JPH03102795A - Shutter for protection of launcher - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is intended to protect a microwave launcher necessary for use in heating, processing, plasma generation, etc. using high-power microwaves. This invention relates to a shutter for protecting the launcher.

(Prior Art) A device that irradiates a dielectric material with microwaves, which are a type of electromagnetic waves, to perform processing or irradiate a gas to generate plasma has a launcher portion that emits the microwaves.

FIG. 2 schematically shows an example of this, in which microwaves generated by a microwave oscillator 1 are guided to a waveguide 4 provided at an inlet port 6 of a chamber 16 that confines an irradiator 3. Reach launcher 2. The microwave emitted from the launcher 2 enters the irradiator 3 and causes a heating effect and a plasma generation effect. Between the oscillator 1 and the launcher 2, there is a matching device 5 that matches the impedance of the irradiator 3 seen from the launcher 2 and the impedance of the waveguide 4, and a power monitor 15 that measures the microwave power passing through the waveguide 4. etc. may be provided as necessary. Here, the microwave circuits such as the launcher 2, matching device 5, waveguide 4, etc. can take various shapes depending on the frequency.

In other words, in the UHF band, a horn-type antenna is suitable for the launcher 2, but in the millimeter wave band exceeding 100 GHz, electromagnetic waves can propagate while being reflected like light, and the launcher 2 is a reflective mirror with multiple mirror surfaces. It may be replaced.

Now, when trying to emit high-power microwaves from these launchers, the following problems arise.

First, when the microwave propagates within the waveguide 4 or the launcher 2, a high frequency current also flows on the surface of the conductor, but this displacement current is limited to the vicinity of the surface, and its thickness decreases with frequency. For example, for microwaves of 100 GHz, the thickness is only 0.2 μm from the copper surface.

When trying to propagate high-power microwaves, the high-frequency current also increases, so the skin needs to be covered with a highly conductive material without any breaks to minimize resistance loss.

Further, an electric field exists in the space inside the waveguide 4 or the launcher 2, and in the case of high-power microwaves, a high high-frequency voltage appears between the facing conductor surfaces.

In order to avoid electrical discharge within the waveguide 4 or launcher 2, the conductor surface must have a smooth finish with no protrusions.

On the other hand, since the launcher faces the dielectric material to be heated and processed or the generated plasma, the influence from these irradiators 3 cannot be ignored. That is, the irradiator may burst due to rapid heating, and its fragments may scatter and collide with the surface of the launcher 2. In addition, heat rays from the irradiator 3 which has reached a high temperature, a part of the generated plasma, an activated substance generated in the plasma, etc. also fly. When it becomes a high-temperature plasma, nuclear reactions occur and neutrons and other particles are also released. Since the amount of material and energy emitted from these irradiators 3 increases as the power of the microwave increases, the surface of the launcher 2 is damaged. That is, the surface of the launcher 2 is damaged by the collision of the heat rays and particle beams, resulting in surface peeling or protrusions.

As mentioned above, the condition of the conductor surface is extremely important for the propagation of high-power microwaves, so when surface peeling occurs, the high-frequency current path is blocked, causing heat generation, and there is a possibility of discharge from the tips of the protrusions.

If the high frequency current stops flowing or discharge occurs, it will be difficult to emit microwaves, which is the original function, so the launcher 2 must be protected from being affected by the irradiator 3.

As means for blocking heat rays and particle rays from the irradiator 3,
What is generally known as a shutter is known. FIG. 3 schematically shows an example of this, in which the boat 6 between the irradiation object and the object to be protected is blocked by a slide plate 17.

The slide plate 17 is connected to the drive mechanism 8 by a shaft 9, and can be opened only when necessary by a control device (not shown).

(Problems to be Solved by the Invention) However, if a shutter as shown in FIG. 3 is used to protect the high-power microwave launcher 2, a new problem will arise as described below. The slide plate 17 is usually made of metal, and at the same time blocks heat rays and particle beams from the irradiator, it also almost completely reflects microwaves. If the slide plate 17 is in the closed position while the high power microwave is being emitted, the reflected power will be reflected from the launcher 2.
The wave propagates in the opposite direction through the waveguide 4, flows back into the oscillator 1, and damages the oscillator 1. Even if it is attempted to provide a circulator or the like between the launcher 2 and the oscillator 1 in order to avoid damage to the oscillator 1 due to reflected power, the current situation is that no circulator for high power has been found. Furthermore, a control mechanism that prohibits microwave oscillation when the slide plate 17 is in the closed position can be considered, but the emission of microwaves is restricted, and if heating is performed using microwaves while monitoring the trend of high-temperature plasma. There are some tasks that are not suitable for

As described above, the surface of the launcher 2 that emits high-power microwaves may be damaged by heat rays, particle beams, etc. from the irradiator 3, which may impede microwave emission. If a conventional shutter was used to protect the launcher 2 from these heat rays and particle rays, it would damage the oscillator due to reflected power and limit microwave emission.
There is an issue that prevents effective firing.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a launcher protection shutter capable of protecting a high-power microwave launcher used for heating, processing, plasma generation, etc.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a launcher that emits microwaves, a reflection mirror disposed in the middle of an irradiation body to which microwaves are irradiated from the launcher, and this reflection mirror. The present invention is characterized in that it includes a drive mechanism that drives the microwave onto the microwave propagation path, and an electromagnetic simulating load that absorbs the microwave reflected from the reflection mirror.

