JP2005251476A - Method for manufacturing image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing image display device which can perform sealing operation with rapidity and stability. <P>SOLUTION: Sealing layers 21a, 21b are formed on the peripheries of a front substrate 11 and a back substrate 12 respectively, the front substrate 11 is disposed opposite to the Back substrate 12, and then a current passage is formed through the sealing layers 21a, 21b to start feeding current. After a lapse of a current increasing term which is 10% or more of the total current-feeding time, a current to a maximum current value is fed during a specified time. The current-feeding heats and melts the sealing layers 21a, 21b, and the peripheries of the front substrate 11 and the back substrate 12 bond to each other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a manufacturing method for manufacturing a flat-type image display device including a pair of substrates that are arranged to face each other and whose peripheral portions are sealed to each other.

  2. Description of the Related Art In recent years, various image display devices have been developed as next-generation lightweight and thin display devices that replace cathode ray tubes (hereinafter referred to as CRTs). Such image 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 referred to as PDP) that emits phosphors by ultraviolet rays of plasma discharge. A field emission display (hereinafter referred to as FED) that emits a phosphor by an electron beam of a field emission electron emission device; a surface conduction electron emission display (hereinafter referred to as SED) that emits a phosphor by an electron beam of a surface conduction electron emission device; Etc.).

  Among these various display devices, for example, FEDs and SEDs generally have a front substrate and a rear substrate arranged to face each other with a predetermined gap, and these substrates are connected to each other through a rectangular frame-shaped side wall. Are joined together to form a vacuum envelope. 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.

  Further, in order to support an atmospheric pressure load applied to the back substrate and the front substrate, a plurality of support members are disposed between these substrates. The potential on the back substrate side is almost the ground potential, and an anode voltage 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.

  For example, in the FED as described above, various manufacturing methods have been studied in order to join the front substrate and the rear substrate constituting the envelope. In general, a sintered material such as frit glass is filled between two substrates and side walls, heated and sintered in a furnace, and the substrate and side walls are bonded to form an envelope. As an example of a basic procedure, a material in which a side wall is welded to a rear substrate is prepared in advance, and this and the front substrate are further welded.

However, unnecessary gas is generated when the frit glass is sintered. This gas remains inside the sealed envelope after welding and becomes an obstacle when the inside of the envelope is exhausted to a high vacuum later. Therefore, a low melting point metal sealing material such as indium that melts at a relatively low temperature is filled between the front substrate and the side wall, and the conductive sealing material itself is heated by the Joule heat when the conductive sealing material is energized. A method of dissolving and bonding substrates (hereinafter referred to as energization heating) has been studied.
JP 2002-319346 A

  In the above-mentioned current heating, it is necessary to supply a current so that the conductive sealing material is stably melted. If it is not melted stably, the time required for melting the conductive sealing material differs depending on the envelope, and stable substrate bonding cannot be performed. If the conductive sealing material is heated too much, the heat causes a problem that the conductive sealing material is disconnected or a substrate is cracked. On the other hand, if the substrate is not sufficiently dissolved, bonding of the substrates becomes insufficient, resulting in problems such as deterioration in vacuum tightness and inability to maintain the vacuum state of the envelope. For this reason, conventionally, a 100 A direct current was supplied to the entire conductive sealing material, and heating and melting were performed in about 1 minute. As a result, the conductive sealing material could be stably melted, but cooling took 10 to 20 minutes. For this reason, further shortening of the sealing time has been desired for the purpose of improving mass productivity.

  At this time, it is possible to shorten the time required for dissolution and cooling of the conductive sealing material by increasing the constant current value. However, when the current value is increased, between the conductive sealing material and the electrode, There has been a problem that sparks are frequently generated between the electrode contacts on the device side or between the sealing layers, and the sealing layer cannot be stably dissolved.

  The present invention has been made in view of the above points, and an object thereof is to provide a method of manufacturing an image display device capable of quickly and stably performing a sealing operation of a conductive sealing material. .

