JP2005331673A - Method for manufacturing image display apparatus and sealing material filling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an image display apparatus and a sealing material filling device, by which formation of an oxide film on the surface of a metal sealing material is prevented and wettability of the metal sealing material on the sealing face is improved, even though the metal sealing material melted in air is made to fill, and complete sealing can be performed. <P>SOLUTION: The method for manufacturing an image display apparatus having a back substrate, an envelope having a front substrate 11 disposed to oppose the back substrate, and a plurality of display elements laid inside the envelope includes steps of bringing a nozzle end face 55c into contact with the sealing face between the back substrate and the front substrate and filling the sealing face with molten indium (metal sealing material), in an atmosphere with reduced oxygen around the nozzle end face; and heating and melting the metal sealing material, after filling the sealing face with the metal sealing material, and directly or indirectly sealing the back substrate and the front substrate on the sealing face. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a manufacturing method and a sealing material filling apparatus for manufacturing an image display device having substrates disposed opposite to each other and a plurality of display elements provided between the substrates.

In recent years, as a next-generation lightweight and thin flat display device, development of a display device in which a large number of electron-emitting devices (hereinafter referred to as emitters) are arranged and opposed to a phosphor screen has been advanced. As the emitter, a field emission type or surface conduction type element is assumed. In general, a display device using a field emission electron emitter as an emitter is a field emission display (hereinafter referred to as FED), and a display device using a surface conduction electron emitter as an emitter is a surface conduction electron emission. It is called a display (hereinafter referred to as SED).
The FED has a front substrate and a rear substrate that are arranged to face each other with a predetermined gap, and these substrates are connected to each other through a rectangular frame-shaped side wall to form a vacuum envelope. It is composed. A phosphor screen is formed on the inner surface of the front substrate, and a plurality of electron-emitting devices are provided on the inner surface of the rear substrate as electron emission sources that excite the phosphor to emit light. Further, in order to support an atmospheric pressure load applied to the back substrate and the front substrate, a plurality of support members are disposed between these substrates.

The potential on the back substrate side is approximately 0 V, and the anode voltage Va is applied to the phosphor screen. The red, green, and blue phosphors that make up the phosphor screen are irradiated with the electron beams emitted from the electron-emitting devices, and the phosphors emit light to display an image. In such an FED, the gap between the front substrate and the rear substrate can be set to several millimeters or less, which is lighter than a cathode ray tube (CRT) currently used as a display of a television or a computer. Thinning can be achieved.
The present applicant has previously filed [Patent Document 1] a related technique of the above-described manufacturing method of the image display device and the sealing material filling device.
As a manufacturing method of the image display device described here, a step of filling a molten metal sealing material while applying ultrasonic waves to a sealing surface between a back substrate and a front substrate, and a metal sealing material After the filling, the method includes a step of heating the metal sealing material in a vacuum atmosphere to melt and sealing the back substrate and the front substrate directly or indirectly on the sealing surface.
Furthermore, as a sealing material filling device for filling the sealing surface with a metal sealing material, a support base for positioning and supporting an object to be sealed having a sealing surface, and a storage unit for storing a molten metal sealing material, A nozzle that fills the sealing surface with the molten metal sealing material sent from the reservoir, and an ultrasonic generator that applies ultrasonic waves to the molten metal sealing material that fills the sealing surface from the nozzle. A head and a head moving mechanism that moves the filling head relative to the sealing surface are provided.
JP 2000-377816 A

By the way, since the process of supplying the molten metal sealing material from the nozzle and filling the sealing surface is performed in the atmosphere, the molten metal sealing material surface immediately after filling is cooled and solidified and oxidized, and the surface As a result, an extremely thin oxide film is formed. In the technique of the above [Patent Document 1], by performing a baking process for heating the vacuum envelope to about 300 ° C., the surface adsorbed gas inside the envelope is released and the envelope is passed through the exhaust pipe. The chamber is evacuated and sealed.
That is, by performing sufficient baking treatment, the oxide film is eliminated and the adverse effect on the sealing is suppressed, but a part of the oxide film still remains. Therefore, the process of sealing the back substrate and the front substrate after filling the sealing surface with the metal sealing material directly or indirectly with the sealing surface is not always performed completely, and the part is not sealed. There is a slight probability that it will remain and leak.

  The present invention has been made in view of the above points. The object of the present invention is to suppress the formation of an oxide film on the surface of the metal sealing material in spite of filling the metal sealing material melted in the atmosphere. Thus, an object of the present invention is to provide an image display device manufacturing method and a sealing material filling device which can improve the wettability of the metal sealing material to the sealing surface and enable complete sealing.

