KR100352160B1 - Method of manufacturing a sealing paste for manufacturing a flat display panel in a vacuum and a method for sealing a flat display panel by using the sealing paste - Google Patents

Abstract

The present invention provides a method of manufacturing a sealing paste used for in-line sealing, pumping and sealing-off in-line in a process for manufacturing a flat panel display device. It is about.

The method for producing a sealing paste according to the present invention comprises the steps of uniformly mixing a crystalline mounting powder containing PbO, ZnO, B2O3 as a main component, and a glass type mounting powder containing PbO, B2O3, SiO2 as a main component at a predetermined ratio; After mixing the predetermined additive consisting of a binder, a surfactant, and the like so that the mixed mounting material powder has a predetermined viscosity and printing characteristics, and uniformly mixed and dispersed by a predetermined dispersing means.

Description

Method of manufacturing a sealing paste for manufacturing a flat display panel in a vacuum and a method for sealing a flat display panel by using the sealing paste}

The present invention provides a method of manufacturing a sealing paste used for in-line sealing, pumping and sealing-off in-line in a process for manufacturing a flat panel display device. It is about.

As a method for improving the degree of vacuum inside the flat panel display device, a sealing paste is formed at the edge of the front panel or the rear panel of the flat panel display device in the air, followed by a plastic heat treatment process, and the front panel and the back panel are heated in a vacuum chamber. A vacuum inline method for performing a sealing process by mounting on a support plate to melt the sealing paste has been studied.

The encapsulation and encapsulation method by the vacuum in-line method is superior to the conventional method involving a decrease in the degree of vacuum and deterioration of device characteristics due to impurity gas generated during heat treatment.

In general, there are two types of mounting materials, the main component of the sealing paste used for sealing or encapsulating in the vacuum in-line method, a glass type and a crystalline type.

The glass-type mounting material is a glass-type mounting material containing Pb in which a flow of material occurs in a melting step and a molten state occurs several times at the same temperature, and the crystalline mounting material has a hardness upon melting. It is a glass-type mounting material containing Pb which occurs and has a melting temperature higher than the first time upon melting.

However, the two mounting materials have the following problems when melting occurs in a vacuum. That is, the glass-type mounting material undergoes a calcining heat treatment process in the air, and when it is melted (fired) again in vacuum, the vapor pressure is increased, so that some of the components of the mounting material evaporate and bubbles are generated. Maintaining the degree of vacuum inside becomes difficult.

In addition, when the crystalline mounting material is subjected to a plastic heat treatment process in the air and then melted (fired) and cooled again in a vacuum, cracks or pin-holes are generated as crystallization occurs, thereby causing Maintaining the degree of vacuum becomes difficult.

1 is an embodiment of a conventional vacuum inline sealing and evacuation and encapsulation device.

2 is a partially enlarged view of a display device showing a pore state which is a problem of the prior art, FIG. 3 is a partially enlarged view showing a partially unsealed state which is a problem of the prior art, and FIG. 4 is a pin of the related art. -Partial enlarged view showing a hole state, Figure 5 is a graph showing a gas leak state with time and pressure of the display device having the pin-hole, Figure 6 is a part showing a partially cracked state which is a problem of the prior art It is an enlarged view.

7 is a graph showing a gas discharge state with respect to the heat treatment temperature and pressure for the sealing paste of the prior art.

In addition, Figure 9 is a temperature distribution of the low temperature firing temperature (280 ℃) according to the present invention and the resulting vacuum degree change, Figure 10 is a result graph for the leak test (leak test) of the display panel made accordingly.

FIG. 11 is a temperature distribution diagram of a low temperature firing temperature (290 ° C.) and a vacuum change according to the present invention, and FIG. 12 is a result graph of a leak test of a display panel made accordingly.

The present invention aims to produce a sealing and sealing mounting material applicable to a vacuum in-line method and a sealing paste based on the mounting material, which are free from pores and pin-holes, which are problems of the prior art. .

