JPH09298027A - Impregnated type cathode structure, its manufacture, electron gun structure, and electron tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the yield without fusing a cathode fixing member in the fixing by laser welding by situating the periphery of the cathode fixing surface part of the cathode fixing member of a cathode sleeve on the inside of the periphery of the fixing surface part of a cathode base. SOLUTION: A recessed part 22 is formed on one blocked end of a cylindrical cathode sleeve 21 formed of Ta, its alloy, or the like, and the part, except the periphery, of the bottom part 22a is formed as a flat protruding cathode fixing surface part 22b. A circular cathode base 3 formed of polar tungsten impregnated with an electron emitting material is fitted into the recessed part 22, and a fixing surface part 23b of the opposite side surface to an electron emitting surface 23a is fixed. A brazing filler metal layer 24 formed on the fixing surface part 23b is fused by the laser irradiation from the opened other end side of the sleeve 21, and the fixing surface part 23b is fixed to the fixing surface part 22b of the recessed part 22. Thus, the central part of the cathode fixing surface part of the recessed part 22 is prevented from being swollen with the peripheral part as a fulcrum, separated from the fixing surface part of the base 3 and fused at the time of laser irradiation as was conventionally performed.

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 used for an electron gun such as a color picture tube and a method for manufacturing the same.
The present invention relates to an electron gun structure and an electron tube.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for color picture tubes, large-sized color picture tubes, and high-definition display tubes having an increased number of scanning lines to improve the resolution. An impregnated cathode that can obtain electron emission with a larger current density than that of an oxide cathode is used as a cathode structure provided in an electron gun used in these electron tubes.

FIG. 7 is a partially cutaway front view showing the structure of a cathode assembly using a conventionally used impregnated cathode. The cathode sleeve 1 is in the form of a cylinder, for example Ta, Nb, M
It is formed of o, Re or an alloy thereof.
One end of the cathode sleeve 1 is closed to form a concave portion 2, and the bottom surface portion 2a of the concave portion 2 is entirely formed as the same flat surface.

A cathode substrate 3 is fitted and fixed inside the recess 2 of the cathode sleeve 1. The cathode substrate 3 is made of porous tungsten having a porosity of about 20% and is made of Bao, Al ₂
It has a circular shape impregnated with an electron emitting substance consisting of O ₃ and CaO, and one side face serves as an electron emitting face 3a for emitting the electron emitting substance, and the other side face forms a cathode base 3 and a recess 2. It is the fixing surface portion 3b. This fixed surface portion 3b
A brazing material layer 4 made of, for example, Ru-Mo is formed on the inner surface.

In the cathode substrate 3, the brazing material layer 4 is in contact with the bottom surface portion 2a of the concave portion 2 of the cathode sleeve 1, and the electron emitting surface 3a.
Are located outside the recess 2 and are fitted into the recess 2. The brazing material layer 4 is the cathode sleeve 1.
The bottom surface portion 2a of the recess 2 is melted by being irradiated with laser from the other open end of the recess portion 2 and then solidified to fix the fixing surface portion 3b of the cathode substrate 3 to the bottom surface portion 2a of the recess 2. A heater 5 is arranged inside the cathode sleeve 1 to heat the cathode substrate 3, and the heater 5 is fixed to a picture tube not shown. Outside the cathode sleeve 1, there is arranged a cathode supporting cylinder 6 having a diameter (outer diameter) larger than that of the cathode sleeve 1 and having a cylindrical body with both ends open, and one end of the cathode supporting cylinder 6 has a shoulder portion 6a. Are formed. The cathode support cylinder 6 is made of Kovar or the like.

Inside the cathode supporting cylinder 6, a plurality of cathode supporting bodies 7 are arranged in a distributed manner so as to surround the periphery of the cathode sleeve 1, and the cathode supporting body 7 is made of the same material as the cathode sleeve 1. There is. Each cathode support 7 is a cathode sleeve 1
Of the cathode support cylinder 6 is fixed to the shoulder 6a of the cathode support cylinder 6 by a method such as laser welding.
The other end is fixed to the other end peripheral surface of the cathode sleeve 1 by a method such as laser welding.

[0007]

The impregnated-type cathode assembly constructed as described above is small in size because power-saving operation is demanded, and the operating temperature of the impregnated-type cathode is high and the refractory metal is used as a component. Since many are used, the following problems arise in mounting the cathode.

