KR100262277B1 - Blocking capacitor for use in a micro-generator of a microwave oven - Google Patents

Abstract

PURPOSE: A blocking capacitor for a micro-generator of a microwave oven is provided to simplify manufacturing process and save manufacturing costs by using a washer type ceramic dielectric having a good permittivity to promote flat polishing. CONSTITUTION: The blocking capacitor(200) employs a washer type dielectric having a good permittivity, and is positioned between a grid holder(180) and a supporter(190). It is preferable that the dielectric is ceramic having permittivity of 35-40. The supporter(190) has a discontinuous surface(192). A grid holder(180) supports a first grid(134) through an input cavity. The length(l) of the blocking capacitor is determined as follows: l=(w/2)/loot(s), where w is wavelength and s is the velocity of light. Therefore, the length of the blocking capacitor can be reduced for the compactification of the capacitor.

Description

Blocking Capacitor of Microwave Oscillator for Microwave Oven

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blocking capacitor of a microwave microwave oscillation tube, and more particularly to a blocking capacitor of a microwave microwave oscillation tube that can be easily manufactured by adopting a laminated structure of a metal plate.

In this regard, the present applicant has proposed Korean Patent Application No. 97-36327 for a microwave microwave oscillation tube having a simple structure and eliminating the risk of high voltage and achieving a light weight. As shown in FIG. 1, the ultra-high frequency oscillation tube is mounted on the upper surface of the heater 120 by placing the cathode 132 as a ring-shaped disk-shaped electron radiator in an indirect heating method and generating heat by the heater 120. When the cathode 132 is heated to about 600-1200 ° C. by the indirect heating method, hot electrons are emitted, and the released hot electrons are biased to the first grid 134 arranged at predetermined intervals on the cathode 132. As it is applied, it controls and focuses on the input cavity 130.

The electrons focused on the input cavity 130 are densely modulated by the automatic shielding function of the bias power of the first grid 134 to pass through the first grid 134, and at this time, the input / output cavities 130 and 140 insulated from each other. When the operating voltage is applied, the potential difference is generated therebetween, and electrons passing through the first grid 134 are accelerated to pass through the second grid 142, so that surface current is generated in the output cavity 140. Induced. As a result, microwaves are formed in the output cavity 140, and the formed microwaves penetrate through the center of the anode 146 and are radiated through the antenna 150 formed in the output cavity 140. For this purpose, the coupling end 152 of the antenna 150 is located in the output cavity 140.

Meanwhile, a feed rod 160 for feeding back part of the microwaves formed in the output cavity 140 to the input cavity 140 is installed at the center between the input / output cavities 130 and 140 to amplify and resonate the power of the microwave. .

As shown in FIG. 2, the input cavity 130 includes a grid holder 180 supporting the first grid 134 and a space surrounded by the support 190, and a blocking capacitor 136 made of alumina ceramic. Is arranged between the grid holder 180 and the support 190, when the cathode 132 receives the heat of the heater 120 to emit hot electrons, the first grid arranged at a predetermined interval on top of the cathode 132 Focusing phenomenon of the hot electrons is caused by the bias voltage applied to the 134, and at this time, the input cavity 130 is designed to resonate near the oscillation frequency 2450 MHz, and to insulate the voltage applied at both ends during the resonance, and ultra-high frequency Since the current i must be energized to flow along the inner surface of the support and the grid holder 180, for this purpose, the blocking capacitor 136 must form a metal plate or metalizing surface on the surface, but to create a discontinuous surface. Bar, the position of the discontinuous surface, as shown in Figure 3, when the inner surface of the flange portion 182 of the grid holder 180 is referred to as the reference plane, the portion that is λ / 4 from the reference plane, which is the conventional case One end is connected to the flange portion 182 of the grid holder 180, and the length from the reference plane to the downwardly bent portion l ₁ This is, the length back to the bending portion inwards toward the support 190 l ₂ In this case, the position P of the discontinuous surface is determined as follows.

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However, the conventional blocking capacitor of the microwave oven tube is expensive because of the characteristics of the ceramic, there is a problem that precise processing is difficult. For example, the thickness of the blocking is closely related to the assembling precision of the grid and cathode assembly to be assembled later, and in order to meet this dimension, diamond polishing on the inner surface, the outer surface, and the upper and lower portions is difficult, so that the manufacturing process is difficult. In addition, since the internal shape changes depending on the roughness of the ceramic working surface, there is a possibility that the flow of electromagnetic waves may be poor.

