JP2007207436A - Image display device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display device comparatively inexpensively manufacturable without deteriorating electron source characteristics. <P>SOLUTION: This image display device has a front substrate 11 and a back substrate 12 disposed face to face, a first sealing part 33 provided in the peripheral fringe parts of the front substrate and the back substrate while sealing between the peripheral fringe parts, and a second sealing part 40 provided on the outside of the first sealing part while sealing between the front substrate and the second substrate and formed of a sealing material cured at a temperature lower than the melting temperature of a first sealing material. A first exhausting vent 50a to exhaust a space specified by the front substrate, the back substrate, and the first sealing part, and a second exhaust vent 50b to exhaust a space between the first and second sealing parts are provided in the image display device. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image display device having a substrate disposed oppositely and a manufacturing method thereof.

  2. Description of the Related Art In recent years, various flat display devices have been developed as next-generation lightweight and thin display devices that replace cathode ray tubes (hereinafter referred to as CRTs). Such flat display devices include a liquid crystal display (hereinafter referred to as LCD) that controls the intensity of light by utilizing the orientation of liquid crystal, and a plasma display panel (hereinafter referred to as PDP) that emits phosphors by ultraviolet rays of plasma discharge. Field emission display (hereinafter referred to as FED) that emits a phosphor with an electron beam of a field emission electron emitter, and a surface conduction electron emission display that emits a phosphor with an electron beam of a surface conduction electron emitter. (Hereinafter referred to as SED).

  For example, FEDs and SEDs generally have a front substrate and a back substrate that are opposed to each other with a predetermined gap, and these substrates are vacuum-bonded by bonding their peripheral parts to each other via a rectangular frame-shaped side wall. The envelope is configured. 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 that excite the phosphor to emit light. 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 substantially the ground potential, 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.

  With such FEDs and SEDs, the thickness of the display device can be reduced to a few millimeters, and it is lighter and thinner than CRTs currently used as television and computer displays. can do.

  In the FED and SED as described above, the inside of the envelope needs to be evacuated. Moreover, it is necessary to fill the discharge gas after evacuating the PDP once.

  As a means for evacuating the envelope, the front substrate, the rear substrate, and the side wall, which are constituent members of the envelope, are joined to each other by heating them in the atmosphere with an appropriate sealing material, and provided on the front substrate or the rear substrate. There is a method of vacuum-sealing the exhaust pipe after exhausting the inside of the envelope from the exhaust pipe. As the sealing material, frit glass that is generally reliable over a long period of time is used.

However, in the FED and SED, when the substrate or the like is heated in the air in the sealing process, the characteristics of the electron source are deteriorated, and there is a problem that the image quality as an image display device is greatly affected. As a method for solving this problem, a method has been proposed in which final assembly of a front substrate and a rear substrate constituting an envelope is performed in a vacuum chamber (for example, Patent Document 1).
JP 2002-319346 A

  However, when the final assembly is performed in the vacuum chamber as described above, it is necessary to install various assembling apparatuses in the vacuum processing apparatus, and the vacuum processing tank becomes large and the entire apparatus becomes expensive.

  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 that can be manufactured at a relatively low cost without deteriorating electron source characteristics and a method for manufacturing the same. .

  In order to solve the above-described problems, an image display device according to an aspect of the present invention is provided on a front substrate and a rear substrate that are arranged to face each other with a gap therebetween, and on a peripheral portion of the front substrate and the rear substrate. A first sealing portion formed of a first sealing material that seals between the peripheral portions, and an outer side of the first sealing portion, and seals between the peripheral portions of the front substrate and the back substrate. And a second sealing portion formed of a second sealing material that cures at a temperature lower than the melting temperature of the first sealing material, and defined by the front substrate, the back substrate, and the first sealing portion. A first exhaust port for exhausting the space, and a second exhaust port for exhausting the space between the first and second sealing portions.