In order to achieve the above object, a method of manufacturing an image display device according to an aspect of the present invention includes a back substrate, an envelope having a front substrate disposed opposite to the back substrate, and a plurality of devices provided in the envelope. A display element,
A process of filling the sealing surface with a molten metal sealing material, with the nozzle tip surface applied to the sealing surface between the back substrate and the front substrate, with the nozzle tip surface and its surroundings in an atmosphere with reduced oxygen, A step of filling the sealing surface with a metal sealing material and then heating and melting the metal sealing material to seal the back substrate and the front substrate directly or indirectly on the sealing surface.

According to another aspect of the present invention, there is provided a method for manufacturing an image display device, comprising a rear substrate, a front substrate disposed opposite to the rear substrate, and a peripheral portion of the front substrate and a peripheral portion of the rear substrate. An envelope having a side wall sealed to a front substrate and a back substrate, and a plurality of pixel display elements provided in the envelope, and a sealing surface and a back surface between the front substrate and the side wall At least one of the sealing surfaces between the substrate and the side wall is sealed with a metal sealing material layer,
A process of filling the sealing surface with a molten metal sealing material with the nozzle tip surface and the periphery of the nozzle placed on the sealing surface between the back substrate and the front substrate and the nozzle tip surface and its periphery as a stable gas atmosphere, and a sealing surface And a step of heating the metal sealing material to melt and sealing the back substrate, the front substrate, and the side wall with the sealing surface.

Further, a low melting point metal material is used for the metal sealing material.
Furthermore, the low-melting-point metal material is a simple substance of In, Bi, Sn, or Ga or an alloy containing at least one.

A sealing material filling apparatus according to an aspect of the present invention is an apparatus for filling a sealing surface with a metal sealing material in the manufacture of an image display device, and a support base for positioning and supporting an object to be sealed having the sealing surface; A storage part for storing the molten metal sealing material, a nozzle for filling the sealing surface with the molten metal sealing material sent from the storage part, and a stable gas by supplying a stable gas to and around the tip surface of the nozzle And a filling head having gas supply means for forming an atmosphere.
Further, the gas supply means includes a chamber containing at least a nozzle therein and filled with a stable gas supplied from a gas supply source, and a gas outlet is provided at a portion facing the nozzle tip surface and the periphery thereof. Opened.
Further, the gas supply means is a blowing tube that guides the stable gas from the gas supply source and blows the stable gas toward the tip surface of the nozzle and the periphery thereof.
Further, the stable gas supplied from the gas supply source to the gas supply means is an inert gas such as nitrogen (N2) gas or argon (Al) gas containing a predetermined amount of oxygen.

According to the present invention, by directly or indirectly sealing the front substrate and the rear substrate using the metal sealing material layer, the electron-emitting device provided on the rear substrate is thermally damaged. Sealing can be done at low temperature.
When supplying molten metal sealing material from the nozzle tip surface and filling the sealing surface in the atmosphere, the nozzle tip surface and its surroundings should be in an atmosphere with reduced oxygen (or inert gas atmosphere). Suppresses the formation of an oxide film on the surface of the filled metal sealing material, improves the wettability of the sealing surface of the metal sealing material, and improves the reliability by ensuring the sealing performance of the sealing Can be planned.

  According to the present invention, in order to manufacture an image display device having high airtightness and sealing strength, the formation of an oxide film in the metal sealing material when the sealing material is filled with the metal sealing material is suppressed. There is an effect that the improvement of the wettability with respect to the sealing surface of the metal sealing material and the improvement of the reliability can be obtained by securing the sealing property of the sealing.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, an FED will be described as an example of an image display device manufactured by the manufacturing method according to the present embodiment.
As shown in FIG. 1 and FIG. 2, this FED includes a front substrate 11 and a rear substrate 12 each made of rectangular glass as insulating substrates, and these substrates have a gap of about 1.5 to 3.0 mm. It is placed facing each other. The front substrate 11 and the back substrate 12 constitute a flat rectangular vacuum envelope 10 whose peripheral portions are sealed with each other via a rectangular frame-shaped side wall 18 made of glass and the inside is maintained in a vacuum state. ing.

A plurality of support members 14 are provided in the vacuum envelope 10 in order to support an atmospheric pressure load applied to the rear substrate 12 and the front substrate 11. These support members 14 extend in a direction parallel to the long side of the vacuum envelope 10 and are arranged at a predetermined interval along a direction parallel to the short side. The shape of the support member 14 is not particularly limited to this, and a columnar support member may be used.
As shown in FIG. 3, a phosphor screen 16 is formed on the inner surface of the front substrate 11. The phosphor screen 16 is formed of phosphor layers R, G, and B that emit light in three colors of red, green, and blue and a matrix-like black light absorbing portion 20. The above-described support member 14 is placed so as to be hidden behind the black light absorbing portion. On the phosphor screen 16, an aluminum layer (not shown) is deposited as a metal back.

