JP7389444B2 - Microwave heating device, heating method and chemical reaction method - Google Patents

Description

The present invention relates to a microwave heating device, a heating method, and a chemical reaction method.

Microwaves have been widely used for household purposes such as microwave ovens, and have since been studied for practical development and use as industrial heating systems. Microwave irradiation has the advantage that it can be heated in a short time because the object to be heated directly generates heat, and that temperature unevenness caused by heat conduction can be reduced. Other advantages include being able to heat without contact and selectively heating only those materials that have good microwave absorption.
In industrial fields such as film formation, semiconductor device manufacturing, printing, electronic wiring, and surface treatment, continuous heat treatment of sheet materials or thin films coated on the surface of sheet materials is an effective way to automate heat treatment and save labor. This leads to improvements in production costs and quality. Therefore, various methods have been proposed for continuous microwave heat treatment.

In heat treatment using microwave irradiation, microwaves, which are electromagnetic waves, tend to cause uneven heating because the energy intensity changes with the wavelength cycle. For this reason, countermeasures such as uniformly heating the object by temporally moving the position of the object to be heated are often taken. As a technique for dealing with this problem, for example, Patent Document 1 describes a microwave heating device using a cavity resonator. This technique describes that a TM ₁₁₀ mode standing wave is generated in a rectangular parallelepiped cavity resonator to uniformly heat a sheet containing a conductive or magnetic thin film with high efficiency. Furthermore, Patent Document 2 discloses that a microwave heating device using a rectangular waveguide (a rectangular cavity resonator) places an object to be heated at a position where the magnetic field of a standing wave is maximum, and It is described that heating can be performed efficiently by moving the heating element to that position.
It is said that by using a cavity resonator in this manner, a standing wave is formed inside and the object to be heated can be heated uniformly and with high efficiency.

Japanese Patent Application Publication No. 2006-221958 Japanese Patent Application Publication No. 2013-101808

When forming a standing wave using a cavity resonator, the state of the standing wave inside the cavity is monitored in order to continuously generate a standing wave, and the frequency of the microwave supplied to the cavity is adjusted as necessary. The resonant frequency can be adjusted by adjusting the resonant frequency or inserting a dielectric or metal piece into the cavity. In such a case, when a dielectric material or a metal piece is inserted into the cavity, a shift may occur in the magnetic field strength distribution of the standing wave formed within the cavity resonator depending on the amount of insertion. As a result, when heating an object to be heated, if the object to be heated is always supplied to a fixed position within the cavity resonator, there is a gap between the supply position of the object to be heated and the maximum position of the magnetic field strength. A deviation will occur. In order to deal with this, it is conceivable to change the supply position of the object to be heated so as to follow the changed maximum position of the magnetic field strength, but this would require a large-scale apparatus and is not practical.

The present invention uses a standing wave formed in a cavity resonator to generate magnetic materials, materials with magnetic loss, or conductive materials, and conductive materials including magnetic materials, materials with magnetic loss, and semiconductors. To provide a microwave heating device capable of efficiently and highly reproducibly heating an object to be heated made of a composite material including: The task is to

The present inventors have made extensive studies in view of the above problems. As a result, they found that by using a cylindrical cavity resonator, it is possible to form a standing wave in which the maximum part of the magnetic field is always aligned with the central axis of the cavity resonator. Then, by supplying a heated target made of a material with magnetic loss or a composite material containing a material with magnetic loss so as to pass through the central axis of the cavity resonator, the heated state of the supplied heated target is controlled. We found that it is possible to keep the value constant.
The present invention was completed after further studies based on these findings.

That is, the above-mentioned problems of the present invention are solved by the following means.
[1]
A cavity resonator that is a polygonal cylinder-shaped microwave irradiation space with two parallel faces centered on the cylinder center axis, excluding cylinders or cylinders whose cross section in the direction perpendicular to the cylinder center axis is rectangular;
A heated object made of a magnetic material, a material with magnetic loss, or a conductive material, or a magnetic material, a material with magnetic loss, in a space where the energy distribution of the magnetic field (magnetic field) in the cavity resonator is uniform. or a supply unit for supplying a heated object made of a composite material containing a conductive material through a magnetic field irradiation space where the magnetic field strength of the cavity resonator is maximum and uniform;
A microwave heating device that heats the object to be heated supplied by the supply unit in the magnetic field irradiation space.
[2]
The microwave heating device according to [1], wherein the supply section causes the object to be heated to pass through a space where the electric field (electric field) intensity is minimal when the object to be heated passes through the microwave irradiation space.
[3]
The standing wave formed inside the microwave irradiation space is a TM ₁₁₀ mode,
The microwave heating device according to [1] or [2], wherein the magnetic field irradiation space is a space along the central axis of the cylinder of the cavity resonator.
[4]
The means for forming the TM ₁₁₀ mode standing wave is a microwave generator that always maintains a uniform distribution state of the magnetic field along the cylinder center axis when the object to be heated is inserted into the microwave irradiation space. The microwave heating device according to [3], which has a mechanism for controlling the frequency of.
[5]
The mechanism for controlling the frequency of the microwave detects a resonant frequency that matches a standing wave of TM ₁₁₀ mode that varies depending on the insertion state of the object to be heated, and irradiates the microwave that matches the resonant frequency. The microwave heating device according to [4].
[6]
The means for detecting a resonant frequency that matches the standing wave of the TM ₁₁₀ mode has a mechanism that measures reflected waves from the microwave irradiation space, and determines the frequency at which the reflected waves are minimum based on the measurement signal. The microwave heating device according to [5], further comprising a mechanism for controlling the frequency of the microwave that detects a resonance frequency.
[7]
The means for detecting the resonant frequency matching the standing wave of the TM ₁₁₀ mode has a mechanism for measuring the energy state in the microwave irradiation space, and detects the energy state in the microwave irradiation space based on the measurement signal. The microwave heating device according to [5], further comprising a mechanism for controlling the frequency of the microwave for detecting the resonance frequency from the frequency at which the density is maximum.
[8]
Any one of [1] to [7], wherein an induced current is generated in the object to be heated by applying a magnetic field that becomes maximum at the central axis of the cylinder of the cavity resonator, and the object to be heated is heated. Microwave heating device as described.
[9]
The microwave heating device according to any one of [1] to [8], wherein the microwave heating device is a chemical reaction device that heats the object to be heated using microwaves to cause a chemical reaction.
[10]
A heating method using the microwave heating device according to any one of [1] to [9].
[11]
A chemical reaction method using the microwave heating device according to any one of [1] to [9], the method comprising causing a chemical reaction by heating the object to be heated.

