JP2001006435A - Black conductive paste composition, and black conductive thick film and forming method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a black conductive paste for forming a black conductive thick film having high conductivity, low lightness and low yellowness, and provide the black conductive thick film and a forming method therefor. SOLUTION: This photosensitive black conductive paste for forming a black conductive thick film 40 contains minute silver powder of a specific surface area of about 1.0-2.0 (m2/g) as an conductive component, and a black pigment 46 comprising Co3O4 powder. Thereby, the black conductive paste has high photosensitivity, i.e., high resolution. In the black conductive thick film 40 formed from the photosensitive black conductive paste, silver 44 and the black pigment 46 comprising Co3O4 are joined with a glass 48. Accordingly, the black conductive thick film 40 has sufficiently high conductivity, and sufficiently low lightness and yellowness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a black conductive paste composition, a black conductive thick film, and a method for forming a black conductive thick film.

[0002]

2. Description of the Related Art For example, in a hermetically sealed space formed between a pair of parallel flat plates, a plurality of light-emitting sections are provided in a matrix along one direction and another direction orthogonal thereto, and a plurality of light-emitting sections are provided in the plurality of light-emitting sections. A plurality of pairs of discharge electrodes provided so that one pair is located for each light-emitting section in order to selectively generate a discharge, and by emitting light using the discharge, characters, symbols, figures, etc. 2. Description of the Related Art A discharge display device that displays a desired image is known. For example, the luminescence of neon orange or the like accompanying the generation of plasma generated by gas discharge is directly used, or the luminescence of the phosphor excited by ultraviolet light generated by the plasma provided in the luminescent compartment is used. Such a plasma display panel (hereinafter, referred to as a PDP) is one example. Such a PDP is relatively easy to be thin and has a large display surface, and has a wide viewing angle and a fast response speed comparable to that of a cathode-ray tube. , For example red (RED),
3 or 4 provided with phosphors of three colors of green (GREEN) and blue (BULE)
It is expected that a thin full-color display device such as a wall-mounted television can be realized by forming one pixel from two light-emitting sections to enable multicolor display.

[0003]

FIGS. 1 (a) and 1 (b) show an example of the above-mentioned PDP.
Publication No. 6 and the like, AC type surface discharge PD having a three-electrode structure
It is a figure showing composition of P8. In the drawing, a longitudinal partition wall 14 extends in one direction in an airtight space formed between a front plate 10 and a rear plate 12 positioned parallel to each other.
A plurality of discharge spaces 16 each including a plurality of light-emitting sections are provided in the longitudinal direction, and a plurality of write electrodes 18 passing between the partition walls 14 along the one direction on the back plate 12. Is provided on the front plate 10 while being covered with the overcoat 32, and along the other direction orthogonal to the one direction, a dielectric layer 20 made of a low softening point glass such as borosilicate glass and magnesium oxide (MgO 2). ) Are provided with a plurality of pairs of display discharge electrodes (sustain electrodes) 24a and 24b covered with a protective film 22 made of
A phosphor layer 26 that is separately applied to each discharge space 16 is provided on the inner surface of the second and the surface of the partition wall 14. In the drawing, the display discharge electrode 24 is formed of an ITO (Indium) formed by a thin film process or the like in order to generate a surface discharge in a wide range and to reduce the shading of the display light emitted through the front plate 10 as much as possible. A transparent electrode 28 made of, for example, Tin Oxide: Indium Tin Oxide or ATO (Antimon Tin Oxide: Antimony Tin Oxide), and on the transparent electrode 28 at the outer end position in the width direction for each pair to supplement its conductivity. And a bus electrode 30 made of a thin film conductor or a thick film conductor. In the figure, 3
Reference numeral 4 indicates that the writing electrode 18 is made of thick film silver and the back plate 12 is made of soda.
This is an undercoat for suppressing the reaction between the two when made of lime glass.

The bus electrode 30 is used as a supplement to the conductivity of the transparent electrode 28 or used alone to reduce the voltage drop in the longitudinal direction of the bus electrode 30 as much as possible. While it is required to have a low resistance in order to reduce the temperature, a low reflectance is also desired. In the PDP 8 configured as described above, the inner surface 3 of the front plate 10 on which the bus electrode 30 is provided.
This is because light transmitted through the front plate 10 is viewed on the surface 38 side opposite to the surface 6, so that reflection of external light on the surface 38 is suppressed to obtain a high display contrast. Therefore, when forming a thin film, for example, after forming a black Cr (chromium) layer on the front plate 10 (more precisely, on the transparent electrode 28), Al (aluminum), Cu (copper), or the like is formed thereon. Is provided.
In the case of forming a thick film, RuO ₂ (ruthenium oxide) or Fe-Pd (silver-palladium) paste, Ag-Cu (silver-copper) alloying paste, or Ag (silver) paste may be used. Cr-Mn (iron-chromium-manganese) pigments and Cu-Cr-Mn
A black conductive paste to which a pyrochlore type oxide represented by a (copper-chromium-manganese) pigment is added as a black pigment is applied on the front plate 10 by using a thick film screen printing method or the like. Although the bus electrode 30 can be formed by any of the thin film method and the thick film method, the thick film method is advantageous in terms of manufacturing cost. The above-mentioned black pigment is added to reduce the reflectance, that is, the brightness of the thick film conductor. Here, “brightness” is a measure of the magnitude of the reflectance of the object surface and means the brightness of the color. For example, ideal black and white are expressed as L and L values quantified as 0 and 100, respectively. Is done.

However, since the above black pigment has low conductivity, if it is added to such an extent that the brightness becomes sufficiently low, the resistance value of the thick film conductor is significantly increased. For this reason, the addition amount of the black pigment is limited to a small amount that can satisfy the high conductivity required for the bus electrode 30 (display discharge electrode 24), so that the brightness of the bus electrode 30 becomes relatively high. There is a problem that high contrast of the display of the PDP 8 cannot be obtained. This is particularly problematic in alloying pastes that inherently have high resistance. On the other hand, among the above thick film conductors, those produced from Ag paste have a relatively low resistance, so that a large amount of black pigment is added to maintain relatively high conductivity to make the brightness relatively low. Can be. However, even in this case, the obtained brightness is not sufficient, and, for example, as shown in FIG. 2, one or both of the display discharge electrode pairs 24a and 24b (one in the figure) are directly on the front plate 10. In the case where only the bus electrode 30 formed with a film is used, Ag diffuses into the front plate 10 and yellows.
There is a problem that the yellowness increases and the contrast may decrease. It is known that the yellowing can be suppressed as the amount of the black pigment added increases, but in a thick-film conductor where it is desired to lower the brightness and yellowness while maintaining high conductivity, the above-mentioned allowable addition is considered. In the amount range, yellowing cannot be sufficiently suppressed. Incidentally, among the above black pigments, RuO ₂
(For example, those having a specific surface area of about 35 (m ² / g)) are relatively excellent in each of the above properties, but are expensive and are difficult to handle because they are fine powders. Incidentally, in the structure shown in FIG. 1, the display discharge electrode 24 is constituted by the transparent electrode 28 and the bus electrode 30 formed thereon,
It is desired that at least one of the display discharge electrodes 24a and 24b is constituted only by the relatively narrow bus electrode 30 in order to suppress a decrease in the translucency caused by the transparent electrode 28 and obtain higher luminance. It has been confirmed that there is no particular problem in terms of discharge characteristics even if this is done.

Incidentally, as one of the methods for forming the bus electrode 30 on the front plate 10 using the above black conductive paste, there is a method using a photolithography method. In this method, for example, a photosensitive conductive paste is applied to the entire surface on the inner surface 36 of the front plate 10 and dried to form a paste film having a predetermined thickness, and the paste film is exposed to light through a mask having a predetermined pattern to form a paste film. After being selectively cured, the unexposed portions are washed away with a developing solution, and further baked to form a thick film conductor. Therefore, it is easier to form a large-area and high-definition pattern as compared with a direct printing method such as a thick film screen printing method in which a pattern shift due to a screen distortion may occur. However,
In this conductor forming method, it is necessary to selectively expose and cure the paste film as described above. Therefore, if a large amount of black pigment is mixed into the paste for the purpose of lowering the brightness of the thick film conductor, the light irradiated during exposure will not sufficiently reach the inside of the paste film and the resolution will decrease. In addition, there is a problem that the amount of the black pigment that is miscible is further reduced as compared with the case where the thick film screen printing method is used, so that only a thick film conductor with higher brightness can be obtained. That is, even in a thick film conductor formed by the photolithography method, the brightness and the brightness are maintained while maintaining the high resolution.
It has been desired to further reduce the yellowness and the resistance value. Here, the “resolution” indicates the degree of the minimum distance at which two different points can be identified. The above problem is not limited to the bus electrode of the PDP as long as it is a thick film conductor which is required to have high conductivity and low brightness and yellowness, other electrodes provided on the front panel of the PDP, PDP, etc. It can also occur in other display electrodes, in-vehicle rear glass heat rays, etc.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a black conductive paste for forming a black conductive thick film having high conductivity and low brightness and low yellowness. An object of the present invention is to provide a method for forming a conductive thick film and a black conductive thick film.

[0008]

A first aspect of the present invention for achieving the above object is to provide a black conductive paste according to the present invention, which comprises silver powder, glass powder, an organic binder, an organic solvent, , A black pigment, and a black conductive paste composition used for forming a conductive thick film exhibiting black, wherein (a) the black pigment is made of Co ₃ O ₄ powder.

[0009]

According to the first aspect of the present invention, since the black conductive paste contains Co ₃ O ₄ powder as a black pigment,
Since the black conductive thick film to be formed is formed by combining silver and a black pigment composed of Co ₃ O ₄ with glass, the black conductive thick film has sufficiently high conductivity and sufficiently low brightness and yellowness. A film is obtained. That is, when the black pigment is added to the conductive paste as described above, the brightness and yellowness of the conductive thick film formed from the paste are reduced, while the resistance value of the conductive thick film is increased. In this case, the effect is not clear, but according to the results of the present inventors evaluating these properties for various pigments,
When Co ₃ O ₄ powder is added as a black pigment, the decrease in brightness and yellowness is remarkably large as compared with other black pigments, and the increase in resistance is suppressed. Therefore, it is possible to obtain a black conductive paste capable of forming a black conductive thick film having high conductivity and low brightness and low yellowness.

[0010]

[Other aspect of the first invention] In the above-mentioned first invention, the silver powder preferably has a specific surface area of 0.2 to 15 (m ² / g).
It is. With this configuration, since the silver powder contained in the paste is sufficiently small in a range in which the paste can be easily formed, a continuous silver film is preferably formed when applied and fired. The conductivity of the resulting black conductive thick film is further enhanced. By the way, if the specific surface area is less than 0.2 (m ² / g), it is difficult to form a continuous film after sintering because it is coarse and becomes porous and the resistance value rises remarkably. Since the diameter becomes too large, the printability also decreases. On the other hand, when it exceeds 15 (m ² / g), the dispersibility is remarkably reduced, so that it becomes difficult to form a paste. More preferably, the range of the specific surface area is 0.4 to 10 (m ² / g).

In the first invention, preferably,
The silver powder accounts for 40% of the total paste composition.
It is contained in the range of ~ 90 (parts by weight = wt%). In this case, since the content of the silver powder is sufficiently increased in a range where the paste can be easily formed, the film thickness after drying and firing can be sufficiently increased, so that higher conductivity can be obtained. In addition, more preferably, the range of the content of the silver powder is 50 to
80 (wt%).

In the first invention, preferably,
The glass powder has a specific surface area of 0.5 to 10 (m ² / g), more preferably 1 to 8 (m ² / g). 0.5 (m ² / g) is less than reduced printability with resistance value increases as opposed to 10 (m ² / g) to exceed the dispersibility is poor becomes a paste reduction becomes difficult. Further, as the glass powder, for example, a low softening point glass having a softening point of not more than 600 (° C.) containing lead borosilicate glass as a main component, that is, PbO-SiO ₂ -B ₂ O ₃ system glass, PbO-SiO ₂ -B ₂ O ₃ -Al ₂ O
₃ based _{glass, PbO-SiO 2 -B 2 O} 3 -ZnO based glass or the like is preferably used. In the case of glass powder having a softening point exceeding 600 (° C.), the glass component cannot give a sufficient anchor effect when the paste film formed on a predetermined substrate or the like is fired. High adhesion strength cannot be obtained,
In addition, there is a problem that the resistance value increases.

