JP2009135090A - Black conductive paste composition and method of manufacturing bus electrodes using the composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a bus electrode consisting of a single black layer having both masking effect and high electric conductivity, so as to improve use efficiency of a paste material, and to improve complexity of a conventional manufacturing process using a photolithography method so as to simplify the manufacturing process. <P>SOLUTION: A black conductive paste composition for forming a bus electrode 16 on a front glass substrate 11 constituting a PDP 10 in an offset printing method or screen printing method is characterized in that the composition includes: black oxide powder of 1-10% by mass; sulfide powder of 1-10% by mass; glass powder of 1-25% by mass; metal powder of 35-85% by mass; and the remainder organic vehicles, an average particle diameter of the black oxide powder is 0.05-0.5 μm, and a specific surface area of the black oxide powder is 3-50 m<SP>2</SP>/g. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a conductive black paste composition suitable for forming a bus electrode on a windshield substrate of a plasma display panel (hereinafter referred to as PDP), and production of the bus electrode using the composition. It is about the method.

  PDP applies voltage to the electrode pair of the discharge cell, which is a sealed space filled with gas, generates plasma discharge, and irradiates the phosphor applied in the discharge cell with ultraviolet rays generated from the gas, thereby exciting the phosphor. It is a display device that displays information by causing it to emit light.

The PDP image display method will be further described below with reference to FIG. In the PDP, a partition wall 13 is provided between the front glass substrate 11 and the rear glass substrate 12 to suppress the spread of the discharge to a certain region and to perform display in a prescribed cell, and to ensure a uniform discharge space. . A bus electrode 16 is provided on the inner surface of the front glass substrate 11, and an address electrode 17 is provided on the inner surface of the rear glass substrate 12 so as to face the bus electrode 16. Both substrates 11,
12 is defined by a partition wall 13. Gas is sealed in the partitioned interior, and a discharge space 14 is formed. The PDP generates plasma discharge between the bus electrode 16 and the address electrode 17 that are opposed to each other in the discharge space 14, so that ultraviolet rays generated from the gas sealed in the discharge space 14 are generated in the discharge space 14. The display is performed by being applied to the phosphors 18G, 18B, and 18R provided in.

  In recent years, there has been a demand for higher image quality of PDP, and one of the countermeasures is high contrast. Conventionally, the contrast of a PDP has been lower than that of a cathode ray tube television, but one of the causes for lowering the contrast is the high reflection luminance of room light.

  The room light is visible light, but the reflectance of the visible light to the phosphor in the discharge cell that constitutes the PDP is high, so that the room light reflected by the phosphor enters the viewer's eyes and the light emitted from the phosphor is visible. Cause the weakening.

  For this reason, in recent PDPs, as a measure for solving a decrease in contrast due to reflection of room light, the room light is prevented from entering the discharge cells constituting the PDP by improving the room light shielding rate on the front substrate. The method is adopted. For example, as shown in FIG. 5, a bus electrode, which has conventionally been composed of only one white layer mainly composed of silver or the like, is first coated with a black paste to form a black layer 16b, on which a white layer is formed. In this method, the layer 16a is laminated to form a bus electrode 16 composed of two black and white layers 16a and 16b (see, for example, Patent Document 1).

  A photocurable resin comprising a heat-resistant black pigment, an organic binder, a photopolymerizable monomer, a photopolymerization initiator, and organic beads as a material for forming a black film such as the black layer of the bus electrode. There has been proposed a front substrate for PDP in which a composition and a black layer are formed of the photocurable resin composition (see, for example, Patent Document 2). A photolithography method is used to form a black layer constituting a bus electrode made of the photocurable resin composition disclosed in Patent Document 2.

Specifically, first, a photocurable resin composition is applied to the entire surface of the front glass substrate on which the transparent electrode is formed, and dried to form a tack-free black layer. A photomask having a bus electrode pattern is superimposed on the formed black layer and exposed. Next, a highly conductive composition containing conductive powder such as Ag is applied to the entire surface of the black layer and dried to form a tack-free white layer (conductive layer). This is overlaid with a photomask having an exposure pattern of bus electrodes and exposed. Next, a non-exposed portion is removed by development with an aqueous alkali solution and baked to form a bus electrode composed of a black layer (lower layer) electrode and a white layer (upper layer) electrode on the transparent electrode of the windshield substrate. , A black matrix is formed. In the photolithography method, a so-called photosensitive black paste containing a photo-curable monomer having a photo-curing property is used as a material for the black layer. Here, “tack” is a value indicating the degree of adhesive strength.
JP 2004-63247 A (Claim 1) Japanese Patent Laying-Open No. 2005-8700 (Claims 1 and 4, specification [0052], FIG. 2)

  However, in Patent Documents 1 and 2, first, a black paste is applied to form a black layer, and then a white layer is stacked thereon to form a bus electrode. Therefore, the black and white two layers must be formed by different materials and different processes, respectively, and since the photolithography method is used as a method for forming the black layer, complicated processes such as coating, drying, exposure, development, and baking are required. You have to go through the manufacturing process.

  In addition, since the portions other than the exposed portions are removed in a post process in the photolithography method, the use efficiency of the paste material is extremely poor, and depending on the type of element contained in the paste material to be removed, the cost for the processing method, recycling, etc. Such a problem has also occurred.

  Therefore, the present invention has been made to solve the problems of such conventional techniques.

  An object of the present invention is to provide a conductive black paste composition capable of forming a bus electrode composed of a single black layer having both a shielding effect and high conductivity.