The microwave heating device of the present invention allows the object to be heated to pass through a position where the magnetic field strength within the cavity resonator is maximum and uniform when a standing wave is formed within the cavity resonator. It is possible to heat efficiently, uniformly and with high reproducibility.

1 is a schematic cross-sectional view schematically showing an example of a preferred embodiment of a microwave heating device of the present invention. 3A and 3B are electric and magnetic field distribution diagrams generated in a cylindrical cavity resonator, in which (A) is an electric field distribution diagram and (B) is a magnetic field distribution diagram. Temperature change of the sheet material of the antistatic aluminum vapor-deposited bag used in Example 3 while being heated while moving in the magnetic field irradiation (reaction) space, incident waves, reflected waves, and resonance of the microwave heating device 1 FIG. 3 is a diagram showing changes in frequency. This is a temperature distribution diagram in the width direction of the sheet material measured using a thermal image measurement device when the sheet material of the antistatic aluminum vapor-deposited bag used in Example 3 was heated while being moved in the magnetic field irradiation (reaction) space. be. In the figure, the area shown in curly brackets represents the width of the sheet material. It is a figure which shows the result of heating conductive glass by changing the microwave output, and the temperature measurement result of the center part of a sheet|seat using a radiation thermometer, respectively. FIG. 4 is a diagram showing the results of heating the conductive silicone rubber by changing the microwave output and measuring the temperature at the center of the sheet using a radiation thermometer. Temperature change of the sheet material when the applied conductive paste used in Example 7 was placed in the center of the magnetic field irradiation (reaction) space and heated, and the incident wave and reflected wave of the microwave heating device 1, FIG. 3 is a diagram showing changes in resonance frequency. Temperature distribution diagram in the width direction of the sheet material of the conductive paste used in Example 7 measured using a thermal image measurement device when the sheet material was placed in the center of the magnetic field irradiation (reaction) space and heated. It is. In the figure, the area shown in curly brackets represents the width of the sheet material. These are photographs substituted for drawings showing the appearance of the conductive paste sheet material used in Example 7, (A) is the observation result before magnetic field heating, and (B) is the observation result after magnetic field heating. . The temperature change of the sheet material when the sheet material of the conductive paste used in Comparative Example 8 was installed in the center of the cavity resonator and dielectric heating was performed by forming a TM ₀₁₀ mode standing wave, and FIG. 2 is a diagram showing changes in incident waves, reflected waves, and resonant frequency of a microwave heating device. When a silicon substrate, which is one of the semiconductor materials used in Example 9, is placed in the center of the magnetic field irradiation (reaction) space and heated, the time change in the substrate surface temperature measured using a radiation thermometer is shown. FIG.

Preferred embodiments of the microwave heating device of the present invention will be described below with reference to the drawings.

[Microwave heating device]
A preferred embodiment of the microwave heating device of the present invention will be described with reference to FIG. 1, taking as an example a microwave heating device having a cylindrical cavity resonator.
As shown in FIG. 1, the microwave heating device 1 includes a cavity resonator (hereinafter also referred to as a (cylindrical) cavity resonator) 11 having a cylindrical microwave irradiation space. Even if the cavity resonator 11 is cylindrical, it has two faces facing each other around the cylinder center axis, except for cylinders whose cross section perpendicular to the cylinder center axis is rectangular (hereinafter referred to as rectangular cylinder type). Even with a parallel polygonal cylinder shape, a standing wave with maximum magnetic field strength and uniformity can be formed at the central axis.
The cavity resonator 11 has a cylindrical wall 11SA provided on the body wall 11SA of the cavity resonator 11, which faces across the cylinder center axis (hereinafter also referred to as the cylinder center axis or center axis) C of the cavity resonator. It has a supply port 12 and a discharge port 13 provided in a body wall 11SB facing the body wall 11SA. In addition, an object to be heated made of a material with magnetic loss, a conductive material, or a composite material containing a material with magnetic loss or conductivity is placed in the magnetic field irradiation space where the magnetic field strength in the cavity resonator 11 is maximum and uniform. A supply unit 31 is provided. The term "maximum" includes a portion where the magnetic field strength around the maximum point is stronger than in other regions. For example, the area is 3/4 or more of the maximum value. Moreover, "a material with magnetic loss or a composite material containing a material with magnetic loss" can also be said to be "a material that has magnetism or conductivity, or a composite material that includes a material that has magnetism or conductivity." Furthermore, it has an antenna 25 for supplying microwaves that form standing waves within the cavity resonator 11 .
Examples of materials with magnetic loss include iron, nickel, and cobalt, and alloys containing iron group elements and rare earth elements include Fe-Ni, Fe-Co, Fe-Ni-Co-Al, and Fe-Ni-Cr. , MnAl, and compounds include SmCo ₅ and SmCo ₅ . Further, there are also Fe ₃ O ₄ and the like as oxides. Materials that cause magnetic loss are not only magnetic materials, but also conductive materials such as aluminum, copper, and tin that cause magnetic loss due to eddy currents. Conductive materials include semiconductor materials. Semiconductor materials include silicon and germanium, and compound semiconductors include ZnSe, CdS, ZnO, GaAs, InP, GaN, SiC, and SiGe. It also includes materials in which impurities are implanted into these semiconductor materials to control conductivity. Carriers responsible for conductivity include not only electrons but also holes formed within the semiconductor, which can cause heating effects by microwaves.

For example, in the case of a cylindrical cavity resonator 11 that generates a _TM110 mode standing wave, in the magnetic field irradiation space, the magnetic field strength is maximum at the central axis C, and the magnetic field strength is uniform along the central axis C. It is a space where It is preferable that the sheet 6 of the object to be heated is arranged so as to pass through the magnetic field irradiation space, that is, to pass through the central axis C. Further, it is preferable that the sheet 6 is arranged so as to pass along the symmetry plane of the cavity resonator. Therefore, it is preferable that the supply port 12 and the discharge port 13 of the sheet 6 are arranged in the body walls 11SA and 11SB of the cylindrical cavity resonator 11 at opposing positions with the central axis C interposed therebetween. In other words, it is preferable that the supply port 12, the central axis C, and the discharge port 13 are arranged at positions including the same plane. The above-mentioned "sheet" is used to include anything from thin materials such as paper or film to substrates having a certain degree of thickness such as semiconductor substrates and wiring boards.
A microwave generator 21 is disposed in the cavity resonator 11, and microwaves are supplied to the cavity resonator 11. Generally, the S band of 2 to 4 GHz is used as the microwave frequency. Alternatively, 900 to 930 MHz or 5.725 to 5.875 GHz may be used. However, other frequencies can also be used.