According to another aspect of the present invention, there is provided a method of manufacturing an image display device, comprising: a front substrate and a rear substrate, which are arranged to face each other with a gap and whose peripheral portions are sealed with a sealing material. In the manufacturing method,
A first sealing material is disposed along the peripheral edges of the front substrate and the rear substrate to form a first sealing portion, and the second sealing is cured at a temperature lower than the melting temperature of the first sealing material. An adhesive is disposed outside the first sealing portion to form a second sealing portion, and the second sealing portion is solidified in a state where the front substrate and the rear substrate are opposed to each other. A first exhaust port that seals between the peripheral portions of the rear substrate and communicates with a space defined by the front substrate, the rear substrate, and the first sealing portion, and the first sealing portion and the second sealing portion. The first sealing portion is heated and melted while exhausting the space from the second exhaust port communicating with the space between the front substrate and the peripheral portion of the front substrate and the rear substrate. It is said.

  According to the image display device configured as described above and the manufacturing method thereof, in the sealing step of the front substrate and the rear substrate, the inside of the envelope can be evacuated from a low temperature state, and the electron source characteristics are deteriorated. This makes it possible to manufacture at a relatively low cost.

Hereinafter, a first 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 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 bonded to each other via a rectangular frame-shaped side wall 13 and the inside is maintained in a vacuum state.

  The side wall 13 functioning as a bonding member is sealed to the inner peripheral edge of the back substrate 12 by, for example, a low-melting glass 30 such as frit glass. Between the front substrate 11 and the side wall 13, the 1st sealing layer (1st sealing part) which the base layer 31 formed on the sealing surface and the indium layer 32 formed on this base layer united 33 is sealed. Thereby, the side wall 13 and the 1st sealing layer 33 airtightly join the peripheral parts of the front substrate 11 and the back substrate 12, and prescribe | regulate the sealed space between a front substrate and a back substrate. Further, outside the first sealing layer 33, the peripheral portions of the front substrate and the rear substrate are sealed by a second sealing layer (second sealing portion) 40 made of, for example, silicone. An annular sealed space is formed between the side wall 13 and the first sealing layer 33 and the second sealing layer 40.

  In order to support an atmospheric pressure load applied to the front substrate 11 and the rear substrate 12, for example, a plurality of plate-like support members 14 made of glass are provided inside the vacuum envelope 10. 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.

  In the effective display area, a phosphor screen 16 that functions as a phosphor screen is formed on the inner surface of the front substrate 11. The phosphor screen 16 includes a plurality of phosphor layers 15 that emit red, green, and blue light, and a plurality of light shielding layers 17 formed between the phosphor layers. Each phosphor layer 15 is formed in a stripe shape, a dot shape, or a rectangular shape. On the phosphor screen 16, a metal back 18 and a getter film 19 made of aluminum or the like are sequentially formed.

  In the effective display area, a large number of electron-emitting devices 22 that emit electron beams are provided on the inner surface of the rear substrate 12 as electron sources that excite the phosphor layer 15 of the phosphor screen 16. 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. These electron-emitting devices 22 are arranged in a plurality of columns and a plurality of rows corresponding to each pixel. In addition, a large number of wirings 21 for supplying a potential to the electron-emitting devices 22 are provided in a matrix form on the back substrate 12, and the end portions are drawn out of the vacuum envelope 10.

  Outside the effective display area, at least one first exhaust port 50a and at least one second exhaust port 50b for exhausting the inside of the vacuum envelope 10 are formed on the rear substrate 12. The first exhaust port 50 a communicates with the inner space B <b> 1 defined by the front substrate 11, the rear substrate 12, the side wall 13, and the first sealing layer 33. The second exhaust port 50 b communicates with the side wall 13 and the annular outer space B <b> 2 defined between the first sealing layer 33 and the second sealing layer 40. As shown in FIG. 6, four first exhaust ports 50 a are provided adjacent to the four corners of the side wall 13. Four second exhaust ports 50b are provided adjacent to the four corners of the back substrate 12, respectively. The number and formation position of the first and second exhaust ports 50a and 50b are appropriately selected. As shown in FIG. 2, the first and second exhaust ports 50 a and 50 b are each sealed with a sealing plug 52.

  In the FED configured as described above, a video signal is input to the electron-emitting device 22 and the gate electrode 28. 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. . Since a high voltage is applied to the phosphor screen 16, high strain point glass is used for the plate glass for the front substrate 11, the back substrate 12, the side wall 13, and the support member 14.

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 formed 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 a silicon dioxide film insulating 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, 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. 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 at a predetermined angle with respect to the back substrate surface. Thereafter, for example, molybdenum is deposited as a material for forming the cathode from the direction perpendicular to the surface of the back substrate by an electron beam deposition method. 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.

