WO2009143685A1

WO2009143685A1 - Black conductive paste and plasma display using the same

Info

Publication number: WO2009143685A1
Application number: PCT/CN2008/073258
Authority: WO
Inventors: 曹建
Original assignee: 四川虹欧显示器件有限公司
Priority date: 2008-05-29
Filing date: 2008-11-28
Publication date: 2009-12-03
Also published as: CN101593570A; CN101593570B

Abstract

A black conductive paste and a plasma display using the same are provided, the conductive paste comprises inorganic powder and organic component which is often used to form electrodes of a display panel, the inorganic powder is composed of glass powder and conductive metal powder, the average particle diameter of the metal powder is 10 to 1000nm, particularly not more than 800nm, and more particularly not more than 380nm.When the conductive metal is silver, the particle diameter of the metal powder is not less than 14nm.With respect to the total weight of the inorganic powder composed of the metal powder and the glass powder, the metal powder is 10-95% by weight.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a black conductive paste for a plasma display, and a plasma display using the same, and a method of fabricating the same, in particular, a black conductive paste Plasma display and method of manufacturing the same. BACKGROUND OF THE INVENTION In the production of plasma displays, in order to improve display contrast, it is necessary to reduce the reflection of external light from the front panel. In order to reduce the reflection of external light, the best method is to form a black layer having a low light transmittance and a low reflectance between the upper side of the transparent electrode on the front panel and the pair of discharge electrodes, which is black when viewed from the front of the display. In the slurry for forming a black layer, generally, a cerium oxide or a cerium-containing multi-metal oxide (as disclosed in the patents US Pat. No. 5,851, 732 A, US Pat. No. 6,075, 513 A, US Pat. An oxide of iron, cobalt, chromium, manganese, copper, and mixtures thereof, as disclosed in the patents CN02157439.1, CN03104467.0, CN200610082025.6, US20020096666A1, etc., and mixtures thereof (such as in the patents US6555594B1, US6132937A, US6793850B2, US20020096666A1, CN02157439.1, CN03104467.0, CN200610082025.6, US6103452A, etc.) or blackened (as disclosed in the patent CN01823762.2, etc.), etc. as a black colorant, in which these bismuth oxides exhibit better In addition to the coloring properties, the rest of the coloring performance is not ideal, and the price of cerium-containing oxide is very high. In addition, the black layer using oxide or carbon black as a coloring agent is poor in conductivity, and the black bus electrode made of them has low electrical conductivity, and it is necessary to prepare a high-conductivity bus electrode on the black bus electrode to prepare a good electrode. Conductive and high contrast bus electrodes. Thus, at least two printing and drying processes are required to make the bus electrodes. 1 is a schematic structural view of a prior art plasma display, and FIG. 2 is a schematic structural view of a front panel of a prior art plasma display. On the front glass substrate 5, an ITO or SnO ₂ film was first formed by ion sputtering, and then an ITO or SnO ₂ transparent electrode 1 having a thickness of about 100 nm was formed by photolithography. Forming a thickness on the transparent electrode 1 by screen printing or photosensitive lithography Several meters of bus electrodes 10 and 7. A transparent dielectric layer 8 of 10 - 30 μm thick is formed on the bus electrode 10 ( 7 ) by screen printing, and an MgO of about 0.6 μm thickness is formed on the transparent dielectric layer 8 by electron beam evaporation. Protective layer 11. Pairs of scanning and sustaining electrodes are formed by screen printing or photolithography to form black bars 9 having a thickness of 1 to 24 meters to improve display image contrast. The black strips 9 and the black bus electrodes 10 may be formed separately or in one time. On the other hand, referring to FIG. 1, on the rear glass substrate 6, the address electrode 2 is first formed by printing or photolithography, and then the white back plate medium 3 having a thickness of about 20 μm is printed and sintered, and then sprayed. The method of photolithography or etching forms a strip-shaped barrier structure 4, and a discharge space is partitioned between the barriers. In Fig. 2, since the inorganic powder of the black paste used is a metal oxide or a black coloring agent, and a glass powder is additionally contained, a small amount of metal powder is sometimes added, and the obtained black layer is poor in conductivity, so