JPH11162333A - Manufacture of fluorescent character display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture more easily the electron emission part of a fluorescent character display device. SOLUTION: A cathode body structure 106 is formed by arranging fixedly a needle-shaped columnar graphite (emitter) with a length of several millimeters comprising an aggregate of carbon nano tube on an electrode 106b, in the range of about 3 mm ϕ on the upper surface in advance, as electron emission parts, and by arranging the electrode 106b in the center on a ceramic substrate 106a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a fluorescent display device utilizing light emission of a phosphor by the impact of an electron beam.

[0002]

2. Description of the Related Art In a fluorescent display device, electrons emitted from an electron emission portion are contained in a vacuum vessel at least one of which is transparent.
This is an electron tube that emits light by colliding with a phosphor to emit light, and uses the emitted light. Usually, the fluorescent display device having a triode structure provided with a grid for controlling the function of electrons is most often used. Conventionally, a cathode called a filament is used for the electron emission portion, and thermions emitted from the cathode collide with the phosphor to emit light. Among such fluorescent display devices, there is an image tube that constitutes a pixel of a large screen display device.

Hereinafter, the picture tube will be described with reference to FIG. First, a brief description will be given. In a cylindrical glass bulb 301, a fluorescent screen 304, an anode electrode assembly 305, and a cathode assembly 306 constituting an electron emission section are arranged. Then, a face glass 302 having translucency is bonded and fixed to the opening end of the cylindrical glass bulb 301 with a low melting point frit glass 303. Then, the inside of the glass bulb 301 is evacuated by evacuating from the exhaust pipe 308a formed integrally with the stem glass 308 of the glass bulb 301.

[0004] Among them, the face glass 302 is
A convex lens-shaped spherical portion 302a is formed on the front side, and a flange-shaped step portion 302b is formed on the peripheral edge. Further, on the main surface of the inner surface 302c, a phosphor screen 304 and an Al metal back film 307 are sequentially laminated and formed. In addition, one end of a contact piece 307a having an elastic force and formed by processing a thin plate of, for example, stainless steel by a press molding method is inserted into a peripheral portion of the inner surface 302c of the face glass 302. Further, the contact piece 307a is brought into contact with the Al metal back film 307 and adhered and fixed to a predetermined portion of the inner surface 302c of the face glass 302 by, for example, a conductive adhesive made of a mixture of carbon or silver and frit glass. The other end of the contact piece 307a is extended toward the inner wall surface of the glass bulb 301.

On the other hand, stem pins 309a to 309 are attached to stem glass 308 forming the bottom of glass bulb 301.
e is inserted. On the stem glass 308, the anode lead 31 is attached to the tip of the lead pin 309a.
0 is fixed by welding, and a cylindrical anode electrode assembly 305 is fixedly arranged and mounted on the tip of the anode lead 310 by welding. The anode electrode assembly 305 is formed by, for example, a ring-shaped anode 305a formed by rolling a stainless steel metal wire into a ring shape, and a rectangular stainless steel thin plate wound around the outer peripheral surface of the ring-shaped anode 305a. And a cylindrical anode 305b fixed at two points by welding or the like to form a cylindrical shape.

The anode electrode assembly 305 is welded to a tip of the anode lead 310 at a predetermined position with a ring-shaped anode 305a. It is fixed by welding at the contact part. Further, this ring-shaped anode 305a
, A Ba getter 305c is attached and fixed by welding or the like.

The cathode pins 311b to 311e are fixed to the tips of the lead pins 309b to 309e by welding, and the cathode assembly 306 is fixed to the tips of the cathode leads 311b to 311e by welding. . The cathode structure 306 is formed as follows. First, the back electrode 306b is arranged and fixed at the center on the ceramic substrate 306a. Next, at a predetermined interval above the filament cathode 30
6c is fixed by two columns. Then, an elliptical grid housing 306d having a mesh portion 306e is mounted on the ceramic substrate 306a so as to cover them. Note that the mesh part 306e is
A shape protruding spherically in the direction of 4 is set.