That is, when the cathode substrate 3 is attached to the cathode sleeve 1, the cathode substrate 3 is fitted into the recess 2 of the cathode sleeve 1 and then the laser is irradiated from the other open end of the cathode sleeve 1. The cathode substrate 3 is fixed to the cathode sleeve 1 via the material layer 4. At the time of this fixing, there arises a problem that the bottom surface of the concave portion 2 of the cathode sleeve 1 is melted and a hole is opened, resulting in a problem that the yield in manufacturing the impregnated cathode structure is extremely deteriorated.

The method of fixing the cathode substrate 3 to the cathode sleeve 1 by laser welding is carried out by the method described below. First, as shown in the cross-sectional layer of FIG. 8, the cathode substrate 3 is placed on the upper end of the die 11 with the brazing material layer 4 facing upward.
Is inserted from below into the hole 14 formed in the table 13. Next, with the concave portion 2 facing downward, the cathode sleeve 1
Is inserted into the hole 14 formed in the table 13 from above, the concave portion 2 of the cathode sleeve 1 is fitted into the cathode substrate 3 placed on the upper end of the die 11. As a result, the bottom surface 2a of the recess 2 contacts the brazing material layer 4 of the cathode substrate 3.
Here, the diameter of the bottom surface portion 2a of the recess 2 is set to be larger than the diameter of the fixing surface portion 3b (the brazing material layer 4) of the cathode substrate 3.

Next, the press punch 12 is inserted into the hole 14 formed in the table 13 from above and into the cathode sleeve 2 from the open end of the other end, and the recess 2 of the cathode sleeve 1 is formed at the lower end surface 12a. The bottom surface 2a of the above is pressed from above and brought into pressure contact with the brazing material 4 of the cathode substrate 3. This is to make the bottom surface portion 2a of the recess 2 and the cathode substrate 3 more positively contact with each other in order to improve the weldability. Presser punch 1
2 has a hole 12b through which a laser passes.
Is formed. The lower end surface portion 12a of the pressing punch 12 has a diameter larger than that of the bottom surface portion 2a of the recess 2 of the cathode sleeve 1, and is protruded from the bottom surface portion 2a of the recess 2 to be in contact therewith.

Next, the laser beam L is irradiated through the holding punch 12 from the hole 12b to the bottom surface 2a of the recess 2 of the cathode sleeve 1. As a result, the brazing material layer 4 is heated and melted through the bottom surface portion 2a of the recess 2 of the cathode sleeve 1 to be solidified, and the bottom surface portion 2a of the recess 2 and the cathode substrate 3 are fixed via the brazing material layer 4.

However, when this welding is actually performed, the bottom surface of the recess 2 of the cathode sleeve 1 is melted by the laser to form a hole, and the bottom surface 2a of the recess 2 of the cathode sleeve 1 and the cathode substrate 3 cannot be welded. As a result, many defective products occurred. The cause of occurrence of such a situation is considered as follows. That is, as shown in the partially enlarged sectional view of FIG. 9, the lower end surface portion 12a of the pressing punch 12 contacts the bottom surface portion 2a of the recess 2 of the cathode sleeve 1 only at the peripheral portion of the bottom surface portion 2a. Therefore, the central portion (near the welded portion) of the bottom surface portion 2a of the concave portion 2 of the cathode sleeve 1 swells and bulges with the peripheral portion of the cathode substrate 2 as a fulcrum, and as a result, the cathode sleeve 1
The bottom surface portion 2a of the concave portion 2 is separated from the brazing material layer 4 (fixing surface portion 3b) of the cathode substrate 2 to form a gap therebetween.

When a laser beam is radiated with a gap between the bottom surface 2a of the recess 2 of the cathode sleeve 1 and the brazing material layer 4 (fixing surface 3b) of the cathode substrate 3, the laser beam is emitted. Before reaching the brazing material layer 4 of No. 3, the bottom surface 2a of the recess 2 is struck and the bottom surface 2a of the recess 2 of the cathode sleeve 1 is melted by the energy of the laser beam to form a hole,
The cathode substrate 3 cannot be fixed well to the bottom surface 2a of the recess 2.

The invention of the present application has been made in view of the above circumstances, and when fixing the cathode fixing member provided with the cathode base on the cathode sleeve, it is possible to perform good fixing with high yield without fusing the cathode fixing member. It is an object of the present invention to provide an impregnated-type cathode structure capable of achieving the above and a method for manufacturing the same. Another object of the present invention is to provide an electron gun structure and an electron tube with high reliability.

