KR20030020178A - Method for framing a plasma display panel - Google Patents

Abstract

PURPOSE: A method for assembling a plasma display panel is provided to achieve improved exhaust conductance and allow for an ease of mass production of a PDP. CONSTITUTION: A method for assembling a plasma display panel comprises a first step of depositing a sealing agent(12) including frit on one of an upper substrate and a lower substrate where a predetermined pattern including a barrier rib(10) is formed, in such a manner that the deposited sealing agent has a height higher than the height of the barrier rib; a second step of disposing a variable spacer(14) between the upper substrate and the lower substrate, wherein the spacer has a height lower than the height of the barrier rib and which expands or contracts in accordance with the temperature; a third step of aligning the upper substrate and the lower substrate, and transferring upper and lower substrates into a furnace; a fourth step of thermally expanding the spacer to have a height higher than the height of the barrier rib by raising the internal temperature of the furnace to a first temperature level higher than the softening point and lower than the melting point of the sealing agent, and contracting the sealing agent to have a height equal or similar to the height of the spacer; a fifth step of sealing upper and lower substrates under the first temperature level; a sixth step of permitting an end of the spacer to be disposed at the position higher than a predetermined height by thermally contracting the spacer; a seventh step of exhausting air from upper and lower substrates by reinforcing the sealing agent while maintaining the exhaust temperature for a predetermined time period; an eighth step of contracting the sealing agent to have a height equal or similar to the height of the barrier by raising and lowering the internal temperature of the furnace; and a ninth step of contracting the spacer to have a height lower than the height of the barrier rib by lowering the internal temperature of the furnace to the normal temperature.

Description

Assembly method of plasma display panel {METHOD FOR FRAMING A PLASMA DISPLAY PANEL}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel, and more particularly, to a method for assembling a plasma display panel, which can achieve mass production while achieving the same exhaust effect as a vacuum exhaust path.

In general, a plasma display panel (PDP) is hereinafter referred to as 'PDP' for convenience, and is a display device that implements a predetermined image by using vacuum ultraviolet rays generated by gas discharge for emitting phosphors. It is getting into the spotlight as next generation thin display device.

Such a PDP typically includes a pair of upper and lower substrates on which an electrode is formed in a predetermined pattern to face each other, and any one of the upper and lower substrates is provided with means for exhaust and discharge gas injection.

Hereinafter, a process of assembling the substrates will be described.

Apply a sealing agent such as frit formed by mixing glass powder and adhesive at a desired position to seal the one of the upper and lower substrates on which the pattern is formed, and then pre-fired. Align the upper and lower substrates while observing the alignment marks provided on each substrate, and after the alignment is completed, clamp both substrates using a jig and then use a known general sealed exhaust passage (exhaust passage in which the exhaust process is performed under atmospheric pressure). The heating, sealing, exhausting, gas injection, and the like in the sealed exhaust passage.

1 shows a temperature profile in a sealed exhaust passage according to the prior art, and initially the interior of the sealed exhaust passage is maintained at about 25 ° C. under atmospheric pressure.

In this state, a heating step is performed, and the heating step is performed at a maximum heating rate (about 3 ° C./min) for a predetermined time (about 2 hours and 20 minutes) within the limit to prevent breakage of the panel ( Section 1).

Afterwards, the sealing process is performed for 20 minutes at a temperature not exceeding the melting temperature of the frit but not causing the crack of magnesium oxide (MgO), that is, approximately 440 ° C (section 2). The temperature reduction step of lowering to the exhaust temperature at the same speed is performed (section 3).

When the temperature of the enclosed exhaust furnace is lowered to the exhaust temperature, the exhaust process is performed for 10 hours at the softening point of the frit, that is, at the maximum temperature condition of about 355 ° C or lower (approximately 350 ° C) (section 4 to 8), and the exhaust Upon completion, the cooling process will take place for 4 hours at the maximum cooling rate allowed by the installation (section 9).

When the cooling process is completed, the temperature of the enclosed exhaust furnace is lowered to about 25 ° C., which is an initial temperature, and thereafter, a preheating process of preheating the exhaust pipe at the temperature state (section 10), and tipping off the exhaust pipe after the discharge gas is injected. A gas injection process is performed (section 11).