  The space between the peripheral edge of the back substrate 12 on which the electron-emitting devices 22 are formed and the rectangular frame-shaped side wall 13 is sealed with a low-melting glass 30 in the atmosphere. In addition, the 1st exhaust port 50a and the 2nd exhaust port 50b are formed in the predetermined position of the back substrate 12 previously.

  Subsequently, the back substrate 12 and the front substrate 11 are sealed. In this case, first, the base layer 31 is formed with a predetermined width over the entire circumference on the upper surface of the side wall 13 serving as a sealing surface and the inner peripheral edge of the front substrate 11. For example, a silver paste is used for the base layer 31. The forming method is applied to a necessary portion by a screen printing method. And after air-drying, it formed by drying and baking.

Next, indium, which is a metal sealing material, is applied as a first sealing material on each base layer 31 to form an indium layer 32 extending over the entire circumference of the base layer. Indium is applied, for example, using an ultrasonic iron while applying ultrasonic waves.
As the metal sealing material, it is desirable to use a low-melting-point metal material excellent in adhesion and bonding properties that melts at about 350 ° C. or less. Indium not only has 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. In addition, depending on conditions, the material can be directly bonded to glass without using a base layer, and thus is a material suitable for this embodiment.

  The above-described underlayer 31 is made of 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. In addition to the silver paste described above, a metal paste such as gold, aluminum, nickel, or copper can be used.

  Next, as shown in FIG. 3, a front substrate 11 having a base layer 31 and an indium layer 32 formed on the sealing surface, and a side wall 13 is sealed to the rear substrate 12, and the base layer 31 is formed on the upper surface of the side wall. And the back side assembly in which the indium layer 32 was formed is arrange | positioned in the state in which the sealing surfaces face each other. Thereafter, as the second sealing material, for example, a second sealing layer 40 made of silicone is formed in the gap between the front substrate 11 and the rear substrate 12 outside the side wall 13 where the first sealing material is formed. To do. The type of silicone used for the second sealing layer 40 may be a room temperature curing type or an ultraviolet curing type, but it is desirable to select a heat curing type in consideration of mass productivity. For example, the thermosetting silicone is completely cured under a heating condition of 120 ° C./1 h.

  Then, for example, the second sealing layer 40 is heated and cured at 150 ° C. for a predetermined time, and the peripheral portions of the front substrate 11 and the rear substrate 12 are sealed by the second sealing layer 40.

  As shown in FIG. 3, with the front substrate 11 and the rear substrate 12 facing each other, the position is held by a jig or the like, and is put into a sealing and exhaust device (not shown). In the sealing and exhaust device, first, it is confirmed that the silicone as the second sealing material is cured, and then the exhaust and heating in the envelope are performed. Exhaust is performed through the first and second exhaust pipes 42a and 42b. In the rear substrate 12, a first exhaust port 50a is formed in a non-display area that does not affect the screen inside the side wall 13, and communicates with the inner space B1. Further, in the rear substrate 12, a second exhaust port 50 b is formed outside the side wall 13 and communicates with the outer space B <b> 2 between the side wall 13 and the second sealing layer 40.

  Then, the first and second exhaust pipes 42a and 42b are connected to the rear substrate 12, and communicated with the inside of the envelope 10 through the first exhaust port 50a and the second exhaust port 52b, respectively. The first and second exhaust pipes 42a and 42b are connected to a common exhaust pump 56 via a first electromagnetic valve 54a and a second electromagnetic valve 54b, respectively. In this state, the inside of the envelope is exhausted through the exhaust pipe 42.

  FIG. 4 shows the temperature change of the envelope and the exhaust through the exhaust pipes 42a and 42b. As shown in FIG. 4, first, the exhaust pump 56 is operated with the first solenoid valve 54a opened and the second solenoid valve 54b closed, and the envelope is passed through the first exhaust pipe 42a and the first exhaust port 50a. While the 10 inner space B1 is exhausted (exhaust 1), the envelope is heated.

  Silicone may react with oxygen during heating to decompose and reduce airtightness. Therefore, exhaust and heating in the envelope are performed by placing the envelope in a stable gas environment, for example, in a nitrogen atmosphere whose purity is controlled to 99% or less.