  Another object of the present invention is to provide a method of manufacturing a bus electrode using a conductive black paste composition capable of improving the utilization efficiency of a paste material.

  Still another object of the present invention is to provide a method of manufacturing a bus electrode using a conductive black paste composition that can improve the complexity of a conventional manufacturing process using a photolithography method and simplify the manufacturing process. It is in.

The invention according to claim 1 is a conductive black paste composition for forming a bus electrode on a windshield substrate constituting a plasma display panel, the composition comprising 1 to 10% by mass of black oxide powder and 1 to 10% by mass of sulfide powder, 1 to 25% by mass of glass powder, 35 to 85% by mass of metal powder, and the balance is an organic vehicle, and the average particle size of the black oxide powder Is a conductive black paste composition, wherein the black oxide powder has a specific surface area of 3 to 50 m ² / g.

In the invention according to claim 1, when the paste composition of the present invention contains each component in the above-mentioned range, the reaction layer composed of Ag ₂ S or CuS in which sulfide is generated in the vicinity of the interface with the substrate during firing is sufficient. Black color is obtained. Therefore, even if the content ratio of the metal powder is increased to ensure high conductivity and the content ratio of the black oxide powder is decreased, a sufficient shielding effect can be obtained by the combined use with the reaction layer of Ag ₂ S or CuS. It is done. As a result, the bus electrode, which has been conventionally composed of two layers of a black layer having a room light shielding effect and a white layer as a conductive layer, is formed by a single black layer having both a shielding effect and high conductivity. Can be formed. In addition, the sulfide powder itself used does not need to be black. In addition, by setting the average particle size and specific surface area of the black oxide powder within the above ranges, a fine and line-free pattern can be formed.

  The invention according to claim 2 is the invention according to claim 1, wherein the black oxide powder contains a metal element selected from the group consisting of Co, Cr, Cu, Mn, Fe and Ni. Or a conductive black paste composition that is a composite oxide containing two or more metal elements or a mixture thereof.

  The invention according to claim 3 is the invention according to claim 1, wherein the sulfide powder is one metal selected from the group consisting of Cu, Fe, Zn, Ag, Sb, Al, Co, Ni, and Sn. The conductive black paste composition is a metal sulfide containing an element, a composite sulfide containing two or more metal elements, or a mixture thereof.

  In the invention which concerns on Claim 3, since the said sulfide powder is used as a component of the electroconductive black paste composition of this invention, it is suitable for obtaining sufficient blackness in the formed bus electrode.

  The invention according to claim 4 is the invention according to claim 1, wherein the glass powder is selected from the group consisting of lead oxide, bismuth oxide, zinc oxide, boron oxide, silicon oxide, phosphorus oxide, calcium oxide and titanium oxide. In addition, the conductive black paste composition is a frit glass having a softening point of 450 to 550 ° C. containing one or more oxides.

  The invention according to claim 5 is the conductive black paste composition according to claim 1, wherein the metal powder is one or more metal powders selected from the group consisting of Au, Ag, Cu and Ni. It is a thing.

  As shown in FIGS. 3 and 4, the invention according to claim 6 is a coating of the conductive black paste composition according to any one of claims 1 to 5 on a substrate by an offset printing method or a screen printing method. And a bus electrode is formed by baking the coating film.

  In the invention which concerns on Claim 6, since the paste composition which uses a fine black oxide powder and sulfide powder is used, it can form a fine and pattern without line disorder. In addition, since the bus electrode is manufactured using the conductive black paste composition according to the present invention, it is not necessary to form the two layers of black and white by different materials and different processes, so that the manufacturing process can be simplified. In the photolithography method used in the conventional manufacturing process, it is necessary to apply the paste composition to the entire desired surface and then expose it to remove unnecessary portions and discard them. However, since the coating method is applied by the offset printing method or the screen printing method in the production method of the present invention, it is only necessary to apply the paste composition only to the necessary portion, so that the material to be used is not wasted and the utilization efficiency of the paste material is improved. Can be improved. Further, the complexity of the manufacturing process such as coating, drying, exposure, development, and baking when using the photolithography method can be improved, and the manufacturing process can be simplified.

As described above, according to the conductive black paste composition of the present invention, the paste composition is 1 to 10% by mass of black oxide powder, 1 to 10% by mass of sulfide powder, and 1 to 25% by mass. % Of glass powder, 35 to 85% by weight of metal powder, and the balance being an organic vehicle, the reaction layer of Ag ₂ S or CuS in which sulfide is generated near the interface with the substrate during firing is sufficient. Black color is obtained. Therefore, even if the content ratio of the metal powder is increased to ensure high conductivity and the content ratio of the black oxide powder is decreased, a sufficient shielding effect can be obtained by the combined use with the reaction layer of Ag ₂ S or CuS. It is done. Thereby, the bus electrode comprised from the single black layer which has both the shielding effect and high electroconductivity can be formed. By forming a bus electrode with a single black layer that has both shielding effect and high conductivity, it is not necessary to form two layers of black and white with different materials and different processes as in the past, so manufacturing The process can be simplified. In addition, a fine black oxide powder having an average particle size of 0.05 to 0.5 μm and a specific surface area of 3 to 50 m ² / g is included as a component, so that a fine and line-free pattern is formed. be able to. Furthermore, since the offset printing method or the screen printing method is used in the present invention, the use efficiency of the paste material can be improved as compared with the case of using the photolithography method, and the application, drying, and the like when using the photolithography method, The complexity of the manufacturing process such as exposure, development, and baking can be improved, and the manufacturing process can be simplified.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings.