In the first invention, preferably,
The content of the glass powder is 0.5 to the whole paste.
20 (wt%), more preferably in the range of 1 to 10 (wt%). If it is less than 0.5 (wt%), the bonding strength between the conductive thick film and the substrate becomes insufficient, and if it exceeds 20 (wt%), the resistance value increases significantly.

[0014]

A second object of the present invention to achieve the above object is to provide a black conductive paste composition according to a second aspect of the present invention, which comprises a silver powder, a glass powder, an organic binder, Organic solvent, a photosensitive composition, comprising a black pigment, a photosensitive black conductive paste composition used for patterning a conductive thick film that exhibits a black color by exposure and development treatment, (a The specific surface area of the silver powder is 0.4 to 2.5 (m ² / g), and (b) the black pigment is Co ₃
Consists of O ₄ powder.

[0015]

In this way, the photosensitive black conductive paste has a fine specific surface area of 0.4 to 2.5 (m ² / g) of silver powder contained as a conductive component and a black pigment.
Since it is Co ₃ O ₄ powder, it has high photosensitivity and high resolution, and the black conductive thick film formed from the photosensitive black conductive paste has a black pigment consisting of silver and Co ₃ O ₄ Is formed by bonding with glass, so that a black conductive thick film having sufficiently high conductivity and sufficiently low brightness and yellowness can be obtained. That is, as described above, when a black pigment is added to the photosensitive conductive paste, the lightness and yellowness of the conductive thick film formed from the paste are reduced, while the resistance value of the conductive thick film is increased and the photosensitive thick film is exposed. As a result, the resolution is reduced. In this case, the effect is not clear, but according to the results of the inventors' evaluation of these properties for various pigments, when Co ₃ O ₄ powder is added as a black pigment, it is compared with other black pigments. As a result, the decrease in brightness and yellowness is remarkably large, and in addition to the increase in resistance value, in the case of a photosensitive paste, the decrease in resolution is suppressed. Therefore, a photosensitive black conductive paste capable of forming a black conductive thick film having high conductivity and low brightness and low yellowness can be obtained. If the specific surface area of the silver powder is less than 0.4 (m ² / g), it becomes difficult to form a continuous film at the time of firing, while 2.5
If (m ² / g) is exceeded, it becomes difficult to form a paste, and the organic binder necessary for holding the silver powder in the paste film increases, so that the thickness of the conductive thick film after firing becomes thin. In any case, the resistance value increases. Also, 2.
If it exceeds 5 (m ² / g), exposure becomes difficult, and the resolution decreases. More preferably, the range of the specific surface area of the silver powder is 0.1.
8 to 2.0 (m ² / g).

[0016]

[Another aspect of the second invention] In the second invention,
Preferably, the silver powder has a spherical shape. In this way, when compared with similar particle diameters,
Since the spherical particles have a small specific surface area and a large particle size per surface area, the conductivity can be increased by reducing the amount of the organic binder necessary for forming the paste film.
In addition, the spherical particles are less likely to scatter the irradiated light inside the paste film than in the case of a plate-like or irregular shape having many irregularities, so that the resolution is improved. Therefore, a photosensitive black conductive paste capable of forming a conductive thick film having higher conductivity while maintaining higher resolution can be obtained.

In the second invention, preferably,
The silver powder accounts for 40% of the total paste composition.
It is included in the range of ~ 80 (wt%). In this case, since the content of the silver powder is sufficiently increased in a range where the paste can be easily formed and the exposure can be easily performed, the film thickness after drying and firing can be sufficiently increased. Is obtained. If it exceeds 80 (wt%), the irradiated light does not sufficiently reach the inside of the paste film, so that the resolution is remarkably reduced.

In the second invention, preferably,
The glass powder has a specific surface area of 0.5 to 10 (m^Two/ g). 0.
5 (m^Two/ g), the resistance increases and the particle size increases.
Printability (e.g., line edge after development)
Failure), and 10 (m^Two/ g)
It becomes worse and becomes difficult to paste. Also, glass powder
As, for example, softening mainly composed of lead borosilicate glass
Low softening point glass with a point of 600 (℃) or less, that is, PbO-Si
O_Two-B_TwoO_Three Glass, PbO-SiO_Two-B_TwoO_Three-Al_TwoO_ThreeGlass, Pb
O-SiO_Two-B_TwoO_Three-ZnO-based glass, PbO-SiO_Two-B_TwoO_Three-Al_TwoO_Three-ZnO
Glass, Bi_TwoO _Three-SiO_Two-B_TwoO_Three Glass, ZnO-SiO_Two-B_TwoO_Three 
Glass, R_TwoO-ZnO-SiO_Two-B_TwoO_Three Glass (R_TwoO is Arca
(Metal oxide) is preferably used. The softening point is
For glass powder exceeding 600 (° C), form on a predetermined substrate, etc.
The glass powder is sufficient when firing the formed paste film
Since the anchor effect cannot be given,
High fixing strength cannot be obtained, and the resistance value rises
The problem arises. In addition, the water resistance and adhesion of glass
To increase the temperature, the softening point of the glass powder should be 350 (° C) or more
It is desirable that

In the second invention, preferably,
The content of the glass powder is 0.5 to the whole paste.
It is in the range of 10 (wt%). If it is less than 0.5 (wt%), the bonding strength between the conductive thick film and the substrate or the like becomes insufficient.

In the second invention, preferably,
The organic binder has water solubility. In this case, since the organic binder contained in the conductive paste has water solubility in order to hold the paste film in a predetermined shape on a predetermined substrate or the like, the organic binder is used as a developing solution in a developing process for forming a pattern. Water can be used. Therefore, irrespective of the material of the substrate or the like on which the black conductive thick film is provided, direct damage such as erosion or deterioration as in the case of using an alkaline aqueous solution as a developing solution, foaming during firing due to a residue of the developing solution, etc. Indirect damage to the substrate or the like is suppressed.

In the second invention, preferably,
The organic binder is a cellulose derivative. In this case, since the cellulose derivative has good water solubility, there is an advantage that water can be used as a developing solution in a developing process for forming a pattern.

In the second invention, preferably,
The cellulose derivative comprises one or more of hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, carboxyethylcellulose, carboxyethylmethylcellulose, and salts thereof. Since each of these has particularly good water solubility among cellulose derivatives, the advantage that development processing with water is further facilitated as compared with the case of using other cellulose derivatives such as methylcellulose, ethylcellulose and ethylhydroxyethylcellulose. There is. In addition, since they have high compatibility with silver powder and black pigment and low reactivity with metal ions existing on the surface of glass powder, the change in viscosity and gelation of the black conductive paste are suppressed, resulting in stability. Because of its excellent properties, high preservability can be obtained.

In the second invention, preferably,
The content of the above organic binder is in the range of 5 to 20 (wt%) based on the whole paste. If the amount is less than 5 (wt%), the holding power of silver powder or glass powder in the paste film becomes insufficient, and the pattern portion tends to peel off during development. On the other hand, if it exceeds 20 (wt%), the content of the silver powder is relatively reduced, so that the thickness of the black conductive thick film after firing becomes thin and the resistance value is increased.

In the second invention, preferably,
The photosensitive composition is composed of a photopolymerizable compound and a photopolymerization initiator. In this way, when the photosensitive black conductive paste forms a pattern by exposing and developing the paste film formed therefrom, the exposed portion is cured, thereby forming the pattern of the black conductive thick film. So-called negative type.

The above-mentioned photopolymerizable compound is preferably contained in the range of 3 to 20 (wt%) based on the whole paste. If it is less than 3 (wt%), exposure failure, that is, the pattern portion is not sufficiently cured, and if it exceeds 20 (wt%), the conductivity of the formed black conductive thick film is remarkably reduced. Further, as the photopolymerizable compound, for example, acrylic acid, methacrylic acid, fumaric acid, maleic acid, monomethyl fumarate, monoethyl fumarate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate,
Ethylene glycol monomethyl ether acrylate,
Ethylene glycol monomethyl ether methacrylate, ethylene glycol monoethyl ether acrylate, ethylene glycol monoethyl ether methacrylate, glycerol acrylate, glycerol methacrylate, acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl Methacrylate, isobutyl acrylate, isobutyl methacrylate, 2-ethylhexyl acrylate,
2-ethylhexyl methacrylate, benzyl acrylate, monofunctional monomers such as benzyl methacrylate, ethylene glycol diacrylate, ethylene glycol monomethacrylate, triethylene glycol monoacrylate, tetraethylene glycol monoacrylate,
Nonaethylene glycol monoacrylate, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylate, triethylene glycol monomethacrylate, tetraethylene glycol monomethacrylate, nonaethylene glycol monomethacrylate,
Dipropylene glycol monoacrylate, tripropylene glycol monoacrylate, tetrapropylene glycol monoacrylate, dipropylene glycol monomethacrylate, tripropylene glycol monomethacrylate, butylene glycol monomethacrylate,
Propylene glycol monoacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, nonaethylene glycol diacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, nonaethylene glycol dimethacrylate , Dipropylene glycol diacrylate, tripropylene glycol diacrylate, tetrapropylene glycol diacrylate, dipropylene glycol dimethacrylate, tripropylene glycol dimethacrylate, butylene glycol dimethacrylate, propylene glycol diacrylate, trimethylolpropane triacrylate, trime Roll propane trimethacrylate, tetramethylolpropane tetraacrylate, tetramethylolpropane tetramethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, dipentaerythritol pentaacrylate, dipentaerythritol pentamethacrylate, dipentaerythritol Pentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate,
Examples thereof include polyfunctional monomers such as cardo epoxy diacrylate, and particularly, triethylene glycol monoacrylate, tetraethylene glycol monoacrylate, triethylene glycol monomethacrylate, tetraethylene glycol monomethacrylate, pentaerythritol triacrylate, and pentaerythritol trimethacrylate. Is preferably used. These are easily decomposed and volatilized at the time of firing, so that it is difficult to lower the electrical characteristics of the formed black conductive thick film, and can form a highly sensitive photosensitive black conductive paste.

Examples of the photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2,2-
Dimethoxy-1,2-diphenylethan-1-one, 2-methyl
-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2-hydroxy -2-
Methyl-1-phenylpropan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 1- [4- (2-
(Hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 3,3-dimethyl-4-methoxy Benzophenone, benzophenone, 1-chloro-4-propoxythioxanthone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-dodecylphenyl) -2-hydroxy-2- Methylpropan-1-one, 4-benzoyl-
4'-methyldimethyl sulfide, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, butyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 4 -
2-isoamyl dimethylaminobenzoate, 2,2-diethoxyacetophenone, benzyldimethylketal, benzyl-β-methoxyethylacetal, 1-phenyl-1,2-
Propanedione-2- (ο-ethoxycarbonyl) oxime, methyl o-benzoylbenzoate, bis (4-dimethylaminophenyl) ketone, 4,4'-bisdiethylaminobenzophenone, 4,4'-dichlorobenzophenone, benzyl, benzoin , Benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether,
Benzoin-n-butyl ether, benzoin isobutyl ether, benzoin butyl ether, p-dimethylaminoacetophenone, p-tert-butyltrichloroacetophenone, p-tert-butyldichloroacetophenone, thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, dibenzosuberone , Α, α-dichloro
-4-phenoxyacetophenone, pentyl-4-dimethylaminobenzoate and the like. The photopolymerization initiator is preferably in a proportion of 0.05 to
It is included in the range of 10 (wt%). If it is less than 0.05 (wt%), poor exposure, that is, polymerization of the photopolymerizable compound does not sufficiently proceed, and the effect of the pattern portion becomes insufficient. On the other hand, 10 (wt%)
When the ratio exceeds, the conductivity of the formed black conductive thick film is significantly reduced.

