JP2002319346A - Display device and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device and its manufacturing method capable of remarkably reducing hours and facilities required for sealing in assembling an envelope in vacuum and of improving sealing accuracy. SOLUTION: This display device is provided with the envelope having a front substrate 11 and a back substrate 12 oppositely disposed with peripheral edge parts sealed. The sealed part has conductivity and is sealed by sealing members 21a and 21b melted by carrying a current. In the sealing process, after the sealing members are melted by carrying the current to the sealing members attached to the sealed part, the sealed part is sealed by stopping the current-carrying to cool and solidify the sealing members.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat display device, and more particularly, to a display device having a large number of electron-emitting devices inside a vacuum envelope and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, various flat display devices have been developed as next-generation light-weight and thin display devices replacing 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 using the orientation of liquid crystal, and a plasma display panel (hereinafter, PDP) that emits a fluorescent material by ultraviolet rays of plasma discharge. ), A field emission display (hereinafter referred to as FED) in which a phosphor is emitted by an electron beam of a field emission type electron emission element, and a surface conduction electron emission display in which a phosphor is emitted by an electron beam of a surface conduction type electron emission element. (Hereinafter, referred to as SED).

[0003] For example, an FED or SED generally has a front substrate and a rear substrate which are opposed to each other with a predetermined gap therebetween, and these substrates are joined to each other at their peripheral portions via a rectangular frame-like side wall. This constitutes a vacuum envelope. A phosphor screen is formed on the inner surface of the front substrate, and a number of electron-emitting devices (hereinafter, referred to as emitters) are provided on the inner surface of the rear substrate as electron emission sources for exciting the phosphor to emit light. Further, in order to support the atmospheric pressure load applied to the rear substrate and the front substrate, a plurality of support members are disposed between these substrates. The potential on the rear substrate side is almost the ground potential, and the anode voltage Va is applied to the phosphor screen. Then, an image is displayed by irradiating the red, green, and blue phosphors constituting the phosphor screen with an electron beam emitted from the emitter to cause the phosphors to emit light.

[0004] In such an FED or SED, the thickness of the display device can be reduced to about several mm, and it is lighter and thinner than a CRT currently used as a display of a television or a computer. Can be achieved.

[0005]

In the above-mentioned FED and SED, it is necessary to make the inside of the envelope high vacuum. Also, in the case of a PDP, it is necessary to fill the discharge gas with a vacuum once.

As means for evacuating the envelope, first, the front substrate, the rear substrate, and the side walls, which are the constituent members of the envelope, are joined by heating in an atmosphere with a suitable sealing material, and then the front substrate is bonded. Alternatively, there is a method of evacuating the inside through an exhaust pipe provided on the rear substrate and then vacuum-sealing the exhaust pipe. However, in the case of a flat type envelope, the speed of exhausting through an exhaust pipe is extremely low, and the achievable vacuum degree is also low. Therefore, there were problems in terms of mass productivity and characteristics.

As another method, there is a method in which the final assembly of the front substrate and the rear substrate constituting the envelope is performed in a vacuum chamber. In this method, the front substrate and the rear substrate brought into the vacuum chamber are heated sufficiently. This is to reduce the gas emission from the inner wall of the envelope, which is a main cause of deteriorating the degree of vacuum of the envelope. Next, when the front substrate and the rear substrate are cooled and the degree of vacuum in the vacuum chamber is sufficiently improved, a getter film for improving and maintaining the degree of vacuum of the envelope is formed on the phosphor screen. Thereafter, the front substrate and the rear substrate are heated again to a temperature at which the sealing material dissolves, and the front substrate and the rear substrate are combined with each other at a predetermined position and cooled until the sealing material is solidified.

[0008] The vacuum envelope produced by such a method serves not only as a sealing step but also as a vacuum sealing step, does not require much time associated with exhausting the exhaust pipe, and is extremely good. A degree of vacuum can be obtained.

However, in the case of assembling in such a vacuum, the processing performed in the sealing step includes heating, positioning, and cooling, and the sealing material melts and solidifies for a long time. The substrate and the back substrate must be kept in place. In addition, there is a problem in productivity and characteristics associated with sealing, such as that the front substrate and the rear substrate are thermally expanded due to heating and cooling at the time of sealing, and the alignment accuracy is likely to deteriorate.

