KR100390345B1 - Electrode paste for rear panel of plasma display panel - Google Patents

Abstract

Disclosed is an electrode paste for a plasma display panel back plate having improved printing and firing characteristics. The electrode paste for the back panel of the plasma display panel can be applied to a high-quality plasma display panel of V-A (640 × 480) or more because uniform micro shape molding is possible. In addition, since the printing thickness per circuit is high, the number of repetitive prints for lowering the line resistance is about half of the conventional printing electrodes for the back panel of the plasma display panel, thereby reducing the process time and equipment investment of the printing electrodes. In addition, since the firing temperature is low and the back plate glass warping does not occur at the time of firing, it is also applicable to yield increase and general soda lime glass.

Description

Electrode paste for plasma display panel backplane {ELECTRODE PASTE FOR REAR PANEL OF PLASMA DISPLAY PANEL}

The present invention relates to an electrode paste for a plasma display panel back plate having improved printing and firing characteristics.

Plasma display panels are capable of high-speed image display and can be easily enlarged compared to liquid crystal panels. As a result, applications in high-quality TV fields as well as office automation (OA) devices and promotional display devices are expected. As such applications expand, there is a need for a plasma display panel having a low cost, high definition, and a large number of display cells.

In general, a plasma display panel displays a screen by forming a discharge space between a front glass substrate and a rear glass substrate to generate plasma discharge between electrodes to excite phosphors present around the light to emit light. Here, in order to induce plasma discharge, an address electrode and a dielectric layer are formed on the rear plate, and a partition wall is formed or a partition layer is formed on the upper side where the address electrode and the dielectric layer are formed, and then the partition wall is processed. Phosphor layer is formed so that red (R), green (G), and blue (B) colors are repeated.

In the conventional method of forming a printed electrode for a back plate of a plasma display panel, as shown in FIGS. 1 and 2, a screen mask is formed in which a portion of the sieve 13 except for a desired shape portion is covered with an emulsion 12. Is placed on the rear glass substrate of the plasma display panel, and then the electrode paste for the rear panel of the plasma display panel is applied thereon, and the opening part 11 is pushed evenly with a long flat plastic rod called a skid. The electrode is printed on the glass substrate for plasma display back panel by passing the paste through (see FIG. 2), and the electrode paste printed as described above is dried at 100 to 200 ° C. for 10 to 20 minutes, at a temperature of 560 to 580 ° C. It consists of baking for 10 to 60 minutes.

The electrode for the back plate of the plasma display panel formed by the above method is capable of forming a fine shape, so that a high quality plasma display panel can be realized, the electric line resistance must be low, and the price must be low to obtain a low driving voltage.

However, the conventional plasma display panel electrode has an increase in the firing spread ratio (the average value of the maximum widths 15 of the fired electrode after printing the electrode for the screen mask electrode pattern width value on the glass substrate for the back plate). Ratio, hereinafter referred to as a plastic spreading ratio), and a plastic electrode shape is a heterogeneous shape with severe irregularities as shown in FIG. Formation of electrodes for high quality plasma display backplanes is difficult.

In addition, the cross-sectional area is narrow as the height of the electrode formed during one printing is low, and in order to obtain a low electric line resistance of the desired plasma display panel back panel electrode, several printing-drying processes have to be repeated. Increased equipment investment costs

In addition, the existing electrode pastes are capable of firing at a temperature of 550 ° C. or higher, and thus have low yields due to warpage or the like in the rear glass substrate of the plasma display panel during the electrode firing process.

The present invention has been made to solve the above disadvantages, an object of the present invention is to provide an electrode paste for a plasma display panel back plate that can improve the printing and plasticity characteristics.

1 is an enlarged view of a general screen mask pattern portion.

Figure 2 is a view showing the shape of the electrode formed by a general printing method.