  At the time when evacuation is started, the indium layer 32 on the front substrate 11 side and the indium layer 32 on the side wall 13 side are not sealed to each other, and there is a slight gap. Therefore, the outer space B2 between the outer side of the side wall 13 and the second sealing layer 40 is also exhausted through this gap.

  When the substrate temperature is close to the melting point T of indium, the indium constituting the indium layer 32 is melted and sealed together. At this time, the inside of the indium layer 32 is in a reduced pressure environment, but the space between the indium layer 32 and the second sealing layer 40 is also in a reduced pressure environment. Therefore, the molten indium can be held at a predetermined position without being sucked into the first exhaust port 50a.

When the substrate temperature reaches the melting point T of indium (t1), the second electromagnetic valve 54b is opened, and exhaust of the outer space B2 is started through the second exhaust pipe 42b and the second exhaust port 50b (exhaust 2). When the silicone which comprises the 2nd sealing layer 40 is heated, gas will be discharge | released and it exists in the tendency for the pressure of the outer side space B2 between the side wall 13 and the 2nd sealing layer 40 to become high. Therefore, as described above, the inside of the outer space B2 is exhausted through the second exhaust pipe 42b and the second exhaust port 50b to maintain a reduced pressure environment. The vacuum pressure in the outer space B2 is maintained at 1000 Pa or less. For this purpose, it is desirable that the second sealing layer 40 has good airtightness, that is, it is preferable that there is no leak, and at least the leak amount is 1E + 1 Pa · m ³ / s or less. Then, by maintaining the inner space B1 and the outer space B2 in a reduced pressure environment as described above, the molten indium can be held at a predetermined position without being sucked into the first exhaust port 50a.

The inventor examined the pressure in the inner space B1 and the outer space opposed to each other with the molten sealing layer, for example, the molten indium layer C interposed therebetween, and the presence or absence of breakage in the molten indium layer. The result is shown in FIG. As can be seen from this figure, the pressure in the inner space B1 was maintained at a constant pressure, 1 × 10 ⁻¹ Pa, and the pressure in the outer space B2 was gradually changed. When the pressure P2 in the outer space B2 was 1 × 10 ⁵ Pa or 1 × 10 ⁴ Pa, fracture occurred in the molten indium layer. However, when the pressure P2 was 1 × 10 ³ Pa, 1 × 10 ² Pa, or 0 Pa, the molten indium layer did not break. For this reason, in the exhausting process in the envelope 10, the pressure in the outer space B2 is maintained at 1000 Pa or less, or 10,000 times or less in Pa units with respect to the pressure in the inner space B1.

  Next, after the indium layer 32 is melted, the substrate temperature is further heated to 400 ° C. to perform degassing treatment in the envelope and activation of NEG. Thereafter, the envelope is cooled while the substrate in-plane temperature is uniformly maintained within a range where the substrate is not damaged by the thermal strain stress. Thereby, the indium layer 32 is cured, and the space between the front substrate 11 and the side wall 13 is hermetically sealed by the first sealing layer 33. When the indium layer 32 is cured (t2), the second electromagnetic valve 54b is closed and the exhaust from the second exhaust port 50b is stopped. Then, after the indium layer 32 is solidified, the exhaust pump 56 is stopped when the substrate temperature is lowered to a predetermined cooling temperature, and the exhaust operation is finished. In addition, after exhausting the inside of the envelope 10, the first and second exhaust ports 50 a and 50 b of the back substrate 12 are sealed with a sealing plug 52.

Through the above steps, an FED having the vacuum envelope 10 whose inside is evacuated to a high vacuum is obtained.
According to the FED configured as described above and the manufacturing method thereof, in the heating process in the sealing and exhausting process, since the inside of the envelope is always in a vacuum environment, the characteristics of the electron source are not deteriorated. A high-performance image display device can be obtained. Further, it is possible to manufacture the FED at a relatively low cost without requiring a large vacuum processing apparatus for storing the entire envelope.

  By using indium as the sealing material, it is possible to obtain an envelope having high airtightness and high sealing strength without foaming in a vacuum as in the case of using a frit. 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, the desired position between the front substrate and the side wall can be reliably sealed, and the reliability can be improved.

  The first sealing material constituting the first sealing layer 33 is heated in a state where the inner space B1 defined inside the first sealing layer 33 and the outer space B2 defined outside are maintained in a reduced pressure environment. By melting, the melted sealing material can be held in a predetermined position without being sucked into the first exhaust port and the second exhaust port. Therefore, the desired position between the front substrate and the side wall can be reliably sealed, and the reliability can be improved.