[0027]

[Other Embodiments of the First and Second Inventions] In the first and second inventions, preferably, the specific surface area of the black pigment is 1 to 20 (m ² / g). By doing so, the specific surface area of the black pigment is made sufficiently large in the range where the conductivity of the black conductive thick film is kept sufficiently high and in the case of the photosensitive paste, the resolution is also kept sufficiently high. From that
Good color development of black is obtained, and the brightness is sufficiently reduced. If it is less than 1 (m ² / g), the brightness is not sufficiently reduced, and if it exceeds 20 (m ² / g), the resistance increases and the resolution decreases in the case of a photosensitive paste. Is remarkable. The range of the specific surface area is more preferably 2 to 15 (m ² / g).

In the first and second inventions,
Preferably, the black pigment is contained in the range of 0.5 to 10 (wt%) in a ratio to the whole paste composition. In this case, the content of the black pigment is sufficiently large in a range where the conductivity of the black conductive thick film is kept sufficiently high and in the case of the photosensitive paste, the resolution is also kept sufficiently high. As a result, a black color is favorably obtained, and the brightness is sufficiently reduced. If the amount is less than 0.5 (wt%), the decrease in brightness is insufficient, while if it exceeds 20 (wt%), the resistance value increases and the resolution decreases remarkably. Also,
The range of the content is more preferably 1 to 8 (wt%).

[0029]

According to a third aspect of the present invention, there is provided a black conductive thick film which is provided on a predetermined substrate in a predetermined pattern, and is formed of silver and black. A black conductive thick film in which a pigment is bonded with glass, wherein (a) the black pigment is made of Co ₃ O ₄ .

[0030]

According to the third aspect of the present invention, since the black conductive thick film has the black pigment composed of Co ₃ O ₄ ,
As described in the effect of the invention, Co ₃ O ₄ has a large effect of lowering the brightness and yellowness of the black conductive thick film as compared with other black pigments, and furthermore, does not increase the resistance value so much, so that A black conductive thick film having sufficiently high properties and sufficiently low brightness and yellowness is obtained.

[0031]

According to another aspect of the third invention, in the above third invention, preferably, the black conductive thick film is provided on the opposite side of the one side of the translucent substrate observed from a predetermined one side. A black conductive layer provided on the other surface and containing the black pigment, and a high-brightness high-conductive layer provided with a higher brightness and higher conductivity than the black conductive layer and stacked thereabove. It is a thing. With this configuration, the black conductive thick film is formed by laminating the black conductive layer containing the black pigment and the high-brightness and high-conductive layer having higher brightness and higher conductivity. The conductivity of the entire film is sufficiently enhanced by the high brightness and high conductivity layer. On the other hand, on one surface side of the light-transmitting substrate on the viewing side, the black conductive layer of the two types of stacked conductive layers is observed through the light-transmitting substrate. The color tone of the film is substantially determined by the black conductive layer. At this time, since the conductivity of the black conductive thick film is secured by the high brightness and high conductive layer, the conductivity of the black conductive layer may be relatively low, so the amount of the black pigment contained in the black conductive layer may be sufficiently large. As a result, the brightness and yellowness of the black conductive layer and thus the black conductive thick film can be sufficiently reduced. Therefore, a black conductive thick film having high conductivity and low brightness and low yellowness can be obtained. In addition, since the black conductive layer also has a certain degree of conductivity, even when such a black conductive film constitutes the bus electrode 30 which is used to be overlapped with the transparent electrode 28 in the above-described PDP 8, even if the bus electrode 30 is formed between them, Can be sufficiently reduced when viewed from the above-mentioned one surface side while ensuring the conductivity.

In the third aspect of the invention, preferably, the black conductive thick film is formed by exposure and development using a conductive paste containing a photocurable compound. According to this configuration, when the black conductive thick film is patterned by the so-called photolithography method by exposure and development, the black pigment is composed of Co ₃ O ₄ , which is described in the effect of the second invention. As described above, a black conductive thick film having sufficiently high conductivity and sufficiently low brightness and yellowness can be obtained without significantly lowering the resolution during exposure and development.

In particular, when the black conductive thick film is composed of the above-mentioned black conductive layer and high-brightness high-conductive layer, and when they are patterned by using a conductive paste containing a photocurable compound, Since the high-brightness high-conductivity layer is higher in brightness than the black conductive layer, it is easy to expose, and compared to the case where the entire black conductive thick film is composed of the black conductive layer, Even if the black conductive paste to be formed is hardly exposed, sufficient exposure properties can be secured as a whole. Therefore, since the amount of the black pigment contained in the black conductive layer hardly affects the conductivity and the exposing property of the entire conductive thick film, the amount of the black pigment contained therein is sufficiently increased to extend the black conductive layer. The brightness and yellowness of the black conductive thick film can be sufficiently reduced. Therefore, a black conductive thick film having low brightness and low yellowness can be obtained while maintaining high conductivity and high resolution during film formation.

In the third aspect of the present invention, the black pigment preferably has a specific surface area of 1 to 20 (m ² / g).
In this case, the specific surface area of the black pigment contained in the black conductive thick film is such that the conductivity of the film is kept sufficiently high and a pattern is formed through exposure and development using a photosensitive paste. In the above, since the resolution is sufficiently increased in a range where the resolution is also kept sufficiently high, black color development is favorably obtained and the brightness is sufficiently reduced. If it is less than 1 (m ² / g), the decrease in brightness is insufficient, and if it exceeds 20 (m ² / g), on the other hand, the resistance value is increased and the resolution is significantly reduced. The range of the specific surface area is more preferably 2 to 15 (m ² / g).

In the third aspect of the present invention, preferably, the black pigment is contained in the range of 0.5 to 20 (wt%) in a ratio to the whole of the black conductive thick film. In this case, the content of the black pigment is high when the conductivity of the black conductive thick film is kept sufficiently high and the resolution is high when the pattern is formed through exposure and development using a photosensitive paste. Since the color is set sufficiently large in a range where the color is kept sufficiently high, black color development is favorably obtained and the brightness is sufficiently reduced. If the amount is less than 0.5 (wt%), the decrease in brightness is insufficient, while if it exceeds 20 (wt%), the resistance value increases and the resolution decreases remarkably. The content range is more preferably 1 to 8 (wt%).

[0036]

A fourth aspect of the present invention for achieving the above-mentioned object is to provide a method of forming a black conductive thick film according to the present invention. A method of forming a black conductive thick film in a predetermined pattern on the other surface of the transparent substrate opposite to the one surface thereof, wherein (a) the first invention or the second invention is formed on the other surface of the translucent substrate. A black paste film forming step of applying any of the black conductive paste compositions to form a black conductive paste film, and (b) having higher brightness and higher conductivity than those produced from the black conductive paste film A high-brightness high-conductivity paste composition for forming a film having a predetermined thickness is formed by applying a high-brightness high-conductivity paste composition for forming a film on the black conductive paste film and forming a high-brightness high-conductivity paste film. A paste film forming step, and (c) a conductive paste Firing the strike layer and a firing step of generating a black conductive thick film of a predetermined pattern is to include.

[0037]

In this way, when forming a black conductive thick film, in the black paste film forming step, any one of the first and second inventions is applied to the other surface of the light-transmitting substrate. A black conductive paste composition is applied to form a black conductive paste film, and in the high brightness paste film forming step, a film having higher brightness and higher conductivity than that generated from the black conductive paste film is formed. A high-brightness, high-conductivity paste composition is applied on the black conductive paste film to form a high-brightness, high-conductivity paste film, whereby a conductive paste film having a predetermined thickness is formed. The conductive paste film is fired to produce a black conductive thick film having a predetermined pattern. Therefore, the black conductive thick film is formed by stacking the black conductive layer generated from the black conductive paste film and the high brightness high conductive layer generated from the high brightness high conductive paste film, so that the entire conductive film is formed. The performance is sufficiently enhanced by the high brightness and high conductivity layer. On the other hand, on one surface side of the light-transmitting substrate on the viewing side, the black conductive layer of the two types of stacked conductive layers is observed through the light-transmitting substrate. The color tone of the film is substantially determined by the black conductive layer. At this time, since the conductivity of the black conductive thick film is secured by the high brightness and high conductive layer, the conductivity of the black conductive layer may be relatively low, so the amount of the black pigment contained in the black conductive layer may be sufficiently large. As a result, the brightness and yellowness of the black conductive layer and thus the black conductive thick film can be sufficiently reduced. Therefore, a black conductive thick film having high conductivity and low brightness and low yellowness can be formed.

[0038]

Another aspect of the fourth invention is that, in the above-mentioned fourth invention, a more preferable aspect of the method for forming a black conductive thick film is that the black conductive paste composition is formed by the second invention. A photosensitive black conductive paste composition, wherein the following two steps are performed prior to the firing step after the high-brightness paste film forming step, and (d) the conductive paste through a shielding film having a predetermined opening pattern. An exposure step of selectively exposing the film; and (e) a development step of cleaning and removing an uncured portion of the conductive paste film with a predetermined developer after the exposure step.

In this way, after the high-brightness paste film forming step, in the exposure step, the conductive paste film is selectively exposed through the shielding film having a predetermined opening pattern. In the process, the non-cured portion of the conductive paste film is washed and removed with a predetermined developing solution, and thereafter, the baking process is performed. Therefore, since the black conductive thick film is patterned by the so-called photolithography method using the photosensitive black conductive paste composition, a high-precision pattern can be formed more easily than when the pattern is formed by the thick film screen printing method. can get.
At this time, the conductive paste film formed on the black conductive thick film is formed by laminating a black paste film and a high-brightness high-conductivity paste film. Of these, the high-brightness high-conductivity paste film is a black paste containing a black pigment. Exposure is easier than film. Therefore, in addition to the conductivity of the black conductive thick film generated as described above being ensured by the high brightness and high conductive layer,
Compared to the case where the whole is generated from the black paste film,
Even if the black paste film is hardly exposed, sufficient exposure properties can be secured for the entire conductive paste film, so that the amount of the black pigment contained therein can be relatively large. According to the above, even when a black conductive thick film is formed through exposure and development processing using a photosensitive black conductive paste, the brightness and yellowness are further increased while maintaining high resolution and conductivity of the generated film. Can be lower.

In the fourth aspect of the present invention, the high-brightness and high-conductivity paste composition preferably contains silver powder in a range of 50 to 90 (wt%) based on the whole paste composition. In this case, since the silver powder content of the high-brightness and high-conductivity paste that exclusively contributes to securing the conductivity is sufficiently increased, the resulting black conductive thick film as a whole has sufficiently high conductivity. Is given. In addition,
When the content of the silver powder is less than 50 (wt%), the conductivity becomes insufficient, while when it exceeds 90 (wt%), it becomes difficult to form a paste. When a photosensitive paste composition having photosensitivity is used, when the content exceeds 80 (wt%), the irradiated light does not sufficiently reach the inside of the paste film, so that the resolution is significantly reduced. The problem also arises.

[0041]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 3A is a perspective view showing a state in which a black conductive thick film 40 according to one embodiment of the present invention is formed on a substrate 42, and FIG. It is a figure which shows typically the structure of the black conductive thick film 40 in the cross section seen from b. The black conductive thick film 40 is a thick film conductor formed by baking a photosensitive black conductive paste, which is a kind of a thick film conductive paste, as described later, and has a thickness of about 10 (μm) and a width of 50 (μm). ), And as shown in the figure, silver 44 serving as a conductive component and black pigment 46 serving as a coloring component are bonded by glass 48. The substrate 42 is, for example, a flat glass plate made of soda lime glass or the like and having high translucency. The glass 48 also has a function of fixing the black conductive thick film 40 to the substrate 42. I have. The black conductive thick film 40 constitutes, for example, the bus electrode 30 of the PDP 8 shown in FIG. 1 or FIG. 2, and the substrate 42 corresponds to, for example, the front plate 10 in FIG. In FIG. 3, the bus electrode 30 is shown.
Is shown provided directly on the substrate 42, but the black conductive thick film 40 is provided on the transparent electrode 28 as shown in FIG. 1 or FIG. You may.

