JPS62154535A - Magnetron cathode structure - Google Patents

Abstract

PURPOSE:To prevent the occurrence for a leak current from a getter material, by installing a recessed part, which is not opposed to a magnetic pole and the anode, in an upper end shield of a magnetron cathode structural. CONSTITUTION:In an upper end shield 2, there is provided with a recessed part 2 at the opposite side to the filament fixed side, and a getter material 6 is tightly attached to the inside of a recessed part 2 so as not to oppose a magnetic pole 9 and a vane 7. According to such like constitution, the getter material 6 absorbs a large quantity of gas, and a surface state becomes rough, coming into the state that cold emission is liable to go out, whereby even if high voltage is impressed between the cathode and the anode, the getter material is not opposed to the magnetic pole 9 and the vane 7 so that field strength among the getter material 6, magnetic pole 9 and the vane 7 becomes very weakened, thus a leak current from the getter material 6 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetron cathode assembly, and more particularly to a magnetron cathode assembly that prevents leakage current from a getter material and improves reliability.

[Background of the invention]

Figure 1 is a cross-sectional diagram of the main parts showing an example of the vicinity of a conventionally used magnetron cathode structure.
No. 457. In the figure, a filament 1 disposed at the center of the tube axis of the magnetron is connected to an upper end shield 2 that prevents thermoelectrons from deviating from the action space 1a.
and a lower end shield 3, and a center lead 4 and a side lead 5 are connected to the upper end shield 2 and lower end shield 3, respectively.
A getter material is attached to the opposite side of the upper end shield 2 from the filament fixing side by welding or by applying a powder and fixing it by sintering. Further, around the filament 1, a plurality of vanes 7 forming a cavity resonator are connected every other vane by a strap ring 8 and arranged coaxially with the filament 1. Further, a pair of magnets 14 are provided at the upper and lower ends of the vane 7 at a distance from the vane 7 to supply magnetic flux to the working space 1a between the vane 7 and the filament 1.
9.10 is installed.

In a magnetron with such a configuration.

The getter material 6 attached to the upper end shield 2 has the role of absorbing gas generated within the tube during operation of the magnetron. However, if the magnetron is operated for a long time and the getter material 6 absorbs a large amount of gas, the surface condition of the getter material 6 becomes rough. As the surface condition of the getter material 6 becomes rough, cold emissions are more likely to be emitted from the getter material 6, and when a high quasi-pressure is applied during magnetron operation, between the getter material 6 and the magnetic pole 9 and between the getter material 6 and the vane 7. A leakage current flows between the two. When this leakage current becomes large, the leakage current is caused by the surge voltage that occurs when high voltage is applied and the moderating voltage until the magnetron operates stably, and discharge occurs between the cathode and the anode, causing damage to microwave oven diodes, etc. It may cause damage.

[Purpose of invention]

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and its object is to provide a magnetron cathode structure that prevents leakage current from the getter material.

[Summary of the invention]

A recess that does not face the magnetic pole and anode is provided in the upper end shield of the magnetron cathode assembly, and a getter material is housed in this recess.

[Embodiments of the invention]

Next, embodiments of the present invention will be described in detail using the drawings.

FIG. 2 is a cross-sectional configuration diagram of essential parts showing an embodiment of the magnetron cathode assembly and its surroundings according to the present invention. In the same figure, 5th
The same parts as those in the figures are given the same reference numerals and the explanation thereof will be omitted.

In FIG. 2, the upper end shield 2 is provided with four parts 2a on the side opposite to the filament fixed side, and the getter material 6 is fixed inside the recess 2 so as not to face the magnetic pole 9 and the vane 7.

According to such a configuration, the getter material 6 absorbs a large amount of gas, and the surface condition becomes rough and cold emission is likely to occur, and even if a high voltage is applied between the cathode and the anode, the getter material 6 Since the magnetic pole 9 and the vane 7 do not face each other, the electric field strength between the getter material 6 and the magnetic pole 9 and the vane 7 is extremely weak, which has the effect of preventing leakage current.

Note that the shape of the recess provided in the upper end shield 2 is not limited to the shape of this embodiment, and as long as the shape does not face the magnetic pole 9 and the vane 7, the same effect can be obtained.

FIG. 3 is a sectional view of the main parts around the cathode structure showing another embodiment of the present invention, and in the same figure, the upper end shield 2
A getter storage component 11 having a recess that does not face the magnetic pole 9 and the vane 7 is attached to the getter storage component 11.
The getter material 6 is attached inside the recess so as not to face the magnetic pole 9 and the vane 7. Even in such a configuration, the same effects as described above can be obtained. Further, as described above, the shape of the getter storage component 11 is not limited to the shape of this embodiment.

〔Effect of the invention〕

As explained above, the magnetron cathode structure according to the present invention has the advantage that even if the getter material absorbs a large amount of gas due to the operation of the magnetron, leakage current from the getter material can be prevented, and as a result, a highly reliable magnetron can be obtained. It has a great effect.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of essential parts for explaining an example of the vicinity of a conventional magnetron cathode structure, FIG. 2 is a cross-sectional view of main parts showing an example of the magnetron cathode structure according to the present invention, and FIG. FIG. 7 is a sectional view of a main part showing another embodiment.

Claims (1)

[Claims] The upper and lower ends of the filament are fixed to the upper end shield fixed to the center lead and the lower end shield fixed to the side leads, and a magnetron cathode with a getter material installed on the side opposite to the filament fixed side of the upper end shield. A magnetron cathode structure characterized in that a getter material is fixed inside a recess provided in an upper end shield.