  In order to achieve the above object, the present invention provides a method of manufacturing an image display device including an envelope having a front substrate and a back substrate, and at least one peripheral portion of the front substrate and the back substrate has conductivity. The sealing material is arranged to form a sealing layer, the front substrate and the rear substrate are arranged to face each other, a current path is formed in the sealing layer, and energization to the sealing layer is started, and the entire energization time A current that reaches a maximum current value after a current rising period of 10% or more of the current is energized for a predetermined time, and the sealing layer is heated and melted by the energization to bond the peripheral portions of the front substrate and the back substrate to each other. Features.

  In order to achieve the above object, the present invention provides a method of manufacturing an image display device including an envelope having a front substrate and a rear substrate, and at least one peripheral portion of the front substrate and the rear substrate is made conductive. A sealing layer is formed by disposing a sealing material, and a pair of electrodes for supplying power for heating and melting the sealing layer is attached to the sealing layer, and the power source is attached to the sealing layer. Current path is formed, the front substrate and the back substrate are arranged to face each other, the front substrate and the back substrate are pressurized in a direction approaching each other, and in the pressurized state, to the sealing layer via the electrode Energization is started, a current that reaches a maximum current value is passed through a current increase period of 10% or more of the entire energization time for a predetermined time, and the sealing layer is heated and melted by the energization, whereby the front substrate and the back substrate Around each other Characterized in that it focus.

  Furthermore, in order to achieve the above object, the present invention provides a method for manufacturing an image display device including an envelope having a front substrate and a rear substrate that are arranged opposite to each other and whose peripheral portions are joined to each other. A sealing material having conductivity is disposed on each peripheral portion of the opposite surfaces of the back substrate, and a sealing layer is formed on each of the front substrate and the back substrate, the sealing layer of the front substrate, and A pair of electrodes for supplying power for heating and melting the sealing layer is attached to the sealing layer of the back substrate, respectively, and the power source of the power source is attached to the sealing layer of the front substrate and the sealing layer of the back substrate, respectively. Forming a current path, starting energization to the sealing layer through the electrode, energizing a current reaching a maximum current value through a current rising period of 10% or more of the entire energization time for a predetermined time, and After the surface substrate sealing layer and the back substrate sealing layer are heated and melted, the front substrate and the back substrate are pressed in a direction approaching each other with the front substrate and the back substrate facing each other. The peripheral portions of the front substrate and the back substrate are bonded to each other.

  According to the method of manufacturing an image display device configured as described above, a gradual slope that reaches the maximum current value after a current rising period of 10% or more of the entire energization time is applied to the conductive sealing material. By energizing a current with a predetermined time and heating and sealing the above-mentioned sealing material, the maximum current value for heating and melting was set to be more than twice the current, and the heating energization time was shortened Even in this case, it is possible to reliably avoid the occurrence of sparks and to supply a stable current to the sealing layer. As a result, the sealing layer can be formed to have a uniform thickness over the entire circumference, and the sealing operation can be performed stably in a short time while maintaining the entire substrate at a low temperature.

  ADVANTAGE OF THE INVENTION According to this invention, the sealing method can be performed stably and rapidly, and the manufacturing method which can manufacture an image display apparatus with high reliability and high display quality can be provided.

Hereinafter, an embodiment in which an image display device according to the present invention is applied to an FED will be described in detail with reference to the drawings.
As shown in FIGS. 1 to 4, the FED includes a front substrate 11 and a rear substrate 12 each made of a rectangular glass plate, and these substrates are arranged to face each other with a gap of 1 to 2 mm. The back substrate 12 is formed to have a size larger than that of the front substrate 11. The front substrate 11 and the back substrate 12 constitute a flat rectangular vacuum envelope 10 whose peripheral portions are joined to each other via a rectangular frame-shaped side wall 18 and the inside is maintained in a vacuum state. .
A plurality of plate-like support members 14 are provided inside the vacuum envelope 10 in order to support an atmospheric pressure load applied to the front substrate 11 and the rear substrate 12. These support members 14 extend in a direction parallel to one side of the vacuum envelope 10 and are arranged at predetermined intervals along a direction orthogonal to the one side. The support member 14 is not limited to a plate shape, and a columnar member may be used.

