JPH0757637A - Manufacture of flat display device - Google Patents

Abstract

PURPOSE:To improve reliability of a device by sealing a sealing part of a chip tube while extending it in the tube axis direction when a flat display device to which exhaust and sealing are applied is manufactured by a thin glass chip tube by using hard glass having a small thermal expansion coefficient as a raw material. CONSTITUTION:In a flat display device body supported on a support stand 21, that is, a chip tube 11 installed in a flat container 4, external force is imparted to the chip tube 11 in the direction for separating both end parts from each other along the tube axis between a connecting side end part 11a to the container 4 and a connecting side end part 11b with an exhaust system 25 on the opposite side of this. Thereby, the exhaust system 25 of the chip tube 11 is moved in the direction for separating from the support stand 21 in the tube axis direction of the chip tube 11 to the support stand 21. Or the support stand 21 is made movable in the direction for separating from the exhaust system 25 in the tube axis direction of the chip tube to the exhaust system 25. Since a remarkable thickness difference in a sealing part of the chip tube 11 and the occurrence of bending and the like can be avoided effectively, a higly reliable flat display device is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied, for example, to manufacturing a field emission type flat display device in which a slow electron beam phosphor is caused to emit light by using an electron beam from a field emission cathode to perform light emission display. And a preferred method for manufacturing a flat display device.

[0002]

2. Description of the Related Art A flat field emission display device (F) using a field emission microchip cathode is used as a display device with a low voltage excitation and a relatively high resolution.
ED) is under development.

In this flat type FED, a fine conical cathode, so-called microchip cathode, produced by fine processing is arranged so as to face the fluorescent screen, and electrons are extracted by an electric field to excite the fluorescent screen. The intended image display is performed.

In this flat type FED, for example, as shown in a schematic perspective view in FIG. 4, first and second glass panels 1 and 2 are arranged so as to face each other with a required small space therebetween. The frit seal 3 hermetically seals the peripheral portions, and the inner thickness is, for example, 0.3 mm.
The flat container 4 forms an extremely narrow flat airtight space.

On the inner surface of the first glass panel 1 which serves as the back plate of the flat container 4, as shown in the perspective view of the main part of FIG. 5, a stripe of Cr or the like extending in one direction, for example, the x direction is formed. Cathode electrodes 5 are formed in parallel, and stripe-shaped gate electrodes 7 made of Mo, W, etc. are orthogonal to the x direction of the extension direction of the cathode electrodes 5 with an insulating layer 6 such as SiO ₂ interposed therebetween. It is extended in the y direction and arranged in parallel.

FIG. 6 is an enlarged perspective view showing a cross section of a part of the main part of the FED. As shown in FIG. 6, the gate electrode 7 is formed at the intersection of each cathode electrode 5 and the gate electrode 7.
And a plurality of fine through holes 8 are formed through the insulating layer 6 and
A conical microtip cathode 9 is deposited on the cathode electrode 5 in each through hole 8.

The electrodes 5 and 7 and the insulating layer 6 are subjected to film formation by sputtering, vacuum evaporation, etc., patterning by photolithography, and formation of through holes 8. Then, oblique vapor deposition, sputtering, or the like is performed on the panel 1 while rotating the panel 1 to form a field-emission type microtip cathode 9 made of, for example, W and having a substantially conical shape in the through hole 8.

The second panel 2 is a front panel serving as a display surface, and a transparent electrode (not shown) is formed on the inner surface of the second panel 2, and red and green are used in a display device for performing color display, for example. The blue and blue phosphors R, G, and B are respectively formed so as to face the intersections of the electrodes 5 and 6 by, for example, an electrodeposition method. A so-called black matrix 10, which is a black layer for improving contrast, is applied between the phosphors R, G and B, for example.

In the FED having such a structure, a required positive voltage is applied to the gate electrode 7 with respect to the cathode electrode 5, and a required electric field is applied to the cathode 9, for example, 10 ⁶ to 10 ^6.
By applying an electric field strength of about ⁸ V / cm, electrons are emitted from the tip of the cathode 9, and the electrons are emitted from the phosphors R, G and the predetermined phosphors on the phosphor screen with the required kinetic energy given by the predetermined phosphor screen potential. B is excited to emit light.