that the bus electrode 10 is provided. A conductive electrode 7 having good conductivity must be fabricated to ensure that the bus electrode can enhance the conductivity of the transparent electrode 1. After sintering is completed, the electrode 7 will form good electrical contact with the transparent electrode 1. SUMMARY OF THE INVENTION An object of the present invention is to provide a black conductive paste which has good coloring property and electrical conductivity while being used for a plasma display. Another object of the present invention is to provide a plasma display having a simplified structure. In a first aspect of the invention, there is provided a black conductive paste for a front panel of a plasma display, comprising an inorganic powder and an organic component commonly used to form an electrode of a display panel, wherein the inorganic powder is a powder of glass powder and a conductive metal Composition, the metal powder has an average particle diameter in the range of 10 to 1000 nm, and preferably not more than 800 nm, more preferably not more than 380 nm, and when the conductive metal is silver, the particle diameter of the metal powder is not lower than 14 nanometers. Wherein, the metal powder has a weight percentage of 10 to 95% based on the total weight of the inorganic powder composed of the metal powder and the glass frit. In a second aspect of the invention, a plasma display is provided, comprising a front panel and a rear panel, The bus electrode on the front panel is provided with only one layer, and the bus electrode is formed of a black conductive paste prepared from an inorganic powder and an organic carrier, wherein the inorganic powder is composed of a glass powder and an ultrafine metal powder. The ultrafine metal powder has an average particle diameter of 10 to 1000 nm, and preferably does not exceed 800 nm, more preferably does not exceed 380 nm. When the conductive metal is silver, the metal powder has a particle diameter of not more than 14 nm. In a preferred embodiment, the black strips disposed between the electrodes are also formed from the black conductive paste. The present invention produces a black conductive paste using an ultrafine powder of a good conductor metal as a colorant and a conductive material. The black layer made of the slurry has high blackness and good electrical conductivity, so it can be used to make black strips and black bus electrodes. Due to its good electrical conductivity, there is no need to make one on the black bus electrodes. A layer of white bus electrodes simplifies the process steps. BRIEF DESCRIPTION OF THE DRAWINGS Advantages and features of the present invention will become more apparent from the detailed description of the embodiments of the appended claims. 1 is a schematic structural view of a conventional plasma display; FIG. 2 is a schematic structural view of a front panel of a conventional plasma display; and FIG. 3 is a schematic structural view of a front panel of the plasma display of the present invention. DETAILED DESCRIPTION OF THE INVENTION All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art The main feature of the present invention is to utilize the color change of the metal powder due to the size effect. The present invention is based on the principle that when the substance is made into an ultrafine powder such that the size of the particles is equivalent to or smaller than the wavelength of the light wave, the light absorption is remarkably enhanced due to the small size effect. Therefore, when the metal is subdivided to a size smaller than the wavelength of the light wave, the original metallic luster will be lost and black. In the case of ^:: the smaller the size, the darker the color. However, for the metal powder used to form the electrode, the finer the particle size, the better. When the color requirement is satisfied, the necessity of conductivity must also be considered. For each metal, there is a particle size threshold. When the particle size of the metal drops to the particle size threshold, the electron energy level near the metal Fermi level changes from a continuous band to a discrete level. Will lose conductivity. For example, when the diameter of the 4 艮 particles is less than 14 nm, it will become an insulator. Therefore, to ensure the conductivity of the metal particles, the particle size of the particles cannot be less than the particle size threshold. Thus, the black conductive paste of the present invention is composed of an inorganic powder and an organic component, wherein the inorganic powder is a mixture of a glass powder and an ultrafine metal powder, wherein the ultrafine metal powder has an average particle diameter