  A phosphor screen 16 that functions as an image display surface is formed on the inner surface of the front substrate 11. The phosphor screen 16 is configured by arranging red, green, and blue phosphor layers R, G, and B, and a black light absorbing layer 20 positioned between these phosphor layers. The phosphor layers R, G, and B extend in a direction parallel to the one side of the vacuum envelope 10 and are arranged at a predetermined interval along a direction orthogonal to the one side. On the phosphor screen 16, for example, a metal back 17 made of aluminum and a getter film 27 made of barium are sequentially stacked.

  As shown in FIG. 3, on the inner surface of the back substrate 12, a large number of electron-emitting devices 22 that emit electron beams are provided as electron-emitting sources that excite the phosphor layer of the phosphor screen 16. 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 back substrate 12, and a silicon dioxide film 26 having a large 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. Further, on the inner surface of the back substrate 12, a large number of wirings 23 for supplying a potential to the electron-emitting devices 22 are provided in a matrix shape, and the end portions are drawn out to the peripheral edge portion of the vacuum envelope 10.

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

  Thus, since a high voltage is applied to the phosphor screen 16, a high strain point glass is used as the plate glass for the front substrate 11, the back substrate 12, the side wall 18, and the support member 14. As will be described later, the back substrate 12 and the side wall 18 are sealed with a low melting point glass 19 such as frit glass. Further, the front substrate 11 and the side wall 18 are sealed by a sealing layer 21 containing indium (In) as a conductive low melting point sealing material.

  The FED includes a plurality of, for example, a pair of electrodes 30, and these electrodes are attached to the envelope 10 in a state of being electrically connected to the sealing layer 21. These electrodes 30 are used as electrodes when energizing the sealing layer 21.

  As shown in FIG. 5, each electrode 30 is formed by bending, for example, a 0.2 mm thick copper plate as a conductive member. That is, the electrode 30 is bent so that the cross section is substantially U-shaped, and is positioned at the mounting portion 32, the body portion 34 that extends from the mounting portion and serves as a current path for the sealing layer, and the extension end of the body portion. A contact portion 36 that can come into contact with the sealing layer, and a flat conductive portion 38 formed by the mounting portion and the back portion of the body portion are integrally provided. The mounting portion 32 is integrally provided with a holding portion bent into a clip shape, and can be attached by holding the peripheral portion of the front substrate 11 or the back substrate 12. The contact portion 36 is formed with a horizontal extension length L of 2 mm or more. The body portion 34 is formed in a belt shape and extends obliquely upward from the mounting portion 32. Thereby, the contact part 36 is located higher than the mounting part 32 and the trunk | drum 34 along the vertical direction.

  As shown in FIGS. 1 to 3, each electrode 30 is attached in a state of being elastically engaged with, for example, the back substrate 12 of the vacuum envelope 10. That is, the electrode 30 is attached to the vacuum envelope 10 in a state where the peripheral portion of the back substrate 12 is elastically held by the mounting portion 32. The contact portions 36 of each electrode 30 are in contact with the sealing layer 21 and are electrically connected. The body portion 34 extends from the contact portion 36 to the outside of the vacuum envelope 10, and the conducting portion 38 is exposed to the outer surface of the vacuum envelope 10 so as to face the side surface of the back substrate 12. The pair of electrodes 30 are provided at two corners of the vacuum envelope 10 that are separated in the diagonal direction, and are arranged symmetrically with respect to the sealing layer 21.