In manufacturing such an FED, the flat container 4 is evacuated to a high degree of vacuum, and then the exhaust passage is sealed. Exhaust and sealing in this case are similar to exhaust in a normal cathode ray tube and the like, as shown in FIG. 4, an exhaust pipe so-called chip pipe 11 communicating with the inside of the container 4 is attached to the outer surface of the first panel 1, for example. The tip tube 1 is arranged along with
The side surface of the flat container 1 is connected to the through hole formed in the panel 1 so as to communicate with the flat space in the flat container 4, and the flat space in the flat container 4 is evacuated to a high degree of vacuum through the tip tube 11, The work of locally heating and melting and sealing the tip tube 11 at an appropriate portion in the axial direction of the tip tube 11 is performed in the state where the air is exhausted.

In the flat display device such as the FED, the flat container 4 formed by the panels 1 and 2 facing each other needs to be evacuated to a high degree of vacuum as described above. As described above, the inside of the flat container 4 has an extremely small thickness, so that the exhaust conductance during exhaust is extremely small. Therefore, it is desired that the tip tube 11 has an inner diameter as large as possible, and therefore, the tip tube 7 is desired to be as thin as possible.

On the other hand, in the flat display device in this FED, in forming the respective electrodes 5 and 7, the insulating layer 6, the cathode 9, etc., manufacturing steps such as vapor deposition, sputtering, etc., further patterning thereof, formation of through holes 8 etc. Since the manufacturing process such as RIE (reactive ion etching) is involved in the above, the flat container 4, that is, the panels 1 and 2 should not be deformed and the dimensional accuracy may be affected even after the heating process in each of these processes. In addition, glass having a small coefficient of thermal expansion is used, and accordingly, the tip tube 11 connected or fused to the flat container 4 is also constituted by a glass tube having a small coefficient of thermal expansion. .

In the manufacture of a conventional cathode ray tube type television picture tube of thermionic emission type, a terminal display device, etc., the tip tube used for the exhaust and sealing of the exhaust part is a relatively low melting point and thick glass. A tube is used, and in general, tip off of the tip tube, that is, heat fusion, is performed by electrothermal sealing for a thick tip tube and sealing by a burner for a thin tip tube.

However, since glass having a small coefficient of thermal expansion, such as a chip tube in a flat display device such as the FED described above, has a high melting point, fusion sealing for chip-off requires high temperature heating. Is something
The heating means for turning off the tip of the tip tube is a current-carrying heater that can be handled relatively easily and accurately from the viewpoint of mass productivity and can control the heating temperature relatively easily, and facilitates the automation of the manufacturing of the display device. Application of electrothermal sealing by heating is desired.

However, in this way, simply by heating the sealing portion of the chip tube 11 to melt-seal the chip tube, FIG. 7A shows a vertical sectional view thereof, and FIG. 7B shows FIG. 7A.
As shown in another vertical cross-sectional view in a plane orthogonal to the cross section of the chip tube, heating is performed in the sealing part of the chip tube by negative pressure in the chip tube in a high vacuum state in the melting part, that is, the sealing part 12. The glass wall in a molten or softened state is drawn in so as to bulge in the tube axis direction toward the connecting portion side of the chip tube 11 immediately before the sealing with the container 1. In this case, the drawing and the surface tension are It does not exhibit rotational symmetry with respect to the pipe axis of the tip pipe, and it deviates significantly from this symmetry, and an extremely thick reservoir 13 is formed in a part thereof, and an extremely thin bent portion 14 is generated accordingly. .

When a relatively thick and soft glass tip tube is used as usual, an extremely thin bent portion 14 is generated in the sealing portion, or the axial symmetry is extremely disturbed. Doing so is avoided. Therefore, the reliability of sealing can be secured.

However, in the case where a thin and hard glass tube is used as described above, if the above-mentioned reservoir or thin bent portion remarkably occurs, good sealing is not only hindered. Due to the generation of strain due to this, for example, the stress in the cooling step becomes large, and the sealing portion 1
2 or in the vicinity thereof causes cracks, resulting in a defective display device or a reduction in life after the product is manufactured, resulting in a decrease in reliability.