of 10 to 800 nm. Preferably, it is 10 to 380 nm, and the maximum particle diameter is not more than 1000 nm, preferably not more than 380 nm. Among them, for silver metal, the particle diameter of the metal powder should be not less than 14 nm. In addition, particles having a particle diameter of less than 10 nm tend to aggregate in the slurry, and it is difficult to have good electrical conductivity. In order to ensure blackness, the particle diameter cannot be larger than the wavelength of visible light, so the maximum particle diameter does not exceed 1000 nm, and even preferably does not exceed 380 nm. The content of the ultrafine metal powder in the slurry is 10 to 95% based on the total weight of the inorganic powder. If the weight content of the ultrafine metal powder is less than 10%, good electrical conductivity and high blackness cannot be obtained. If it exceeds 95%, the glass powder content is low, and the sinterability of the slurry is lowered. In order to ensure good conductivity of the slurry after sintering, the ultrafine metal powder in the slurry is preferably an ultrafine powder of good conductors such as gold, silver, copper, aluminum, etc. In terms of cost, the price of silver, copper, aluminum, etc. is low. A metal powder, of which silver is more preferred. When an easily oxidizable metal powder such as copper, silver or aluminum is added, it is necessary to sinter the slurry under a reducing atmosphere to prevent the metal from being oxidized to lower the conductivity of the black layer. It is generally necessary to add a glass frit to the conductive paste to ensure adhesion between the electrode material and the glass substrate after sintering. Moreover, the glass frit can make good contact of the metal particles after sintering. The glass powder is not particularly limited in the present invention. Generally, glass powders currently used in existing plasma displays can be used, for example, the currently used glass frits of PbO-B ₂ 0 ₃ -SiO ₂ . The average particle size of the glass frit is generally from 0.5 micrometers to 8 micrometers, and the content in the inorganic powder is between 5 and 90%. The above organic component, also referred to as an organic vehicle, is used to modulate the above inorganic powder material into a slurry dog for coating and bonding to a display substrate as needed. The conductive paste of the present invention can be attached to a glass substrate by screen printing or photolithography. The organic vehicle for the conductive paste for printing is composed of an inert solvent and a binder resin, and the organic carrier for the photosensitive conductive paste for lithography is composed of a solvent, a reactive diluent (monomer), a photoinitiator, and an alkali-soluble resin. Examples of the resin binder which can be used are: a cellulose resin such as ethyl cellulose, nitrocellulose or hydroxyethyl cellulose, an acrylic resin such as polybutyl acrylate or polydecyl acrylate, and those containing non-acid An organic polymer of a comonomer or an acidic comonomer, preferably a copolymer or a mixture of a non-acidic comonomer and an acidic monomer containing an ethylenically unsaturated carboxylic acid, wherein The comonomer is selected from the group consisting of d-do alkyl acrylates, d-doalkyl acrylates, styrene, substituted styrenes or combinations of these compounds. Solvents, mainly terpenes such as α ((3, γ)-terpineol, ethylene glycol pit-based (two-pile) ethers, diethylene glycol-pit-based (two-pile) ethers, B Diol-pitch-based (two-pile) ether diacetate, diethylene glycol-pit-based (two-pile) ether diacetate, propylene glycol-pit-based (two-pile) ether, propylene glycol-pit (two pit base) alcohols such as ether diacetate, dibutyl phthalate, decyl alcohol, ethanol, isopropanol, and 1-butanol, which may be used alone or in combination of two or more types. The diluent may be a reactive diluent or an inactive diluent, wherein a reactive diluent is preferred. Examples of reactive diluents that may be used include, but are not limited to, styrene, butyl acrylate, vinyl acetate, 1,6-hexane. Alcohol diacrylate, bis/tripropylene glycol diacrylate, bis/triethylene glycol diacrylate, ethoxylated bisphenol quinone diacrylate, polyethylene glycol diacrylate. The reactive diluent may be used singly or in combination. The non-reactive diluents include, but are not limited to, aliphatic alcohols. Aliphatic alcohol esters, such as acetates and propionates, pine resins, a- or beta-terpineols or mixtures thereof, terpenes: ethylene glycol and L-alcohol esters, such as ethylene glycol monobutyl ether And butyl cellosolve acetate: butyl carbitol and carbitol, such as butyl carbitol acetate and carbitol acetate: