JPS5854769Y2 - electron tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron tube equipped with an electron gun having a plate metal electrode supported and insulated by a ceramic support.

A traveling wave tube is a typical example of an electron tube that forms an electron gun consisting of a plate-shaped metal electrode and a ceramic pillar.

FIG. 1 shows a cross section of a conventional traveling wave tube 1, particularly an electron gun section 2, and FIG. 2 shows a three-dimensional view of the electron gun section 2.

In FIG. 1, the electron gun unit 2 has three circular holes drilled at the center of the electrodes 3, 4, and 5.6, which are equipped with a disk-shaped electrode and a disk-shaped support. Cylindrical ceramic pillar 7
The main components of the electron gun are fixed by brazing, the metal vacuum container 9, each electrode 3, 4, 5.6, each lead wire 13, 14, 17, 18 led from the heater 23, and an introduction connected to the lead wire. The stem 10 is provided with a wire 11 and is brazed to the inner peripheral surface of the vacuum vessel 9 to form a part of the vacuum vessel.

An exhaust pipe 15 is brazed to the stem 10 for exhausting air during the manufacturing stage of the traveling wave tube.

An ion stopper electrode 3 is disposed in a circular hole at the center of a metal disc-shaped electrode support and is made by brazing a cylindrical electrode having the same inner diameter as the circular hole.

A positive potential voltage that is normally about 100 V higher than the spiral slow wave circuit 19 is applied to the ion stopper electrode 3, and positive ions generated when the electron beam emitted from the cathode 20 collides with gas molecules in the traveling wave tube, It plays the role of preventing collision with the surface of the cathode 20 and suppressing destruction of the cathode surface.

Therefore, the ion-stopping electrode 3 is a disc-shaped ceramic 1
It is insulated from the metal vacuum container 9 via 2.

The accelerating electrode 4 is a metal disc with a circular hole in the center, or a cylindrical electrode is additionally joined to the circular hole in the center of the metal disc.

The focusing electrode 5 has a configuration in which another cylindrical electrode support is bonded to the outer circumference of the conical cylindrical electrode, and a disc-shaped electrode support is used to support these cylindrical electrodes. It has a shape that is brazed to the outer peripheral surface of a cylindrical electrode support.

The cathode electrode 6 is connected to the cathode 20 through a cylindrical electrode made of a material with low thermal conductivity that suppresses heat loss and maintains thermal and mechanical strength. It has a structure that is welded to a plate electrode.

These ion-stopping electrodes 3, accelerating electrodes 4, focusing electrodes 5, and cathode electrodes 6 are all made of disc-shaped electrode parts, and are arranged at equal intervals on concentric circles near the outer periphery of the disc-shaped electrodes and electrode supports. Three cylindrical ceramic pillars are placed in the drilled circular hole to maintain and fix the distance between the electrodes in the direction of the central axis and to maintain electrical insulation between the electrodes.

Lead wires 13, 14, 16, 17 for applying a traveling wave tube operating voltage are welded to the electrodes 3, 4, 5.6, respectively, and connected to the lead-in wire 11 of the stem 10 by welding.

The lead wire 13 drawn out from the ion stopper electrode 3 is connected to the electrode 4.
The lead-in wire 11 of the stem 10 is passed through the inside of the cylindrical insulating tube 8 inserted into the circular hole drilled at the same circumferential position of the disc-shaped electrode part and the disc-shaped electrode support of 5.6°. It is connected.

Like the lead wire 13 of the ion-stopping electrode 3, the lead wire 14 drawn out from the accelerating electrode 4 is also drawn out through the cylindrical insulating tube 22 inserted into the circular holes of the electrodes 5 and 6.

Since high voltage is applied to the ion stopper electrode 3 and the accelerating electrode 4, insulating tubes 8 and 22 are installed to prevent short-circuiting and insulation from other electrodes, and the material of the insulating tubes is high-purity alumina ceramic. I am using it.

The heater 18 has one end connected to the cathode electrode 6 and the other end connected to the lead-in wire 11 of the stem 10.

The getter 21 is for absorbing gas generated in the traveling wave tube after sealing the exhaust pipe 15 and suppressing an increase in the gas pressure in the tube, and is usually provided in an electron tube.

Since the conventional traveling wave tube electron gun section has a complicated structure as described above, there are several inherent problems.

In other words, the outer peripheral surfaces of the electrodes 3, 4, 5.6 are close to the inner peripheral surface of the metal vacuum container 9, and there is no space inside the vacuum container, and the shapes and dimensions of the electrodes 3, 4, 5.6 are is large,
Since the insulated tubes 8 and 22 are provided for the lead wires 13 and 14, the number of parts inside the pipe is large, and the total volume of the parts inside the pipe is also increased. There is also a large amount of gas released from the parts.

Therefore, an exhaust system with relatively large exhaust capacity was required.

Furthermore, even after the exhaust pipe 15 is sealed, there is a risk that gas may be released within the pipe, so it is necessary to provide the getter 21 with a large gas absorption capacity or to supplement it by providing a plurality of getters 21.

However, since there was no room in the tube, the getter 21
The supplementation of is naturally constrained.