In the microwave heating device 1 described above, microwaves generated by the microwave generator 21 are supplied to the cavity resonator 11 from the microwave supply port 14, and the microwave is supplied to the cavity resonator 11 from the microwave supply port 14. A standing wave is formed at the central axis C of 11. As the microwave supply port 14, for example, a coaxial waveguide converter type microwave supply port can be used. The sheet 6, which is the object to be heated, is heated at the portion where the magnetic field strength of the standing wave is maximum (the central axis C of the cylindrical resonator 11).

In the microwave heating device 1, the microwaves supplied from the microwave generator 21 are supplied with the frequency adjusted. By adjusting the frequency, the magnetic field strength distribution of the standing wave formed within the cavity resonator 11 can be controlled to a desired distribution state, and the strength of the standing wave can be adjusted by the output of the microwave. In other words, it becomes possible to control the heating state of the object to be heated.
Note that the frequency of the microwave supplied from the microwave supply port 14 is such that a specific single mode standing wave can be formed within the cavity resonator 11.
The configuration of the microwave heating device 1 of the present invention will be explained in order.

<Cavity resonator>
A cylindrical cavity resonator (cavity) 11 used in a microwave heating device has one microwave supply port 14, and a single mode standing wave is formed when microwaves are supplied. There are no particular restrictions. The cavity resonator used in the present invention is not limited to the cylindrical shape shown in the drawings. In other words, even if it is not a cylindrical cavity resonator, it may be a polygonal cylindrical cavity with two parallel faces centered on the central axis, excluding a cylindrical type with a rectangular cross section perpendicular to the central axis. good. For example, the cross section perpendicular to the central axis is opposite to the central axis of a regular hexagon, regular octagon, dodecagon, regular hexagon, etc., or a regular even polygonal cylinder shape. It may be a polygonal cylindrical shape crushed between two sides. In the case of the polygonal cylindrical cavity resonator described above, the corners inside the cavity resonator may be rounded. Further, the microwave irradiation space may be a cavity resonator having a columnar shape, an ellipsoid, or the like with increased roundness, in addition to the above-mentioned cylindrical shape.
Even with such a polygonal shape, it is possible to achieve the same effect as a cylindrical shape (that is, it is possible to form a standing wave with maximum magnetic field strength and uniformity at the central axis).
The size of the cavity resonator 11 can also be appropriately designed depending on the purpose. The cavity resonator 11 preferably has a low electrical resistivity and is usually made of metal, such as aluminum, copper, iron, magnesium, brass, stainless steel, or an alloy thereof. Alternatively, the surface of resin, ceramic, or metal may be coated with a substance having low electrical resistivity by plating, vapor deposition, or the like. Materials containing silver, copper, gold, tin, and rhodium can be used for the coating.

<Supply section>
The supply section 31 includes a supply side conveyance section 31A and a delivery side conveyance section 31B.
The supply side conveyance section 31A is composed of a pair of nip rolls 32A and 32B, and one of the nip rolls is provided with a rotational drive device (not shown) for driving the nip rolls. The sheet 6 sandwiched between the nip rolls 32A and 32B is conveyed into the cavity resonator 11 by the rotation of the nip rolls 32A and 32B. The sending-out side conveying section 31B is composed of a pair of nip rolls 33A and 33B, and one of the nip rolls is provided with a rotational drive device (not shown) for driving the nip rolls. The rotation of the nip rolls 33A, 33B transports the sheet 6 sandwiched between the nip rolls 33A, 33B to the outside of the cavity resonator 11. It is preferable that the supply side conveyance section 31A and the delivery side conveyance section 31B always convey the sheet 6 at a constant speed. Further, it is preferable that the circumferential speeds of the nip rolls 32A, 32B, 33A, and 33B are the same.
As another supply method, a plate with low magnetic loss may be used as a support (not shown) and suspended from the supply port 12 to the discharge port 13, and the object to be heated may be placed on top of the plate. In this case, as means for moving the object to be heated, a support stand may be moved, or the object to be heated may be pushed in or pulled out.
Alternatively, the supply section 31, supply port 12, and discharge port 13 may not be provided. In this case, the object to be heated is placed in advance at a position where the magnetic field inside the cavity resonator is at its maximum, and after processing for an appropriate period of time, the microwave is stopped, a part of the cavity resonator is opened, and the The object to be heated can be taken out.
Alternatively, the cavity resonator itself can be moved without using a special transport mechanism as the supply section 31. In this case, the object to be heated 6 is fixed, and the cavity resonator itself is moved along the object to be heated so that the position where the magnetic field inside the cavity resonator is at its maximum does not deviate from the object to be heated. It is suitable to move it in parallel.
Alternatively, the supply port 12 and the discharge port 13 may be arranged along the direction of gravity. In the case of a flexible object to be heated, since it hangs down according to gravity, the object to be heated 6 may be fed out according to gravity with the supply port 12 facing upward. Alternatively, it may be pulled out against gravity with the outlet 13 facing upward.

<Microwave supply>
For supplying microwaves, it is preferable to include a microwave generator 21, a microwave amplifier 22, an isolator 23, an impedance matching device 24, and an antenna 25.

A microwave supply port 14 is provided on or near a wall surface (inner surface of the cylinder) parallel to the central axis C of the cavity resonator 11 . In one embodiment, the microwave supply port 14 has an antenna 25 capable of applying high frequency waves. FIG. 1 shows a microwave supply port 14 using a coaxial waveguide converter. In this case, the antenna 25 is an electric field excitation type monopole antenna. In order to effectively form a standing wave at this time, an iris (not shown) may be used as an appropriate opening between the microwave supply port 14 and the cavity resonator 11. Further, the antenna may be installed directly on the cavity resonator 11 without using the microwave supply port 14. In this case, a loop antenna (not shown) serving as a time-excited antenna may be installed near the side wall of the cavity resonator. Alternatively, it is also possible to install a monopole antenna for electric field excitation on the upper or lower surface of the cavity resonator.
Antenna 25 receives microwaves from microwave generator 21 . Specifically, the microwave amplifier 22, isolator 23, matching box 24, and antenna 25 are connected to the microwave generator 21 in this order via each cable 26 (26A, 26B, 26C, 26D). There is.
For each cable 26, a coaxial cable is used, for example. In this configuration, microwaves emitted from the microwave generator 21 are supplied into the cavity resonator 11 from the microwave supply port 14 by the antenna 25 via each cable 26 .

