JPH07249388A - Gastight seal structure and manufacture thereof - Google Patents

Abstract

PURPOSE:To maintain a container in high vacuum for a long time by installing volume between first and second gastight containers, and reducing the pressure of a gas penetrating from a sealed part of the second gastight container. CONSTITUTION:A board 1 of a first gastight container on a phosphor side and a board 2 of a second gastight container on an electron gun side arranged so as to face through spacers 4, and sealed parts 3, 3a between the boards 1, 2 are formed. A groove 5 for enlarging volume is formed in the sealed parts 3, 3a of the board 1. Double sealed part of the inside sealed part 3 and the outside sealed part 3a is formed so as to have the groove 5 on the inside of the board 1 and volume is formed between the double sealed parts 3, 3a. Air leaks from the outside through the sealed part 3a on the outside of the second vacuum container, and gas leaks through the sealed part 3 on the inside of the second vacuum container. Since the pressure of gas penetrated into the volume part is reduced, the pressure difference between the volume part and the vacuum container is made small, and leakage amount is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hermetically sealed structure and a method for manufacturing the same, and more particularly, to a vacuum tube and a gas sealing tube sealing technology, in particular, a sealing technology using a micro volume. The present invention relates to a tightly sealed structure and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, a field emission type micro electron source that emits electrons in a high electric field has been developed by a microfabrication technique used in the field of integrated circuits or thin films. Application to portable displays is under consideration. Especially, the application to the flat panel display is performed by Meyer (M) of France Leti (LETI).
ayer) et al., and is known by the research report published in International Conference on Vacuum Microelectronics 91 (IVMC91). (`` RECENT DEVELOPMENTON “MICROTIP
S "DISPLAY AT LETI" (R. Meyer, Technical Digest of
IVMC 91, Nagahama 1991, pp.6-9)).

5 and 6 are configuration diagrams of a conventional flat display, FIG. 5 is a perspective view, and FIG. 6 is an enlarged sectional perspective view. In the figure, 11 is a phosphor side substrate, 12 is an electron source side substrate, 13 is a transparent electrode, 14 is a phosphor, 15 is an emitter electrode, 16 is an insulating layer, 17 is a gate electrode, and 18 is a minute emitter. The phosphor-side substrate 11 on which the transparent electrode 13 and the phosphor 14 are formed and the electron-source-side substrate 12 forming a matrix of the emitter electrode 15 and the gate electrode 17 with the insulating layer 16 in between are arranged to face each other. The structure is such that the intersection point A of the matrix of the substrate 12 on the electron source side is
As shown in FIG. 6 which is an enlarged cross-sectional perspective view of the same, a minute emitter 18 having a conical shape is formed. An electron is emitted from the minute emitter 18 by an electric field, the electron is accelerated by the electric field, collides with the phosphor 14, and the phosphor 14 is caused to emit light to perform display.

FIG. 7 is a cross-sectional view of a conventional flat display, in which 21 is a sealing portion, 22 is a spacer, 23 is a pipe, and other portions having the same functions as those in FIG. It is attached. A vacuum container is constituted by the substrate 11 on the phosphor side, which is arranged to face each other via the spacer 22, the substrate 12 on the electron source side, and the sealing portion 21. A pipe 23 for exhausting gas is attached to the substrate 12 on the electron source side, and the vacuum container is exhausted using the pipe 23 and then sealed.

[0005]

An element using a field emission type micro cold cathode is required to maintain an ultrahigh vacuum in order to operate stably, and the gas pressure is preferably 10 ^-9 Torr or less. Need to hold. Further, the element using these field emission type micro cold cathodes has an advantage that it can be made much smaller than the conventional vacuum tube. But,
In this case, there is a demerit that the inner volume of the container for holding the vacuum is very small, and due to the small inner volume of this vacuum container, a relatively small amount of leak at the same level as a conventional vacuum tube is generated. Even if it occurs, there is a problem that the gas pressure in the vacuum container rises considerably and the life of the element is shortened.

The present invention has been made in view of the above circumstances, and in the hermetic sealing of a flat panel display, multiple sealing parts are provided between substrates arranged to face each other,
By forming a groove in the substrate between the multiple sealed portions, the internal volume between the multiple sealed portions is increased, and the inside of the container is kept in a high vacuum for a long time. It is intended to provide a way.

[0007]

In order to achieve the above object, the present invention provides: (1) an airtight container and a first airtight container provided with a sealing means for keeping airtightness, A second airtight container is provided so as to surround the one airtight container and a sealing means for keeping airtightness is provided, and between the first airtight container and the second airtight container, a second airtight container A volume is provided to reduce the gas pressure due to the gas that has entered from the sealed portion, and (2) the first hermetic container and the second hermetic container are formed of the same container. Further, (3) in the above (2), two flat plate-shaped substrates are arranged to face each other, a multiple sealing layer is provided between the substrates, and a first sealing layer and a second sealing layer are provided. To form a groove on the inside of at least one of the two substrates in the part between the stop layer and A volume is formed between the first sealing layer and the second sealing layer, and further, (4) in the above (1), the first hermetic container and the second hermetic container. Forming a getter between and, or (5)
Two flat plate-shaped substrates are arranged to face each other, multiple sealing layers are provided between the substrates, and the two substrates in the portion between the first sealing layer and the second sealing layer are provided. A method for manufacturing an airtight sealing structure, which comprises forming a volume between a first sealing layer and a second sealing layer by forming a groove inside at least one of the substrates. Then, in at least one of the two parallel flat plates, at least two layers for sealing are formed to form an adhesive layer, and the two parallel flat plates are placed in an atmosphere similar to the required atmosphere in the airtight container. And a step of adhering via the adhesive layer.

