Microwave heating device

Abstract

The present invention addresses the problem of more uniformly heating, by using microwaves, an object to be heated. A microwave heating device (100) comprises an oscillator (1) and a resonator (2). A first wall part (211) and a second wall part (212) of the resonator (2) form standing waves in a predetermined direction (D1) by reflecting microwaves. In the resonator (2), an object to be heated (TA1) is disposed in a predetermined range of an internal space (SP1). The predetermined range is a range between a first position (P11) and a second position (P12) in the predetermined direction. A separation distance (X1), which is at least one of a distance between the first position (P11) and the first wall part (211) in the predetermined direction (D1) and a distance between the second position (P12) and the second wall part (212) in the predetermined direction (D1), is greater than or equal to one-quarter the wavelength of a microwave when the frequency of the microwave is the center frequency of a predetermined frequency band.

Description

Microwave heating device

[0001] This disclosure relates in general to microwave heating apparatuses. More specifically, this disclosure relates to microwave heating apparatuses comprising an oscillator for generating microwaves.

[0002] Patent Document 1 discloses a microwave drying apparatus comprising a conveying means, a drying oven, and a microwave oscillator. The conveying means conveys the object to be heated along a predetermined path. The drying oven is arranged so as to intersect with the conveying means on the predetermined path and heats the object to be heated with microwaves. The microwave oscillator is arranged on one end of the drying oven and irradiates microwaves from one end to the other.

[0003] The microwave drying apparatus (microwave heating apparatus) described in Patent Document 1 includes a movable shorting plate that reciprocates along the direction of microwave irradiation when irradiating an object to be heated with microwaves, in order to heat the object to be heated uniformly. However, since the microwaves are reflected at the fixed end by the movable shorting plate, there is a problem in that it is difficult to heat the object to be heated uniformly in the vicinity where the movable shorting plate is installed in the drying oven.

[0004] Japanese Patent Publication No. 2021-125447

[0005] The object of this disclosure is to provide a microwave heating apparatus that can heat an object to be heated more uniformly using microwaves.

[0006] A microwave heating apparatus according to one aspect of the present disclosure comprises an oscillator and a resonator. The oscillator generates microwaves for heating an object to be heated, and the frequency of the microwaves can be changed within a predetermined frequency band. The resonator has an internal space and two walls, and the object to be heated is placed in a predetermined range of the internal space. The microwaves are supplied to the internal space. The two walls cause standing waves to form in a predetermined direction by reflecting the microwaves. The predetermined range is the range between a first position and a second position in the predetermined direction. When the wall closer to the first position is designated as the first wall and the wall closer to the second position is designated as the second wall, the separation distance, which is at least one of the distance between the first position and the first wall in the predetermined direction and the distance between the second position and the second wall in the predetermined direction, is 1 / 4 or more of the wavelength of the microwaves when the frequency of the microwaves is the center frequency of the predetermined frequency band.

[0007] Figure 1 is a schematic cross-sectional view of a microwave heating device according to Embodiment 1. Figure 2 is a graph showing multiple standing waves formed in the internal space of a resonator in the same microwave heating device. Figure 3 is a schematic configuration diagram of the oscillator provided in the same microwave heating device. Figure 4 is a schematic cross-sectional view of a microwave heating device according to a first modification of Embodiment 1. Figure 5 is a schematic cross-sectional view of a microwave heating device according to a second modification of Embodiment 1. Figure 6 is a schematic cross-sectional view of a microwave heating device according to a third modification of Embodiment 1. Figure 7 is a schematic configuration diagram of the oscillator provided in the microwave heating device of Embodiment 1, different from the configuration shown in Figure 3. Figure 8 is a schematic configuration diagram of the oscillator provided in the microwave heating device of Embodiment 1, different from the configurations shown in Figures 3 and 7. Figure 9 is a plan view of a microwave heating device according to Embodiment 2. Figure 10 is a schematic cross-sectional view of the same microwave heating device along the line A1-A1 in Figure 9. Figure 11 is a schematic plan view of a microwave heating device according to a first modification of Embodiment 2. Figure 12 is a schematic plan view of a microwave heating device according to a second modification of Embodiment 2. Figure 13 is a schematic plan view of a microwave heating device according to a third modification of Embodiment 2. Figure 14 is a schematic cross-sectional view of the microwave heating device of Embodiment 2 when the resonator has a choke structure. Figure 15 is a schematic plan view of a microwave heating device according to Embodiment 3. Figure 16 is a schematic plan view of a microwave heating device according to a first modification of Embodiment 3. Figure 17 is a schematic plan view of a microwave heating device according to a second modification of Embodiment 3. Figure 18 is a schematic plan view of a microwave heating device according to a third modification of Embodiment 3.

[0008] The embodiments and modifications described below are merely examples of the present disclosure. This disclosure is not limited to these embodiments and modifications, and various modifications are possible depending on the design, etc., as long as they do not depart from the technical idea of ​​the present disclosure. The figures described in the embodiments and modifications below are schematic diagrams, and the ratios of the size and thickness of each component in the figures do not necessarily reflect the actual dimensional ratios.

[0009] (1) Embodiment 1 (1-1) Overview Below, an overview of the microwave heating apparatus 100 according to Embodiment 1 will be described with reference to Figures 1 to 2.

[0010] The microwave heating apparatus 100 according to Embodiment 1 comprises an oscillator 1 and a resonator 2, as shown in Figure 1. The oscillator 1 generates microwaves to heat the object to be heated TA1. The oscillator 1 can change the frequency of the microwaves within a predetermined frequency band. The resonator 2 has an internal space SP1 and two wall portions 21. Microwaves are supplied to the internal space SP1. The two wall portions 21 reflect the microwaves, thereby forming (generating) standing waves in a predetermined direction D1. In the resonator 2, the object to be heated TA1 is placed within a predetermined range of the internal space SP1. The above predetermined range is the range between a first position P11 and a second position P12 in a predetermined direction D1. The wall portion closer to the first position P11 of the two wall portions 21 is designated as the first wall portion 211, and the wall portion closer to the second position P12 of the two wall portions 21 is designated as the second wall portion 212. In Embodiment 1, the first position P11 is the position where the first end of the object to be heated TA1 in a predetermined direction D1 is positioned. On the other hand, in Embodiment 1, the second position P12 is the position where the second end of the object to be heated TA1 in a predetermined direction D1 is positioned.

[0011] The separation distance X1, which is the distance X1a between the first position P11 in a predetermined direction D1 and the first wall portion 211 located at position P0 in a predetermined direction D1, is 1 / 4 or more of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band. Similarly, the separation distance X1b, which is the distance X1b between the second position P12 in a predetermined direction D1 and the second wall portion 212 located at position P2 in a predetermined direction D1, is 1 / 4 or more of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band. In this disclosure, "the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band" refers to the wavelength of the microwave when the oscillator 1 generates a microwave that is the center frequency of a predetermined frequency band.

