JP3940577B2 - Flat display device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flat display device having a flat shape, and more particularly to a flat display device using a large number of electron-emitting devices.
[0002]
[Prior art]
In recent years, various flat display devices have been developed as next-generation light-weight and thin display devices that replace cathode ray tubes (hereinafter referred to as CRT). 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 referred to as PDP) that emits phosphors by ultraviolet rays of plasma discharge. And a field emission display (hereinafter referred to as FED) that emits a phosphor with an electron beam of a field emission type electron-emitting device.
[0003]
For example, an FED generally has a front substrate and a rear substrate facing each other with a predetermined gap, and these substrates are connected to each other through a rectangular frame-shaped side wall so that their peripheral portions are joined to each other. It constitutes an 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.
[0004]
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 electron beams emitted from a large number of electron-emitting devices, and the phosphors emit light to display an image.
[0005]
In such a display device, the thickness of the display device can be reduced to about several millimeters, and the weight and thickness can be reduced as compared with a CRT currently used as a display of a television or a computer. Can do.
[0006]
[Problems to be solved by the invention]
In the FED 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.
[0007]
As a means for evacuating the envelope, first, the front substrate, the rear substrate, and the side wall, which are the components of the envelope, are bonded by heating in the atmosphere with an appropriate sealing material, and then the front substrate or the rear surface is joined. There is a method of exhausting the inside from an exhaust pipe provided on a substrate and then vacuum-sealing the exhaust pipe. However, a flat envelope has a problem in mass productivity and characteristics because the exhaust speed through the exhaust pipe is extremely slow and the degree of vacuum that can be reached is poor.
[0008]
As a method for solving this problem, for example, Japanese Patent Application Laid-Open No. 2001-229825 discloses a method in which a final assembly of a front substrate and a rear substrate constituting an envelope is performed in a vacuum chamber.
[0009]
Here, first, the front substrate and the rear substrate disposed in the vacuum chamber are sufficiently heated. This is to reduce gas emission from the inner wall of the envelope, which is the main cause of the deterioration of the envelope vacuum. 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 envelope vacuum 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 is dissolved, and cooled until the sealing material is solidified in a state where the front substrate and the rear substrate are combined at a predetermined position.
[0010]
The vacuum envelope created by such a method serves both as a sealing process and a vacuum sealing process, and does not require much time for exhausting the exhaust pipe, and obtains a very good degree of vacuum. be able to.
[0011]
However, in the above method, the sealing process performed in vacuum covers a wide range of heating, alignment, and cooling, and the front substrate and the rear substrate are bonded over a long period of time while the sealing material is dissolved and solidified. Must remain in place. Further, the front substrate and the rear substrate are thermally expanded with heating and cooling at the time of sealing, and the alignment accuracy is likely to deteriorate. Furthermore, there have been problems in productivity and characteristics associated with sealing, such as deterioration of the getter film due to heating during sealing.
[0012]
The present invention has been made in view of the above points, and an object of the present invention is to provide a flat display device that can be easily and reliably sealed in a vacuum atmosphere, and a manufacturing method thereof.
[0013]
[Means for Solving the Problems]
In order to solve the above-described problems, a flat display device according to an aspect of the present invention includes a front substrate and a rear substrate that are arranged to face each other, and a sealing unit that seals the peripheral portions of the front substrate and the rear substrate to each other. The sealing portion includes a rectangular frame-shaped refractory conductive member and a sealing material that constitute a side wall of the envelope, and the refractory conductive member includes It has a melting point higher than that of the sealing material , and each has four or more protruding portions protruding outward from at least one of the front substrate and the rear substrate, and the protruding portion is the high melting point conductive material. And a terminal for energizing the high-melting-point conductive member .