The above-mentioned black pigment 46 is made of, for example, Co ₃ O ₄ having a specific surface area of about 3 to 13 (m ² / g) measured by a BET specific surface area measuring method and made of Co ₃ O ₄ which is black. Are dispersed almost uniformly. For this reason, the black conductive thick film 40 has a relatively low blackness of about 35 to 55 when observed through the transparent substrate 42 from the viewing direction indicated by the arrow in FIG. On the other hand, the resistance value is
100 (μm) with an interval of about 80 (mm) along the longitudinal direction
The value between two points of the pattern having a width of about m) is as low as about 10 to 15 (Ω) (for example, measured with a multimeter), and has high conductivity. Therefore, when used for the bus electrode 30 or the like of the PDP 8 as described above, good optical and electrical characteristics are exhibited. The “blackness” is a value obtained by measuring an L value representing lightness by a color difference meter (for example, manufactured by Minolta). In the following description, when simply referred to as "resistance value", the width of about 100 (μm) separated from each other by 80 (mm) along the longitudinal direction of the black conductive thick film 40 and the like, including other examples. It means the resistance between two points in the pattern.

Hereinafter, a method for forming the black conductive thick film 40 will be described with reference to FIG. 4 showing a main part of the process and FIG. 5 showing a cross-sectional shape at each stage of the forming process. When the black conductive film 40 functioning as the bus electrode 30 is provided on the front plate 10 shown in FIGS. This is omitted in the following description.

First, a photosensitive black conductive paste printing step S
In 1, the surface of the substrate 42 (when the transparent electrode 28 is provided, the substrate 42 and the transparent electrode 28 are used, for example, by a thick film screen printing method or a bar coater coating method. It is explained as ".)
A photosensitive black conductive paste is applied to the entire surface of the substrate. This photosensitive black conductive paste has, for example, a specific surface area of 1.0 to 2.0 (m ²
/ g) of spherical silver powder of about 60 (wt%) and specific surface area
1 ~2 (m ² / g) of about PbO-SiO ₂ -B ₂ O ₃ system 4 glass powder (glass frit) made of glass or the like (wt%) degree and, carboxymethyl cellulose and water such as hydroxypropylcellulose 5 (wt) of organic binder (polymer binder)
%) And the black pigment 46 (Co ₃ O ₄ ) is 2 to 6 (wt%).
About 5% by weight of a photopolymerizable compound such as pentaerythritol triacrylate, and about 5% by weight of a photopolymerizable compound such as 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one. A total of about 0.5 (wt%) of the initiator and the remainder of the organic solvent such as 3-methyl-3-methoxybutanol is 100 (wt.
%) And kneaded using, for example, a three-roll mill or the like to form a paste. The viscosity of the paste after kneading is, for example, 100 (Pa
s) degree.

Next, in the paste drying step S2, the substrate 4 is dried at a temperature of about 80 (° C.) for about 15 (minutes) using a far-infrared ray drier, for example.
The organic solvent is volatilized from the photosensitive black conductive paste applied on 2 to form a black conductive paste film 52. FIG. 5A shows this state. At this time, the thickness of the black conductive paste film 52 after drying is, for example, about 10 (μm).

In the subsequent exposure step S3, the black conductive paste film 52 is selectively exposed through a negative mask 54 having a predetermined size. FIG. 5B shows this state. In the figure, negative masks 54 are, for example, w
o = 50 (μm)
= 100 (μm), and is disposed above the black conductive paste film 52 at a slight distance. The length of the opening 56 is set according to the length of the black conductive thick film 40 formed on the substrate 42.
In addition, the above-described exposure process is performed using, for example,
The irradiation was performed by irradiating ultraviolet rays having a wavelength of about 350 (nm) with an energy dose of about 300 (mJ / cm ² ). As a result, a portion 58 indicated by oblique lines in the figure located immediately below the opening 56 is selectively exposed, and the photopolymerizable compound contained in the black conductive paste film is polymerized only in the exposed portion 58 by a polymerization reaction. It is cured and firmly fixed to the surface of the substrate 42.
On the other hand, the unexposed portions other than the exposed portions 58 are not changed at all.

In the developing step S4, for example, a developing process is performed by spraying water as a developing solution at a discharge pressure of about 2 (kgf / cm ² ) for about 20 (seconds). That is, a cleaning process is performed on the exposed substrate 42. As a result, the unexposed portion of the paste film 52 is selectively removed by being dissolved and washed away with water.
Only the exposed portion 58 is left on the second. Fig. 5 (c)
Indicates this state. Then, in the drying step S5, the substrate 42 (and the black conductive paste film 52) is dried, and in the conductor firing step S6, a firing process is performed using an electric furnace, for example, at about 550 (° C.) × 2 (hr). Is applied.
As a result, the organic components such as the polymer binder, the photopolymerizable compound, and the photopolymerization initiator are decomposed and removed by heating from the black conductive paste film 52, and at the same time, the glass 48 in which the glass powder is melted is melted. The silver 44 and the black pigment 46 are combined by the
0 is generated.

Here, Table 1 shows the characteristics of the black conductive thick film 40 formed as described above, in which the forming conditions were variously changed, along with the test conditions, along with the comparative examples. In the table below, 10 in the “resolution” column
Numerical values of 0 to 1000 are energy doses applied in the exposure step S3, and “「 ”indicates that the black conductive thick film 40 was formed according to the pattern of the negative mask 54, and“ △ ”indicates that
Indicates that the black conductive thick film 40 was able to be formed, but thinning of the lines and rattling of the pattern edge occurred, and “x” indicates that the paste film was not cured during the exposure, and the paste film 52 during the development.
Respectively indicate that the black conductive thick film 40 could not be formed. In the "organic binder type" column, "CMC" and "HPC" are carboxymethylcellulose and hydroxypropylcellulose, respectively.
In addition, other conditions not described in the table correspond to any of the examples.
In E and Comparative Example R, the method of measuring the blackness and the resistance value is as described above, all following the above process description.

[0050] [Table 1] (Example) units E1 E2 E3 E4 E5 silver powder specific surface area ^{(m 2 / g) 1.0 ←} ← 2.0 1.0 blending ratio (wt%) 60 ← ← ← ← glass specific surface area (m ² / g) 1 ← ← 2 1 Powder compounding ratio (wt%) 4 ← ← ← ← Organic type CMC HPC ← ← CMC binder compounding ratio (wt%) 5 ← ← ← ← Black type Co ₃ O ₄ ← ← ← ← Pigment Specific surface area (m ² / g) 7 ← 3 13 25 Mixing ratio (wt%) 2 6 4 2 ← Resolution 100 (mJ / cm ² ) × × × × × 300 ○ △ ○ ○ × 500 ○ ○ ○ ○ × 1000 △ ○ ○ △ △ Blackness (L value) 55 35 45 50 45 Resistance value (Ω) 10 15 12 15 15 (Comparative example) Unit R1 R2 R3 R4 R5 R6 R7 Silver powder Specific surface area (m ² / g) 1.0 ← ← ← ← ← ← Mixing ratio (wt%) 60 ← ← ← ← ← ← Glass specific surface area (m ² / g) 1 ← ← ← ← ← ← Powder Mixing ratio (wt%) 4 ← ← ← ← ← ← organic type CMC ← ← ← ← ← ← binding agent blending ratio (wt%) 5 ← ← ← ← ← ← melanoma _{- RuO 2 ← Fe-Cr-} Mn -based Cu-Cr-Mn pigment specific surface area ^{(m 2 / g) - 6} 30 5 ← ← 3 blending ratio (wt%) - 4 2 4 2 4 ← resolution 100 ( mJ / cm ² ) ○ × × × × × × 300 ○ × × × × × × 500 ○ × × × △ × × 1000 △ △ △ × △ △ △ Black chromaticity (L value) 70 55 50 55 60 55 60 Resistance value (Ω) 8 15 20 −10 15 10 units R8 R9 R10 R11 Silver powder Specific surface area (m ² / g) 0.3 3.0 1.0 ← Compounding ratio (wt%) 60 50 60 ← Glass specific surface area (m ² / g) ) 1 ← ← ← Powder compounding ratio (wt%) 3 ← 4 ← Organic type CMC ← ← ← Binder compounding ratio (wt%) 5 ← ← ← Black type Co ₃ O ₄ ← Co ₂ O ₃ ← Pigment specific surface area ( m ² / g) 7 7 4 ← Blending ratio (wt%) 2 ← ← 6 Resolution 100 (mJ / cm ² ) × × × × 300 ○ × △ × 500 ○ × ○ △ 1000 △ △ ○ △ Black Degree (L value) 55 55 65 55 Resistance value (Ω) 20 10 10 16

As is clear from the above Table 1 (Example)
In addition, Co as a black pigment 46_ThreeO_FourBy using
Set the irradiation dose of ultraviolet light in the optical step S3 appropriately.
If black according to the opening pattern of the negative mask 54,
The conductive paste film 52 is cured, and a predetermined pattern of black
A color conductive thick film 40 is obtained. In particular, the specific surface area is 3 to 13 (m
^Two/ g)_ThreeO_FourE using as a black pigment 46
According to 1 to E4, the energy dose of ultraviolet rays was set to 300 (mJ / c
m^Two) By the above, the blackness is 35-55 enough
A low and good black color is obtained, and the resistance value is 10 ~
 Black conductive thick film with sufficiently high conductivity of about 15 (Ω)
40 can be obtained.

However, in any of the above Examples E1 to E5, at an energy dose of about 100 (mJ / cm ² ), the reaction of the photopolymerizable compound becomes insufficient, so that the black conductive paste film 5
2 cannot be cured. Further, in Examples E1 and E4, since the over-exposure was performed with an energy dose of about 1000 (mJ / cm ² ) and the width of the hardened portion was wider than the opening portion 56 of the negative mask 54, the desired pattern was obtained. The black conductive thick film 40 cannot be obtained. In Example E2, 300
Even with an energy dose of about (mJ / cm ² ), the curing is not sufficient, and the pattern width becomes narrow and rattling occurs. Therefore, high resolution cannot be obtained in any case. In general,
Since the exposure tends to be more difficult as the amount of the black pigment 46 added is larger, the addition amount is as small as about 2 (wt%).
In E4 and E4, the energy dose resulting in overexposure is relatively low, and conversely, in Example E2, the lower limit of the energy dose required for proper exposure is presumed to have increased in the case where the addition amount is as large as about 6 (wt%). . In Example E5 in which the specific surface area of Co ₃ O ₄ was about 25 (m ² / g), excellent values were obtained for both the blackness and the resistance value. The volume needs to be very high. Further, the characteristic values shown in the table were evaluated for the black conductive thick film 40 having sufficient resolution.

On the other hand, in Comparative Example R1, black pigment 4
6, the blackness (L value) is as high as about 70, while high resolution is obtained and the resistance value is extremely low. In Comparative Examples R2 to R7, RuO was used as the black pigment 46.
₂ Fe-Cr-Mn system Other materials such as Cu-Cr-Mn system are used.However, in the case of any pigment, in the range of addition amount where blackness of about 50 to 60 is obtained, It was extremely difficult, and no black conductive thick film 40 having a predetermined pattern could be obtained. Comparative Examples R8 and R9 each used Co ₃ O ₄ as a black pigment. However, in Comparative Example R8, the specific surface area of the silver powder was as small as about 0.3 (m ² / g) and coarse. Although high resolution was obtained, the conductivity was insufficient. On the other hand, in Comparative Example R9, the specific surface area of the silver powder was
Since it is as large as about 3.0 (m ² / g), the resistance value is high and high resolution cannot be obtained. In other words, if the specific surface area of the silver powder is coarse, less than 0.4 (m ² / g), it becomes difficult to form a continuous film during firing, while if it exceeds 2.5 (m ² / g), it becomes difficult to paste and paste Since the amount of the organic binder necessary to hold the silver powder in the film increases, the thickness of the conductive thick film after firing decreases, and the resistance value increases in any case.

