JPH06139927A - Manufactur of impregantion type cathode structural body - Google Patents

Abstract

PURPOSE:To improve reliability, and set a manufacturing cost low by providing a flare at an edge part of a bottom-equipped cup, inserting a pellet into the bottom-equipped cup, and deforming the flare to the flare. CONSTITUTION:A cup 7 having a bottom is manufactured, and a flare 7b is provided at an edge part of the cup 7, so thickness of the part of the flare 7b in the cup 7 is thicker than thickness of a side part. Next, a sleeve 5 and two lines 4 are press moulded, the two lines 4 are crossed between the cup 7 and the sleeve 5, the lines 4, cup 7, and sleeve 5 are integrally fixed by resistance welding or the like, and a heat treatment is applied in moist hydrogen gas atmosphere. A pellet 8 is then pressurized and inserted into the cup 7, assembly parts such as the sleeve 5 are installed on a lower rod 15, and they are pressurized by an upper rod 14, so the rod 15 escapes in accordance with pressurization till the flare 7b of the cup 7 is pushed by a movable blade 13 to deform toward the pellet 8. Reliability can thus be set high, and manufacturing cost can be made low.

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 an impregnated cathode assembly used in a cathode ray tube such as a color cathode ray tube.

[0002]

2. Description of the Related Art A cathode is an important component that influences the efficiency and life of a cathode ray tube. Among them, the impregnated cathode has a high current density and can be expected to have a long life. It has been attracting attention as a cathode for cathode ray tubes, television image pickup tubes, and the like.

Since this impregnated cathode needs to have a cathode temperature of about 900 to 1000 ° C. at the time of use, it is necessary to improve the thermal efficiency and prevent deformation, peeling and dropping due to a thermal cycle from room temperature to about 1000 ° C. Various ideas have been made.

FIG. 3 is a sectional view showing an impregnated cathode assembly. As shown in the figure, an eyelet 3 made of Fe-Ni-Co is attached to a support 1 made of Fe-Ni via a crystallized glass 2, and two lines made of Re (rhenium) -W are attached to the eyelet 3. 4 is attached, a bottomed sleeve 5 made of Mo is attached to the wire 4, a heater 6 for heating the cathode is provided in the sleeve 5, and a bottomed cup 7 made of Mo is attached to the wire 4. A pellet 8 in which a base body made of a porous body W is impregnated with an electron beam emitting substance made of an alkaline earth metal oxide in a bottomed cup 7.
Is stored.

In a conventional method for manufacturing an impregnated cathode assembly (Japanese Patent Publication No. 61-7697), first, referring to FIG.
As shown in, the Mo plate 7a is placed in the opening of the die 9,
The pellet 8 is placed on the Mo plate 7a, and then the Mo plate 7a and the pellet 8 are sandwiched by the upper rod 10 and the lower rod 11 as shown in FIG. 4 (b). 8 is pushed downward on the paper surface, the pellet 8 is used as a plunger to press-mold the Mo plate 7a to form the bottomed cup 7. Then, as shown in FIG. 4 (c), the upper rod 10 and the lower rod 11 are moved upward. The pellets 8 stored in the bottomed cup 7 are moved up.

Further, in another conventional method for manufacturing an impregnated cathode assembly (Japanese Patent Laid-Open No. 63-76227),
As shown in FIG. 5, a brazing filler metal 12 made of Mo-Ru alloy 12
The bottomed cup 7 and the pellet 8 are brazed together.

[0007]

However, in the method of manufacturing the impregnated cathode structure described with reference to FIG. 4, since the pellet 8 is press-molded as the plunger, the pellet 8 is not formed.
The electron emitting substance is contaminated and the pores on the surface of the W porous body of the pellet 8 are crushed, so that the electron emitting characteristic is significantly deteriorated and the reliability is low.

Further, in the method of manufacturing the impregnated cathode structure described with reference to FIG.
Since a high temperature treatment exceeding 100 ° C. causes coarse crystallization of Mo, the bottomed cup 7 becomes brittle, and the pellet 8 peels off or partially falls off during the use of the cathode ray tube during the production of the impregnated cathode structure. And a heating device for performing high temperature treatment exceeding 2000 ° C. is required, resulting in high manufacturing cost.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method of manufacturing an impregnated-type cathode assembly which has high reliability and is inexpensive to manufacture.

[0010]

In order to achieve this object, in the present invention, a pellet obtained by impregnating a substrate made of a porous high-melting point metal with an electron beam emitting substance made of an alkaline earth metal oxide has a high melting point. In a method of manufacturing an impregnated cathode assembly housed in a bottomed cup made of metal, a flare is provided on an edge of the bottomed cup, the pellet is inserted into the bottomed cup, and then the flare is attached to the pellet side. Transform into.

[0011]

In the method of manufacturing the impregnated cathode structure, the pellet is not press-molded as the plunger, so that the electron emitting material of the pellet is not contaminated.
Moreover, the holes on the surface of the pellet base are not crushed,
Further, since the high temperature treatment is not performed, the refractory metal does not cause coarse crystallization, and a heating device for performing the high temperature treatment is not required.

