JPH0963458A - Impregnated cathode body structure, and manufacture of it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an impregnated cathode body structure, capable of preventing the deformation of a suspending metallic fine wire, and also welding in high reliability, at the time of the welding of a bottomed metallic cup, a suspending metallic fine wire, and a bottomed cylindrical metallic sleeve. SOLUTION: This body structure is provided with a bottomed metallic cup 1 for storing a cathode substrate 2, wherein electron radiating material is impregnated into high-melting point porous metal, in the inside; a bottomed cylindrical metallic sleeve 3 housing a heater 4; and plural suspending metallic fine wires 6 bridged at both sides of a cylindrical retaining member 5. The wire 6 is interposed, between both bottom surfaces of a bottomed metallic cup 1 and a bottomed cylindrical metallic metallic sleeve 3, to weld these two bottom surfaces and the fine wire 6 to integrally join the cup 1 and the metallic sleeve 3 together with the fine wire 6. At that time, the cup 1, the wire 6, and the sleeve 3 are integrally joined by electron beam welding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impregnated cathode assembly and a method of manufacturing the same, and more particularly, to a welded portion of a bottomed metal cup, a suspension metal wire, and a bottomed cylindrical metal sleeve forming the impregnated cathode assembly. The present invention relates to an impregnated cathode assembly in which electron beam welding is performed so that the welding strength is constant and a method for manufacturing the same.

[0002]

2. Description of the Related Art Generally, a cathode ray tube is composed of many components, but a cathode is a component that greatly influences efficiency and life. When an impregnated cathode structure is used for the cathode of the cathode ray tube, relatively high current density characteristics and long life characteristics can be expected.

By the way, the impregnated cathode assembly is usually
Porous refractory metal, eg powdered tungsten (W)
A refractory metal containing a pellet-shaped cathode substrate impregnated with a mixture of an electron emitting substance, for example, barium oxide (BaO), calcium oxide (CaO), and alumina (Al ₂ O ₃ ), which has been press-molded. , A bottomed metal cup made of molybdenum (Mo), a refractory metal containing a heater, for example, a bottomed cylindrical metal sleeve made of molybdenum (Mo), and a metal eyelet (cylindrical holding member)
And a bottom surface of the bottomed metal cup and a bottom surface of the bottomed cylindrical metal sleeve between the refractory metal and the plurality of suspension metal wires made of, for example, tungsten (W). After facing each other with a plurality of thin metal wires for suspension interposed, the bottom of the bottomed metal cup and the bottom of the bottomed cylindrical metal sleeve are welded together to form a bottomed metal cup and a bottomed cylindrical metal sleeve. Is integrally connected with a plurality of thin metal wires for suspension.

In this case, in welding the bottom surface of the bottomed metal cup and the bottom surface of the bottomed cylindrical metal sleeve in the known impregnated cathode assembly, the inner bottom surface of the bottomed metal cup and the inner surface of the bottomed cylindrical metal sleeve are welded. Electrodes are arranged between the electrodes and the bottom surface, respectively, and a high voltage is applied between these two electrodes.
Resistance welding is used to weld the bottom surface of the bottomed metal cup and the bottom surface of the cylindrical metal sleeve with multiple thin metal wires for suspension by passing a high current between two electrodes to melt the weld. Has been.

[0005]

In the known impregnated cathode assembly, when resistance welding is used for welding the bottomed metal cup, the plurality of suspension metal wires and the bottomed cylindrical metal sleeve, the bottomed metal cup is used. Since all of the metal cup, thin metal wire for suspension, and bottomed cylindrical metal sleeve are made of high-melting point metal, it is necessary to heat the welded part at the time of welding. The deformation of the parts becomes large, and especially in the welded portion, the thin metal wire made of tungsten (W) is the bottom surface of the bottomed metal cup made of molybdenum (Mo) and / or the bottomed cylindrical metal sleeve made of molybdenum (Mo). It will be in the state of digging into the bottom of the. Further, if the temperature of the welded portion is lowered in order to avoid such deformation of the components, the metal melting in the welded portion becomes insufficient.