In Comparative Examples R11 and R12, Co ₂ O ₃ , a kind of cobalt oxide, was used as a black pigment. In Comparative Example R11 in which the amount of addition was small, the L value was too large. In Comparative Example R12 having a large amount, even at a relatively high energy dose, the black conductive paste film was insufficiently cured, and the pattern was thinned and rattled, resulting in insufficient resolution. That is, Co ₂ O ₃ cannot set an appropriate addition amount range.
Only ₃ O ₄ can achieve both resolution and blackness.

In Examples E1 to E5, silver powder having a specific surface area of about 1.0 or 2.0 (m ² / g) was added to 60 (wt%).
Glass powder with a specific surface area of 1 or 2 (m ² / g)
Although about 4 (wt%) is added, good results are obtained as shown in Table 1 for each specific surface area. Therefore, 0.4 to 2.5 (m ² /
The range of g) is preferable. Also, although no particular experimental results are shown, with respect to the glass powder, if the value is less than 0.5 (m ² / g), the printability is reduced because the resistance value increases and becomes coarse, and conversely, 10 (m ² / g) It has been confirmed that, when it exceeds, the dispersibility becomes poor and it becomes difficult to form a paste.

In short, in this embodiment, in the photosensitive black conductive paste for forming the black conductive thick film 40, the silver powder contained as a conductive component has a specific surface area of 1.
0 or 2.0 (m ² / g)
Since it is composed of Co ₃ O ₄ powder, it has high photosensitivity and thus high resolution, and the black conductive thick film 40 formed from the photosensitive black conductive paste contains silver and Co ₃ O _4. As shown in Table 1, a black conductive thick film having sufficiently high conductivity and sufficiently low brightness and yellowness can be obtained.

In the present embodiment, a spherical silver powder is used for the photosensitive black conductive paste. Therefore, when compared with the same particle diameter, the spherical particles have a small specific surface area and a large particle diameter per surface area, so that the amount of the organic binder necessary for forming the black conductive paste film 52 is reduced. In addition, the conductivity of the black conductive thick film 40 can be further increased. In addition, the spherical particles are less likely to scatter the irradiated light inside the paste film 52 as compared with the plate-like and irregular shapes, so that the resolution is also improved. Therefore, the black conductive thick film 4 having higher conductivity while maintaining higher resolution
Thus, a photosensitive black conductive paste capable of forming 0 is obtained.

In this embodiment, about 60 (wt%) of the silver powder constituting the photosensitive black conductive paste is contained in the paste composition as a whole. Therefore, since the content of the silver powder is sufficiently increased in a range where the paste can be easily formed and the exposure can be easily performed, the film thickness after drying and firing can be sufficiently increased, so that higher conductivity can be obtained.

In the present embodiment, the glass powder constituting the photosensitive black conductive paste has a specific surface area of 1
Alternatively, 2 (m ² / g) is used. Therefore, good printability of the paste can be obtained while securing sufficient dispersibility. Moreover, in this embodiment, since the glass powder made of PbO—SiO ₂ —B ₂ O ₃ having a softening point of about 550 (° C.) is used, the firing temperature in the conductor firing step S6 is relatively low. While sufficiently melting the glass powder. Therefore, the black conductive thick film 40 and the substrate 4
2 is secured.

In this embodiment, the content of the glass powder is about 4 (wt%) based on the whole paste. Therefore, the adhesion strength between the black conductive thick film 40 and the substrate 42 and the like can be further increased while suppressing an increase in the resistance value and a decrease in the resolution.

In this embodiment, water-soluble CMC or HPC is used as the organic binder constituting the photosensitive black conductive paste. Therefore, since the organic binder for maintaining the shape of the black conductive paste film 52 on the substrate 42 has water solubility, in the developing step S4 for forming a pattern, it is necessary to use water as a developer as described above. it can. Therefore, direct damage such as erosion or deterioration of the substrate 42 due to the developing solution, and indirect damage such as foaming at the time of baking due to a residue of the developing solution are caused on the substrate 4.
2 is suppressed. Moreover, particularly, HPC has high compatibility with silver powder and the black pigment 46 and low reactivity with metal ions present on the surface of the glass powder. Therefore, as shown in Example E4 in Table 1, silver powder is used. Even when the specific surface areas of the glass powder and the black pigment 46 are relatively large, the change in viscosity and gelation of the black conductive paste are suppressed, and the storage stability is enhanced.

Further, in this embodiment, the content of the organic binder (CMC or HPC) is about 5 (wt%) relative to the whole paste. Therefore, while sufficiently securing the holding power of the silver powder and the glass powder in the paste film and suppressing the pattern peeling in the developing step S4,
By increasing the thickness of the black conductive thick film 40 after firing, an increase in the resistance value can be suppressed.

In this embodiment, the photosensitive composition for imparting photosensitivity to the photosensitive black conductive paste is as follows:
It is composed of a photopolymerizable compound such as pentaerythritol triacrylate and a photopolymerization initiator such as 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one. Therefore, the photosensitive black conductive paste is used to expose the black conductive paste film 52 formed therefrom to the exposure step S.
In forming a pattern through Step 4 and the developing step S5, the exposed portion is cured to form a so-called negative type in which the pattern of the black conductive thick film 40 is formed.

The above photopolymerizable compound is contained in an amount of about 5 (wt%) relative to the whole paste, and the photopolymerization initiator is contained in an amount of about 0.5 (wt%). Therefore, since the respective addition amounts are reduced within a range where the pattern portion can be easily and sufficiently cured by exposure, a black conductive thick film 40 having high conductivity and excellent pattern accuracy can be obtained. In addition, in this embodiment, since pentaerythritol triacrylate, which is easily decomposed and volatilized during firing, is used as the photopolymerizable compound, the sensitivity of the photosensitive black conductive paste is increased, and The electrical characteristics of the conductive thick film 40 are further enhanced.

In this embodiment, the black pigment 46
Has a specific surface area of about 3 to 25 (m ² / g), particularly about 13 (m ² / g) or less in a range in which particularly preferable results are obtained, and the black conductive thick film 40 has sufficient conductivity. It is made sufficiently large as long as it is kept high and the resolution of the photosensitive black conductive paste is also kept sufficiently high. As a result, a good black color is obtained, and the brightness of the black conductive thick film 40 is sufficiently reduced.

In this embodiment, the black pigment 46
Is 2 to 6 (wt%) in proportion to the whole paste composition
The degree is set sufficiently large in such a range that the conductivity of the black conductive thick film 40 is kept sufficiently high and the resolution is also kept sufficiently high. Therefore, the color development of black is favorably obtained without greatly increasing the resistance value, and the brightness of the black conductive thick film 40 is sufficiently reduced.

Next, another embodiment of the present invention will be described. In the following embodiments, description of parts common to the above-described embodiments will be omitted.

Table 2 below shows the preparation conditions and the characteristic evaluation results when the black conductive thick film 40 is formed in the developing step S4 using an aqueous solution of 0.3 (%) sodium carbonate, which is an aqueous alkali solution, as a comparative example. It is also shown together. In Table 2 below, "Type of organic binder"
“EMA” and “EA” in the columns represent polymers of ethyl methacrylate and ethyl acrylate, respectively. Other formulation conditions except for the type of organic binder are the same as those in Table 1 for Examples E6 to E10 and Comparative Examples R12 to R18.
The manufacturing process is the same as the process shown in FIG. 4 except that the developing solution is different. As is clear from Table 2 below, when an organic binder soluble in an aqueous alkali solution is used, the same results as in Table 1 above in which a water-soluble organic binder is used are obtained.

[0069] [Table 2] (Example) Unit E6 E7 E8 E9 E10 silver powder specific surface area ^{(m 2 / g) 1.0 ←} ← ← 2.0 blending ratio (wt%) 60 ← ← ← ← glass specific surface area (m ² / g) 1 ← ← ← 2 Powder compounding ratio (wt%) 4 ← ← ← ← Organic type EMA ← ← ← EA binder compounding ratio (wt%) 5 ← ← ← ← Black type Co ₃ O ₄ ← ← ← ← Pigment Specific surface area (m ² / g) 7 ← 3 25 13 Mixing ratio (wt%) 2 6 4 2 ← Resolution 100 (mJ / cm ² ) × × × × × 300 ○ △ ○ × ○ 500 ○ ○ ○ × ○ 1000 △ ○ ○ △ △ Blackness (L value) 55 35 45 45 50 Resistance value (Ω) 10 15 12 15 15 (Comparative example) Unit R12 R13 R14 R15 R16 R17 R18 Silver powder Specific surface area (m ² / g) 1.0 ← ← ← ← ← ← Mixing ratio (wt%) 60 ← ← ← ← ← ← Glass specific surface area (m ² / g) 1 ← ← ← ← ← ← Powder Mixing ratio (wt%) 4 ← ← ← ← ← ← organic type EMA ← ← ← ← ← ← binding agent blending ratio (wt%) 5 ← ← ← ← ← ← black type - R uO ₂ ← Fe-Cr-Mn-based Cu-Cr-Mn-based pigment Specific surface area (m ² / g) − 6 30 5 ← ← 3 Mixing ratio (wt%) − 4 2 4 2 4 ← Resolution 100 (mJ ^{/ cm 2) ○ × × ×} × × × 300 ○ × × × × × × 500 ○ × × × △ × × 1000 △ △ △ × △ △ △ black chromaticity (L value) 70 55 50 55 60 55 60 resistance Resistance value (Ω) 8 15 20 − 10 15 10

FIG. 6 is a diagram schematically showing the structure of another black conductive thick film 60 which can constitute the bus electrode 30 and the like of the PDP 8 shown in FIG. 1 or FIG. In the figure, a black conductive thick film 60 is composed of a black black conductive layer 62 formed directly on a substrate 42 and a thin yellow yellow conductive layer 64 formed on the black conductive layer 62, It has dimensions of about 50 (μm) in width and about 5 to 6 (μm) in thickness, and has high conductivity with a resistance value of about 6 (Ω) or less, and a viewing direction indicated by an arrow in the figure. That is, the blackness when observed through the substrate 42 from the front surface 66 side has a low lightness of about 40. Therefore, as the bus electrode 30 or the like that requires conductivity and blackness, it is more preferably used than the black conductive thick film 40 shown in Table 1 or Table 2. In a discharge display device such as a PDP 8, the viewing direction is generally opposite to the back surface (inner surface) 68 located in the discharge space 16 where the electrode 30 and the like are provided, and is on the surface 66 side exposed to the external space. . In this embodiment, the substrate 42 corresponds to a translucent substrate, the front surface 66 corresponds to a predetermined surface, and the back surface 68 corresponds to the other surface on the opposite side.

The black conductive layer 62 is formed of the black conductive layer 62 described above.
As with the thick film 40, silver 44 and Co _ThreeO_FourBlack face consisting of
Including the material 46, for example, tB = 3 (μm)
Thickness of about 20 (Ω), blackness
Are configured to about 40. Because of this,
Since the blackness of the black conductive layer 62 to be placed is sufficiently low,
Blackness of the entire black conductive thick film 60 in its viewing direction
Is extremely low of about 40 determined by the black conductive layer 62.
Brightness. On the other hand, the yellow conductive layer 64 is formed of a conductive material.
Includes silver 44 but no black pigment 46
And has a thickness dimension of, for example, tY = 4 (μm).
The resistance is as low as 8 (Ω), but the blackness is about 70
And high brightness. Therefore, the black conductive thick film 60
Conductive layer 64 constituting a part thereof in the thickness direction of
Of the black conductive thick film 60
As the overall conductivity is increased and the resistance value is low as described above,
is there. As described above, the thickness of the black conductive layer 62 is comparative.
Thin, but blackness, that is, lightness is extremely low,
The color tone of the upper yellow conductive layer 64 passes through the black conductive layer 62.
Thus, it is not observed from the viewing direction side of the figure. Also,
The surface of the black conductive thick film 60 is directly covered without the substrate 42 interposed.
The color tone for close observation is the yellow conductive layer 6 located on the upper side.
According to the color tone of 4, light yellow and blackness is about 70
However, this yellow conductive layer 64 is directly visible from the viewing direction.
I can't. Therefore, the color tone (yellow or lightness) is P
It has no effect on the display quality of DP8 or the like. In this embodiment,
Therefore, the yellow conductive layer 64 corresponds to a high-brightness high-conductive layer.
I do.

