JP2002075257A - Display tube using filament and welding method of filament - Google Patents

Abstract

PROBLEM TO BE SOLVED: To weld and support the filament on the cathode wiring without using a filament supporting member of a three-dimensional structure. SOLUTION: The filament 14 made of tungsten is welded on a cathode wiring 12 formed on the glass substrate 11 by a metal welding part 13 which is melted and solidified around the filament 14. The filament 14 is held at a prescribed interval by glass fiber 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display tube using a filament, and more particularly to a structure for mounting the filament and a method for welding the filament.

[0002]

2. Description of the Related Art FIG. 7 shows a conventional example in which a filament is fixed to a filament supporting member. A cathode wiring 72 is formed on a glass substrate 71, and a filament support member 73 is attached to the cathode wiring 72.
, A filament 74 is fixed. The filament support member 73 includes a mounting portion 731, a rising portion 732, and a filament support portion 733. The filament 74 is placed on the filament support 733, the metal piece 76 is placed on the filament 74, and the filament support 733 and the metal piece 7 are placed.
6 are pressed by the upper and lower electrodes of the resistance welding machine, a welding current is applied, and the two are spot-welded. The filament 74 is
It is sandwiched and fixed between the filament support portion 733 and the metal piece 76.

[0003]

The filament support member 73 shown in FIG. 7 has a mounting portion 731 for fixing itself to the substrate 71 and a support portion 7 for supporting the filament 74.
33 and a rising portion 732 for holding the filament 74 at a predetermined height, and has a three-dimensional structure and a complicated shape. Therefore, the operation of fixing the filament support member 73 to the cathode wiring 72 and the operation of fixing the filament to the support portion 733 are troublesome, and the processing cost of the filament support member 73 is increased, which is a bottleneck in reducing the display tube manufacturing cost. I was In addition, since the filament support member 73 has a three-dimensional structure, it has been an obstacle to thinning the display tube. In view of these points, an object of the present invention is to weld a filament to a cathode wiring without using a conventional expensive and complicated-shaped filament support member.

[0004]

In the display tube of the present invention, the filament is welded to the cathode wiring formed on the substrate by a metal which is melted and solidified around the filament. In the display tube of the present invention, the filament is welded to a metal plate fixed to the cathode wiring formed on the substrate by a metal that has been melted and solidified around the filament. The display tube of the present invention holds a filament between a metal plate fixed to a cathode wiring formed on a substrate and a metal piece for welding,
The metal plate and the welding metal piece are welded. In the display tube of the present invention, in the display tube, one or both of the cathode wiring and the metal plate fixed to the cathode wiring are filled with crystallized glass, and the metal plate is fixed to the cathode wiring. It is. In the display tube of the present invention, in the display tube, the metal melted and solidified around the filament is a metal having a lower melting point than the filament.

According to the present invention, a filament and a metal piece for forming a welding layer are held in this order on a cathode wiring or a metal plate fixed to the cathode wiring, and the metal piece and the filament for forming a welding layer are heated by laser light. Then, a metal piece for forming a welding layer is melted, a welding layer is formed around the filament, and the filament is welded to a cathode wiring or a metal plate fixed to the cathode wiring. The present invention holds a metal piece and a filament for forming a welding layer in this order on a cathode wiring or a metal plate fixed to the cathode wiring, and heats the filament and the metal piece for forming a welding layer by laser light to form a welding layer. The forming metal piece is melted, a welding layer is formed around the filament, and the filament is welded to the cathode wiring or a metal plate fixed to the cathode wiring. The present invention provides a method for holding a metal piece for forming a welding layer, a filament and a metal piece for forming a welding layer on a cathode wiring or a metal plate fixed to the cathode wiring in this order, and forming a metal piece and a filament for forming both welding layers. Is heated by a laser beam to melt the metal pieces for forming both welding layers, a welding layer is formed around the filament, and the filament is welded to the cathode wiring or a metal plate fixed to the cathode wiring.

[0006]

FIG. 1 is a plan view and a sectional view of a portion for welding and supporting a filament of a display tube according to a first embodiment of the present invention. FIG. 1 (a) is a plan view, FIG.
FIG. 1B is a cross-sectional view taken along the line XX of FIG.
FIG. 1C is an enlarged cross-sectional view taken along the line YY in FIG. 11 is a glass substrate, 12 is a glass substrate 11
The aluminum cathode wiring 13 formed on the welding wire 13 welds the filament to the cathode wiring 12.
Is a filament, and 15 is a glass fiber (or a ceramic round bar or the like) for a spacer for holding the filament 14 at a predetermined height. The filament 14
It is made of tungsten or an alloy of tungsten (eg, rhenium tungsten) having a diameter of about 20 μm. A necessary portion of the filament 14 (for example, a portion corresponding to the display area) is coated with a carbonate as an electron emitting material by electrodeposition on the outer periphery of a core wire of tungsten or a tungsten alloy. In the welding portion 13, aluminum, nickel, and the like are melted and solidified around the filament 14, and the filament 14 is welded to the cathode wiring 12.

