JP3177087B2 - Hermetic sealing structure and manufacturing method thereof - Google Patents

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 of manufacturing the same, and more particularly, to a technology for sealing a vacuum tube and a gas-filled tube, and in particular, a technology for sealing a minute volume. The present invention relates to a hermetically 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 which emits electrons in a high electric field has been developed by a fine processing technique used in the field of an integrated circuit or a thin film. Application to a type display or the like is being studied. In particular, the application to a flat display is described in Meyer (MTI) of France Leti (LETI).
ayer et al., according to a study published in the 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)).

FIG. 5 and FIG. 6 are structural views 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 substrate on the side of the phosphor, 12 is a substrate on the side of the electron source, 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. A substrate 11 on the phosphor side on which the transparent electrode 13 and the phosphor 14 are formed, and a substrate 12 on the electron source side constituting a matrix of the emitter electrode 15 and the gate electrode 17 with the insulating layer 16 interposed therebetween. At the intersection A of the matrix of the substrate 12 on the electron source side.
As shown in FIG. 6 which is an enlarged cross-sectional perspective view, a conical minute emitter 18 is formed. Electrons are emitted from the minute emitter 18 by an electric field, the electrons are accelerated by the electric field, collide with the phosphor 14, and display is performed by causing the phosphor 14 to emit light.

FIG. 7 is a 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 vessel is constituted by the phosphor-side substrate 11 and the electron source-side substrate 12 and the sealing portion 21 which are arranged to face each other with the spacer 22 interposed therebetween. A pipe 23 for exhaustion is attached to the substrate 12 on the electron source side, and the vacuum vessel is evacuated using the pipe 23 and then sealed.

[0005]

In a device using a field emission type micro cold cathode, it is essential to maintain an ultra-high vacuum in order to operate stably, and it is preferable to maintain a gas pressure of 10 ^-9 Torr or less. Need to hold. In addition, devices using these field emission type micro cold cathodes have the advantage that they can be much smaller than conventional vacuum tubes. But,
In this case, there is a disadvantage that the internal volume of the container for holding the vacuum is very small, and since the internal volume of the vacuum container is small, a relatively small amount of leak at the same level as the conventional vacuum tube is generated. Even if it occurs, there is a problem that the gas pressure in the vacuum vessel rises considerably and the life of the element is shortened.

The present invention has been made in view of such circumstances, and in hermetic sealing of a flat display, a sealing portion provided between substrates arranged opposite to each other is multiplexed.
A hermetically sealed structure and a manufacturing method thereof, in which a groove is formed in the substrate between the multiple sealed portions to increase the internal volume between the multiple sealed portions and keep the inside of the container under a high vacuum for a long time. It is intended to provide a way.

[0007]

According to the present invention, in order to achieve the above object, (1) two flat substrates are paired in parallel.
With the inner and outer double loops between the substrates.
A double-hermetic seal between the opposing substrates
A space is formed, and gas entering from the outer sealing portion
Volume to lower the gas pressure
(2) In (1), the inner sealing portion and the
Less of the two substrates in the area between the outer sealing part
By providing a groove inside one of the substrates
Between the inner sealing portion and the outer sealing portion.
It has a large volume, and further, (3) (1) or (2), the sealing of the outer and the inner sealing portion
That a getter was formed between the first and second portions, and (4)
(1) A method for manufacturing the hermetically sealed structure according to (2) or (3).
Wherein at least one of said two parallel plates is
Forming an adhesive layer for forming the sealing portion
And an atmosphere similar to the atmosphere in the required hermetic space
Inside, the two substrates are bonded via the bonding layer
And the step of performing

[0008]

According to the present invention, in a device using a field emission type micro cold cathode in which the volume of a vacuum vessel is very small, sealing portions are multiplexed, and a volume is provided between each sealing portion. In this structure, as a first step, gas leaks from the atmosphere and enters the volume between the outer sealing layer of the vacuum container and the inner sealing layer. Further, as a second step, gas leaks into the vacuum vessel through the sealing layer inside the vacuum vessel and enters, and the amount of leakage at this time is such that the sealing layer and the inner sealing layer are outside the vacuum vessel. Is proportional to the pressure difference between the inside and the inside of the vacuum vessel, and the volume between the outer sealing layer and the inner sealing layer of the vacuum vessel is Because it acts as a buffer to keep the pressure low, it is very low compared to the first stage leakage. For this reason, it becomes possible to maintain the inside of the vacuum vessel at an ultra-high vacuum for a longer period of time as compared with the conventional example in which the sealing portion is one place, and the life of the element can be extended.

[0009]

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

[0010] The substrate 1 on the phosphor side opposed to the substrate 1 with the spacer 4 interposed therebetween, the substrate 2 on the electron source side and the sealing portions 3 and 3a between the two substrates, and the sealing portion of the substrate 1 on the phosphor side. A groove 5 for increasing the volume between the sealing portions 3 and 3a is formed in a portion between the sealing portions 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 changed to the inner sealing portion 3 and the outer sealing portion 3a.
And a groove 5 formed inside the substrate 1 on the phosphor side to form a volume between the double sealing portions.