The present invention has been made in view of the above points, and has as its object to greatly reduce the time and equipment required for sealing when assembling an envelope in a vacuum, and to improve sealing accuracy. And a method of manufacturing the same.

[0011]

In order to achieve the above object, a display device and a method of manufacturing the same according to the present invention provide an outer enclosure having a front substrate and a rear substrate which are opposed to each other and whose peripheral edges are sealed. And a sealing portion located between the front substrate and the rear substrate, wherein the sealing portion has conductivity and is sealed by a sealing member which is melted by energization. That is, by applying a current to the sealing member provided at the sealing portion, the sealing member is melted and sealed.

According to the display device and the method of manufacturing the same as described above, only the sealing member is mainly heated and melted by the heat generated by the current flowing through the conductive sealing member. Then, by stopping the current supply immediately after the sealing member is melted, the heat of the sealing member is quickly diffused and transmitted to the front substrate and the rear substrate and solidified by cooling. This eliminates the need for a heating device for heating the entire front substrate and the rear substrate in the sealing step, and further significantly reduces the time required for the sealing step. Also,
The thermal expansion of the front substrate and the rear substrate is extremely small,
When these are sealed, the deterioration of positional accuracy can be improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment in which a 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 to 3, this FE
D includes a front substrate 11 and a rear substrate 12 each made of rectangular glass as an insulating substrate, and these substrates are opposed to each other with a gap of 1 to 2 mm. The front substrate 11 and the rear substrate 12 are joined to each other via a rectangular frame-shaped side wall 13 to form a flat rectangular vacuum envelope 10 in which the inside is maintained in a vacuum state. .

In the present embodiment, the front substrate 11 and the side wall 13 are made of a conductive sealing member 21a,
1b, the back substrate 12 and the side wall 13 are joined by a low melting point sealing member 40 such as frit glass.

Inside the vacuum envelope 10, a front substrate 11 is provided.
And to support the atmospheric pressure load applied to the rear substrate 12,
A plurality of plate-shaped spacers 14 are provided. These spacers 14 are arranged in a direction parallel to the long side of the vacuum envelope 10 and at predetermined intervals along a direction parallel to the short side. The spacer 14
Is not particularly limited, and for example, a columnar spacer or the like can be used.

On the inner surface of the front substrate 11, a phosphor screen 15 having a red, green, and blue phosphor layer 16 and a matrix-like black light absorbing layer 17 as shown in FIG. 4 is formed. An aluminum film (not shown) is deposited as a metal back on the phosphor screen.

On the inner surface of the back substrate 12, a phosphor layer 16
Many electron-emitting devices 18 are provided as electron-emitting sources for exciting the electrons. The electron-emitting devices 18 are arranged at positions facing the respective phosphor layers 16 and emit electron beams toward the corresponding phosphor layers.

Next, a method of manufacturing the FED configured as described above will be described. As shown in FIGS. 5 and 6, the phosphor screen 15 is formed on the inner surface of the front substrate 11 before the assembly. Further, on the inner surface of the front substrate 11, a metal solder having conductivity is filled in a rectangular frame shape as a sealing member 21 a outside the phosphor screen 15, and is disposed along the periphery of the front substrate 11. Electrodes 22a and 22b for energizing the sealing member at the time of sealing are formed to protrude outward at two opposite corners of the sealing member 21a.

The cross-sectional area of each of the electrode portions 22a and 22b is formed larger than the cross-sectional area of other portions of the sealing member 21.

On the other hand, a large number of electron-emitting devices 18 are previously formed on the inner surface of the rear substrate 12, and the side walls 13 and the spacers 14 are sealed with a low melting point to secure a gap with the front substrate 11 during assembly. The attachment member 40 is attached. On the side wall 13, a metal solder having conductivity as the sealing member 21b is filled in a rectangular frame shape at a position facing the sealing member 21a on the front substrate 11 side.

The front substrate 11 and the rear substrate 12 as described above are assembled in a vacuum chamber along the steps shown in FIG. That is, first, the front substrate 11 and the rear substrate 12
Is introduced into a vacuum chamber, the inside of the vacuum layer is evacuated, and then the front substrate 11 and the rear substrate 12 are sufficiently degassed by heating. The heating temperature is appropriately set at about 200 ° C. to 500 ° C. This is to reduce the rate of gas release from the inner wall, which deteriorates the degree of vacuum after the vacuum envelope is formed, and to prevent characteristic deterioration due to residual gas.

