JP2002184330A - Image display device and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device that can be easily and steadily sealed in vacuum atmosphere and its manufacturing method. SOLUTION: The vacuum outer case of an image display device has a back substrate 12 and a front substrate 11 that are arranged oppositely to each other and a side wall 18 that is provided between these substrates. A fluorescent substrate screen is formed on the inner face of the front substrate and electron emission elements are provided on the back substrate. Between the sealing faces 11a, 18b of the front substrate and the side wall, a primary coat 31 and an indium layer 32 overlapping this primary coat are sealed. The indium layer is formed so as to become thicker from the center part of the straight line portion toward the corner part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device having substrates opposed to each other and a plurality of pixel display elements provided between the substrates, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, as a next-generation light-weight and thin-type flat display device, a display device in which a number of electron-emitting devices are arranged and arranged opposite to a phosphor screen has been developed. As the electron-emitting device, a field emission type or surface conduction type device is assumed. Generally, a display device using a field emission type electron-emitting device is a field emission display (hereinafter, referred to as a field emission display).
A display device using a surface conduction electron-emitting device is called a surface conduction electron-emitting display (hereinafter, referred to as an SED).

For example, an FED generally has a front substrate and a rear substrate opposed to each other with a predetermined gap therebetween.
These substrates constitute a vacuum envelope by sealing peripheral portions of each other via a rectangular frame-shaped side wall.
A phosphor screen is formed on the inner surface of the front substrate, and a number of electron-emitting devices are provided on the inner surface of the rear substrate as electron emission sources for exciting the phosphor to emit light.

In order to support the atmospheric pressure load applied to the rear substrate and the front substrate, a plurality of supporting members are disposed between these substrates. Then, an image is displayed by irradiating the red, green, and blue phosphors constituting the phosphor screen with an electron beam emitted from the electron-emitting device to cause the phosphors to emit light.

In such an FED, the gap between the front substrate and the rear substrate can be set to about 0.2 to 2 mm, which is smaller than that of a cathode ray tube (CRT) currently used as a display of a television or a computer. And lighter,
Thinning can be achieved.

[0006]

SUMMARY OF THE INVENTION The above-mentioned flat panel display device
Then, the degree of vacuum inside the vacuum envelope is set to, for example, 10^-5-10
^-6It is necessary to keep Pa. In the conventional evacuation process, vacuum
Baking process to heat the envelope to about 300 ° C
Release the surface adsorbed gas inside the envelope,
The inside of the vacuum envelope is evacuated through the exhaust pipe
However, such a method releases the surface adsorbed gas sufficiently.
And it is difficult to obtain a high degree of vacuum.

As a method of increasing the degree of vacuum inside the vacuum envelope, the back substrate, the side walls, and the front substrate are put into a vacuum apparatus, and they are subjected to baking and electron beam irradiation in a vacuum atmosphere to adsorb the surface. After the gas is released, a method of forming a getter film and sealing the side wall to the rear substrate and the front substrate using frit glass or the like in a vacuum atmosphere is considered. According to this method, the surface adsorption gas can be sufficiently released by the electron beam cleaning, and the getter film is not oxidized, and a sufficient gas adsorption effect can be obtained. Further, since no exhaust pipe is required, the space of the image display device is not wasted.

[0008] However, when sealing is performed using frit glass in a vacuum, it is necessary to heat the frit glass to a high temperature of 400 ° C. or more. There is a problem that the hermeticity and sealing strength of the enclosure are deteriorated, and the reliability is reduced. In addition, due to the characteristics of the electron-emitting device, it may be better to avoid raising the temperature to 400 ° C. or higher. In such a case, a method of sealing with frit glass is not preferable.

The present invention has been made in view of the above points, and an object of the present invention is to provide an image display device capable of easily performing sealing in a vacuum atmosphere, and a method of manufacturing the same.

[0010]

In order to achieve the above object, an image display apparatus according to the present invention comprises an envelope having a rear substrate, a front substrate opposed to the rear substrate, and A plurality of pixel display elements provided inside the container, wherein a sealing surface between the front substrate and the rear substrate is sealed with each other by a metal sealing material layer extending along the sealing surface. And wherein at least a part of the metal sealing material layer has a larger cross-sectional area than other parts.

Further, another image display device according to the present invention comprises a rear substrate, a front substrate opposed to the rear substrate, and a peripheral portion of the front substrate and a peripheral portion of the rear substrate. And an envelope having a side wall sealed to the front substrate and the rear substrate, and a plurality of pixel display elements provided inside the envelope, and At least one of the sealing surface between, and the sealing surface between the back substrate and the side wall are sealed to each other by a metal sealing material layer, at least a part of the metal sealing material layer than other parts Are characterized by having a large cross-sectional area.