2A and 2B are a plan view and a sectional view of a portion for welding and supporting a filament of a display tube according to a second embodiment of the present invention. FIG. 2A is a plan view and FIG. 2) is a sectional view taken along the line ZZ in FIG. 2 (a), and FIG.
(A) is an enlarged sectional view of a WW portion. 21 is a glass substrate, 22 is an aluminum cathode wiring formed on the glass substrate 21, 23 is a welded portion for welding a filament to the cathode wiring 22, 24 is a filament,
25 is a glass fiber for a spacer that holds the filament 24 at a predetermined height, and 26 is a 426 alloy (N
i 42%, Cr 6%, and the remaining Fe). The filament 24 is made of tungsten or an alloy of tungsten having a diameter of about 20 μm. The metal plate 26 is 426
A metal other than an alloy may be used, but when the metal plate 26 is fixed to the cathode wiring 22 by crystallized glass, a metal (for example, tin) having a thermal expansion coefficient similar to that of crystallized glass is preferable.

In this embodiment, a metal plate 26 is fixed to the cathode wiring 22, and a filament 24 is welded to the metal plate 26. As in the case of the welded portion 13 of FIG. 1, the welded portion 23 is formed by melting aluminum, nickel, etc.
6 is welded. In the present embodiment, the filament 24 is not directly welded to the cathode wiring 22 but is welded to the metal plate 26. Therefore, even when the thickness of the cathode wiring 22 is thin, the cathode wiring 22 evaporates during welding to cause disconnection. It will not be damaged.

FIG. 3 is a cross-sectional view for explaining a method of welding the filament to the cathode wiring or the metal plate fixed to the cathode wiring in FIGS. 1C and 2C. Y-Y of (a) and WW of FIG. 2 (a)
It corresponds to. Here, a method of directly welding the filament to the cathode wiring will be described. However, the case of welding to a metal plate fixed to the cathode wiring is also the same as the welding method of FIG. 31 is a glass substrate, 32 is an aluminum cathode wiring having a thickness of about 1.2 μm, 34
Is a tungsten or tungsten alloy filament having a diameter of about 20 μm, and 33, 331, and 332 have a thickness of about 2 μm.
It is a metal piece for forming a welding layer such as aluminum or nickel having a thickness of 0 μm.

3A, a metal piece 33 is temporarily fixed to a cathode wiring 32 formed on a glass substrate 31 with an acrylic solution or the like, and a filament 34 is placed on the metal piece 33.
And the filament 34 and the metal piece 33 are irradiated with a YAG laser beam. Irradiation spot diameter is about 0.4m
At m, the metal piece 33 is overheated to the extent that it is melted. This heating causes the metal piece 33 to melt, but the filament 34
Does not melt because the melting point is higher than the metal piece 33. The molten metal piece 33 forms a welding layer serving as a welding portion in FIG. 1C and FIG. 2C around the filament 34, and the welding layer solidifies to form the welding portion, and the filament 34 becomes a cathode. Weld to wiring 32.

In the method shown in FIG. 3B, a filament 34 is held on the cathode wiring 32, a metal piece 33 is temporarily fixed thereon with an acrylic solution or the like, and a YAG laser beam is applied to the metal piece 33 and the filament 34. Irradiation is performed to weld the filament 34 to the cathode wiring 32 as in FIG.

In the method shown in FIG. 3C, a metal piece 331 is temporarily fixed on the cathode wiring 32 with an acrylic solution or the like, a filament 34 is temporarily fixed on the metal piece 331 with a YAG laser beam, and a metal piece is placed thereon. 332 is temporarily fixed with an acrylic solution or the like, and YAG is attached to the metal pieces 331 and 332 and the filament 34.
By irradiating a laser beam, the filament 34 is welded to the cathode wiring 32 as in FIG.

3 (a), 3 (b) and 3 (c), the method of temporarily fixing the metal pieces 33, 331 and 332 with an acrylic solution has been described, but this temporary fixing may be omitted. The material of the metal pieces 33, 331, and 332 for forming the welding layer is as follows.
Although aluminum and nickel have been described, in addition to them, stainless steel, alloys such as stainless steel, gold, titanium,
Any metal having a lower melting point than tungsten, such as tantalum, niobium, molybdenum, zirconium, copper, silver, etc., may be used.