[0012] In the internal space SP1 of the resonator 2, multiple standing waves (see graphs G11 to G1n in Figure 2) are formed between the first wall 211 and the second wall 212. Graphs G11 to G1n in Figure 2 show the relationship between the position in a predetermined direction D1 and the electric field strength (or the amplitude corresponding to the electric field strength). The horizontal axis of graphs G11 to G1n shows the position in the predetermined direction D1, and the vertical axis shows the amplitude. In the multiple standing waves, the positions of the antinodes and nodes differ depending on the frequency of the microwaves generated by the oscillator 1. The amount of heating due to the part corresponding to the antinode position in each of the multiple standing waves is larger than the amount of heating due to other parts (for example, the part corresponding to the node position). Graph G2 is a schematic graph that superimposes the absolute values ​​of the amplitudes of the multiple standing waves. The horizontal axis of graph G2 shows the position in the predetermined direction D1, and the vertical axis shows the absolute value of the amplitude. Note that displaying the absolute values ​​of the amplitudes for all the standing waves shown in graphs G11 to G1n would be cumbersome. Therefore, in graph G2, as an example, the absolute values ​​of the amplitudes for the standing waves shown in graphs G11 to G15 are displayed in a simplified manner. Graph G3 is a graph showing the values ​​obtained by integrating graph G2 at predetermined widths along a predetermined direction D1, along the predetermined direction D1. The horizontal axis of graph G3 indicates the position in the predetermined direction D1, and the vertical axis of graph G3 indicates an index of the amount of heating by microwaves. The amount of heating by microwaves in the internal space SP1 is proportional to graph G3. As shown in graph G3, near the first wall portion 211 and the second wall portion 212, there are peaks and dips in the amount of heating by microwaves, indicating large variations in the amount of heating by microwaves. In this disclosure, "the vicinity of the first wall portion 211 and the second wall portion 212" means that the distance from the first wall portion 211 or the second wall portion 212 in a predetermined direction D1 is shorter than 1 / 4 of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band. On the other hand, as shown in graph G3, the variation in the amount of heating by microwaves is small in the central portion between the first wall portion 211 and the second wall portion 212 in a predetermined direction D1.In this disclosure, the "central portion between the first wall portion 211 and the second wall portion 212" refers, more specifically, to the portion that is at least one-quarter of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band, from each of the first wall portion 211 and the second wall portion 212. In other words, the "central portion between the first wall portion 211 and the second wall portion 212" is the central space of the internal space SP1 in a predetermined direction D1. In the central space, the distance from the first wall portion 211 and the distance from the second wall portion 212 in the predetermined direction D1 are at least one-quarter of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band.

[0013] As described above, in the microwave heating device 100 of Embodiment 1, the separation distance X1 is 1 / 4 or more of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band. Therefore, the object to be heated TA1 can be heated in the central part where the variation in the amount of heating by the microwave is small. As a result, the microwave heating device 100 of Embodiment 1 has the advantage of being able to heat the object to be heated TA1 more uniformly using microwaves.

[0014] (1-2) Detailed Configuration (1-2-1) Overall Configuration Below, the detailed configuration of the microwave heating apparatus 100 of Embodiment 1 will be described with reference to Figures 1 to 3.

[0015] In the following example, we will define three mutually orthogonal axes: the X, Y, and Z axes. The axis parallel to the thickness direction of the object to be heated TA1 will be defined as the "Y axis." Furthermore, one of the two directions along the Y axis will be defined as the forward direction, and the other as the backward direction. Note that the X, Y, and Z axes are all virtual axes, and the arrows indicating "X," "Y," and "Z" in the drawings are merely illustrative and do not represent actual axes. Also, these directions are not intended to limit the direction in which the microwave heating device 100 can be used.

[0016] The microwave heating device 100 is used when microwave-heating an object to be heated TA1 (see FIG. 1) containing a dielectric. As an example, the microwave heating device 100 is used when microwave-heating the object to be heated TA1 for the purpose of drying the object to be heated TA1 impregnated with a solvent or firing a green sheet as a raw material of a ceramic device.

[0017] As shown in FIG. 1, the microwave heating device 100 includes an oscillator 1, a resonator 2, and a control device 9.

[0018] (1-2-2) Oscillator The oscillator 1 generates microwaves for heating the object to be heated TA1 and can change the frequency of the microwaves within a predetermined frequency band. The oscillator 1 performs a frequency sweep within the predetermined frequency band in accordance with the control by the control device 9. The oscillator 1 of Embodiment 1 is disposed on the first wall portion 211 of the resonator 2.

[0019] As shown in FIG. 3, the oscillator 1 of Embodiment 1 includes an oscillation unit 11, an isolator 12, and an output unit 13.

[0020] The oscillation unit 11 oscillates (generates) microwaves to be supplied to the internal space SP1 of the resonator 2. As an example, the oscillation unit 11 is a microwave generator such as a magnetron. Also, the oscillation unit should be a microwave generator using a semiconductor element.

[0021] The isolator 12 suppresses the influence of the reflected waves generated in the internal space SP1 of the resonator 2. More specifically, the isolator 12 allows the microwaves oscillated by the oscillation unit 11 to be directly propagated to the resonator 2 and absorbs the reflected waves so that they do not return to the oscillation unit 11. As a result, the isolator 12 protects the oscillation unit 11. Thereby, the oscillator can supply microwaves to the internal space SP1 of the resonator 2 stably.

[0022] The isolator 12, for example, includes a main body 121 and a termination resistor 122. The first terminal of the main body 121 is connected to the oscillator 11, and the second terminal of the main body 121 is connected to the output 13. The third terminal of the main body 121 is connected to the termination resistor 122, and the reflected wave is absorbed by the termination resistor 122.

[0023] The output unit 13 supplies (outputs) microwaves propagated via the isolator 12 to the internal space SP1 of the resonator 2. In the embodiment 1, the output unit 13 is connected to the opening 22 of the first wall portion 211 of the resonator 2, which will be described later.

[0024] (1-2-3) Resonator The resonator 2 guides (transmits) the microwaves supplied from the oscillator 1. The resonator 2 is rectangular in shape. However, the resonator 2 may be hollow cylindrical, hollow spherical, or other hollow polygonal prism, and its shape is not limited. The resonator 2 is made of a conductive material, such as copper, iron, or aluminum.

[0025] The hollow resonator 2 has an internal space (cavity) SP1, as shown in Figure 1. Microwaves are supplied to the internal space SP1 from the oscillator 1. The internal space SP1 is a rectangular parallelepiped space. However, the internal space SP1 may also be cylindrical, spherical, or other polygonal prism-shaped space, and the shape of the internal space SP1 is not limited.

[0026] The resonator 2 has two wall portions 21 that resonate in a predetermined direction D1 by reflecting microwaves supplied to the internal space SP1, thereby forming (generating) a standing wave. The microwaves supplied to the internal space SP1 are reflected by the inner surfaces of the two wall portions 21. The two wall portions 21 are a first wall portion 211 and a second wall portion 212. The predetermined direction D1 is the X-axis direction.

[0027] Microwaves supplied to the internal space SP1 are reflected by the first wall 211 and the second wall 212, causing them to resonate in a predetermined direction D1 and form a standing wave. For example, in the internal space SP1, if the distance from the first wall 211 to the second wall 212 in a predetermined direction D1 is an integer multiple of half the wavelength of the microwaves supplied from the oscillator 1, the microwaves resonate in the predetermined direction D1 and form a standing wave.

[0028] In the resonator 2 of Embodiment 1, an opening 22 is provided in the first wall portion 211. The internal space SP1 is connected to the oscillator 1 through the opening 22 of the first wall portion 211. In short, microwaves generated by the oscillator 1 are supplied to the internal space SP1 through the opening 22 of the first wall portion 211. The opening 22 is, for example, rectangular. However, the opening 22 may also be circular, and its shape is not limited.

