KR100757519B1 - Fabrication Method of Electrode for Plasma Display Panel Using Precoating Solution - Google Patents

Abstract

The present invention relates to a method of manufacturing an electrode for a plasma display panel (PDP) by an inkjet method, and more particularly, to form an electrode pattern by a conventional inkjet method, but the binder polymer and glass frit After forming a pre-treatment coating film by applying a pre-treatment coating solution comprising a silver nano-powder and a binder polymer on the coating film, the electrode pattern is formed by applying a silver ink composition for forming the electrode does not contain glass frit, thereby forming an electrode pattern It is possible to prevent the clogging of inkjet nozzle holes due to the sedimentation of the glass frit contained in the silver ink composition, and to prevent the bleeding of the silver ink sprayed by the glass frit contained in the pretreatment coating liquid. Plasma by inkjet method which enabled formation A method for manufacturing an electrode for a display panel.

Plasma display panel, pretreatment coating liquid, electrode, inkjet method

Description

Fabrication Method of Electrode for Plasma Display Panel by Inkjet Method {Fabrication Method of Electrode for Plasma Display Panel Using Precoating Solution}             

1 is a schematic view showing a cross section of a conventional surface discharge type AC PDP.

2A to 2C are electrode forming process diagrams using the photosensitive electrode paste according to the prior art.

3 is a flow chart for preparing a pretreatment coating solution of the present invention.

Figure 4 is a schematic diagram of forming an electrode pattern using a piezoelectric (Piezo) type inkjet equipment on the pre-treatment coating film of the present invention.

5 is a POM photograph of an electrode pattern using a pretreatment coating solution of Comparative Example 1.

6 is a POM photograph of an electrode pattern using a pretreatment coating solution of Example 2 of the present invention.

7 is a POM photograph of an electrode pattern using a pretreatment coating solution of Comparative Example 2.

8 is a POM photograph of an electrode pattern using the pretreatment coating solution of Example 3 of the present invention.

[Description of Major Symbols in Drawing]

   10: back substrate 11: address electrode 12: white dielectric 13: partition wall

   14: front substrate 15: transparent electrode 16: bus electrode

   17 transparent dielectric film 18 dielectric protective film 19 phosphor

   31: inkjet equipment 32: electrode pattern 33: pretreatment coating film 34: substrate

The present invention relates to a method of manufacturing an electrode for a plasma display panel (PDP) by an inkjet method, and more particularly, to form an electrode pattern by a conventional inkjet method, but the binder polymer and glass frit After forming a pre-treatment coating film by applying a pre-treatment coating solution comprising a silver nano-powder and a binder polymer on the coating film, the electrode pattern is formed by applying a silver ink composition for forming the electrode does not contain glass frit, thereby forming an electrode pattern It is possible to prevent the clogging of inkjet nozzle holes due to the sedimentation of the glass frit contained in the silver ink composition, and to prevent the bleeding of the silver ink sprayed by the glass frit contained in the pretreatment coating liquid. Plasma by inkjet method which enabled formation A method for manufacturing an electrode for a display panel.

In PDP, vacuum ultraviolet rays (wavelength about 147 nm) emitted from the plasma generated when the inert gas is discharged impinge on the fluorescent film, thereby causing red (R, R), green (G) and blue (Blue, B) in the visible region. As a flat panel display device using the phenomenon of changing to light, full color display, fast response speed, wide viewing angle, and easy to implement a large display device of 40 inches or more are the next generation display such as high-definition television (HDTV). Is attracting attention as one of.

The PDP is divided into a direct current (DC) type and an alternating current (AC) type, and the AC type is further divided into a counter discharge type and a surface discharge type according to the electrode structure of the discharge cell. The opposite discharge type has a problem in that the lifetime is shortened due to deterioration of the phosphor due to the ion bombardment. On the other hand, the surface discharge type overcomes the problems of the opposite discharge type structure by collecting discharges on opposite sides of the phosphor to minimize phosphor degradation, and most PDPs adopt this method.