[Microwave generator]
As the microwave generator 21 used in the microwave heating device 1 of the present invention, for example, a microwave generator such as a magnetron or a microwave generator using a semiconductor solid-state element can be used. From the viewpoint of being able to finely adjust the frequency of the microwave, it is preferable to use a VCO (Voltage-Controlled Oscillator), a VCXO (Voltage-controlled Xtal oscillator), or a PLL (Phase-locked loop) oscillator.

[Microwave amplifier]
The microwave heating device 1 in FIG. 1 includes a microwave amplifier 22. The microwave heating device 1 shown in FIG. The microwave amplifier 22 has a function of amplifying the output of the microwave generated by the microwave generator 21. Although there is no particular restriction on its configuration, it is preferable to use a semiconductor solid-state element configured with a high-frequency transistor circuit, for example. If a microwave generator with a large oscillation output, such as a magnetron, is used, the microwave amplification circuit may not be used.

[Isolator]
The microwave heating device 1 in FIG. 1 includes an isolator 23. The isolator 23 is for protecting the microwave generator 21 by suppressing the influence of reflected waves generated within the cavity resonator 11, and is designed to supply microwaves in one direction (the direction of the antenna 25). It is something to do. If there is no risk that the microwave amplifier 22 or the microwave generator 21 will be damaged by reflected waves, it is not necessary to install an isolator. In this case, there are advantages that the device can be made smaller and the cost can be reduced.

[Matching box]
The microwave heating device 1 in FIG. 1 includes a matching box 24. The matching device 24 is for matching (matching) the impedance of the microwave generator 21 to the isolator 23 and the impedance of the antenna 25. If there is no risk that the microwave amplifier 22 or the microwave generator 21 will be damaged even if a reflected wave is generated due to mismatching, it is not necessary to install a matching box. Alternatively, by adjusting the antenna structure, the circuit constants of the microwave amplifier 22, and the cable 26 in advance so that mismatch does not occur, it is also possible to omit the installation of a matching box. In this case, there are advantages that the device can be made smaller and the cost can be reduced.

[antenna]
For example, a monopole antenna, a loop antenna, or a patch antenna can be used as the antenna 25. In the case of a monopole antenna, the end of the antenna is exposed in space through an insulator from the housing so that the housing of the cavity resonator 11 or the housing of the microwave supply port functions as a ground plane (Fig. (not shown). In the case of a loop antenna, the end of the loop antenna is connected to a ground potential such as a cavity resonator wall surface (not shown). By applying a microwave (high frequency) to this antenna 25, a magnetic field is excited within the loop, and a standing wave can be formed within the cavity resonator.
For example, when a single mode standing wave of TM ₁₁₀ is formed in the above-mentioned cylindrical cavity resonator, the magnetic field strength is maximum at the central axis C, and the magnetic field strength is uniform in the central axis C direction. Therefore, in the sheet 6, it becomes possible to uniformly and highly efficiently microwave the object to be heated, which is present on the upper surface of the sheet 6 or is the sheet itself.

<Control system>
The microwave heating device 1 is provided with a thermal image measuring device (thermo viewer) 41 or a radiation thermometer (not shown) that measures the temperature of the sheet 6 of the object to be heated. The cavity resonator 11 is provided with a window 15 for measuring the temperature distribution of the sheet 6 using a thermal image measuring device 41 or a radiation thermometer (not shown). A measurement image of the temperature distribution of the sheet 6 measured by the thermal image measuring device 41 or temperature information measured by the radiation thermometer is transmitted to the control unit 43 via the cable 42. Further, an electromagnetic wave sensor 44 is arranged on the body wall 11S of the cavity resonator 11. A signal corresponding to the electromagnetic field energy within the cavity resonator 11 detected by the electromagnetic wave sensor 44 is transmitted to the control unit 43 via the cable 45. The control unit 43 can detect the formation status (resonance status) of standing waves generated within the cavity resonator 11 based on the signal from the electromagnetic wave sensor 44 . When a standing wave is formed, that is, when it resonates, the output of the electromagnetic wave sensor 44 increases. By adjusting the oscillation frequency of the microwave generator so that the output of the electromagnetic wave sensor 44 becomes maximum, the microwave frequency can be controlled to match the resonance frequency of the cavity resonator 11. Since the resonant frequency varies depending on the conditions of the object to be heated (inserted state, temperature, etc.), this control needs to be performed at appropriate intervals. If the change is rapid, if the supply rate of the object to be heated is fast, or if the supply rate fluctuates, it is desirable to conduct the heating at intervals of 1 millisecond to 1 second. If the change is small, such as when the object to be heated is fixed or the supply rate does not fluctuate, the heating may be performed at intervals of 10 seconds to 1 minute. Alternatively, if the resonance frequency is determined once before heating, there may be no need for constant control thereafter.

Based on the detected frequency, the control unit 43 feeds back the frequency of the microwave that causes a standing wave of a constant frequency within the cavity resonator 11 to the microwave generator 21 via the cable 46. Based on this feedback, the control unit 43 precisely controls the frequency of the microwave supplied from the microwave generator 21. In this way, standing waves can be stably generated within the cavity resonator 11. Therefore, the sheet 6 of the object to be heated can be efficiently and uniformly heated with high reproducibility by the standing waves. Further, the control unit 43 can adjust the output of microwaves to the antenna 25 by instructing the microwave amplifier 22 to output microwaves. Alternatively, the attenuation factor of an attenuator (not shown) installed between the microwave generator 21 and the microwave amplifier 22 may be adjusted according to instructions from the control unit 43 without changing the amplification factor of the microwave amplifier 22. can. The microwave output may be feedback-controlled based on the indicated value of the thermal image measuring device 41 or the radiation thermometer so that the heated object reaches the target temperature. If a device capable of producing a large output, such as a magnetron, is used as the microwave oscillator 21, the controller 43 may instruct the microwave generator 21 to adjust the microwave output.

As a control method that does not use the electromagnetic wave sensor 44, the magnitude of the reflected wave of the cavity resonator 11 may be measured and the value may be used. The amount of isolation obtained from the isolator 23 can be used to measure the reflected waves. Alternatively, a reflected signal obtained from a directional coupler (not shown) installed between the matching device 24 (if not installed, the cable 26D connected to the microwave supply port) and the isolator 23 can be used. By adjusting the frequency of the microwave generator so that the reflected wave signal becomes minimum, microwave energy can be efficiently supplied to the cavity resonator 11. At this time, it is highly likely that the resonance frequency of the cavity resonator 11 and the frequency of the microwave generator match. However, in this method, there is a possibility that the microwave is consumed by the cable 26, the antenna 25, the waveguide 14, etc., and the microwave may not necessarily match the resonant frequency.