[0014]
Further, a flat display device according to another aspect of the present invention includes an outer surface having a front substrate and a rear substrate arranged to face each other, and a sealing portion that seals the peripheral portions of the front substrate and the rear substrate to each other. An envelope, a phosphor screen formed on the inner surface of the front substrate, and an electron emission source provided on the rear substrate and emitting an electron beam to the phosphor screen to cause the phosphor screen to emit light, The sealing portion includes a rectangular frame-shaped high melting point conductive member that forms a side wall of the envelope and a sealing material, and the high melting point conductive member has a higher melting point than the sealing material. And four or more projecting portions projecting outward from at least one of the front substrate and the rear substrate, and the projecting portions grip the refractory conductive member. And the high melting point conductive part It is characterized by forming a terminal for energizing the.
[0015]
Furthermore, a method of manufacturing a flat display device according to an aspect of the present invention includes a front substrate and a rear substrate which are disposed to face each other, a sealing material and a high melting point conductive member having a melting point higher than that of the sealing material. And a manufacturing method of a flat display device provided with an envelope having a sealing portion that seals the peripheral portions of the back substrate to each other,
A rectangular frame-shaped refractory conductive member having four or more projecting portions projecting outward and constituting the side wall of the envelope is prepared, and the front substrate, the rear substrate, and the refractory conductive member are placed in a vacuum atmosphere. The refractory conductive member is disposed between the front substrate and the rear substrate and positioned with respect to the front substrate and the rear substrate; By disposing a sealing material between the high melting point conductive member and between the back substrate and the high melting point conductive member, and energizing the high melting point conductive member through the protrusion, The sealing material is melted to seal the peripheral portions of the front substrate and the rear substrate together.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments in which a flat display device according to the present invention is applied to an FED will be described in detail with reference to the drawings.
[0017]
As shown in FIGS. 1 to 3, this FED includes a front substrate 11 and a rear substrate 12 each made of rectangular glass as insulating substrates, and these substrates are arranged to face each other with a gap of 1.6 mm. Yes. The size of the rear substrate is slightly larger than that of the front substrate, and a lead-out line (not shown) for inputting a video signal to be described later is formed on the outer periphery of the rear substrate. 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 substantially rectangular plate-shaped side wall 18 and the inside is maintained in a vacuum state. ing.
[0018]
As the side wall 18, a high melting point conductive member having a higher melting point than the sealing material described later and having conductivity, for example, an iron-nickel alloy is used. In addition, as the high melting point conductive member having conductivity, a material containing at least one of Fe, Cr, Ni, and Al is used. As shown in FIGS. 1, 2, and 4, the side wall 18 has projecting portions 18 a, 18 b, 18 c, and 18 d that project outward from the respective corner portions along the diagonal axis direction. The side wall 18 is sealed to the back substrate 12 and the front substrate 11 by, for example, indium or an indium alloy as the sealing material 30.
[0019]
In the sealed state, the protruding portions 18 a, 18 b, 18 c, and 18 d of the side wall 18 protrude outward from the front substrate 11 and extend to the vicinity of the corner of the rear substrate 12. Note that the protrusions 18a, 18b, 18c, and 18d function as terminals for applying a voltage to the side wall 18 and also function as grips when positioning the side wall in the FED manufacturing process, as will be described later. can do.
[0020]
As shown in FIGS. 2 and 3, a plurality of plate-like spacers 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 spacers 14 are arranged in a direction parallel to the short side of the vacuum envelope 10 and are arranged at predetermined intervals along a direction parallel to the long side. The shape of the spacer 14 is not particularly limited to this, and for example, a columnar spacer or the like can be used.
[0021]
A phosphor screen 16 shown in FIG. 5 is formed on the inner surface of the front substrate 11. The phosphor screen 16 is configured by arranging red, green, and blue striped phosphor layers, and a striped black light absorbing layer 20 as a non-light emitting portion located between the phosphor layers. The phosphor layer extends in a direction parallel to the short side of the vacuum envelope, and is arranged at a predetermined interval along a direction parallel to the long side. Note that a metal back layer 17 made of, for example, an aluminum layer is deposited on the phosphor screen 16.
[0022]
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.
[0023]
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. .
[0024]
Next, a method for manufacturing the FED configured as described above will be described in detail. First, an electron-emitting device is formed on a plate glass for a back substrate. In this case, a matrix-like conductive cathode layer 24 is formed on the plate glass, and an insulating film 26 of a silicon dioxide film is formed on the conductive cathode layer by, for example, a thermal oxidation method, a CVD method, or a sputtering method.