As shown in FIG. 2, on the inner surface of the back substrate 12, a large number of field emission electron emission elements 22 each emitting an electron beam are provided as electron emission sources for exciting the phosphor layers R, G, B. It has been. These electron-emitting devices 22 are arranged in a plurality of columns and a plurality of rows corresponding to each pixel, and function as display devices.
More specifically, a conductive cathode layer 24 is formed on the inner surface of the back substrate 12, and a silicon dioxide film 26 having a large number of cavities 25 is formed on the conductive cathode layer. A gate electrode 28 made of molybdenum, niobium or the like is formed on the silicon dioxide film 26. A cone-shaped electron-emitting device 22 made of molybdenum or the like is provided in each cavity 25 on the inner surface of the back substrate 12. In addition, on the rear substrate 12, a matrix-like wiring (not shown) connected to the electron-emitting device 22 is formed.

In the FED configured as described above, a video signal is input to the electron-emitting device 22 and the gate electrode 28 formed in a simple matrix system. When the electron-emitting device 22 is used as a reference, a gate voltage of +100 V is applied when the luminance is highest. Further, +10 kV is applied to the phosphor screen 16. The magnitude of the electron beam emitted from the electron-emitting device 22 is modulated by the voltage of the gate electrode 28, and this electron beam excites the phosphor layer of the phosphor screen 16 to emit light, thereby displaying an image. .
Thus, since a high voltage is applied to the phosphor screen 16, a high strain point glass is used as the plate glass for the front substrate 11, the back substrate 12, the side wall 18, and the support member 14. Further, as described later, the back substrate 12 and the side wall 18 are sealed with a low melting point glass 30 such as frit glass, and the front substrate 11 and the side wall 18 are formed on the sealing surface. The base layer 31 and the indium layer 32 formed on the base layer are sealed by a sealing layer 33 that is fused.

Next, a method for manufacturing the FED configured as described above will be described in detail.
First, the phosphor screen 16 is formed on the plate glass to be the front substrate 11. In this method, a plate glass having the same size as the front substrate 11 is prepared, and a phosphor layer stripe pattern is formed on the plate glass by a plotter machine. The plate glass on which the phosphor stripe pattern is formed and the plate glass for the front substrate are placed on a positioning jig and set on an exposure table, whereby the phosphor screen 16 is generated by exposure and development.
Subsequently, the electron-emitting device 22 is formed on the glass plate for the rear substrate. In this case, a matrix-like conductive cathode layer is formed on the plate glass, and an insulating film of a silicon dioxide film is formed on the conductive cathode layer by, for example, a thermal oxidation method, a CVD method, or a sputtering method.

After that, a metal film for forming a gate electrode such as molybdenum or niobium is formed on the insulating film by, for example, sputtering or electron beam evaporation. Next, a resist pattern having a shape corresponding to the gate electrode to be formed is formed on the metal film by lithography. Using this resist pattern as a mask, the metal film is etched by wet etching or dry etching to form the gate electrode 28.
Next, the cavity 25 is formed by etching the insulating film by wet etching or dry etching using the resist pattern and the gate electrode as a mask. Then, after removing the resist pattern, a peeling layer made of, for example, aluminum or nickel is formed on the gate electrode 28 by performing electron beam evaporation from a direction inclined by a predetermined angle with respect to the back substrate surface.

Thereafter, for example, molybdenum is vapor-deposited as a cathode forming material by an electron beam vapor deposition method from a direction perpendicular to the back substrate surface. As a result, the electron-emitting device 22 is formed inside each cavity 25. Subsequently, the release layer is removed together with the metal film formed thereon by a lift-off method.
A gap between the peripheral edge of the back substrate 12 on which the electron-emitting devices 22 are formed and the side wall 18 having a rectangular frame shape is sealed with a low melting point glass 30 in the atmosphere. At the same time, the plurality of support members 14 are sealed with the low melting point glass 30 on the back substrate 12 in the atmosphere.
Then, the back substrate 12 and the front substrate 11 are sealed to each other through the side wall 18. In this case, as shown in FIGS. 4A and 4B, first, on the upper surface of the side wall 18 serving as a sealing surface in the rear substrate 12 and the inner peripheral edge of the front substrate 11, respectively, for example, a lower layer made of silver paste. The formation 31 is formed by applying a predetermined width over the entire circumference. Note that the entire area of the rear substrate 12 is formed to be slightly larger than the entire area of the front substrate 11, and the position of the base layer 31 with respect to the front substrate 11 and the rear substrate 12 is the same as each other. The distance from the edge to the edge of the foundation layer 31 is set to be larger than the distance from the edge of the front substrate 11 to the edge of the foundation layer.