1 is a cross-sectional view of a surface discharge type plasma display panel (AC PDP). Referring to FIG. 1, in the surface discharge type AC PDP, a rear substrate 10, an addresser electrode 11, a white dielectric 12, a partition 13, and the like constitute a rear substrate, and the front substrate 14 and the transparent electrode ( 15, the bus electrode 16, the transparent dielectric film 17, the dielectric protective film 18, black stripe (not shown), etc. form a front plate. Phosphors (R, G, B) 19 for realizing color in the PDP are disposed on the front plate in the case of a transmissive type and between partition walls 13 of the back plate as shown in the case of a reflective type.

The metal electrode of the AC PDP includes an address electrode 11 formed on the rear substrate 10 and a bus electrode 16 formed on the transparent electrode 15 of the front substrate 14. Conventionally, such an address electrode was formed by photolithography using silver paste.

2A to 2C are electrode forming process diagrams using the photosensitive electrode paste according to the prior art. Referring to FIGS. 2A to 2C, first, the photosensitive electrode paste is applied using a screen printer, and then a photomask is disposed to be exposed to ultraviolet rays (UV). At this time, the portion of the UV exposure is not developed by the aqueous alkali solution by light crosslinking, while the portion that is not UV exposure is developed by the aqueous alkali solution, so that the electrode pattern is formed as shown in Figure 2c. However, the electrode formation using the above-mentioned photosensitive electrode paste has disadvantages in that the control of the precision of the pitch and the control of the electrode width is disadvantageous and the loss of material is large.

In the case of the bus electrode of the front substrate, indium tin oxide (ITO), which is used as a transparent electrode of the PDP, has a high sheet resistance and thus forms an opaque bus electrode having high conductivity. Since the bus electrode cuts off the emitted light generated from the fluorescent surface and lowers the luminance, it is necessary to make the bus electrode as thin as possible in the range where the required line resistance is obtained.

The PDP bus electrode is mainly formed by a vacuum deposition / etching process with a three-layer structure of chromium / copper / chrome. However, the method of forming a three-layer bus electrode of chromium / copper / chromium by vacuum deposition has a long process time, a high price of a thin film forming apparatus and a material, and environmental pollution during etching. Due to this problem, a method of forming a fine pattern by photolithography using a photosensitive silver paste has been recently applied in the same way as the formation of a bus electrode.

However, in PDPs having a larger screen size than other displays, precise alignment between the substrate and the photomask is required, and the position of the electrode pattern does not stay in place due to a very small alignment error. have. As described above, the formation of the electrode pattern by the photolithography method is a situation in which the control of the precision of the pitch and the width of the fine electrode is disadvantageous, and the loss of material is large.

Therefore, in the plasma display panel, the formation of the address electrode and the bus electrode is required in a piezo type inkjet method capable of fine line width, low material loss, and simple process.

In order to form electrodes using piezoelectric inkjet equipment, manufacturing of the electrode ink is first required, and the components of the electrode ink are generally nano-sized silver powder, glass frit, solvent and binder. Polymer is the basic composition. If necessary, a small amount of various additives such as dispersants and thickeners may be added to ensure dispersibility and sedimentation stability of the silver powder and glass frit, which are inorganic components.

The ink is ejected through the inkjet apparatus to form a predetermined shape pattern, and the organic material is calcined and removed by heat treatment at a high temperature to complete the formation of the final electrode pattern. At this time, the glass frit is firmly bound to the lower plate or the upper plate glass of the PDP by fusion of the thin fine line width silver film formed as an electrode while being thermally fused to prevent the thin and fine line electrode pattern from being lost by external impact or contact. It serves to prevent.

The silver (Ag) ink for PDP composed of the above-mentioned silver powder, glass frit, solvent, binder polymer and additives is sprayed through a fine nozzle of the inkjet apparatus, and forms a pattern of a predetermined shape. However, the sedimentation of the glass frit with a large specific gravity and a large particle diameter occurs with a long time of use, thereby causing a problem of clogging the holes of the inkjet nozzle.