Further, according to the image display device of the present invention, at least a part of the metal sealing material layer is formed to be thicker or wider than other parts.

According to the image display device of the present invention, the sealing surface extends along the peripheral edge of the front substrate or the rear substrate and has a plurality of straight portions and corners. Forming a frame, the metal sealing material layer is formed such that in each linear portion of the sealing surface, the thickness is increased from the center of each linear portion toward the corner, or the width is increased. It is characterized by.

In the image display device according to the present invention,
As the metal sealing material, a low melting point metal material having a melting point of 350 ° C. or less is used, for example, indium or an alloy containing indium.

According to the image display device configured as described above, by directly or indirectly sealing the front substrate and the rear substrate using the metal sealing material layer, the electronic device provided on the rear substrate is provided. The sealing can be performed at a low temperature without thermally damaging the emitting element and the like. Further, unlike the case where frit glass is used, many air bubbles are not generated, and the airtightness and sealing strength of the vacuum envelope can be improved.

At the same time, according to the present invention, at least a part of the metal sealing material layer has a larger cross-sectional area than the other parts, so that no leakage or the like occurs and no excess metal sealing occurs. The sealing surface can be securely sealed without the material protruding onto the wiring or the like. That is, since the sealing with the metal sealing material is performed in a state where the metal sealing material is melted, if the filling amount of the metal sealing material is small, sufficient sealing is not performed and a leak or the like may occur. Conversely, if the filling amount of the metal sealing material is large, the molten metal sealing material may protrude into undesired portions, and display performance as an image display device may be deteriorated. Therefore, by providing a portion having a large cross-sectional area in the metal sealing material layer, the filling amount of the metal sealing material is sufficiently set, and even if excess molten metal sealing material is generated at the time of sealing, this Excess molten metal sealing material can be positively guided to the portion having the large cross-sectional area. Therefore, by providing the portion having the large cross-sectional area at a desired position set in advance, even if the surplus molten metal sealing material is generated, it is ensured that the surplus molten metal sealing material flows out to an undesired portion. Can be prevented. As a result, it is possible to obtain an image display device that can easily handle the metal sealing material and can easily and reliably perform sealing in a vacuum atmosphere.

On the other hand, a method of manufacturing an image display device according to the present invention includes a rear substrate and a front substrate which is directly or indirectly sealed to the rear substrate by a metal sealing material and is arranged to face the rear substrate. In a method for manufacturing an image display device including an envelope and a plurality of pixel display elements provided inside the envelope, a method for manufacturing the image display device includes a sealing surface between the rear substrate and the front substrate. Applying a metal sealing material to form a metal sealing material layer, and after forming the metal sealing layer, heating the back substrate and the front substrate in a vacuum atmosphere to form the metal sealing material layer. In a molten state, the rear substrate and the front substrate are moved in a direction approaching each other at a predetermined sealing speed, and the rear substrate and the front substrate are sealed at the sealing surface with the metal sealing material. And applying along the sealing surface. The thickness t of the metal sealing layer, the thickness of the metal sealing layer after the sealing d, and the sealing speed s
Is characterized by satisfying the relationship of s / d = 0.66 or less and t / d = 3.9 or less.

In the manufacturing method according to the present invention, a low melting point metal material having a melting point of 350 ° C. or less is used as the metal sealing material, for example, indium or an alloy containing indium.

According to such a method of manufacturing an image display device, the front and rear substrates are directly or indirectly sealed using the metal sealing material layer, so that the electron emission provided on the rear substrate is provided. Sealing can be performed at a low temperature without thermally damaging the element and the like. Further, unlike the case where frit glass is used, many air bubbles are not generated, and the airtightness and sealing strength of the vacuum envelope can be improved. At the same time, by satisfying the relationship of s / d = 0.66 or less and t / d = 3.9 or less, that is, setting the sealing speed sufficiently low according to the thickness of the metal sealing material layer. Thereby, the molten metal sealing material can be satisfactorily distributed over almost the entire area of the sealing surface, and even if excess molten metal sealing material is generated, the excess molten metal sealing material is removed. It can be positively guided to a desired site. Therefore, it is possible to obtain a method of manufacturing an image display device that can easily handle a metal sealing material and can easily and reliably perform sealing in a vacuum atmosphere.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment in which an image display device of the present invention is applied to an FED will be described in detail with reference to the drawings. As shown in FIGS. 1 and 2, the FED includes a front substrate 11 and a rear substrate 12 each made of rectangular glass as an insulating substrate, and these substrates have a gap of about 1.5 to 3.0 mm. They are placed facing each other. Then, the front substrate 11 and the rear substrate 1
Reference numeral 2 denotes a flat rectangular vacuum envelope 10 whose peripheral edges are sealed via a rectangular frame-shaped side wall 18 and whose inside is maintained in a vacuum state.