[0018]

DISCLOSURE OF THE INVENTION The present invention uses a flat container, such as the FED, which forms a space having a very small internal thickness as described above, and the inside of the container is evacuated and maintained at a high degree of vacuum. In a flat display device that needs to have a small coefficient of thermal expansion, that is, in a method of manufacturing a flat display device that is exhausted and sealed by a thin glass chip tube made of hard glass,
It is intended to solve the decrease in reliability caused by the sealing portion.

[0019]

According to the present invention, when the sealing portion of the chip tube is heated and melted by electrothermal sealing to seal the sealing portion, the sealing portion is extended along the axial direction of the chip tube. Method.

[0020]

According to the method of the present invention, when the tip tube is sealed, the tip tube is stretched in the axial direction of the tube, so that it is less likely to cause meat accumulation, and a negative pressure of molten or softened glass into the tip tube. It is possible to prevent the pull-in due to the pull-in, thereby avoiding the occurrence of remarkable unevenness in wall thickness and the occurrence of bent portions, and it is possible to reduce the occurrence of distortion in this sealing portion. You can

Therefore, it is possible to achieve reliable sealing in this sealing portion and improve reliability by avoiding the occurrence of a large distortion.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of the embodiment of the manufacturing method of the present invention, an example of a sealing device used for carrying out the manufacturing method of the present invention is shown in FIG.
This will be described with reference to the configuration diagram of FIG.

In the illustrated example, a support base 21 for supporting the flat display device body, that is, the flat container 4 is provided.

The flat container 4 constituting the flat display device by the FED having the structure described with reference to FIGS. 4 to 6 is mounted on the support base 21 by the holder 22 provided on the support base 21. On the other hand, for example, it is held upright in the vertical direction.

On the back panel of the flat container 4, that is, on the outer surface of the first glass panel 1, a chip tube 11 is arranged along the same so as to communicate with the flat space inside the flat container 4.

Further, the support base 21 is provided with an electric heating heater 2
2, the heating means 23 is provided which heats the sealing portion of the chip tube 11 locally in the tube axial direction but heats the sealing portion substantially uniformly over the entire circumference thereof.

The outer end of the tip tube 11 is evacuated by a vacuum pump 24, for example, a rotary pump, which is an exhaust system 25.
Connected to.

In this device, the main body of the flat display device, that is, the flat container 4 supported on the support base 21.
The tip tube 11 attached to the flat tube 4 is provided with both end portions along the tube axis between the end portion 11a on the side of connection with the flat container 4 and the end portion 11b on the side of connection with the exhaust system 25 on the opposite side. It is possible to apply an external force that stretches the tip tube 11 in a direction in which they are separated from each other, that is, in the tube axis direction. For this purpose, for example, the exhaust system 25 of the tip tube 11 is attached to the support base 2
1 along the tube axis direction of the tip tube 11 to the support 21
From the exhaust system 25 or the support base 21 can be moved relative to the exhaust system 25 in the axial direction of the tip tube 11 in the direction away from the exhaust system 25.

In the manufacturing method of the present invention, for example, a flat display device is manufactured using such a device.

Here, the tip tube 11 attached to the flat container 4 is made of, for example, a low thermal expansion coefficient, that is, a hard glass tube having an inner diameter of 7 mm and an outer diameter of 9 mm, that is, a wall thickness of 1 mm.

First, the whole flat container 4 supported on the support 21 is heated by a heating means (not shown) for heating the entire flat container 4 to release gas from each part, so-called degassing, and thereafter, for example, to stop heating. Then, the heating temperature is lowered, and the chip tube 11 is evacuated by the evacuation system 25 to evacuate the container 4, for example, to 2 × 10 ⁻⁶ Pa. Then, the power supply 26 is applied to the electric heater 22 of the heating means 23.
Is turned on to energize, and the sealing portion of the chip tube 11 is locally heated in the axial direction, but is heated over the entire circumference.