<Heating the object to be heated>
In the microwave heating device 1 of the present invention, the object to be heated is a material with magnetic loss or a composite material containing a material with magnetic loss, in other words, a material with magnetism or conductivity or a material with magnetism or conductivity. It is a composite material containing materials that have Such objects to be heated are arranged in correspondence with the magnetic field strength inside the cavity resonator 11. In particular, more efficient heating can be achieved by arranging them along the portion where the magnetic field strength of the standing wave formed within the cavity resonator 11 is maximum. Specifically, the sheet 6 is supplied from the supply port 12 and discharged from the discharge port 13 so as to pass through the central axis C of the cavity resonator 11 .
It is preferable that the object to be heated does not pass through a portion where the electric field is maximum. For example, if a conductive material such as a metal is placed in an electric field, spark discharge may occur, which may damage the object to be heated. As shown in FIG. 2A, in the electric field distribution in the TM ₁₁₀ mode, the electric field strength is minimal on the horizontal plane passing through the central axis C (when the microwave supply port 14 is placed vertically below). By arranging, supplying and discharging the object to be heated along this plane, damage to the object to be heated due to the electric field can be suppressed. Note that the region where the electric field strength is minimum is approximately 1/4 of the maximum electric field strength within the cavity resonator.

In the microwave heating device 1 shown in FIG. 1, there is no particular restriction on the object to be heated, as long as it is a material with magnetic loss or conductivity, or a composite material containing a material with magnetic loss or conductivity; , solids, powders and mixtures thereof can also be heated.
When the object to be heated is a liquid, solid, or powder, the temperature of the object to be heated can be continuously controlled by arranging and conveying them on a sheet. The microwave heating device 1 of the present invention can selectively heat an object to be heated on a sheet. For example, solder on a substrate can be selectively heated. Further, since the progress of many chemical reactions can be controlled by temperature, it is preferable that the microwave heating device 1 of the present invention is used for controlling chemical reactions.
The object to be heated may itself be able to maintain its sheet shape. For example, if the object to be heated is a fibrous solid, it can be transported without support such as a sheet.
Further, when the object to be heated is a catalyst, the microwave heating device 1 of the present invention can be used to cause a chemical reaction due to the action of the catalyst, as will be described later. It is also preferable that the catalyst be supported on a sheet.
The above chemical reactions include rearrangement reaction, substitution reaction, addition reaction, cyclization reaction, reduction reaction, oxidation reaction, selective catalytic reduction reaction, selective oxidation reaction, racemization reaction, cleavage reaction, catalytic cracking reaction (cracking), etc. Examples include, but are not limited to, various chemical reactions.

In the chemical reaction method of the present invention, conditions such as reaction time, reaction temperature, reaction substrate, and reaction medium may be appropriately set depending on the desired chemical reaction. For example, Chemistry Handbook (edited by Shuichi Suzuki and Mitsuaki Mukaiyama, Asakura Shoten, 2005), Microwave Chemical Process Technology II (edited by Kazuhiko Takeuchi and Yuji Wada, CMC Publishing, 2013), Japanese Patent Application Publication No. 2010-215677, etc. With reference to this, chemical reaction conditions can be set appropriately.

In the form shown in FIG. 1, the frequency of the standing wave is not particularly limited as long as a standing wave can be formed within the cavity resonator 11. When microwaves are supplied from the microwave supply port 14, the frequency can be set at such a frequency that the above-mentioned TM ₁₁₀ mode standing wave is formed within the cavity resonator 11. In addition to the TM ₁₁₀ mode standing wave, examples include TM ₂₁₀ , TM ₃₁₀ , and TM ₄₁₀ modes. The standing wave of TM ₁₁₀ is most preferable because it can efficiently form the maximum part of the magnetic field strength along the central axis C of the cavity resonator 11. In addition, if the object to be heated is a conductive material, it is undesirable for the object to be heated to pass through areas where the electric field is concentrated, so the electric field strength will be minimal on the surface that passes through the maximum magnetic field strength. Particularly preferred is the TM ₁₁₀ mode in which surfaces can be formed. In this way, by passing the object to be heated through the surface where the electric field intensity is minimal, the object to be heated will not be destroyed by the electric field.
When a cube or a rectangular parallelepiped with a square cross section in the direction perpendicular to the central axis is used as the cavity resonator, TE _10n (n is an integer of 2 or more) similarly forms an electromagnetic wave irradiation space having a maximum part of the magnetic field strength. I can do it.

The means for forming a standing wave in the TM ₁₁₀ mode is to maintain a uniform distribution of the magnetic field along the central axis C of the cylinder while the object to be heated is inserted into the cavity resonator 11 (microwave irradiation space). It is preferable to have a mechanism for controlling the microwave frequency in order to maintain the microwave frequency. Alternatively, it is preferable to have a mechanism for controlling the shape of the microwave irradiation space.

Specifically, the mechanism that controls the frequency of the microwave detects a resonant frequency that matches the standing wave of the _TM110 mode that changes depending on the insertion state of the object to be heated, and It emits waves.
In the resonance state of the TM ₁₁₀ mode, energy is efficiently supplied into the cavity resonator 11. At this time, since the output of the electromagnetic wave sensor 44 installed on the side wall of the cavity resonator outputs a signal proportional to the energy intensity within the cavity resonator 11, the microwave is generated so that the output amount of this signal becomes maximum. The oscillation frequency of the device 21 may be adjusted. As a method of adjustment, by sweeping the oscillation frequency of the microwave generator 21 in a certain range (100 MHz as an example), it is possible to obtain a spectrum in which the output of the electromagnetic wave sensor 44 has a peak at a point that coincides with the resonance frequency. By comparing this spectrum with the theoretical resonance frequency derived from the shape of the cavity resonator, etc., the resonance frequency of the TM ₁₁₀ mode can be identified. Once identified, if the oscillation frequency of the microwave generator 21 is periodically swept in a narrow range (5 MHz as an example) near the resonance frequency, it can be Changes in the TM ₁₁₀ mode resonant frequency can be tracked. Therefore, optimal microwave irradiation conditions can be maintained at all times. It is desirable that the interval and sweep width for tracking the resonance frequency be appropriately monitored depending on the speed and amount of change in the object to be heated (supply speed, amount of temperature change, uniformity).

