JP2002293580A - Sealing glass tablet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sealing glass tablet for sealing a tip of a glass tube 1 and a panel part around an evacuation hole 3, without forming reentrance shape on the sealing glass 20, even in the case of sealing at lower temperature than proper temperature for sealing, for attaching the tip of the glass tube 1 to a panel part around the evacuation hole 3, formed on the panel 2 of a plane display like a plasma display panel. SOLUTION: The sealing glass tablet having the large diameter part 11 with large outer diameter and the small diameter part 12 with a small outer diameter is characterized in that a ratio of the height of the small diameter part 12 to the wall thickness of the small diameter part 12 [=the outer diameter of the small diameter part 12-the inner diameter of the inserting hole 13)/2], i.e., (height of the small diameter part/wall thickness of the small diameter part 12) is >=1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed glass tablet for attaching a glass tube as an exhaust pipe to a panel of a flat display device such as a plasma display panel (PDP).

[0002]

2. Description of the Related Art A flat display device such as a PDP is provided with a glass tube called an exhaust tube for the purpose of exhausting the interior of the device or filling it with gas after the exhaust. The glass tube is attached so that the position of the exhaust hole provided in the panel of the flat panel display and the opening at the tip of the glass tube coincide.

[0003] When mounting the glass tube, the inclination of the glass tube is minimized with respect to the panel so that the glass tube can be easily connected to the exhaust equipment, and the glass tube is mounted perpendicularly to the panel surface. It is required to attach it so that airtightness is maintained so as not to lower it. Further, in a later step, it is necessary to attach the glass tube to the panel with such strength that the glass tube is not broken or the attachment portion is not peeled off.

[0004] As a method of bonding a glass tube to a panel, a sealing glass tablet obtained by molding a glass powder into a simple ring is generally used. An insertion hole for inserting a glass tube is formed in the sealing glass tablet.The glass tube is inserted into this insertion hole, the tip of the glass tube is aligned with the position of the exhaust hole of the panel, and the sealing glass tablet is inserted. The glass tube is attached to the panel by baking at the sealing temperature and softening the sealing glass.

When exhausting after attaching a glass tube,
A relatively high temperature (e.g., 350
° C). At this time, about 350 ° C. is applied to the sealing glass so that the sealing glass is softened and deformed, the exhaust pipe moves to close the exhaust hole, and the sealing glass portion has a hole so that the airtightness is not impaired. There is a need for heat resistance that can fix the glass tube so that it does not move.

[0006]

In the exhaust pipe mounted as described above, since the exhaust pipe is mounted vertically to the panel, when a load is applied to the exhaust pipe, the panel and the exhaust pipe are separated from each other. The stress is most easily applied to the sealing glass to be connected. Therefore, from the viewpoint of dispersing such stress, it is preferable that the shape of the sealing glass after sealing has a shape such that the skirt spreads from the highest possible position of the exhaust pipe toward the panel. . Further, the wetting angle of the glass tube and the sealing glass is preferably 90 ° or less, and a shape in which the wetting angle exceeds 90 ° is called a reentrance shape. It is not preferable because stress concentrates on the reentrance portion and the glass tube breaks at this portion. Therefore, it is preferable to perform sealing so that the shape of the sealing glass after sealing does not become a reentrance shape.

[0007] Some phosphors used in flat panel display devices are weak to heat, and a low-temperature sealing property capable of sealing at a lower temperature has been required.
However, the use of glass that can be sealed at a low temperature is not preferable because the heat resistance is also lowered at the same time. Therefore, it is required to perform sealing at a low temperature using a conventionally used sealing glass material. However, if the sealing is performed at a low temperature, the sealing glass has poor fluidity, and the sealing glass and the exhaust pipe are not sealed. Has a reentrance shape, stress is concentrated on the glass tube, and the glass tube is easily broken.

[0008] An object of the present invention is to provide a liquid crystal display device even when sealing is performed at a temperature lower than the proper proper sealing temperature of the sealing glass.
An object of the present invention is to provide a sealing glass tablet which does not form a reentrance shape between a glass tube and a sealing glass.