Next, the manufacturing method of FED which has the said structure is demonstrated 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 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. In this state, the phosphor screen is formed on the glass plate which becomes the front substrate 11 by exposing and developing. Thereafter, a metal back 17 is formed on the phosphor screen 16.

  Subsequently, the electron-emitting device 22 is formed on the plate glass for the back substrate 12. In this method, a matrix-like conductive cathode layer 24 is formed on a plate glass, and an insulating film of a silicon dioxide film is formed on the 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.

  Thereafter, the insulating film is etched by wet etching or dry etching using the resist pattern and the gate electrode 28 as a mask to form the cavity 25. Then, after removing the resist pattern, a peeling layer made of, for example, aluminum or nickel is formed on the gate electrode 28 by performing electron beam evaporation from a direction inclined by a predetermined angle with respect to the surface of the back substrate 12. Further, for example, molybdenum is deposited by electron beam evaporation as a material for forming the cathode from a direction perpendicular to the surface of the back substrate 12. As a result, the electron-emitting device 22 is formed inside the cavity 25. Next, the release layer is removed together with the metal film formed thereon by a lift-off method.

  Subsequently, the side wall 18 and the support member 14 are sealed on the inner surface of the back substrate 12 by the low melting point glass 19 in the atmosphere. Next, as shown in FIGS. 6A and 6B, indium is applied to a predetermined width and thickness over the entire circumference of the sealing surface of the side wall 18 to form a sealing layer 21a. Indium is applied to a predetermined width and thickness over the entire circumference of the sealing surface of the front substrate 11 facing the adhesion surface to form the sealing layer 21b. The filling of the sealing layers 21a and 21b to the sealing surfaces of the side walls 18 and the front substrate 11 is a method of applying molten indium to the sealing surface, or a method of placing solid indium on the sealing surface. Etc.

  Subsequently, as shown in FIG. 7, the pair of electrodes 30 is mounted on the back substrate 12 to which the side walls 18 are bonded. At this time, each electrode 30 is mounted in a state in which the contact portion 36 does not contact the sealing layer 21a and faces the sealing layer with a gap. The electrode 30 requires a pair of a positive electrode and a negative electrode on the substrate, and it is desirable that the energization paths of the sealing layers 21a and 21b energized in parallel between the pair of electrodes have the same length. Therefore, the pair of electrodes 30 are attached to two corners facing the diagonal direction of the back substrate 12, and the lengths of the sealing layers 21a and 21b located between the electrodes are set to be approximately equal on both sides of each electrode. Has been.

  After the electrode 30 is mounted, the rear substrate 12 and the front substrate 11 are arranged to face each other with a predetermined distance therebetween, and in this state, they are put into a vacuum processing apparatus. Here, for example, a vacuum processing apparatus 100 shown in FIG. 8 is used. The vacuum processing apparatus 100 includes a load chamber 101, baking, an electron beam cleaning chamber 102, a cooling chamber 103, a getter film deposition chamber 104, an assembly chamber 105, a cooling chamber 106, and an unload chamber 107 arranged side by side. ing. Connected to the assembly chamber 105 are a power supply device 120 that outputs a DC power supply for heating and melting the sealing layers 21 a and 21 b, and a computer 200 that controls the power supply device 120. Each chamber of the vacuum processing apparatus 100 is configured as a processing chamber capable of vacuum processing, and all the chambers are evacuated when the FED is manufactured. These processing chambers are connected by a gate valve or the like (not shown).

  First, the front substrate 11 and the rear substrate 12 that are opposed to each other with a predetermined distance are put into the load chamber 101. Then, after the atmosphere in the load chamber 101 is changed to a vacuum atmosphere, it is sent to the baking and electron beam cleaning chamber 102.