[0029] In the resonator 2, the object to be heated TA1 is placed within a predetermined range of the internal space SP1. Microwaves supplied to the internal space SP1, which form standing waves, heat the object to be heated TA1 placed within the predetermined range. The predetermined range is the range between a first position P11 and a second position P12 in a predetermined direction D1. In Embodiment 1, the first position P11 is the position where the first end of the object to be heated TA1 is placed in the predetermined direction D1. On the other hand, in Embodiment 1, the second position P12 is the position where the second end of the object to be heated TA1 is placed in the predetermined direction D1.

[0030] The first separation distance X1, which is the distance X1a between the first position P11 and the first wall portion 211 (position P0 shown in Figure 1) in a predetermined direction D1, is 1 / 4 or more of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band. Similarly, the first separation distance X1, which is the distance X1b between the second position P12 and the second wall portion 212 (position P2 shown in Figure 1) in a predetermined direction D1, is 1 / 4 or more of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band. As a result, the object to be heated TA1 can be heated within a range where the variation in the amount of heating by microwaves in the internal space SP1 is small. As a result, the microwave heating device 100 of Embodiment 1 has the advantage of being able to heat the object to be heated TA1 more uniformly using microwaves.

[0031] The first separation distance X1, which is the distance X1a between the first position P11 and the first wall portion 211 in a predetermined direction D1, satisfies the following equation (1). Similarly, the first separation distance X1, which is the distance X1b between the second position P12 and the second wall portion 212 in a predetermined direction D1, satisfies the following equation (1).

[0032] X1 ≥ λf ０ / 4w formula (1)

[0033] Note that in equation (1), "f ０ " is the center frequency of a predetermined frequency band in which the oscillator 1 can change the microwave frequency. Also, in equation (1), "λ" is the center frequency f ０ This is the wavelength of the microwave when [condition]. Also, "w" in equation (1) is the width of a predetermined frequency band in which the oscillator 1 can change the microwave frequency. With the above configuration, the object to be heated TA1 can be heated more reliably within a range where the variation in the amount of heating by microwaves in the internal space SP1 is small. As a result, the microwave heating device 100 of Embodiment 1 has the advantage of being able to heat the object to be heated TA1 more reliably and uniformly using microwaves.

[0034] (1-2-4) Control device The control device 9 controls the oscillator 1. More specifically, the control device 9 controls the oscillator 1 to perform a frequency sweep in a predetermined frequency band, thereby moving the positions of the antinodes and nodes of the standing waves formed in the internal space SP1. In this disclosure, "moving the positions of the antinodes and nodes of the standing waves" means changing the position where the antinodes and nodes of the standing waves are formed by changing the spacing (wavelength) of the standing waves formed in the internal space SP1 of the resonator 2 in the waveguide direction described above.

[0035] The control device 9 preferably includes a computer system. In the computer system, some or all of the functions of the control device 9 are realized by a processor such as a CPU or MPU reading and executing a program stored in memory. The computer system mainly includes a processor that operates according to the program as its hardware configuration. The type of processor is not limited as long as it can realize its functions by executing a program. The processor consists of one or more electronic circuits, including a semiconductor integrated circuit (IC) or an LSI (Large Scale Integration). Here, we refer to them as ICs and LSIs, but the name changes depending on the degree of integration, and they may also be called system LSIs, VLSIs (Very Large Scale Integrations), or ULSIs (Ultra Large Scale Integrations). Field-programmable gate arrays (FPGAs) that are programmed after the manufacture of the LSI, or reconfigurable logic devices that allow for the reconfiguration of junction relationships within the LSI or the setup of circuit compartments within the LSI, can also be used for the same purpose. Multiple electronic circuits may be integrated on a single chip or provided on multiple chips. Multiple chips may be integrated into a single device, or they may be provided in multiple devices.

[0036] (1-3) Advantages In the microwave heating apparatus 100 of Embodiment 1, the first separation distance X1, which is the distance X1a between the first position P11 and the first wall portion 211 (or position P0) in a predetermined direction D1, is 1 / 4 or more of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band. Similarly, the first separation distance X1, which is the distance X1b between the second position P12 and the second wall portion 212 (or position P2) in a predetermined direction D1, is 1 / 4 or more of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band.

[0037] In the internal space SP1 of the resonator 2, multiple standing waves (see graphs G11 to G1n in Figure 2) are formed between the first wall 211 and the second wall 212, with different positions of antinodes and nodes depending on the frequency of the microwaves generated by the oscillator 1. The amount of heating due to the portion corresponding to the antinode position in each of the above multiple standing waves is larger than the amount of heating due to other portions (for example, portions corresponding to the node position). The amount of heating due to microwaves in the internal space SP1 is proportional to the heating amount index in graph G3. As shown in graph G3, in the vicinity of the first wall 211 and the second wall 212, there are peaks and dips in the amount of heating due to microwaves, and the variation in the amount of heating due to microwaves is large. On the other hand, as shown in graph G3, in the central portion between the first wall 211 and the second wall 212, the variation in the amount of heating due to microwaves is small.

[0038] As described above, the microwave heating device 100 of Embodiment 1 can heat the object to be heated TA1 in the central part where the variation in the amount of heating by microwaves is small. As a result, the microwave heating device 100 of Embodiment 1 can heat the object to be heated TA1 more uniformly using microwaves. According to the microwave heating device 100 of Embodiment 1, by supplying uniform microwave energy to the entire object to be heated TA1, uneven heating is suppressed and efficient heating can be achieved.

[0039] In the microwave heating apparatus 100 of Embodiment 1, the first separation distance X1, which is the distance X1a between the first position P11 and the first wall portion 211 in a predetermined direction D1, satisfies the above formula (1). Similarly, the first separation distance X1, which is the distance X1b between the second position P12 and the second wall portion 212 in a predetermined direction D1, satisfies the above formula (1).

[0040] This allows for more reliable heating of the object to be heated TA1 within a range where the variation in the amount of heating by microwaves in the internal space SP1 is small. As a result, the microwave heating device 100 of Embodiment 1 has the advantage of being able to more reliably and uniformly heat the object to be heated TA1 using microwaves.

[0041] (1-4) Modifications of Embodiment 1 Embodiment 1 described above is only one of many embodiments of the present disclosure. Embodiment 1 described above can be modified in various ways depending on the design, etc., as long as the objectives of the present disclosure are achieved. The following modifications may be implemented by combining them as appropriate. Components similar to those in Embodiment 1 described above are denoted by the same reference numerals and their description is omitted.

[0042] (1-4-1) First Modified Example of Embodiment 1 The microwave heating device 100A of the first modified example of Embodiment 1, as shown in Figure 4, comprises an oscillator 1, a resonator 2, a control device 9, and a coupling circuit mechanism 5. The coupling circuit mechanism 5 is positioned between the oscillator 1 and the resonator 2 and adjusts the coupling strength between the oscillator 1 and the resonator 2. As an example, the coupling circuit mechanism 5 has an opening hole that connects the oscillator 1 (or output unit 13) and the opening 22 of the first wall portion 211 of the resonator 2, and is a mechanism that can arbitrarily adjust the dimensions of the above-mentioned opening hole. The coupling circuit mechanism 5 is connected to both the oscillator 1 (or output unit 13) and the opening 22 of the first wall portion 211 of the resonator 2. The coupling circuit mechanism 5 is a so-called iris.

