.
Also, the film strength is large and the reliability is high.
[0386] In Comparative Example 2-7 by entire surface exposure, the
surface resistivity is low and good, but the film strength is low
and there is a problem in the reliability. On the other hand, in
Examples 2-13 and 2-14 by entire surface exposure, the surface
resistivity is lower than that in Comparative Example 2-7 and
moreover, the film strength is high to give satisfactory
reliability.
[0387] Incidentally, in Examples 2-9 to 2.-11, the surface
resistivity is higher than 2.5 (.OMEGA./sq) and the conductivity is
insufficient, but the film strength is high and satisfactory
reliability is achieved.
Working Example 2-2
[0388] Out of Examples 2-1 to 2-14 shown in Table 2-1, the surface
resistivity in Example 2-14 where a calender treatment was
performed after development and a calender treatment was further
performed also after fixing is 0.08 (.OMEGA./sq) and shows a lowest
value.
[0389] Therefore, the relationship between line pressure and
surface resistivity in the calender treatment after development and
the calender treatment after fixing was examined. FIG. 1 shows the
results obtained.
[0390] The same sample as Sample 2-B-a-2 (see, Example 2-3) was
used. The sample was exposed and developed in the same manner as
above and then washed with pure water for 1 minute, followed by
drying at 40.degree. C. Thereafter, a calender treatment after
development was performed. Furthermore, the sample was subject to
fixing using a fixing solution (trade name: N3X-R for CN16X,
produced by Fujifilm Corp.), washing with pure water for 2 minutes
and drying, and then, a calender treatment after fixing was
performed.
[0391] Two kinds of calender rolls for use in the calender
treatment were prepared. One is a first calender roll by a
combination of a metal roll with the surface being embossed and a
metal roll with the surface being mirror-finished, and another is a
second calender roll by a combination of a metal roll with the
surface being mirror-finished and a resin-made roll.
[0392] The change in surface resistivity when performing the
calender treatments (after development and after fixing) with the
first calender roll by varying the line pressure is shown by
diamond plots, and the change in surface resistivity when
performing the calender treatments (after development and after
fixing) with the second calender roll by varying the line pressure
is shown by square plots.
[0393] It is seen from FIG. 1 that in the case of performing a
calender treatment after fixing as well as after development, a
surface resistivity of 1.8 (.OMEGA./sq) or less can be obtained
with a line pressure of 200 (kgf/cm) or more almost independently
of the type of the calender roll. Also, slight increase in the
surface resistivity is observed when the line pressure exceeds 700
(kgf/cm), and this reveals that the upper limit is preferably 700
(kgf/cm) or less.
Working Example 2-3
[0394] Working example 2-3 for evaluating the characteristics
(e.g., transmittance, volume resistance, surface resistance,
flexibility) of a transparent conductive film sample is described
below.
1. Production of Support Carrying Fine Line Structure Part
(Preparation of Emulsion)
[0395] The preparation was the same as that of Emulsion 2-A of the
working example 2-1, and redundant description thereof is omitted
here.
(Production of Coated Sample)
[0396] The production was the same as that of Coated Sample 2-A
using Emulsion 2-A, similarly to the matters described in the
working example 2-1, and redundant description thereof is omitted
here.
[0397] In the coated samples obtained, the Ag/binder volume ratio
of the emulsion layer was 1/0.7, satisfying the Ag/binder volume
ratio of 1/4 or more which is preferably used in the present
invention.
(Exposure and Development)
[0398] Subsequently, the coated film after drying was exposed
through a grid-like photomask capable of giving a developed silver
image of line/space=10 .mu.m/300 .mu.m, by using parallel light of
which light source is a high-pressure mercury lamp, developed with
the following developer, further developed using a fixing solution
(trade name: N3X-R for CN16X, produced by Fujifilm Corp.), and then
rinsed with pure water.
[0399] The light-sensitive material exposed and developed using the
treating agents above was processed by development at 25.degree. C.
for 20 seconds, fixing at 25.degree. C. for 20 seconds and washing
with running water (5 L/min) for 20 seconds, in order of
development, washing, drying, consolidation treatment, fixing,
washing, drying and consolidation treatment. In the consolidation
treatment, a calender roll apparatus having mounted therein metal
rolls was used and the sample was passed between rolls by applying
a line pressure of 3,920 N/cm (400 kgf/cm).
2. Coating of Transparent Conductive Film
[0400] On the fine line structure part formed as above, a
transparent conductive film comprising the following conductive
polymer was coated as shown in Table 2-1 by a bar coater while
varying the coated amount to produce transparent conductive film
samples (Examples 2-21 to 2-23). Also, the transparent conductive
film was coated on a PET base not having a fine line structure
part, to the same thickness as in Examples 2-21 to 2-23 to produce
film samples of Comparative Examples 2-21 to 2-23. The conductive
polymer used was Conductive Polymer Baytron PEDOT
(polyethylene-dioxythiophene) produced by TA Chemical Co. The
drying was performed by natural drying at room temperature.