  In the baking and electron beam cleaning chamber 102, various members are heated to a temperature of 350 to 400 ° C. to release the surface adsorption gas of each substrate. At the same time, an electron beam is irradiated onto the phosphor screen surface of the front substrate 11 and the electron-emitting device surface of the rear substrate 12 from an electron beam generator (not shown) attached to the baking and electron beam cleaning chamber 102. At that time, the electron beam is deflected and scanned by a deflection device mounted outside the electron beam generator, whereby the entire surfaces of the phosphor screen surface and the electron-emitting device surface are respectively cleaned with the electron beam.

  In the baking step, the sealing layers 21a and 21b are once melted by heating to have fluidity, but the contact portions 36 of the electrodes 30 face each other with no gap between them without contacting the sealing layers 21a and 21b. ing. Therefore, it is possible to suppress the molten indium from flowing out of the back substrate 12 through the electrode 30.

  The front substrate 11 and the rear substrate 12 that have been subjected to baking and electron beam cleaning are sent to a cooling chamber 103, cooled to a temperature of about 120 ° C., and then sent to a getter film deposition chamber 104. In the vapor deposition chamber 104, a barium film is deposited on the outside of the metal back 17 as the getter film 27. The barium film can prevent the surface from being contaminated with oxygen, carbon, or the like, and can maintain an active state.

  Subsequently, the front substrate 11 and the rear substrate 12 are sent to the assembly chamber 105. As shown in FIG. 9, in the assembly chamber 105, the front substrate 11 and the rear substrate 12 are respectively held by hot plates 131 and 132 in the assembly chamber in a state of being opposed to each other. The front substrate 11 is fixed to the upper hot plate 131 by the fixing jig 133 so as not to fall.

  Thereafter, the front substrate 11 and the rear substrate 12 are moved in directions approaching each other while being maintained at about 120 ° C., and are pressurized with a predetermined pressure. The substrate may be moved either by moving both the front substrate 11 and the back substrate 12 so as to approach each other, or by moving either one of the front substrate and the back substrate so as to approach each other.

  By pressurizing at a predetermined pressure in this way, the sealing layer 21b on the front substrate 11 side and the sealing layer 21a on the rear substrate 12 side are brought into contact with each other, and the contact portions 36 of the respective electrodes 30 are connected to the sealing layer 21a. , 21b, and each electrode 30 is electrically connected to the sealing layers 21a, 21b. At this time, since the contact portion 36 is formed with a horizontal length of 2 mm or more, the contact portion 36 can stably contact the sealing layers 21a and 21b. In addition, by applying indium to the contact portion 36 of the electrode 30 in advance, a better contact and energized state can be obtained with respect to the sealing layer.

  In this state, as shown in FIG. 10, after electrically connecting the power output terminals of the power supply device 120 to the pair of electrodes 30, the sealing layer 21 a on the side wall 18 side and the front substrate 11 side from the power supply device 120. A direct current is applied to each of the sealing layers 21b in a constant current mode, and the energization heats the sealing layers 21a and 21b to melt indium.

  In the embodiment according to the present invention, at the time of heating and melting by energizing the sealing layers 21a and 21b, the maximum current value (constant current value) passes through a current rising period of 10% or more of the entire energizing time in the energizing transition period. A current having a gradual slope reaching a maximum current value of 200 amperes is applied for a predetermined time to heat and melt the sealing layers 21a and 21b.

  The heat-melting process by energizing the sealing layers 21a and 21b at this time will be described with reference to FIG. The power supply device 120 generates a predetermined constant current power source of about 200 to 400 amperes, for example, in the constant current source 121. The power output controller 122 controls the output of the constant current generated by the constant current source 121 and has a transient current control function. Here, according to the control command (or the pressurization state detection signal of the substrate pressurization mechanism in the assembly chamber 105) CS output from the computer 200, as shown in the figure, the current rise period is 10% or more of the entire energization time. After that, a current (Io) having a gradual slope reaching a maximum current value (constant current period) and having a maximum current value of 200 amperes or more is output for a predetermined time. Current paths flowing through the sealing layers 21a and 21b at this time are indicated by symbols ia and ib in the drawing. In the application example of the sealing layer in the above embodiment, since the sealing layer 21b is applied to the front substrate 11 and the sealing layer 21a is applied to the rear substrate 12, the output current is determined by the sealing layer. The ia and ib flowing through 21a and the ia and ib flowing through the sealing layer 21b are divided into four. Therefore, for example, when the maximum current value (Io) is 280 amperes, constant currents of 70 amperes respectively flow through the sealing layer 21a as ia and ib uniformly during the constant current period (tb).