[0043] In the first modified microwave heating apparatus 100A, the second separation distance X21 between a predetermined range (or first position P11) in a predetermined direction D1 and the coupling circuit mechanism 5 is 1 / 4 or more of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band.

[0044] More specifically, in the first modified microwave heating device 100A, the second separation distance X21 between a predetermined range (or first position P11) in a predetermined direction D1 and the coupling circuit mechanism 5 satisfies the following equation (2).

[0045] X21 ≥ λf ０ / 4w formula (2)

[0046] Note that in equation (2), "f ０ " is the center frequency of a predetermined frequency band in which the oscillator 1 can change the microwave frequency. Also, in equation (2), "λ" is the center frequency f ０ This is the wavelength of the microwave when [condition]. Also, "w" in equation (2) is the width of a predetermined frequency band in which the oscillator 1 can change the microwave frequency.

[0047] In the first modified microwave heating device 100A, the first separation distance X1 between a predetermined range (or second position P12) in a predetermined direction D1 and the second wall portion 212 satisfies the above-described formula (1), similar to the microwave heating device 100 of Embodiment 1 described above.

[0048] In the first modified microwave heating device 100A, the transmission efficiency of microwaves from the oscillator 1 to the resonator 2 is optimized, improving the heating efficiency. Therefore, the first modified microwave heating device 100A has the advantage of being able to heat the object to be heated TA1 more uniformly using microwaves while improving heating efficiency.

[0049] (1-4-2) Second Modification of Embodiment 1 The microwave heating device 100B of the second modification of Embodiment 1, as shown in Figure 5, comprises an oscillator 1, a resonator 2, a control device 9, a coupling circuit mechanism 5, and a matching device 6. The coupling circuit mechanism 5 is positioned between the oscillator 1 and the resonator 2 and adjusts the coupling strength between the oscillator 1 and the resonator 2. The matching device 6 is positioned between the oscillator 1 and the coupling circuit mechanism 5. The matching device 6 matches the impedance of the oscillator 1 with the impedance of the resonator 2 and the impedance of the coupling circuit mechanism 5. The "impedance of the resonator 2" as referred to in this disclosure changes depending on the conditions of the internal space SP1 of the resonator 2 (i.e., the shape, material, etc. of the object to be heated TA1 placed in the internal space SP1).

[0050] In the second modified microwave heating device 100B, the second separation distance X21 between a predetermined range (or first position P11) in a predetermined direction D1 and the coupling circuit mechanism 5 satisfies equation (2) above, similar to the first modified microwave heating device 100A described above. Also, in the second modified microwave heating device 100B, the first separation distance X1 between a predetermined range (or second position P12) in a predetermined direction D1 and the second wall portion 212 satisfies equation (1) above, similar to the microwave heating device 100 of Embodiment 1 described above.

[0051] In the second modified microwave heating device 100B, the transmission efficiency of microwaves from the oscillator 1 to the resonator 2 is optimized, resulting in improved heating efficiency. Therefore, the second modified microwave heating device 100B has the advantage of being able to heat the object to be heated TA1 more uniformly using microwaves while further improving heating efficiency.

[0052] (1-4-3) Third Modification of Embodiment 1 The microwave heating device 100C of the third modification of Embodiment 1 comprises an oscillator 1, a resonator 2, a control device 9, and a matching unit 6, as shown in Figure 6. The matching unit 6 matches the impedance of the oscillator 1 with the impedance of the resonator 2. The matching unit 6 is connected to both the oscillator 1 (or output unit 13) and the opening 22 of the first wall portion 211 of the resonator 2.

[0053] In the third modified microwave heating apparatus 100C, the second separation distance X22 between a predetermined range (or first position P11) in a predetermined direction D1 and the matching unit 6 is 1 / 4 or more of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band.

[0054] In the third modified microwave heating apparatus 100C, the second separation distance X22 between a predetermined range (or first position P11) in a predetermined direction D1 and the matching unit 6 satisfies the following equation (3).

[0055] X²² ≥ λf ０ / 4w formula (3)

[0056] Note that in equation (3), "f ０"f" is the center frequency of a predetermined frequency band in which the oscillator 1 can change the frequency of the microwave. Further, "λ" in Equation (3) is the wavelength of the microwave when the frequency of the microwave is the above center frequency f ０ at that time. Further, "w" in Equation (3) is the width of a predetermined frequency band in which the oscillator 1 can change the frequency of the microwave.

[0057] In the microwave heating apparatus 100C of the third modification, the first separation distance X1 between the predetermined range (or the second position P12) in the predetermined direction D1 and the second wall portion 212 satisfies the above-described Equation (1) in the same manner as the microwave heating apparatus 100 of the above-described Embodiment 1.

[0058] In the microwave heating apparatus 100C of the third modification, the transmission efficiency of the microwave from the oscillator 1 to the resonator 2 is optimized, and the heating efficiency is improved. For this reason, the microwave heating apparatus 100C of the third modification has an advantage that it can improve the heating efficiency while heating the object to be heated TA1 more uniformly using microwaves.

[0059] (1-4-4) Other modifications of Embodiment 1 Hereinafter, other modifications of the above-described Embodiment 1 will be listed.

[0060] In the above-described Embodiment 1, the separation distance X1, which is the distance X1a between the first position P11 and the first wall portion 211 in the predetermined direction D1, is 1 / 4 or more of the wavelength of the microwave when the frequency of the microwave is the center frequency of the predetermined frequency band. Similarly, the separation distance X1, which is the distance X1b between the second position P12 and the second wall portion 212 in the predetermined direction D1, is 1 / 4 or more of the wavelength of the microwave when the frequency of the microwave is the center frequency of the predetermined frequency band. However, it is sufficient that at least one of the separation distances X1, that is, the distance X1a between the first position P11 and the first wall portion 211 in the predetermined direction D1 and the distance X1b between the second position P12 and the second wall portion 212 in the predetermined direction D1, is 1 / 4 or more of the wavelength of the microwave when the frequency of the microwave is the center frequency of the predetermined frequency band.

[0061] The oscillator 1 may further include a directional coupler 14, an output detection unit 15, and a termination resistor 16, as shown in Figure 7. The directional coupler 14 monitors the microwaves supplied to the internal space SP1 of the resonator 2. The directional coupler 14 is positioned between the isolator 12 and the output unit 13. The output detection unit 15 is connected to the directional coupler 14 and detects the microwaves supplied to the internal space SP1 of the resonator 2. The output detection unit 15 is, for example, a power detection circuit. The termination resistor 16 is connected to the directional coupler 14 and absorbs reflected waves generated in the internal space SP1 of the resonator 2.

[0062] Furthermore, as shown in Figure 8, the oscillator 1 may have a reflection detection unit 17 instead of a termination resistor 16. In this case, the directional coupler 14 monitors both the microwave supplied to the internal space SP1 of the resonator 2 and the reflected waves generated in the internal space SP1. The reflection detection unit 17 is connected to the directional coupler 14 and detects the reflected waves generated in the internal space SP1. The reflection detection unit 17 is, for example, a power detection circuit.

