KR19980023771A - Pole piece structure of magnetron - Google Patents

Abstract

The present invention provides a magnetron pole piece structure in which a magnetic field is suppressed around the ends of upper and lower pole pieces for minimizing unnecessary harmonics generated during operation of the magnetron in a magnetron generating high frequency by the action of an electric field and a magnetic field. To the filament is formed in the center of the magnetron and the hot electrons are released by the heating action, a plurality of vanes are formed at a predetermined distance from the outer peripheral surface of the filament to attract the hot electrons by the action of an electric field and a magnetic field, The upper and lower ends are characterized in that the upper and lower pole pieces formed to face each other in the center of the working space between the vane and the filament.

Description

Pole piece structure of magnetron

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetron, and more particularly, to a pole piece structure of a magnetron that suppresses magnetic field distortion around the ends of upper and lower pole pieces in order to minimize unwanted harmonics generated during operation of the magnetron.

In general, the operation of the magnetron, as shown in Figure 1 first heats the cathode filament (1) is heated to release the hot electrons are driven while rotating toward the vanes (5) by the action of the electric and magnetic fields.

At this time, the vane (5) tip is the end of the LC parallel resonance circuit, and the (+) or (-) charge is induced so that the electrons rotating in the working space are gathered like the spokes and the rotation angle frequency of the spokes When the resonant frequency of the resonant circuit composed of the spaces between the vanes 5 is synchronized, the oscillation is stable.

Current microwave oven magnetron uses fundamental wave whose oscillation frequency is 2450MHz. In addition to the fundamental wave mentioned above, the frequency of the integer multiple, the so-called harmonic components (especially the fifth harmonic of 12.275㎓) are generated simultaneously. .

These harmonic components have a shorter wavelength, which makes it difficult to shield electromagnetic waves in a microwave oven, and they are more likely to leak to the outside. This leakage propagation can cause radio interference even when the leakage power is very weak. In addition to the regulations, the recent trend of satellite broadcasting such as TV (11.7-12.7㎓) is required to minimize the harmonic components, which are the elements of radio interference, in order to prevent interference with receiving satellite broadcasting.

Cause of the generation of harmonics is an electric field is formed from the filament 1 to the vanes 5, as shown in the accompanying Figure 2, the magnetic field comes out of the end of the upper pole piece (4) vanes (5) and filaments It is connected to the end of the lower pole piece 6 through the working space between (1) and is connected to the half arc shape according to the characteristics of the magnetic field.

In the conventional magnetron as described above, an electric field and a magnetic field are not distributed perpendicular to each other near the upper and lower pole piece ends, that is, the top head and the end head.

Accordingly, an object of the present invention is to provide a pole piece structure of a magnetron in which magnetic field distortion around the ends of upper and lower pole pieces is minimized in order to minimize unnecessary harmonics generated during operation of the conventional magnetron.

1 is a longitudinal cross-sectional view of a conventional magnetron.

Figure 2 is a sectional view of the main portion showing the action of the magnetic field and the electric field of the conventional magnetron.

Figure 3 is a longitudinal cross-sectional view of the magnetron of the present invention.

Figure 4 is a sectional view of the main portion showing the action of the magnetic field and the electric field of the magnetron of the present invention.

Explanation of symbols for the main parts of the drawings

1-filament, 2-top head,

3-end head, 5-vane,

10-top pole piece, 20-bottom pole piece.

The present invention is a magnetron for generating a high frequency by the action of an electric field and a magnetic field, the filament is formed in the center of the magnetron and the hot electrons are emitted by a heating action, and is formed at a predetermined distance from the outer peripheral surface of the filament to the electric field And a plurality of vanes drawn by the action of the magnetic field, and upper and lower pole pieces formed so as to face each other in the center of the working space between the vanes and the filaments at upper and lower sides of the vanes.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Figure 3 is a longitudinal sectional view of the magnetron of the present invention, Figure 4 is a main cross-sectional view showing the action of the magnetic field and the electric field of the magnetron of the present invention, the filament (1) for releasing hot electrons heated by the current as a cathode, and the A top hat (2) and an end hat (3) for fixing the filament (1) at the top and bottom, a vane (5) attracting hot electrons generated from the filament (1), and a magnetic field in a direction perpendicular to the hot electrons The upper pole piece 10 and the lower pole piece 20 are formed.

In the operation of the magnetron of the present invention configured as described above, when the filament 1 serving as a cathode is heated by an electric current, hot electrons are emitted. The hot electrons are caused by the action of a magnetic field generated in the upper and lower pole pieces 10 and 20. It is pulled towards the vane (2).

The vane (5) tip is the end of the resonant circuit is induced (+) or (-) charge so that the electrons that rotate in the working space is gathered like a wheel flesh, the rotation angle frequency and vanes (2) of the wheel flesh The resonant frequency of the resonant circuit composed of the spaces between them is synchronized to generate a stable high frequency.

At this time, the distribution of the magnetic field generated in the upper lower pole pieces 10, 20 of the present invention is formed so that the ends of the upper lower pole pieces 10, 20 face each other as shown in FIG. In the working space, many of the magnetic fields are perpendicular to the electric field.

In particular, the distortion of the magnetic field generated at the ends of the upper lower pole pieces 10, 20, that is, the top head 2 and the end head 3 is extremely reduced, so that the undesired harmonics are stable. Is generated.

The present invention has an effect of minimizing unnecessary harmonics generated during operation of the magnetron by providing a pole piece structure of the magnetron which suppresses the magnetic field distortion near the end of the upper and lower pole pieces.

Claims (1)

A magnetron that generates high frequency by the action of an electric field and a magnetic field, comprising: a filament (1) formed at a center of the magnetron and emitting hot electrons by a heating action; A plurality of vanes 5 formed at a predetermined distance from the outer circumferential surface of the filament 1 to attract the hot electrons by the action of an electric field and a magnetic field, The upper and lower sides of the vane 5, the pole end of the magnetron, characterized in that the upper and lower pole pieces (10, 20) formed to face each other in the working space between the vanes (5) and the filament (1) Piece structure.