Other objects and advantages of the present invention will become more apparent from the following detailed description of the invention and the accompanying drawings.

1 is an embodiment of a conventional vacuum inline sealing and evacuation and encapsulation device.

2 is a partially enlarged view of a display device showing bubbling, which is a problem of the prior art;

3 is a partially enlarged view showing a partially unsealed state which is a problem of the prior art;

4 is a partially enlarged view showing a pin-hole state which is a problem of the prior art.

FIG. 5 is a graph illustrating a gas leak state according to time and pressure of the display device having a pin-hole according to FIG. 4.

6 is a partially enlarged view showing a partially cracked state which is a problem of the prior art.

7 is a graph showing the gas release state versus heat treatment temperature and pressure for a sealing paste of the prior art.

8 is a partially enlarged view of a state in which the sealing paste according to the present invention is sealed in a vacuum inline manner.

9 is a temperature distribution of the low temperature firing temperature (280 ℃) according to the present invention and the resulting vacuum degree change.

10 is a graph showing the results of a leak test of a display panel made under a low temperature firing temperature (280 ° C.) according to the present invention.

11 is a temperature distribution of the low temperature firing temperature (290 ° C) and the resulting vacuum change according to the present invention.

12 is a graph showing results of a leak test of a display panel made under a low temperature firing temperature (290 ° C.) according to the present invention.

<Brief description of the main parts of the drawing>

1 front panel 2 back panel

6 vacuum chamber

7 Vacuum holding means 8 First gas supply means

9 First supporting means 10 Heating means

11 1st position adjustment means 12 gas injection part

13 holes 14 heating means

15 Second supporting means 16 Exhaust and gas injection means

17 O-ring 18 Second position adjusting means

19 Cylinder 20 Encapsulant

21 Heating means 22 Third position adjusting means

23 Cooling means 24 Space

25 Pump system 26 Second gas supply means

27 Protruding Jaw 28 Getter Mount

29 Getter 30 Encapsulant

31 Getter heating means 32 Support means

33 4th position adjusting means 34 Support

The method for producing a sealing paste applicable to the vacuum inline method according to the present invention comprises a crystalline mounting material powder containing PbO, ZnO, and B2O3 as a main component, and a glass type mounting powder containing PbO, B2O3, and SiO2 as a main component. Uniformly mixing;

The mixed mounting material powder is a step of mixing a predetermined additive consisting of a binder, a surfactant and the like to have a predetermined viscosity and printing characteristics, and then uniformly mixed and dispersed by a predetermined dispersing means.

The crystalline mounting powder consists of 70 weight percent PbO, 15 weight percent ZnO, 10 weight percent B2O3, 2 weight percent SiO2, and a small amount of BaO and SnO2. 90 weight percent PbO, 10 weight percent B2O3, 1.5 weight percent SiO2, and a small amount of ZnO, BaO, Fe2O3, SnO2.

Preferably, the mixed powder of the crystalline mounting powder and the glass mounting powder comprises 80 weight percent PbO, 9.5 weight percent B2O3, 7.5 weight percent ZnO, 2 weight percent SiO2, 0.5 weight percent SnO2, 0.1 weight percent Fe2O3, and 0.05 weight percent BaO. At this time, the heat treatment conditions for applying the sealing paste to the glass substrate, the final achieved temperature during heating ranges from 280 ℃ to 300 ℃ It is preferable to adjust so that the temperature increase rate which heats to the said last achieved temperature may be 3 degreeC / min-5 degreeC / min, and the temperature reduction rate which cools from the said last achieved temperature shall be 3 degreeC / min-5 degreeC / min. .

The steps in the case of applying the sealing paste according to the present invention to the sealing of a flat panel display device will be described by way of example. That is, the crystalline package powder mainly containing PbO, ZnO and B2O3, and PbO and B2O3. And a sealing paste in which a glass-type mounting material powder containing SiO 2 as a main component is mixed, for sealing a flat panel display element under vacuum.