[0015]

An impregnated-type cathode assembly according to claim 1 of the present application is a cathode sleeve, a cathode fixing member provided on the cathode sleeve and having a cathode fixing surface portion, and a fixing surface portion impregnated with an electron emitting substance. And a cathode base fixed to the cathode fixing surface of the cathode fixing member, and the peripheral edge of the cathode fixing surface of the cathode fixing member is located inside the peripheral edge of the fixing surface of the cathode base. It is characterized by being

According to this structure, when the fixing surface portion of the cathode substrate is fixed to the cathode fixing surface portion of the cathode fixing member provided on the cathode sleeve by a method such as laser welding, the cathode substrate and the cathode fixing member are combined. When a pressing force is applied to the cathode fixing member in order to bring them into close contact, the entire fixing surface portion of the cathode fixing member is located in a portion surrounded by the peripheral edge of the fixing surface portion of the cathode substrate and contacts the fixing surface portion of the cathode substrate. .

Therefore, in the cathode fixing surface portion of the cathode fixing member, the central portion bulges around the peripheral portion of the fixing surface portion of the cathode substrate as a fulcrum, and the situation where the cathode fixing surface portion is separated from the fixing surface portion of the cathode substrate does not occur. Therefore, when the fixing surface portion of the cathode fixing member is irradiated with laser light for welding, the cathode fixing surface portion of the cathode fixing member is securely fixed to the fixing surface portion of the cathode base without being fused.

The impregnated-type cathode assembly according to a second aspect of the present invention has a tubular shape and one end is closed to form the closed portion as a recess, and the bottom surface of the recess except the peripheral portion is convex. A cathode sleeve formed as a fixed cathode fixing surface portion; and a cathode base having a fixing surface portion impregnated with an electron emissive substance, the fixing surface portion being fixed to the convex cathode fixing surface portion of the cathode sleeve. The peripheral edge of the convex cathode fixing surface portion is located inside the peripheral edge of the fixing surface portion of the cathode substrate.

According to this structure, when the fixing surface portion of the cathode base is fixed to the bottom surface of the concave portion formed at the one end closed portion of the cathode sleeve by a method such as laser welding, the concave portion of the cathode base and the concave portion of the cathode sleeve are formed. When a pressing force is applied to the cathode sleeve in order to bring them into close contact with each other in combination, the entire convex cathode fixing surface formed on the bottom surface of the recess of the cathode sleeve excluding its peripheral edge is fixed to the cathode substrate. It is located in the portion surrounded by the peripheral edge of the surface portion and contacts the fixed surface portion of the cathode substrate. That is, since the convex cathode fixing surface portion is formed on the bottom surface of the concave portion of the cathode sleeve, the peripheral edge portion of this bottom surface portion does not contact the peripheral portion of the fixing surface portion of the cathode substrate, and only the convex cathode fixing surface portion is formed. It contacts the fixed surface portion of the cathode substrate.

Therefore, the convex cathode fixing surface portion of the concave portion of the cathode sleeve does not bulge in the central portion with the peripheral portion of the fixing surface portion of the cathode substrate as a fulcrum and separate from the fixing surface portion of the cathode substrate. Therefore, when the convex cathode fixing surface portion of the concave portion of the cathode sleeve is irradiated with a laser for welding, the convex cathode fixing surface portion of the cathode sleeve is securely fused to the fixing surface portion of the cathode substrate without being fused.

The impregnated-type cathode assembly according to a third aspect of the present invention is a tubular cathode sleeve having both ends opened, and a cup-shaped cathode sleeve fitted into one end of the cathode sleeve and fixed to the cathode sleeve. And a cathode fixing member in which a portion other than a peripheral edge portion of the bottom surface portion is formed as a convex cathode fixing surface portion, and a fixing surface portion impregnated with an electron emitting substance, and the fixing surface portion is the cathode fixing surface portion of the cup-shaped cathode fixing member. The cup-shaped cathode fixing member has a cathode base surface fixed to the cathode base surface, and the cathode base surface of the cup-shaped cathode base member has a peripheral edge located inside the peripheral edge of the base surface. For example, since the cup-shaped cathode fixing member is separate from the cathode sleeve, the convex cathode fixing surface portion having a complicated shape can be easily formed.