[0401] Similarly, a sample only with the fine line structure part
and a sample using an ITO film were prepared as samples of
Comparative Examples 2-24 and 2-25, respectively.
3. Production of Electroluminescent Device
[0402] The transparent conductive film samples prepared as above
(Examples 2-21 to 2-23 and Comparative Examples 2-21 to 2-25) each
was incorporated into an inorganic dispersion-type EL
(electroluminescent) device as follows, and a light emission test
was performed.
[0403] A reflective insulating layer containing a pigment having an
average particle size of 0.03 .mu.m and a light-emitting layer
comprising a phosphor particle of 50 to 60 .mu.m were coated on an
aluminum sheet working out to a backside electrode and dried at
110.degree. C. for 1 hour by using a hot-air dryer.
[0404] Thereafter, the transparent conductive film sample was
placed on the fluorescent material layer and dielectric layer
surface of the backside electrode and heat-press-bonded to produce
an EL device. The EL device was heat-press-bonded with two
water-absorbing sheets composed of nylon 6 by using two
moisture-proof films each interposed therebetween. The size of the
EL device was 3 cm.times.5 cm or A4 size.
4. Evaluation
(Surface Resistance/Transmittance of Sample)
[0405] The samples of Examples 2-21 to 2-23 and Comparative
Examples 2-21 to 2-25 each was measured for surface resistance and
transmittance to light at a wavelength of 550 nm.
(Brightness of Sample)
[0406] Using the sample of 3 cm.times.5 cm, the initial brightness
when driving it at a peak voltage of 100 V and a frequency of 1 kHz
was evaluated.
(Evaluation of Flexibility)
[0407] The samples (Examples 2-21 to 2-23 and Comparative Examples
2-21 to 2-25) in the flexing test above were determined for the
increase rate K of surface resistance. Assuming that the surface
resistance of the sample before flexing test is R1 and the surface
resistance of the sample after flexing test is R2, the increase
rate K of surface resistance was determined according to the
following formula:
K=R2/R1
[0408] In the flexing test, as shown in FIG. 2, the sample 34
(samples of Examples 2-21 to 2-23 and Comparative Examples 2-21 to
2-25) was caught on a roller 32 of 4 min in diameter rotatably
fixed to base stands 30, and the sample 34 was flexed 100 times by
repeatedly performing a step of rotating the roller 32 while
pulling one end part 34a of the sample 34 at a tension of 28.6 (kg)
per 1 m of the width to flex the sample 34, and a step of rotating
the roller 32 while pulling another end part 34b of the sample 34
at a tension of 28.6 (kg) per 1 m of the width to flex the sample
34.
[0409] Rating was "good" when the increase rate K of surface
resistance is 1.2 or less, "fair" when from 1.2 to 10, and "bad"
when 10 or more.
(Result 1)
[0410] The evaluation results of the samples of Examples 2-21 to
2-23 and Comparative Examples 2-21 to 2-25 regarding transmittance,
surface resistance of fine line structure part, surface resistance
of transparent conductive film, strength, and flexibility are shown
in Table 2-2.
TABLE-US-00011 TABLE 2-2 Volume Resistance Surface Resistance
(.OMEGA. cm) (.OMEGA./sq) Fine Line Transparent Fine Line
Transparent Transparent Conductive Transmittance Structure
Conductive Structure Conductive Film Sample (breakdown) (%) Part
Film Part Film Brightness Flexibility Example 2-21 fine line
structure part + 63 6 .times. 10.sup.-6 5 1 3.8 .times. 10.sup.2
16801 Good transparent conductive film Example 2-22 fine line
structure part + 66 6 .times. 10.sup.-6 5 1 1.4 .times. 10.sup.4
17610 Good transparent conductive film Example 2-23 fine line
structure part + 75 6 .times. 10.sup.-6 5 1 1.6 .times. 10.sup.5
24400 Good transparent conductive film Comparative only transparent
conductive 79 -- 5 -- 3.8 .times. 10.sup.2 29107 Good Example 2-21
film Comparative only transparent conductive 81 -- 5 -- 1.4 .times.
10.sup.4 19382 Good Example 2-22 film Comparative only transparent
conductive 90 -- 5 -- 1.6 .times. 10.sup.5 0 Good Example 2-23 film
Comparative only fine line structure part 90 6 .times. 10.sup.-6 --
1 -- 9049 Good Example 2-24 Comparative ITO film 91 -- 4 .times.
10.sup.4 -- .sup. 3.8 .times. 10.sup.-2 32268 Bad Example 2-25
[0411] As seen from the evaluation results above, in Comparative
Example 2-24 (only fine line structure part), the surface
resistance was lower than that in Comparative Example 2-25 (only
ITO film), but, as shown in FIG. 3A, light was emitted only in the
vicinity of fine lines and due to no light emission in the open
areas, the brightness became extremely low. On the other hand, in
Examples 2-21 to 2-23 where a transparent conductive film was
applied to the fine line structure part, as shown in FIG. 3B, light
emission over the entire surface was confirmed. Also, when a
transparent conductive film with a surface resistance of 10.sup.5
.OMEGA./sq was used, light was not emitted in Comparative Example
2-23, but light emission over the entire surface was confirmed in
Example 2-23.