Another method for measuring the energy intensity within the cavity resonator is to use the intensity of the reflected wave from the microwave irradiation antenna 25. In this case, it is utilized that when the energy intensity within the cavity resonator is high, the reflected wave becomes small. Specifically, the oscillation frequency of the microwave generator is adjusted so that the reflected wave intensity becomes minimum.
However, in the method using reflected waves, the signal strength changes due to the superposition of multiple factors such as the antenna 25, matching device 24, microwave irradiation port 14, and cable 26 in addition to the cavity resonator. If precise control is required, it is preferable to use an electromagnetic wave sensor 44 directly attached to the cavity resonator.

Another method for matching the resonant frequency of the cavity resonator 11 with the oscillation frequency of the microwave generator is to adjust the resonant frequency by changing the shape of the microwave irradiation space. Specifically, the resonant frequency can be adjusted by inserting a dielectric or a metal piece into the cavity resonator. For example, if a dielectric material (not shown) with low microwave absorption such as ceramic or Teflon (registered trademark) is inserted into the cavity resonator 11, the resonant frequency will change to a lower value depending on the dielectric constant and the amount of insertion. do. When a piece of metal such as aluminum or copper is inserted in place of the dielectric, the resonant frequency changes toward higher levels. By using a mechanism that automatically adjusts the insertion amount, even in a case where the oscillation frequency of the microwave generator cannot be changed like a magnetron, the resonance frequency and the oscillation frequency of the microwave generator can be matched.
However, when a dielectric or metal is inserted into the cavity resonator 11, the position where the magnetic field becomes maximum also moves depending on the amount and position of insertion. For this reason, it is desirable to appropriately manage the position at which the object to be heated is supplied.

As described above, a mechanism is provided to control the amount of dielectric or metal inserted into the microwave irradiation space in the cavity resonator 11, or to adjust the resonant frequency that matches the standing wave of the _TM110 mode. It is preferable that the frequency of the microwave irradiated from the microwave generator and the resonant frequency be matched by providing the resonant frequency.

It is desirable that the cavity resonator 11 is designed so that its resonant frequency falls within the ISM band. Since the resonant frequency fluctuates due to changes in temperature and composition of the object to be heated, it is desirable that the resonant frequency falls within the ISM band after considering the range of the fluctuation. "ISM" is an abbreviation for Industry Science Medical, and the ISM band is a frequency band allocated for general use in the industrial, scientific, and medical fields. However, either take measures to prevent electromagnetic wave leakage at the opening of the cavity resonator (installation of an electromagnetic wave absorber, design the opening in consideration of the cut-off frequency, or install a choke structure), or install the cavity resonator in a shielded space. If the electromagnetic wave radiation into space is suppressed by doing something like this, it will not be restricted by the ISM band.

In the microwave heating device 1 described above, when microwaves are supplied into the cavity resonator 11 to form a specific standing wave, a magnetic field is generated at the central axis C of the cavity resonator 11 and the magnetic field is The magnetic field can be maximized, and the magnetic field can be uniformly distributed in the direction of the central axis. Therefore, when the sheet 6 containing the object to be heated, which is made of a material with magnetic loss or a composite material containing a material with magnetic loss, is discharged from the supply port 12 through the central axis C and from the discharge port 13, the maximum temperature at the central axis C is It is possible to uniformly irradiate the magnetic field in the width direction of the sheet 6. Therefore, the material with magnetic loss generates heat due to the irradiation of the magnetic field.
In the heating described above, when the sheet 6 is formed of paper and an object to be heated made of a material with magnetic loss (conductive material) is placed on the paper, the object to be heated is heated, but the sheet of paper is 6 is not heated. Generally, paper contains moisture even when it is dry, and even when irradiated with a magnetic field, paper containing moisture does not generate an induced current, so it is not heated. On the other hand, the object to be heated is heated because an induced current is generated therein. In this way, the object to be heated can be selectively heated.
Note that at the portion of the cylinder center axis C, the electric field strength is minimal (see the electric field distribution diagram in FIG. 2(A)), and the magnetic field strength is maximal (see the magnetic field distribution diagram in FIG. 2(B)).

As explained above, the microwave heating device 1 uses the cylindrical cavity resonator 11 that forms a standing wave of the TM ₁₁₀ mode, for example, so that the magnetic field is concentrated on the central axis C. This becomes a maximum region, and the magnetic field strength becomes uniform in the direction of the central axis. Therefore, the temperature controllability (uniformity) of the object to be heated passing through the central axis C becomes high. Furthermore, by controlling the frequency and output of the microwaves that form the standing waves, a constant standing wave can be formed at all times, so temperature controllability is further improved and more uniform heating can be achieved.

The electromagnetic wave sensor 44 can accurately detect the frequency of the standing wave. Therefore, the frequency of the detected standing wave can be fed back to the microwave generator 21 to precisely control the frequency of the microwave supplied from the microwave generator 21. In this way, a standing wave can be stably generated within the cavity resonator 11. Therefore, the object to be heated can be efficiently and uniformly heated by the standing wave, and the state of formation of the standing wave within the cavity resonator can be stably maintained.

EXAMPLES The present invention will be described in more detail below based on Examples, but the present invention is not to be construed as being limited to these.

[Examples 1 to 3]
In each of Examples 1 to 3, commercially available resin sheet materials with a width of 8 cm having different surface resistivities shown in Table 1 were used as measurement samples. In Example 1, a transparent conductive sheet (Staclear NCF) whose base material was polyethylene terephthalate (PET) was used. In Example 2, the base material of the sheet material was a conductive bag made of polyolefin (added with carbon black). In Example 3, an antistatic aluminum vapor-deposited bag whose base material of the sheet material was PET was used. Then, using the microwave heating device 1 shown in FIG. 1, each sheet material was fixed in a magnetic field irradiation space with a width of 10 cm in a cylindrical cavity resonator 11, and magnetic field heating and dielectric heating were performed. For magnetic field heating, a TM ₁₁₀ mode standing wave was formed, and for dielectric heating, a TM ₀₁₀ mode standing wave was formed, and each measurement sample was fixed along the central axis. Both magnetic field heating and dielectric heating were performed at a microwave frequency in the range of 2.3 to 2.7 GHz and a microwave output in the range of 0 to 100 W. The same applies to Examples 4 to 7 and Comparative Examples.