As shown in FIG. 1, the conductive black paste composition of the present invention is used to form bus electrodes 16 on a windshield substrate 11 constituting the PDP 10. The conductive black paste composition of the present invention comprises 1 to 10% by weight black oxide powder, 1 to 10% by weight sulfide powder, 1 to 25% by weight glass powder, and 35 to 85% by weight. It is comprised so that metal powder and the remainder may contain an organic vehicle. The average particle diameter of the black oxide powder is in the range of 0.05 to 0.5 μm, and the specific surface area of the black oxide powder is in the range of 3 to 50 m ² / g. In the present specification, the average particle diameter is measured with a laser diffraction / scattering particle size distribution analyzer (LA-950, manufactured by Horiba, Ltd.), and the 50% average particle diameter (D ₅₀ ) calculated using the particle diameter standard as the number. ). The number-based average particle diameter measured by the laser diffraction / scattering particle size distribution measuring apparatus is the value of any 50 particles in an image observed with a scanning electron microscope (S-4300SE and S-900 manufactured by Hitachi High-Technologies). It almost coincides with the average particle diameter when the particle diameter is actually measured. The specific surface area is a value obtained by calculating the specific surface area after measuring the amount of adsorption using N ₂ gas by the gas adsorption method (BET 3-point method) using a gas adsorption amount measuring device (AUTOSORB-1 manufactured by Quantachrome).

By making each component contained in the conductive black paste composition of the present invention within the above range, it is composed of a single black layer having both a shielding effect and high conductivity as shown in FIG. A bus electrode can be formed. In order to obtain a black color for obtaining a sufficient shielding effect, it is necessary to increase the content ratio of the black oxide powder. However, since the black oxide powder is a non-conductive powder, the content ratio of the black oxide powder is Increasing the value decreases the conductivity. On the other hand, if the content ratio of the black oxide powder is decreased and the ratio of the metal powder is increased in order to obtain high conductivity, the blackness is lowered and a sufficient shielding effect cannot be obtained. However, as shown in FIG. 2, according to the conductive black paste composition of the present invention, the sulfide contained as a component causes Ag ₂ S or the vicinity of the interface with the substrate 11 where oxygen is not sufficiently taken in during firing. A black reaction layer 25 made of CuS is formed. Therefore, even if the content ratio of the metal powder is increased and the content ratio of the black oxide powder is decreased in order to obtain high conductivity, a sufficient shielding effect can be obtained. Ag ₂ S and CuS itself are poorly conductive materials, but are present only in the layer near the interface with the substrate 11, so that a shielding effect can be obtained without lowering the electrical resistance of the surface of the bus electrode 16. It is done.

  As a result, as shown in FIG. 5, the conventional bus is composed of two layers of a black layer 16a for improving the shielding rate of indoor light and a white layer 16b which is a conductive layer mainly composed of silver or the like. The electrode 16 can be formed of a single black layer having both a shielding effect and high conductivity as shown in FIG. The reason why the content of the black oxide powder is in the range of 1 to 10% by mass is that if the bus electrode is formed below the lower limit, sufficient black color cannot be obtained in portions other than the vicinity of the interface with the substrate. This is because the rate decreases, and if the upper limit is exceeded, a large amount of non-conductive powder is contained, so that sufficient conductivity as a bus electrode cannot be obtained. The reason why the content of the sulfide powder is within the range of 1 to 10% by mass is that if the bus electrode is less than the lower limit value, the reaction layer having a sufficiently black color in the vicinity of the interface with the substrate cannot be obtained. This is because if the ratio exceeds the upper limit, a large amount of non-conductive sulfide that does not participate in the formation of the reaction layer is present in the vicinity of the surface of the bus electrode after firing, resulting in a decrease in conductivity. The reason why the content of the glass powder is within the range of 1 to 25% by mass is that if it is less than the lower limit value, the presence of the glass powder spreading in a matrix is too small and the adhesion to the substrate is deteriorated, exceeding the upper limit value. This is because a large amount of non-conductive powder component is contained with respect to the conductive powder component, and therefore sufficient conductivity cannot be obtained. The reason why the content of the metal powder is within the range of 35 to 85% by mass is that sufficient conductivity cannot be obtained if the content is less than the lower limit value, and if the content exceeds the upper limit value, white color due to reflection of metallic luster increases and blackness is increased. It is because it falls. Among these, the content rate of the black oxide powder is 5 to 10% by mass, the content rate of the sulfide powder is 2 to 8% by mass, the content rate of the glass powder is 5 to 20% by mass, and the content rate of the metal powder is 45 to 5%. It is preferably within the range of 75% by mass.

Further, by using a fine black oxide powder having an average particle diameter and a specific surface area within the above ranges, a fine pattern free from line disturbance can be formed. The average particle diameter of the black oxide powder is 0.05 to 0.5 μm and the specific surface area is in the range of 3 to 50 m ² / g because the average particle diameter is less than the lower limit value or the specific surface area is the upper limit value. If it exceeds 1, the specific surface area becomes too large, the fluidity of the solvent, resin, etc. in the paste deteriorates, resulting in a problem of a paste composition having a high thixotropic property. On the other hand, when the average particle size is larger than the upper limit value or the specific surface area is less than the lower limit value, the particle size is too large, so that the line disturbance becomes large and a fine pattern cannot be formed. Among these, the average particle diameter of the black oxide powder is preferably in the range of 0.05 to 0.3 μm, and the specific surface area is preferably in the range of 10 to 45 m ² / g.