[0009]

According to the present invention, a tip of a glass tube as an exhaust pipe is disposed around an exhaust hole formed in a panel of a flat panel display, and the tip of the glass tube is placed around the exhaust hole. A sealed glass tablet for sealing and attaching to a panel portion, wherein the sealed glass tablet has an insertion hole for inserting and passing a glass tube, and the glass tube is inserted through the insertion hole. It has a large-diameter large-diameter portion located closer to the tip of the glass tube when sealing and a small-diameter smaller-diameter portion located farther from the tip of the glass tube,
Wall thickness of small diameter part [= (outside diameter of small diameter part-inside diameter of insertion hole) /
The ratio of the height of the small-diameter portion to 2] (the height of the small-diameter portion / the thickness of the small-diameter portion) is 1 or more.

Since the sealed glass tablet of the present invention has the large diameter portion and the small diameter portion as described above, even if the tablet is sealed at a temperature lower than the proper sealing temperature, it is sealed with the glass tube. Sealing can be performed without forming a reentrance shape between the glasses.

FIG. 8A is a cross-sectional view showing a state where a glass tube is mounted on a panel of a flat panel display device using a sealed glass tablet of one embodiment according to the present invention.
As shown in FIG. 8A, the glass tube 1 is arranged around the exhaust hole 3 formed in the panel 2 so that the tip of the glass tube 1 is in contact with the exhaust hole 3. Around the distal end of the glass tube 1, a sealing glass tablet 10 is arranged. The sealing glass tablet 10 is formed with an insertion hole 13 for inserting and passing the glass tube 1, and the glass tube 1 is placed on the panel 2 while passing through the insertion hole 13.

The sealing glass tablet 10 is a glass tube 1
A large-diameter portion 11 having a large outer diameter located on the side near the tip of
And a small-diameter portion 12 having a small outer diameter located farther from the tip of the glass tube 1.

The thickness t of the small diameter portion 12 is represented by (outer diameter d ₁ of small diameter portion 12 -inner diameter d ₃ of insertion hole 13) / 2. As described above, the present invention is characterized in that the ratio h ₁ / t of the height h ₁ of the small diameter portion 12 to the thickness t of the small diameter portion 12 is 1 or more. The preferred value of h ₁ / t is 1.2 or more, more preferably 1.4 or more.

When the ratio of h ₁ / t is smaller than the above range, a reentrance shape is easily formed between the glass tube and the sealing glass. FIG. 8 (b) is the same as FIG.
Shows the state when the sealing glass tablet is heated and the sealing glass is softened and sealed. The sealing glass 20 after sealing has a shape as shown in FIG.
It has a conical shape that expands as it approaches panel 2.

FIG. 9A is an enlarged sectional view of a contact portion between the glass tube 1 and the sealing glass 20 shown in FIG. 8B. As shown in FIG. 9A, the wetting angle θ between the glass tube 1 and the sealing glass 20 is less than 90 °.

FIG. 9B is a cross-sectional view showing a case where a reentrance shape in which the wetting angle θ of the sealing glass 20 with respect to the glass tube 1 is 90 ° or more is formed. FIG.
As shown in (b), sealing glass 2 in contact with glass tube 1
When the reentrance shape is formed in the zero contact portion 21, stress is concentrated on the contact portion 21, and the glass tube 1 is easily broken.

FIG. 8 shows the sealing glass in the state after sealing.
From the viewpoint of forming the shape as shown in (b), it is conceivable that the sealing glass tablet before sealing is already formed in such a shape. However, when the sealing glass tablet is formed in such a conical shape as shown in a comparative example described later, a sharp edge portion is formed at an upper portion of the sealing glass tablet, and chipping is easily generated at this edge portion. If the powder generated by chipping adheres to the panel, it sticks to the panel during sealing and cannot be removed. Therefore, a shape that easily generates such a chip is not preferable.