[Comparative example 1]
On the other hand, as Comparative Example 1, a conductive file whose base material was polypropylene (PP) was used. The thickness and surface resistivity of each sheet are as listed in Table 1.
The heating results of Examples 1 to 3 and Comparative Example 1 are shown in Table 1.

表１において、誘電加熱が可能の場合にはＹ印、誘電加熱が不可の場合にはＮ印で示した。また磁界加熱が可能の場合にはＹ印、磁界加熱が不可の場合にはＮ印で示した。なお、誘電加熱に用いた空胴共振器と、磁界加熱に用いた空胴共振器では、異なる空胴共振器を用いており、それぞれの円筒共振器は円筒部内径が異なっている。

In Table 1, when dielectric heating is possible, it is marked Y, and when dielectric heating is not possible, it is marked N. Further, when magnetic field heating is possible, it is indicated by a Y symbol, and when magnetic field heating is not possible, it is indicated by an N symbol. Note that different cavity resonators are used for the cavity resonator used for dielectric heating and the cavity resonator used for magnetic field heating, and the inner diameters of the cylindrical portions of the respective cylindrical resonators are different.

The resin sheet materials of Examples 1 to 3 with low surface resistivities (10 ⁸ Ω/□ or less) cannot be heated by commonly used dielectric heating. On the other hand, it was found that magnetic field heating can be used for heating. In addition, to determine whether dielectric heating and magnetic field heating are possible, use the method described in paragraph [0033] above to check whether the resonance frequency of TM ₀₁₀ mode (possibility of dielectric heating) or TM ₁₁₀ mode (possibility of magnetic field heating) can be detected. That's what I decided.

[Example 4]
Next, in Example 4, the 8 cm wide sheet material of the antistatic aluminum vapor-deposited bag used in Example 3 was used as a measurement sample. While moving the measurement sample at a speed of 0.2 cm/s in a magnetic field irradiation (reaction) space with a width of 10 cm, the temperature change of the sheet material and the incident wave and reflection of the microwave heating device 1 are observed. Changes in waves and resonance frequency were measured using an electromagnetic wave sensor. The electromagnetic wave sensor used was one that could be measured as a DC signal using a loop antenna and a rectifier circuit using diodes. For temperature measurement, the temperature at the center of the sheet was measured using a radiation thermometer TMHX-CN0500 manufactured by Japan Sensor. For this magnetic field heating, a cavity resonator for TM ₁₁₀ mode was used, a standing wave of TM ₁₁₀ mode was formed, and the measurement sample was fixed along the central axis. The results are shown in FIG. Compared to the set temperature of 80°C, the temperature remained stable at 80±1°C. Further, as a result of measuring the temperature distribution in the width direction of the sheet material using the thermal image measuring device 41, it was confirmed that the entire sheet was heated uniformly (see FIG. 4).

[Examples 5-6]
In Example 5, a commercially available sheet-shaped conductive glass with a width of 8 cm shown in Table 2 was used as a measurement sample. In Example 6, a commercially available sheet-shaped conductive silicone rubber (mixed with carbon) having a width of 8 cm shown in Table 2 was used as a measurement sample. Then, using the microwave heating device 1 shown in FIG. 1, the measurement samples were fixed in a cavity resonator with a width of 10 cm and subjected to magnetic field heating and dielectric heating. on the other hand. Comparative Examples 5 and 6 used the same samples as Examples 5 and 6, except that the heating method was changed from magnetic field heating to dielectric heating. For magnetic field heating, a cavity resonator for TM ₁₁₀ mode is used and a standing wave of TM ₁₁₀ mode is formed, and for dielectric heating, a cavity resonator for TM ₀₁₀ mode is used and a standing wave for TM ₁₁₀ mode is used. A standing wave was formed, and each measurement sample was fixed along the central axis.
The heating results are shown in Table 2.

表２において、誘電加熱が可能の場合にはＹ印、誘電加熱が不可の場合にはＮ印で示した。また磁界加熱が可能の場合にはＹ印、磁化加熱が不可の場合にはＮ印で示した。

In Table 2, when dielectric heating is possible, it is marked Y, and when dielectric heating is not possible, it is marked N. Further, when magnetic field heating is possible, it is indicated by a Y symbol, and when magnetization heating is not possible, it is indicated by an N symbol.

As a result, it was found that dielectric heating, which is commonly used, cannot achieve heating. On the other hand, it was found that magnetic field heating can be used for heating. As with the heating of the resin sheet material, whether or not dielectric heating and magnetic field heating were possible was confirmed by checking whether standing microwave waves were formed in this microwave heating device. Furthermore, the results of heating conductive glass and conductive silicone rubber by changing the microwave output are shown in FIGS. 5 and 6, respectively. As a result of measuring the temperature at the center of the sheet using a radiation thermometer, it was confirmed that the higher the microwave output, the higher the temperature reached.

[Example 7]
The conductive paste was heated.
In Example 7, a measurement sample was prepared by applying conductive silver paste (manufactured by Toyochem Co., Ltd., product name: REXALPHA) to a size of 75 mm x 10 mm and a thickness of 0.05 mm on quartz glass. Ten minutes after coating, magnetic field heating was performed using the microwave heating device 1 shown in FIG. For magnetic field heating, a TM ₁₁₀ mode standing wave was formed. The measurement sample was placed at the center (including the central axis C) of the magnetic field irradiation space of the microwave heating device 1, and heated by magnetic field heating to a final temperature of 130° C. for 5 minutes. FIG. 7 shows the temperature change of the paste application part during heating, and the change in the incident wave, reflected wave, and resonance frequency of the microwave heating device. An electromagnetic wave sensor was used for these measurements. A loop antenna was used as the electromagnetic wave sensor. The temperature rose continuously, and the sudden temperature rise due to sparks in the conductive paste, which is a concern in dielectric heating, did not occur in magnetic field heating. As a result of measuring the temperature distribution of the entire paste application area during heating using the thermal image measuring device 41, it was confirmed that the paste was heated uniformly (FIG. 8). Further, in the appearance of each test piece shown in FIG. 9 before magnetic field heating (see figure (A)) and after heating (see figure (B)), no abnormally heated parts due to sparks were observed.

[Comparative Example 7]
In Comparative Example 7, a measurement sample similar to Example 7 was prepared. The measurement sample was heated in an electric furnace at 130° C. for 5 minutes and 30 minutes, and the electrical resistivity was measured at 5 locations within the paste application surface. Table 3 shows the results.