* Description of the symbols for the main parts of the drawings *

11: Opening part (= pattern width) 12: Emulsion part

13: Screen mask Sieve 14: Incomplete opening (Opening)

15: electrode maximum width 16: electrode minimum width

17: backplane electrode

In the electrode paste for plasma display panel backplane according to the present invention for achieving the above object is baked at 550 ℃ or less electrode paste for plasma display panel backplate manufactured in the electrode, the entire paste of the electrode is 49 ~ 85 silver powder wt%, glass powder 1 to 10 wt%, organic material comprises a weight fraction of 9 to 50 wt%, the silver powder has an average particle diameter of 0.5 ~ 17㎛, its shape is spherical, needle ( Iii), at least one of plate-like and amorphous, wherein the glass powder has an average particle diameter of 0.5 to 17 µm, and its composition is 43 to 91 wt% of PbO and SiO. ₂ 0-21 wt%, B ₂ O ₃ + Bi ₂ O ₃ 0-25 wt%, Al ₂ O ₃ 0-7 wt%, ZnO 0-20 wt%, Na ₂ O + K ₂ O + Li ₂ O 0-15 wt%, BaO + CaO + MgO + SrO 0-15 wt%, glass softening temperature is 320 ° C. to 520 ° C., thermal expansion coefficient is 62 to 110 × 10 ⁻⁷ / ° C., and the organic material is a binder 2 to 7 wt%, solvent 4 to 35 wt%, plasticizer 3 to 15 wt%, thixotropic agent + dispersant + leveling agent 0 to 2.5 wt%.

Hereinafter, an electrode paste for a plasma display panel back plate according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The electrode paste for the back panel of the plasma display panel according to the present embodiment is 49 to 85 wt% of silver powder as a main component of electrical conduction among all pastes, and a glass powder 1 to 10 that promotes sintering and improves the interfacial adhesion between the back glass substrate and the electrode. wt%, 9 to 50 wt% of organic material supporting these powders.

In the electrode paste, silver powder accounts for 49 to 85 wt% of the total paste, and its shape is in spherical shape, needle shape, plate shape and amorphous phase. It consists of at least one shape selected, and the average particle diameter is 0.5-17 micrometers.

If the average particle diameter of the silver powder is 0.5 µm or less, it is difficult to form a paste, and if the average particle diameter is 17 µm or more, it is difficult to densify sufficiently during firing and pores are easily generated, resulting in high electrical resistivity. When the content of the silver powder is 49 wt% or less, the thickness of the electrode formed per print decreases, so that the line resistance of the electrode for the plasma display back panel is increased, and when the content of the silver powder is 85 wt% or more, the viscosity of the electrode Is too high and printing becomes difficult.

In the electrode paste for the back panel of the plasma display panel, the glass powder accounts for 1 to 10 wt% of the total paste, and the composition is PbO 43 to 91 wt%, SiO ₂ 0 to 21 wt%, B ₂ O ₃ 0 to 26 wt%, Bi ₂ O ₃ 0 to 25 wt%, Al ₂ O ₃ 0 to 7 wt%, ZnO 0 to 20 wt%, Na ₂ O + K ₂ O + Li ₂ O 0 to 15 wt%, BaO + CaO + MgO + SrO is 0-15 wt%, glass softening temperature is 320 degreeC-520 degreeC, and a thermal expansion coefficient exists in the range of ^{62-110x10 <-7>} / ^degreeC .

In the glass powder composition, when the PbO is less than 43 wt%, the softening temperature is high, so that the fluidity is lowered due to fluidity. easy to do. In addition, when SiO ₂ is 21 wt% or more, the softening temperature is high, and thus the sintering degree is lowered. When B ₂ O ₃ + Bi ₂ O ₃ is 25 wt% or more, the softening point is increased and fluidity is inferior. In addition, when Al ₂ O ₃ is 7 wt% or more, the softening temperature is high. When ZnO is 35 wt% or more, the viscosity change is moderate at high temperatures. When Na ₂ O + K ₂ O + Li ₂ O is 15 wt% or more, If the crystallinity is increased and BaO + CaO + MgO + SrO is 15 wt% or more, the softening temperature is increased, resulting in poor fluidity.

In addition, when the content of the glass powder with respect to the entire paste in the paste is 1 wt% or less, incomplete firing is made, and the electrical resistivity is high, and when it is 10 wt% or more, the glass component is too much in the calcined body of the silver powder, thereby increasing the electrical resistivity. Too high.

The glass softening temperature of the glass powder is 320 ℃ ~ 520 ℃, the thermal expansion coefficient is in the range of 62 ~ 110 × 10 ^-7 / ℃.

When the glass softening temperature of the glass powder is 520 ° C or higher, the fluidity is lowered and the plasticity is lowered. When the glass softening temperature is 320 ° C or lower, the fluidity is too high and the plasticity is lowered. When the thermal expansion coefficient of the glass powder is 62 × 10 ⁻⁷ / ° C. or less, a short circuit occurs during firing of the formed electrode, and when 110 × 10 ⁻⁷ / ° C. or more, the straightness of the formed electrode is reduced.