As described above, in the known impregnated cathode assembly, the metal thin wire for suspension is greatly deformed when the bottomed metal cup, the metal thin wire for suspension, and the cylindrical metal sleeve with bottom are resistance-welded. There is a problem that the life of the tube, that is, the life of the impregnated cathode structure is shortened, and that various kinds of heat treatment in the cathode ray tube manufacturing process after that, it is necessary to carefully perform work so that the deformation of the thin metal wire for suspension does not proceed. Further, if it is attempted to avoid deformation of the suspension thin metal wire, there is also a problem that reliable metal welding cannot be performed because the metal fusion in the welded portion becomes insufficient.

The present invention solves the above problems, and an object thereof is to prevent deformation of the suspension thin metal wire during welding of the bottomed metal cup, the suspension thin metal wire, and the bottomed cylindrical metal sleeve. An object of the present invention is to provide an impregnated cathode assembly which can be welded with high reliability and a method for manufacturing the same.

[0008]

In order to achieve the above-mentioned object, the present invention provides a bottomed metal cup having therein a cathode substrate in which a refractory porous metal is impregnated with an electron emitting substance,
A bottomed cylindrical metal sleeve containing a heater; and a plurality of suspension metal wires bridging the end face of the cylindrical holding member, the bottom surface of the bottomed metal cup and the bottomed cylindrical metal sleeve. The plurality of suspension thin metal wires are interposed between the bottom surface and the bottom, and the two bottom surfaces and the plurality of suspension thin metal wires are welded together to form the bottomed metal cup and the bottomed cylindrical metal sleeve. In an impregnated cathode structure integrally joined with a plurality of suspension metal wires, the bottomed metal cup, the plurality of suspension metal wires and the bottomed cylindrical metal sleeve are integrally connected by electron beam welding. A certain first means is provided.

Further, in order to achieve the above object, the present invention has a bottomed metal cup in which a cathode substrate in which a high melting point porous metal is impregnated with an electron emitting substance is housed, and a heater which is not yet included. A step of preparing a bottom cylindrical metal sleeve and a plurality of thin metal wires for suspension bridged to the end surface of the cylindrical holding member; a bottom surface of the bottomed metal cup and a bottom surface of the bottomed cylindrical metal sleeve; The bottomed metal cup, the plurality of suspension metal wires, and the bottomed cylindrical metal sleeve are overlapped with each other while facing each other and interposing the plurality of suspension metal thin wires in a state of being positioned between the two bottom surfaces. The step of aligning, irradiating with an electron beam from the opening side of the bottomed cylindrical metal sleeve toward the bottom side thereof, the bottomed metal cup, the plurality of suspension metal wires and the bottomed cylindrical metal sleeve. And over Bed comprising a second means of producing impregnated cathode structure through the step of integrally bonded by electron beam welding.

[0010]

According to the first means, when the bottom surface of the bottomed metal cup, the plurality of thin metal wires for suspension, and the bottom surface of the bottomed cylindrical metal sleeve are welded, welding by electron beam welding is performed. At the time of such electron beam welding, by adjusting the beam diameter and beam intensity of the electron beam, the range to be welded is specified, and the degree of metal melting in the weld is adjusted as appropriate. It is possible to obtain an impregnated-type cathode assembly which has high reliability with respect to, and does not involve deformation of the metal wire for suspension during welding.

According to the second means, the bottom of the bottomed metal cup, the plurality of suspension metal wires, and the bottom of the bottomed cylindrical metal sleeve are placed on top of each other. We irradiate the electron beam from the opening side of the shaped metal sleeve toward the bottom side and weld the bottomed metal cup, the multiple thin metal wires for suspension, and the bottomed cylindrical metal sleeve. Since the beam diameter and beam intensity of the electron beam to be welded can be easily adjusted, if the range to be welded is specified or the metal melting temperature in the weld is finely adjusted, it has high reliability for welding. However, an impregnated cathode assembly can be manufactured without deformation of the suspension thin metal wire during welding.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view showing the construction of an embodiment of an impregnated cathode assembly according to the present invention.