[0008]

According to the present invention, in the element using the field emission type micro cold cathode having a very small volume of the vacuum container, the sealing portions are multiplexed and the volumes are provided between the respective sealing portions. In this structure, as the first step, gas leaks from the atmosphere and invades into a volume portion between the inner sealing layer and the outer sealing layer of the vacuum container. Further, as a second step, gas leaks into the vacuum container through the sealing layer inside the vacuum container and invades, but at this time, the amount of leakage is the sealing layer on the outside of the vacuum container and the sealing layer on the inside. Is proportional to the pressure difference between the volume of the vacuum vessel and the inside of the vacuum vessel, and the volume of the volume between the outer sealing layer and the inner sealing layer of the vacuum vessel is the It acts as a buffer to keep the pressure low, so it is very low compared to the first stage leak rate. For this reason, it becomes possible to maintain the inside of the vacuum container at an ultrahigh vacuum for a long period of time, as compared with the conventional example in which the sealing portion is one, and the life of the element can be extended.

[0009]

Embodiments will be described below with reference to the drawings. FIG. 1 is a configuration diagram for explaining an embodiment of a hermetically sealed structure according to the present invention, and is a cross-sectional view of a flat panel display using a field emission type micro cold cathode. In the figure, 1 is a phosphor side substrate, 2 is an electron source side substrate, 3 and 3a are sealing parts, 4 is a spacer, and 5 is a groove.

The phosphor-side substrate 1 and the electron-source-side substrate 2 and the sealing portions 3 and 3a between the two substrates, which are arranged to face each other with a spacer 4 interposed therebetween, and the phosphor-side substrate 1 is sealed. A groove 5 for increasing the volume between the sealing portions 3 and 3a is formed in the portion between 3 and 3a. That is, the sealing portion between the substrate 1 on the phosphor side and the substrate 2 on the electron emission source side is the inner sealing portion 3 and the outer sealing portion 3a.
And a groove 5 is formed inside the substrate 1 on the phosphor side, thereby forming a volume between the double sealed portions.

FIG. 2 is a top view of the substrate on the phosphor side in FIG. 1, and the reference numerals in the figure are the same as those in FIG. The substrate 1 on the phosphor side is 7059 glass with a thickness of 1 mm (Corning)
It is a substrate and has a width of 3 mm and a length of 60 mm on the outside of the display.
Two grooves 5 each having a depth of 0.5 mm are formed.
ITO having a thickness of 0.1 μm as a transparent electrode on the substrate 1
(Indium tin oxide) is formed by sputtering, and ZnO having a thickness of 1 μm is formed as a fluorescent layer on the transparent electrode:
Zn is formed by electron beam evaporation.

FIG. 3 is a configuration diagram of the peripheral portion on the phosphor side substrate in FIG. 1, and the reference numerals in the figure are the same as those in FIG. One sealing portion 3 is provided inside the groove 5, and the other sealing portion 3a is provided outside the groove 5, and both sealing portions 3 and 3a are airtight spaces on the substrate 1 on the phosphor side. Are looped around to form a. After applying the frit glass paste by screen printing to the sealing portions (frit layers) 3 and 3a for vacuum sealing, 1
By drying at 20 ° C. and calcination at 450 ° C., a thickness of 120 to 150 μm is formed.

Since the substrate 2 on the electron source side in FIG. 1 has the same structure as the substrate 12 on the electron source side shown in FIG. 5 of the conventional example, it will be described below with reference to FIG. 7059 with a thickness of 1 mm
A gate electrode 17 and an emitter electrode 15 each made of Mo and having a thickness of 0.4 μm and a width of 0.2 mm are wired on the glass (Corning) substrate 12 so as to be orthogonal to each other, and the intersections of the gate electrodes 17 and the emitter electrodes 15 are minutely made of Mo. The emitter is about 10000
Individually formed. The size of the matrix electron source formed on the substrate 2 on the electron source side is 60.8 mm × 83.6 mm, the pitch between the gate electrode 17 and the emitter electrode 15 is 0.38 mm, and The number of emitter electrodes 15 is 120 and 160, respectively.