In the picture tube formed as described above, first, a voltage (heating power source) is supplied to the lead pins 309c and 309d from an external circuit, so that the cathode leads 311 are provided.
A predetermined electric potential is applied to the filament cathode 306c via c and 311d, so that thermoelectrons are emitted.
Further, by supplying a voltage to the lead pin 309b from an external circuit, the back electrode 3 is connected via the cathode lead 311b.
At 06b, a negative potential is applied to the filament cathode 306c. In addition, lead pins 309
By applying a voltage to e, a positive potential is applied to the filament cathode 306c to the grid housing 306d via the cathode lead 311e, so that an electron beam is emitted from the mesh portion 306e of the grid housing 306d.

Then, lead pins 309a are supplied from an external circuit.
To the anode lead 310 → the anode electrode assembly 3
05 (cylindrical anode 305b) → Electric electrons are accelerated by the cylindrical anode 305b by conducting the respective paths of the contact pieces 307a to make the high voltage applied to the Al metal back film 307, Al metal back film 3
07 and penetrates the fluorescent screen 304. As a result, the phosphor screen 304 is excited by the electron impact, and the phosphor screen 30 is excited.
The emission color corresponding to the phosphor constituting the face glass 3
02, light is displayed on the front side.

[0010]

By the way, the filament (filament cathode) as an electron emitting portion used in the conventional fluorescent display device has a diameter of 7 to 20 μm.
An electron-emitting material is applied to a thin tungsten wire of m. The electron-emitting material is generally made of a so-called ternary oxide of barium oxide / calcium oxide / strontium oxide. Here, these oxides are extremely unstable in air.
For this reason, in the production of the filament, in the form of a so-called carbonate of barium carbonate, calcium carbonate, and strontium carbonate, a tungsten thin wire is applied so as to have an outer shape of 22 to 35 μm. After assembling together with each part, the inside of the envelope is evacuated and oxidized at the stage of aging.

Therefore, in the conventional fluorescent display device, since the above-described filament is used as the electron emitting portion, there are the following problems. That is, there is a problem that handling is inconvenient and difficult to manufacture because a very thin and fragile filament must be stretched and assembled. Further, as described above, the number of steps was very large in order to produce a filament cathode.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to make it easier to manufacture an electron emitting portion of a fluorescent display device.

[0013]

According to a method of manufacturing a fluorescent display device of the present invention, an electron emission portion is formed of a carbon nanotube formed of a cylindrical graphite layer, and a tip portion thereof is arranged toward a fluorescent screen side. Then, an emitter from which electrons are emitted from the tip and an electron extraction electrode for extracting electrons from the emitter arranged on the electron emission side of the emitter are provided. Since it is manufactured in this manner, a field emission type cold cathode electron source can be constituted by the emitter and the electron extraction electrode.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a configuration of an image tube which is a fluorescent display device according to an embodiment of the present invention. Hereinafter, the configuration of the picture tube according to this embodiment will be described together with the manufacturing method thereof. First, in a cylindrical glass bulb 101, a fluorescent screen 104, an anode electrode assembly 105, and a cathode constituting an electron emission section The structure 106 is arranged. Further, a face glass 102 is bonded and fixed to the opening end of the glass bulb 101 with a low melting point frit glass 103. And the glass bulb 10
A stem glass 108 is arranged at the bottom of the glass bulb 101, and the inside of the glass bulb 101 is evacuated by evacuating the exhaust from an exhaust pipe 108a integrally formed with the stem glass 108.