Subsequently, indium (In) as a metal sealing material is applied on each base layer 31 as will be described later, and an indium layer 32 continuously extending over the entire circumference of the base layer 31 is formed. The indium layer 32 is formed to have a width narrower than that of the base layer 31, and the both side edges of the indium layer 32 are applied with a predetermined gap from both side edges of the base layer 31. For example, when the side wall 18 has a width of 9 mm, the base layer 31 has a width of 8 mm and the indium layer 32 has a width of about 6 mm.
As the metal sealing material, it is desirable to use a low-melting-point metal material having a melting point of about 350 ° C. or less and excellent adhesion and bonding properties. Indium used in this embodiment has not only a low melting point of 156.7 ° C., but also has excellent characteristics such as low vapor pressure, soft and strong against impact, and does not become brittle even at low temperatures. Moreover, since it can be directly bonded to glass depending on conditions, it is a material suitable for the purpose of the present invention.

As the low melting point metal material, not only a simple substance of In as a main component but also a simple substance of Bi, Sn, or Ga or an alloy containing at least one of them can be used. For example, in an eutectic alloy of In97% -Ag3%, the melting point is further lowered to 141 ° C., and the mechanical strength can be increased.
In the above description, the expression “melting point” is used. However, in the case of an alloy composed of two or more metals, the melting point may not be fixed. Generally in such cases, the liquidus temperature and the solidus temperature are defined. The former is a temperature at which a part of the alloy starts to solidify when the temperature is lowered from the liquid state, and the latter is a temperature at which all of the alloy is solidified. In this embodiment, for convenience of explanation, the expression melting point is used even in such a case, and the solidus temperature is called the melting point.

On the other hand, the base layer 31 described above uses a material having good wettability and airtightness with respect to the metal sealing material, that is, a material having high affinity with the metal sealing material. In addition to the silver paste described above, a metal paste such as gold, aluminum, nickel, cobalt, or copper can be used. In addition to the metal paste, a metal plating layer such as silver, gold, aluminum, nickel, cobalt, or copper, a vapor deposition film, or a glass material layer can be used as the base layer 31.
The filling of indium on the underlayer 31 formed on the sealing surface, that is, the application of indium is performed using the following sealing material filling apparatus.
As shown in FIG. 5, the sealing material filling apparatus includes a support base 40 having a flat mounting surface 40a. On the mounting surface, a flat rectangular plate-shaped hot plate 42 and the hot plate There are provided a positioning mechanism 44 for positioning an object to be sealed, a filling head 46 for filling a sealing material on the object to be sealed, and a head moving mechanism 48 for moving the filling head relative to the object to be sealed. ing.

On the hot plate 42, the back substrate 12 or the front substrate 11 to which the side wall 18 is sealed is placed as an object to be sealed. The hot plate 42 also functions as a heating means for heating the mounted article to be sealed. The positioning mechanism 44 contacts, for example, three fixed positioning claws 50 that abut each of two orthogonal sides of the front substrate 11 placed on the hot plate 42 and the other two sides of the front substrate 11 for positioning. Two presser claws 52 that elastically press the front substrate 11 toward the claws 50 are provided.
As shown in FIGS. 5 and 6A, the filling head 46 includes a storage portion 54 that stores molten indium, and a nozzle that fills the sealing surface of the front substrate 11 with molten indium sent from the storage portion. 55. A heater portion 60 for heating the nozzle is attached to the peripheral surface of the nozzle 55. The nozzle 55 is connected to an ultrasonic vibration element U that functions as an ultrasonic wave generation unit via a metal rod 56. When this ultrasonic vibration element U is activated and vibrates ultrasonically, ultrasonic vibration is transmitted to the nozzle 55 via the metal rod 56, and the nozzle end portion performs vertical vibration along the central axis.

Further, the entire circumference of the nozzle 55 including the storage portion 54 and the heater portion 60 constituting the filling head 46 is surrounded by a chamber 59 having a sealed structure. One side of the chamber 59 is connected to a gas supply source (not shown), and a supply pipe p is connected to guide an inert gas, which is a stable gas, from the gas supply source into the chamber.
The chamber 59 is provided in a state where the lower end surface thereof is higher than the tip of the nozzle 55 by a predetermined amount, the tip of the nozzle 55 is inserted into the lower end surface of the chamber 59, and the blowout port that opens with a predetermined gap from the peripheral surface of the nozzle tip 59a is integrally projected. The inert gas, which is a stable gas, is a predetermined amount, for example, about 95% nitrogen (N2) gas or argon (Al) gas containing about 5% oxygen. It is disadvantageous to use.