Working Example 2-4
[0412] With respect to the A4-size samples (Example 2-23 and
Comparative Examples 2-21, 2-24 and 2-25) out of the samples
produced above, a take-out electrode was provided, as shown in FIG.
4, on the bus bar formed of an Ag paste and after measuring the
brightness by changing the distance from the take-out electrode
under driving at a peak voltage of 50 V and a frequency of 1.4 kHz,
the brightness ratio based on the brightness (=1) in the vicinity
of the take-out electrode (reference point) was determined. The
reference point was placed at 10 mm in terms of the shortest
distance from the bus bar, and the measurement points were placed
at 50 mm, 100 mm, 150 mm, 200 mm and 250 mm in terms of the
shortest distance from the bus bar.
[0413] FIG. 5 shows the measurement results. As seen from the
results, in Comparative Example 2-21 with only a transparent
conductive film, the brightness is decreased as the distance from
the take-out electrode increases. In Comparative Example 2-24 (only
fine line structure part), the brightness is scarcely decreased and
nearly constant irrespective of the distance from the take-out
electrode, but as described above, there is a problem in
Comparative Example 2-24 that surface emission is not obtained as
shown in FIG. 3A. In Comparative Example 2-25 using an ITO film,
the brightness is scarcely decreased until the measurement point of
200 mm, but at the measurement point of 250 mm, the brightness
suddenly decreases. On the other hand, in Example 2-23, the
brightness is scarcely decreased and nearly constant irrespective
of the distance from the take-out electrode and moreover, as shown
in FIG. 3B, light emission over the entire surface is realized.
Working Example 2-5
[0414] With respect to the following Samples 2-1 to 2-6, the
above-described flexing test was performed and the flexibility was
evaluated according to the same evaluation standards (increase rate
K of surface resistance) as above.
[0415] Sample 2-1 is an ITO film sample having a surface resistance
of 300 .OMEGA./sq, where the ITO film is formed by sputtering.
[0416] Sample 2-2 is a transparent conductive film sample produced
using a transparent conductive film formed of PEDOT, and Sample 2-3
is a transparent conductive film sample having only a fine line
structure part formed by exposing and developing a light-sensitive
material having a light-sensitive silver salt-containing layer on a
support.
[0417] Sample 2-4 is a transparent conductive film sample having a
fine line structure part and a transparent conductive film, which
is produced by performing a calender treatment and further a
dipping treatment in hot water in the production process thereof.
Sample 2-5 is a transparent conductive film sample having a
transparent conductive film over the entire top surface of a
support, which is produced by performing a calender treatment and
further a dipping treatment in hot water in the production process
thereof. Sample 2-6 is a transparent conductive film sample having
a transparent conductive film on the entire top surface of a
support, which is produced by performing a calender treatment but
not performing a dipping treatment in hot water in the production
process thereof.
[0418] The evaluation results are shown in Table 2-3 and FIG.
6.
TABLE-US-00012 TABLE 2-3 Surface Resistance Before and After
Flexing Test (.OMEGA./sq) Sample 2-1 Sample 2-2 Sample 2-3 Sample
2-4 Sample 2-5 Sample 2-6 Before test 216 3.88 .times. 10.sup.6
0.211 0.645 0.0635 0.137 After test 3.99 .times. 10.sup.6 3.15
.times. 10.sup.6 0.271 0.713 0.0729 0.165
[0419] In Sample 2-1 using an ITO film, the increase rate was
18,480.33 and a very high increase rate was exhibited. On the other
hand, in Samples 2-2 to 2-6, the increase rate was 2 or less.
Incidentally, in Sample 2-2, an increase in the resistance value
did not arise and conversely, the resistance was decreased though
not much.
[0420] In this way, a transparent conductive film sample using an
ITO film is found to be insufficient in the flexibility, as
apparent also from Sample 2-1.
[0421] The production method of a conductive film and the
transparent conductive film of the present invention are not
limited to the embodiments described above, and various
constructions may be of course employed without departing from the
purport of the present invention.
INDUSTRIAL APPLICABILITY
[0422] According to the invention, there can be provided a
light-transmitting electromagnetic wave-shielding film having high
conductivity, electromagnetic wave-shielding properties and high
translucency, and having a black mesh portion. Further, according
to the invention, there can be provided a method for producing a
light-transmitting electromagnetic wave-shielding film having high
electromagnetic wave-shielding properties and high transparency,
and having a black mesh portion, in which the formation of a fine
line pattern is possible in a short process, and which can be
produced at low cost in large amounts.
[0423] Furthermore, according to the invention, there can be
provided a printed board having high conductivity and few pinholes.
Moreover, according to the invention, there can be provided a
method for producing a printed board, with possible formation of a
fine line pattern and small environmental loading at low cost in
large amounts.
[0424] The entire disclosure of each and every foreign patent
application from which the benefit of foreign priority has been
claimed in the present application is incorporated herein by
reference, as if fully set forth.
* * * * *