That is, the shutter according to the present invention is characterized in that the reflected waves from the reflecting mirror are focused and guided to the simulated load.

(Function) In the shutter according to the present invention, the high-power microwave is reflected and guided to the simulated load, and the power is absorbed. Therefore, there is almost no reflected power that propagates backward through the waveguide and reaches the oscillator. will not damage.

Therefore, it is not limited to the operation of the oscillator, and can be opened only for the necessary time, so that the launcher can be protected for a long period of time.

Furthermore, by measuring the power absorbed by the simulated load, it can function as a power monitor that is conventionally provided in the middle of a waveguide.

(Embodiment) An embodiment of the launcher protection shutter according to the present invention will be described with reference to FIG.

In the figure, the same parts as in FIG. 2 are indicated by the same reference numerals, and the explanation of the overlapping parts will be omitted. Note that this embodiment is applied to the port 6 after the high-power microwave is emitted from the launcher 2. That is, the oscillator 1 generates high-power microwaves, and the launcher 2 emits the microwaves toward the irradiator 3. The shutter of the present invention is located at a port 6 between the launcher 2 and the irradiator 3, and is composed of a reflecting mirror 7, a drive mechanism 8, and a shaft 9.

The reflecting mirror 7 is installed in the middle of the microwave propagation path 10 emitted from the launcher 2, and the microwave reflected by the reflecting mirror 7 is directed toward the simulated load 11 installed at a different position from the launcher 2. Adjust the angle to the power microwave propagation path. The reflecting mirror 7 forms a curved surface 7a having a light-concentrating effect, and focuses the reflected waves to make them enter the simulated load 11 having a narrow entrance slit. Once the microwave has entered the simulated load 11, if the entrance slit is sufficiently small, the amount of microwave that will come out from the entrance slit is extremely small, and even if it propagates in the opposite direction, it will not damage the oscillator 1.

The reflecting mirror 7 is not only installed at an angle such that the reflected wave is directed toward the simulated load l1, but also is directed to the microwave propagation path 10 in the boat 6 via the shaft 9 and by the drive mechanism 8. It is possible to extract it from. At the pulled-out position, the high-power microwave emitted from the launcher 2 heats and processes the irradiator 3 and generates plasma.

According to the present invention, when the shutter is in a position that blocks the microwave propagation path 10, the oscillator 1 will not be damaged even if the microwave is emitted, so it is possible to take a long time to close the shutter and protect the launcher. I can do it. As a result, heating,
Damage to the launcher can be minimized without compromising processing efficiency.

Furthermore, according to the present invention, since the high-power microwave generated by the oscillator 1 is absorbed by the simulated load 11, the temperature sensors 13a and 13b and the flow meter provided in the middle of the cooling pipe 12 that cools the simulated load 11 are By reading it, the power of the microwave can be calculated. That is, it can be used as a power monitor based on calorimetry instead of a conventional power monitor in which a directional coupler or the like is provided in the middle of a waveguide to detect minute power and calculate the total power. Note that there is also the advantage that power calibration can be performed simply and accurately.

Note that the present invention is not limited to the above-mentioned excited roller. For example, the shaft 9 of the reflection mirror 7 and the drive mechanism 8 can be attached at an angle such as perpendicular to the microwave propagation path 10. Furthermore, the microwave propagation path 10 can be opened and closed by rotating the reflecting mirror 7.

[Effects of the Invention] According to the present invention, the launcher that emits high-power microwaves can be protected from heat rays or particle beams from the irradiator, and there is no risk of damage to the oscillator due to reflected power. There are many benefits to using microwaves.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an embodiment of a launcher protection shutter according to the present invention, Fig. 2 is a schematic diagram showing a conventional microwave heating and processing device, and Fig. 3 is a schematic diagram showing a conventional shutter. It is a diagram. 1... Oscillator 2... Launcher 3... Irradiator 4... Waveguide 5... Matching device 6... Port 7... Reflection mirror 8... Drive device 9... Shaft 10... Microwave propagation path 11... Simulated load 12... Cooling pipes 13a, 13b... Temperature sensor 14... Flow meter 15... Power monitor 16... Chamber 17... Slide board (8733) Agent Patent attorney Yoshiaki Inomata (and others)
1 person) Figure 1 Figure 3

Claims (1)

[Claims] a launcher that emits microwaves, a reflection mirror disposed midway between the irradiator to which the microwaves are irradiated from the launcher, a drive mechanism that drives the reflection mirror onto the microwave propagation path, and a drive mechanism that drives the reflection mirror onto the microwave propagation path; A launcher protective shutter characterized by comprising an electromagnetic simulated load that absorbs reflected microwaves.