As shown in FIG. 5, the head moving mechanism 48 is configured such that the filling head 46 is perpendicular to the placement surface 40 a of the support base 40, that is, Z is perpendicular to the front substrate 11 placed on the hot plate 42. A Z-axis drive robot 62 supported so as to be movable up and down along the axial direction, and a Y-axis supported so that the Z-axis drive robot 62 can be driven back and forth along the Y-axis direction parallel to the short side of the front substrate 11. And an axis drive robot 64. Further, the Y-axis drive robot 64 is supported by an X-axis drive robot 66 and an auxiliary rail 67 fixed on the placement surface 40a so as to be reciprocally driven along the X-axis direction parallel to the long side of the front substrate 11. Has been.
When indium is applied using the above-described sealing material filling apparatus, as shown in FIG. 5, the front substrate 11 is placed on the hot plate 42 with the sealing surface facing up, and the positioning mechanism 44 puts the indium in a predetermined position. Position it. Subsequently, as shown in FIG. 6B, after the filling head 46 in which the molten indium is stored in the storage portion 54 is set at a desired filling start position, the head moving mechanism 48 is used to seal the front substrate 11. The filling head 46 is moved at a predetermined speed along the surface, here, the base layer 31 formed on the front substrate 11.

Then, while moving the filling head 46, the molten indium is continuously filled from the nozzle 55 onto the foundation layer 31, and the indium layer 32 extending continuously along the foundation layer 31 is formed over the entire circumference. At the same time, the ultrasonic vibration element U is operated to ultrasonically vibrate the nozzle 55 and fill the underlying layer 31 while applying ultrasonic waves to the molten indium. Accordingly, ultrasonic vibration is generated in the nozzle 55c in a direction perpendicular to the surface of the base layer 31 that is the sealing surface of the front substrate 11. The frequency of the ultrasonic wave is set to 30 to 40 kHz, for example.
Here, the nozzle 55 will be described in detail. The nozzle 55 is provided with the storage portion 54 at the upper portion of the base end portion 55 a, and a metal rod 56 is connected to the upper end surface of the base end portion 55 a that penetrates the storage portion 54, and the upper end of the metal rod 56 is super An ultrasonic vibration element U that functions as a sound wave generator is attached. On the other hand, a nozzle tip 55b formed in a square column shape, for example, is detachably attached to the lower side from the nozzle base end 55a. The tip surface 55c of the nozzle tip 55b is formed as will be described later.

As shown in FIGS. 7A and 7B, a supply hole 57 is provided along the central axis of the nozzle 55. The supply hole 57 opens from the end surface of the base end portion 55a to the tip end surface 55c and guides indium melted from the storage portion 54 connected to the base end portion 55a, and the indium is supplied from the nozzle tip end surface 55c. It has come to be. Since the nozzle tip 55b is formed in a quadrangular prism shape, the cross-sectional shape of the tip is rectangular, and the tip surface 55c is also square. The tip surface 55c of the nozzle 55 is provided with a step portion D cut into a rectangular cross section along the periphery. By providing the step portion D on the nozzle tip surface 55c, the tip of the nozzle 55 is tapered.
As described above, since the supply pipe p extending from the gas supply source is connected to the chamber 59, the chamber 59 is filled with the inert gas, and the outlet 59a which is the only gap is provided. It is designed to be blown out and guided through a gap with the peripheral surface of the nozzle tip 55b. Since the blowout port 59a is open to the nozzle tip surface 55c and its periphery, the inert gas blown out from the nozzle once fills the nozzle tip surface 55c and its periphery and then diffuses to the periphery. Become.

When the nozzle tip surface 55 c is brought into contact with the base layer 31 and an ultrasonic wave is applied from the ultrasonic vibration element U to the nozzle 55, indium guided to the supply hole 57 is formed by the ultrasonic vibration of the nozzle 55. It is delivered from a fine gap between the base layer 31 and the underlayer 31. And indium comes out to the space part formed between the step part D and the base layer 31, and will be in the state of stirring mixing. That is, indium accumulates in a liquid reservoir shape in the space formed between the base layer 31 and the step portion D, and the peripheral portion of the step portion D is hidden by the accumulated indium, and is scattered from the step portion periphery to the periphery. There is no.
Moreover, the inert gas is supplied from the inert gas supply source to the chamber 59 through the supply pipe p, and the chamber is filled. The inert gas filling the chamber 59 is blown out through a gap between the blowout port 59a provided on the lower end surface of the chamber and the peripheral surface of the nozzle tip portion 55b. The inert gas is diffused to the outside of the chamber 59 after filling the nozzle tip surface 55c and its periphery. In other words, the nozzle front end surface 55c and its periphery are in an inert gas atmosphere, and there is no air.