In addition, the water-based silver (Ag) ink sprayed onto the substrate does not adhere to the substrate glass and smears on the upper and lower glass substrates of the PDP due to the interfacial tension, making it difficult to form a microelectrode pattern for PDP and control pattern precision. There is a problem.

Accordingly, the inventors of the present invention have made efforts to solve the above problems, and as a result, by applying a pretreatment coating solution containing a binder polymer and a glass frit to form a pretreatment coating film, it contains silver nano powder and a binder molecule, glass frit When the electrode pattern is formed by applying the excluded silver ink composition, it was found that nozzle clogging does not occur when the existing silver ink is used, and the spreading of the ejected silver ink can be controlled to complete the present invention.

Accordingly, an object of the present invention is to provide a method for manufacturing an electrode for a plasma display panel by an inkjet method capable of forming an electrode for a plasma display panel with high precision and high resolution.

The present invention provides a method of manufacturing a plasma display panel electrode by an inkjet method, comprising: applying a pretreatment coating solution including a binder polymer, a solvent, and a glass frit to a substrate and heat-treating the same to form a pretreatment coating film; A method of manufacturing an electrode for a plasma display panel comprising applying a silver ink composition for forming an electrode including silver nanopowder, a binder polymer, and purified water on a pretreatment coating film and then firing to form an electrode pattern.

Hereinafter, the present invention will be described in detail.

The present invention forms an electrode for a PDP by an inkjet method, and in particular, in forming a PDP electrode by a piezo method, a pretreatment coating liquid including a binder polymer and glass frit is coated to form a pretreatment coating film. Thereafter, the silver film is formed on the top of the coating layer, and the electrode pattern is formed by applying a silver ink composition for forming an electrode that does not contain glass frit to form an electrode pattern, so that the glass frit settles in the existing silver ink composition. High-precision and high-resolution plasma display panel can be prevented from clogging the inkjet nozzle by the ink and the silver ink sprayed by the glass frit contained in the pretreatment coating liquid is fixed to the pretreatment coating film to effectively control the bleeding of the silver ink. Plasma Display by Ink Jet Method Ray relates to a method for producing an electrode for electric panel.

Hereinafter, the manufacturing method of the electrode for PDP of this invention is demonstrated in detail for each step based on an accompanying drawing.

First, a pretreatment coating solution including a binder polymer, a solvent, and a glass frit is applied to a substrate and heat-treated to form a pretreatment coating film.

The pretreatment coating liquid composition includes 5 to 25% by weight of binder polymer, 50 to 80% by weight of solvent and 0.5 to 20% by weight of glass frit, and optionally acrylic or amine dispersant, silicone antifoaming agent, thickening agent. 0.5 to 5% by weight of an additive or a mixture of two or more selected from the agent, pressure-sensitive adhesive and leveling agent may be further included.

The pretreatment coating solution of the present invention can be prepared by the following method.

First, the binder polymer is added to a solvent to have an appropriate viscosity (5,000 to 10,000 cps), and dissolved by heating for 1 to 24 hours within a temperature range of 30 to 80 ° C. Then, the solvent and the glass frit are added to 0.4 in a separate container. After adding zirconia beads of ˜0.6 mm, a mixed solution prepared by uniformly dispersing for 1 to 24 hours in a beads mill is added. The mixed solution is uniformly mixed and dispersed. At this time, it is preferable to use a ceramic 3 roll mill.

A small amount of additives may be used in combination with the glass frit and the solvent in order to secure the dispersion and sedimentation stability of the glass frit in the mixed solution, to secure the viscosity characteristic of the pretreatment coating solution, to remove bubbles, and to stabilize the flow and porosity characteristics. The above process is shown schematically in FIG. 3.

A method of forming a pretreatment coating film using the pretreatment coating solution will be described with reference to FIG. 4. The pretreatment coating solution is applied onto the glass substrate 34 of the PDP to be used first by a printing method or a spin coating method. Then, the mixture is heated and dried for 5 to 30 minutes within a temperature range of 50 to 130 ° C. At this time, the thickness after drying of the pretreatment coating film 33 is suitably 0.1-5 micrometers.