First, the face glass 102 has a convex lens-shaped spherical portion 102a formed on the front surface side and a flange-shaped step portion 102b formed on the peripheral edge portion. On the inner surface 102c of the face glass 102, as shown in FIG. 1 (b), a concave portion 102d is formed in a part of the peripheral portion thereof. Also, a fluorescent screen 104 is formed on the main surface of the inner surface 102c, and an Al metal back film 107 is formed on the surface of the fluorescent screen 104. Note that the fluorescent screen 104 is not formed in the recess 102d, and the Al metal back film 107 is not formed.
Only to form. One end of a contact piece 107a having an elastic force and formed by processing a thin plate of, for example, a stainless steel material by a press molding method is inserted into the recess 102d. The contact piece 107a is formed by bonding and fixing to the concave portion 102d with a conductive adhesive material 10 made of, for example, a mixture of carbon or silver and frit glass. The other end of the contact piece 107a extends toward the inner wall surface of the glass bulb 101.

The phosphor screen 104 has a thickness of about 20 μm as a white phosphor, for example, a paste obtained by dissolving a Y ₂ O ₂ S: Tb + Y ₂ O ₃ : Eu mixed phosphor in a solvent and adding a binder thereto. Now, print and apply to the inner surface 102c,
This is formed by drying. Here, the recess 102d
The fluorescent screen 104 is not applied inside. Incidentally, the phosphor used _{is, Y 2 O 2 S: Tb} + Y 2 O 3: not limited to Eu phosphor mixture, it is needless to say that may be used other phosphors. Also, the fluorescent screen 10
On the surface of the Al metal back film 107, an aluminum film is formed to a thickness of about 150 nm by vapor deposition.
To form Here, the phosphor screen 104 is provided in the recess 102d.
Is not applied, so that only the Al metal back film 107 is formed.

If the thickness of the Al metal back film 107 is too small, the number of pinholes increases and the reflection of the phosphor screen 104 decreases. On the other hand, if the thickness is too large, the penetration of the electrons of the electron beam into the phosphor screen 104 is inhibited, and the light emission decreases. Therefore, the Al metal back film 10
Control of the thickness of 7 is important. Therefore, as described above, the Al metal back film 107 has a thickness of about 15
It is better to be about 0 nm. The fluorescent screen 104
After the formation of the Al metal back film 107, the face glass 102 is heated at 560.degree.
Baking in air for about 0 minutes to remove the solvents in the coating film.

The face glass 102 has, for example, a flange-like shape formed on the periphery of the face glass 102 at one open end of the glass bulb 101 having both ends cut at a diameter of about 20 mm and a length of about 50 mm. Step portion 102b
At the portion, the glass is adhered and fixed with the low melting point frit glass 103. In this method, a low-melting frit glass paste is applied to the bonding surface, and the stepped portion 102b of the face glass 102 and the opening end of the glass bulb 101 are brought into contact with each other via the low-melting frit glass paste. do it.

On the other hand, a lead pin 109 is inserted through the stem glass 108 at the bottom of the glass bulb 101. An anode lead 110 is fixed to the tip of the lead pin 109 by welding.
A cylindrical anode electrode assembly (electron accelerating electrode) 1
05 is fixedly arranged by welding. This anode electrode structure 10
Explaining the formation of 5, first, a ring-shaped anode 105a is formed by, for example, rounding a stainless steel wire (diameter of about 0.5 mm) into a ring shape. Then, a rectangular stainless steel thin plate (having a thickness of 0.01 to 0.02 mm) is wound around the outer peripheral surface of the ring-shaped anode 105a,
The overlapped portion is defined as the welding point 105d and the welding point 105e.
Weld and fix in several places. Thus, the cylindrical anode 105b can be formed in a cylindrical shape.

The anode electrode assembly 105 is welded to a tip of the anode lead 110 at a predetermined position with a ring-shaped anode 105a. Weld and fix at the contact area of. Further, a Ba getter 105c is fixed to a part of the ring-shaped anode 105a by welding or the like. In FIG. 1A, the anode electrode assembly 10
No cross section is shown for 5 and the lead pin 109.