Next, a getter film is formed on the phosphor screen 15 of the front substrate 11 which has been degassed and cooled.
This is because the residual gas after forming the vacuum envelope is adsorbed and exhausted by the getter film, and the degree of vacuum in the vacuum envelope is maintained at a favorable level.

Finally, the phosphor layer 16 and the electron-emitting device 18
The front substrate 11 and the rear substrate 12 are superimposed on each other at predetermined positions such that they face each other. In this state, power is supplied to the sealing members 21a and 21b via the electrode portions 22a and 22b, and the sealing members are heated and melted. Thereafter, the power supply is stopped, and the heat of the sealing members 21a and 21b is quickly diffused and conducted to the front substrate 11 and the side wall 13, so that the sealing member 21
a, 21b are solidified. Thereby, the sealing member 21
The front substrate 11 and the side wall 13 are sealed with each other by a and 21b.

Next, each component of the manufacturing apparatus and the FED used in the above-mentioned sealing step will be described. As shown in FIG. 8, before the sealing, the temperatures of the front substrate 11 and the rear substrate 12 are set to be lower than the melting points of the sealing members 21a, 21b.
Is in a solidified state. In this state, the front substrate 11 and the rear substrate 12 are overlapped at a predetermined position, and the sealing members 21a and 21b also overlap each other. A predetermined sealing load is applied to the front substrate 11 and the rear substrate 12 in directions approaching each other by the pressing devices 23a and 23b. The image display area is held in a predetermined gap by the spacer 14, and the sealing members 21a and 21b are also in contact with each other. Further, power supply terminals 24a and 24b are in contact with the electrode portions 22a and 22b of the sealing member 21a, respectively, and these power supply terminals 24a and 24b are connected to a power supply 25.

In this state, when a predetermined current is supplied to the sealing members 21a and 21b through the power supply terminals 24a and 24b, only the sealing members 21a and 21b generate heat and melt. Thereafter, when energization is stopped, the sealing member 21 having a small heat capacity is used.
The heat of a and 21b is radiated to front substrate 11 and side wall 13 by the temperature gradient, reaches thermal equilibrium with front substrate 11 and side wall 13 having a large heat capacity, and is quickly cooled and solidified.

According to such a method, the vacuum envelope can be vacuum sealed with a very short and simple manufacturing apparatus. In other words, by using a sealing member having conductivity, it is possible to selectively heat only the sealing member having a small heat capacity without heating the substrate, that is, a small volume, without heating the substrate. Deterioration of accuracy and the like can be suppressed.

Further, since the heat capacity of the sealing member is much smaller than the heat capacity of the substrate, the time required for heating and cooling can be greatly reduced as compared with the conventional method of heating the entire substrate, and the mass productivity can be reduced. It can be greatly improved. Furthermore, the only device required for sealing is a mere power supply terminal and a mechanism for bringing it into contact.This is a very simple and clean device suitable for ultra-high vacuum, not only for the conventional full-surface heater but also for the electromagnetic induction heating method. Can be realized.

As the form of the current to be supplied, not only a DC current but also an AC current fluctuating at a commercial frequency may be used. In this case, the trouble of converting the commercial current transmitted by the alternating current into the direct current can be omitted, and the apparatus can be simplified. Further, an alternating current that fluctuates at a high frequency of the kHz level may be used. In this case, since the Joule heat increases by an amount corresponding to the increase in the effective resistance value to the high frequency due to the skin effect, the same heating effect as described above can be obtained with a smaller current value.

The power to be supplied and the time are set to about 5 to 300 seconds in this embodiment. If the energization time is long (small power), the cooling rate decreases due to a rise in temperature around the substrate and adverse effects occur due to thermal expansion. If the energization time is short (high power), the filling of the conductive sealing material becomes uneven. Breakage due to disconnection or thermal stress of glass occurs. Therefore, it is necessary to set optimal conditions for the power to be energized and the time (including a temporal power change) for each object.