In addition, dielectric breakdown is often caused by an electron avalanche phenomenon, so-called creeping discharge, caused by the synergistic effect of residual gas and electrons on the ceramic surface that supports and insulates opposing electrodes to which a high voltage is applied in a high vacuum. It had some observed drawbacks.

Such creeping discharge can be seen to some extent in the cylindrical ceramic pillar 7 and the insulating tubes 8 and 22 of the traveling wave tube electron gun. , 4, 5.6, a high voltage approximately 2 to 3 times the rated voltage is applied to forcibly generate creeping discharge, and its conditioning effect suppresses creeping discharge at standard operating voltage. A processing method has been applied.

However, in this high voltage treatment method, dirt, cracks, etc. on the surface of the insulating tube 8.22 often caused dielectric breakdown of the insulating tube itself.

As described above, defects caused by the complexity of the electrode structure of conventional traveling wave tube electron guns not only cause poor insulation of the traveling wave tube, but also have a large effect on its life.

An object of the present invention is to eliminate the above-mentioned drawbacks, provide an electron tube with a simple structure, and free from insulation defects such as creeping discharge.

The present invention relates to an electron tube equipped with an electron gun having a plurality of plate-shaped metal electrodes and a cylindrical ceramic column that extends through the outer periphery of the plate-shaped metal electrodes. It is characterized by using triangular electrodes and supporting the vicinity of each vertex with cylindrical ceramic columns.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 shows a three-dimensional view of the electron gun section of one embodiment of this invention.

The ion-stopping electrode 24 has a shape in which a cylindrical electrode having the same inner diameter as the circular hole is joined to a central circular hole of a triangular plate-shaped electrode support, and each vertex of the triangular plate-shaped electrode support has the same circumference. A circular cutout is made to form a surface.

Further, in the triangular plate-shaped electrode support body, circular holes for joining the cylindrical ceramic supports 7 are bored on the same circumference near each vertex.

The accelerating electrode 25 is made of a triangular plate-shaped pole, and the shape of the outer circumferential surface of the apex portion and the circular hole connecting the cylindrical ceramic support 7 are the same shape as the ion-stopping electrode 24 .

The focusing electrode 26 and the cathode electrode 27 are obtained by changing only the disc-shaped electrode support of the focusing electrode 5 and the cathode electrode 6 shown in FIG. The circular hole that connects the support column 7 has the same shape as the ion stopping electrode 24 and the accelerating electrode 25.

The above triangular electrodes 24, 25, 26, and 27 are arranged at appropriate intervals and are not bonded to the cylindrical ceramic pillar 73 to form an electron gun.

The lead wires 13, 14, 17, 18 are guided and connected to the introduction wire 11 of the stem 10, but the lead wires 13, 14 of the ion stopping electrode 24 and accelerating electrode 25 are insulated unlike the conventional tube shown in FIG. It is connected to the introduction line 11 through the gap between the rotten metal odor empty container 9 and each triangular electrode without inserting the tubes 8 and 22.

This has been made possible because the gap between the metal vacuum container 9 and the electrode has been greatly expanded by replacing the conventional disk-shaped electrode with a triangular plate-shaped electrode.

Therefore, the getter 21 does not need to be provided near the stem 10, and can be attached to the side surface of the focusing electrode 26, and a plurality of getters can be added.

Note that the present invention is also effective when some electrodes are made triangular, rather than all the electrode parts being made triangular as in the above-described embodiments.

As described above, by making the electrode shape and the electrode support shape triangular, it is possible to reduce the number of parts constituting the electron gun and to significantly reduce the total volume of the parts.

Furthermore, it is possible to reduce the amount of gas emitted from the electronic sharp parts components and to lower the exhaust resistance, making it possible to provide an electron tube having a more reliable high-vacuum electron gun.

Furthermore, by removing the insulating tubes 8 and 22, which were necessary in conventional tubes, creeping discharge between the electrodes is reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional traveling wave tube electron gun section, FIG. 2 is a three-dimensional view of a conventional traveling wave tube electron gun section, and FIG. 3 is a traveling wave tube of an embodiment of the present invention. FIG. 3 is a three-dimensional diagram showing an electron gun section. 1... Traveling wave tube, 2... Electron gun section, 3
...Disc-shaped ion stopping electrode, 4... Disc-shaped accelerating electrode, 5... Disc-shaped focusing electrode, 6...
... Disk-shaped cathode electrode, 7 ... Cylindrical ceramic support, 8, 22 ... Insulation tube, 9 ...
... Metal vacuum container, 10 ... Stem, 11.
... Lead wire, 12 ... Disc-shaped ceramic, 13, 14, 16, 17.18 ... Lead wire, 15 ... Exhaust pipe, 19. ...Spiral slow wave circuit, 20...Cathode, 21...
Getter, 23... Heater, 24... Triangular plate-shaped ion stop electrode, 25... Triangular plate-shaped accelerating electrode, 26... Triangular plate-shaped focusing electrode. , 27
...Triangular plate cathode electrode.

Claims (1)

[Scope of utility model registration request] 1. An electron tube comprising an electron gun having a structure in which the outer periphery of a plurality of plate-shaped metal electrodes is supported by cylindrical ceramic supports, characterized in that the plate-shaped metal electrodes have a triangular shape.