The black conductive thick film 60 is provided on the substrate 42 according to, for example, the process shown in FIG. FIG. 7 shows a step S1 in the process chart shown in FIG.
Only the portions corresponding to S3 to S3 are shown, and S4 and subsequent steps follow the process diagram of FIG. Hereinafter, a method for forming the black conductive thick film 60 will be described with reference to FIG. 7 and FIG. 8 showing a cross-sectional structure of the substrate 42 at an intermediate stage of the process. First, in the photosensitive black conductive paste printing step S1, on the substrate 42 (and the transparent electrode 2), for example, using a thick film screen printing method or the like.
8) A photosensitive black conductive paste is applied to the entire surface, and in the paste drying step S2, for example, a drying treatment is performed for about 15 (minutes) at a temperature of about 80 (° C.) using a far-infrared dryer. Thus, the organic solvent is volatilized from the photosensitive black conductive paste applied on the substrate 42, and a black conductive paste film 70 similar to the black conductive paste film 52 shown in FIG. 5 is formed. At this time, the composition (kind and amount) of the photosensitive black conductive paste was the same as that of the examples shown in Table 1 except for the amounts of the materials shown in the upper part of Table 3 below.
Same as E1, the amount of silver powder is smaller than the case shown in Tables 1 and 2, and the amount of glass powder, the amount of black pigment,
And the amount of organic binder is increased. The dried film thickness of the black conductive paste film 70 is, for example, about 6 (μm). In this embodiment, the photosensitive black conductive paste printing step S1 and the paste drying step S2 correspond to a black paste film forming step.

[Table 3] Silver powder Glass powder Black pigment Organic binder black paste 40 10 5 7 Silver paste 60 3 0 7

Subsequent photosensitive conductive paste printing step S1-2
In the paste drying step S2-2, similarly to the case of the black conductive paste, a photosensitive silver paste not containing the black pigment 46 is printed on the entire surface of the black conductive paste film 70 to a temperature of about 80 (° C.). Dry at about 15 minutes. As a result, the silver paste film 72 is laminated on the black conductive paste film 70, and the dry film thickness becomes 14 as a whole.
A conductive paste film 74 of about 15 (μm) is formed. FIG. 8A shows this state. The silver paste film 7
Example 2 is the same as the black paste for forming the black conductive paste film 70 except that the amounts of the materials shown in the lower part of Table 3 above are excluded, that is, the examples shown in Table 1 above.
It is the same as the photosensitive black conductive paste of E1, and the film thickness after drying is about 8 (μm). Then, in the exposure step S3, similarly to the case shown in FIG. 4, the conductive paste film 74 is selectively applied from the silver paste film 72 side (that is, the substrate 42 is passed through) through the negative mask 54 having a predetermined size. (Directly). That is, the black conductive paste film 70 and the silver paste film 72 are integrally exposed.
FIG. 8B shows this state. In this embodiment, the photosensitive conductive paste printing step S1-2 and the paste drying step S2-2 correspond to a high-brightness paste film forming step.

At this time, the black conductive paste film 70 is irradiated with ultraviolet rays through the silver paste film 72, and the black pigment 46 which significantly impedes the transmission of irradiation light such as ultraviolet rays is contained in the silver paste film 72. Is not included, and
The film thickness and the film thickness of the black conductive paste film 70 itself are reduced as described above. Therefore, not only the silver paste film 72 directly irradiated with ultraviolet rays or the like, but also the black conductive paste film 70 located thereunder is suitably exposed. As a result, a portion 78 of the black conductive paste film 70 and the silver paste film 72 indicated by oblique lines in the figure is selectively cured in the same shape according to the opening pattern of the negative mask 54. That is, the black conductive paste film 70
A negative image is formed thereon. Therefore, a conductive paste film 74 having a predetermined pattern in which the black conductive paste film 70 and the silver paste film 72 are laminated is obtained by a subsequent development process (a development step S4 shown in FIG. 4), and is baked (the conductor paste shown in FIG. 4). By performing the firing step S6), FIG.
As shown in (2), a black conductive thick film 60 having a two-layer structure having both high conductivity and low brightness (blackness) is formed. In this example, since the same water-soluble organic binder as in Example E1 and the like was used, water was used as a developing solution in the developing step S4.

Here, Table 4 below shows the results of evaluating the resolution in the process of forming the black conductive thick film 60 of this embodiment (Example E11) when the black pigment made of a different material was used (Example E11). This is shown in comparison with Comparative Examples R19 and R20). All the comparative examples were evaluated under the same conditions as in Example E11 except that the type and the specific surface area of the black pigment were different. That is, the silver paste film 72 is provided on a black paste film formed by applying a photosensitive black conductive paste containing the following black pigment, and has a two-layer structure similar to that shown in FIG. A conductive paste film was formed, and its resolution and blackness and resistance of a black conductive thick film having a two-layer structure obtained by firing the conductive paste film were evaluated. As is clear from the table, according to the present example, a fine pattern can be formed by irradiating ultraviolet rays with an energy dose of about 300 to 500 (mJ / cm ² ), whereas in the comparative example, With the addition amount of the black pigment similar to that of the present embodiment, not only the brightness becomes high (that is, the brightness becomes poor), but also the cured paste film is peeled off from the substrate 42, or the paste film hardly hardens, In any case, a black conductive thick film having a predetermined pattern could not be obtained.

[Table 4] Unit Example E11 Comparative Example R19 Comparative Example R20 Black pigment Type Co ₃ O ₄ RuO ₂ Cu-Cr-Mn Specific surface area (m ² / g) 7 30 6 Resolution 100 (mJ / cm ² ) × × (peeling) × 300 ○ × (peeling) × 500 ○ × (peeling) × 1000 × × (peeling) △ Black chromaticity (L value) 40 45 55 Resistance value (Ω) 6 − −

In short, according to this embodiment, the black conductive thick film 60 is formed on the back surface 6 of the substrate 42 observed from the front surface 66 side.
8, a black conductive layer 62 containing a black pigment 46
, And a yellow conductive layer 64 having a higher brightness and higher conductivity than the yellow conductive layer 64. It is sufficiently enhanced by the layer 64. On the other hand, on the surface 66 side of the substrate 42 on the viewing side, since the black conductive layer 62 of the two conductive layers 62 and 64 laminated is observed through the substrate 42, the black conductive layer Membrane 60
Is substantially determined by the black conductive layer 62.
At this time, the conductivity of the black conductive thick film 60 is
Therefore, even if the conductivity of the black conductive layer 62 becomes relatively low, there is no problem in electrical characteristics. Moreover, since the yellow conductive layer 64 patterned by exposure and development similarly to the black conductive layer 62 has a higher brightness than the black conductive layer 62 and can be easily exposed, the entire black conductive thick film 60 is formed. Compared to the case where the black conductive layer 62 is formed, even if the black conductive paste for forming the black conductive layer 62 is hardly exposed, a sufficient exposure property can be secured as a whole. From these, the black conductive layer 6
Since the amount of the black pigment 46 contained in the black conductive layer 62 has almost no effect on the conductivity and the exposing property of the entire black conductive thick film 60, the amount of the black pigment 46 contained in the black conductive layer 62 is sufficiently increased.
As a result, the brightness and yellowness of the black conductive thick film 60 can be sufficiently reduced. Therefore, the black conductive thick film 60 having low brightness and low yellowness can be obtained while maintaining high conductivity and high resolution during film formation.

In this embodiment, when forming the black conductive thick film 60, the photosensitive black conductive paste is applied to the back surface 68 of the substrate 42 in the photosensitive black conductive paste printing step S 1 and the paste drying step S 2. Then, the black conductive paste film 70 is formed by drying, and the photosensitive conductive paste printing step S1-2 and the paste drying step S1-2.
In 2-2, a photosensitive silver paste for forming a yellow conductive layer 64 having higher brightness and higher conductivity than the black conductive layer 62 formed from the black conductive paste film 70 is applied to the black conductive paste film 70. A conductive paste film 74 having a predetermined thickness is formed by coating the conductive paste film 72 thereon and forming a silver paste film 72 thereon. A thick film 60 is created. Therefore, the black conductive thick film 60 is configured by stacking the black conductive layer 62 generated from the black conductive paste film 70 and the yellow conductive layer 64 generated from the silver paste film 72, as described above. Then, the black conductive thick film 60 having high conductivity and low brightness and low yellowness can be formed.

In this embodiment, the photosensitive conductive paste printing step S corresponding to the high-brightness paste film forming step is performed.
1-2, and after the paste drying step S2-2, in an exposure step S3, the conductive paste film 74 is selectively exposed through a mask 54 having a predetermined opening pattern, and after the exposure step S3, in a development step S4. Then, the uncured portion of the conductive paste film 74 is washed and removed, and then a conductor firing step S6 is performed. for that reason,
Since the black conductive thick film 60 is patterned by exposure and development using a photosensitive paste, a high-precision pattern can be obtained more easily than when the pattern is formed by the thick film screen printing method. At this time, the black conductive thick film 6
The conductive paste film 74 formed at 0 is formed by laminating a black conductive paste film 70 and a silver paste film 72, of which the silver paste film 72 is more exposed than the black conductive paste film 70 containing the black pigment 46. Is easy. Therefore, in addition to the fact that the conductivity of the black conductive thick film 60 generated as described above is ensured by the yellow conductive layer 64, as compared with the case where the entirety is generated from the black conductive paste film 70,
Even if the black conductive paste film 70 is hardly exposed to light, the conductive paste film 74 as a whole can secure sufficient exposure properties, so that the amount of the black pigment 46 contained therein can be relatively large. As described above, when forming the black conductive thick film 60 through exposure and development processing using the photosensitive black conductive paste, the brightness and the yellowness are further increased while maintaining the resolution and the conductivity of the generated film 60 high. Can be lower.

In this example, the photosensitive silver paste composition was used in an amount of 6% based on the total amount of the paste composition.
It contains silver powder in the range of 0 (wt%). In this case, since the content of the silver powder of the photosensitive silver paste that exclusively contributes to securing the conductivity is sufficiently increased, the black conductive thick film 60 to be generated has a sufficiently high conductivity as a whole. Is given.

Table 5 below shows the results of evaluation of the black conductive thick film of still another example, using black conductive paste in which the type and amount of the black pigment were variously changed.
A result obtained by forming a black conductive thick film similar to the black conductive thick film 40 shown in FIG. 3 by using, for example, a thick film screen printing method and the like and evaluating the results are shown together with the preparation conditions of the black pigment, along with a comparative example. Things. In the table, the “black pigment” column shows the type of the black pigment added to the paste, the “specific surface area” and “addition amount” columns show the specific surface area and the addition amount of the black pigment, “sheet resistance value”, “L value”. "And" b value "respectively represent the characteristics of the formed black conductive thick film. The `` sheet resistance value '' refers to the thickness of the black conductive thick film as 10 (μ
m). The “b value” indicates the degree of yellowness, and a larger value indicates a yellower color. The L value and the b value were measured by a color difference meter in the same manner as in the above-described examples.