The electrode paste for a plasma display panel back plate exhibits an electrical resistivity of 4.0 x 10 ^-6 Pa.cm or less even when fired at a low temperature of 500 to 550 占 폚.

In the above-mentioned electrode paste for plasma display backplane, the organic material occupying a weight fraction of 9 to 50 wt% is 2 to 7 wt% of binder, 4 to 35 wt% of solvent, 3 to 15 wt% of plasticizer, thixotropic agent + It is comprised from 0-2.5 wt% of a dispersing agent + a leveling agent.

In the above-mentioned electrode paste for plasma display backplane, the binder component occupies 2 to 7 wt% in the total paste, and cellulose acetate, cellulose acetate butylate as the cellulose ester compound, ethyl cellulose, methyl cellulose, and hydrate as the cellulose ether compound. As hydroxy floppy cellulose, hydroxy ethyl cellulose, hydroxy propyl methyl cellulose, hydroxy ethyl methyl cellulose, polyacrylamide, poly methacrylate, polymethyl methacrylate, polyethyl methacrylate vinyl, At least one of vinyl butyral, polyvinyl acetate and polyvinyl alcohol.

When the binder component is 7wt% or more, the electrode width at the time of one printing (the maximum width values of the calcined body fired after printing as shown in 15 of FIG. 2 and the minimum of the calcined body fired after printing as shown in 16 of FIG. 2) Since the ratio of the electrode height to the average value of the entire width values, hereinafter referred to as the electrode width, is printed as low as 4% or less, the number of prints to increase the line resistance below a certain value increases, and the binder component is 2 If it is less than wt%, it should be maintained between 2 and 7 wt% because the binder does not play the role of maintaining the shape of the electrode until firing.

In addition, the binder component acts as an owner to adjust the viscosity of the whole paste, and the viscosity of the whole paste should be 150,000 to 450,000 cps.

Viscosity of the electrode paste for the plasma display backplane is a value of the plastic spread ratio of the electrode (the maximum width (15 in FIG. 2) values of the fired electrode after printing the electrode for the screen mask electrode pattern width value on the glass substrate for the backplane). Increase in the average value), if the viscosity of the whole paste is 150,000 cps or less, the spread ratio is 105% or more, and if the viscosity of the paste is 450,000 cps or more, printability is poor, and Short circuit occurs frequently.

In the paste, the solvent component, which accounts for 4 to 35 wt% of the total paste, is butyl acetate, ethylene glycol mono ethyl ether, ethylene glycol mono phenyl ether, diethylene glycol mono ethyl ether, diethylene glycol mono butyl ether, diethylene glycol Mono butyl, ether acetate, ethylene glycol diethyl ether, tepinol, fine oil, diethylene glycol mono ethyl ether acetate, 2, 2, 4-trimethyl pentane-1, 3 diol diiso butyrate, 2, 2, 4 -Trimethyl pentane diol mono isobutylate, methyl isobutyl ketone, diisobutyl ketone, and the like.

In the paste, when the solvent component is 35 wt% or more, the paste viscosity is very low, which causes difficulty in printing, and when the solvent component is 4 wt% or less, the screen mask omission property of the paste deteriorates and As the unevenness increases, a problem arises in that the electric wire resistance of the electrode becomes higher than that of the printed area.

Said omission property pastes the sieve (13 of FIG. 1) mesh of the opening part (11 of FIG. 1) except the part covered with the oil agent (12 of FIG. 1) of the screen mask. How well does it pass? If the omission is poor, the unevenness of the paste does not pass well through the incomplete opening of the sheave (14 in FIG. 1), and the thickness of the print is not sufficient because the paste does not completely pass the mesh even in the non-incomplete opening. By lowering the electrical resistance is increased.

The degree of unevenness of the fired body of the electrode paste for the back plate of the plasma display panel may be expressed as 3CV, wherein the 3CV divides the back plate of the plasma display panel in which the electrode shape is formed by a printing method into 50 or more portions, and each portion thereof. The electrode maximum width (15 in FIG. 2) and the electrode minimum width (16 in FIG. 2) were measured, and the standard deviation (STDEV.) Of the values was divided by the average value, and then multiplied by 300.