In this way, as shown in FIGS. 2A to 2F, the state of change in the transverse sectional view at the sealing portion is such that the cross-sectional shape in the initial state is substantially circular as shown in FIG. 2A. The existing tip tube 11 starts to deform so that the tip tube 1 contracts when the inside of the tip tube 11 is made a negative pressure by exhausting from the softening or melting start portion by softening or melting by heating. As shown in FIG. 2B, the cross section has a flat shape.

This shrinkage deformation is C → D →
It changes from E to F, and the sealing portion is closed. The state of FIG. 2D shows a state in which the exhaust passage is closed at a part of the sealing portion in the pipe axis direction. In the manufacturing method of the present invention, it is shown at the time when this closing occurs or as shown in FIG. 2E. As described above, before and after the central hole of the tip tube 11 is closed almost all over the sealing portion in the tube axis direction, for example, in the apparatus shown in FIG. By moving the tip tube 11 relative to the end portion 1 of the tip tube 11.
Stretch 1a and 11b in a direction away from each other.
This stretched length is, for example, about 5 mm to 10 mm. At this time, the sealed portion is prevented from being pulled out from the heating region of the heating means.

In this way, the chip tube 11 is sealed, but according to the manufacturing method of the present invention, the chip tube 11 is stretched at the time of sealing, so FIGS. 3A and 3B show one longitudinal sectional view and FIG. As shown in the vertical cross-sectional view orthogonal to this cross-section, in the sealing portion 12 of the chip tube 11, the glass wall is sealed inside the chip tube 11 during the sealing.
It is possible to suppress the phenomenon that the bulging portion 15 is pulled toward the connection side with the tip tube, and to make the bulging amount of the bulging portion 15 into the tip tube smaller than that in the case of FIG.
Can be avoided. Therefore, the occurrence of a remarkable thin portion,
Generation of the bent portion 14 is also alleviated.

By the above-mentioned stretching at the time of such sealing, the cross-sectional area of the sealing portion becomes small and it becomes easy to heat it. At this time, if necessary, the amount of electricity supplied to the heater 22 of the heating means 23. Can be reduced to a slightly lower temperature.

After this sealing is performed, the high temperature heating by the heating means is stopped and gradually cooled, and the unnecessary portion at the tip of the chip tube 11 is cut with a file or the like at the sealing portion.

As described above, according to the manufacturing method of the present invention, it is possible to effectively avoid the occurrence of a significant difference in wall thickness, bending or the like in the sealing portion 12 of the chip tube 11.

In the above description, the FED flat display device is mainly described, but the present invention is not limited to the case of obtaining the FED flat display device, and various other flat display devices having the same problem can be used. When it is obtained, the same effect can be obtained.

[0039]

As described above, according to the manufacturing method of the present invention,
Since it is possible to effectively avoid the occurrence of a significant difference in wall thickness, bending, etc., in the sealing portion 12 of the chip tube 11, it is possible to avoid the occurrence of distortion, which allows reliable sealing and yield. It is possible to manufacture a flat display device having high reliability.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a sealing device applied to an example of a manufacturing method of the present invention.

FIG. 2 is a transverse cross-sectional view showing how the cross-section changes in the sealing portion, which is used for explaining an example of the production method of the present invention.

FIG. 3A is a vertical cross-sectional view of an example of a sealing portion of a flat display device according to the manufacturing method of the present invention. B is a vertical cross-sectional view orthogonal to the cross-section of FIG.

FIG. 4 is a schematic perspective view of an example of a flat display device obtained by the manufacturing method of the present invention.

FIG. 5 is a schematic perspective view of a main part of an example of a flat display device obtained by the manufacturing method of the present invention.

FIG. 6 is a schematic enlarged perspective view of a further main part of an example of a flat display device obtained by the manufacturing method of the present invention.

FIG. 7A is a vertical cross-sectional view of an example of a sealing portion of a flat display device according to a conventional manufacturing method. B is a vertical cross-sectional view orthogonal to the cross-section of FIG.

[Explanation of symbols]

 1 1st glass panel 2 2nd glass panel 4 Flat container 11 Chip tube 12 Sealing part

Claims (1)

[Claims] 1. A flat display device characterized in that, when the sealing portion of the chip tube is heated and melted by electrothermal sealing to seal the sealing portion, the sealing portion is extended along the axial direction of the chip tube. Manufacturing method.