The method of manufacturing the impregnated cathode structure according to claim 4 is
The cathode substrate is placed on the punch so that its fixed surface portion is located on the upper side, and then the tubular substrate is formed and one end is closed to form this closed portion as a concave portion, and the peripheral edge of the bottom surface portion of this concave portion. A cathode sleeve having a portion excluding the entire portion formed as a convex cathode fixing surface portion is prepared, and the cathode sleeve is arranged with the convex cathode fixing surface portion facing downward, and the convex cathode fixing surface portion is formed on the cathode substrate. Abut
Then, a holding punch having a hole for passing a laser is inserted into the inside of the cathode sleeve, and the convex cathode fixing surface portion of the cathode sleeve is pressed by the lower end portion thereof, and then the laser is passed through the punch for passing the laser. The cathode base is fixed to the cathode fixing surface by irradiating the cathode fixing surface of the cathode sleeve through the hole.

According to this manufacturing method, only the convex cathode fixing surface portion is brought into contact with the fixing surface portion of the cathode substrate without contacting the peripheral edge portion of the bottom surface of the concave portion of the cathode sleeve with the peripheral portion of the fixing surface portion of the cathode substrate. The step of irradiating the convex cathode fixing surface portion of the cathode sleeve with laser light to fix the convex cathode fixing surface portion of the cathode sleeve and the fixing surface portion of the cathode substrate can be favorably carried out.

An electron gun assembly according to a fifth aspect is characterized by using the impregnated cathode assembly according to any one of the first to third aspects. According to this configuration, a highly reliable electron gun structure can be obtained.

An electron tube according to a sixth aspect is characterized by using the electron gun structure according to the fifth aspect. According to this configuration, a highly reliable electron tube can be obtained.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described with reference to FIGS. 1 is a partially cutaway front view showing the structure of the impregnated-type cathode assembly according to the first embodiment, FIG. 2 is an enlarged cross-sectional view showing a cathode base fixing portion in FIG. 1, and FIG. 3 is a cross-sectional view showing a method for fixing the cathode base of the impregnated-type cathode structure of the embodiment, and FIG. 4 is an enlarged cross-sectional view showing the cathode base fixing portion in the method shown in FIG.

The cathode sleeve 21 has a cylindrical body, and Ta,
It is formed of Nb, Mo, Re or an alloy thereof. One end of the cathode sleeve 21 is closed to form a recess 22.
The bottom surface 22a of the concave portion 22 is formed as a convex cathode fixing surface portion 22b which is flat except for the entire peripheral portion.

The cathode substrate 3 is fitted and fixed inside the recess 22 of the cathode sleeve 21. The cathode substrate 3 is made of porous tungsten with a porosity of about 20% and is made of Ao, A
It has a circular shape impregnated with an electron emitting substance consisting of l ₂ O ₃ and CaO, and one side face is an electron emitting face 23a for emitting the electron emitting substance, and the other side face is a recess 22 of the cathode sleeve 21. And a fixed surface portion 23b.
The brazing material layer 2 made of Ru-Mo is formed on the fixing surface portion 23b.
4 are formed.

Then, as shown in FIG. 2, in the cathode substrate 23, the brazing material layer 24 is in contact with the convex cathode fixing surface portion 22b of the concave portion 22 of the cathode sleeve 21, and the electron emitting surface 23a is located outside the concave portion 22. It is positioned and fitted in the recess 22. The brazing material layer 24 is melted and solidified by irradiating the bottom surface portion 22a of the concave portion 22 with a laser from the opened other end side of the cathode sleeve 21, and then solidified to fix the fixing surface portion 23b of the cathode substrate 23 to the bottom surface of the concave portion 22. It is fixed to the convex cathode fixing surface portion 22b of the portion 22a. The electron emission surface 23a of the cathode substrate 23 is located on the same plane as the tip of the open portion of the recess 22, or so as to project slightly outward. In this embodiment, the electron emission surface 23a of the cathode substrate 23 projects slightly outward from the open end of the recess 22.

Inside the cathode sleeve 21, a cathode substrate 23 is provided.
A heater 25 is arranged to heat the display device, and the heater 25 is fixed to a picture tube not shown. Outside the cathode sleeve 21, a cathode support cylinder 26 having a diameter (outer diameter) larger than that of the cathode sleeve 21 and formed of a cylindrical body with both ends open is arranged. One end of the cathode support cylinder 26 has a shoulder portion 26 a. Are formed. The cathode support cylinder 26 is made of Kovar.