Returning to FIG. 8A, in the present invention, the outer diameter d ₂ of the large-diameter portion 11 is equal to the inner diameter d ₃ of the insertion hole 13.
It is preferably at least 5 times, especially at least 2 times. By satisfying this condition, the outer diameter d ₂ of the large-diameter portion 11 becomes relatively large, so that when the sealing glass tablet is heated and flows and deforms, the bonding area with the panel 2 increases. For this reason, the sealing glass after sealing becomes difficult to peel off from the panel, and the glass tube 1 can be attached to the panel 2 more firmly.

In the present invention, the large diameter portion 11 and the small diameter portion 1
2 is preferably formed integrally. However, the large diameter portion 11 and the small diameter portion 12 are formed separately,
At the time of sealing, these may be used in combination.

FIG. 8 shows a sealed glass tablet of the present invention.
It is not limited to a two-stage shape having a large diameter portion and a small diameter portion as shown in (a). For example, a portion having an intermediate outer diameter is formed between the large diameter portion and the small diameter portion. Alternatively, it may be a sealed glass tablet having three or more steps.

The material of the sealing glass tablet in the present invention is not particularly limited as long as the glass tube can be sealed to the panel. Either crystalline glass or amorphous glass may be used, or a composite powder obtained by mixing a refractory filler with powder of crystalline glass or amorphous glass may be used. Further, a colorant may be mixed with these. For the purpose of obtaining high heat resistance, it is preferable to use crystalline glass.

The sealed glass tablet of the present invention can be generally produced by press-molding the above raw material powder. Further, in the present invention, chamfering may be performed on an edge portion between the outer peripheral surface and the upper surface of the large diameter portion and the small diameter portion.

The flat display device of the present invention is not particularly limited. For example, a plasma display panel (PDP), a field emission display (FED), a plasma addressed liquid crystal display (PALC), or a fluorescent display ( VFD)
Is mentioned.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in Table 1, Examples a to g
In addition, sealed glass tablets of Comparative Examples hl were prepared.
The following glass was used as a material for the sealing glass tablet.

LS-0206: Nippon Electric Glass Co., Ltd. amorphous composite glass, recommended sealing temperature 450 ° C., coefficient of thermal expansion 72
× 10 ^-7 / ° C, yield point 353 ° C ・ LS-7105: crystalline glass manufactured by NEC Corporation, recommended sealing temperature 450 ° C, thermal expansion coefficient 85 × 10 ^-7 / ° C ・ LS-3081: NEC Glass Amorphous composite glass, recommended sealing temperature 410 ° C, coefficient of thermal expansion 74 × 10 ^-7 /
° C, yield point 320 ° C The sealing glass tablets of Examples a to f have a shape as shown in Fig. 1A, and the dimensions are as shown in Table 1. As shown in FIG. 1A, the sealing glass tablet 10 has a shape in which a small diameter portion 12 is formed on a large diameter portion 11.

Example g is a sealed glass tablet having a shape as shown in FIG. 2 (a), and its dimensions are as shown in Table 1. Comparative examples h, i, j, k, and l are shown in FIG.
(A), FIG. 4 (a), FIG. 5 (a), FIG. 6 (a), and FIG. 7 (a), and the dimensions are as shown in Table 1.

The sealing glass tablet is prepared by mixing a raw material powder and a binder, granulating the mixture in a granulator, filling the powder in a predetermined mold, press-molding, debinding the obtained molded body, and firing. It was manufactured by tying. The dimensions of the sealed glass tablet were measured using calipers.

A glass tube was sealed on the panel glass using a sealing glass tablet. As the panel glass, panel glass PP8 for PDP manufactured by NEC Corporation (coefficient of thermal expansion: 83 × 10 ⁻⁷ / ° C.) was used. As a glass tube, FE-2 manufactured by NEC Corporation (coefficient of thermal expansion 84 × 10
⁻⁷ / ° C.). The size of the glass tube is 4.9m outside diameter
m, inner diameter 3 mm, length 60 mm.