As the binder polymer, polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, polymethacrylic acid, polyethylene oxide, polyvinyl alcohol, gelatin, polysaccharide and cellulose derivative may be used, and specifically, the cellulose derivative may be used. Ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethyl hydroxypropyl cellulose and the like can be used.

The solvents include cyclohexanone, cyclohexane, ethylene glycol, 2-butoxy ethoxy ethanol, 2-ethoxy ethanol, 3-methoxy-3-methyl butanol One or more organic solvent mixtures selected from (3-methoxy-3-methyl butanol), propylene glycol methyl ether, terpineol, dimethylformamide, dimethylacetamide and the like can be used.

The glass frit is a component that bonds and bonds the silver electrode pattern formed by the inkjet method onto the substrate of the PDP after firing, and is commonly used in the art, such as lead oxide, bismuth oxide, zinc oxide, and lithium oxide glass frits. You can use the glass frit used by. When introducing the composition of lead oxide glass frit, PbO is 40 to 80%, B ₂ O ₃ is 1 to 20%, SiO ₂ is 3 to 20%, Al ₂ O ₃ is 0 to 10%, BaO is 0 to 10%, It is known that ZnO has a composition of 0 to 15%, TiO ₂ to 0 to 2%, and Bi ₂ O ₃ to 0 to 10%.

As the additive, various additives such as acrylic and amine-based dispersants, silicone-based antifoaming agents, thickeners, pressure-sensitive adhesives, and smoothing agents may be used to control the flow characteristics and storage stability of the pretreatment coating solution according to the present invention. It can be understood that it is known to those skilled in the art to be commercially available for use.

Secondly, a silver ink composition for forming an electrode including silver nanopowder, a binder polymer, and purified water is coated on the pretreatment coating film and then baked to form an electrode pattern.

The silver ink composition for forming an electrode includes 10 to 50% by weight of silver nanopowder, 0.1 to 10% by weight of a binder polymer, and 20 to 50% by weight of purified water, and if necessary, 30 to 60 additives used in the pretreatment coating solution. The weight percent may further include.

The silver nano powder is preferably used in the size range of 10 to 500 nm, the binder polymer may be selected from the same type used in the pretreatment coating solution.

When the formation of the pretreatment coating film is completed, the electrode forming silver (Ag) ink is discharged from the inkjet device 31 to form an electrode pattern 32 having a predetermined shape. The substrate on which the electrode pattern is formed is thermally decomposed to remove organic components such as binder polymer and other additives included in the electrode pattern through a process of firing (450 to 600 ° C.), thereby obtaining an electrode pattern composed of only a metal electrode (silver) and glass frit. .

The water-based silver (Ag) ink composition for forming an inkjet PDP electrode according to the present invention comprises nano-sized silver particles, a binder polymer and purified water, and various additives as necessary, and is used in a conventional inkjet method. Unlike the glass frit.

The reason for not including the glass frit in the silver ink composition of the present invention is that the glass frit already exists in the pretreatment coating liquid.

That is, by spraying water-based silver ink on the dried pretreatment coating film to form an electrode pattern of PDP and firing, the glass frit present in the pretreatment coating film is fused onto the PDP substrate glass and the silver powder component of the inkjet silver ink thereon This is because they are fused in this firing step to form a silver electrode film with a thin film. In this case, the thin film formed by fusion of the glass frit of the lower layer on the PDP glass substrate forms protrusions of many fine sizes, and thus the PDP fused thereon serves to greatly increase the adhesion of the electrode thin film pattern.