Inside the cathode supporting cylinder 26, the cathode sleeve 2 is provided.
A plurality of cathode supports 27 are arranged in a dispersed manner around the circumference of 1, and the cathode supports 27 are made of the same material as the cathode sleeve 21. Each cathode support 27 extends in the axial direction of the cathode sleeve 21, one end thereof is fixed to a shoulder portion 26 a of the cathode support cylinder 26 by a method such as laser welding, and the other end thereof is a peripheral surface of the other end of the cathode sleeve 21. It is fixed by a method such as laser welding.

The method of fixing the cathode substrate 23 to the cathode sleeve 21 by laser welding is performed by the following steps. First, as shown in FIG. 3, the cathode substrate 23 is placed on the upper end of the die 31 with the brazing material layer 24 facing upward, and the die 31 is inserted into the holes 34 formed in the table 33 from the lower side. Next, the cathode sleeve 21 is inserted into the hole 34 formed in the table 33 from above with the concave portion 22 and the convex cathode fixing surface portion 22b, which are one end portions, facing downward. Then, the concave portion 22 of the cathode sleeve 21 fits into the cathode substrate 23 placed on the upper end of the die 31. As a result, the entire convex cathode fixing surface portion 22b of the concave portion 22 is located in the portion surrounded by the periphery of the fixing surface portion 23b of the cathode substrate 23 and contacts the brazing material layer 24. That is, the peripheral edge portion of the bottom surface portion 22a of the concave portion 22 does not contact the peripheral edge portion of the fixing surface portion 23b of the cathode substrate 23, and only the convex cathode fixing surface portion 22b contacts the fixing surface portion 23b of the cathode substrate 23.

Next, the pressing punch 32 is inserted into the hole 34 formed in the table 33 from above and into the cathode sleeve 21 from the other end open portion, and the lower end surface portion 32a.
Then, the bottom surface portion 22a of the concave portion 22 of the cathode sleeve 21 is pressed from above to bring the convex cathode fixing surface portion 22b into pressure contact with the brazing material layer 24 of the cathode substrate 23. This is to improve the weldability between the convex cathode fixing surface portion 22b of the concave portion 22 and the cathode substrate 23. A hole portion 32b through which a laser passes is formed in a lower end surface portion 32a of the pressing punch 32. The lower end surface portion 32a of the pressing punch 32 has a larger diameter than the bottom surface portion 22a of the recess 22 of the cathode sleeve 21,
The bottom surface portion 22a of the slab protrudes and abuts. The convex cathode fixing surface portion 22b of the cathode sleeve 21 is formed by the conventional cathode substrate 23.
There is no situation in which the central portion bulges around the peripheral portion of the fixing surface portion 23b as a fulcrum and separates from the fixing surface portion 23b of the cathode substrate 23.

Next, the laser light L is irradiated through the holding punch 32 through the hole 32b to the convex cathode fixing surface portion 22b of the concave portion 22 of the cathode sleeve 21. As a result, the brazing material layer 24 is heated and melted through the convex cathode fixing surface portion 22b of the concave portion 22 of the cathode sleeve 21 to be solidified,
As shown in FIG. 4, the entire convex cathode fixing surface portion 22b of the concave portion 22 and the cathode substrate 23 are surely fixed to each other. In this case, the convex cathode fixing surface portion 22b of the cathode sleeve 21 is not blown by the laser because the central portion does not bulge and is not separated from the fixing surface portion 23b of the cathode substrate 23.

The cathode sleeve 21 used in the present invention.
Can be manufactured, for example, as follows. First, as the cathode leaf 21, a disk is punched out from, for example, a Ta plate having a thickness of 0.025 mm, and thereafter, the drawing process is repeated to perform processing to a predetermined outer diameter. Next, edge cutting processing is performed so that the entire length of the cathode sleeve 21 becomes a predetermined size, and then the closed portion of the cathode sleeve 21 is subjected to molding processing to form the concave portion 22 and the convex cathode fixing surface portion 22b. When the cathode sleeve 21 made of T a is repeatedly drawn, the cathode sleeve 2
It is preferable to anneal in the intermediate step because work hardening easily occurs in No. 1 and breakage easily occurs.

Although the material of the cathode sleeve 21 is Τa in this embodiment, it is not limited to this, and Nb and Τa-Nb alloy, W-Ta alloy or Mo, Re and Re-Mo alloy can be adopted. . This Nb and Τa-
Nb alloys and W-Ta alloys can be manufactured almost in the same manner as Ta, and welding can be performed in the same manner. Further, in the case of Mo, Re and Re-Mo alloy, it can be formed by heating during sleeve processing. Welding was performed with Re and Re-Mo alloys rather than T
It is less likely to be embrittled at high temperature than a, and good welding is possible.