  The first sealing material is not limited to indium but may be any sealing material having a melting temperature of 350 ° C. or lower. For example, a pure metal or alloy containing at least Sn, In, Ga, and Bi may be used. Further, the first sealing material is not limited to a low melting point metal, and low melting point glass such as frit glass can also be used. The second sealing material is not limited to silicone, and a material that cures at a temperature equal to or lower than the temperature at which the first sealing material melts, for example, an inorganic material such as Aron ceramic, polyimide, or an epoxy-based material may be used. If the inorganic material does not react with gas such as oxygen during heating, it is not necessary to place the envelope in a stable gas environment during heating and exhausting, and the envelope may be heated and exhausted in an atmospheric environment. . Although the indium layer is formed on both the front substrate and the side wall, sealing may be performed in a state where the indium layer is formed on only one side. The underlayer may be only one of the front substrate and the side wall, or may be omitted.

  The number of the first and second exhaust ports 50a and 50b formed in the back substrate 12 can be appropriately set according to the size and structure of the display device. The first and second exhaust ports 50 a and 50 b may be provided apart from each other along the circumferential direction of the back substrate 12. As shown in FIG. 7, four first exhaust ports 50a are provided in the vicinity of the central portion of each side of the first sealing layer 33, and four second exhaust ports 50b are respectively provided in the vicinity of the corners of the first sealing layer. It is good also as a provided structure. In addition, as shown in FIG. 8, four first exhaust ports 50 a are provided in the vicinity of four corners of the first sealing layer 33, and four second exhaust ports 50 b are provided on each side of the first sealing layer 33. It is good also as a structure provided in the center part vicinity. When the first and second exhaust ports 50a and 50b are provided by being shifted in the circumferential direction of the back substrate 12, it is advantageous in maintaining the mechanical strength of the envelope. Further, the first exhaust port and the second exhaust port are not limited to the back substrate 12 and can be provided in the front substrate 11.

  Next, an FED and a manufacturing method thereof according to a second embodiment of the present invention will be described. As shown in FIG. 9, according to the second embodiment, both the side wall 13 and the front substrate 11 and between the side wall and the back substrate 12 are indium layers 32 as first sealing portions, respectively. Is sealed by. In this case, the step of forming the frit glass as shown in FIG. 3 can be omitted.

  As shown in FIG. 10, in the FED according to the third embodiment of the present invention, the side wall 13 is made of a metal material and has a circular cross-sectional shape. As the metal material, a metal having a thermal expansion coefficient close to that of the substrate glass, for example, a NiFe alloy was used. Both the side wall 13 and the front substrate 11 and between the side wall and the back substrate 12 are sealed with an indium layer 32 as a first sealing portion.

  In the second and third embodiments described above, other configurations are the same as those of the first embodiment described above, and the same reference numerals are given to the same portions, and detailed descriptions thereof are omitted. In addition, the FEDs according to the second and third embodiments can be manufactured by the same manufacturing method as in the first embodiment.

  The present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

  In the present invention, dimensions, materials, and the like of the side wall and other components are not limited to the above-described embodiment, and can be appropriately selected as necessary. In the above-described embodiment, the inner space and the outer space in the envelope are exhausted by a common pump, but each space may be exhausted separately by an exhaust pump provided separately. The present invention is not limited to an electron source using a field emission electron-emitting device, but an image display device using a pn-type cold cathode device, or another electron source such as a surface conduction type or carbon nanotube, and The present invention can also be applied to other flat-type image display devices whose inside is maintained in a vacuum.

FIG. 1 is a perspective view showing a FED according to a first embodiment of the present invention with a part thereof broken. 2 is a cross-sectional view of the FED, taken along line AA in FIG. FIG. 3 is a cross-sectional view showing a state in which a rear side assembly on which an indium layer and a second sealing layer made of silicone are formed and a front substrate are arranged to face each other in the FED manufacturing process. FIG. 4 is a diagram showing a substrate temperature change and an exhaust process in the heating and sealing processes of the envelope. FIG. 5 is a diagram showing the relationship between the pressures in two spaces located on both sides of the molten sealing layer and the presence or absence of breakage of the sealing layer. FIG. 6 is a plan view of the envelope showing the arrangement positions of the first and second exhaust ports in the FED. FIG. 7 is a plan view of an envelope showing a modification of the arrangement positions of the first and second exhaust ports in the FED. FIG. 8 is a plan view of an envelope showing another modification of the arrangement positions of the first and second exhaust ports in the FED. FIG. 9 is a sectional view showing an FED according to a second embodiment of the present invention. FIG. 10 is a cross-sectional view showing an FED according to a third embodiment of the present invention.