However, according to the assembly process according to the temperature profile of FIG. 1, when the discharge cell structure is complicated, it takes a long time to reach the vacuum because the exhaust conductance is much smaller than the periphery of the exhaust port, and discharged inside the discharge cell during heating exhaust. There is a problem that outgassing gas (including air) is not easily discharged to the outside, and this problem occurs more seriously in the barrier rib structure in which all sidewalls of the discharge cells are blocked.

In order to solve this problem, Japanese Patent Laid-Open No. 9-251839 uses a spacer during the exhaust process so that the upper end of the partition wall does not touch the upper plate, while the exhaust assembly keeps the heating exhaust passage in a vacuum state during the exhaust process. Is disclosed.

By the way, the Japanese patent has the effect of significantly improving the exhaust conductance of each discharge cell, but it is necessary to put a large number of panels in a vacuum chamber, heat the panels arranged in multiple layers in a vacuum, and after the exhaust process is completed Due to the problem of removing the spacer, mass production is not easy, and the substrate sealing agent must be heated in a vacuum state, so that air dissolved in the molten sealing agent foams and the sealing property is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a plasma display panel assembly method which is easy to mass produce while achieving the same exhaust effect as a vacuum exhaust path.

1 shows a temperature profile in a sealed exhaust passage according to the prior art;

2 shows a temperature profile in a sealed exhaust passage in accordance with the present invention.

3A-3E are comparative comparisons of variable spacers, sealants, and barrier heights according to the temperature profile of FIG.

4a to 4c are views showing various embodiments and arrangement of the variable spacer according to the present invention.

The above object of the present invention is to place a variable spacer having a height below the partition wall at room temperature and varying in height by thermal expansion and contraction according to the temperature between the upper and lower substrates, and after aligning the upper and lower substrates, both substrates are aligned. Is transferred into the sealed exhaust path where the exhaust process is performed under atmospheric pressure, and in the exhausting step, the end of the variable spacer is positioned at a position above the partition wall end, and after the exhaust is completed, the end of the variable spacer is located at a position below the partition wall end. It is achieved by the assembly method of the plasma display panel to assemble the upper and lower substrates as possible.

Hereinafter, a panel assembly method of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 illustrates a temperature profile in a sealed exhaust path according to the present invention, and FIGS. 3A to 3E show comparatively comparing heights of a variable spacer, a frit, and a partition wall according to the temperature profile of FIG. 2.

When a top and bottom substrate (not shown) having a predetermined pattern including the partition 10 is provided, glass powder, adhesive, and the like are placed at a desired position for sealing one of the substrates. After applying a sealing agent 12 such as frit formed by blending and prebaking, the sealing agent 12 is applied to a height of at least the height of the partition wall (10).

When the application of the sealant 12 is completed, a variable spacer 14 having a variable height is disposed between the upper and lower substrates by thermal expansion and contraction according to temperature, and the variable spacer 14 is less than or equal to the partition 10 at room temperature. It is preferable to have a height of (see Figure 4a), one end of the spacer 14 can be fixed to the lower plate provided with the partition wall (10).

When the arrangement of the variable spacer 14 is completed, the upper and lower substrates (not shown) are aligned while observing an alignment mark provided on each substrate, and when the alignment is completed, both substrates are used by using a jig (not shown). Is clamped and then transferred to a known general enclosed exhaust path (meaning that the exhaust process is performed under atmospheric pressure), and in the enclosed exhaust path (not shown), heating, encapsulation, exhaust, Processes such as gas injection are performed.

In detail, the inside of the sealed exhaust path (not shown) is maintained at about 25 ° C. under atmospheric pressure, in which case the spacer 14 provided on the lower substrate (not shown) transferred by the jig and the sealing agent ( 12, the partition wall 10 maintains the height as shown at the start of the interval 1 of FIG.

In this state, the inside of the sealed exhaust path (not shown) is heated at the maximum heating rate (approximately 3 ° C./min) for a predetermined time (approximately 2 hours 20 minutes) within the limit to prevent panel damage. The internal temperature of the exhaust passage is raised to a first set temperature (approximately 440 ° C.) above the softening point (355 ° C.) of the sealing agent 12 and below the melting point (section 1 in FIG. 2).