The black oxide powder is a metal oxide containing one kind of metal element selected from the group consisting of Co, Cr, Cu, Mn, Fe and Ni, a composite oxide containing two or more kinds of metal elements, or a mixture thereof. It is preferable that it is. Among these, Co ₃ O ₄ powder, Fe, Mn, Cu composite oxide or Cu, Cr, Mn composite oxide are particularly preferable.

  The sulfide powder is a metal sulfide containing one metal element selected from the group consisting of Cu, Fe, Zn, Ag, Sb, Al, Co, Ni, and Sn, or a composite containing two or more metal elements. It is preferably a sulfide or a mixture thereof. Among these, CuS, FeS, and AgS are particularly preferable because they are highly reactive and suitable for obtaining a high black color. Moreover, it is preferable to use a sulfide powder having an average particle size as small as possible, and among these, it is preferable to be within a range of 0.05 to 1.0 μm. If the average particle diameter of the sulfide powder is within the above range, it is suitable for forming a fine pattern without line disturbance.

The glass powder contains one or more oxides selected from the group consisting of lead oxide, bismuth oxide, zinc oxide, boron oxide, silicon oxide, aluminum oxide, phosphorus oxide, calcium oxide and titanium oxide, 400 to 400 A frit glass having a softening point of 550 ° C. is preferable. The softening point of the frit glass is particularly preferably 450 to 550 ° C. The reason why the softening point is within the above range is that, in the frit glass having a softening point less than the lower limit, the glass powder hinders binder removal of the binder resin constituting the organic vehicle in the paste composition. The bus electrode formed using the paste composition tends to increase the resistance value. Moreover, in the frit glass whose softening point exceeds the upper limit, the glass powder tends to hardly give a sufficient anchor between the glass substrate. The average particle size of the glass powder is preferably 0.05 to 1.0 μm. If it is less than 0.05 μm, a bus electrode having excellent adhesion to the substrate can be formed, but at present, it takes too much cost and time to obtain a glass powder having a thickness of less than 0.05 μm. On the other hand, when the thickness exceeds 1.0 μm, the glass is unevenly distributed, so that the glass powder is softened and becomes colorless and transparent, and then there is a tendency that a portion having a low shielding rate is generated. Specifically, PbO—B ₂ O ₃ —SiO ₂ , ZnO—B ₂ O ₃ —SiO ₂ , PbO—B ₂ O ₃ —SiO ₂ —Al ₂ O ₃ , PbO—ZnO—B ₂ O ₃ —SiO ₂ , PbO—B ₂ O ₃ —SiO ₂ —Al ₂ O ₃ —ZnO, PbO—B ₂ O ₃ —SiO ₂ —CaO, B ₂ O ₃ —ZnO—Bi ₂ O ₃ , B ₂ O ₃ —Bi ₂ O ₃ , B ₂ O ₃ —ZnO, Bi ₂ O ₃ —B ₂ O ₃ —SiO ₂ , ZnO—P ₂ O ₅ —SiO ₂ , P ₂ O ₅ —B ₂ O ₃ —Al ₂ O ₃ , ZnO— Combinations such as P ₂ O ₅ —TiO ₂ can be mentioned.

  The metal powder is preferably one or more metal powders selected from the group consisting of Au, Ag, Cu and Ni. Among these, Ag powder is particularly preferable because high conductivity is obtained. The average particle size of the metal powder is preferably in the range of 0.1 to 0.7 μm. If the average particle diameter of the metal powder is within the above range, it is suitable for forming a fine pattern without line disturbance.

  It is preferable to use an organic vehicle prepared by dissolving an alkali-soluble resin in an organic solvent. A dispersant for improving dispersibility of black oxide powder, sulfide powder, glass powder and metal powder, a viscosity modifier for adjusting paste viscosity, and the like are added as necessary.

  The bus electrode manufacturing method of the present invention is characterized in that a bus electrode is formed on a substrate by an offset printing method or a screen printing method using the conductive black paste composition. Since the conductive black paste composition of the present invention uses fine black oxide powder and sulfide powder, it is possible to form a fine pattern without line disturbance. Conventionally, a bus electrode composed of two layers, a black layer for improving the shielding rate of room light and a white layer which is a conductive layer mainly composed of silver or the like, has been formed by different materials and different processes. However, since the bus electrode can be formed with a single black layer by using the conductive black paste composition according to the present invention, the manufacturing process can be greatly simplified. Furthermore, since the coating method is applied by the offset printing method or the screen printing method in the production method of the present invention, it is only necessary to apply the paste composition only to the necessary portion, so that the material used is not wasted and the conventional photolithography method is used. The use efficiency of the paste material can be improved as compared with the case where it is used. Further, the complexity of the manufacturing process such as coating, drying, exposure, development, and baking when using the photolithography method can be improved, and the manufacturing process can be simplified.

  Next, a method for forming a PDP front substrate using the bus electrode manufacturing method of the present invention will be described.

First, a windshield substrate 11 as shown in FIG. 3A is prepared, and a transparent electrode 23 is formed on the windshield substrate 11 as shown in FIG. The transparent electrode 23 formed here is formed of a transparent material that is necessary for plasma discharge and does not hinder light emission. Specifically, the transparent electrode 23 uses an oxide film such as ITO (Indium Tin Oxide) or SnO _2, and is formed by a vacuum film forming method such as sputtering or vapor deposition or a CVD (Chemical Vapor Deposition) method.

  Next, as shown in FIG. 3C, the conductive black paste composition of the present invention is formed on the formed transparent electrode 23, and the coating film 15 is formed on the windshield substrate 11 by the offset printing method or the screen printing method. To do. In the method of the present invention, since a paste composition containing fine black oxide powder and sulfide powder is used, it is possible to form a coating film that is fine and free from line disturbance.