The temperature difference between the substrate temperature at the time of sealing and the melting point of the sealing member is about 20 ° C. to 150 ° C. in the embodiment. When the temperature difference is large, the cooling time can be shortened, but the thermal stress of the glass becomes large. Therefore, it is necessary to set optimum conditions for each object.

The stress and strain caused by the temperature difference between the front and back surfaces of the substrate due to thermal diffusion conduction from the sealing member are as follows.
As shown in FIG. 9, the stress can be reduced by making the outer diameters of the pressurizing devices 23a and 23b slightly smaller than the outer diameter of the substrate and naturally bending the periphery of the substrate as shown by a broken line. Alternatively, even when the outer diameters of the pressurizing devices 23a and 23b are not reduced, a similar effect of countermeasures against stress can be obtained by providing a shaved portion serving as a relief when the substrate is warped around the pressurizing device. .

Further, in the above-described embodiment, the vacuum envelope having the structure in which the side wall is sandwiched between the front substrate and the rear substrate is used, but the structure in which the side wall is integrated with the front substrate or the rear substrate may be employed. Alternatively, the side wall may be joined so as to cover the front substrate and the rear substrate from the side. Furthermore,
The sealing surfaces to be sealed by energization heating of the sealing member may be two surfaces between the front substrate and the side wall and between the rear substrate and the side wall.

In the above-described embodiment, the heating is performed by bringing the sealing member on the front substrate side into contact with the sealing member on the rear substrate side, but the heating is performed without contacting these sealing members. After that, they may be joined until they are solidified. The configuration of the phosphor screen and the configuration of the electron-emitting device are not limited to the embodiments of the present invention, and may be other configurations. The sealing member may be filled with only one of the two surfaces to be sealed.

In some cases, a base of the conductive sealing material is formed for the purpose of ensuring the wettability of the conductive sealing material with respect to the substrate. However, such a base itself becomes a main heat source having conductivity. Is also good.

The present invention is not limited to a display device requiring a vacuum envelope such as an FED or an SED, but is also applicable to other display devices such as a PDP in which a discharge gas is injected after a vacuum is applied once. It is valid.

Hereinafter, a plurality of embodiments will be described. (Embodiment 1) An embodiment in which the front substrate 11 and the rear substrate 12 shown in FIGS. 5 and 6 are applied to a 36-inch TV FED display device will be described. The main configuration is the same as that described in the above embodiment.

The front substrate 11 and the rear substrate 12 are both made of a glass material having a thickness of 2.8 mm, and the side walls 13 have a thickness of 1.1 mm.
Of glass material. Sealing members 21a, 2a filled in the side walls 13 of the front substrate 11 and the rear substrate 12;
1b uses In which melts at about 160 ° C. and has a width of 3 to 5 m.
m, and filled to a thickness of 0.1 to 0.3 mm on one side. Electrode part 2
2a and 22b are provided at two diagonal target locations where interference with the X wiring and Y wiring of the opposing rear substrate 12 is small,
To reduce the risk of disconnection during energization, the cross-sectional area is increased to about 16 mm in width and 0.1 to 0.3 mm in thickness. The resistance between the electrode portions 22a and 22b is 0.1 to 0.5 at room temperature.
It is about 5Ω.

The front substrate 11 and the rear substrate 12 are
After degassing in a vacuum chamber and forming a getter film, the pressure device 23
a, 23b. And, as shown in FIG.
The front substrate 11 and the rear substrate 12 are arranged at predetermined positions at a temperature of about 100 ° C., and are superposed with a load of about 50 kg by the pressurizing devices 23a and 23b.
a and 24b are connected to the electrode portions 21a and 21b.

In this state, a direct current of 120 A is applied for 100 seconds to sufficiently dissolve the sealing members 21a and 21b over the entire circumference. After stopping the energization, the front substrate 1 and the rear substrate 1
2 was held for 60 seconds to dissipate the heat of the sealing members 21a and 21b whose temperature was increased by energizing heating to the front substrate 11 and the side wall 13, thereby solidifying the sealing members 21a and 21b.

When the vacuum envelope is manufactured in this manner, the time required for sealing is conventionally reduced from about 30 minutes to about several minutes, and the apparatus for sealing is simplified. We were able to.