As such, when the internal temperature of the sealed exhaust passage is elevated, the spacer 14 is thermally expanded to the maximum height of the partition 10 or more as shown in the section 2 time point in FIG. 3, and the sealing agent 12 is a variable spacer. It is reduced to the same or similar height as (14).

Thereafter, the sealing process is performed for about 20 minutes under the first set temperature (section 2 of FIG. 2), and when the sealing process is completed, the internal temperature of the sealing exhaust passage is less than the softening point (355 ° C) of the exhaust temperature (approximately 350 ° C). ) Is lowered at the same rate as the heating rate (about 3 ° C./min) (section 3 of FIG. 2).

When the temperature reduction step of the section 3 is completed, the variable spacer 14 and the sealing agent 12 are reduced in height due to temperature change as shown in the section 3 and 4 of FIG. 3. Since the height is higher than that of the barrier rib 10, the barrier rib 10 and the upper substrate (not shown) are kept spaced apart from each other.

Here, the partition wall 10 and the upper substrate (not shown) are preferably maintained at an interval of 10 μm or more in consideration of the exhaust conductance, while maintaining an interval of 1000 μm or less in consideration of the breakage of the upper substrate. Do.

Thereafter, while maintaining the exhaust temperature for a predetermined time, the sealing agent 12 is reinforced to exhaust air inside both substrates (section 4 of FIG. 2). In the section 4, the spacer 14 slightly contracts but the upper substrate ( Not shown) and the top of the barrier 10 remains still spaced apart (see FIG. 3C).

When sufficient exhaust air is generated, the temperature inside the sealed exhaust path (not shown) is raised to near the softening point (355 ° C.) of the sealing agent 12, and the temperature is lowered to the exhaust temperature below the softening point. 5-7), these sections (sections 5-7) are necessary to reduce the sealing agent 12 to the same or similar height as the partition wall 10 as shown in sections 5-8 of FIG.

At this time, the temperature rise (section 5), the maintenance (section 6) and the temperature-falling section (section 7) in the section is designed so that the sealing agent 12 is softened and pressurized, the outgassing due to the temperature rise in the section It is advantageous to have a section (section 8) capable of sufficiently removing outgas.

Thereafter, the internal temperature of the enclosed exhaust passage is lowered to room temperature at the maximum cooling rate allowed by the facility (section 9). When the process of the section 9 is completed, the variable spacer 14 as shown in sections 9 to 11 of FIG. 3 is completed. ) Is thermally reduced to the height of the partition wall 10 or less.

When the heat reduction of the variable spacer 14 is completed as described above, the exhaust pipe is preheated at the room temperature (section 10), the discharge gas is injected, and the exhaust pipe is tipped off (section 11).

As described in detail above, when the height of the spacer 14, the height of the sealing agent 12, and the height of the partition wall 10 according to the temperature of each section are Hs, Hf, and Hb, respectively, the start time of the section 1 Where Hs < Hb < Hf, but Hb < Hf < Hs from the end of section 1 to the end of section 4, Hs < Hf < Hb in sections 5-8, and Hs < Hf = in sections 9-11 Hb.

Therefore, in section 4, which is the exhaust stage, a constant space is maintained between the partition wall 10 and the upper substrate (not shown) to improve the exhaust conductance, and after the segment 9 where the exhaust stage is completed, the spacer 14 returns to the initial height. The spacer 14 can be easily returned to remove the spacer 14.

In addition, since the sealing and evacuation process of the panel is performed in a general encapsulation exhaust passage, problems that occur when using a vacuum exhaust passage, that is, a problem of having to put a plurality of panels in a vacuum chamber, a substrate arranged in multiple layers under vacuum The same exhaust effect as a vacuum exhaust path can be obtained while solving the problem of heating, difficulty in removing the spacer after its functioning, and foaming of the air dissolved in the molten sealing agent.

As described above, the variable spacer 14 that thermally expands and contracts in response to temperature change is a material that reacts sensitively to temperature change, for example, when the height of the barrier rib is 120 μm and the height of the spacer is 100 μm at room temperature, A material that thermally expands to about 180 μm may be used when the furnace interior is heated to a maximum temperature of approximately 450 ° C.