Forming a sealing paste on a predetermined portion on at least one of two glass substrates constituting the flat panel display element and then performing heat treatment;

Mounting the heat-treated substrate and the remaining substrate in a vacuum chamber at a predetermined distance from each other;

Maintaining the degree of vacuum in the vacuum chamber at high vacuum;

Coupling the two substrates to each other by separate positioning means;

Filling the interior of the vacuum chamber with an inert gas;

The heating is performed by heating the substrate on which the sealing paste is formed by a separate heating means to seal the two substrates by melting the sealing paste.

The heating means may be a method of heating by a heater, a method of scanning and heating a laser, and heating by an anodic bonding method in which heating and a voltage are applied and combined.

FIG. 8 is a partially enlarged view of a state in which the sealing paste according to the present invention is sealed in a vacuum inline manner. Pores and cracks, which appeared to be a problem of the prior art, were not found.

More specifically, frit powder is mixed in an appropriate ratio (50:50 or 60:40) to form a paste by mixing with a binder and a solvent, and then applied with a vacuum in-line mounting material to bubbles and cracks. The invention relates to a process technology capable of preventing a crack from occurring and enabling a mounting temperature at a low temperature in the range of 280-300 ° C. by firing in a vacuum chamber.

An embodiment according to the present invention is as follows.

1. Preparation of frit paste

1-1) Powder Mixing: Crystalline mounting powder (wt%: PbO = 72.26, ZnO = 15.06, SiO2 = 1.90, B2O3 = 9.83, BaO = 0.08, SnO2 = 0.87) and glass mounting powder (wt%: PbO = 89.15, ZnO = 0.04, SiO2 = 1.40, B2O3 = 9.16, BaO = 0.01, Fe2O3 = 0.19, SnO2 = 0.04) and mix in the range 40:60 to 60:40.

At this time, the composition ratio of the mixed frit paste powder is approximately PbO = 78-84, ZnO = 5.0-10.0, SiO2 = 1.50-1.80, B2O3 = 9.0-10.0, BaO = 0.03-0.06, Fe2O3 = 0.07-0.12, SnO2 = 0.30-0.60 wt%.

1-2) Paste Preparation: Mix frit powder and vehicle (solvent mixed with nitro cellulose (NC) and butyl carbitol acetate (BCA)) in a weight ratio of 6: 1 to 12: 1 Mill and mix evenly with a ball miller for several hours.

2. Dispensing

The mixed frit paste is applied along the edge of the glass plate using a dispenser.

3. Pre-baking Process

The coated glass substrate is heat-treated in an electric furnace to burn off the solvents contained in the paste. The temperature at this time is advanced for several minutes at 400 degreeC or more.

4. Place the front and back glass plates into the vacuum chamber.

It may also be transported and mounted in-line from the previous chamber.

5. Carry out the exhaust process to secure more than 10 ^-6 torr of vacuum.

6. Post-baking process

The temperature of the heating means for heating the glass plate is raised.

At this time, the temperature increase rate is about 3-5 ℃ / min, the final achieved temperature is about 280 ℃ to 300 ℃. Wait for the vacuum to return to the 10 ^-6 torr range at the firing temperature. Move the front or back plate vertically to mount two glass plates. Apply a little press for sufficient mounting. Then raise the temperature. The ascent rate is in the range of -3 ° C to -5 ° C per minute.

7. Encapsulation Process

In the case of PDP, the gas is filled through the gas inlet, and then the frit formed around the inlet is calcined at the above temperature condition to perform the encapsulation process.

In the sintering process according to the prior art, the exhaust conductivity is typically limited through the glass tube, thereby limiting the exhaust conductivity. Therefore, the degree of vacuum inside the panel is 100 times lower than the degree of vacuum inside the chamber.

In addition, a high temperature firing having a temperature range of 420-450 ° C. has a serious problem that thermal deformation and viscosity change occur during firing of soda glass, which is usually used as a substrate, at the high temperature.