(Embodiment 2) The main configuration of Embodiment 2 is the same as that of Embodiment 1. In the second embodiment, in the above-described sealing process, the effective current value 1 fluctuating at 60 Hz which is the commercial frequency is used.
A sine wave AC current of 50 A was applied to the sealing members 21a and 21b for 40 seconds, and then held for 30 seconds to form a vacuum envelope.

(Embodiment 3) The main configuration of Embodiment 3 is the same as that of Embodiment 1. In Example 3, in the sealing step,
A sine wave alternating current having an effective current value of 4 A, which fluctuates at a frequency higher than the commercial frequency, for example, 300 kHz, was applied to the sealing members 21a and 21b for 30 seconds, and then held for 30 seconds to form a vacuum envelope. .

(Embodiment 4) The main configuration of Embodiment 4 is the same as that of Embodiment 1. In Example 4, FIGS. 10 and 11
As shown in FIG. 7, in addition to the above-described bonding between the front substrate 11 and the side wall 13, the bonding between the rear substrate 12 and the side wall 13 was performed in a vacuum chamber using a sealing member having conductivity. Here, a rectangular frame-shaped sealing member 26 and electrode portions 27a and 27b protruding outward from diagonal corners of the sealing member are provided on a portion of the front substrate 11 facing the side wall 13, and a back substrate is provided. A sealing member 28 in the form of a rectangular frame and electrode portions 29a and 29b protruding outward from diagonal corners of the sealing member are provided on a portion of the sealing member 12 facing the side wall 13.

The front substrate 11, the rear substrate 12, and the side wall 13 are superimposed on the predetermined positions as described above, and 100 A is supplied from the power source 31 to the electrode portions 27a, 27b via the power supply terminals 30a, 30b for 150 seconds. At the same time, 100 A was supplied from the power source 33 to the electrode portions 29a and 29b via the power supply terminals 32a and 32b for 150 seconds. Thereafter, the front substrate 11, the rear substrate 12, and the side walls 13 were sealed by solidifying the sealing members 26 and 28 while holding them for about 2 minutes.

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 pair of electrode portions provided on the sealing member may be provided at symmetrical positions, and is not limited to the pair of diagonal portions of the sealing portion member, and may be provided on each long side or short side. good.
Further, the sealing member having conductivity is not limited to In, but may be an alloy containing In.

[0046]

As described above in detail, according to the present invention, only the sealing portion can be instantaneously heated with a simpler device, and the sealing member can be instantaneously cooled due to heat conduction and heat capacity. It is possible to provide a flat display device which can be solidified, and at the same time, has a small temperature change of the whole substrate at the time of sealing, improves sealing accuracy, and has excellent characteristics and productivity, and a method for manufacturing the same. .

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing the internal configuration of the FED.

FIG. 3 is a sectional view taken along line AA of FIG. 1;

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

FIG. 5 is a plan view showing a front substrate used for manufacturing the FED.

FIG. 6 is a plan view showing a back substrate, side walls, and spacers used for manufacturing the FED.

FIG. 7 is a flowchart showing a flow of assembly in a vacuum chamber in the manufacturing process of the FED.

FIG. 8 is a cross-sectional view showing a step of sealing the entire substrate and the side wall in the above manufacturing process.

FIG. 9 is a view for explaining a method for alleviating a glass stress generated at the time of sealing an FED according to an embodiment of the present invention.

FIG. 10 is a plan view showing components of an FED according to a second embodiment of the present invention.

FIG. 11 is a plan view showing a sealing step in the second embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 ... Front board 12 ... Back board 13 ... Side wall 14 ... Spacer 15 ... Phosphor screen 18 ... Electron emission element 21a, 21b, 26, 28 ... Sealing member 22a, 22b, 27a, 27b, 29a, 29b ... Electrode part 24a , 24b, 30a, 30b, 32a, 32b ... power supply terminals

 ────────────────────────────────────────────────── ─── 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 BD02 PP08 5C032 AA01 BB16 BB18 5C036 EE14 EE19 EF01 EF06 EF09 EG02 EG06 EG31 EH04

Claims (22)