  In the embodiment of the present invention, the current value required for heating and melting is set higher by gradually increasing the output current value during the energization transition period up to the maximum current value (Io). The occurrence of the above spark is avoided.

  Examples of various current waveforms in the energization transition period (current rise period) up to the maximum current value (Io) at this time are shown in FIG. FIG. 6A shows the transient current (TI) in the current rise period (ta) that is the energization transition period until the maximum current value (Io), that is, the constant current period (tb). It is changed in a straight line. The energization transition period (ta), which is the current increase period, is set to 10% or more of the entire energization time (ta + tb), and output control of the transient current is performed by the output control unit 122 according to the setting. In FIG. 5B, the current rise period (ta), which is the energization transition period up to the maximum current value (Io), is set to 50% or more, and the transient current (TI) is changed in a curve in the engine. Yes. FIG. 6C shows that the transient current (TI) is changed to an s-shaped curve during the current rise period (ta), which is the energization transition period up to the maximum current value (Io). FIG. 4D shows that the transient current (TI) is changed stepwise in the current rise period (ta) that is the energization transition period up to the maximum current value (Io).

  FIG. 13 and FIG. 14 show examples of power supply in various heating and melting treatment modes that reach a predetermined constant current through the current rising period as described above. FIG. 13 shows an example of supplying the constant current power source in the pressure-heating mode in which the sealing layers 21a and 21b are heated and melted in a state where the substrates (the front substrate 11 and the rear substrate 12) are pressurized. In this case, the sealing layers 21a and 21b are heated and melted by supplying the current by the above-mentioned equal flow from a single power source under the pressurized state. FIG. 14 shows heating in which the substrates (front substrate 11 and back substrate 12) are pressed against each other in a state where the sealing layer 21b applied to the front substrate 11 and the sealing layer 21a applied to the back substrate 12 are heated and melted, respectively. An example of supplying the constant current power source in the pressurizing mode is shown. In this case, the sealing layers 21a and 21b are heated and melted simultaneously in parallel by separate power sources or single power sources.

  As described above, in the assembly chamber 105, at the time of heating and melting by energizing the sealing layers 21a and 21b applied to the front substrate 11 side and the back substrate 12 side, 10% or more of the entire energization time is exceeded. A current having a gradual slope reaching a maximum current value after a current rising period is applied for a predetermined time, and the sealing layers 21a and 21b are heated and melted to heat and melt the sealing layer. The peripheral edge of the front substrate 11 and the side wall 18 are sealed by 21.

The front substrate 11, the side wall 18, and the rear substrate 12 sealed by the above process are cooled to room temperature in the cooling chamber 106 and taken out from the unload chamber 107. Thereby, the vacuum envelope 10 of the FED is completed.
In addition, after the vacuum envelope 10 is completed, the pair of electrodes 30 may be removed if necessary.

  According to the FED manufacturing method as described above, a current that is 10% or more of the entire energization time during heating and melting by energizing the sealing layers 21a and 21b applied to the front substrate 11 side and the back substrate 12 side. The sealing layer 21a, 21b is heated and melted by applying a current having a maximum slope of 200 amperes or more with a gentle slope that reaches the maximum current value after a rising period, and the sealing layers 21a and 21b are heated and melted. By sealing the peripheral edge portion of the front substrate 11 and the side wall 18 with the layer 21, the time required for the sealing operation in the above-described processing step can be shortened, and problems such as sparks can be avoided and the sealing layer 21 can be avoided. An electric current for stable heating and melting can be passed. Therefore, the sealing work can be performed in a short time before the entire substrate is heated unnecessarily, and the sealing work can be performed efficiently and quickly. Furthermore, since the conductive low-melting-point sealing material constituting the sealing layer can be stably and reliably melted in a predetermined energization time, the sealing layer 21 can be promptly and reliably not cracked. Sealing can be performed.