Inside the vacuum envelope 10, a back substrate 12
And to support the atmospheric pressure load applied to the front substrate 11,
A plurality of support members 14 are provided. These support members 14 extend in a direction parallel to the long sides of the vacuum envelope 10 and are arranged at predetermined intervals along a direction parallel to the short sides. 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. 1 to FIG.
The sealing surface between the second substrate 2 and the side wall 18 is sealed with a low-melting glass 30 such as frit glass, and the sealing surface between the front substrate 11 and the side wall 18 is formed on the lower surface formed on the sealing surface. Formation 3
1 and an indium layer 32 formed on the underlayer are sealed by a sealing layer 33 which is fused.

The sealing surfaces of the front substrate 11, the rear substrate 12, and the side wall 18 have a rectangular frame shape corresponding to the side wall 18. That is, the upper surface and the lower surface of the side wall 18 form the rectangular frame-shaped sealing surfaces 18a and 18b, respectively. The sealing surface 11a of the front substrate 11 facing the upper sealing surface 18a of the side wall 18 has a rectangular frame shape extending along the peripheral edge of the inner surface of the front substrate, and is substantially similar to the sealing surface 18a of the side wall 18. They have the same dimensions and the same width. Also, the side wall 18
The sealing surface 12a of the rear substrate 12 facing the lower sealing surface 18b of the first side has a rectangular frame shape extending along the peripheral portion of the inner surface of the rear substrate, and has substantially the same dimensions and the same size as the sealing surface 18b of the side wall 18. Has become the width of. Therefore, these sealing surfaces 18
a, 18b, 11a, and 12a have two sets of straight portions and four corners, respectively. The sealing surface 18b of the side wall 18 and the sealing surface 12a of the rear substrate 12 are formed by frit glass 30. Sealed to each other. In this case, as shown in FIG. 3, the frit glass layer extending along each linear portion of the sealing surfaces 12a and 18b has a thicker central portion of the linear portion and approaches the both ends, that is, approaches the corner. Is formed so as to be thinner. By sealing the rear substrate 12 and the side wall 18 using such frit glass 30, each straight line portion of the side wall 18 corresponds to the thickness distribution of the frit glass layer, and the central portion thereof corresponds to the front substrate 11.
It is slightly curved so as to be convex on the side. The gap between the sealing surface 18a on the upper surface side of the side wall 18 and the sealing surface 11a of the front substrate 11 is narrow at the center of each straight line portion of the sealing surface, and approaches the both ends, that is, It gets wider as you get closer to the department.

On the other hand, the sealing surface 11a of the front substrate 11 and the sealing surface 18a of the side wall 18 are formed by an underlayer 31 formed on each sealing surface and an indium layer 32 formed on the underlayer. It is sealed by the fused sealing layer 33. Here, as described above, the gap between the sealing surface 11a of the front substrate 11 and the sealing surface 18a of the side wall 18 is narrow at the center of each straight line portion of the sealing surface and approaches the both ends, In other words, because it gets wider as you approach the corner,
The indium layer 30 filled between these sealing surfaces,
Each straight portion of the sealing surface is formed to be thicker from the center of the straight portion to the corner. That is, the indium layer 30 is formed such that the cross-sectional area is larger at the corners of the straight portions of the sealing surfaces 11a and 18a than at the center of the straight portions. For example, the indium layer 30
In each of the straight portions of the sealing surface, the thickness at the center of the straight portion is about 0.15 mm, and the thickness at the corner is about 0.3
mm.

As shown in FIG. 4, 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 emitting three colors of red, green, and blue, and a matrix-shaped black light absorbing portion 20. The above-described support member 14 is placed so as to be hidden by the shadow of 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 rear substrate 12, a large number of field emission type electrons each emitting an electron beam are provided as electron emission sources for exciting the phosphor layers R, G, and B. An emission element 22 is provided. These electron-emitting devices 22 are arranged in a plurality of columns and a plurality of rows corresponding to each pixel. More specifically, a conductive cathode layer 24 is formed on the inner surface of the rear substrate 12, and a silicon dioxide film 26 having a number of cavities 25 is formed on the conductive cathode layer. On the silicon dioxide film 26, a gate electrode 28 made of molybdenum, niobium or the like is formed. 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 back substrate 12, a matrix-like wiring (not shown) connected to the electron-emitting device 22 is formed. These wirings are drawn out from at least one long side and one short side of the back substrate 12.