[Claims] An enclosure having a front substrate and a rear substrate which are opposed to each other and whose peripheral edges are sealed is provided, wherein the sealing portion located between the front substrate and the rear substrate is electrically conductive. And a sealing device that is sealed by a sealing member that melts when energized. 2. The package according to claim 1, wherein the envelope has a frame-shaped side wall located between peripheral edges of the front substrate and the rear substrate, and the sealing member includes at least one of the front substrate and the rear substrate and the side wall. The display device according to claim 1, wherein the display device is provided on a joint surface between the display device and the display device. 3. The sealing member is provided in a frame shape along a sealing portion on a peripheral edge of the envelope, and has two electrode portions protruding outward from the sealing portion. The display device according to claim 1, wherein: 4. The display device according to claim 3, wherein a cross-sectional area of each of said electrode portions is larger than a cross-sectional area of another portion of said sealing member. 5. The display device according to claim 3, wherein the two electrode portions are provided at symmetrical positions with respect to a peripheral portion of the envelope. 6. The display device according to claim 1, wherein the sealing member contains In or an alloy containing In. 7. The device according to claim 1, wherein an electron source and a phosphor are provided inside the envelope, and the interior of the envelope is maintained at a vacuum. The display device according to claim 1. 8. A method of manufacturing a display device comprising an envelope having a front substrate and a rear substrate which are opposed to each other and whose peripheral portions are sealed, wherein a sealing between the peripheral portions of the front substrate and the rear substrate is performed. A method for manufacturing a display device, comprising: providing a sealing member having conductivity along a sealing portion, and energizing and melting the sealing member to seal the sealing portion. 9. A frame-like side wall is arranged between peripheral portions of the front substrate and the rear substrate, and the sealing member is provided on a joint surface between at least one of the front substrate and the rear substrate and the side wall, 9. The method for manufacturing a display device according to claim 8, wherein a current is applied to the sealing member to melt the sealing member. 10. The method according to claim 8, wherein a direct current is applied to the sealing member. 11. The method for manufacturing a display device according to claim 8, wherein an alternating current having a commercial frequency is supplied to said sealing member. 12. The method according to claim 8, wherein an AC current having a frequency higher than a commercial frequency is supplied to the sealing member from an AC current supply source. 13. The sealing member according to claim 8, wherein In or an alloy containing In is used.
13. The method for manufacturing a display device according to claim 1. 14. The conductive member is provided in the form of a frame along a sealed portion at the periphery of the envelope, and the conductive member is formed with two electrode portions projecting outward from the sealed portion. The method for manufacturing a display device according to claim 8, wherein the conductive member is energized through the portion. 15. The method of manufacturing a display device according to claim 14, wherein an electric area of each of said electrode portions is formed larger than a cross-sectional area of another portion of said sealing member. 16. The method according to claim 14, wherein the two electrode portions are provided symmetrically with respect to a peripheral edge of the envelope. 17. The method according to claim 8, wherein the temperature of the front substrate and the rear substrate immediately before energizing the sealing member is set lower than the melting point of the sealing member. 6. The method for manufacturing a display device according to claim 1. 18. The method according to claim 1, wherein the difference between the temperature of the front substrate and the rear substrate immediately before energizing the sealing member and the melting point of the sealing member is in the range of 20 ° C. to 150 ° C. 18. The method for manufacturing a display device according to item 17. 19. An electric current is supplied to said sealing member while said envelope is maintained in a vacuum atmosphere.
19. The method for manufacturing a display device according to any one of items 18 to 18. 20. The method according to claim 20, wherein the front substrate and the rear substrate are heated and degassed in a vacuum atmosphere, and then cooled to a temperature lower than the melting point of the sealing member while maintaining the vacuum atmosphere. To heat and melt only the sealing member, to stop energizing the sealing member, and to conduct heat of the sealing member to the front substrate and the rear substrate to cool and solidify the sealing member. 20. The method according to claim 19, wherein the envelope is sealed in a vacuum. 21. When energizing the sealing member, mechanical constraint on the peripheral portion of the front substrate or the rear substrate is eliminated.
21. The method for manufacturing a display device according to claim 20, wherein the sealing is performed while allowing the peripheral portion to be bent by heat. 22. The method according to claim 19, wherein the peripheral portion is sealed with the electron source and the phosphor provided inside the envelope, and the inside of the envelope is maintained at a vacuum. 2
2. The method for manufacturing a display device according to claim 1.