[0063] The microwave heating apparatus 100 according to Embodiment 1, and the microwave heating apparatus according to each modified example of Embodiment 1, may also be used for firing ceramic devices molded into a green sheet shape, or for curing other plastic devices.

[0064] (2) Embodiment 2 (2-1) Overview Next, an overview of the microwave heating apparatus 100D according to Embodiment 2 will be described with reference to Figure 9. Components similar to those in Embodiment 1 are denoted by the same reference numerals and their descriptions are omitted.

[0065] In the microwave heating apparatus 100D of Embodiment 2, as shown in Figure 9, the object to be heated TA2 is in the shape of a sheet, and a slot 23 is formed in the resonator 2A between the first wall portion 211 and the second wall portion 212, through which the object to be heated TA2 is inserted from an insertion direction (Z-axis direction) perpendicular to a predetermined direction D1 and through which the object to be heated TA2 passes. The predetermined range through which the object to be heated TA2 passes (or is positioned) is the range between the first position P11 and the second position P12 in the predetermined direction D1. The first position P11 in Embodiment 2 is the position through which the first end of the object to be heated TA2 on the first wall portion 211 side passes when the object to be heated TA2 inserted in the slot 23 is closest to the first wall portion 211 side. On the other hand, the second position P12 in the second embodiment is the position where the second end of the object to be heated TA2 on the second wall portion 212 side passes when the object to be heated TA2 inserted in the slot 23 is closest to the second wall portion 212 side.

[0066] In the microwave heating apparatus 100D of Embodiment 2, the predetermined range through which the object to be heated TA2 passes is in the projection region of the slot 23 in the insertion direction (Z-axis direction). That is, when viewed from the Y-axis direction, the first position P11 roughly coincides with the first end of the slot 23 in the predetermined direction D1. Also, when viewed from the Y-axis direction, the second position P12 roughly coincides with the second end of the slot 23 in the predetermined direction D1.

[0067] The microwave heating device 100D of Embodiment 2 differs from the microwave heating device 100 of Embodiment 1 in the above respects.

[0068] (2-2) Detailed Configuration (2-2-1) Overall Configuration Below, the detailed configuration of the microwave heating apparatus 100D of Embodiment 2 will be described with reference to Figures 9 and 10.

[0069] As shown in Figure 9, the microwave heating device 100D comprises an oscillator 1, a resonator 2A, and a control device 9.

[0070] (2-2-2) Resonator The resonator 2A guides (transmits) the microwaves supplied from the oscillator 1. As shown in Figures 9 and 10, the resonator 2A is a rectangular waveguide. The resonator 2A is rectangular when viewed from the Y-axis direction. The dimension of the resonator 2A in the X-axis direction is larger than the dimensions in the Y-axis direction and the Z-axis direction, respectively. The resonator 2A is made of a conductive material, such as copper, iron, or aluminum. The resonator 2A may be a hollow cylindrical, hollow spherical, or other hollow polygonal prism waveguide, and the shape of the resonator 2A is not limited.

[0071] The resonator 2A is a hollow tube having an internal space (cavity) SP1. The resonator 2A guides microwaves in the internal space SP1. The direction in which the resonator 2A guides microwaves is the longitudinal direction of the resonator 2A, that is, the X-axis direction. The internal space SP1 is a rectangular parallelepiped space. The internal space SP1 may also be cylindrical, spherical, or other polygonal prism-shaped space, and its shape is not limited.

[0072] The resonator 2A has two wall portions 21 that resonate microwaves in a predetermined direction D1 by reflecting microwaves supplied to the internal space SP1, thereby forming (generating) standing waves. The microwaves supplied to the internal space SP1 are reflected by the inner surfaces of the two wall portions 21. The two wall portions 21 are a first wall portion 211 and a second wall portion 212. The predetermined direction D1 is the X-axis direction.

[0073] Microwaves supplied to the internal space SP1 are reflected by the first wall 211 and the second wall 212, causing them to resonate in a predetermined direction D1 and form a standing wave. For example, when the distance between the first wall 211 and the second wall 212 in the predetermined direction D1 is an integer multiple of half the wavelength of the microwaves supplied from the oscillator 1, the microwaves resonate in the predetermined direction D1 and form a standing wave.

[0074] In the resonator 2A of Embodiment 2, an opening 22 is provided in the first wall portion 211. The internal space SP1 is connected to the oscillator 1 through the opening 22 of the first wall portion 211. In short, microwaves generated by the oscillator 1 are supplied to the internal space SP1 through the opening 22 of the first wall portion 211. The opening 22 is, for example, rectangular. However, the opening 22 may also be circular, and its shape is not limited.

[0075] In the microwave heating apparatus 100D of Embodiment 2, the object to be heated TA2 is in the form of a sheet. More specifically, the object to be heated TA2 is a film material containing a solvent. As a specific example, the object to be heated TA2 is a film material, so-called a prepreg, manufactured by impregnating a fibrous substrate such as glass cloth with varnish (a coating made by adding a solvent to a resin composition) and drying it. Alternatively, the object to be heated TA2 may be a film material, i.e., a resin-coated film, manufactured by coating a film-like substrate such as a support (PET film, etc.) with a resin composition containing a solvent. The object to be heated TA2 is conveyed to the resonator 2A by a roll-to-roll method.

[0076] As shown in Figures 9 and 10, the resonator 2A has a slot 23 through which the object to be heated TA2 passes. The object to be heated TA2 is inserted into the slot 23 from an insertion direction (Z-axis direction) perpendicular to a predetermined direction D1 between the first wall portion 211 and the second wall portion 212. The predetermined range is the range between the first position P11 and the second position P12 in the predetermined direction D1. The object to be heated TA2 passes between the first position P11 and the second position P12 in the predetermined direction D1. The predetermined range through which the object to be heated TA2 passes is in the projection region of the slot 23. The resonator 2A is a single-mode slot waveguide type heating furnace. As shown in Figure 10, the slot 23 is a through-hole that penetrates the resonator 2A along the Z-axis direction. The slot 23 is connected to the internal space SP1. In other words, the object to be heated TA2 passes through the internal space SP1 of the resonator 2A along the Z-axis direction. Slot 23 is a rectangular through-hole when viewed from the Z-axis direction. The dimensions of slot 23 in the X-axis and Y-axis directions are larger than the dimensions of the object TA2 to be heated in the X-axis and Y-axis directions.

[0077] The microwaves supplied to the internal space SP1, which form standing waves, heat the object to be heated TA2 inserted into the slot 23. In other words, the microwaves supplied to the internal space SP1, which form standing waves, heat the object to be heated TA2 as it passes through a predetermined range.

[0078] The first separation distance X11 between a predetermined range (or second position P12) in a predetermined direction D1 and the second wall portion 212 is 1 / 4 or more of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band. With this configuration, the object to be heated TA2 can be heated in a range where the variation in the amount of heating by microwaves in the internal space SP1 is small. As a result, the microwave heating device 100D of Embodiment 2 has the advantage of being able to heat the object to be heated TA2 more uniformly using microwaves.

[0079] More specifically, the first separation distance X11 between a predetermined range (or second position P12) in a predetermined direction D1 and the second wall portion 212 satisfies the following equation (4).