The cathode assembly thus constructed has the following features. Specifically, the impregnated-type cathode structure of this embodiment has a tubular shape and one end is closed to form this closed part as a recess 22, and the peripheral edge of the bottom 22 a of this recess 22. A portion other than the entire portion is formed as the convex cathode fixing surface portion 22b, and the cathode sleeve 21 is fixed with the electron emitting substance.
and the cathode base 23 fixed to the cathode fixing surface 22b of the recess 22 of the cathode sleeve 21, and the peripheral edge of the convex cathode fixing surface 22b of the cathode sleeve 21 is It is configured to be located inside the peripheral edge of the fixing surface portion 23b.

According to this structure, the convex cathode fixing surface portion 22 of the concave portion 22 formed at the one end closed portion of the cathode sleeve 21.
When the fixing surface portion 23b of the cathode base body 23 is fixed to b by a method such as laser welding, the cathode base body 23 and the concave portion 22 of the cathode sleeve 21 are combined with each other so as to bring them into close contact with each other. When applying pressure, the bottom surface 22a of the recess 22 of the cathode sleeve 21
Convex cathode fixing surface portion 2 formed in the portion excluding the peripheral portion of the
The entire 2b is located in a portion surrounded by the periphery of the fixing surface portion 23b of the cathode substrate 23, and is fixed to the fixing surface portion 23b of the cathode substrate 23.
Touch That is, since the convex cathode fixing surface portion 22b is formed on the bottom surface portion 22a of the concave portion 22 of the cathode sleeve 21, the peripheral edge portion of this bottom surface portion 22a is the cathode substrate 23.
Of the cathode base 23 without contacting the peripheral edge of the fixing surface 23b of the cathode base 23.
touch b.

Therefore, the convex cathode fixing surface portion 22b of the concave portion 22 of the cathode sleeve 21 to which the pressing force is applied swells in the central portion with the peripheral portion of the fixing surface portion 23b of the cathode substrate 23 as a fulcrum, and the fixing surface portion of the cathode substrate 23. The situation of leaving from 23b does not occur. When the convex cathode fixing surface portion 22b of the cathode sleeve 21 is irradiated with laser light for welding, the convex cathode fixing surface portion 22 by the laser light is irradiated.
It is possible to securely fix the entire convex cathode fixing surface portion 22b to the fixing surface portion 23b of the cathode substrate 23 without melting of the b.

Here, an example of specific dimensions will be described. The diameter of the cathode substrate 23 is 1.3 mm and the height (thickness) is 0.4.
mm, brazing material thickness 0.04 mm. Inner diameter of cathode sleeve 21: 1.65 mm, plate thickness: 0.02 mm, convex cathode fixing surface portion 22b
Has a diameter of 1 mm and a height of 0.35 mm.

By the way, in the above-described embodiment, the shape of the recess 22 of the cathode sleeve 21 is shown as a shape in which there is a gap between the inner surface of the cathode sleeve 21 and the outer surface of the recess 22. The shape of the recess 22 is not limited to this.

Next, a second embodiment will be described. FIG.
FIG. 6 is a partially cutaway front view showing the structure of the impregnated-type cathode assembly according to the second embodiment. 5, the same parts as those in FIG. 1 are designated by the same reference numerals.

As shown in this embodiment, even if the inner surface of the cathode sleeve 21 and the outer surface of the concave portion 22 are in contact with each other without a gap, the same effect as in the above-described embodiments can be obtained. It is possible.

Next, a third embodiment will be described. FIG.
[Fig. 6] is a partially cutaway front view showing a structure of an impregnated-type cathode assembly according to a third embodiment. 6, the same parts as those in FIG. 1 are designated by the same reference numerals. In this embodiment, a cathode sleeve 21A having a cylindrical shape with both ends open and a cup-shaped cathode sleeve 21A which is fitted into one end of the cathode sleeve 21A by a method such as laser welding.
The cup-shaped cathode fixing member 41 fixed to A and having a portion except the entire peripheral portion of the bottom surface portion 41a formed as a convex cathode fixing surface portion 41b is used, and the cathode fixing surface portion 41b of the cup-shaped cathode fixing member 41 is The peripheral edge thereof is located inside the peripheral edge of the fixing surface portion 23b of the cathode substrate 23. According to the structure of this impregnated cathode structure, the cup-shaped cathode fixing member is separate from the cathode sleeve, so that the convex-shaped cathode fixing surface portion having a complicated shape can be easily formed.