The electrical resistivity of the measurement sample subjected to microwave magnetic field heating showed approximately the same value at all five locations, and it can be said that the entire coated surface was heated uniformly. Comparing the results with electric furnace heating, it can be seen that the test piece heated by magnetic field can lower the electrical resistivity (higher conductivity) and has better heating efficiency.

[Comparative example 8]
Moreover, in Comparative Example 8, a conductive silver paste (manufactured by Toyochem Co., Ltd., product name: REXALPHA) was coated on a quartz glass to a size of 15 mm x 4 mm and a thickness of 0.05 mm to prepare a measurement sample. Ten minutes after application, it was placed at the center of the cavity resonator (including the central axis C), and dielectric heating was performed by forming a TM ₀₁₀ mode standing wave. FIG. 10 shows the temperature change of the paste application part during heating, and the change in the incident wave, reflected wave, and resonance frequency of the microwave heating device. The temperature rose to about 60° C. and then gradually decreased, and the resonant frequency increased as the temperature decreased. The electrical resistivity of the test piece after 100 seconds of dielectric heating was 0.13 Ω·cm, confirming that the electrical conductivity was inferior compared to magnetic field heating. In dielectric heating of a conductive paste, it is thought that as the conductivity increases, microwave absorption decreases and heating becomes difficult.

[Example 9-11]
Silicon substrates used as semiconductor materials (manufactured by Kojundo Chemical Research Institute, product name: silicon, 10 mm x 10 mm, thickness 1 mm), gallium nitride substrate (manufactured by Kojundo Chemical Research Institute, product name: gallium nitride, 10 mm x 10 mm, thickness) 2 mm) and an aluminum nitride substrate (manufactured by Kojundo Kagaku Kenkyujo Co., Ltd., product name: aluminum nitride (cylindrical), diameter 10 mm, thickness 2 mm) were heated using the microwave heating device 1 shown in FIG. The supply unit 31 shown in FIG. 1 was not used for the main heating, and a polyimide film (thickness: 125 μm) was placed at the same position as the sheet (object to be heated) 6 to hold the substrate, which was the object to be heated. . Note that since the polyimide film is neither a magnetic material nor a conductive material, it is not heated by microwaves. The substrate was placed on a polyimide film so as to coincide with the central axis position of the cavity resonator 11, and a predetermined microwave power was supplied from the microwave supply port 14 so as to form a _TM110 mode standing wave. The implementation conditions and results are shown in Table 4. Further, FIG. 11 shows the results of measuring the surface temperature of the silicon substrate using a radiation thermometer (manufactured by Japan Sensor, TMHX-CN0500) when 100 W of microwave power was supplied to the silicon substrate. It was found that the temperature could be heated to 300°C after 31 seconds from 30°C. This indicates that the heating operation of the semiconductor material is appropriate. Similarly, a gallium nitride substrate can be heated from 30°C to 300°C in 25 seconds with 100W microwave irradiation, and an aluminum nitride substrate can be heated from 30°C to 56°C in 300 seconds with 100W microwave irradiation. I was able to do that.

1 Microwave heating device 6 Sheet (object to be heated)
11 Cavity resonator 12 Supply port 13 Discharge port 14 Microwave supply port (coaxial waveguide converter type microwave supply port)
21 Microwave generator 22 Microwave amplifier 23 Isolator 24 Matching box 25 Antenna 26 Cable 31 Supply section 31A Supply side conveyance section 31B Sending side conveyance section 41 Thermal image measuring device 42, 45, 46 Cable 42 Controller 44 Electromagnetic wave sensor C Sky Torso center axis (center axis)

Claims (10)

A cavity resonator that is a polygonal cylinder-shaped microwave irradiation space with two parallel faces centered on the cylinder center axis, excluding cylinders or cylinders whose cross section in the direction perpendicular to the cylinder center axis is rectangular;
An object to be heated made of a magnetic material, a material with magnetic loss, or an electrically conductive material, or a magnetic material, a material with magnetic loss, or an electrically conductive material is placed in a space where the energy distribution of the magnetic field within the cavity resonator is uniform. a supply unit that supplies a heated object made of a composite material containing a certain material through a magnetic field irradiation space where the magnetic field strength of the cavity resonator is maximum and uniform and the electric field strength is minimum;
A standing wave formed inside the microwave irradiation space is a TM ₁₁₀ mode or a TM ₃₁₀ mode, and the magnetic field irradiation space is aligned along a cylindrical central axis of the cavity resonator and coincides with the cylindrical central axis. It is a space,
A microwave heating device that heats the object to be heated supplied by the supply unit in the magnetic field irradiation space. The microwave heating device according to claim 1, wherein the standing wave formed inside the microwave irradiation space is a TM ₁₁₀ mode. The means for forming the TM ₁₁₀ mode standing wave is configured to maintain a uniform distribution state of the magnetic field along the central axis of the cylinder at all times when the object to be heated is inserted into the microwave irradiation space. The microwave heating device according to claim 2, further comprising a mechanism for controlling the frequency of the waves. The mechanism for controlling the frequency of the microwave detects a resonant frequency that matches a standing wave of TM ₁₁₀ mode that varies depending on the insertion state of the object to be heated, and irradiates the microwave that matches the resonant frequency. The microwave heating device according to claim 3. The means for detecting a resonant frequency that matches the standing wave of the TM ₁₁₀ mode has a mechanism that measures reflected waves from the microwave irradiation space, and determines the frequency at which the reflected waves are minimum based on the measurement signal. 5. The microwave heating device according to claim 4, further comprising a mechanism for controlling the frequency of the microwave for detecting a resonance frequency. The means for detecting the resonant frequency matching the standing wave of the TM ₁₁₀ mode has a mechanism for measuring the energy state in the microwave irradiation space, and detects the energy state in the microwave irradiation space based on the measurement signal. 5. The microwave heating device according to claim 4, further comprising a mechanism for controlling the frequency of the microwave for detecting the resonance frequency from the frequency at which the density is maximum. 7. The method according to claim 1, wherein a magnetic field that reaches a maximum at the center axis of the cylinder of the cavity resonator is applied to generate an induced current in the object to be heated, thereby heating the object to be heated. Microwave heating device as described. The microwave heating device according to any one of claims 1 to 7, wherein the microwave heating device is a chemical reaction device that heats the object to be heated using microwaves to cause a chemical reaction. A heating method using the microwave heating device according to any one of claims 1 to 8. A chemical reaction method using the microwave heating device according to any one of claims 1 to 8, the method comprising causing a chemical reaction by heating the object to be heated.

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