  From the above, an FED that is excellent in mass productivity and at the same time capable of obtaining a stable and good image can be manufactured at low cost.

  In the above-described embodiment, the current increase control at the initial energization is not limited to the example shown in FIG. 11 to FIG. 14. In short, the current path is formed in the sealing layer to the sealing layer. Various modifications and applications are possible in the method of starting energization and energizing the current that reaches the maximum current value through a current increase period of 10% or more of the entire energization time for a predetermined time. In addition, although the mounting portion of the electrode 30 is integrally provided with a clip-shaped clamping portion, as shown in FIGS. 15 and 16, it may be configured with a separate clip 41 that functions as a clamping portion. That is, the electrode 30 has a contact portion 36, a body portion 34, and a flat base portion 39, which are integrally formed by bending a plate material. In addition, the mounting portion of the electrode 30 includes a base portion 39 and a separate clip 41. The electrode 30 is attached to the back substrate 12 by sandwiching the base portion 39 and the peripheral portion of the substrate, here the peripheral portion of the back substrate 12 with the clip 41.

  In addition, the present invention is not limited to the above-described embodiment as it is, 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.

  Further, in the above-described embodiment, the sealing layer made of indium is provided on both the back substrate side and the front substrate side. However, in the state where the sealing layer is provided only on either one, It is good also as a structure which seals a back substrate.

  The sealing material is not limited to indium, and other materials may be used as long as the sealing material has conductivity. In general, when a metal changes in phase, a sudden change in resistance value occurs, so that it can be used as a sealing material. For example, a metal containing at least one of In, Sn, Pb, Ga, and Bi can be used as the sealing material.

Further, the side wall of the envelope may be integrally formed with the rear substrate or the front substrate in advance. Needless to say, the outer shape of the vacuum envelope and the structure of the support member are not limited to the above embodiment, and further, a matrix type black light absorption layer and a phosphor layer are formed, and the cross section is a cross shape It is good also as a structure which positions and seals this columnar support member with respect to a black light absorption layer. As the electron-emitting device, a pn-type cold cathode device or a surface conduction electron-emitting device may be used. In the above embodiment, the step of bonding the substrates in a vacuum atmosphere has been described. However, the present invention can also be applied in other atmospheric environments.
The present invention is not limited to the FED, but can also be applied to other image display devices such as SEDs and PDPs, or image display devices in which the inside of the envelope does not become a high vacuum.

The perspective view which shows the whole FED which concerns on embodiment of this invention. The perspective view which shows the internal structure of the said FED. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. The top view which expands and shows a part of phosphor screen of the FED. The perspective view which shows the electrode of the said FED. The top view which each shows the front substrate and back substrate which are used for manufacture of the said FED. The perspective view which shows the state which attached the electrode to the back substrate of the said FED. The figure which shows schematically the vacuum processing apparatus used for manufacture of the said FED. Sectional drawing which shows the state which has arrange | positioned the back substrate and front substrate in which indium was arrange | positioned facing. The top view which shows typically the state which connected the power supply to the electrode of FED in the manufacturing process of the said FED. The figure for demonstrating the electric current control means in the time of the heat-melting by the electricity supply to a sealing layer in the manufacturing process of the said FED. The figure which shows the various electric current waveforms applicable at the time of the said heat-melting. The figure which shows the example of supply of the constant current power supply in the pressurization-heating mode in the manufacturing process of the said FED. The figure which shows the example of supply of the constant current power supply in the heating-pressurization mode in the manufacturing process of the said FED. The perspective view which shows the other structural example of the electrode applied to this invention. Sectional drawing which shows the state which mounted | wore with the electrode shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Vacuum envelope, 11 ... Front substrate, 12 ... Back substrate, 14 ... Supporting member, 16 ... Phosphor screen, 18 ... Side wall, 21, 21a, 21b ... Sealing layer, 22 ... Electron emission element, 30 ... Electrode 32... Mounting portion 34. Body portion 36. Contact portion 38. Conduction portion 100. Vacuum processing device 120. Power source device 121. Constant current source 122.