The invention of the present application is not limited to the above-described embodiments, but can be implemented in various modified forms. According to the first aspect of the invention, the cathode fixing surface portion of the cathode fixing member is intended to have a wide shape whose peripheral edge is located inside the peripheral edge of the fixing surface portion of the cathode substrate. That is, the impregnated cathode structure according to the first aspect of the present invention basically has a cathode sleeve, a cathode fixing member having a cathode fixing surface portion provided on the cathode sleeve, and a fixing surface portion impregnated with an electron emitting substance. Along with this fixing surface portion comprises a cathode substrate fixed to the cathode fixing surface portion of the cathode fixing member, the peripheral edge of the fixing surface portion of the cathode fixing member is located inside the peripheral edge of the fixing surface portion of the cathode substrate, Even if the concave portion of the cathode sleeve as shown in the first to third embodiments is not formed or the cup-shaped cathode fixing member is not used, as long as the relation between the fixing surface portion of the cathode base and the cathode fixing member is as described above. The shape is not limited at all.

According to the first aspect of the present invention, the fixing surface portion of the cathode substrate is fixed to the cathode fixing surface portion of the cathode fixing member provided on the cathode sleeve by laser welding or the like without being specified by the shape of the cathode fixing surface portion of the cathode fixing member. When fixing by the method, the entire cathode fixing surface of the cathode fixing member can be surely fixed to the fixing surface of the cathode substrate.

The impregnated cathode structure shown in the first to third embodiments is used as an electron gun structure which has been conventionally used.
Further, when the above-mentioned electron gun assembly was used for a conventionally used color picture tube, a highly reliable electron gun assembly and electron tube could be obtained.

[0048]

According to the impregnated cathode structure of the first aspect of the invention, when the fixing surface portion of the cathode substrate is fixed to the cathode fixing surface portion of the cathode fixing member provided on the cathode sleeve by a method such as laser welding, When a pressing force is applied to the cathode fixing member to combine the cathode substrate and the cathode fixing member to bring them into close contact with each other, the entire fixing surface portion of the cathode fixing member becomes a portion surrounded by the periphery of the fixing surface portion of the cathode substrate. Positioned and in contact with the fixed surface portion of the cathode substrate. For this reason, the cathode fixing surface portion of the cathode fixing member does not cause a situation in which the central portion bulges with the peripheral portion of the fixing surface portion of the cathode base as a fulcrum and separates from the fixing surface portion of the cathode base. Therefore, when the cathode substrate is fixed to the cathode fixing member of the cathode sleeve, good welding can be performed with a high yield without fusing the cathode fixing member.

According to the impregnated cathode structure of the second aspect of the invention, when the fixing surface portion of the cathode substrate is fixed to the bottom surface of the recess formed in the one end closed portion of the cathode sleeve by a method such as laser welding, When a pressing force is applied to the cathode sleeve in order to bring the base body and the recessed portion of the cathode sleeve into close contact with each other and to bring them into close contact, a convex cathode fixing surface portion formed on the bottom surface portion of the recessed portion of the cathode sleeve excluding its peripheral portion Is located in a portion surrounded by the peripheral edge of the fixing surface portion of the cathode substrate and contacts the fixing surface portion of the cathode substrate. For this reason, the peripheral edge portion of the bottom surface of the concave portion of the cathode sleeve does not come into contact with the peripheral edge portion of the fixing surface portion of the cathode substrate, and the cathode fixing surface portion of the concave portion does not swell and separate from the fixing surface portion of the cathode substrate. Therefore, when the cathode substrate is welded and fixed to the recess of the cathode sleeve, the bottom surface of the recess of the cathode sleeve is not melted and good welding can be performed with high yield.

According to the impregnated cathode structure of the third aspect of the present invention, since the cathode fixing member is separate from the cathode sleeve, the convex cathode fixing surface portion having a complicated shape can be easily formed. be able to.

According to the manufacturing method of the fourth aspect of the present invention, the peripheral edge portion of the bottom surface of the recess of the cathode sleeve does not contact the peripheral edge portion of the fixing surface portion of the cathode substrate, and only the convex cathode fixing surface portion of the cathode substrate is formed. The step of contacting the fixing surface portion and irradiating the convex cathode fixing surface portion of the concave portion of the cathode sleeve with a laser beam to fix the convex cathode fixing surface portion of the concave portion of the cathode sleeve and the fixing surface portion of the cathode substrate are well performed. can do.