[0080] X11 ≥ λf ０ / 4w formula (4)

[0081] Note that in equation (4), "f ０ " is the center frequency of a predetermined frequency band in which the oscillator 1 can change the microwave frequency. Also, in equation (4), "λ" is the center frequency f ０ This is the wavelength of the microwave when [condition]. Also, "w" in equation (4) is the width of a predetermined frequency band in which the oscillator 1 can change the microwave frequency. According to the above configuration, the object to be heated TA2 can be heated more reliably within a range where the variation in the amount of heating by microwaves in the internal space SP1 is small. As a result, the microwave heating device 100D of Embodiment 2 has the advantage that it can heat the object to be heated TA2 more reliably and uniformly using microwaves.

[0082] In the microwave heating apparatus 100D of Embodiment 2, the second separation distance X23 between a predetermined range (or first position P11) in a predetermined direction D1 and the oscillator 1 is 1 / 4 or more of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band.

[0083] More specifically, in the microwave heating apparatus 100D of Embodiment 2, the second separation distance X23 between a predetermined range (first position P11) in a predetermined direction D1 and the oscillator 1 satisfies the following equation (5).

[0084] X23 ≥ λf ０ / 4w formula (5)

[0085] Note that in equation (5), "f ０ " is the center frequency of a predetermined frequency band in which the oscillator 1 can change the microwave frequency. Also, in equation (5), "λ" is the center frequency f ０ This is the wavelength of the microwave when [condition]. Also, "w" in equation (5) is the width of a predetermined frequency band in which the oscillator 1 can change the microwave frequency. With the above configuration, the object to be heated TA2 can be heated more reliably within a range where the variation in the amount of heating by microwaves in the internal space SP1 is small. As a result, the microwave heating device 100D of Embodiment 2 has the advantage that it can heat the object to be heated TA2 more reliably and uniformly using microwaves.

[0086] (2-3) Modifications of Embodiment 2 Embodiment 2 described above is only one of many embodiments of the present disclosure. Embodiment 2 described above can be modified in various ways depending on the design, etc., as long as the objectives of the present disclosure can be achieved. The following modifications may be implemented by combining them as appropriate. Components similar to those in Embodiment 2 described above are denoted by the same reference numerals and their descriptions are omitted.

[0087] (2-3-1) First Modification of Embodiment 2 The microwave heating device 100E of the first modification of Embodiment 2 comprises an oscillator 1, a resonator 2A, a control device 9, and a coupling circuit mechanism 5, as shown in Figure 11. The coupling circuit mechanism 5 is positioned between the oscillator 1 and the resonator 2A and adjusts the coupling strength between the oscillator 1 and the resonator 2A. The coupling circuit mechanism 5 of the first modification of Embodiment 2 has the same configuration as the coupling circuit mechanism 5 of the first modification of Embodiment 1 (see Figure 4), so a detailed explanation is omitted.

[0088] In the first modified microwave heating apparatus 100E, the third separation distance X31 between a predetermined range (or first position P11) in a predetermined direction D1 and the coupling circuit mechanism 5 is 1 / 4 or more of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band.

[0089] More specifically, in the first modified microwave heating apparatus 100E, the third separation distance X31 between a predetermined range (or first position P11) in a predetermined direction D1 and the coupling circuit mechanism 5 satisfies the following equation (6).

[0090] X31 ≥ λf ０ / 4w type (6)

[0091] Note that in equation (6), "f ０ " is the center frequency of a predetermined frequency band in which the oscillator 1 can change the microwave frequency. Also, in equation (6), "λ" is the center frequency f ０ This is the wavelength of the microwave when [condition]. Also, "w" in equation (6) is the width of a predetermined frequency band in which the oscillator 1 can change the microwave frequency.

[0092] In the first modified microwave heating device 100E, the first separation distance X11 between a predetermined range (or second position P12) in a predetermined direction D1 and the second wall portion 212 satisfies the above-described equation (4), similar to the microwave heating device 100D of Embodiment 2. Furthermore, in the first modified microwave heating device 100E of Embodiment 2, the distance between the slot 23 and the second wall portion 212 in a predetermined direction D1 is λf ０ It is 4W or more.

[0093] In the first modified microwave heating device 100E, the transmission efficiency of microwaves from the oscillator 1 to the resonator 2A is optimized, improving the heating efficiency. Therefore, the first modified microwave heating device 100E has the advantage of being able to heat the object to be heated TA2 more uniformly using microwaves while improving heating efficiency.

[0094] (2-3-2) Second Modified Example of Embodiment 2 The microwave heating device 100F of the second modified example of Embodiment 2, as shown in Figure 12, comprises an oscillator 1, a resonator 2A, a control device 9, a coupling circuit mechanism 5, and a matching device 6. The coupling circuit mechanism 5 is positioned between the oscillator 1 and the resonator 2A and adjusts the coupling strength between the oscillator 1 and the resonator 2A. The matching device 6 is positioned between the oscillator 1 and the coupling circuit mechanism 5. The matching device 6 matches the impedance of the oscillator 1 with the impedance of the resonator 2A and the impedance of the coupling circuit mechanism 5.

[0095] In the second modified microwave heating device 100F, the third separation distance X31 between a predetermined range (or first position P11) in a predetermined direction D1 and the coupling circuit mechanism 5 satisfies equation (6) above, similar to the first modified microwave heating device 100E described above. Also, in the second modified microwave heating device 100F, the first separation distance X11 between a predetermined range (or second position P12) in a predetermined direction D1 and the second wall portion 212 satisfies equation (4) above, similar to the microwave heating device 100D of Embodiment 2 described above. Also, in the second modified microwave heating device 100F of Embodiment 2, the distance between the slot 23 and the coupling circuit mechanism 5 in a predetermined direction D1 is λf ０ It is 4W or more.

[0096] In the second modified microwave heating device 100F, the transmission efficiency of microwaves from the oscillator 1 to the resonator 2A is optimized, and the heating efficiency is further improved. Therefore, the second modified microwave heating device 100F has the advantage of being able to heat the object to be heated TA2 more uniformly using microwaves while further improving the heating efficiency.

[0097] (2-3-3) Third Modification of Embodiment 2 The microwave heating device 100G of the third modification of Embodiment 2 includes an oscillator 1, a resonator 2A, a control device 9, and a matching unit 6, as shown in Figure 13. The matching unit 6 matches the impedance of the oscillator 1 with the impedance of the resonator 2A. The matching unit 6 is connected to both the oscillator 1 (or output unit 13) and the opening 22 of the first wall portion 211 of the resonator 2A.

[0098] In the third modified microwave heating apparatus 100G, the third separation distance X32 between a predetermined range (or first position P11) in a predetermined direction D1 and the matching unit 6 is 1 / 4 or more of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band.

[0099] In the third modified microwave heating device 100G, the third separation distance X32 between a predetermined range (or first position P11) in a predetermined direction D1 and the matching device 6 satisfies the following equation (7). Also, in the third modified microwave heating device 100G of Embodiment 2, the distance between the slot 23 and the matching device 6 in a predetermined direction D1 is λf ０ It is 4W or more.

[0100] X32 ≥ λf ０ / 4w type (7)

[0101] Note that in equation (7), "f ０ " is the center frequency of a predetermined frequency band in which the oscillator 1 can change the microwave frequency. Also, in equation (7), "λ" is the center frequency f ０ This is the wavelength of the microwave when [condition]. Also, "w" in equation (7) is the width of a predetermined frequency band in which the oscillator 1 can change the microwave frequency.