Claims (8)

In a method for manufacturing an image display device including an envelope having a front substrate and a rear substrate,
On the peripheral edge of at least one of the front substrate and the back substrate, a conductive sealing material is disposed to form a sealing layer,
The front substrate and the rear substrate are arranged opposite to each other,
Forming a current path in the sealing layer to start energization to the sealing layer, energizing a current that reaches a maximum current value through a current rising period of 10% or more of the entire energization time for a predetermined time;
A method for manufacturing an image display device, wherein the sealing layer is heated and melted by the energization to bond the peripheral portions of the front substrate and the back substrate together. In a method for manufacturing an image display device including an envelope having a front substrate and a rear substrate,
On the peripheral edge of at least one of the front substrate and the back substrate, a conductive sealing material is disposed to form a sealing layer,
A pair of electrodes for supplying power for heating and melting the sealing layer is attached to the sealing layer, and a current path for the power source is formed in the sealing layer.
The front substrate and the back substrate are arranged opposite to each other, and the front substrate and the back substrate are pressed in a direction approaching each other,
Start energization to the sealing layer through the electrode in the pressurized state,
A current that reaches the maximum current value after a current rising period of 10% or more of the entire energization time is energized for a predetermined time,
A method for manufacturing an image display device, wherein the sealing layer is heated and melted by the energization to bond the peripheral portions of the front substrate and the back substrate together. In a manufacturing method of an image display device including an envelope having a front substrate and a rear substrate, which are disposed opposite to each other and have peripheral portions bonded to each other,
A sealing material having conductivity is disposed on each of the peripheral portions of the front substrate and the back substrate facing each other, and a sealing layer is formed on each of the front substrate and the back substrate,
A pair of electrodes for supplying power for heating and melting the sealing layer is attached to the sealing layer of the front substrate and the sealing layer of the rear substrate, respectively, and the sealing layer of the front substrate and the rear substrate are attached. Forming a current path for the power source in each sealing layer,
Starting energization to the sealing layer through the electrode, energizing a current reaching a maximum current value through a current rising period of 10% or more of the entire energization time for a predetermined time,
After heating and melting the sealing layer of the front substrate and the sealing layer of the rear substrate by the energization,
Pressurizing the front substrate and the back substrate in a direction approaching each other with the front substrate and the back substrate facing each other,
A manufacturing method of an image display device, wherein peripheral portions of the front substrate and the back substrate are bonded to each other. 3. The method for manufacturing an image display device according to claim 1, wherein the sealing layer is heated and melted at a current of a maximum current value of 200 amperes or more. 4. The method for manufacturing an image display device according to claim 3, wherein each of the sealing layers is heated and melted at a maximum current value of 100 amperes or more. 4. The method of manufacturing an image display device according to claim 1, further comprising: current control means capable of varying the current rising period up to 100% so that the current rising period can be arbitrarily set. 3. The method for manufacturing an image display device according to claim 1, wherein a pair of electrodes for supplying a power source for heating and melting the sealing layer is disposed so as to be in contact with the sealing layer at two opposing positions on the periphery of the substrate. A pair of electrodes for heating and melting the sealing layer of the front substrate and a pair of electrodes for heating and melting the sealing layer of the rear substrate are respectively positioned at two opposing positions on the periphery of the corresponding substrate. The method of manufacturing an image display device according to claim 3, wherein the image display device is arranged different from the two positions.

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