Using each of the above sealing glass tablets, a glass tube 1 and a sealing glass tablet 10 are arranged on a panel 2 as shown in FIGS. 1 (a) to 7 (a). The sealing glass tablet was heated and softened by heating to the sealing temperature shown in Table 1. FIGS. 1B to 7B are cross-sectional views showing the shape of the sealing glass 20 after sealing.

With respect to each Example and each Comparative Example, the sealing shape to the glass tube, the tube pulling strength, the breaking position, the heat resistance, and the chipping property were evaluated as follows. -Sealing shape to glass tube: The bonded portion between the glass tube and the sealing glass was observed, and those having a reentrance shape were evaluated as x, and those not recognized as o.

Tube pulling strength and breaking position: The glass tube bonded to the panel is pulled down by connecting it to a spring only at a portion 5 cm from the panel, the maximum load displayed at that time is measured, and the pipe pulling strength is measured. And Further, the state of destruction at that time was observed and indicated as a destruction position. Specifically, a glass panel or glass with no damage to the glass tube or sealing glass that has been destroyed is referred to as a “panel crack”. “Panel peeling” was indicated, and a broken glass tube was indicated as “tube broken”.

Heat resistance: The sealing panel with the glass tube sealed is set upright so that the glass tube is horizontal to the ground, and heated at 350 ° C. for 20 minutes in this state, and the glass tube is returned to its original state. Were not changed from the above angle, and x was changed.

· Scratch property: one sealed glass tablet
Put into an acrylic cylinder with a diameter of 30 mm and a length of 600 mm and fix both ends with rubber.
A tube lock test was performed in which the acrylic cylinder was tilted left and right for 0 cycles. After the test, the sealing glass tablet was evaluated as x when the chip was observed, and was evaluated as o when the chip was not observed.

Table 1 shows the evaluation results.

[0035]

[Table 1]

As is clear from Table 1, when the sealed glass tablets of Examples a to g according to the present invention were used, no reentrance shape was observed in the bonded portion between the glass tube and the sealed glass. Further, the pipe pulling strength was high, and there was no problem in heat resistance and chipping property.

On the other hand, in Comparative Example h in which the ratio of the small diameter portion height / the small diameter portion thickness was less than 1, a reentrance shape was observed, and the glass tube was broken in the tube pulling strength measurement test. It was a broken tube.

Comparative Example i in which the small diameter portion was not provided
Also in the sealed glass tablet, the reentrance shape was observed, and the glass tube was broken in a "broken tube" state. In Comparative Example j in which the outer diameter of the tablet was reduced, no reentrance shape was observed, but the pipe pulling strength was low.

In Comparative Example k, in which glass having a low recommended sealing temperature was used as the material of the sealing glass tablet, heat resistance was poor. In addition, the sealing glass tablet of Comparative Example 1 having a conical shape that becomes wider as approaching the panel as shown in FIG.

A comparison between Examples a to f, in which the ratio of the large-diameter portion outer diameter / inner diameter is 2 or more, and Example g, in which the ratio of the large-diameter portion outer diameter / inner diameter is less than 2, shows that in Example g, the panel Peeling has occurred, and the pipe pulling strength is low. Therefore, it is understood that the ratio of the large diameter portion outer diameter / inner diameter is preferably 2 or more.

In the above embodiment, the sealing glass tablet in which the large-diameter portion and the small-diameter portion are integrally formed is shown. However, the present invention is not limited to this, and as shown in FIG. The diameter part 11 and the small diameter part 12 are formed separately from each other, and when the glass tube 1 is sealed to the panel 2, the small diameter part 12 is superimposed on the large diameter part 11 and used in combination. The same effect can be obtained even with a sealing glass tablet.

[0042]

According to the present invention, even when the sealing is performed at a temperature lower than the proper proper sealing temperature of the sealing glass, the glass tube and the sealing glass tube have no reentrance shape. Can be sealed. Therefore, the adhesive strength to the panel can be increased. Further, according to the present invention, since glass having a high sealing temperature can be used, heat resistance can be improved. Further, according to the present invention, it is possible to provide a sealed glass tablet that is less likely to cause chipping during handling.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state when a glass tube is attached to a panel using a sealed glass tablet of an embodiment according to the present invention, and a cross-sectional view showing the shape of sealed glass after sealing (b). .