In addition, since the surface of the metal material or metallizing is used in the form of silk printing, it is difficult to simultaneously perform the inner surface and the outer surface, and there is a problem that metallizing is difficult because it is not a constant plane.

Accordingly, the present invention has been devised accordingly, and an object thereof is to provide a blocking capacitor for microwave microwave oscillation tubes for which a two-sided planar polishing is easy using a washer-type ceramic having a good dielectric constant, which can simplify the manufacturing process. will be.

As a means for achieving this object, the blocking capacitor of the microwave microwave oscillation tube of the present invention is surrounded by a grid holder in which the input cavity supports the first grid, a support, and a blocking capacitor arranged between the grid holder and the support. In the blocking capacitor of a microwave high frequency oscillation tube having a discontinuous surface located at a portion of λ / 4 when the inner surface of the flange portion of the grid holder is referred to as a reference surface, the blocking capacitor has a good dielectric constant. The washer-type dielectric of the material is arranged between the grid holder and the support, characterized in that a discontinuous surface is located on the support.

Since the blocking capacitor of the present invention uses a washer-type dielectric, the length of the blocking capacitor can be reduced when the inner surface of the flange portion of the grid holder is used as a reference surface, thereby miniaturizing and compacting, and planar polishing for matching the degree of assembly of both surfaces. Since the manufacturing process is simplified, the manufacturing cost is reduced.

1 is a cross-sectional view showing the structure of a conventional microwave oven for microwave oven,

FIG. 2 is an enlarged detailed view of a mounting state of the blocking capacitor of FIG. 1;

3 is a waveform diagram showing waveforms of a current and an electric field between a reference plane and a wavelength;

4 is an enlarged detailed view of a mounting state of a blocking capacitor according to a preferred embodiment of the present invention.

<Description of the code | symbol about the principal part of drawing>

120: heater 130: input cavity

132: cathode 134: first grid

140: output cavity 142: second grid

146: anode 150: antenna

160: feedback rod 180: grid holder

182: flange 190: support

192: discontinuous surface 200: blocking capacitor

Hereinafter, with reference to the accompanying drawings will be described in detail the blocking capacitor of the microwave microwave tube according to a preferred embodiment of the present invention. For convenience of explanation, the same reference numerals are given to the same configuration as in the prior art.

Figure 4 shows a preferred embodiment of the blocking capacitor of the present invention, as shown, the blocking capacitor 200 of the present invention employs a washer-type dielectric of a material having a good dielectric constant, the grid holder 180 and Arranged between the supports 190. At this time, the dielectric material is preferably a material having a good dielectric constant, more preferably a ceramic material having a dielectric constant of 35-40.

In the blocking capacitor of the present invention, the discontinuous surface 192 is positioned on the support 190.

When the inner surface of the flange portion 182 of the grid holder 180 is used as the reference surface, the length of the blocking capacitor ( l ) Becomes

At this time, the speed of light 3 × 10 ¹⁰ Since the lambda is calculated to be approximately 12.24 cm when the oscillation frequency is 2450 MHz, the length of the blocking capacitor can be approximately 1 cm, which enables miniaturization and compactness.

In addition, since the blocking capacitor of the present invention is a washer-type ceramic dielectric, it is easy to manufacture, and planar polishing for easy assembly of both surfaces is facilitated.

As described above, the blocking capacitor of the microwave microwave oscillation tube of the present invention uses a washer-type ceramic dielectric having a good dielectric constant, thereby simplifying the manufacturing process and reducing the manufacturing cost.

Claims (2)

The input cavity is composed of a grid holder supporting the first grid, a support, and a space surrounded by blocking capacitors arranged between the grid holder and the support, and when the inner surface of the flange portion of the grid holder is referred to as a reference plane, In the blocking capacitor of the microwave microwave oscillation tube located in the part of (lambda) / 4, The blocking capacitor is a blocking capacitor of the microwave oscillating tube for microwave oven, characterized in that the washer-like dielectric having a good dielectric constant arranged between the grid holder and the support, the discontinuous surface is located on the support. 2. The blocking capacitor of claim 1, wherein the dielectric is a ceramic having a dielectric constant of 35-40.

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