[0102] In the third modified microwave heating device 100G, the first separation distance X11 between a predetermined range (or second position P12) in a predetermined direction D1 and the second wall portion 212 satisfies the above-described equation (4), similar to the microwave heating device 100D of Embodiment 2. Furthermore, in the third modified microwave heating device 100G of Embodiment 2, the distance between the slot 23 and the second wall portion 212 in a predetermined direction D1 is λf ０It is 4W or more.

[0103] In the third modified microwave heating device 100G, the transmission efficiency of microwaves from the oscillator 1 to the resonator 2A is optimized, improving the heating efficiency. Therefore, the third modified microwave heating device 100G has the advantage of being able to heat the object to be heated TA2 more uniformly using microwaves while improving heating efficiency.

[0104] (2-3-4) Other Modifications of Embodiment 2 The following lists other modifications of Embodiment 2 described above.

[0105] As shown in Figure 14, the resonator 2B may have a choke structure 29 that suppresses microwave leakage from the slot 23. This configuration increases the amount of microwaves guided through the internal space SP1 of the resonator 2B. Therefore, the microwave heating device 100D equipped with the resonator 2B has the advantage of being able to efficiently heat the object to be heated TA2.

[0106] More specifically, the resonator 2B has two choke structures 29. The two choke structures 29 are mounted in the slot 23. More specifically, one of the two choke structures 29 is mounted on the side of the slot 23 where the object to be heated TA2 is inserted (front side), and the other choke structure 29 is mounted on the side of the slot 23 where the object to be heated TA2 is removed (rear side).

[0107] Each of the two choke structures 29 is a so-called λ / 4 choke structure. Each of the two choke structures 29 may be a multi-stage type with multiple λ / 4 choke structures, or any choke structure known in the field of microwave ovens and other technologies. Furthermore, the two choke structures 29 may have radio wave absorbing material provided at the inlet and outlet of the slot 23, respectively.

[0108] In the above-described embodiment 2, the resonator 2A is rectangular when viewed from the Y-axis direction. However, the resonator 2A may be folded in a zigzag pattern when viewed from the Y-axis direction. In this disclosure, "zigzag pattern" means a shape in which a plurality of straight sections are aligned along the Z-axis direction, and focusing on the first, second, and third straight sections that are aligned continuously, the first ends of the first and second straight sections are connected by a U-shaped bend, and the second ends of the second and third straight sections are connected by a U-shaped bend.

[0109] The microwave heating apparatus 100D according to Embodiment 2, and the microwave heating apparatus according to each modified example of Embodiment 2, may also be used for firing ceramic devices molded into a green sheet shape, or for curing other plastic devices.

[0110] (3) Embodiment 3 (3-1) Overview Next, an overview of the microwave heating apparatus 100H according to Embodiment 3 will be described with reference to Figure 15. Components similar to those in Embodiment 1 and Embodiment 2 are denoted by the same reference numerals and their descriptions are omitted.

[0111] In the microwave heating apparatus 100D of Embodiment 2 (see Figure 9), the oscillator 1 is located on the first wall portion 211 of the resonator 2A. On the other hand, as shown in Figure 15, in the microwave heating apparatus 100H of Embodiment 3, the oscillator 1 is located on the side wall of the resonator 2C so as to be aligned with the resonator 2C in a second direction D2 that intersects (in this case, orthogonal to) the first direction D1, which is a predetermined direction D1.

[0112] The microwave heating device 100H of Embodiment 3 differs from the microwave heating device 100D of Embodiment 2 in the above respects.

[0113] (3-2) Detailed Configuration (3-2-1) Overall Configuration Below, the detailed configuration of the microwave heating apparatus 100H of Embodiment 3 will be described with reference to Figure 15.

[0114] As shown in Figure 15, the microwave heating device 100H comprises an oscillator 1, a resonator 2C, a control device 9, and a waveguide 8.

[0115] (3-2-2) Oscillator The oscillator 1 generates microwaves to heat the object to be heated TA2, and the frequency of the microwaves can be changed within a predetermined frequency band. The oscillator 1 performs a frequency sweep within the predetermined frequency band in response to control by the control device 9. A detailed explanation of the oscillator 1 in Embodiment 3, which is the same as the oscillator 1 in Embodiments 1 and 2, will be omitted below.

[0116] In Embodiment 3, the oscillator 1 is positioned on the side wall of the resonator 2C via a waveguide 8, so as to be aligned with the resonator 2C in a second direction D2 that intersects (in this case, orthogonal to) the first direction D1, which is a predetermined direction D1. Alternatively, the oscillator 1 in Embodiment 3 may be positioned on the side wall of the resonator 2C without the waveguide 8.

[0117] (3-2-3) Resonator The resonator 2C guides (transmits) the microwaves supplied from the oscillator 1. The resonator 2C is a rectangular waveguide with a rectangular cross-sectional shape. The shape of the resonator 2C is not limited and may be a hollow cylindrical, hollow spherical, or other hollow polygonal prism waveguide. In the following description of the resonator 2C of Embodiment 3, a detailed explanation of the configuration similar to that of the resonator 2A of Embodiment 2 will be omitted.

[0118] In the resonator 2C of Embodiment 3, an opening 22A is provided in the side wall. The internal space SP1 is connected to the oscillator 1 via the opening 22A and the waveguide 8. In short, microwaves generated by the oscillator 1 are supplied to the internal space SP1 via the opening 22A and the waveguide 8. The opening 22A is, for example, rectangular. However, the opening 22A may also be circular, and its shape is not limited.

[0119] In the microwave heating device 100H of Embodiment 3, the first separation distance X11 between a predetermined range (or second position P12) in a predetermined direction D1 and the second wall portion 212 is 1 / 4 or more of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band. With this configuration, the object to be heated TA2 can be heated in a range where the variation in the amount of heating by microwaves in the internal space SP1 is small. As a result, the microwave heating device 100H of Embodiment 3 has the advantage of being able to heat the object to be heated TA2 more uniformly using microwaves.

[0120] More specifically, in the microwave heating device 100H of Embodiment 3, the first separation distance X11 between a predetermined range (or second position P12) in a predetermined direction D1 and the second wall portion 212 satisfies the above-described equation (4), similar to the microwave heating device 100D of Embodiment 2. Furthermore, in the microwave heating device 100H of Embodiment 3, the distance between the slot 23 and the second wall portion 212 in a predetermined direction D1 is λf ０ It is 4W or more.

[0121] In the microwave heating apparatus 100H of Embodiment 3, the second separation distance X24 between a predetermined range (or first position P11) in a predetermined direction D1 and the oscillator 1 is 1 / 4 or more of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band. More specifically, the second separation distance X24 is the distance between a predetermined range (or first position P11) in a predetermined direction D1 and the center of the aperture 22A connected to the oscillator 1 in the predetermined direction D1.

[0122] More specifically, in the microwave heating apparatus 100H of Embodiment 3, the second separation distance X24 between a predetermined range (or first position P11) in a predetermined direction D1 and the oscillator 1 satisfies the following equation (8). Also, in the microwave heating apparatus 100H of Embodiment 3, the distance between the slot 23 and the oscillator 1 in a predetermined direction D1 is λf ０ It is 4W or more.