Also, lead pins 109a and 109b are inserted through the stem glass 108, and the lead pins 109a and 109b are inserted.
The cathode leads 111a, 11a
1b is fixed by welding.
The cathode structure 106 is fixedly disposed at the distal end of the a and 111b by welding. This cathode structure 106 is formed as follows. First, an electrode (conductive plate) 106b is arranged at the center on the ceramic substrate 106a. On the upper surface, as shown in an enlarged view in FIG. 1B, a needle-shaped columnar graphite (emitter) 121 having a length of several mm made of an aggregate of carbon nanotubes is arranged in a region of about 3 mmφ in the longitudinal direction. Are fixedly arranged substantially in the direction of the fluorescent screen 104.

The columnar graphite 121 is fixedly arranged with a conductive adhesive 122. This fixing, for example,
The columnar graphite 121 is disposed on the electrode 106b via the conductive adhesive 122, the solvent of the conductive adhesive 122 is volatilized, and then heated in air to about 40 to 600 ° C. for about 15 to 60 minutes. And baking. As described above, by performing the firing in an atmosphere in which oxygen is present, the carbon powder attached to the columnar graphite 121 as a by-product in the manufacturing process can be burned off. If the carbon powder remains, it may be scattered due to vibration or the like, which may cause adverse effects. This firing may be performed, for example, in an atmosphere evacuated to about 1 to 10 ^-3 Torr.

Here, the production of the electrode 106b on which the columnar graphite 121 as the electron-emitting component is formed in the first embodiment will be described in more detail. First,
By processing the metal plate, as shown in FIG. 2A, a plate-shaped portion 201 having a predetermined shape is connected to the frame 201a in a lead frame shape. Next, as shown in FIG. 2B, a conductive adhesive 202 is applied and formed on a predetermined region of the surface of the shape portion 201. Next, the columnar graphite 203 is arranged and fixed on the conductive adhesive 202 such that its longitudinal direction is perpendicular to the plane of the shape portion 201. This fixing may be performed by firing as described above.

Next, as shown in FIG. 2D, a shape portion 201 on which the columnar graphite 203 is formed is cut out from the frame 201a. Then, by bending both ends 201b of the shape portion 201, the electrode 2 having the columnar graphite 203 formed on the surface as shown in FIG.
04 is formed. Then, by arranging the electrode 204 at the center on the ceramic substrate 106a shown in FIG. 1, the electrode 106b can be formed as shown in FIG.

By doing so, it becomes possible to previously form a plurality of electrodes to which columnar graphite as an electron emitting portion is fixed, and for example, to inspect the electron emitting characteristics in advance, and to improve the characteristics. It is also possible to use only. The electrode (conductive plate) 106 on which the columnar graphite 121 is fixedly arranged.
b, so that the mesh portion (electron extraction electrode) 10
A housing 106d with 6e is arranged.

By the way, the columnar graphite 121
Is a carbon nanotube 1 as shown in FIG.
Reference numeral 21a denotes a structure that is assembled in substantially the same direction. FIG. 1C shows the columnar graphite 121.
FIG. 3 is a perspective view showing a cross section cut in the middle of FIG. As shown in FIG. 1D, the carbon nanotube 121a is completely graphitized into a cylindrical shape, has a diameter of about 4 to 50 nm, and has a length on the order of microns. Then, as shown in FIG. 1 (e), the tip is closed by the five-membered ring. This carbon nanotube has two carbon electrodes in helium gas.
By causing a DC arc discharge at a distance of about 2 mm, carbon on the anode side evaporates and can be formed in a deposit aggregated at the tip of the carbon electrode on the cathode side.

That is, the gap between the carbon electrodes is 1 mm.
While maintaining a stable arc discharge in helium, the columnar deposit having substantially the same diameter as the diameter of the anode carbon electrode is formed at the tip of the cathode. The columnar deposit is composed of two regions: a hard shell on the outside and a fragile black core on the inside. And the inner core is
It has a fibrous structure extending along the length of the sediment column. The fibrous structure is the above-described columnar graphite, and columnar graphite can be obtained by cutting out a sediment column or the like. The outer hard shell is a graphite polycrystal.