butyl 6 & 1 (2,2,4-tridecyl- 1, 3-pentanediol monoisobutyrate). As an alternative embodiment, the organic component used in the present invention contains a monomer capable of photochemical polymerization, or a homopolymer made of these monomers, After the organic component containing the monomer or the polymer is formed on the substrate, a photolithography process may be performed to form a desired pattern on the substrate. In the above embodiment, the photopolymerizable monomer may be used alone. Or used in combination with a plurality of monomers. Examples of such monomers include, but are not limited to, (fluorenyl) tert-butyl acrylate, 1,5-pentanediol di(mercapto)acrylate, bismuth (mercapto) acrylate, Ν- two Yue ^ yl ethyl ester, bis (Yue-yl) acrylate, ethylene glycol di (Yue-yl) acrylic acid I, ⁴ - D Alcohol ester, diethylene glycol bis(indenyl)acrylate, 1,6-hexanediol di(indenyl)acrylate, 1,3-propanediol di(indenyl)acrylate, di(indenyl)acrylic acid 1, 10-decyl glycol ester, 1,4-cyclohexanediol bis(indenyl)acrylate, 2,2-dihydroxydecylpropane bis(indenyl) acrylate, bis(indenyl) glycerol acrylate , bis(indenyl)tripropylene glycol acrylate, tris(decyl)acrylic acid glycerol ester, three Hydroxymercaptopropane tris(indenyl) acrylate, a compound disclosed in U.S. Patent No. 3,380,381, 2,2-bis(p-hydroxyphenyl)propane bis(indenyl)acrylate, pentaerythritol tetrakis(decyl)acrylate Ester, triethylene glycol diacrylate, bisphenol A-bis[3-(indolyl)acryloyloxy- ² -hydroxypropyl]ether, bisphenol A-bis[2-(indolyl)acryloylethyl Ether, 1,4-butanediol di-3-(mercaptoacryloyloxy-2-hydroxypropyl) ether, triethylene glycol dimercaptoacrylate, polyoxypropyl trihydroxy decyl propyl pit acrylate, (Yue-yl) acrylate, butylene glycol, tris (Yue-yl) acrylate, the I, ^2, ⁴ - butanediol di (Yue-yl) acrylate, 2, ^2, ⁴ - three-1,3 Yue - pentyl glycol ester, 1-phenylvinyl-1,2-dimercapto acrylate, diallyl fumaric acid, styrene, 1,4-phenylglycol diisopropyl acrylate, 1,4- Dipropylene benzene, 1,3,5-triisopropenyl benzene, (decyl) glycidyl acrylate, allyl glycidyl ether, (fluorenyl) α-mercapto propyl acrylate and (曱Alkyl propyl acrylate. In this paper, (fluorenyl) Acrylate means an acrylate or acrylate Yue this end, introduced into a conventional amount of the photopolymerization initiator in the organic component of the present invention may optional photoinitiators include: Yue diphenyl ketone, α _- two oxygen Yue Base- _α -phenylacetophenone, a, (X-diethoxyacetophenone, 2-hydroxy-2-indolyl-1-phenylacetone, 2-phenyl-2-diguanidino-1 - (4-morpholinylphenyl)-butanone-1, 1-hydroxy-cyclohexyl benzophenone, α-aminoalkylphenone, bisbenzoylphenylphosphine oxide, tetramethylene fluorenone, 4, 4,-Diphenoxydibenzophenone. It may be initiated by one initiator or may be initiated by two or more combinations of initiators. Preferred 2-phenyl-2-diindole-1-(4-? Porphyrin phenyl)-butanone-1, and a combination thereof containing the same agent I. The conductive paste of the present invention may contain such as a stabilizer, a plasticizer, a mold release agent, a stripping agent, and a defoaming agent. Other ingredients of the agent and wetting agent are well known to those skilled in the art. The relative amounts of the various ingredients in the above organic ingredients are readily obtained by those skilled in the art based on their own experience or by simple experimentation. In a specific embodiment of the present invention, the printed conductive paste organic carrier is composed of 4 - 8 wt% of a polymer resin binder, 92 - 96 wt% of an inert solvent, and then 50 to 70 wt% of inorganic powder, 30 to 50 wt%. The organic carrier is mixed with 1 to 3 wt% of a polyester dispersant to form a slurry. The photosensitive conductive paste is composed of 50 to 70 wt% of inorganic powder, 8 to 15 wt% of an inert solvent, and 5 to 7 wt% of a photosensitive active ingredient. 5 to 7 wt% of an alkali-soluble resin and 1 to 3 wt% of a polyester-based dispersant are stirred and mixed, wherein the photosensitive active component contains 15 to 20 wt% of a photoinitiator and 80 to 85 wt% of a reactive diluent. The step of forming a black layer on the front substrate by screen printing comprises: 1) preparing a slurry: stirring and mixing a predetermined amount of a resin binder and a solvent, heating in a water bath (oil bath) to obtain an organic vehicle; and then adding an inorganic powder, The amount of inorganic powder accounts for the total amount of conductive paste 50 ~ 70wt%, of which fine metal (average particle size of 10 ~ 800nm) accounted for 10 ~ 95% of inorganic powder. Further, a polyester dispersant having a slurry amount of 1 to 3 wt% is added, followed by stirring and mixing to obtain a slurry.