The higher the 3CV value is, the higher the degree of unevenness is, and the lower the value is, the closer to the straight line. It has a value of 20 or less.

The thickness of the sintered body of the electrode for the rear panel of the plasma display panel may be represented by a thickness (%), wherein the thickness (%) is the thickness of the electrode formed in one printing, and the electrode width value formed in one printing. It is expressed as a percentage.

If the value of the thickness (%) is large, the cross-sectional area of the electrode formed per print increases, so the electric wire resistance is reduced, and the number of prints for realizing the desired electric wire resistance is reduced, which significantly reduces the process time and equipment investment cost. The thickness of the printed electrode for the back panel of the conventional plasma display panel is less than or equal to 3, but the thickness of the printed electrode for the back panel of the plasma display panel is 4 or more.

3CV, thickness (%), and spread rate, which are characteristic values of the electrode for the back panel of the plasma display panel, are important values that can be applied to the high quality plasma display panel back plate of the electrode paste. In order to be applicable to the back panel of the high-definition plasma display panel, it is possible to realize a uniform micro shape and to have low electrical wire resistance of the formed electrode. %) Represents low line resistance. In other words, the lower the spread ratio, 3CV, and the higher the thickness (%), the better the paste can be.

The electrode paste for the plasma display backplane contains a plasticizer, which accounts for 3 to 15 wt% of the entire paste, and includes diethyl phthalate, dibutyl phthalate, butyl benzyl phthalate, dibenzyl phthalate alkyl phosphate, polyalkylene glycol, poly It is characterized by consisting of a mixture of at least one of ethylene oxide, hydroxy ethyl alkyl phenol, tricresol phosphate, triethylene glycol diacetate, polyester compound.

When the plasticizer is 3wt% or less, flexibility and workability are inferior, and when the plasticizer is 15wt% or more, the physical property change of the whole paste to be obtained in the present invention described above is severe.

The electrode paste for the rear panel of the plasma display panel contains a thixotropic agent + leveling agent + dispersant 0 to 2.5 wt%.

When the content of the thixotropic agent + leveling agent + dispersant is 2.5 wt% or more, problems of poor omission, high spreading rate, and difficulty in forming paste occur.

The following is an experimental result of the electrode paste for the back plate of the plasma display panel.

Composition number Solid content Cellulose acetate butyrate Butylfine Carbitol + Aceoyl Tate Plasticizer Etc 3CV Spread (%) thickness(%) Printability Composition 1 70 2 23 4 One 9 104 7 x Composition 2 52.5 5 37 5 0.5 12 104 5 x Composition 3 70 3 23 3 One 13 104 6 x Composition 4 70 4 18 7 One 15 104 6 o Composition 5 70 6 18 4.5 1.5 17 102 4 o Composition 6 70 9 18 2 One 27 114 1.5 x

Composition number PbO SiO ₂ B ₂ O ₃ + Bi ₂ O ₃ Al ₂ O ₃ ZnO Na ₂ O + K ₂ O + Li ₂ O BaO + CaO + MgO + SrO Coefficient of Thermal Expansion (x 10 ^-7 / ℃) Short circuit Specific resistance (x 10 ^-6 Ω.cm) Remarks Composition 1 45 16 5.5 2.5 30 One 71 X Plastic composition of 520 ℃ plastic composition uses composition 4 of table 1. Composition 2 60 15 19 6 60 Occur O Composition 3 61 16 5.5 10 1.5 6 87 X Composition 4 66 16 10 2 6 74 O Composition 5 73 2 10 15 88 O Composition 6 75 6 10 3 6 104 O Composition 7 81 5 12 2 85 O Composition 8 85 3.5 6 5.5 87 O Composition 9 90 7 3 96 O Composition 10 15 18 17 3 25 7 84 X Composition11 7 26 25 6 31 5 50 Occur X Composition12 23 12 10 2 39 5 85 X Composition13 25 10 8 46 11 107 X

[Experiment 1] Change of Printing Characteristics by Organic Components

The print characteristics were tested by selecting the composition shown in Table 1. When the total paste was 100, each component was expressed in wt%, and the solid content was used in composition 4 in Table 2. Here, 3CV divides the back panel of the plasma display panel in which the electrode shape is formed by the printing method into 50 or more portions, and the maximum electrode width (15 in FIG. 2) and the minimum electrode width (16 in FIG. 2) are divided for each portion. Measured, the standard deviation of the values (STDEV.) Divided by the average value, multiplied by 300, the lower the value is the straightness, the spread rate is the electrode width of the screen mask (11 in Fig. 1) printed electrode Multiplying the average value of the maximum width (15 in FIG. 1) of the product by multiplying by 100, the spreadability of the paste.