Since the filament only needs to expose tungsten at a portion to be welded, for example, in the case of a filament in which a tungsten wire is coated with a carbonate, the carbonate at the welded portion is removed by a laser beam. Alternatively, it may be removed by a mechanical or chemical method and welded. If the filament is welded to the filament support member with laser light without removing the carbonate in the welded part, the carbonate absorbs the laser light because the carbonate absorbs higher than the tungsten wire. Absorption causes a high temperature and the tungsten wire may be broken. Therefore, it is better to remove the carbonate in the welded portion. The laser used for welding may be a solid laser other than the YAG laser, a gas laser, an excimer laser, or the like, in addition to the YAG laser. Since laser light is used for welding this filament, it is possible to easily weld the filament without damaging the cathode wiring by changing the output of the laser light and the diameter of the irradiation spot. It is possible to cope with various kinds of cathode wiring.

FIG. 4 is a diagram showing the structure of FIG.
FIG. 2A is a cross-sectional view for explaining a method of fixing the metal plate 26 of the 426 alloy to FIG. 2A, and the direction of the cross section corresponds to WW in FIG. In FIG. 4A, the end or the periphery of the metal plate 26 is fixed to the cathode wiring 22 formed on the substrate 21 by the crystallized glass 27. In FIG. 4B, a hole is formed in the cathode wiring 22, and a metal plate 26 is fixed to the cathode wiring 22 by crystallized glass 27 filling the hole.
In this case, since one end of the crystallized glass 27 is adhered to the substrate 21, the fixing strength of the metal plate 26 is higher than in the case of FIG.

In FIG. 4C, holes are provided in both the cathode wiring 22 and the metal plate 26, and the metal plate 26 is fixed by crystallized glass 27 filling the holes. The hole for filling the crystallized glass 27 may be formed at the center of the metal plate 26. In this case, one end of the crystallized glass 27 is adhered to the substrate 21 through the cathode wiring 22 and the hole of the metal plate 26, and the central portion of the metal plate 26 is also fixed by the crystallized glass. The fixing strength is shown in FIG.
Higher than in the case of. The surface of the cathode wiring is oxidized and becomes high resistance in a firing step at the time of producing the anode substrate, for example, a firing step such as cloth firing, graphite electrode firing, seal firing, and phosphor firing. When the two are fixed to each other and are welded by laser light, the oxide film of the cathode wiring is removed, and the electrical conduction between the two can be further ensured.

FIG. 5 is a view showing a sectional structure of the display tube according to the embodiment of the present invention.
-X and ZZ in FIG. 2A. 511
Is a glass anode side substrate, 512 is a glass front side substrate, 513 is a glass side plate, 54 is a filament, 55 is a glass fiber for a spacer, 57 is a portion for welding and supporting the filament, 58
1 is an anode electrode and 582 is a phosphor. Part 5
Reference numeral 7 has the same structure as that of the portion for welding and supporting the filament of FIGS.

FIG. 5A shows an example in which the portion 57 is formed on the anode-side substrate 511. The distance H1 between the anode side substrate 511 and the front side substrate 512 is 1.5 mm, and the distance H2 between the filament 54 and the anode side substrate 511 is H2.
Is 1.0 mm. The diameter of the glass fiber 55 is selected such that the distance H2 between the filament 54 and the anode-side substrate 511 is 1.0 mm. FIG. 5 (b)
Is an example in which the portion 57 is formed on the front substrate 512. The distance H1 between the anode-side substrate 511 and the front-side substrate 512 is 1.5 mm, and the distance H3 between the filament 54 and the anode-side substrate 511 is 1.0 mm. The diameter of the glass fiber 55 is selected such that the distance H3 between the filament 54 and the anode-side substrate 511 is 1.0 mm. If a part or the whole of the filament 54 is in a coil shape, the filament can be stretched without slack.

In the present embodiment, the filament and the anode electrode can be held at a predetermined distance by the glass fiber without using a conventional filament support member having a complicated structure, and the distance is a predetermined diameter. It can be arbitrarily changed only by selecting the glass fiber.

FIG. 6 is a perspective view of a portion for welding and supporting a filament according to a third embodiment of the present invention.
61 is a glass substrate, 62 is a cathode wiring, 63
Is a metal plate such as 426 alloy, 64 is a filament, 6
5 is a glass fiber for a spacer, and 66 is a welding metal piece such as stainless steel. The welding metal piece 66 is
It is welded to the metal plate 63. The filament 64 is sandwiched and fixed between the welding metal piece 66 and the metal plate 63. The portion for welding and supporting the filament may be formed on either the anode-side substrate or the front-side substrate as in FIG.

The metal plate 63 is mounted on the substrate 6 by the method shown in FIG.
Stick to 1. When the filament 64 has a part or whole of a coil shape, the filament can be stretched without slack. In the present embodiment, the filament is sandwiched and fixed between the metal piece 66 for welding and the metal plate 63, so that an expensive filament support member having a three-dimensional structure as in the related art is not required.