This is because the spacer 14 having a diameter of about 180 μm at the maximum temperature can have a height of approximately 170 μm at 350 ° C. at the exhaust temperature, so that the spacer 14 is sufficiently high compared to the partition wall 10 at the exhaust stage to exhaust. This is because conductance is improved.

In addition, the variable spacer 14 may be designed to be geometrically sensitive to temperature change by adjusting the aspect ratio associated with the thermal expansion characteristic of the material.

4A to 4C show various embodiments and arrangements of the variable spacers.

4A illustrates a variable spacer 14 formed in a loop shape. The spacer 14 may be disposed on the lower substrate 16 on the outer side of which the sealing agent 12 is applied, and is easy to handle. And the removal of the spacer is possible.

4B shows a bar-shaped variable spacer 14, which is disposed on the lower substrate 16 at the outer side of the sealing agent 12 in the same manner as the loop spacer. It is possible to prevent a problem that may occur due to a change in length due to temperature change, for example, a problem such as contact between the spacer and the sealing agent, and removal of the spacer is possible.

In addition, FIG. 4C shows that the variable spacer 14 is formed into a pallet. The spacer 14 is mixed with the sealing agent paste and then applied to the lower substrate 16 together with the sealing agent 12. And has the advantage of simplifying the process.

In the above, the case of assembling the upper and lower substrates by using a variable spacer that thermally expands and contracts according to temperature changes has been described as an example, but the present invention is not limited thereto.

That is, the present invention can be used as a spacer using a jig-shaped instrument that can vary the height mechanically, or a bi-stable instrument consisting of a sphere and a spring can be used as a spacer to those skilled in the art Self-explanatory

As described above, the present invention can be modified and practiced in various ways within the scope of the claims and the detailed description of the invention and the accompanying drawings, and it is natural that the present invention also falls within the scope of the present invention.

According to the method of assembling the plasma display panel according to the present invention as described above, the vacuum exhaust passage can be used by performing the sealing and exhaust operation in a general sealed exhaust passage and by using a variable spacer whose height varies with temperature. Solving the various problems that occur in the case and at the same time it is possible to improve the exhaust conductance in the exhaust step, there is an effect such as mass production possible.

Claims (7)

Applying a sealing agent such as frit to at least one of upper and lower substrates having a predetermined pattern including a partition wall to a height equal to or higher than the partition wall height; Arranging between the upper and lower substrates a variable spacer having a height equal to or less than a partition at room temperature and whose height varies by thermal expansion and contraction according to temperature; Aligning the upper and lower substrates, and then transferring the aligned substrates into the sealed exhaust path in which the exhaust process is performed under atmospheric pressure; The internal temperature of the sealed exhaust passage is raised to a first set temperature above the softening point of the sealant and below the melting point, thereby thermally expanding the variable spacer to a maximum height of at least the height of the partition wall, and the sealant has the same or similar height as that of the variable spacer. A heating step of shrinking the furnace; A sealing step of sealing the upper and lower substrates under the first set temperature; A temperature lowering step of lowering an internal temperature of a sealed exhaust path to an exhaust temperature below a softening point and thermally contracting the spacers such that an end portion of the variable spacer is positioned at a predetermined height or more from a partition end; An exhausting step of exhausting air inside both substrates by strengthening the sealing agent while maintaining the exhaust temperature for a predetermined time; Reducing the sealing agent to a height equal to or similar to that of the partition wall by raising the internal temperature of the sealed exhaust path to near the softening point and then to the exhaust temperature below the softening point; Reducing the variable spacer below the height of the partition by lowering the internal temperature of the sealed exhaust path to room temperature; Assembly method of a plasma display panel comprising a. 2. The method of assembling a plasma display panel according to claim 1, wherein in said exhausting step, a spacing of 10 to 10 ³ mu m is maintained between the upper substrate and the partition wall. The method of assembling a plasma display panel according to claim 1, wherein the variable spacer has a loop shape. The method of assembling a plasma display panel according to claim 1, wherein the variable spacer has a plurality of bar shapes. The method of assembling a plasma display panel according to claim 3 or 4, wherein the variable spacer is disposed outside the sealing agent. The method of claim 5, wherein the variable spacer is removed after the panel assembly is completed. The method of assembling a plasma display panel according to claim 3 or 4, wherein the variable spacer is formed in a pallet type in which the variable spacer is coated with a sealing agent.