However, in the present invention, since the firing process can be performed at a low temperature in the range of 280-300 ° C., not only the characteristics of the panel but also a significant yield improvement in the manufacturing process are brought.

9 to 12 show the experimental results of the low-temperature firing process according to the present invention.

9 is a temperature distribution of the low temperature firing temperature (280 ° C) and the resulting vacuum degree change according to the present invention,

FIG. 10 is a graph showing results of a leak test of a display panel made under a low temperature firing temperature (280 ° C.) according to the present invention.

11 is a temperature distribution of the low temperature firing temperature (280 ℃) according to the present invention and the resulting vacuum degree change,

12 is a graph showing results of a leak test of a display panel made under a low temperature firing temperature (280 ° C.) according to the present invention.

In particular, in the low temperature firing process according to the present invention, the final achieved temperature during heating is controlled to be in a range between 280 ° C. and 300 ° C., and the temperature increase rate for heating to the final achieved temperature is 3-5 ° C./min. The temperature reduction rate of cooling from the final attained temperature was adjusted to 3-5 ° C./min.

The present invention can be variously modified and can take various forms and only the specific embodiments thereof are described in the detailed description of the invention. It is to be understood, however, that the present invention is not limited to the specific forms mentioned in the detailed description of the invention, but rather includes all modifications, equivalents, and substitutions within the spirit and scope of the invention as defined by the appended claims. It should be understood to do.

When the vacuum in-line method is used for the sealing and encapsulation technology, which has been a major obstacle to mass production of flat panel display devices, it is possible to mass-produce by lowering manufacturing cost and shortening the process. There was a basic perception that it could be done, but it was not possible to develop a sealing paste having excellent properties under a vacuum process, which was practically impossible.

However, when the sealing paste proposed in the present invention is used, it has a clean sealing state without problems such as pores and cracks, which is a problem of the prior art, and thus a large amount of flat panel display devices is realized by fully realizing the sealing and sealing process by vacuum inline method. It brought a breakthrough in production.

Claims (9)

In the manufacturing method of the sealing paste for sealing and sealing by vacuum in-line method for manufacturing a flat panel display device, Uniformly mixing a crystalline mounting material powder containing PbO, ZnO, and B2O3 as a main component, and a glassy mounting material powder mainly containing PbO, B2O3, and SiO2 at a predetermined ratio; And Sealing paste, comprising the steps of mixing a predetermined additive consisting of a binder and a surfactant and the like uniformly by a predetermined dispersing means so that the mixed mounting material powder has a predetermined viscosity and printing characteristics Method of preparation. The method of claim 1, wherein the crystalline mounting powder is composed of 70 weight percent PbO, 15 weight percent ZnO, 10 weight percent B2O3, 2 weight percent SiO2, small amounts of BaO and SnO2, The glass-type mounting powder comprises 90 weight percent PbO, 10 weight percent B2O3, 1.5 weight percent SiO2, and a small amount of ZnO, BaO, Fe2O3, SnO2. 3. The mixed powder of the crystalline mounting powder and the glass mounting powder according to claim 2, wherein the mixed powder of the crystalline mounting powder and the glass mounting powder comprises 80 weight percent PbO, 9.5 weight percent B2O3, 7.5 weight percent ZnO, 2 weight percent SiO2, 0.5 A weight percent SnO2, 0.1 weight percent Fe2O3, and 0.05 weight percent BaO, characterized in that the manufacturing method of the sealing paste. delete delete delete delete delete The heat treatment condition according to any one of claims 2 to 3, wherein the heat treatment conditions for applying the sealing paste to a glass substrate include: Upon heating, the final achieved temperature is adjusted to be in the range between 280 ° C and 300 ° C, The temperature increase rate which heats to the said last achieved temperature shall be 3 degrees C / min-5 degrees C / min, The temperature reduction rate cooled from the said last achieved temperature is 3 degreeC / min-5 degreeC / min, The manufacturing method of the sealing paste characterized by the above-mentioned.