[0083] [Table 5] amount added black pigment specific surface area sheet resistance value L value b value Example _{E12 Co 3 O 4 7 (m} 2 / g) 3.0 (wt%) 4.5 (mΩ / □) 50 9.5 E13 ↑ ↑ 6.0 7 41 6.0 E14 ↑ ↑ 8.0 10 37 5.1 E15 ↑ ↑ 10.0 18 33 4.5 E16 ↑ 2 3.0 4 58 16.2 E17 ↑ ↑ 6.0 6 50 13.4 E18 ↑ ↑ 8.0 9 44 11.7 E19 ↑ ↑ 10.0 15 41 10.5 Comparative Example R21 Co ₂ O ₃ 4 3.0 4 60 14.0 R22 ↑ ↑ 6.0 7 53 11.0 R23 ↑ ↑ 8.0 10 42 9.0 R24 ↑ ↑ 10.0 18 39 8.0 R25 RuO ₂ 35 2.0 6 50 10.0 R26 ↑ ↑ 3.0 7 45 8.0 R27 ↑ 10. 4.0 10.2 40 6.6 R28 ↑ ↑ 7.0 23.2 34 5.5 R29 Cu-Cr-Mn 6 3.0 7.5 50 26.3 R30 ↑ ↑ 6.0 10 43 20.0 R31 ↑ ↑ 8.0 14 40 18.0 R32 ↑ ↑ 10.0 18 38 16.0 R33 Fe-Cr-Mn 6 3.0 7 55 23.4 R34 ↑ ↑ 6.0 9 50 18.7 R35 ↑ ↑ 8.0 12 46 16.7 R36 ↑ ↑ 10.0 15 42 14.4

The paste constituents not shown in Table 5 above, that is, constituents other than the black pigment are the same in both the examples and the comparative examples. That is,
Both, the ratio as a conductive component surface area ² (m 2 / g) of about silver powder 60 (wt%) or so, softening point 400 (° C.) degrees with a specific surface area 2 (m ²
/ g) glass powder (for example, PbO-SiO ₂ -B ₂ O ₃ )
%), About 5 (wt.)
%) And butyl carbitol acetate (BCA) as an organic solvent containing a common component of about 30 (wt%). For the black pigment contained in the black conductive paste, the one shown in each “black pigment” column in the above table is described in each “addition amount” column with respect to a total of 100 (wt%) of the above common elements. The indicated amount was added.

The method of forming the black conductive thick film is the same in all the examples and comparative examples, and is, for example, as follows. That is, first, components of the paste (described later) are mixed and then kneaded by a three-roll mill to produce a black conductive paste. Next, a predetermined pattern is printed on the substrate 42 using a screen having the same opening pattern as the mask 54. Then, a black conductive thick film is formed by performing drying and baking. Therefore,
In this embodiment, a pattern is formed in advance during printing without performing the above-described exposure and development processing.
At this time, the printing surface is a top surface (non-tin surface) of the substrate 42 made of, for example, soda lime glass, that is, a surface located on an upper side when a glass plate is manufactured by a float method. The firing was performed using a belt furnace at a temperature of 550 (° C.) × 1.
The treatment was performed at 1.5 (hour) cycle with 0 (minute) hold.

FIGS. 9 and 10 are graphs showing the results shown in Table 5 above. FIG. 9 shows the relationship between the L value (brightness) and the sheet resistance value, and FIG. 10 shows the relationship between the L value and the b value (yellowness). Table 5 and FIG.
As is clear from FIG. 10, when any of the black pigments is used, the L value decreases as the amount of addition increases. These L value, b value, and sheet resistance value are
In the black conductive thick films used in the above-described methods, the characteristic values are desired to be as low as possible. Accordingly, it can be seen from both figures that when Co ₃ O ₄ is used as the black pigment 46 (Examples E12 to E19), a black conductive thick film having the above three characteristics is obtained. In particular, the specific surface area is 7 (m ² / g) Example E12 using fine Co ₃ O ₄
At E15, the b value and sheet resistance value for the same L value are both lower than when all other black pigments are used (that is, the curve connecting the measured values is located at the lower left). It is clear that the present invention is more suitable for the bus electrode 30 and the like. That is, Co ₃ O ₄ has a specific surface area of
It is preferable to use one larger than 2 (m ² / g). Although Comparative Examples R25 to R28 show relatively good characteristics, RuO ₂ has a specific surface area of about 35 (m ² / g), which is a fine powder and is difficult to handle, and is expensive. There's a problem.

In the PDP 8 and the like, the bus electrode 3
When the L value is 42 or less and the sheet resistance value is 10 (mΩ /
□) It is desired to be within the range indicated by oblique lines in the following FIG. 9 in order to increase display contrast and facilitate driving. Therefore, as is apparent from the results of Examples E12 to E15, when 7 (m ² / g) of Co ₃ O ₄ was used, the sheet resistance was 10 (mΩ /
□) From the following, it can be seen that the range of choice of the L value and the sheet resistance value is expanded.

While the embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be implemented in other embodiments.

For example, in the embodiments, the present invention
Although the case where the present invention is applied to the bus electrode 30 of P8 and the like has been described, the present invention is not limited to the case where a thick film conductor requiring low brightness (L value) and low resistance value (that is, high conductivity) is used. It is used in the same manner for electrodes for use in vehicles and for heating wires for vehicles.

Further, silver powder, glass powder, black pigment 46
The specific surface area, the content in the paste, and the like are not limited to the ranges shown in the examples, and properties such as L value, b value, and conductivity required for the black conductive thick films 40, 60, etc. It is appropriately changed in accordance with the fixing strength with respect to 42 and the like. However, in any case, it is desirable to set them within the above-mentioned preferable range.

The type and amount of the organic binder and organic solvent for preparing the paste, the photopolymerizable compound and the photopolymerization initiator contained in the photosensitive paste are determined according to the paste film 5.
2, 70 and the like, the conductivity required for the conductive thick film 40 and the like, and the resolution of the photosensitive paste are appropriately changed in consideration of the resolution and the like.

Examples of the organic binder include water-soluble CMC, HPC and ethyl cellulose as shown in Examples, EMA and EA polymers soluble in an aqueous alkali solution, cellulose derivatives and alkali-soluble polymers. One or more kinds of acrylic polymers and the like are appropriately used. However, when the black conductive thick film 40 or the like is formed using the photosensitive black conductive paste, the cellulose derivative is more preferable because the developing treatment can be performed with water. In the case of a non-photosensitive paste, the amount of the organic binder is preferably about 1 to 15 (wt%) based on the total weight of the paste.
More preferably, it is in the range of about 1.5 to 10 (wt%). 1 (wt
%), The solids settle or the printability deteriorates,
On the other hand, if it exceeds 15 (wt%), the printed film thickness becomes thin and the resistance value rises. In the case of the photosensitive paste, the range is preferably about 5 to 20 (wt%). 5 (wt%)
If it is less than 20%, the retention of silver powder or glass powder is weak, and peeling may occur during development. If it exceeds 20% by weight, the content of silver powder decreases, the film thickness becomes thin, and the conductivity increases. It is because it decreases. When an alkali-soluble acrylic polymer is used, an alkyd resin, a rosin resin, or the like may be further added.

Examples of the cellulose derivative include, for example, cellulose, ethyl cellulose, methyl cellulose, ethyl hydroxyethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, and the like.
Carboxyethyl methylcellulose and salts thereof can be used. However, since the photosensitive paste is preferably water-soluble which can be developed with water, a water-soluble cellulose derivative other than ethyl cellulose and ethyl hydroxyethyl cellulose among the above is preferably used.

Examples of the alkali-soluble acrylic polymer include [monomers having a carboxyl group such as acrylic acid, methacrylic acid, crotonic acid, cyanocinnamic acid, cinnamic acid, maleic acid, fumaric acid, and itaconic acid] and [acrylic acid]. Methyl, ethyl acrylate, methyl methacrylate, ethyl methacrylate, 2-hydroxymethyl acrylate, 2-
Hydroxyethyl acrylate, monomethyl fumarate,
Monoethyl fumarate, ethylene glycol monomethyl ether acrylate, ethylene glycol monomethyl ether methacrylate, ethylene glycol monoethyl ether acrylate, ethylene glycol monoethyl ether methacrylate, glycerol (mono) acrylate, glycerol (mono) methacrylate, acrylic amide, methacrylamide, Acrylonitrile,
Methacrylonitrile, isobutyl acrylate, isobutyl methacrylate, 2-ethylhexyl acrylate,
And a monomer such as 2-ethylhexyl methacrylate, benzyl acrylate, or benzyl methacrylate]. When this alkali-soluble acrylic polymer is used, the acid value is preferably about 50 to 250.
Conversely, if it exceeds 250, the coating properties and dispersibility deteriorate. The weight average molecular weight of the organic binder is preferably about 1,000 to 200,000, and more preferably about 5,000 to 150,000. In addition, if less than 1000, the adhesion to the substrate 42 becomes insufficient and the retention of the silver powder and the black pigment 46 decreases,
On the other hand, if it exceeds 200,000, the development time may be long, or development may not be possible.

Examples of the photopolymerizable compound include acrylic acid, methacrylic acid, fumaric acid, maleic acid, monomethyl fumarate, monoethyl fumarate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, ethylene glycol monomethyl ether acrylate, Ethylene glycol monomethyl ether methacrylate, ethylene glycol monoethyl ether acrylate, ethylene glycol monoethyl ether methacrylate,
Glycerol acrylate, glycerol methacrylate, acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, methyl acrylate,
Monofunctional monomers such as methyl methacrylate, ethyl acrylate, ethyl methacrylate, isobutyl acrylate, isobutyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, benzyl acrylate, benzyl methacrylate, ethylene glycol diacrylate, ethylene glycol monomethacrylate, and triethylene glycol mono Acrylate, tetraethylene glycol monoacrylate, nonaethylene glycol monoacrylate, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylate, triethylene glycol monomethacrylate, tetraethylene glycol monomethacrylate, nonaethylene glycol monomethacrylate, dipropylene glycol Noacrylate, tripropylene glycol monoacrylate, tetrapropylene glycol monoacrylate, dipropylene glycol monomethacrylate, tripropylene glycol monomethacrylate, butylene glycol monomethacrylate, propylene glycol monoacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol Diacrylate, tetraethylene glycol diacrylate, nonaethylene glycol diacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, nonaethylene glycol dimethacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, tetrapropylene Recall diacrylate, dipropylene glycol dimethacrylate, tripropylene glycol dimethacrylate, butylene glycol dimethacrylate, propylene glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate,
Tetramethylolpropane tetraacrylate, tetramethylolpropane tetramethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate,
Multifunctional such as dipentaerythritol pentaacrylate, dipentaerythritol pentamethacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, cardo epoxy diacrylate Monomers may be used.

The photopolymerization initiator includes 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2
-Diphenylethan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-
Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine Oxide, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propane-
1-one, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 3,3-dimethyl-4-methoxybenzophenone, benzophenone, 1-
Chloro-4-propoxythioxanthone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one , 4-benzoyl-4'-methyldimethyl sulfide, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate,
Butyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 4-dimethylaminobenzoic acid
-2-isoamyl, 2,2-diethoxyacetophenone, benzyldimethylketal, benzyl-β-methoxyethylacetal, 1-phenyl-1,2-propanedione-2- (ο-
Ethoxycarbonyl) oxime, methyl o-benzoylbenzoate, bis (4-dimethylaminophenyl) ketone,
4,4'-bisdiethylaminobenzophenone, 4,4'-dichlorobenzophenone, benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, benzoin butyl ether, p-dimethylamino Acetophenone, p-tert
-Butyltrichloroacetophenone, p-tert-butyldichloroacetophenone, thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, dibenzosuberone, α, α-dichloro-4-phenoxyacetophenone, pentyl-4-dimethylaminobenzoate, etc. are used. You may be.