Next, as shown in FIG. 3D, the coating film 15 formed on the windshield substrate 11 is baked at a temperature of 500 to 600 ° C. At the time of this firing, as shown in FIG. 2, a black reaction layer 25 made of Ag ₂ S or CuS is formed near the interface with the substrate where oxygen is not sufficiently taken in. Thereby, the bus electrode 16 comprised from the single black layer which has both the shielding effect and the high electroconductivity by metal powder is formed.

  Next, as shown in FIG. 3E, a transparent dielectric layer 21 is formed on the entire surface of the windshield substrate 11 so as to cover the transparent electrode 23 and the bus electrode 16. The transparent dielectric layer 21 is formed in order to provide a memory function by forming wall charges on the surface of the dielectric layer during electrode protection and discharging. The transparent dielectric layer 21 is formed on the bus electrode 16 so as to have a thickness of 20 to 40 μm.

  Next, as shown in FIG. 4A, a black paste 24 is formed on the formed transparent dielectric layer 21 by applying and baking a black paste composition by an offset printing method. By forming the black stripe 24, the external light reflectance is reduced and the contrast is improved.

Next, as shown in FIG. 4B, the color filter 22 is formed on the transparent dielectric layer 21 so as to have the same height as the black stripe 24. Subsequently, as shown in FIG. 4C, the transparent dielectric layer 21 is formed on the color filter 22 and the black stripe 24. Further, as shown in FIG. 4D, a protective film 19 is formed on the transparent dielectric layer 21.
The protective film 19 is formed when the dielectric layer is damaged by ion bombardment due to discharge and the panel life is shortened, and the efficiency of secondary electron emission necessary for plasma discharge is low, and the discharge voltage becomes high. This is to prevent this. The protective film 19 is made of MgO and can be formed by electron beam evaporation, ion plating, or sputtering.

  As described above, the front substrate for PDP is obtained through the steps of FIGS. 3A to 4D.

  Next, examples of the present invention will be described in detail together with comparative examples.

<Example 1>
As shown in the following Table 1, as a black oxide powder, a Co ₃ O ₄ powder having an average particle diameter of 0.2 μm and a specific surface area of 28 m ² / g, a sulfide powder as an FeS powder, and a glass powder as a PbO—B ₂ O ₃ —SiO ₂ , Ag powder as metal powder, and organic vehicle were prepared. Next, 4% by mass of Co ₃ O ₄ powder, ₃ % by mass of FeS powder, 15% by mass of glass powder, 50% by mass of Ag powder, and 18% by mass of an alkali-soluble resin and 10% by mass of a solvent as an organic vehicle are obtained by planetary stirring. Premixed. Furthermore, this mixture was sufficiently mixed and dispersed with three rolls to obtain a conductive black paste composition.

  The organic vehicle was prepared by dissolving an alkali-soluble resin in an organic solvent. Additives such as a dispersant and a viscosity modifier are appropriately added to the organic vehicle according to the conductive black paste composition to be produced. The dispersant was appropriately added to improve the dispersibility of the black oxide powder, glass powder and metal powder, and the viscosity modifier was appropriately added to adjust the viscosity of the paste.

<Example 2>
As shown in the following Table 1, Fe, Mn, Cu composite oxide powder having an average particle size of 0.1 μm and specific surface area of 32 m ² / g as black oxide powder, CuS powder as sulfide powder, and Bi ₂ as glass powder. O ₃ —B ₂ O ₃ —SiO ₂ , Ag powder as a metal powder, and an organic vehicle were prepared. Next, 7% by mass of Fe, Mn, Cu composite oxide powder, 2% by mass of CuS powder, 10% by mass of glass powder, 63% by mass of Ag powder, and 12% by mass of alkali-soluble resin and 6% by mass of solvent as an organic vehicle. Thus, a conductive black paste composition was obtained by the same method as in Example 1.

<Example 3>
As shown in Table 1, Cu, Cr, Co composite oxide powder having an average particle diameter of 0.3 μm and a specific surface area of 21 m ² / g as black oxide powder, AgS powder as sulfide powder, and Bi ₂ as glass powder. O ₃ —B ₂ O ₃ —SiO ₂ , Ag powder as a metal powder, and an organic vehicle were prepared. Next, 5% by mass of Cu, Cr, Co composite oxide powder, 3% by mass of AgS powder, 12% by mass of glass powder, 50% by mass of Ag powder, and 20% by mass of an alkali-soluble resin and 10% by mass of a solvent as an organic vehicle. Thus, a conductive black paste composition was obtained by the same method as in Example 1.

<Example 4>
As shown in Table 1, Co ₃ O ₄ powder having an average particle size of 0.25 μm and specific surface area of 15 m ² / g as black oxide powder, CuS powder as sulfide powder, and Bi ₂ O ₃ —B as glass powder. ₂ O ₃ —SiO ₂ , Ag powder as metal powder, and organic vehicle were prepared. Next, ₃ % by mass of Co ₃ O ₄ powder, 6% by mass of CuS powder, 3% by mass of glass powder, 65% by mass of Ag powder, and 15% by mass of an alkali-soluble resin and 8% by mass of a solvent as an organic vehicle, A conductive black paste composition was obtained in the same manner as in Example 1.