Explanation of symbols

10 ... Vacuum envelope, 11 ... Front substrate, 12 ... Back substrate, 13 ... Side wall,
16 ... phosphor screen, 22 ... electron-emitting device, 31 ... underlayer,
32 ... Indium layer, 33 ... First sealing layer, 40 ... Second sealing layer,
42a ... 1st exhaust pipe, 42b ... 2nd exhaust pipe, 50a ... 1st exhaust port,
50b ... second exhaust port, 52 ... sealing plug, 56 ... exhaust pump, B1 ... inside space,
B2 ... Outer space

Claims (14)

A front substrate and a rear substrate that are arranged to face each other with a gap between them,
A first sealing portion formed of a first sealing material that is provided at a peripheral portion of the front substrate and the rear substrate and seals between the peripheral portions;
A second sealing material that is provided outside the first sealing portion, seals between the peripheral portions of the front substrate and the back substrate, and cures at a temperature lower than the melting temperature of the first sealing material. A second sealing portion formed by:
A first exhaust port for exhausting the space defined by the front substrate, the back substrate and the first sealing portion, and a second exhaust port for exhausting the space between the first and second sealing portions;
An image display device comprising:   The image display device according to claim 1, wherein the first sealing material is a pure metal or an alloy containing at least one of Sn, Bi, Ga, and In. The image display device according to claim 1, wherein the airtightness of the second sealing portion is 1E + 1 Pa · m ³ / s or less.   The image display device according to claim 1, wherein the second sealing material is an organic material or an inorganic material.   The image display device according to claim 4, wherein the organic material includes any one of silicone, polyimide, and an epoxy material.   2. The image display device according to claim 1, wherein a plurality of the first exhaust ports and the second exhaust ports are provided on the back substrate outside the effective display area.   The image display device according to claim 6, wherein the first exhaust port and the second exhaust port are provided to be shifted from each other along a circumferential direction of the back substrate.   The phosphor layer formed on the inner surface of the front substrate, and a plurality of electron-emitting devices that are provided on the rear substrate and emit electrons that excite the phosphor layer. The image display device according to item 1. In the manufacturing method of the image display device including the front substrate and the rear substrate, which are arranged to face each other with a gap and the periphery is sealed with a sealing material,
A first sealing material is disposed along the peripheral edges of the front substrate and the rear substrate to form a first sealing portion, and the second sealing is cured at a temperature lower than the melting temperature of the first sealing material. A second sealing portion is formed by disposing a dressing material outside the first sealing portion;
Solidifying the second sealing portion with the front substrate and the back substrate facing each other, and sealing between the peripheral portions of the front substrate and the back substrate;
The front substrate, the back substrate and the first exhaust port communicating with the space defined by the first sealing portion, and the first exhaust port communicating with the space defined between the first sealing portion and the second sealing portion. A method for manufacturing an image display device, wherein the first sealing portion is heated and melted while exhausting the space from a second exhaust port to seal between the peripheral portions of the front substrate and the rear substrate.   The degree of vacuum in the space between the first sealing portion and the second sealing portion is 1000 Pa or less until the first sealing portion is solidified after the first sealing portion is melted. The method for manufacturing an image display device according to claim 9.   The first sealing portion is solidified after the first sealing portion is melted by heating the first sealing portion while exhausting the space between the front substrate and the rear substrate from the first exhaust port. 11. The method for manufacturing an image display device according to claim 9, wherein the space is exhausted from the first exhaust port and the second exhaust port until.   11. The method for manufacturing an image display device according to claim 9, wherein the first and second sealing materials are cured in a state where the front substrate and the rear substrate are maintained in a stable gas environment.   The method for manufacturing an image display device according to claim 12, wherein the stable gas is N 2 or Ar.   The method for manufacturing an image display device according to claim 12, wherein the purity of the stable gas is 99% or less.

Images