2) Grinding and degassing: The slurry is ground into a suitable electrode paste of suitable viscosity and fineness by 3⁄4 rolling, ball milling, etc., vacuum defoaming and filtering, removing bubbles and removing large particles to avoid coating. The coating on the substrate generates defects such as pores and pinholes;

3) Aligning the black conductive paste on the front substrate, the so-called alignment printing means that the required electrode pattern is already on the printing screen, and accurately aligning the screen and the glass substrate on the printing machine according to the position of the graphic position, and then printing the pulp. Material to accurately coat the black material in the desired position;

4) Drying: Usually carried out at a temperature of 100 ~ 160 °C. Depending on the temperature, the drying time is controlled for 5 ~ 30 minutes. In this process, organic small molecules such as solvents are completely removed.

5) Sintering: Preferably, it is kept in a sintering furnace at 550 to 600 ° C for 10 to 20 minutes. During this process, all the organic components in the organic composition are removed, and only the above inorganic powder component remains on the substrate. , as a black conductive bus electrode and black strip on the front panel of the plasma display. The black strip and the black electrode can be printed, dried, and sintered at the same time. The black electrode can be printed and dried first, then the black strip is printed, dried, and finally sintered together. In another embodiment of the present invention, 15 to 20 wt ° / photoinitiator is first placed in 80 ~ 85 wt% of reactive diluent, sonicated to form a photosensitive active ingredient; then 50 ~ 70 wt% of inorganic Powder, 8 - 15 wt% of inert solvent, 5 to 7 wt% of photosensitive active ingredient, 5 to 7 wt% of alkali-soluble resin, and 1 to 3 wt% of polyester dispersant are stirred and mixed; then rolled into a viscosity by a three-roll mill The bus electrode slurry of about 40 Pa.s is vacuum defoamed and filtered; the black conductive paste is printed on the entire surface of the front panel, kept in a drying oven at 90 ~ 100 °C for 5 ~ 10 minutes, and then with 365 nm ultraviolet light. 400 ~ 800mJ / cm ² energy density exposure pattern, developed with 0.4% Na ₂ C0 ₃ solution at 35 ° C; Finally, in the 550 ~ 600 ° C sintering furnace 10 - 20 can be transparent on the front panel of the plasma display A black conductive bus electrode having a thickness of about 5 μm is formed on the electrode, and a black strip having a thickness of about 5 μm is formed between the discharge electrodes. The black strip and the black electrode can be simultaneously exposed, developed, sintered, or separately exposed, simultaneously developed, and sintered, and the black strip is equal in thickness to the black electrode. Solubility, Resin, Photoinitiator, Reactive Diluent The various materials described above are selected, and each functional material may be used alone or in combination of two or more. Example 1 First, ethyl cellulose, butyl carbitol acetate, and terpineol were stirred and mixed in a weight ratio of 5:13:82, and heated to 70 ° C in a water bath to obtain an organic vehicle; PbO-B ₂ 0 ₃ -SiO ₂ -based glass powder having a particle diameter of 2.5 μm and silver powder having an average particle diameter of 30 nm were mixed at a weight ratio of 9:1 to obtain an inorganic powder, wherein the glass powder contained 65 wt% of PbO. 30% by weight of Si0 ₂ , 4wt ⁰ /. B ₂ 0 ₃ and lwt ⁰ /. MgO. Then, force was applied to 100 g of the above organic vehicle. 