  Together with these actions, the head moving mechanism 48 described above with reference to FIG. 5 is operated to move the filling head 46, so that indium is lowered from the nozzle front end surface 55c as shown in FIGS. It is applied on the formation 31. Since indium is filled while applying ultrasonic waves, the wettability of indium with respect to the sealing surface or the base layer 31 is improved, and indium can be satisfactorily filled in a desired position. Further, it is possible to continuously fill the melted indium along the base layer 31, and it is possible to form an indium layer 32 that extends along the base layer without any breaks. An alloy layer can be formed by diffusing into the surface portion of the underlayer 31.

During the step of filling indium, since the tip surface 55c of the nozzle 55 and its periphery are in an inert gas atmosphere, the indium layer 32 filled in the base layer 31 has little time to be exposed to the atmosphere. Therefore, the surface of the indium layer does not oxidize and the formation of an oxide film is suppressed. Therefore, after the sealing surface is filled with indium, indium is heated and melted in a vacuum atmosphere in a sealing process described later, and the front substrate 11 and the back substrate 12 are directly or indirectly sealed with the sealing surface 31. When doing this, it is completely sealed and no leakage occurs.
As described above, the inert gas supplied from the gas supply source is a predetermined amount, for example, nitrogen gas or argon gas having a concentration of about 95% containing about 5% of oxygen. That is, if an inert gas having a concentration of 100% is supplied to the periphery of the nozzle tip 55b, the oxidation of the surface of the indium layer 32 is surely suppressed, but the molten indium aggregates and the indium particles are scattered to the periphery, so that the panel effective surface. Taint. If the inert gas contains several percent of oxygen, the indium can be prevented from aggregating indium, and indium can be filled in an ideal state.

In order to prevent the surface oxidation of the indium layer 32, it is necessary to make the nozzle tip surface 55c and its periphery a stable gas, for example, an inert gas atmosphere during indium filling. Thus, the present invention is not limited to the configuration including the chamber 59 communicating with the gas supply source via the supply pipe p.
For example, as shown in FIG. 8, a supply pipe p communicating with a gas supply source is branched into a plurality of pipes in the middle to form spray pipes 59p, and these spray pipes are radially formed around the nozzle tip 55b. The arrangement may be such that each tip opening is attached and fixed toward the nozzle tip surface 55c.

When indium is filled from the nozzle tip surface 55c to the underlayer 31 that is the sealing surface, an inert gas is blown from the spray pipe 59p toward the nozzle tip surface, thereby improperly connecting the nozzle tip surface 55c and its periphery. Use an active gas atmosphere. Therefore, the surface of the indium layer 32 filled in the underlayer 31 is not oxidized, and the generation of an oxide film is suppressed. The structure of the gas supply means forming the inert gas atmosphere is further simplified, and the influence on the cost can be suppressed.
Further, in the step of filling indium, by adjusting either the oscillation output of the ultrasonic wave or the diameter of the supply hole 57 provided in the nozzle 55, the discharge amount of indium is controlled to form indium formed. The thickness, width, etc. of the layer can be adjusted.

On the other hand, as shown in FIG. 4A, when indium is filled on the sealing surface of the side wall 18 sealed on the back substrate 12, here, the base layer 31, the back substrate 12 is similar to the above. Is positioned on the hot panel 42 of the sealing material filling device, and molten indium is continuously filled along the underlayer 31 while applying ultrasonic waves by the filling head 46, and continuously along the underlayer 31. An indium layer 32 is formed.
Next, as shown in FIG. 9, the side wall 18 is sealed to the front substrate 11 having the base layer 31 and the indium layer 32 formed on the sealing surface and the back substrate 12, and the base layer 31 is formed on the upper surface of the side wall. The back side assembly on which the indium layer 32 is formed is held by a jig or the like (not shown) in a state where the sealing surfaces face each other and face each other at a predetermined distance, and is attached to the vacuum processing apparatus. It is thrown in.

As shown in FIG. 10, this vacuum processing apparatus 100 includes a load chamber 101, a baking, an electron beam cleaning chamber 102, a cooling chamber 103, a getter film deposition chamber 104, an assembly chamber 105, and a cooling chamber 106 that are arranged in order. And an unload chamber 107. Each of these chambers is configured as a processing chamber capable of vacuum processing, and all the chambers are evacuated when the FED is manufactured. Adjacent processing chambers are connected by a gate valve or the like.
The rear side assembly and the front substrate 11 that face each other at a predetermined interval are put into the load chamber 101, and after the inside of the load chamber 101 is evacuated, it is sent to the baking and electron beam cleaning chamber 102. In the baking and electron beam cleaning chamber 102, when the high vacuum degree of about 10 ⁻⁵ Pa is reached, the back side assembly and the front substrate 11 are baked by heating to a temperature of about 300 ° C. Fully release the adsorbed gas.