<Comparative Example 1>
As shown in Table 1, Co ₃ O ₄ powder having an average particle size of 0.25 μm and a specific surface area of 15 m ² / g as black oxide powder, Bi ₂ O ₃ —B ₂ O ₃ —SiO ₂ as glass powder, Ag powder and organic vehicle were prepared as metal powder. Next, the same method as in Example 1 with 5% by mass of Co ₃ O ₄ powder, 15% by mass of glass powder, 50% by mass of Ag powder, and 20% by mass of an alkali-soluble resin and 10% by mass of a solvent as an organic vehicle. Thus, a conductive black paste composition was obtained. That is, the paste composition of Comparative Example 1 does not contain sulfide powder.

<Comparative example 2>
As shown in the following Table 1, Fe, Mn, Cu composite oxide powder having an average particle size of 0.6 μm and a specific surface area of 12 m ² / g as black oxide powder, and Bi ₂ O ₃ —B ₂ O ₃ as glass powder. —SiO ₂ , Ag powder as metal powder, and organic vehicle were prepared. Next, Fe, Mn, Cu composite oxide powder 5% by mass, glass powder 15% by mass, Ag powder 50% by mass, and as an organic vehicle, an alkali-soluble resin 20% by mass and a solvent 10% by mass. 1 was used to obtain a conductive black paste composition. That is, the paste composition of Comparative Example 2 does not contain sulfide powder.

<Comparative Example 3>
As shown in the following Table 1, as a black oxide powder, a Co ₃ O ₄ powder having an average particle size of 0.3 μm and a specific surface area of 21 m ² / g, a CuS powder as a sulfide powder, and a PbO—B ₂ O ₃ as a glass powder. —SiO ₂ , Ag powder as metal powder, and organic vehicle were prepared. Next, 6.9% by mass of Co ₃ O ₄ powder, 0.1% by mass of CuS powder, 15% by mass of glass powder, 50% by mass of Ag powder, and 18% by mass of alkali-soluble resin and 10% by mass of solvent as an organic vehicle. Thus, a conductive black paste composition was obtained by the same method as in Example 1.

<Comparative example 4>
As shown in Table 1 below, Fe, Mn, Cu composite oxide powder having an average particle size of 0.25 μm and a specific surface area of 15 m ² / g as black oxide powder, CuS powder as sulfide powder, and Bi ₂ as glass powder. O ₃ —B ₂ O ₃ —SiO ₂ , Ag powder as a metal powder, and an organic vehicle were prepared. Next, 4% by mass of Fe, Mn, Cu composite oxide powder, 15% by mass of CuS powder, 10% by mass of glass powder, 53% by mass of Ag powder, and 12% by mass of alkali-soluble resin and 6% by mass of solvent as an organic vehicle. Thus, a conductive black paste composition was obtained by the same method as in Example 1.

<Comparative Example 5>
As shown in the following Table 1, as a black oxide powder, a Co ₃ O ₄ powder having an average particle diameter of 0.5 μm and a specific surface area of 10 m ² / g, a sulfide powder, a CuS powder, and a glass powder as a PbO—B ₂ O ₃ —SiO ₂ , Ag powder as metal powder, and organic vehicle were prepared. Next, 15% by mass of Co ₃ O ₄ powder, 5% by mass of CuS powder, 15% by mass of glass powder, 35% by mass of Ag powder, and 20% by mass of an alkali-soluble resin as an organic vehicle and 10% by mass of a solvent, A conductive black paste composition was obtained in the same manner as in Example 1.

<Comparative Example 6>
As shown in the following Table 1, Fe, Mn, Cu composite oxide powder having an average particle size of 0.2 μm and specific surface area of 32 m ² / g as black oxide powder, CuS powder as sulfide powder, and Bi ₂ as glass powder. O ₃ —B ₂ O ₃ —SiO ₂ , Ag powder as a metal powder, and an organic vehicle were prepared. Next, 0.1% by mass of Fe, Mn, Cu composite oxide powder, 5% by mass of CuS powder, 10% by mass of glass powder, 63% by mass of Ag powder, 15% by mass of alkali-soluble resin as an organic vehicle, and solvent 6 A conductive black paste composition was obtained in the same manner as in Example 1 at a ratio of 0.9 mass%.

<Comparative Example 7>
As shown in the following Table 1, Fe, Mn, Cu composite oxide powder having an average particle size of 0.6 μm and a specific surface area of 12 m ² / g as black oxide powder, CuS powder as sulfide powder, PbO— as glass powder B ₂ O ₃ —SiO ₂ , Ag powder as metal powder, and organic vehicle were prepared. Next, 2% by mass of Fe, Mn, Cu composite oxide powder, 2% by mass of CuS powder, 0.1% by mass of glass powder, 90% by mass of Ag powder, 2.9% by mass of an alkali-soluble resin as an organic vehicle, and A conductive black paste composition was obtained by the same method as in Example 1 at a ratio of 3.0% by mass of the solvent.

<Comparative Example 8>
As shown in the following Table 1, Fe, Mn, Cu composite oxide powder having an average particle size of 0.25 μm and a specific surface area of 15 m ² / g as black oxide powder, CuS powder as sulfide powder, PbO— as glass powder B ₂ O ₃ —SiO ₂ , Ag powder as metal powder, and organic vehicle were prepared. Next, 4% by mass of Fe, Mn, Cu composite oxide powder, 6% by mass of CuS powder, 30% by mass of glass powder, 30% by mass of Ag powder, and 20% by mass of alkali-soluble resin and 10% by mass of solvent as an organic vehicle. Thus, a conductive black paste composition was obtained by the same method as in Example 1.