150 g of inorganic powder and 5 g of polyester dispersant BYK111 (purchased from BYK Chemical Co., Ltd.), followed by planetary stirring and mixing, and rolling into a bus electrode slurry having a viscosity of about 40 Pa's by a three-roll mill, vacuum defoaming And filtering; on the front substrate (as shown in Figure 3), the black conductive paste is printed in the opposite position, and the organic solvent is removed in a drying oven at 150 ° C for 15 minutes. After drying, the thickness is controlled to be about 104 meters. Finally, at 570 ° C. In the sintering furnace for 20 minutes, a black conductive bus electrode 10 having a thickness of about 5 μm is formed on the front panel transparent electrode 1 of the plasma display panel, and a black strip having a thickness of about 5 μm is formed between the pair of discharge electrodes. 9. The black strip 9 and the black electrode 10 can be simultaneously printed, dried and sintered at the same time. At this time, the thickness of the black strip 9 is 5 4, and the electrode 10 can be printed and dried first, then the black strip 9 is printed and dried, and finally sintered. , to ensure that the thickness of the black strip 9 is not less than 1 ^ Kaimi. Example 2 18 g of α-dimethoxy-α-phenylacetophenone was placed in 82 g of butyl acrylate, and ultrasonically dissolved to prepare a photosensitive active ingredient; by passing a glass powder having a median diameter of 3.0 μm. And silver powder having an average particle diameter of 300 nm is mixed in a weight ratio of 5:95 to obtain an inorganic powder, wherein the glass powder contains 65 wt% of PbO, 30 wt% of SiO ₂ , 4 wt% of B ₂ O ₃ and 1 wt% MgO. Then, 70 g of the above inorganic powder, 15 g of terpineol, 7 g of the photosensitive active ingredient, 6 g of polydecyl methacrylate-yl decyl acrylate and 2 g of BYK 111 planetary stirring were mixed and rolled to a viscosity of 40 Pa by three rolls. Between the left and right bus electrode slurry, then vacuum defoaming and filtering; printing black conductive paste on the front surface of the entire surface, kept in a drying oven at 100 ° C for 10 minutes, after drying, the thickness is about 1 (H Kaimi, then use The 365 nm ultraviolet light is exposed at a density of 600 mJ/cm ² , developed with a 0.4% Na ₂ CO ₃ solution at 35 ° C; and finally held in a 560 ° C sintering furnace for 15 minutes and 4 t, which can be in front of the plasma display. A black conductive bus electrode 10 having a thickness of about 5 meters is formed on the transparent electrode of the panel 1 , and a black strip 9 having a thickness of about 5 μm is formed between the pair of discharge electrodes. The black strip 9 and the black electrode 10 can be simultaneously exposed, developed, and sintered. Also with electrodes