In this way, the glass frit that maintains the pattern shape of the silver electrode is included in the pretreatment coating liquid instead of being included in the silver (Ag) ink composition which is sprayed by the inkjet method, and then sprayed by the silver particles in the silver ink (about 10 to 500 nm). Unlike), it is possible to prevent the clogging of the nozzle of the inkjet equipment by the sedimentation of the glass frit of the micron size, and also includes a water-soluble polymer binder that acts as an absorbing layer of water, which is a solvent component of the water-based silver (Ag) ink composition. By forming the prepared pretreatment coating film on the surface of the substrate in advance, it is possible to prevent the bleeding of the discharged silver ink, thereby forming an electrode having excellent pattern accuracy.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the following Examples.

Examples 1-2 and Comparative Example 1

Next, a pretreatment coating solution was prepared using the composition shown in Table 1, which was applied (screen printing) and dried (110 ° C., 10 minutes) to form a pretreatment coating film.

The ink pattern silver (Ag) ink composition for forming a PDP electrode was sprayed on the pretreatment coating film to form an electrode pattern, and the shape thereof was examined. At this time, the silver (Ag) ink composition discharged on the pre-treatment coating film is 4.8g of amine-based binder polymer (polyallylamine), 6g of amine-based dispersant (Byk-163, manufactured by Byk), 12g of Ag powder (average of 10-500nm) and solvent Consisting of 17.2g of primary distilled water, and after mixing each component was milled for 3 hours using a milling equipment was prepared by finely dispersing the silver powder.

division Ingredient (unit: g) Example 1 Example 2 Comparative Example 1 Polymer binder ¹⁾ 1.756 1.756 - Dispersant ²⁾ - 0.08 0.08 Glass frit ³⁾ 0.22 0.22 0.22 Organic solvents ⁴⁾ 5.26 5.26 5.26 Sum 7.236 7.316 5.56 1) hydroxyethyl cellulose 2) Byk-163, manufactured by Byk. 3) Lead oxide glass frit, trade name YCO-7 4) Propylene glycol ethyl ether

When the silver ink composition is coated after forming the pretreatment coating film using the pretreatment coating liquid composition which does not add the cellulose-based binder polymer shown in Comparative Example 1 of Table 1, the formation of the pretreatment coating film is almost impossible due to the addition of the binder polymer. It was impossible, and the ink bleeding occurred in the process of spraying the silver ink composition for the electrode. 5 is a SEM photograph of an electrode pattern in which silver (Ag) ink is sprayed on the pretreatment coating film formed by using the pretreatment coating solution of Comparative Example 1 by using an inkjet device. Referring to FIG. 5, the electrode pattern on the pretreatment coating film not including the cellulose-based binder polymer was not uniform, and the line width was thick even though the same amount of ink was discharged.

In the case of using the pretreatment coating liquid composition without adding the dispersant of Example 1, the coagulation phenomenon of the glass frit powder occurred during the electrode paste manufacturing process due to the addition of the dispersant, but the surface of the pretreatment coating film was rough. There was no bleeding or clogging of the inkjet equipment nozzles upon spraying the composition.

In the case of forming a pretreatment coating film using a pretreatment coating solution prepared by using the dispersant, the binder polymer, the glass frit, the solvent, and the like in a predetermined composition, the silver ink composition is sprayed. Smearing of the silver (Ag) ink could be prevented, the surface of the pretreatment coating film was confirmed to be uniform, and the nozzle hole clogging phenomenon of the inkjet equipment did not appear. FIG. 6 is a SEM photograph of an electrode pattern in which silver (Ag) ink is sprayed on the pretreatment coating film formed using the pretreatment coating solution of Example 2 by using an inkjet device. Referring to FIG. 6, it can be seen that an electrode pattern having good uniformity and line width is formed.