In the FED configured as described above,
The video signal is input to the electron-emitting device 22 and the gate electrode 28 formed in a simple matrix system. On the basis of the electron-emitting device 22, when the brightness is the highest, +
A gate voltage of 100 V is applied. Further, +10 kV is applied to the phosphor screen 16. The size of the electron beam emitted from the electron-emitting device 22 is modulated by the voltage of the gate electrode 28, and the electron beam excites the phosphor layer of the phosphor screen 16 to emit light, thereby displaying an image. .

Next, a method of manufacturing the FED configured as described above will be described in detail. First, the phosphor screen 16 is formed on a plate glass to be the front substrate 11. For this, a glass sheet having the same size as the front substrate 11 is prepared, and a stripe pattern of the phosphor layer is formed on the glass sheet by a plotter machine. Exposure is achieved by placing the plate glass on which the phosphor stripe pattern is formed and the plate glass for the front substrate on a positioning jig and setting it on an exposure table.
Develop to produce phosphor screen 16.

Subsequently, the electron-emitting devices 22 are formed on the glass plate for the rear substrate. In this case, a matrix-shaped conductive cathode layer is formed on a sheet 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.

Thereafter, a metal film for forming a gate electrode such as molybdenum or niobium is formed on the insulating film by, for example, a sputtering method or an electron beam evaporation method. Next, a resist pattern having a shape corresponding to the gate electrode to be formed is formed on the metal film by lithography. Using the resist pattern as a mask, the metal film is etched by a wet etching method or a dry etching method to form a gate electrode 28.

Next, the cavity 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 release layer made of, for example, aluminum, nickel, or cobalt is formed on the gate electrode 28 by performing electron beam evaporation from a direction inclined at a predetermined angle with respect to the rear substrate surface. Thereafter, for example, molybdenum as a material for forming a cathode is deposited by an electron beam evaporation method from a direction perpendicular to the surface of the rear substrate. Thus, the electron-emitting device 22 is formed inside each cavity 25. Subsequently, the release layer is removed by a lift-off method together with the metal film formed thereon.

Subsequently, the periphery of the rear substrate 12 on which the electron-emitting devices 22 are formed and the rectangular frame-shaped side wall 18 are sealed to each other by frit glass 30 in the atmosphere. In this case, as shown in FIG.
After the frit glass 30 is applied along, the frit glass is pressed from above by a rectangular shaping frame 40 having a pressing surface 40a in which each linear portion is concavely curved, and shaped, for example. Thereby, the frit glass layer extending along each straight line portion of the sealing surface 12a is shaped such that the central portion of the straight line portion is thick and becomes thinner as approaching the corner.

By sealing the rear substrate 12 and the side wall 18 at atmospheric pressure using the frit glass 30 shaped as described above, each linear portion of the side wall 18 has a thickness distribution of the frit glass layer. And the central portion is sealed in a slightly curved state so as to be convex toward the front substrate 11 side. At the same time as the sealing of the side wall 18, the plurality of support members 14 are placed on the back substrate 12 in the atmosphere in the frit glass 30.
To seal.

Subsequently, the back substrate 12 and the front substrate 11 are sealed to each other via the side wall 18. In this case, as shown in FIG. 6, first, the underlayer 31 is formed over the entire periphery of the upper surface of the side wall 18 to be the sealing surface 18b. The width of the base layer 31 is formed to be slightly smaller than the width of the upper surface of the side wall 18, that is, the width of the sealing surface 18a.

As described above, the sealing surface 11a on the front substrate 11 side has a rectangular frame shape along the peripheral portion of the inner surface of the front substrate and has two sets of straight portions and four corner portions facing each other. And have substantially the same dimensions and the same width as the sealing surface 18a of the side wall 18. Then, as shown in FIG. 7, an underlayer 31 is formed over the entire circumference on the sealing surface 11a. The width of the underlayer 31 is formed slightly smaller than the width of the sealing surface 11a. The underlayer 31 is formed by applying a silver paste.

Subsequently, as shown in FIG. 6 and FIG. 7, indium is applied as a metal sealing material on each of the underlayers 31, and an indium layer 32 extending over the entire periphery of each of the underlayers 31 is formed. Form. The width of the indium layer 32 is
The indium layer is formed to be narrower than the width of the underlayer 31, and is applied in such a manner that both side edges of the indium layer are separated from the both side edges of the underlayer 31 by a predetermined gap. For example, if the width of the side wall 18 is 9 mm, the width of the underlayer 31 is 8 mm, and the width of the indium layer 32 is about 6 mm.

The metal sealing material has a melting point of about 3
It is desirable to use a low melting point metal material excellent in adhesion and bonding at 50 ° C. or lower. Indium (In) used in the present embodiment has a melting point as low as 156.7 ° C.,
It has excellent features such as low vapor pressure, soft and strong impact resistance, and does not become brittle even at low temperatures. In addition, it can be directly bonded to glass depending on conditions, and is a material suitable for the purpose of the present invention.