10 is separately exposed, simultaneously developed, and sintered, and the thickness of the black strip 9 is equal to that of the electrode 10. The following is a comparison of the products made by the industry's mature electrode paste according to the conventional process. Comparative Example 1 On the transparent electrode 1, the NP4734 black bus electrode slurry of Noritake Co., Ltd. was used for the offset printing to obtain the bus electrode 10 and the black strip 9, and dried at 120 ° C for 10 minutes, and the thickness of the dried layer was 4 μm. Then, the Noritake company was used. NP4735 white bus electrode paste is printed in position, white bus electrode 7 is formed on 10, dried at 120 ° C for 10 minutes, and the thickness of the dried layer is 8 μm. Finally, the black and white electrode pastes are kept together in a sintering furnace at 570 °C. In minutes, the total thickness of the sintered bus electrode is 6 microns, and the thickness of the black bar 9 is 2 £ meters. Comparative Example 2 On the transparent electrode 1, the DC243 black bus electrode paste of Dupont Co., Ltd. was printed on the front substrate, dried at 80 ° C for 20 minutes, dried at a thickness of 4 μm, and irradiated with 365 nm of ultraviolet light at 600 mJ/cm ^{2 .} Density exposure black bus electrode and black strip pattern template; then use Dupont DC206 white bus electrode paste printed on the black layer, 80 ° C drying for 20 minutes, dry layer thickness 8 microns, with 365 nm UV light The white bus electrode pattern template was exposed at an energy density of 600 mJ/cm ² , developed with a 0.4% Na ₂ CO ₃ solution at 35 ° C, and then held in a 560 ° C sintering furnace for 15 minutes, and the total thickness of the bus electrode after sintering was 6 μm. The black strip 9 has a thickness of 2 microns. Table 1 lists the performance test results of the products obtained in Examples 1 and 2 and Comparative Examples 1 and 2. Table 1 Performance test results of each sample

The sample thickness of the sheet resistance is 10 μm; the interface reflectance of the glass substrate and the black layer measured on the front glass substrate side is an L value of brightness, and the value is preferably 15 or less, more preferably 10 or less. The smaller the L value, the more the material layer is. * The reflectance of visible light at the same sample layer thickness is measured by an ultraviolet-visible spectrophotometer.

The value at 560 nm is compared. The lower the reflectance, the higher the contrast of the panel made with the material layer. It can be seen from the performance comparison that the blackness of the single-layer bus electrode and the black strip made of the black conductive paste of the present invention is superior to that of the conventional two-layer bus electrode and the black strip as viewed from the front glass substrate side. Moreover, the conductivity of the electrode is not lowered, so that the panel significantly improves the display contrast while simplifying the manufacturing process. Comparing Fig. 2 with Fig. 3, it can be seen that, unlike the prior art, in the present invention, the ultrafine metal powder in the material allows the obtained black layer to have both high blackness and good electrical conductivity, so that the black bus electrode 10 is It is no longer necessary to form the electrode 7 of high conductivity, which simplifies the process steps. Further, the black strip 9 can be produced using the black paste of the present invention.

Claims

Claim

A black conductive paste for a front panel of a plasma display, comprising an inorganic powder and an organic component commonly used to form an electrode of a display panel, wherein the inorganic powder is composed of a powder of glass powder and a conductive metal, characterized in that The average particle diameter of the metal powder is in the range of 10 to 1000 nm, and when the conductive metal is silver, the particle diameter of the metal powder is not less than 14 nm.

The black conductive paste according to claim 1, wherein the metal powder has an average particle diameter of not more than 800 nm.

The black conductive paste according to claim 2, wherein the metal powder has an average particle diameter of not more than 380 nm.

The black conductive paste according to any one of claims 1 to 3, wherein the metal powder is gold, silver, copper and aluminum powder.

The black conductive paste according to claim 4, wherein the metal powder has a weight percentage of 10 - 95% based on the total weight of the inorganic powder composed of the metal powder and the glass frit.

6. A plasma display comprising a front panel and a rear panel, wherein: the bus electrode on the front panel is provided with only one layer, and the bus electrode is formed of a black conductive paste prepared from inorganic powder and organic components. Wherein the inorganic powder is composed of a glass powder and an ultrafine metal powder, the ultrafine metal powder has an average particle diameter of 10 to 1000 nm, and when the conductive metal is silver, the particle diameter of the metal powder is not Below 14 nm.

The plasma display according to claim 6, wherein the metal powder has an average particle diameter of not more than 800 nm.

The plasma display according to claim 7, wherein the metal powder has an average particle diameter of not more than 380 nm.

9. The plasma display according to claim 6, wherein the black stripes disposed between the electrodes are also formed of the black conductive paste.

The plasma display according to claim 6, wherein the metal powder has a weight percentage of 10 to 95% based on the total weight of the inorganic powder.