Next, the substrate 2 on the electron source side and the substrate 1 on the phosphor side in a state in which glass ball-shaped spacers having a diameter of 100 μm are scattered are set in a vacuum chamber, and after evacuating to 10 ⁻⁷ Torr or less, Both substrates are heated to 300 ° C. for degassing and kept for about 24 hours. After that, stack both substrates,
It is heated to 500 ° C. while applying a pressure of about 0.1 N / cm ² and held for 30 minutes, and then the temperature is lowered to room temperature at a rate of 3 ° C./min or less to perform sealing. The flat-panel display using the field emission type micro cold cathode thus manufactured is
It was confirmed that a stable operation for a long period of time was confirmed as compared with the case where the sealing part produced in the same manner was one.

FIG. 4 is a view showing another embodiment of the hermetically sealed structure according to the present invention, which is another cross-sectional view of a flat panel display using a field emission type micro cold cathode. In the figure, reference numeral 6 is a getter, and other parts having the same functions as those in FIG. 1 are designated by the same reference numerals. The phosphor-side substrate 1 and the electron-source-side substrate 2 and the sealing portions 3 and 3a between the two substrates, which are arranged to face each other with the spacer 4 interposed therebetween, and the phosphor-side substrate 1 has the sealing portions 3 and 3a. The sealing portion 3, 3a
A groove 5 is formed to increase the volume between them.
Further, a getter 6 is formed on the surface of the groove 5.

The difference from the embodiment shown in FIG. 1 is that a getter 6 is formed on the surface of the groove 5. In the getter 6, after forming the frit layers 3 and 3a on the substrate 1 on the phosphor side, a thin film of a metal getter is formed on the surface of the groove 5 by sputtering, and the substrate 2 on the electron source side and the substrate on the phosphor side are formed. 1 is sealed and then re-evaporated by laser heating to be activated and formed.

Although the present invention is not limited by the material of the metal getter, in the present embodiment, Al (aluminum) obtained by adding 5 wt% of Mg to the material of the metal getter is used.
Was used. In addition, the sealing portions 3, 3a of the substrate 2 on the electron source side
An insulating layer of SiO ₂ is formed on the surface of the portion between the electrodes to prevent a short circuit between the electrode lines due to the getter 6.

In the present embodiment, the metal thin film is re-evaporated by laser heating and activated to form the getter. However, the method of re-evaporating is not limited to laser heating, and high frequency heating or resistance is used. It may be re-evaporated by heating. Further, a non-evaporable getter material made of a Zr alloy such as Zr-Al or Zr-V-Fe may be used without re-evaporation. The flat panel display using the field emission type micro cold cathode thus manufactured can be confirmed to have stable operation for a long period of time as compared with the case where the sealing portion is one, as in the embodiment shown in FIG. It was

[0019]

As is apparent from the above description, according to the present invention, in an element using a field emission type micro cold cathode having a very small volume of the vacuum container, the sealing portion is multiplexed and By providing the volume between the sealed portions, it is possible to maintain the inside of the vacuum container at an ultrahigh vacuum for a long period of time, and it is possible to provide an element that can stably operate for a long period of time. Moreover, the yield is improved by multiplexing the sealing portions.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining an embodiment of a hermetically sealed structure according to the present invention.

FIG. 2 is a top view of a phosphor-side substrate in FIG.

FIG. 3 is a configuration diagram of a peripheral portion on a phosphor side substrate in FIG.

FIG. 4 is a view showing another embodiment of the hermetically sealed structure according to the present invention.

FIG. 5 is a perspective view of a conventional flat display.

FIG. 6 is an enlarged sectional perspective view of a conventional flat display.

FIG. 7 is a cross-sectional view of a conventional flat display.

[Explanation of symbols]

1 ... Phosphor side substrate, 2 ... Electron source side substrate, 3, 3a ...
Sealing part, 4 ... Spacer, 5 ... Groove, 6 ... Getter.

Claims (5)

[Claims] 1. An airtight container and a first airtight container provided with a sealing means for keeping the airtightness, the first airtight container being surrounded by the second airtight container so as to keep the airtightness. A sealing means is provided, and a volume is provided between the first airtight container and the second airtight container to reduce the gas pressure due to the gas that has entered from the sealed portion of the second airtight container. A hermetically sealed structure characterized by the above. 2. The hermetically sealed structure according to claim 1, wherein the first hermetic container and the second hermetic container are formed of the same container. 3. Two flat plate-shaped substrates are arranged to face each other, multiple sealing layers are provided between the substrates, and a portion between the first sealing layer and the second sealing layer is provided. It is characterized in that a volume is formed between the first sealing layer and the second sealing layer by forming a groove inside at least one of the two substrates. The hermetically sealed structure according to claim 2. 4. The hermetically sealed structure according to claim 1, wherein a getter is formed between the first hermetic container and the second hermetic container. 5. Two flat plate-shaped substrates are arranged so as to face each other, a multiple sealing layer is provided between the substrates, and a portion between the first sealing layer and the second sealing layer is provided. An airtight sealing structure in which a volume is formed between the first sealing layer and the second sealing layer by forming a groove inside at least one of the two substrates. And a step of forming an adhesive layer in at least one double layer for sealing on at least one of the two parallel flat plates, and in an atmosphere similar to the atmosphere in the required airtight container, And a step of adhering a plurality of parallel flat plates via the adhesive layer, the method for producing an airtightly sealed structure.