Further, as the low melting point metal material, an alloy to which elements such as silver oxide, silver, gold, copper, aluminum, zinc, tin and the like are added alone or in combination can be used instead of In alone. For example, in the eutectic alloy of In97% -Ag3%, the melting point is further reduced 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 kinds of metals, the melting point may not be determined singly. Generally, in such a case, the liquidus temperature and the solidus temperature are defined. The former is the temperature at which part of the alloy starts to solidify when the temperature is lowered from the liquid state, and the latter is the temperature at which all of the alloy solidifies. In the present embodiment, for convenience of explanation, the expression of melting point is used in such a case,
The solidus temperature is called the melting point.

On the other hand, for the underlayer 31 described above, a material having good wettability and airtightness with respect to the metal sealing material, that is, a material having high affinity for the metal sealing material is used. In addition to the silver paste described above, a metal paste such as gold, aluminum, nickel, cobalt, and copper can be used. In addition to the metal paste, as the base layer 31, a metal plating layer of silver, gold, aluminum, nickel, cobalt, copper, or the like, a deposited film, or a glass material layer can be used.

Next, the side wall 18 is sealed to the front substrate 11 in which the underlayer 31 and the indium layer 32 are formed on the sealing surface 11a, and the underlayer is formed on the sealing surface 18a of the side wall. 8 and 9 with the sealing surfaces 11a and 18a facing each other, as shown in FIG. 8 and FIG.
In addition, it is held by a jig or the like in a state where it faces at a predetermined distance, and is put into a vacuum processing apparatus.

As shown in FIG. 10, this vacuum processing apparatus 1
Reference numeral 00 includes a load chamber 101, a baking / electron beam cleaning chamber 102, a cooling chamber 103, a getter film deposition chamber 104, an assembling chamber 105, a cooling chamber 106, and an unload chamber 107 provided in this order. . Each of these chambers is configured as a processing chamber capable of performing vacuum processing, and all the chambers are evacuated during the manufacture of the FED. Adjacent processing chambers are connected by a gate valve or the like.

The rear assembly and the front substrate 11 facing each other at a predetermined interval are put into the load chamber 101, and the inside of the load chamber 101 is evacuated to a vacuum atmosphere. In the baking and electron beam cleaning chamber 102, when a high degree of vacuum of about 10 ⁻⁵ Pa is reached, the back assembly and the front substrate are heated to a temperature of about 300 ° C. and baked, and the surface of each member is adsorbed. Allow sufficient gas to be released.

At this temperature, the indium layer (having a melting point of about 156)
C) 32 melts. 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 provided on the electron emission element 22 side, the outside of the back substrate, or the phosphor screen. Outflow to the 16 side is prevented.

In the baking / electron beam cleaning chamber 102, simultaneously with heating, an electron beam generator (not shown) attached to the baking / electron beam cleaning chamber 102 sends the phosphor screen surface of the front substrate 11 and the back surface. An electron beam is irradiated on the electron-emitting device surface of the substrate 12. Since the electron beam is deflected and scanned by a deflecting device mounted outside the electron beam generator, it is possible to clean the entire surface of the phosphor screen surface and the electron emission element surface with the 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, for example, about 1 mm.
Cool to a temperature of 00 ° C. Subsequently, the back-side assembly and the front substrate 11 are sent to a getter film deposition chamber 104, where a Ba film is deposited as a getter film outside the phosphor screen. The surface of the Ba film is prevented from being contaminated with oxygen, carbon, or the like, and can maintain an active state.

Next, the rear assembly and the front substrate 11 are sent to an assembly chamber 105, where they are heated to 200 ° C., and the indium layer 32 is again melted or softened into a liquid state.
In this state, the rear assembly and the front substrate 11 are moved in a direction approaching each other at a predetermined sealing speed, and the front substrate 11 is moved.
After joining with the side wall 18 and applying a predetermined pressure, the indium is cooled and solidified. Thereby, the front substrate 1
The first sealing surface 11a and the sealing surface 18a of the side wall 18 are sealed by a sealing layer 33 in which the indium layer 32 and the base layer 31 are fused, and the vacuum envelope 10 is formed.

Here, as described above, since each straight portion of the side wall 18 is slightly curved so that the central portion is convex toward the front substrate 11, the sealing on the upper surface side of the side wall 18 is performed. The gap between the surface 18a and the sealing surface 11a of the front substrate 11 is narrower at the center of each linear portion of the sealing surface, and becomes wider toward both ends, that is, closer to the corners.