According to the electron gun assembly of the fifth aspect, by using the impregnated cathode assembly according to any one of the first to third aspects, a highly reliable electron gun assembly can be obtained. it can. According to the electron tube of the invention of claim 6, by using the electron gun structure of claim 5, a highly reliable electron tube can be obtained.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an impregnated-type cathode assembly according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a cathode base fixing portion in the impregnated-type cathode assembly according to the same embodiment.

FIG. 3 is a cross-sectional view showing a method of fixing a cathode substrate of an impregnated-type cathode assembly in the same embodiment.

FIG. 4 is an enlarged cross-sectional view showing a cathode base fixed portion in the method shown in FIG.

FIG. 5 is a partially cutaway front view showing an impregnated-type cathode assembly according to a second embodiment of the present invention.

FIG. 6 is a partially cutaway front view showing an impregnated-type cathode assembly according to a third embodiment of the present invention.

FIG. 7 is a partially cutaway front view showing an impregnated-type cathode assembly in a conventional form.

FIG. 8 is a cross-sectional view showing a method of fixing a cathode substrate of an impregnated-type cathode assembly in a conventional form.

9 is an enlarged cross-sectional view showing a cathode base fixed portion in the method shown in FIG.

[Explanation of symbols]

 21 ... Cathode sleeve, 22 ... Recessed portion (cathode fixing member), 22b ... Convex cathode fixing surface portion, 23 ... Cathode substrate, 23b ... Fixing surface portion, 26 ... Cathode support cylinder, 27 ... Cathode support body, 31 ... Die, 32 ... Punch.

Front page continuation (72) Inventor Yukio Komatsubara 50 Kamamiyobe, Yobu Ward, Himeji City, Hyogo Prefecture

Claims (6)

[Claims] 1. A cathode sleeve, a cathode fixing member which is provided on the cathode sleeve and has a cathode fixing surface portion, and a fixing surface portion which is impregnated with an electron emitting substance and which is fixed to the cathode fixing surface portion of the cathode fixing member. And a cathode fixing surface part of the cathode fixing member,
An impregnated-type cathode assembly, wherein the impregnated-type cathode assembly is located inside a peripheral edge of a fixing surface portion of the cathode substrate. 2. A tubular shape, one end of which is closed to form the closed portion as a recess, and a portion of the bottom surface of the recess other than the peripheral edge portion is formed as a convex cathode fixing surface portion. A cathode sleeve, and a cathode substrate having a fixing surface portion impregnated with an electron emissive material and the fixing surface portion being fixed to the convex cathode fixing surface portion of the cathode sleeve, the convex cathode fixing surface portion of the cathode sleeve,
An impregnated-type cathode assembly, wherein the impregnated-type cathode assembly is located inside a peripheral edge of a fixing surface portion of the cathode substrate. 3. A cathode sleeve having a tubular shape with both ends open, and a cup-shaped cathode sleeve fitted into one end of the cathode sleeve and fixed to the cathode sleeve. A cathode fixing member whose excluding portion is formed as a convex cathode fixing surface portion, and a cathode having a fixing surface portion impregnated with an electron emissive substance, and the fixing surface portion being bonded and fixed to the convex cathode fixing surface portion of the cup-shaped cathode fixing member. An impregnated-type cathode assembly comprising a base and a convex cathode fixing surface portion of the cup-shaped cathode fixing member is located inside a peripheral edge of the fixing surface portion of the cathode substrate. 4. A cathode substrate having a fixing surface portion is placed on a punch so that the fixing surface portion is located on the upper side, and then is formed into a tubular shape and one end portion is closed to form this closed portion as a concave portion. At the same time, prepare a cathode sleeve in which a portion except the entire peripheral portion of the bottom surface of the concave portion is formed as a convex cathode fixing surface portion, and the cathode sleeve is arranged with the concave portion on the lower side, and the convex cathode fixing surface is formed. The surface portion is brought into contact with the fixing surface portion of the cathode substrate, and then a punch having a hole for passing a laser is inserted into the inside of the cathode sleeve, and the lower end of the punch presses the convex cathode fixing surface portion of the cathode sleeve. After that, the laser is irradiated to the cathode fixing surface portion of the cathode sleeve through the laser passage hole of the punch to fix the cathode substrate to the cathode fixing surface portion. Method for manufacturing impregnated cathode assembly according to claim 1. 5. An electron gun assembly comprising the impregnated cathode assembly according to any one of claims 1 to 3. 6. An electron tube using the electron gun according to claim 5.