At this temperature, the indium layer (melting point: about 156 ° C.) 32 is melted. However, since the indium layer 32 is formed on the base layer 31 having a high affinity, the indium is held on the base layer 31 without flowing, and the indium layer 32 is held on the electron-emitting device 22 side, the outside of the back substrate, or the phosphor screen. Outflow to the 16 side is prevented.
Further, in the baking and electron beam cleaning chamber 102, the phosphor screen surface of the front substrate 11 and the rear substrate 12 from the electron beam generator (not shown) attached to the baking and electron beam cleaning chamber 102 simultaneously with heating. An electron beam is irradiated on the surface of the electron-emitting device. Since this electron beam is deflected and scanned by a deflection device mounted outside the electron beam generator, the entire surface of the phosphor screen and the surface of the electron-emitting device can be cleaned with an electron beam.

After heating and electron beam cleaning, the rear substrate side assembly and the front substrate 11 are sent to the cooling chamber 103 and cooled to a temperature of about 100 ° C., for example. Subsequently, the rear assembly and the front substrate 11 are sent to a getter film deposition chamber 104, where a Ba film is deposited on the outside of the phosphor screen as a getter film. The Ba film is prevented from being contaminated with oxygen, carbon, or the like, and can maintain an active state.
Next, the back assembly and the front substrate 11 are sent to the assembly chamber 105 where they are heated to 200 ° C. and the indium layer 32 is melted or softened again. In this state, the front substrate 11 and the side wall 18 are joined and pressurized with a predetermined pressure, and then indium is removed and solidified. Thereby, the front substrate 11 and the side wall 18 are sealed by the sealing layer 33 in which the indium layer 32 and the base layer 31 are fused, and the vacuum envelope 10 is formed. The vacuum envelope 10 thus formed is taken out of the unload chamber 107 after being cooled to room temperature in the cooling chamber 106. The FED is completed through the above steps.

According to the FED configured as described above and the manufacturing method thereof, the front end surface 55C of the nozzle 55 and the periphery thereof are made an inert gas atmosphere, and molten indium is supplied from the nozzle front end surface 55c to form a lower surface that is a sealing surface. Since the base layer 31 is filled, it is reliably prevented that an oxide film is generated on the surface of the indium layer 32 in the state where the indium is filled, even though the filling is actually performed in the atmosphere. As a result, there is no leakage when the front substrate 11 and the rear substrate 12 are sealed, and the reliability of sealing can be improved.
By sealing the front substrate 11 and the rear substrate 12 in a vacuum atmosphere, the surface adsorption gas of the substrate can be sufficiently released by the combined use of baking and electron beam cleaning, and the getter film is not oxidized and sufficient. A gas adsorption effect can be obtained. Thereby, FED which can maintain a high degree of vacuum can be obtained. By using indium as the sealing material, foaming at the time of sealing can be suppressed, and an FED having high airtightness and high sealing strength can be obtained. At the same time, by providing the base layer 31 under the indium layer 32, inflow of indium can be prevented and held in place even when indium is melted in the sealing step. Therefore, handling of indium becomes easy, and even a large image display device of 50 inches or more can be easily and reliably sealed.

Furthermore, filling indium while applying ultrasonic waves improves the wettability of indium with respect to the sealing surface or the underlayer 31. Even when indium is used as a metal sealing material, it is good at the desired position. Can be filled. Moreover, the melted indium can be continuously filled along the base layer 31, and an indium layer extending along the base layer can be formed.
When the underlayer 31 is used as in the present embodiment, by filling molten indium while applying ultrasonic waves, a part of indium diffuses into the surface portion of the underlayer 31 at the time of filling, and the alloy layer Can be formed. Therefore, even when indium melts at the time of sealing, the flow of indium can be more reliably prevented and held in place. From the above, it is possible to obtain a method for manufacturing an image display device that is easy to handle a metal sealing material and can be easily and reliably sealed in a vacuum atmosphere.

In the above-described embodiment, sealing is performed with the base layer 31 and the indium layer 32 formed on both the sealing surface of the front substrate 11 and the sealing surface of the side wall 18. For example, the sealing may be performed in a state where the base layer 31 and the indium layer 32 are formed only on the sealing surface of the front substrate 11. In the above-described embodiment, the base layer is formed on the sealing surface and the indium layer is formed thereon. However, the indium layer is directly filled on the sealing surface without using the base layer. It is good also as a structure. Even in this case, by filling the melted indium while applying ultrasonic waves, the wettability of indium with respect to the sealing surface is improved, and indium can be filled continuously at a desired position.
In the above-described embodiment, the field emission type electron emission element is used as the electron emission element. However, the present invention is not limited to this, and other electron emission elements such as a pn type cold cathode element or a surface conduction type electron emission element are used. It may be used. The present invention is also applicable to the manufacture of other image display devices such as a plasma display panel (PDP) and electroluminescence (EL).