Then, in the columnar graphite,
A plurality of carbon nanotubes are aggregated together with carbon polyhedral fine particles (nanopolyhedoron). The carbon nanotube is shown in FIG.
In (e), as schematically shown, a single graphite layer is closed in a cylindrical shape, and a plurality of graphite layers are stacked in a nested structure, and each graphite layer is closed in a cylindrical shape. There are shapes that have a structure. And the center part of them is hollow.

As described above, in this embodiment, the columnar graphite 121 composed of the carbon nanotubes 120a is fixedly arranged on the electrode 106b, and the housing 106d is mounted on the ceramic substrate 106a so as to cover them. In this state, the cathode structure 106 was formed. The mesh part 106e
Has a shape protruding spherically in the direction of the phosphor screen 104. The housing 106d has a thickness of about 100
It is formed by press-forming a stainless steel plate material of about μm. The mesh portion 106e is formed to have, for example, a vertical dimension of about 6 mm, a horizontal dimension of about 4 mm, and a height of about 1.25 mm. And the mesh part 106e is 0.5 mm from the tip of the columnar graphite 121.
状態 1 mm apart. In addition, it is better to make these intervals as close as possible without contact.

In the picture tube formed as described above, first, a voltage is supplied to the lead pins 109a and 109b from an external circuit, so that the cathode leads 111a and 111b are supplied.
, An electric field is applied between the electrode 106 and the housing 106d. As a result, a high electric field is concentrated on the end of the carbon nanotube of the columnar graphite 121 fixedly arranged on the electrode 106, and electrons are extracted and emitted from the mesh portion 106e. That is, according to this embodiment, the cathode structure 106 serving as the electron emitting portion is used.
Is the carbon nanotube 1 of columnar graphite 121
A field emission type cold cathode electron source having the emitter 21a is obtained.

Then, a high voltage is supplied to the lead pin 109 from an external circuit, and the anode lead 110 → the anode electrode assembly 10
5 (cylindrical anode 105b) → Electric electrons are accelerated by the cylindrical anode 105b by conducting the respective paths of the contact pieces 107a and applying a high voltage to the Al metal back film 107, Al metal back film 10
7 and penetrates the fluorescent screen 104. As a result,
The fluorescent screen 104 is excited by the electron impact, and emits a luminescent color corresponding to the fluorescent material constituting the fluorescent screen 104 to the face glass 10.
2 to emit light on the front side.

As described above, according to this embodiment, the electron emission portions are formed by arranging carbon nanotubes. As a result, the electron emission portion becomes a field emission type cold cathode electron source. Therefore, according to this embodiment, since the electron-emitting portion does not use a fragile component such as a filament, it can be handled easily and can be easily formed. Also, since there is no need for a heating power supply for the filament, the number of lead pins can be reduced,
Manufacturing can be further simplified.

In the above embodiment, the picture tube has been described, but the present invention is not limited to this. It is needless to say that the present invention can be applied to other fluorescent display devices provided with a light emitting portion made of a phosphor in a vacuum vessel and an electron emission source for emitting the light. For example, an optical filter may be formed between the face glass and the phosphor screen. By forming the optical filter in this manner, a picture tube with a different emission color can be obtained. In addition, a plurality of fluorescent screens may be provided in the same vacuum vessel to form a multicolor image tube. Further, the fluorescent screen may have a desired shape, and may be a flat tube for displaying a character having a desired shape.

[0034]

As described above, according to the present invention, an electron emission component made of a conductive member to which an emitter made of carbon nanotubes made of a cylindrical graphite layer is fixed is formed in advance. The electron-emitting component is arranged at a predetermined position in the envelope, and an electron extracting electrode for extracting electrons from the emitter is arranged on the electron-emitting side of the emitter. In addition, the electron emission component cuts out a predetermined region of a plate of a material constituting the conductive component so that a plurality of shape portions that become conductive members are connected to the frame, and an emitter is provided in a predetermined region of the shape portion. It was formed by cutting off the shape portion where the emitter was formed from the frame.