FIG. 2 is a cross-sectional view showing a state in which a glass tube is attached to a panel using the sealed glass tablet of the embodiment according to the present invention, and a cross-sectional view showing the shape of the sealed glass after sealing (b). .

FIG. 3 is a cross-sectional view showing a state when a glass tube is attached to a panel using a sealed glass tablet of a comparative example.
Sectional drawing (b) which shows the shape of the sealing glass after sealing.

FIG. 4 is a cross-sectional view showing a state in which a glass tube is attached to a panel using a sealed glass tablet of a comparative example.
Sectional drawing (b) which shows the shape of the sealing glass after sealing.

FIG. 5A is a cross-sectional view showing a state where a glass tube is attached to a panel using a sealed glass tablet of a comparative example.
Sectional drawing (b) which shows the shape of the sealing glass after sealing.

FIG. 6 is a cross-sectional view showing a state where a glass tube is attached to a panel using a sealed glass tablet of a comparative example.
Sectional drawing (b) which shows the shape of the sealing glass after sealing.

FIG. 7 is a cross-sectional view showing a state where a glass tube is attached to a panel using a sealed glass tablet of a comparative example.
Sectional drawing (b) which shows the shape of the sealing glass after sealing.

FIG. 8 is a cross-sectional view showing a state in which a glass tube is attached to a panel using the sealing glass tablet of the example according to the present invention, and a cross-sectional view showing the shape of the sealing glass after sealing (b). .

FIGS. 9A and 9B are cross-sectional views showing a shape of a bonding portion of a sealing glass bonded to a glass tube, wherein FIG. 9A shows a state where a reentrance shape is not formed, and FIG. Shows the state in which it is formed.

FIG. 10 is a sectional view showing a sealed glass tablet of still another embodiment according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Glass tube 2 ... Panel 3 ... Exhaust hole formed in panel 10 ... Sealing glass tablet 11 ... Large diameter part of sealing glass tablet 12 ... Small diameter part of sealing glass tablet 13 ... Insertion hole of sealing glass tablet 20 ... bonding portion d ₁ ... height h of the inner diameter h ₁ ... small-diameter portion of the outer diameter d ₃ ... insertion hole of the outer diameter d ₂ ... large diameter portion of the small diameter portion of the sealing glass 21 ... glass tube sealing glass ₂ … Height of large diameter part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4G061 AA01 AA02 BA03 BA11 CA02 CC03 CD02 CD06 CD16 5C012 AA05 AA09 BC03 5C040 HA02

Claims (5)

[Claims] An end of a glass tube as an exhaust pipe is arranged around an exhaust hole formed in a panel of a flat panel display device, and the end of the glass tube is sealed to a panel portion around the exhaust hole. A sealing glass tablet for attachment, wherein an insertion hole for inserting and passing the glass tube is formed, and the glass tube is close to a tip of the glass tube when sealing the glass tube through the insertion hole. A large-diameter part with a large outer diameter located on the side,
A small-diameter portion having a small outer diameter located on a side far from the tip of the glass tube, and a thickness of the small-diameter portion [= (outer diameter of small-diameter portion−inner diameter of insertion hole)
/ 2] (the height of the small diameter portion / the height of the small diameter portion /
A sealed glass tablet, wherein the thickness of the small diameter portion is 1 or more. 2. The sealed glass tablet according to claim 1, wherein the outer diameter of the large diameter portion is at least 1.5 times the inner diameter of the insertion hole. 3. The sealed glass tablet according to claim 1, wherein the large-diameter portion and the small-diameter portion are integrally formed. 4. The sealing glass tablet according to claim 1, wherein the large-diameter portion and the small-diameter portion are formed separately from each other, and are used in combination at the time of sealing. . 5. The flat display device is a plasma display panel (PDP), a field emission display (FED), a plasma addressed liquid crystal display (PALC), or a fluorescent display tube (VFD).
The sealed glass tablet according to any one of claims 1 to 4, wherein