The perspective view of the completed FED based on embodiment of this invention. The partial cross section figure of FED based on the same embodiment. The top view which shows the fluorescent substance screen of FED based on the embodiment. The perspective view which shows the state which formed the base layer and the indium layer in the sealing surface of the side wall which comprises the vacuum envelope of FED, and the sealing surface of a front substrate based on the embodiment. The perspective view of the sealing material filling apparatus used in the process of manufacturing FED based on embodiment of this invention. The perspective view which shows the process of filling the sealing surface of a front board | substrate with the filling figure of the filling head of a sealing material filling apparatus and an ultrasonic generator based on the embodiment, and a front substrate. Sectional drawing and a top view of the nozzle at the time of the process filled with indium based on the embodiment. Sectional drawing explaining the structure of the gas supply means in a different example based on the embodiment. Sectional drawing which shows the state which has arrange | positioned the back side assembly and the front board | substrate with which the base layer and the indium layer were formed in the sealing part based on the same embodiment. The figure which shows schematically the vacuum processing apparatus used for manufacture of FED based on the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 12 ... Back substrate, 11 ... Front substrate, 10 ... Vacuum envelope, 22 ... Electron emission element (display element), 55c ... Front end surface of (nozzle), 55 ... Nozzle, 32 ... Indium layer, 18 ... Side wall, 40 ... support stand, 46 ... filling head, 59 ... chamber, 59a ... gas outlet, 59p ... spray tube.

Claims (8)

In a manufacturing method of an image display device comprising a back substrate, an envelope having a front substrate disposed opposite to the back substrate, and a plurality of display elements provided in the envelope,
The nozzle tip surface is applied to the sealing surface between the rear substrate and the front substrate, and the nozzle tip surface and its periphery are set in an atmosphere in which oxygen is reduced, and the sealing surface is filled with a molten metal sealing material. Process,
Filling the sealing surface with a metal sealing material, heating and melting the metal sealing material, and directly or indirectly sealing the back substrate and the front substrate at the sealing surface; ,
A method for manufacturing an image display device, comprising: A rear substrate, a front substrate disposed opposite to the rear substrate, and a side wall disposed between the peripheral portion of the front substrate and the peripheral portion of the rear substrate and sealed to the front substrate and the rear substrate. An envelope having, and a plurality of pixel display elements provided in the envelope,
In the method of manufacturing an image display device, at least one of a sealing surface between the front substrate and the side wall and a sealing surface between the back substrate and the side wall is sealed with a metal sealing material layer.
The nozzle tip surface is applied to the sealing surface between the rear substrate and the front substrate, and the nozzle tip surface and its periphery are set in an atmosphere in which oxygen is reduced, and the sealing surface is filled with a molten metal sealing material. Process,
Filling the sealing surface with a metal sealing material, heating and melting the metal sealing material, and sealing the back substrate, the front substrate, and the side wall with the sealing surface;
A method for manufacturing an image display device, comprising:   The method for manufacturing an image display device according to claim 1, wherein a low melting point metal material is used as the metal sealing material.   4. The method for manufacturing an image display device according to claim 3, wherein the low-melting-point metal material is a simple substance of In, Bi, Sn, or Ga or an alloy containing at least one of them. A sealing material filling device that fills a sealing surface with a metal sealing material in the method of manufacturing an image display device according to any one of claims 1 to 4,
A support base for positioning and supporting an object to be sealed having the sealing surface;
A storage portion for storing the molten metal sealing material, a nozzle for filling the sealing surface with the molten metal sealing material sent from the storage portion, and supplying a stable gas to the tip surface of the nozzle and its periphery. A filling head having a gas supply means for providing a stable gas atmosphere;
A sealing material filling apparatus comprising:   The gas supply means includes a chamber in which at least the nozzle is accommodated and filled with a stable gas supplied from a gas supply source, and a gas blow-out port is opened at a nozzle tip surface of the chamber and a peripheral portion thereof. The sealing material filling apparatus according to claim 5, wherein   6. The sealing according to claim 5, wherein the gas supply means is a blowing pipe that guides the stable gas from the gas supply source and blows the stable gas toward the front end surface of the nozzle and the periphery thereof. Material filling device.   6. A stable gas supplied from a gas supply source to the gas supply means is an inert gas such as nitrogen (N2) gas or argon (Al) gas containing a predetermined amount of oxygen. Item 8. The sealing material filling device according to any one of Items 7 to 9.

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