In FIG. 1, 1 is a bottomed metal cup made of molybdenum (Mo), 2 is a powdered tungsten (W) which is press-molded to form a porous metal pellet, and barium oxide (BaO) is formed on the porous metal pellet. ), Calcium oxide (CaO), and alumina (Al ₂ O ₃ ) are mixed and impregnated with a cathode substrate, 3 is a bottomed cylindrical metal sleeve made of molybdenum (Mo), and 4 is an indirect heat Type heater, 5 a cylindrical metal eyelet, 6 a fine metal wire for suspension made of tungsten (W), 7 a crystallized glass holding part,
Reference numeral 8 is a cylinder member, and 9 is a pin member.

In the bottomed metal cup 1, the cathode base 2 is housed inside the cup, and in the bottomed cylindrical metal sleeve 3, the indirectly heated heater 4 is included inside the sleeve. The metal eyelet 5 has a circular one end face side, and a plurality of suspension metal thin wires 6 are bridge-connected in the radial direction in the radial direction. The bottomed metal cup 1 and the cylindrical metal sleeve 3 are arranged so as to face each other by sandwiching a plurality of thin metal wires 6 for suspension, and the bottom surfaces are joined to each other, and a part of the joining surface is welded by electron beam welding. The crystallized glass holding unit 7 holds the metal eyelet 5 by fitting the metal eyelet 5 in the central portion. One end of the cylinder member 8 is melt-bonded to the crystallized glass holding part 7, and the pin member 9 is also melt-bonded to the crystallized glass holding part 7 at one end. The holding part 7 is held together with the metal eyelet 5. In this case, the bottomed metal cup 1 and the cylindrical metal sleeve 3 are integrally formed with a plurality of suspension metal thin wires 6, and the cathode base 2 is stored in the bottomed metal cup 1.
In addition, the indirectly heated heater 4 is enclosed in the cylindrical metal sleeve 3 and is suspended in the metal eyelet 5.

The impregnated cathode assembly according to the above construction is
The cathode ray tube is assembled together with other components into the cathode ray tube, and predetermined processing is performed on the cathode ray tube to complete the cathode ray tube.

In this completed cathode ray tube, when electric power is supplied to the rod-heat type heater 4 of the impregnated cathode structure and predetermined operating voltages are supplied to various electrodes in the cathode ray tube (not shown), the rod-heat type heater. An electron beam is radiated from the cathode substrate 2 heated by 4, and the radiated electron beam projects a fluorescent film provided on the inner surface of the panel portion to display a desired image on the fluorescent film. .
And such an image display operation in the cathode ray tube is
Since this is well known in the art, a detailed description of the operation will be omitted.

In the impregnated cathode assembly of this embodiment, when the bottom surface of the bottomed metal cup 1 and the bottom surface of the cylindrical metal sleeve 3 are integrally formed with a plurality of thin metal wires 6 for suspension,
It is characterized in that electron beam welding is used instead of resistance welding as in the known impregnated cathode structure. If electron beam welding is used, it is possible to easily adjust the intensity of the electron beam applied to the weld and to narrow it down.Therefore, fine control of the metal melting temperature in the weld is used to suspend the metal during welding. It is possible to minimize the deformation of the thin metal wire 6 for use, and it is also possible to appropriately adjust the size of the welded portion, which has high reliability with respect to the welded portion, and is a metal for suspension during welding. An impregnated cathode structure can be formed without deformation of the thin wire 6.

Next, FIG. 2 is a cross-sectional view showing the situation when electron beam welding is performed in the case of manufacturing the impregnated cathode assembly according to the present invention shown in FIG.