That is, according to the present invention, first, a field emission type cold cathode electron source can be constituted by the emitter composed of the carbon nanotube and the electron extraction electrode. As a result, according to the present invention, the electron emission portion of the fluorescent display device can be manufactured without using a fragile component such as a filament, and as a result, the fluorescent display device can be manufactured more easily. Further, by preparing the electron-emitting portion as an electron-emitting component in advance, it is possible to inspect the electron-emitting characteristics in advance and use only those having good characteristics.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of an image tube according to an embodiment of the present invention.

FIG. 2 is a columnar graphite 121 as an electron-emitting component.
FIG. 9 is an explanatory diagram for explaining the production of the electrode 106b on which is formed.

FIG. 3 is a configuration diagram showing a configuration of a conventional picture tube.

[Explanation of symbols]

101: glass bulb, 102: face glass, 10
3 ... low melting point frit glass, 104 ... phosphor screen, 105 ...
Anode electrode structure, 105a: ring-shaped anode, 105b: cylindrical anode, 105c: Ba getter, 106: cathode structure, 106a: ceramic substrate, 106b: electrode (conductive plate), 106d: housing, 106e: mesh part (electron drawer) Electrode), 107 ... Al metal back film,
107a: contact piece, 108: stem glass, 108a ...
Exhaust pipe, 109, 109a, 109b ... lead pin, 1
10: anode lead, 111a, 111b: cathode lead, 121: columnar graphite (emitter), 121a
... carbon nanotube, 122 ... conductive adhesive.

Claims (9)

[Claims] 1. An envelope having at least a part of a translucent display surface and having an interior evacuated and a phosphor formed inside the display surface, and emits light by the impact of electrons. In a method of manufacturing a fluorescent display tube having a fluorescent screen, an electron emitting component made of a conductive member to which an emitter made of a carbon nanotube made of a cylindrical graphite layer is fixed is formed in advance, and A fluorescent display device comprising: an emission component disposed at a predetermined position in the envelope; and an electron extraction electrode for extracting electrons from the emitter on the electron emission side of the emitter in the envelope. Manufacturing method. 2. The method of manufacturing a fluorescent display device according to claim 1, wherein the electron-emitting component has a surface on which the emitter is fixed facing the fluorescent screen, and the carbon nanotube has a conductive property. A method for manufacturing a fluorescent display device, wherein the fluorescent display device is fixed with an agent. 3. The method for manufacturing a fluorescent display device according to claim 1, wherein the electron-emitting component becomes the conductive member by cutting out a predetermined region of a plate of a material forming the conductive component. A fluorescent display, wherein a plurality of shaped portions are connected to a frame, the emitter is formed in a predetermined region of the shaped portion, and the shaped portion on which the emitter is formed is separated from the frame to produce a fluorescent display. Device manufacturing method. 4. The method of manufacturing a fluorescent display device according to claim 1, wherein said emitter is made of columnar graphite made of an aggregate of said carbon nanotubes. Device manufacturing method. 5. The method of manufacturing a fluorescent display device according to claim 4, wherein the columnar graphite is disposed with its tip end facing the fluorescent screen. 6. The method for manufacturing a fluorescent display device according to claim 1, wherein the extraction electrode is disposed between the fluorescent screen and the emitter. 7. The method of manufacturing a fluorescent display device according to claim 1, wherein the extraction electrode is disposed between the fluorescent screen and the display surface. . 8. The method for manufacturing a fluorescent display device according to claim 1, wherein an optical filter is disposed between said fluorescent screen and said display surface. 9. The method for manufacturing a fluorescent display device according to claim 1, wherein a metal film is formed on the fluorescent screen after forming the fluorescent screen, and further, between the fluorescent screen and the electron extraction electrode. To
A method for manufacturing a fluorescent display device, wherein an electron accelerating electrode to which a higher potential than the electron extraction electrode is applied is disposed so as to be electrically connected to the metal film.