[0012]

EXAMPLE A method of manufacturing an impregnated cathode assembly according to the present invention will be described with reference to FIG. First, W with an average particle size of 6 μm
The powder is press-molded into a cylindrical shape having an outer diameter of about 1.2 mm and a thickness of about 0.5 mm, and then sintered at a high temperature of 1900 ° C. or higher in a vacuum to produce a substrate made of the porous body W. The porosity of this substrate is 20%. Next, BaO, CaO, and Al ₂ O ₃ which are electron beam emitting substances are added to the substrate in a molar ratio of 4:
A mixture having a composition ratio of 1: 1 is melt-impregnated, and the excess electron beam emitting substance protruding from the substrate is mechanically removed to produce a pellet 8. Next, as shown in FIG. 1A, a plate made of Mo and having a thickness of 50 μm is press-molded to manufacture a bottomed cup 7 having an inner diameter of about 1.2 mm and a height of 0.45 mm. In this case, the flare 7b is provided at the edge of the bottomed cup 7. Then, the flare 7b of the bottomed cup 7
The thickness of the part becomes thicker than the thickness of the side part. Next, a sleeve 5 having a thickness of 0.1 mm and two wires 4 having a diameter of 0.05 mm are press-molded. Next, after crossing the two wires 4 in a cross shape between the bottomed cup 7 and the sleeve 5, the wires 4, the bottomed cup 7, and the sleeve 5 are integrally fixed by resistance welding or the like, and then wet hydrogen is used. Heat treatment is performed in a gas atmosphere. Next, the pellet 8 is pressure-inserted into the bottomed cup 7. Next, as shown in FIG. 1B, an assembly component such as the sleeve 5 is attached to the lower rod 15, and the upper rod 14 applies pressure. Then, as shown in FIG. 1 (c), the lower rod 15 escapes as the upper rod 14 is pressed, and the flare 7b of the bottomed cup 7 is squeezed by the movable blade 13 which is 40%. 7b is deformed toward the pellet 8 side, and the pellet 8 is stored in the bottomed cup 7 with sufficient holding force. Next,
The cathode integrated assembly thus obtained is attached to the eyelet 3 held by the crystallized glass 2 having the support 1 by laser welding or the like, and the heater 6 is provided in the sleeve 5.
Insert.

In this method of manufacturing the impregnated cathode structure, since the pellet 8 is not press-molded as a plunger, the electron emitting material of the pellet 8 is not contaminated and the holes on the surface of the base of the pellet 8 are crushed. It is highly reliable and does not undergo high temperature treatment, so that refractory metal does not undergo coarse crystallization, the bottomed cup 7 does not become brittle, and the impregnated cathode assembly is being manufactured and the cathode ray tube is being used. Moreover, since the pellets 8 do not peel off or partly fall off, the reliability is high, and since a heating device for performing high temperature treatment is not required, the manufacturing cost is low. Moreover, since the pellets 8 are pressure-inserted into the bottomed cup 7 after the bottomed cup 7 is heat-treated in a hydrogen gas atmosphere, the pellets 8 are inserted after the bottomed cup 7 is cleaned. The adhesion between the bottomed cup 7 and the pellet 8 is improved, and the bottomed cup 7 becomes soft and easily deformed.

A method of manufacturing another impregnated cathode assembly according to the present invention will be described with reference to FIG. First, the bottomed cup 7 having the flare 7b is heat-treated in a hydrogen gas atmosphere, and then the pellet 8 is pressure-inserted into the bottomed cup 7.
Next, as shown in FIG. 2 (a), the bottomed cup 7 is set in the opening of the round die 16 of the jig, and pressure is applied by the rod 17. Then, as shown in FIG. 2B, the flare 7b of the bottomed cup 7 is squeezed by the round die 16, the flare 7b is deformed toward the pellet 8 side, and the pellet 8 is held with sufficient holding force. It is stored in. Next, after crossing the two wires 4 in a cross shape between the bottomed cup 7 and the sleeve 5, the wire 4, the bottomed cup 7, and the sleeve 5 are integrally fixed by resistance welding or the like. Next, the cathode integrated assembly thus obtained is attached to the eyelet 3 held by the crystallized glass 2 having the support 1 by laser welding or the like, and the heater 6 is inserted into the sleeve 5.

In the above-described embodiment, the extra electron beam emitting material protruding from the substrate was mechanically removed.
Excessive electron beam emitting substance protruding from the substrate may be removed in pure water.

[0016]

As described above, in the method of manufacturing an impregnated cathode structure according to the present invention, the electron emitting material of the pellet is not contaminated, and the holes on the surface of the pellet substrate are crushed. Since it does not have high reliability and the refractory metal does not cause coarse crystallization, the bottomed cup does not become brittle and the pellet peels off or partially falls off during the production of the impregnated cathode structure or during use of the cathode ray tube. Therefore, the manufacturing cost is low because a heating device for performing high temperature treatment is not required because of high reliability. As described above, the effect of the present invention is remarkable.

[Brief description of drawings]

FIG. 1 is an explanatory view of a method for manufacturing an impregnated cathode assembly according to the present invention.

FIG. 2 is an explanatory view of another method for manufacturing an impregnated cathode assembly according to the present invention.

FIG. 3 is a cross-sectional view showing an impregnated cathode assembly.

FIG. 4 is an explanatory view of a conventional method for manufacturing an impregnated cathode assembly.

FIG. 5 is an explanatory view of a conventional method for manufacturing an impregnated cathode assembly.

[Explanation of symbols]

 7 ... Bottom cup 7b ... Flare 8 ... Pellet

Front page continued (72) Inventor Takashi Kono 3300 Hayano, Mobara-shi, Chiba Hitachi Ltd. Mobara factory

Claims (1)

[Claims] 1. An impregnated cathode assembly in which pellets obtained by impregnating a porous substrate made of a refractory metal with an electron beam emitting substance made of an alkaline earth metal oxide are housed in a bottomed cup made of a refractory metal are manufactured. A method for producing an impregnated cathode assembly, comprising providing a flare at an edge of the bottomed cup, inserting the pellet into the bottomed cup, and deforming the flare toward the pellet.