In FIG. 2, 10 is a welded portion, 11 is an electron beam, and other components that are the same as those shown in FIG. 1 are given the same reference numerals.

An example of the method of manufacturing the impregnated cathode structure according to the present invention will be described with reference to FIG.

First, powdered tungsten (W) having an average particle diameter of about 6 μm is press-molded to form a cylindrical body having an outer diameter of about 1.0 mm and a thickness of about 0.55 mm. Sintering in vacuum at temperatures above 1900 ° C. produces porous metal pellets with a porosity of about 20%. Next, a porous metal pellet was melt-impregnated with an electron-emitting substance prepared by mixing barium oxide (BaO), calcium oxide (CaO), and alumina (Al ₂ O ₃ ) at a molar ratio of 4: 1: 1 to form a porous metal pellet. Excessive electron emitting material protruding from the metal pellet is washed with pure water to form the cathode substrate 2.

Next, molybdenum (M
The plate of o) is press-molded to manufacture the bottomed metal cup 1 having an inner diameter of about 1.0 mm and a height of about 0.5 mm. Subsequently, the cathode substrate 2 is housed and fixed inside the bottomed metal cup 1. Further, a molybdenum (Mo) plate having a plate thickness of 0.1 mm is press-molded to manufacture the bottomed cylindrical metal sleeve 3, and the bottomed cylindrical metal sleeve 3 is blackened. Further, a cylindrical metal eyelet 5 is formed, and the wire diameter is 30 μm on one end surface of the metal eyelet 5.
A plurality of thin metal wires 6 made of tungsten (W) for suspension are welded in the radial direction.

Next, an electron beam welding machine is prepared, and then, as shown in FIG. 2, the bottom surface of the bottomed metal cup 1 accommodating the cathode substrate 2 and the bottomed cylindrical shape subjected to the blackening treatment. Positioning of a plurality of suspended metal thin wires 6 in an intersecting state with the bottom surface of the metal sleeve 3 is performed. Then, using an electron beam welding machine, the electron beam 11 is irradiated from the opening side of the bottomed cylindrical metal sleeve 3 toward the welded portion 10 on the bottom surface of the sleeve, and the bottom surface of the bottomed metal cup 1 and the bottomed cylindrical metal. The bottom surface of the sleeve 3 is welded together with a plurality of thin metal wires 6 for suspension, and the bottomed metal cup 1 and the bottomed cylindrical metal sleeve 3 integrated in the metal eyelet 5 are suspended.

Next, the metal eyelet 5 suspending the bottomed metal cup 1 and the bottomed cylindrical metal sleeve 3 integrated with each other is attached to the center of the crystallized glass holding portion 7 to which the cylinder member 8 and the pin member 9 are attached. Then, the indirectly heated heater 4 is enclosed in the bottomed cylindrical metal sleeve 3 to complete the impregnated cathode assembly.

In the method of manufacturing the impregnated cathode assembly according to this embodiment, the bottomed metal cup 1 and the bottomed cylindrical metal sleeve 3 are used.
This is characterized in that electron beam welding is carried out when and are welded together with a plurality of thin metal wires 6 for suspension. When performing electron beam welding, the electron beam 11 with which the welding portion is irradiated can be easily adjusted in intensity and narrowed down. Therefore, by finely controlling the metal melting temperature in the welding portion 10, Not only can the deformation of the suspension thin metal wire 6 during welding be suppressed to a minimum, but the size of the welded portion 10 can also be adjusted as appropriate, providing high reliability for the welded portion 10. However, the impregnated cathode assembly can be manufactured without deformation of the suspension thin metal wires 6 during welding.