Examples of the organic solvent include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, and propylene glycol. Monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monophenyl ether, diethyl Glycol dimethyl ether, diethylene glycol diethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether Acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monophenyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate Pro-plane glycol monopropyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-
Methoxy butyl acetate, 2-methyl-3-methoxy butyl acetate, 3-methyl-3-methoxy butyl acetate, 3-ethyl-3-methoxy butyl acetate, 2-ethoxy butyl acetate, 4-ethoxy butyl acetate, 4-
Propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 3-
Methyl-4-methoxypentyl acetate, 4-methyl-4-
Methoxypentyl acetate, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, ethyl isobutyl ketone, tetrahydrofuran, cyclohexane, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, 2-hydroxypropion Ethyl acid, 2-hydroxy-2-methyl, methyl-3-methoxypropionate, ethyl-3-methoxypropionate, ethyl-3-ethoxypropionate, ethyl-3-propoxypropionate, propyl-3 -Methoxypropionate, isopropyl-3-methoxypropionate,
Ethyl ethoxyacetate, ethyl oxyacetate, 2-hydroxy
-3- methyl methylbutanoate, methyl acetate, ethyl acetate,
Propyl acetate, isopropyl acetate, butyl acetate, methyl isoamyl carbonate, ethyl carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate,
Ethyl acetoacetate, benzyl methyl ether, benzyl ethyl ether, dihexyl ether, benzyl acetate,
Benzyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, benzene, toluene, xylene, cyclohexane, methanol, ethanol, propanol, butanol, 3-methyl-3-methoxybutanol, hexanol, cyclohexanol, ethylene glycol, diethylene glycol, Glycerin, terpineol, dihydroterpineol and the like may be used. Among the above, 3-methyl-3-methoxybutanol can reduce the reactivity between a metal ion existing on the surface of an inorganic material such as silver powder and glass powder and an organic binder soluble in an aqueous alkaline solution. Therefore, a change in viscosity and gelation of the paste are suppressed, and high storage stability is obtained. The content of the organic solvent in the paste is preferably about 1 to 40 (wt%) in the photosensitive paste. 1 (wt%)
If it is less than 40%, it is difficult to perform uniform application and contact exposure in the exposure step S6. In the case of a non-photosensitive paste, the range is preferably about 5 to 50 (wt%). If it is less than 5 (wt%), it is difficult to make a paste, and if it exceeds 50 (wt%), on the other hand, the film thickness becomes thin and the resistance value increases.

Further, the conductive paste may further contain other additives such as a dye, a plasticizer, a surfactant, an antifoaming agent, and a thermal polymerization inhibitor. As the dye, for example, cyanine green or the like can be used. As the plasticizer, in the photosensitive paste, dioctyl phthalate, didodecyl phthalate, triethylene glycol dicaprylate, dimethyl glycol phthalate, tricresyl phosphate, dioctyl adipate, dibutyl sebacate, triacetyl glycerin, and the like are preferably used. For the non-photosensitive paste used, dimethyl phthalate, dibutyl phthalate, dioctyl phthalate, polypropylene glycol and the like are preferably used. In addition, these plasticizers can also be used as an organic solvent.
As the defoaming agent, various types such as a silicone type and a fluorine type can be used.

In the embodiment, a photosensitive black conductive paste is applied to the substrate 42 by a thick film screen printing method or a bar coater and exposed and developed, or a pattern is directly formed by a thick film screen printing method. However, the method for forming the black conductive thick film 40 and the like is not limited to these. For example, the present invention is similarly applied to a case where the black conductive thick film 40 and the like are formed by a sand blast method, a lift-off method, or the like.

In the examples, the black conductive paste was prepared to have a viscosity of about 100 (Pa · s). . However, in the case of a photosensitive paste, in order to print the entire surface with a uniform thickness, it is preferable that the range is about 5 to 200 (Pas), and about 10 to 150 (Pas). The range is more preferred. In the case of direct printing, a viscosity range of about 50 to 500 (Pas) is preferable in order to suppress a decrease in pattern accuracy due to dripping of the paste, and 80 to 400 (Pas).
The range of (Pa · s) is more preferable.

In the embodiment, the black conductive paste film 52 is formed so as to have a thickness of about 10 (μm) after drying and the conductive paste film 74 has a thickness of about 5 to 6 (μm). The dry film thickness is appropriately changed in the range of, for example, about 5 to 20 (μm) according to the required film thickness of the black conductive thick films 40 and 60. When the required film thickness cannot be obtained by one application, such as when a dry thickness exceeding 20 (μm) is required, the paste may be repeatedly applied until the required film thickness is reached.

In the embodiment, in the paste drying step S2, drying is performed at a temperature of about 80 (° C.) for about 15 (minutes), and in the conductor firing step S6, firing is performed at a temperature of about 550 (° C.). However, the drying temperature and time are appropriately changed according to the thickness of the paste film, the type of the organic solvent, and the like, and further, in the photosensitive paste, the thermal polymerization initiation temperature of the monomer and the like, and the firing temperature is determined according to the type of the glass powder and the like. It is changed as appropriate. The preferable ranges are, for example, about 70 to 200 (° C.) and about 5 to 60 (minutes), respectively, for the drying temperature and time, and the firing temperature is the heat deformation temperature of the substrate 42 or 400 to 45 (minutes).
The black conductive film 40 in the sealing step treated at about 0 (° C.)
Taking into account thermal deformation such as 60, it is about 500-600 (° C).

Further, in the example, in the exposure step S3, the exposure was performed using ultraviolet rays having a wavelength of about 350 (nm), but the wavelength of the irradiation light is appropriately changed according to the type of the photopolymerizable compound. . In the examples, an ultra-high pressure mercury lamp was used as a source of ultraviolet rays.
High pressure mercury lamps, chemical lamps, etc. can be used,
The energy dose to be applied is appropriately changed, for example, in the range of about 20 to 1000 (mJ / cm ² ) in accordance with the exposure property of the black conductive paste film 52 and the like.

In the examples, the photopolymerizable compound is contained in the photosensitive black conductive paste,
In the exposure step S3, the exposed portion 58 was cured to form a pattern. Conversely, by using a compound or the like that can be decomposed by being exposed, a black conductive layer is formed in the unexposed portion. It may be configured such that a pattern such as the film 40 is formed. That is, the photosensitive composition is not limited to a photopolymerizable compound, and is polymerized, decomposed, added,
Various compositions can be used as long as they cause chemical reactions such as dimerization, oxidation, and reduction, and change in solubility and hardness. When a compound that decomposes by exposure is used, it is necessary to use a positive mask in which the opening 56 and the non-opening are reversed in place of the negative mask 54 in the exposure step S3.

In addition, although not specifically exemplified, the present invention
Various changes can be made without departing from the spirit of the invention.

[Brief description of the drawings]

FIG. 1 (a) is a perspective view, partially cut away, showing an example of a configuration of a PDP in which a black conductive thick film of the present invention can be provided, and FIG. It is a figure showing a section along the longitudinal direction of an electrode.

FIG. 2 is a diagram showing a cross-sectional structure when a display discharge electrode is directly formed on a front plate in the PDP of FIG. 1;

FIG. 3A is a perspective view showing a black conductive thick film according to an embodiment of the present invention, and FIG. 3B is a view schematically showing an enlarged cross section taken along line bb in FIG. is there.

FIG. 4 is a process chart illustrating a method for forming the black conductive thick film of FIG. 3;

5 (a) to 5 (c) are views showing the cross-sectional structure of the substrate at each stage of the film forming process of FIG.

FIG. 6 is a perspective view showing a black conductive thick film according to another embodiment of the present invention.

FIG. 7 is a process diagram illustrating a main part of a process of forming a thick black conductive film in FIG. 6;

8 (a) and 8 (b) are views showing the cross-sectional structure of the substrate at each stage of the film forming process of FIG. 7;

FIG. 9 is a graph showing a relationship between an L value and a sheet resistance value of a black conductive thick film according to another embodiment of the present invention.

10 is a graph showing the relationship between the L value and the b value of the black conductive thick film of FIG.

[Explanation of symbols]

 40: Black conductive thick film 42: Substrate 44: Silver 46: Black pigment 48: Glass

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshifumi Hayashi No. 1-336, Noritake Shinmachi, Nishi-ku, Nagoya City, Aichi Prefecture Noritake Co., Ltd. (72) Inventor Hiromitsu Sato 150 Nakamaruko Nakahara-ku, Kawasaki City, Kanagawa Prefecture East Within Kyo Chemical Industry Co., Ltd. EC24 EC30 EC53 EC54 4J038 BA021 EA011 HA066 HA216 HA486 KA06 KA08 KA20 NA20 5G301 DA03 DA33 DA34 DA42 DD01

Claims (17)

[Claims] 1. A black conductive paste composition comprising silver powder, glass powder, an organic binder, an organic solvent, and a black pigment, which is used to form a conductive thick film exhibiting black, A black conductive paste composition, wherein the black pigment comprises Co ₃ O ₄ (tricobalt tetroxide) powder. 2. A conductive film which has a photosensitivity containing silver powder, glass powder, an organic binder, an organic solvent, a photosensitive composition and a black pigment, and exhibits a black color by exposure and development treatment. A black conductive paste composition used for patterning a film, wherein the specific surface area of the silver powder is 0.4 to 2.5 (m ² / g), and the black pigment is made of Co ₃ O ₄ powder. Characteristic black conductive paste composition. 3. The black conductive paste composition according to claim 2, wherein the silver powder has a spherical shape. 4. The black conductive paste composition according to claim 2, wherein the silver powder is contained in a range of 40 to 80 (wt%) based on the whole of the paste composition. 5. The black conductive paste according to claim 2, wherein the organic binder has water solubility. 6. The black conductive paste according to claim 5, wherein the organic binder is a cellulose derivative. 7. The cellulose derivative may be hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, carboxyethylcellulose, carboxyethylmethylcellulose,
7. The black conductive paste according to claim 6, comprising one or more of these salts. 8. The specific surface area of the black pigment is 1 to 20 (m
² / g), the black conductive paste composition according to any one of claims 1 to 7. 9. The black conductive paste composition according to claim 1, wherein the black pigment is contained in a range of 0.5 to 20 (wt%) based on the whole of the paste composition. 10. A black conductive thick film provided on a predetermined substrate in a predetermined pattern, wherein silver and a black pigment are bonded by glass, wherein the black pigment is made of Co ₃ O _4. Black conductive thick film. 11. The black conductive thick film, the black conductive layer including the black pigment provided on the other surface of the light-transmitting substrate which is observed from a predetermined one surface side and opposite to the one surface, and The black conductive thick film according to claim 10, further comprising a high-brightness high-conductive layer provided on the upper side of the black conductive layer having higher brightness and higher conductivity than the black conductive layer. 12. The black conductive thick film according to claim 10, wherein the black conductive thick film is formed by exposure and development using a conductive paste containing a photocurable compound. 13. The black pigment has a specific surface area of 1 to 20.
13. The black conductive thick film according to claim 10, wherein the thickness is (m ² / g). 14. The black conductive thick film according to claim 10, wherein the black pigment is contained in the range of 0.5 to 20 (wt%) with respect to the entire black conductive thick film. . 15. A method of forming a black conductive thick film in a predetermined pattern on the other surface of the light-transmitting substrate, which is observed from the predetermined one surface side, on the other surface opposite to the one surface, the method comprising: A black paste film forming step of forming a black conductive paste film by applying the black conductive paste composition according to any one of claims 1 to 9 to the other surface, wherein the brightness is higher than that generated from the black conductive paste film. By applying a high-brightness high-conductivity paste composition for producing a high and high-conductivity film on the black conductive paste film to form a high-brightness high-conductivity paste film,
A step of forming a high-brightness paste film forming a conductive paste film having a predetermined thickness; and a step of firing the conductive paste film to generate a black conductive thick film having a predetermined pattern. Method of forming a film. 16. The black conductive paste composition according to claim 2, wherein the black conductive paste composition has the photosensitivity, and the black conductive paste composition has a high brightness paste film forming step and a high brightness paste film forming step. The following two steps to be performed, an exposure step of selectively exposing the conductive paste film through a shielding film having a predetermined opening pattern, and a non-cured portion of the conductive paste film after the exposure step is subjected to a predetermined process. The method for forming a thick black conductive film according to claim 15, further comprising a developing step of washing away with a developing solution. 17. The high-brightness, high-conductivity paste composition,
50 to 90 (wt%) based on the total paste composition
17. A silver powder containing silver powder in the range described above.
The method for forming a black conductive thick film according to (1).