<Comparative Example 9>
As shown in the following Table 1, as a black oxide powder, a Co ₃ O ₄ powder having an average particle size of 0.7 μm and a specific surface area of 2 m ² / g, a sulfide powder such as a CuS powder, and a glass powder as Bi ₂ O ₃ —B ₂ O ₃ —SiO ₂ , Ag powder as metal powder, and organic vehicle were prepared. Next, 5% by mass of Co ₃ O ₄ powder, 5% by mass of CuS powder, 10% by mass of glass powder, 60% by mass of Ag powder, and 12% by mass of an alkali-soluble resin and 8% by mass of a solvent as an organic vehicle, A conductive black paste composition was obtained in the same manner as in Example 1.

<Comparative Example 10>
As shown in the following Table 1, as a black oxide powder, Co ₃ O ₄ powder having an average particle diameter of 0.006 μm and a specific surface area of 65 m ² / g, sulfide powder as CuS powder, and glass powder as Bi ₂ O ₃ —B ₂ O ₃ —SiO ₂ , Ag powder as metal powder, and organic vehicle were prepared. Next, 5% by mass of Co ₃ O ₄ powder, 5% by mass of CuS powder, 10% by mass of glass powder, 60% by mass of Ag powder, and 12% by mass of an alkali-soluble resin and 8% by mass of a solvent as an organic vehicle, A conductive black paste composition was obtained in the same manner as in Example 1.

＜比較試験１＞
実施例１〜４及び比較例１〜１０で得られた導電性黒色ペースト組成物を用いて、以下のオフセット印刷性、最小線幅、保存安定性、抵抗値についての評価を行った。その結果を次の表３に示す。

<Comparison test 1>
Using the conductive black paste compositions obtained in Examples 1 to 4 and Comparative Examples 1 to 10, the following offset printability, minimum line width, storage stability, and resistance value were evaluated. The results are shown in Table 3 below.

  (1) Offset printability: Transferability when the conductive black paste composition was printed on a glass substrate with an offset printing machine (manufactured by JEOL Ltd.) was evaluated as offset printability. When the conductive black paste composition is transferred from the blanket onto the glass substrate, the line shape is not disturbed and transferred 100%, and there is no residual paste on the blanket. Although it was evaluated as “good” and some blurring and disturbance were confirmed in the line shape, there was no residual paste composition on the blanket and 100% transfer was possible. An evaluation of “impossible” was made when spots or defects were confirmed, or when paste that could not be transferred remained on the blanket.

  (2) Minimum line width: The line width capable of offset printing is represented by four line widths of 50 μm, 70 μm, 100 μm, and 150 μm, and this line width is defined as the minimum line width.

  Next, the conductive black paste compositions obtained in Examples 1 to 4 and Comparative Examples 1 to 10 were applied on a glass substrate by a screen printing method, and this coating film was baked at 580 ° C. for 30 minutes to obtain a bus electrode. Formed. About the formed bus electrode, the following blackness, adhesiveness, and electroconductivity were evaluated. The results are shown in Table 2 below.

  (3) Blackness: The blackness of the formed bus electrode was measured using a color computer (manufactured by Suga Test Instruments Co., Ltd.). Specifically, the L value of the Lab notation method by the CIELab display method was obtained. Note that the smaller the L value, the higher the blackness.

  (4) Adhesiveness: For the formed bus electrode, the adhesiveness of the bus electrode was evaluated by a cross-cut tape test method based on JIS-K5400. A specific evaluation of the adhesion is a “good” evaluation when the bus electrode on the tape side is not transferred and the bus electrode is 100% adhered on the glass substrate when the grid eye tape test is performed. When the bus electrode adheres to both the tape and the glass substrate due to internal destruction, it was evaluated as “Yes”. Many bus electrodes adhered to the tape side, and the glass substrate was observed at the interface after thinning. The evaluation was “impossible”.

  (5) Conductivity: The line resistance between two points of the pattern was measured with a multimeter in a state where an interval of about 10 cm was provided in the longitudinal direction of the bus electrode formed with a width of about 100 μm.

表２から明らかなように、実施例１〜４と比較例１，２を比較すると、硫化物を含まない比較例１，２では、Ｌ値及び抵抗値が大きくなり、室内光の遮蔽に十分な黒色度及びバス電極としての十分な導電性が得られなかった。このことから、硫化物粉末を使用することが効果的であることが確認された。実施例１〜４と比較例３，４を比較すると、硫化物粉末の含有割合が１質量％未満の比較例３では、Ｌ値が大きくなり室内光の遮蔽に十分な黒色度が得られなかった。一方、硫化物粉末の含有割合が１０質量％を越える比較例４では、十分な導電性が得られなかった。このことから、硫化物粉末の含有割合は、１〜１０質量％の範囲内が効果的であることが確認された。実施例１〜４と比較例５，６を比較すると、黒色酸化物粉末の含有割合が１０質量％を越える比較例５ではＬ値が小さくなり高い黒色度が得られたものの、抵抗値が大きくなりすぎて十分な導電性が得られなかった。一方、黒色酸化物粉末の含有割合が１質量％未満である比較例６では、高い導電性は得られたものの、Ｌ値が大きくなり室内光の遮蔽に十分な黒色度が得られなかった。このことから、黒色酸化物粉末の含有割合は１〜１０質量％の範囲内が効果的であることが確認された。実施例１〜４と比較例７，８を比較すると、ガラス粉末の含有割合が１質量％未満で、金属粉末の含有割合が８５質量％を越える比較例７では、高い導電性は得られたものの、Ｌ値が大きくなり室内光の遮蔽に十分な黒色度が得られなかった。一方、ガラス粉末の含有割合が２５質量％を越え、金属粉末の含有割合が３５質量％未満の比較例８では、抵抗値が大きくなりすぎて十分な導電性が得られなかった。このことから、ガラス粉末の含有割合は１〜２５質量％、金属粉末の含有割合は３５〜８５質量％の範囲にすることが効果的であることが確認された。実施例１〜４と比較例９，１０を比較すると、平均粒径が０．５μｍを越え、比表面積が３ｍ²／ｇ未満の比較例９では、オフセット印刷性が「可」の評価にとどまった。一方、平均粒径が０．０５μｍ未満で、比表面積が５０ｍ²／ｇを越える比較例１０では、密着性が不可となった。このことから、黒色酸化物粉末の平均粒径は０．０５〜０．５μｍ、かつ黒色酸化物粉末の比表面積は３〜５０ｍ²／ｇの範囲にすることが効果的であることが確認された。