[0027]

As described in detail above, according to the invention of claim 1, the bottom surface of the bottomed metal cup, the plurality of suspension metal wires, and the bottom surface of the bottomed cylindrical metal sleeve are provided. Welding by electron beam welding is used for welding, and during such electron beam welding, by adjusting the beam diameter and beam intensity of the electron beam, the range to be welded can be specified and the metal melting of the welded part can be prevented. Since the degree is adjusted appropriately, there is an effect that it has high reliability for welding and that an impregnated type cathode structure without deformation of the metal wire for suspension can be obtained at the time of welding, and electron beam welding can be performed at low cost. Therefore, there is also an effect that an inexpensive impregnated cathode structure can be obtained.

According to the second aspect of the present invention, after the bottom surface of the bottomed metal cup, the plurality of thin metal wires for suspension, and the bottom surface of the bottomed cylindrical metal sleeve are stacked, respectively, We irradiate an electron beam from the opening side of the bottom cylindrical metal sleeve toward the bottom side and weld the bottomed metal cup, the multiple thin metal wires for suspension, and the bottomed cylindrical metal sleeve. Since the beam diameter and beam intensity of the electron beam to be irradiated can be easily adjusted, if the range to be welded is specified or the metal melting temperature at the weld is finely adjusted, high reliability for welding is obtained. And has an effect that an impregnated cathode assembly can be manufactured without deformation of the suspension thin metal wire during welding,
Since the electron beam welding can be performed at low cost, there is also an effect that the impregnated cathode structure can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the configuration of an embodiment of an impregnated cathode assembly according to the present invention.

FIG. 2 is a cross-sectional configuration diagram showing a situation when electron beam welding is performed in the case of manufacturing the impregnated cathode structure according to the present invention shown in FIG.

[Explanation of symbols]

 1 Bottomed Metal Cup 2 Cathode Base 3 Bottomed Cylindrical Metal Sleeve 4 Indirect Heat Type Heater 5 Cylindrical Metal Eyelet 6 Metallic Wire for Suspension 7 Crystallized Glass Holding Section 8 Cylinder Member 9 Pin Member 10 Welding Section 11 Electron Beam

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Kono 3350 Hayano, Mobara-shi, Chiba Hitachi Electric Devices Co., Ltd.

Claims (2)

[Claims] 1. A bottomed metal cup having therein a cathode substrate in which a high melting point porous metal is impregnated with an electron emitting substance,
A bottomed cylindrical metal sleeve containing a heater; and a plurality of suspension metal wires bridging the end face of the cylindrical holding member, the bottom surface of the bottomed metal cup and the bottomed cylindrical metal sleeve. The plurality of suspension thin metal wires are interposed between the bottom surface and the bottom, and the two bottom surfaces and the plurality of suspension thin metal wires are welded together to form the bottomed metal cup and the bottomed cylindrical metal sleeve. In an impregnated cathode structure integrally joined with a plurality of suspension metal wires, the bottomed metal cup, the plurality of suspension metal wires and the bottomed cylindrical metal sleeve are integrally connected by electron beam welding. An impregnated cathode assembly characterized by the following. 2. A bottomed metal cup having therein a cathode substrate in which a high melting point porous metal is impregnated with an electron emitting substance,
A step of preparing a bottomed cylindrical metal sleeve that does not yet include a heater and a plurality of suspension metal wires bridging the end surface of the cylindrical holding member, the bottom surface of the bottomed metal cup and the bottomed metal cup The bottom surface of the cylindrical metal sleeve is made to face each other, and the plurality of suspension metal thin wires are interposed between the two bottom surfaces in a positioned state, and the bottomed metal cup, the plurality of suspension metal thin wires, and The step of stacking the bottomed cylindrical metal sleeves, irradiating with an electron beam from the opening side of the bottomed cylindrical metal sleeve toward the bottom side thereof, and the bottomed metal cup and the plurality of suspension metal wires. A method for manufacturing an impregnated cathode assembly, comprising manufacturing the impregnated cathode assembly through a step of integrally joining the bottomed cylindrical metal sleeve by electron beam welding.