[0025]
Thereafter, a metal film for forming a gate electrode such as molybdenum or niobium is formed on the insulating film 26 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.
[0026]
Next, the cavity 25 is formed by etching the insulating film 26 by wet etching or dry etching using the resist pattern and the gate electrode 28 as a mask. Then, after removing the resist pattern, a peeling layer made of, for example, aluminum or nickel is formed on the gate electrode 28 by performing electron beam evaporation from a direction inclined at a predetermined angle with respect to the surface of the back substrate 12. Thereafter, for example, molybdenum is deposited as a material for forming the cathode from the direction perpendicular to the surface of the back substrate 12 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.
Subsequently, the plate-like support member 14 is sealed on the back substrate 12 with low melting point glass.
[0027]
On the other hand, 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, so that the phosphor screen 16 is formed by exposure and development. Next, a metal back layer 17 made of an aluminum film is formed on the phosphor screen 16.
[0028]
As described above, indium is applied as the sealing material 30 to the back substrate 12 to which the support member 14 is sealed, the front substrate 11 on which the phosphor screen 16 is formed, and the sealing surface of the side wall 18. Here, for example, indium is applied to the inner surfaces of the peripheral portions of the back substrate 12 and the front substrate 11. Thereafter, these are put into the vacuum processing apparatus 100 in a state of being opposed to each other with a predetermined gap. For the series of steps described above, for example, a vacuum processing apparatus 100 as shown in FIG. 6 is used.
[0029]
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, which are arranged in order. Have. Each of these chambers is configured as a processing chamber capable of vacuum processing, and all the chambers are evacuated when the FED is manufactured. Adjacent processing chambers are connected by a gate valve or the like.
[0030]
The back substrate 12, the side wall 18, and the front substrate 11 described above are put into the load chamber 101, and after the inside of the load chamber 101 is evacuated, it is sent to the baking and electron beam cleaning chamber 102. In the baking and electron beam cleaning chamber 102, the assembly and the front substrate are heated to a temperature of 350 ° C., and the surface adsorption gas of each member is released.
[0031]
Simultaneously with the heating, an electron beam is applied to the phosphor screen surface of the front substrate 11 and the electron emitting element surface of the rear substrate 12 from an electron beam generator (not shown) attached to the baking and electron beam cleaning chamber 102. Since this electron beam is deflected and scanned by a deflection device mounted outside the electron beam generator, the entire surface of the phosphor screen and the surface of the electron-emitting device can be cleaned with an electron beam.
[0032]
After heating and electron beam cleaning, the assembly and the front substrate are sent to the cooling chamber 103 and cooled to a temperature of about 100 ° C., for example. Subsequently, the assembly and the front substrate are sent to a deposition chamber 104 for forming a getter film, where a Ba film is deposited on the outside of the phosphor screen as a getter film. Since this Ba film can prevent the surface from being contaminated with oxygen, carbon, or the like, the active state can be maintained.
[0033]
Subsequently, the back substrate 12, the side wall 18, and the front substrate 11 are sent to the assembly chamber 105. In the assembly chamber 105, these members are heated to a temperature of about 130 ° C., for example, and the two substrates are overlapped at a predetermined position. At this time, the side walls are held by gripping the protrusions 18a, 18b, 18c, and 18d provided on the side walls 18, and the back substrate 12, the side walls 18, and the front substrate 11 are positioned relative to each other. Further, for example, markings corresponding to the protrusions 18a, 18b, 18c, and 18d of the side wall 18 are provided on the back substrate 12, and the side wall 18 is aligned with the back substrate with high accuracy while monitoring these protrusions and markings. be able to. Since the protrusions 18a, 18b, 18c, and 18d protrude outward from the side wall 18, the side wall 18 can be easily chucked and transported by using these protrusions even in the assembly chamber 105. Can be combined.