Examples 3-4 and Comparative Example 2

In this example, the characteristics of the glass frit added and the content of the pretreatment coating solution were investigated. Next, the entire surface of the pretreatment coating solution composed of the composition shown in Table 2 was applied and dried (100 ° C., 10 minutes), and then piezoelectric inkjet equipment and the ones used in Examples 1 to 2 and Comparative Example 1 were formed thereon. The same aqueous silver (Ag) ink composition was sprayed and fired (530 DEG C, 30 minutes) to form an electrode pattern.

division Ingredient (unit: g) Example 3 Example 4 Comparative Example 2 Polymer binder ¹⁾ 1.756 1.756 1.756 Dispersant ²⁾ 0.08 0.08 0.08 Glass frit ³⁾ 0.22 0.52 - Organic solvents ⁴⁾ 5.26 5.26 5.26 Sum 7.316 7.616 7.096 1) hydroxyethyl cellulose 2) Byk-163, manufactured by Byk. 3) Lead oxide glass frit, trade name YCO-7 4) Propylene glycol methyl ether

Figure 7 shows the electrode surface photograph formed by spraying on the pretreatment coating film formed using the composition of Comparative Example 2 of Table 2. According to FIG. 7, the sharpness and uniformity of the electrode pattern was observed before firing of the electrode, but after the firing, glass frit binding the thin film Ag electrode film having a fine line width was observed. Since frit) was not added, the electrode pattern failed to maintain its shape after firing.

8 shows an electrode surface photograph formed by spraying the silver ink composition on the pretreatment coating film coated with the composition of Example 3. FIG. According to FIG. 8, it can be confirmed that due to the addition of the glass frit in the pretreatment coating liquid, a good electrode pattern having a constant line width can be obtained even after firing without loss of the electrode pattern.

When the pretreatment coating liquid composition of Example 4 was used, electrode pattern formation characteristics similar to those of Example 3 were also shown.

 As described above, according to the present invention, the pretreatment coating film is first formed with a pretreatment coating liquid containing glass frit, and then, by spraying the silver ink composition containing no glass frit by an inkjet method, the silver ink composition containing conventional glass frit. PDP manufacturing yield improvement effect can be obtained because the nozzle hole clogging phenomenon of the inkjet equipment caused by sedimentation of the glass frit in the water-based silver (Ag) ink composition, which is generated when the bay is sprayed by the inkjet method, can be prevented. .

In addition, by forming the pretreatment coating film by containing the glass frit in the pretreatment coating solution in advance, by spraying the silver ink composition, it is possible to prevent the bleeding phenomenon of the sprayed silver ink on the PDP glass substrate, thereby making it possible to form a high precision and high resolution PDP electrode. .

Although the present invention has been described in detail only with respect to specific examples, it will be apparent to those skilled in the art that various modifications and variations are possible within the spirit of the present invention, and such modifications and variations belong to the appended claims.

Claims (6)

In the method of manufacturing a plasma display panel electrode by an inkjet method, Applying a pretreatment coating solution including a binder polymer, a solvent, and a glass frit to the substrate, and heat treating the pretreatment coating film to form a pretreatment coating film; Forming an electrode pattern by applying a silver ink composition for forming an electrode including silver nanopowder, a binder polymer, and purified water on the pretreatment coating film and then baking Electrode manufacturing method for a plasma display panel comprising a. The method of claim 1, wherein the pretreatment coating solution comprises 5 to 25 wt% of a binder polymer, 55 to 80 wt% of a solvent, and 0.5 to 20 wt% of glass frit. . The plasma display of claim 2, wherein the pretreatment coating solution further comprises 0.5 to 5 wt% of one or two or more mixtures selected from acrylic or amine dispersants, silicone antifoaming agents, thickeners, pressure-sensitive adhesives and leveling agents. Method for producing electrode for panel. delete The silver ink composition of claim 1, wherein the silver ink composition for forming an electrode comprises 10 to 49.9 wt% of silver nanopowder, 0.1 to 10 wt% of a binder polymer, 20 to 50 wt% of purified water, and an acrylic or amine dispersant, a silicone antifoaming agent, a thickener, 30 to 60% by weight of one or two or more additives selected from pressure-sensitive adhesives and leveling agents. The method of claim 1, wherein the binder polymer is selected from polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, polymethacrylic acid, polyethylene oxide, polyvinyl alcohol, gelatin, polysaccharides and cellulose derivatives. An electrode manufacturing method for a plasma display panel.

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