The thickness (%) is the maximum width values of the post-fired calcined body represented by 15 of FIG. 2 and the minimum width of the post-fired calcined body represented by 16 of FIG. 2. Divided by the average of the width values, multiplied by 100, proportional to the electrode cross-sectional area.

Easiness of printing is indicated by (circle) when it is the same as or more than a commercial paste, and x when it is insufficient.

[Experiment 2] Plastic Body / Electrical Property Change According to Glass Powder Components

The plastic body / electrical properties were tested by selecting the composition shown in Table 2. When the total glass component was 100, each component was expressed in wt%, and the organic composition was used in Composition 4 of Table 1. Here, the short circuit is a breakage phenomenon in the fired electrode, the specific resistance is represented by ○, and more than 4.0 × 10 ^-6 Pa.cm or less.

[Experiment 3] Comparison of electrical resistivity according to firing temperature of paste according to the present invention and conventional paste

Table 3 shows the results of comparing the electrical resistivity of the paste according to the present invention with the different firing temperatures. The composition of solid content and the organic substance used the composition 4 of Table 1, and the composition 4 of Table 2. Resistivity is 4.0 × 10 ^-6 Ω.cm or less temporary ○, 4.0 × 10 ^-6 Ω.cm was represented by at least temporarily ×.

division Paste according to the present embodiment Paste 1 by the prior art Paste 2 by the prior art 570 ℃ ○ ○ ○ 560 ℃ ○ ○ ○ 550 ℃ ○ ○ × 530 ℃ ○ × × 510 ℃ ○ × × 500 ℃ ○ × ×

As described above, the electrode paste for the plasma display panel back plate according to the present invention can be applied to a high-quality plasma display panel of V-G (640 × 480) or more because uniform micro shape molding is possible.

In addition, since the printing thickness per circuit is high, the number of repetitive prints for lowering the line resistance is about half of the conventional printing electrodes for the back panel of the plasma display panel, thereby reducing the process time and equipment investment of the printing electrodes.

In addition, since the firing temperature is low and the back plate glass warping does not occur at the time of firing, it is also applicable to yield increase and general soda lime glass.

In the above, the present invention has been described according to an embodiment of the present invention, but the present invention has been changed and modified by those skilled in the art without departing from the spirit of the present invention. Belongs to.

Claims (3)

In the electrode paste for a plasma display panel back plate which is baked at 550 ℃ or less to be produced as an electrode, The entire paste of the electrode is composed of 49 to 85 wt% of silver powder, 1 to 10 wt% of glass powder, and 9 to 50 wt% of organic material. The silver powder has an average particle diameter of 0.5 ~ 17㎛, the shape is provided in at least one shape selected from spherical, acicular, plate-like and amorphous. , The glass powder has an average particle diameter of 0.5 to 17 µm, the composition of PbO 43 to 91 wt%, SiO ₂ 0 to 21 wt%, B ₂ O ₃ + Bi ₂ O ₃ 0 to 25 wt%, Al ₂ O ₃ 0 -7 wt%, ZnO 0-20 wt%, Na ₂ O + K ₂ O + Li ₂ O 0-15 wt%, BaO + CaO + MgO + SrO 0-15 wt%, glass softening temperature is 320 ° C ~ 520 ℃, the coefficient of thermal expansion is 62 ~ 110 × 10 ^-7 / ℃, The organic material is a binder 2 ~ 7 wt%, solvent 4 ~ 35 wt%, plasticizer 3 ~ 15 wt%, thixotropic agent + dispersant + leveling agent 0 ~ 2.5 wt% for the back panel of the plasma display panel Electrode paste. The method of claim 1, An electrode paste for a back panel of a plasma display panel, wherein the viscosity of the entire paste is 150,000 to 450,000 cps. The method of claim 1, Electrode paste for back panel of plasma display panel, characterized in that the resistivity of the electrode fired at 500 ~ 550 ℃ is 4.0 × 10 ^-6 Ω.cm or less