[0034]
Subsequently, of the protrusions 18a, 18b, 18c, and 18d of the side wall 18 that is a high melting point conductive member, an electrode is brought into contact with two opposite protrusions, for example, the protrusions 18a and 18c, and a DC current 300A is applied to the side wall 18. For 40 seconds. Then, this current also flows in the indium simultaneously, and the side wall 18 and indium generate heat. Thereby, indium is heated to about 160 to 200 ° C. and melted. At this time, a pressing force of about 50 kgf is applied to the superimposed front substrate 11 and rear substrate 12 from both sides.
[0035]
Thereafter, the energization to the side wall 18 is stopped, and the heat of the sealing region, that is, the side wall 18 and the sealing material 30 is quickly transferred to the surrounding front substrate 11 and back substrate 12 to solidify indium. As a result, the front substrate 11 and the rear substrate 12 are sealed through the side wall 18 and the sealing material 30 to form the vacuum envelope 10. After the energization is stopped, the sealed vacuum envelope 10 is carried out from the assembly chamber 105 in about 60 seconds. The vacuum envelope 10 thus formed is cooled to room temperature in the cooling chamber 106 and taken out from the unload chamber 107.
[0036]
According to the FED configured as described above and the method for manufacturing the FED, by sealing the back substrate 12, the side walls 18, and the front substrate 11 in a vacuum atmosphere, the surface adsorbed gas can be combined with baking and electron beam cleaning. Can be sufficiently released, the getter film is not oxidized, and a sufficient gas adsorption effect can be maintained. Further, a high melting point conductive member such as an iron-nickel alloy is used for the side wall 18 and the side walls 18 are provided even in the vacuum apparatus by providing projecting portions 18a, 18b, 18c, and 18d that can be gripped on the side wall. It becomes possible to easily chuck and convey, and the side wall 18 can be aligned with high precision on the basis of the corner, and can be sealed in a short time.
[0037]
Furthermore, since the high melting point conductive member is energized, when the indium is melted, the non-uniform cross-sectional area of the molten indium becomes large and the indium is disconnected or the glass is prevented from being broken due to local heat generation. It becomes possible. Therefore, the vacuum envelope can be easily and reliably sealed. Further, by sealing the back substrate 12, the front substrate 11, and the side wall 18 with indium, a flat display device without lead can be obtained.
[0038]
In addition, the protrusion part of the high melting-point electroconductive member which comprises a side wall is not restricted to embodiment mentioned above. That is, it is sufficient that four or more protrusions are provided apart from each other, and can be provided at any position, not limited to the corner part of the side wall. As shown in FIG. 7, according to the FED according to the second embodiment of the present invention, the side wall 18 as the high melting point conductive member is formed in a rectangular frame shape and protrudes outward from the center of each side. Projecting portions 18a, 18b, 18c, and 18d. In this case as well, the envelope can be sealed in the same manner as in the first embodiment described above by applying electrodes with the projecting portions 18a and 18c facing each other and applying a direct current. Other configurations are the same as those in the first embodiment.
[0039]
In the first embodiment described above, each protruding portion of the side wall 18 is configured to extend to the vicinity of the corner portion of the back substrate 12, but the FED according to the third embodiment of the present invention shown in FIG. According to the above, the protruding portions 18a, 18b, 18c, and 18d of the side wall 18 extend beyond the periphery of the back substrate 12 to the outside of the back substrate. Other configurations are the same as those of the first embodiment described above, and the same portions are denoted by the same reference numerals and detailed description thereof is omitted. Further, the FED having the above configuration is also manufactured by the same method as that of the first embodiment described above.
[0040]
And according to the third embodiment, it is possible to obtain the same effect as the first embodiment described above, and at the same time, since each protruding portion of the side wall protrudes to the outside of the back substrate, In the manufacturing process, the side walls can be gripped and positioned more easily.
[0041]
In addition, the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. For example, the current flowing through the high melting point conductive member is not limited to direct current, and commercial frequency or high frequency alternating current may be used. Further, the present invention is not limited to a flat display device that requires a vacuum envelope such as an FED, but is also effective for other display devices such as a PDP in which a discharge gas is injected after being evacuated once. As the electron-emitting device, a pn-type cold cathode device or a surface conduction electron-emitting device may be used.