Therefore, in a state where indium is molten,
When the back side assembly and the front substrate 11 are moved in a direction approaching each other at a predetermined sealing speed to join the front substrate 11 and the side wall 18, even if extra molten indium is generated, this extra Indium is guided from the center to the corners of each linear portion of the sealing surface, that is, toward a portion having a large cross-sectional area of the indium layer. Then, even when surplus indium leaks out of the sealing surface, the surplus indium leaks out from a corner of the sealing surface.

Therefore, even when the indium layer 32 is formed in a sufficient amount to ensure the sealing, the surplus indium does not flow onto the phosphor screen 16, the wiring, or the electron-emitting device side. As a result, the sealing surface can be reliably sealed without deteriorating the display performance of the FED.

Further, in the present embodiment, the sealing speed when the rear assembly and the front substrate 11 are moved in a direction approaching each other at the time of sealing is set to a relatively low speed. That is, when the sum of the thicknesses of the indium layers 32 applied along the sealing surfaces 11a and 18a is t, the thickness of the indium layer after sealing is d, and the sealing speed is s, The values are set to satisfy the following relationship. s / d = 0.66 or less and t / d = 3.9 or less By setting the respective values so as to satisfy the above relationship, the back side assembly and the front substrate 1 are in a state where indium is melted.
1 are moved in a direction approaching each other at a predetermined sealing speed, and the front substrate 11 and the side wall 18 are joined together,
Even when excess molten indium is generated, the excess indium is gradually removed from the center to the corner of each straight line portion of the sealing surface, that is, toward a portion having a large cross-sectional area of the indium layer. It can be surely guided.

Therefore, even when the indium layer 32 is formed in a sufficient amount to ensure the sealing, it is further ensured that the surplus indium flows out onto the phosphor screen 16, the wiring, or the electron-emitting device side. As a result, the sealing surface can be securely sealed without deteriorating the display performance of the FED.

The present inventors have determined that the sealing speed s, the coating thickness t of the indium layer, and the thickness of the indium layer after sealing are d,
Was varied to experiment the amount of molten indium leakage. The experimental results are shown in Table 1 below.

[0054]

[Table 1]

As can be seen from Table 1, s / d = 0.
66 or less, and t / d = 3.9 or less, preferably s
By satisfying the relationship of /d=0.50 or less and t / d = 2.0 or less, leakage of molten indium can be eliminated. The coating thickness t of the indium layer is 0.2
It is desirable that the gap thickness of the indium layer, that is, the thickness d of the indium layer after sealing, is set to about 0.1 to 0.5 mm.

The vacuum envelope 10 thus formed is
Is cooled to room temperature in the cooling chamber 106 and then taken out of the unloading chamber 107. By the above process, FED
Is completed.

According to the FED configured as described above and the method of manufacturing the same, the front substrate 11 and the rear substrate 12 are sealed in a vacuum atmosphere, so that the surface of the substrate can be combined with baking and electron beam cleaning. The adsorbed gas can be sufficiently released, and the getter film is not oxidized, so that a sufficient gas adsorbing effect can be obtained. Thereby, an FED that can maintain a high degree of vacuum can be obtained.

Further, by using indium as a sealing material, foaming at the time of sealing can be suppressed, and an FED having high airtightness and sealing strength can be obtained.

Further, according to the present embodiment, the indium layer 32 formed along the sealing surface is thicker in each straight portion of the sealing surface from the center to the corner.
That is, it is formed so as to have a large cross-sectional area.
Therefore, even if extra indium melts during sealing, this extra indium is positively guided to the corners of the sealing surface and flows out onto the phosphor screen 16, wiring, or the electron-emitting device side. Can be prevented. Therefore, handling of indium becomes simple, and even in a large-sized image display device of 50 inches or more, it is possible to easily and reliably perform sealing in a vacuum atmosphere without deteriorating the display performance of the FED. An image display device and a manufacturing method thereof can be obtained.

Further, according to the present embodiment, at the time of sealing with indium, the sealing speed s, the coating thickness t of the indium layer,
The relation of the thickness d of the indium layer after sealing is s / d = 0.6
By setting the ratio to 6 or less and t / d = 3.9 or less, the molten indium can be surely guided to a desired site, and a sufficient amount of the indium layer 3 can be securely sealed.
2 can prevent the surplus indium from flowing onto the phosphor screen 16, the wiring, or the electron-emitting device side more reliably, and as a result, the sealing surface without deteriorating the display performance of the FED. Can be reliably sealed.

In the above-described embodiment, the sealing is performed in a state where the underlayer 31 and the indium layer 32 are formed on both the sealing surface 11a of the front substrate 11 and the sealing surface 18a of the side wall 18. But only on one of the sealing surfaces,
For example, as shown in FIG.
The sealing may be performed in a state in which the underlayer 31 and the indium layer 32 are formed only on 1a.