[0022]

According to the present invention, since the filament is welded to the cathode wiring or the metal plate fixed to the cathode wiring by the metal which is melted and solidified around the filament, the conventional complicated shape and expensive three-dimensional structure are required. No filament support member is required. Therefore, according to the present invention, the display tube can be manufactured at low cost. In the case where the filament is directly welded to the cathode wiring, there is no need to fix the member to which the filament is welded, and when using a metal plate, the metal plate has no three-dimensional structure. Can be. Further, when the filament is welded to the cathode wiring or the metal plate, it is sufficient to weld the filament to a flat portion, so that the positioning and welding work are simplified.

In the present invention, the filament is welded to the cathode wiring or the metal plate by the metal that has been melted and solidified around the filament, so that the filament is welded strongly. Since the present invention does not use a filament support member having a three-dimensional structure, the display tube can be made thinner. According to the present invention, the filament is welded to the metal plate fixed to the cathode wiring. Therefore, even when the thickness of the cathode wiring is thin during the welding of the filament, the cathode wiring is not damaged such as disconnection.

According to the present invention, the filament is welded directly to the cathode wiring or to a metal plate fixed to the cathode wiring. Therefore, the portion for welding and supporting the filament also has a function as a power supply portion to the filament. .

[Brief description of the drawings]

FIG. 1 is a perspective view and a sectional view of a portion for welding and supporting a filament of a display tube according to a first embodiment of the present invention.

FIGS. 2A and 2B are a perspective view and a sectional view of a portion for welding and supporting a filament of a display tube according to a second embodiment of the present invention.

FIG. 3 is an explanatory diagram of a method for welding a filament to a cathode wiring according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram of a method for fixing a metal plate to which filaments are welded according to the embodiment of the present invention.

FIG. 5 is a sectional view of a display tube according to the embodiment of the present invention.

FIG. 6 is a perspective view of a portion for welding and supporting a filament of a display tube according to a third embodiment of the present invention.

FIG. 7 is a perspective view of a portion for fixing and supporting a filament of a conventional display tube.

[Explanation of symbols]

 11, 21, 31, 61 Glass substrate 12, 22, 32, 62 Cathode wiring 13, 23 Welded part 14, 24, 34, 54, 64 Filament 15, 25, 55, 65 Glass fiber 26, 63 Fixed to cathode wiring Metal plate 27 Crystallized glass 33, 331, 332 Metal piece for forming weld layer 511 Anode substrate of glass 512 Front substrate of glass 513 Side plate of glass 66 Metal piece for welding

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuyoshi Ishikawa 629 Futaba Electronics Industry Co., Ltd., Oshiba, Mobara City, Chiba Prefecture Inventor Satoshi Yoshimura 629 Oshiba, Mobara-shi, Chiba Futaba Electronics Co., Ltd. In-house F-term (reference) 5C027 CC10 5C036 EE14 EE15 EG13 EH26

Claims (8)

[Claims] 1. A display tube wherein a filament is welded to a cathode wiring formed on a substrate by a metal melted and solidified around the filament. 2. A display tube wherein a filament is welded to a metal plate fixed to a cathode wiring formed on a substrate by a metal melted and solidified around the filament. 3. A filament is sandwiched between a metal plate fixed to a cathode wiring formed on a substrate and a metal piece for welding,
A display tube wherein the metal plate and a metal piece for welding are welded. 4. The display tube according to claim 2, wherein crystallized glass is filled into holes formed in one or both of the cathode wiring and the metal plate fixed to the cathode wiring, and the cathode wiring is provided. A display tube, wherein the metal plate is fixed to the display tube. 5. The display tube according to claim 1, wherein the metal melted and solidified around the filament is:
A display tube characterized by being a metal having a lower melting point than a filament. 6. A filament and a metal piece for forming a welding layer are held in this order on a cathode wiring or a metal plate fixed to the cathode wiring, and the metal piece and the filament for forming a welding layer are heated by laser light and welded. A method for welding a filament of a display tube, comprising melting a metal piece for forming a layer, forming a welding layer around the filament, and welding the filament to a cathode wiring or a metal plate fixed to the cathode wiring. 7. A metal wire for fixing a welding layer and a filament are held in this order on a cathode wiring or a metal plate fixed to the cathode wiring, and the filament and the metal piece for forming a welding layer are welded by heating with a laser beam. A method for welding a filament of a display tube, comprising melting a metal piece for forming a layer, forming a welding layer around the filament, and welding the filament to a cathode wiring or a metal plate fixed to the cathode wiring. 8. A metal layer for forming a welding layer, a filament and a metal piece for forming a welding layer are held in this order on a cathode wiring or a metal plate fixed to the cathode wiring, and the metal pieces for forming both welding layers are formed. The method is characterized in that the filament is heated by a laser beam to melt the metal pieces for forming both welding layers, a welding layer is formed around the filament, and the filament is welded to a cathode wiring or a metal plate fixed to the cathode wiring. Display tube filament welding method.