[0042]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to provide a flat display device that can be easily and reliably sealed in a vacuum atmosphere, and a manufacturing method thereof.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an FED according to a first embodiment of the invention.
FIG. 2 is a perspective view showing a state where a front substrate of the FED is removed.
3 is a cross-sectional view taken along line AA in FIG.
FIG. 4 is a plan view showing a side wall of the FED.
FIG. 5 is a plan view showing a phosphor screen of the FED.
FIG. 6 is a diagram schematically showing a vacuum processing apparatus used for manufacturing the FED.
FIG. 7 is a plan view showing a side wall of an FED according to a second embodiment of the present invention.
FIG. 8 is a perspective view showing an FED according to a third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Vacuum envelope 11 ... Front substrate 12 ... Back substrate 14 ... Support member 16 ... Phosphor screen 17 ... Metal back layer 18 ... Side wall 18a, 18b, 18c, 18d ... Projection part 22 ... Electron emission element 30 ... Sealing Material 100 ... Vacuum processing apparatus

Claims (10)

An envelope having a front substrate and a rear substrate arranged to face each other, and a sealing portion that seals the peripheral portions of the front substrate and the rear substrate to each other;
The sealing portion includes a rectangular frame-shaped refractory conductive member and a sealing material that constitute the side wall of the envelope ,
The high melting point conductive member has a melting point higher than that of the sealing material , and has four or more protruding portions that protrude outward from at least one of the front substrate and the rear substrate , The flat display device , wherein the protruding portion forms a grip portion for gripping the refractory conductive member and a terminal for energizing the refractory conductive member . An envelope having a front substrate and a rear substrate disposed opposite to each other, and a sealing portion that seals the peripheral portions of the front substrate and the rear substrate to each other;
A phosphor screen formed on the inner surface of the front substrate;
An electron emission source provided on the back substrate and emitting an electron beam to the phosphor screen to cause the phosphor screen to emit light,
The sealing portion includes a rectangular frame-shaped refractory conductive member and a sealing material that constitute the side wall of the envelope ,
The high melting point conductive member has a melting point higher than that of the sealing material , and has four or more protruding portions that protrude outward from at least one of the front substrate and the rear substrate , The flat display device , wherein the protruding portion forms a grip portion for gripping the refractory conductive member and a terminal for energizing the refractory conductive member .   The flat display device according to claim 1, wherein the protruding portion protrudes from each corner portion of the high melting point conductive member.   The flat display device according to claim 1, wherein the protruding portion protrudes from a substantially central portion of each side of the high melting point conductive member. Flat panel display device according to any one of 4 to claims 1, wherein said sealing material is a conductive material. 6. The flat display device according to claim 5 , wherein the sealing material is indium or an alloy containing indium. The refractory conductive member, Fe, Cr, Ni, flat panel display device according to any one of claims 1, characterized in that it contains at least one of Al 6. A front substrate and a rear substrate disposed opposite to each other; a sealing portion including a sealing material and a high melting point conductive member having a melting point higher than that of the sealing material; and a peripheral portion of the front substrate and the rear substrate sealed together. In a method of manufacturing a flat display device including an envelope having:
Preparing a rectangular frame-shaped high melting point conductive member having four or more projecting portions projecting outward and constituting the side wall of the envelope ;
The front substrate, the rear substrate, and the high melting point conductive member are arranged in a vacuum atmosphere,
The high melting point conductive member is disposed between the peripheral portions of the front substrate and the rear substrate by gripping the protruding portion and positioned with respect to the front substrate and the rear substrate, and the front substrate and the high melting point conductive member. And between each of the back substrate and the high melting point conductive member,
Through the protrusion By energizing the refractory conductive member, thereby melting the sealing material of the flat display device, characterized by sealing together the peripheral portions of the front substrate and the rear substrate Production method. 9. The method for manufacturing a flat display device according to claim 8 , wherein the sealing material is indium or an alloy containing indium. 10. The method for manufacturing a flat display device according to claim 8, wherein the high melting point conductive member contains at least one of Fe, Cr, Ni, and Al.

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