In the above-described embodiment, the indium layer 32 is formed so as to increase in thickness from the center to the corners of each linear portion of the sealing surface.
As shown in FIG. 2, the thickness of the indium layer 32 is fixed,
Each linear portion of the sealing surface may be formed so that the width increases from the center to the corner. Also in such a configuration, the cross-sectional area of the straight portion of the indium layer is larger at the corners than at the center. Therefore, at the time of sealing, in each linear portion of the sealing surface, the molten indium can be positively guided from the central portion toward the corner portion, and the same operation and effect as in the above-described embodiment can be obtained. .

In the above-described embodiment, the cross-sectional area of each linear portion of the indium layer gradually increases from the center to the corner. The cross-sectional area of the corner may be locally increased. Furthermore, in the indium layer, the portion where the cross-sectional area is increased is not limited to the corner, and can be arbitrarily selected as needed, and may be, for example, the center of each straight portion or the center of at least one straight portion. .

In addition, the present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention. For example, the space between the rear substrate and the side wall may be sealed by a sealing layer in which the underlayer 31 and the indium layer 32 are fused as described above. Alternatively, a configuration may be employed in which one peripheral portion of the front substrate or the rear substrate is formed by bending, and these substrates are directly sealed without passing through the side wall. Further, although the indium layer is provided so as to overlap the underlayer, the underlayer may be omitted.

In the above-described embodiment, a field emission type electron-emitting device is used as an electron-emitting device. However, the present invention is not limited to this, and other devices such as a pn-type cold cathode device or a surface conduction type electron-emitting device may be used. May be used. The present invention is also applicable to other image display devices such as a plasma display panel (PDP) and electroluminescence (EL).

[0066]

As described above in detail, according to the present invention, the substrates are sealed with each other by using the metal sealing material layer, and at least a part of the metal sealing material layer is formed by other parts. By forming so as to have a larger cross-sectional area, it is possible to easily and reliably perform sealing in a vacuum atmosphere and to provide an image display device with high airtightness and high sealing strength. Further, at the time of sealing, the thickness t of the metal sealing material layer formed along the sealing surface, the thickness d of the metal sealing material layer after sealing, and the sealing speed s are s / s. d = 0.
By satisfying the relationship of 66 or less and t / d = 3.9 or less, it is possible to provide a method of manufacturing an image display device that can easily and reliably perform sealing in a vacuum atmosphere.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an FED according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG. 1;

FIG. 3 is a sectional view taken along line BB in FIG. 1;

FIG. 4 is a plan view showing a phosphor screen of the FED.

FIG. 5 is a perspective view showing a state in which a frit glass layer is formed on a sealing surface of a back substrate constituting the vacuum envelope of the FED.

FIG. 6 is a perspective view showing a state in which a base layer and an indium layer are formed on a sealing surface of a side wall constituting the vacuum envelope.

FIG. 7 is a plan view and a perspective view showing a state in which a base layer and an indium layer are formed on a sealing surface of a front substrate constituting the vacuum envelope.

FIG. 8 is a cross-sectional view showing a state in which a back-side assembly in which a base layer and an indium layer are formed in the sealing portion and a front substrate are arranged to face each other.

FIG. 9 is a side view showing a state in which a back-side assembly in which a base layer and an indium layer are formed in the sealing portion and a front substrate are arranged to face each other.

FIG. 10 is a view schematically showing a vacuum processing apparatus used for manufacturing the FED.

FIG. 11 is a sectional view showing a state in which a base layer and an indium layer are formed on a sealing surface of a front substrate in a step of forming a vacuum envelope of an FED according to another embodiment of the present invention.

FIG. 12 is a plan view showing a state in which a base layer and an indium layer are formed on a sealing surface of a front substrate in a step of forming a vacuum envelope of an FED according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Vacuum envelope 11 ... Front board 12 ... Back board 11a, 12a, 18a, 18b ... Sealing surface 14 ... Support member 16 ... Phosphor screen 18 ... Side wall 22 ... Electron emission element 30 ... Frit glass 31 ... Underlayer 32: indium layer 100: vacuum processing device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Nishimura 1-9-2, Hara-cho, Fukaya-shi, Saitama F-term in the Toshiba Fukaya plant (reference) 5C012 AA05 BC03 5C032 AA01 BB18 5C036 EE14 EE17 EF01 EF06 EF09 EG05 EG06 EH01 EH26

Claims (19)