As is clear from Table 2, when Examples 1 to 4 and Comparative Examples 1 and 2 are compared, Comparative Examples 1 and 2 not containing sulfide have large L values and resistance values, which are sufficient for shielding indoor light. The blackness and sufficient conductivity as a bus electrode could not be obtained. From this, it was confirmed that it is effective to use sulfide powder. When Examples 1-4 and Comparative Examples 3 and 4 are compared, in Comparative Example 3 in which the content ratio of the sulfide powder is less than 1% by mass, the L value increases and blackness sufficient for shielding indoor light cannot be obtained. It was. On the other hand, in Comparative Example 4 in which the content ratio of the sulfide powder exceeds 10% by mass, sufficient conductivity was not obtained. From this, it was confirmed that the content of the sulfide powder is effective within the range of 1 to 10% by mass. When Examples 1-4 and Comparative Examples 5 and 6 are compared, in Comparative Example 5 in which the content ratio of the black oxide powder exceeds 10% by mass, the L value is small and high blackness is obtained, but the resistance value is large. Thus, sufficient conductivity was not obtained. On the other hand, in Comparative Example 6 in which the content of the black oxide powder was less than 1% by mass, high conductivity was obtained, but the L value was large, and blackness sufficient for shielding room light was not obtained. From this, it was confirmed that the content ratio of the black oxide powder is effective within the range of 1 to 10% by mass. When Examples 1-4 and Comparative Examples 7 and 8 were compared, high conductivity was obtained in Comparative Example 7 in which the glass powder content was less than 1% by mass and the metal powder content was greater than 85% by mass. However, the L value increased and blackness sufficient to shield room light could not be obtained. On the other hand, in Comparative Example 8 in which the content ratio of the glass powder exceeds 25% by mass and the content ratio of the metal powder is less than 35% by mass, the resistance value is too large to obtain sufficient conductivity. From this, it was confirmed that it is effective to set the content ratio of the glass powder to 1 to 25 mass% and the content ratio of the metal powder to 35 to 85 mass%. Comparing Examples 1 to 4 and Comparative Examples 9 and 10, in Comparative Example 9 in which the average particle diameter exceeds 0.5 μm and the specific surface area is less than 3 m ² / g, the offset printability is evaluated as “good”. It was. On the other hand, in Comparative Example 10 in which the average particle size was less than 0.05 μm and the specific surface area exceeded 50 m ² / g, adhesion was not possible. From this, it was confirmed that it is effective to make the average particle diameter of the black oxide powder 0.05 to 0.5 μm and the specific surface area of the black oxide powder 3 to 50 m ² / g. It was.

The figure which shows the discharge cell of PDP in which the bus electrode of this invention is comprised with a single black layer. The figure which showed typically the cross section of the bus electrode formed using the electroconductive black paste composition of this invention. The figure which shows the front | former stage of the manufacturing process of the front substrate for PDP of this invention. The figure which shows the back | latter stage of the manufacturing process of the front substrate for PDP of this invention. The figure which shows the discharge cell of PDP in which the conventional bus electrode is comprised by two layers, a black layer and a white layer.

Explanation of symbols

10 PDP
11 Windshield substrate 16 Bus electrode

Claims (6)

A conductive black paste composition for forming a bus electrode on a windshield substrate constituting a plasma display panel,
The composition is 1 to 10% by weight black oxide powder, 1 to 10% by weight sulfide powder, 1 to 25% by weight glass powder, 35 to 85% by weight metal powder, and the balance is organic. The black oxide powder has an average particle size of 0.05 to 0.5 μm, and the black oxide powder has a specific surface area of 3 to 50 m ² / g. Black paste composition.   Black oxide powder is a metal oxide containing one metal element selected from the group consisting of Co, Cr, Cu, Mn, Fe and Ni, or a composite oxide containing two or more metal elements, or a mixture thereof The conductive black paste composition according to claim 1.   The sulfide powder is a metal sulfide containing one metal element selected from the group consisting of Cu, Fe, Zn, Ag, Sb, Al, Co, Ni and Sn, or a composite sulfide containing two or more metal elements The conductive black paste composition according to claim 1, which is a product or a mixture thereof.   The glass powder has a softening point of 450 to 550 ° C. containing one or more oxides selected from the group consisting of lead oxide, bismuth oxide, zinc oxide, boron oxide, silicon oxide, phosphorus oxide, calcium oxide and titanium oxide. The conductive black paste composition according to claim 1, which is a frit glass.   The conductive black paste composition according to claim 1, wherein the metal powder is one or more metal powders selected from the group consisting of Au, Ag, Cu and Ni.   A conductive black paste composition according to any one of claims 1 to 5 is coated on a substrate by an offset printing method or a screen printing method, and the coating film is baked to form a bus electrode. A method for manufacturing a bus electrode.

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