FIG. 2 is a top view of the substrate on the phosphor side in FIG. 1, and reference numerals in the figure are the same as those in FIG. The substrate 1 on the phosphor side is 7059 glass (Corning) having a thickness of 1 mm.
The substrate is 3mm wide and 60mm long outside the display.
Two grooves 5 having a depth of 0.5 mm are formed.
0.1 μm thick ITO 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 structural view of a peripheral portion on the substrate on the side of the phosphor in FIG. 1, and the reference numerals in FIG. 3 are the same as those in FIG. One sealing portion 3 is provided inside the groove 5, and the other sealing portion 3 a is provided outside the groove 5, and the both sealing portions 3, 3 a are in an airtight space on the phosphor-side substrate 1. Are looped around to form After the sealing portions (frit layers) 3 and 3a for performing vacuum sealing are coated with a frit glass paste by screen printing, 1
Drying at 20 ° C. and calcination at 450 ° C. are performed to form a thickness of 120 to 150 μm.

The substrate 2 on the electron source side in FIG. 1 has the same configuration as that of the conventional substrate 12 on the electron source side shown in FIG. 5 and will be described with reference to FIG. 7059 with 1mm thickness
On a glass (corning) substrate 12, a gate electrode 17 and an emitter electrode 15 each having a thickness of 0.4 μm and a width of 0.2 mm made of Mo are wired so as to be orthogonal to each other. About 10,000 emitters
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, respectively, The number of the 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 where a glass ball-shaped spacer having a diameter of 100 μm is scattered are set in a vacuum chamber and evacuated to 10 ⁻⁷ Torr or less. Both substrates are heated to 300 ° C. for degas and held for about 24 hours. After that, put both substrates together,
After heating to 500 ° C. while applying a pressure of about 0.1 N / cm ² and holding for 30 minutes, the temperature is lowered to room temperature at a rate of 3 ° C./min or less to perform sealing. The flat display using the field emission type micro cold cathode manufactured in this way is:
A long-term stable operation was confirmed as compared with the case where the sealing portion was similarly manufactured at one place.

FIG. 4 is a view showing another embodiment of the hermetically sealed structure according to the present invention, and is another sectional view of a flat type display using a field emission type micro cold cathode. In the figure, reference numeral 6 denotes a getter, and other portions having the same functions as those in FIG. 1 are denoted by the same reference numerals. It is composed of a substrate 1 on the phosphor side opposed to the substrate 1 with a spacer 4 interposed therebetween, a substrate 2 on the electron source side and sealing portions 3 and 3a between the two substrates, and sealing portions 3 and 3a of the substrate 1 on the phosphor side. Between the sealing portions 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. The getter 6 forms the frit layers 3 and 3a on the phosphor-side substrate 1 and then forms a metal getter thin film on the surface of the groove 5 by sputtering, and the electron source-side substrate 2 and the phosphor-side substrate After sealing 1, it is formed by re-evaporating and activating by laser heating.

Although the present invention is not limited by the material of the metal getter, in this embodiment, Al (aluminum) obtained by adding 5 wt% of Mg to the material of the metal getter is used.
Was used. Also, the sealing portions 3 and 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 short circuit between the electrode lines due to the getter 6.

In this embodiment, the getter is formed by re-evaporating the metal thin film by laser heating and activating the metal thin film. However, the method of re-evaporation is not limited to laser heating. It may be re-evaporated by heating. 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 display using the field emission type micro-cathode manufactured in this way can confirm a long-term stable operation as compared with the case where the sealing portion is one, similarly to the embodiment shown in FIG. Was.

[0019]

As is apparent from the above description, according to the present invention, in a device using a field emission type micro cold cathode having a very small volume of a vacuum vessel, the sealing portion is multiplexed, By providing a volume between the sealing portions, it is possible to maintain the inside of the vacuum vessel at an ultra-high vacuum for a long period of time, and to provide an element that can operate stably for a long period of time. Further, by increasing the number of sealing portions, the yield is also improved.

[Brief description of the drawings]

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

FIG. 2 is a top view of a substrate on a phosphor side in FIG. 1;

FIG. 3 is a configuration diagram of a peripheral portion on a substrate on a phosphor side in FIG. 1;

FIG. 4 is a view showing another embodiment of the hermetic sealing 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 panel display.

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

[Explanation of symbols]

1: substrate on the phosphor side, 2: substrate on the electron source side, 3, 3a ...
Sealing part, 4 spacer, 5 groove, 6 getter.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01J 29/86 H01J 9/24-9/26

Claims (4)

(57) [Claims] 1. A method in which two flat substrates are opposed in parallel.
Between the substrates, inside and outside double loop
To provide a double hermetic space between the opposing substrates.
An airtightly sealed structure characterized by being formed . 2. The inner sealing portion and the outer sealing portion.
At least one of the two substrates in the portion between
By providing a groove inside one of the substrates,
Increasing the volume between the sealing part and the outer sealing part
The hermetic sealing structure according to claim 1, wherein: 3. The inner sealing portion and the outer sealing portion.
3. The hermetically sealed structure according to claim 1 , wherein a getter is formed between the airtight seal structure and the airtight seal structure. 4. An airtightly sealed structure according to claim 1, wherein
A method of manufacturing, wherein the two flat substrates are reduced in number.
And forming an adhesive layer for forming the sealing portion on one side.
Process and the atmosphere in the required hermetic space
In such an atmosphere, the two substrates are
Method for manufacturing a hermetically sealed structure you; and a step of bonding through.