[Claims] An enclosure having a rear substrate, a front substrate opposed to the rear substrate, and a plurality of pixel display elements provided inside the enclosure; The sealing surface between the back substrate is sealed to each other by a metal sealing material layer extending along the sealing surface, at least a part of the metal sealing material layer is larger than other parts An image display device having a cross-sectional area. 2. A rear substrate, a front substrate opposed to the rear substrate, and disposed between a peripheral portion of the front substrate and a peripheral portion of the rear substrate and sealed to the front substrate and the rear substrate. An envelope having side walls, and a plurality of pixel display elements provided inside the envelope,
At least one of a sealing surface between the front substrate and the side wall and a sealing surface between the rear substrate and the side wall are sealed to each other by a metal sealing material layer, An image display device, wherein at least a part of the layer has a larger cross-sectional area than another part. 3. The image display device according to claim 1, wherein at least a part of the metal sealing material layer is formed thicker than other parts. 4. The metal sealing material layer according to claim 1, wherein the sealing surface extends along a peripheral portion of the front substrate or the rear substrate and has a rectangular frame shape having a plurality of linear portions and corner portions. 3. The image display device according to claim 1, wherein each of the straight portions of the sealing surface is formed to be thicker from a central portion of each straight portion toward a corner. 5. The gap between the sealing surfaces between the front substrate and the rear substrate is at least partially different in size, and the metal sealing material layer fills the gap between the sealing surfaces. The image display device according to any one of claims 1 to 4, wherein: 6. The image display device according to claim 1, wherein at least a part of the metal sealing material layer is formed to have a wider width than other parts. 7. The metal sealing material layer, wherein the sealing surface extends along the peripheral edge of the front substrate or the rear substrate and has a rectangular frame shape having a plurality of straight portions and corner portions. 3. The image display device according to claim 1, wherein each of the straight portions of the sealing surface is formed so as to increase in width as approaching a corner from a center of the straight portion. 4. . 8. The image display device according to claim 1, wherein the metal sealing material layer is formed of a low melting point metal material having a melting point of 350 ° C. or less. 9. The method according to claim 8, wherein the low melting point metal material is indium or an alloy containing indium.
The image display device as described in the above. 10. An underlayer provided along the sealing surface and different from the metal sealing material layer, wherein the metal sealing material layer is formed so as to overlap the underlayer. The image display device according to claim 1, wherein: 11. The underlayer is made of silver, gold, aluminum,
2. A metal paste containing at least one of nickel, cobalt, and copper.
0. The image display device according to 0. 12. The method according to claim 12, wherein the underlayer is silver, gold, aluminum,
The image display device according to claim 10, wherein the image display device is formed of a metal plating layer or a deposition film containing at least one of nickel, cobalt, and copper, or a glass material. 13. An envelope having a rear substrate, a front substrate opposed to the rear substrate, a phosphor screen formed on an inner surface of the front substrate, and a phosphor screen provided on the rear substrate, An electron emission source that emits an electron beam to the body screen to cause the phosphor screen to emit light, wherein a sealing surface between the front substrate and the rear substrate extends along the sealing surface. An image display device which is sealed to each other by a material layer, wherein at least a part of the metal sealing material layer has a larger cross-sectional area than other parts. 14. An envelope having a rear substrate and a front substrate directly or indirectly sealed to said rear substrate by a metal sealing material and disposed opposite to said rear substrate, and inside said envelope. A plurality of pixel display elements provided;
A method of manufacturing an image display device, comprising: applying a metal sealing material along a sealing surface between the rear substrate and the front substrate to form a metal sealing material layer; After forming the adhesion layer, the rear substrate and the front substrate are heated in a vacuum atmosphere, and the rear substrate and the front substrate approach each other at a predetermined sealing speed while the metal sealing material layer is melted. Moving in the direction, sealing the back substrate and the front substrate with the sealing surface with the metal sealing material, and the metal sealing material layer applied along the sealing surface Thickness t,
The thickness d of the metal sealing material layer after sealing and the sealing speed s satisfy a relationship of s / d = 0.66 or less and t / d = 3.9 or less. Manufacturing method of an image display device. 15. The method according to claim 14, wherein in the step of forming the metal sealing material layer, at least a part of the metal sealing material layer is formed so as to have a larger sectional area than other portions. 3. The method for manufacturing an image display device according to 1. 16. The method according to claim 15, wherein in the step of forming the metal sealing material layer, at least a portion of the metal sealing material layer is formed to be thicker than other portions.
3. The method for manufacturing an image display device according to 1. 17. The method according to claim 15, wherein in the step of forming the metal sealing material layer, at least a part of the metal sealing material layer is formed so as to be wider than other parts. A manufacturing method of the image display device described in the above. 18. The method according to claim 14, wherein the metal sealing material layer is formed of a low melting point metal material having a melting point of 350 ° C. or less. . 19. The method according to claim 18, wherein the low melting point metal material is indium or an alloy containing indium.