[0123] X²⁴≧λf ０ / 4w type (8)

[0124] Note that in equation (8), "f０ " is the center frequency of a predetermined frequency band in which the oscillator 1 can change the microwave frequency. Also, in equation (8), "λ" is the center frequency f ０ This is the wavelength of the microwave when [condition]. Also, "w" in equation (8) is the width of a predetermined frequency band in which the oscillator 1 can change the microwave frequency. According to the above configuration, the object to be heated TA2 can be heated more reliably within a range where the variation in the amount of heating by microwaves in the internal space SP1 is small. As a result, the microwave heating device 100H of Embodiment 3 has the advantage that it can heat the object to be heated TA2 more reliably and uniformly using microwaves.

[0125] (3-3) Modifications of Embodiment 3 Embodiment 3 described above is merely one of many embodiments of the present disclosure. Embodiment 3 described above can be modified in various ways depending on the design, etc., as long as the objectives of the present disclosure can be achieved. The following modifications may be implemented by combining them as appropriate. Components similar to those in Embodiment 3 described above are denoted by the same reference numerals and their descriptions are omitted.

[0126] (3-3-1) First Modification of Embodiment 3 The microwave heating device 100I of the first modification of Embodiment 3 comprises an oscillator 1, a resonator 2C, a control device 9, a coupling circuit mechanism 5, and a waveguide 8, as shown in Figure 16. The coupling circuit mechanism 5 is positioned between the oscillator 1 and the resonator 2C and adjusts the coupling strength between the oscillator 1 and the resonator 2C. The coupling circuit mechanism 5 of the first modification of Embodiment 3 has the same configuration as the coupling circuit mechanism 5 of the first modification of Embodiment 1, so a detailed explanation is omitted.

[0127] In the first modified microwave heating apparatus 100I, the third separation distance X33 between a predetermined range (or first position P11) in a predetermined direction D1 and the coupling circuit mechanism 5 is 1 / 4 or more of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band. More specifically, the third separation distance X33 is the distance between a predetermined range (or first position P11) in a predetermined direction D1 and the center of the opening 22A connected to the coupling circuit mechanism 5 in the predetermined direction D1.

[0128] More specifically, in the first modified microwave heating apparatus 100I, the third separation distance X33 between a predetermined range (or first position P11) in a predetermined direction D1 and the coupling circuit mechanism 5 satisfies the following equation (9).

[0129] X33 ≥ λf ０ / 4w type (9)

[0130] Note that in equation (9), "f ０ " is the center frequency of a predetermined frequency band in which the oscillator 1 can change the microwave frequency. Also, in equation (9), "λ" is the center frequency f ０ This is the wavelength of the microwave when [condition]. Also, "w" in equation (9) is the width of a predetermined frequency band in which the oscillator 1 can change the microwave frequency.

[0131] In the first modified microwave heating device 100I, the first separation distance X11 between a predetermined range (or second position P12) in a predetermined direction D1 and the second wall portion 212 satisfies the above-described equation (4), similar to the microwave heating device 100D of the third embodiment described above.

[0132] In the first modified microwave heating device 100I, the transmission efficiency of microwaves from the oscillator 1 to the resonator 2C is optimized, improving the heating efficiency. Therefore, the first modified microwave heating device 100I has the advantage of being able to heat the object to be heated TA2 more uniformly using microwaves while improving heating efficiency.

[0133] (3-3-2) Second Modification of Embodiment 3 The microwave heating device 100J of the second modification of Embodiment 3, as shown in Figure 17, comprises an oscillator 1, a resonator 2C, a control device 9, a coupling circuit mechanism 5, a matching device 6, and a waveguide 8. The coupling circuit mechanism 5 is positioned between the oscillator 1 and the resonator 2C and adjusts the coupling strength between the oscillator 1 and the resonator 2C. The matching device 6 is positioned between the oscillator 1 and the coupling circuit mechanism 5. The matching device 6 matches the impedance of the oscillator 1 with the impedance of the resonator 2C and the impedance of the coupling circuit mechanism 5.

[0134] In the second modified microwave heating device 100J, the third separation distance X33 between a predetermined range (or first position P11) in a predetermined direction D1 and the coupling circuit mechanism 5 satisfies equation (9) above, similar to the first modified microwave heating device 100I described above. Also, in the second modified microwave heating device 100J, the first separation distance X11 between a predetermined range (or second position P12) in a predetermined direction D1 and the second wall portion 212 satisfies equation (4) above, similar to the microwave heating device 100H of Embodiment 3 described above. Also, in the second modified microwave heating device 100J of Embodiment 3, the distance between the slot 23 and the coupling circuit mechanism 5 in a predetermined direction D1 is λf ０ / 4W or more. Also, in the microwave heating device 100J of the second modification of Embodiment 3, the distance between the slot 23 and the second wall portion 212 in a predetermined direction D1 is λf ０ It is 4W or more.

[0135] In the second modified microwave heating device 100J, the microwave transmission efficiency from the oscillator 1 to the resonator 2C is optimized, resulting in improved heating efficiency. Therefore, the second modified microwave heating device 100J has the advantage of being able to heat the object to be heated TA2 more uniformly using microwaves while further improving heating efficiency.

[0136] (3-3-3) Third Modification of Embodiment 3 The microwave heating apparatus 100K of the third modification of Embodiment 3 comprises an oscillator 1, a resonator 2C, a control device 9, a matching unit 6, and a waveguide 8, as shown in Figure 18. The matching unit 6 matches the impedance of the oscillator 1 with the impedance of the resonator 2C. The matching unit 6 is connected to both the oscillator 1 (or output unit 13) and the opening 22A of the first wall portion 211 of the resonator 2C.

[0137] In the third modified microwave heating apparatus 100K, the third separation distance X34 between a predetermined range (or first position P11) in a predetermined direction D1 and the matching unit 6 is 1 / 4 or more of the wavelength of the microwave when the microwave frequency is the center frequency of a predetermined frequency band. More specifically, the third separation distance X34 is the distance between a predetermined range (or first position P11) in a predetermined direction D1 and the center of the aperture 22A connected to the matching unit 6 in the predetermined direction D1.

[0138] In the third modified microwave heating device 100K, the third separation distance X34 between a predetermined range (or first position P11) in a predetermined direction D1 and the matching device 6 satisfies the following equation (10). Also, in the third modified microwave heating device 100K of Embodiment 3, the distance between the slot 23 and the matching device 6 in a predetermined direction D1 is λf ０ It is 4W or more.

[0139] X34 ≥ λf ０ / 4w formula (10)

[0140] Note that in equation (10), "f ０ " is the center frequency of a predetermined frequency band in which the oscillator 1 can change the microwave frequency. Also, in equation (10), "λ" is the center frequency f ０ This is the wavelength of the microwave when [condition]. Also, "w" in equation (10) is the width of a predetermined frequency band in which the oscillator 1 can change the microwave frequency.

[0141] In the third modified microwave heating device 100K, the first separation distance X11 between a predetermined range (or second position P12) in a predetermined direction D1 and the second wall portion 212 satisfies the above-described equation (4), similar to the microwave heating device 100H of Embodiment 3 described above. Furthermore, in the third modified microwave heating device 100K of Embodiment 3, the distance between the slot 23 and the second wall portion 212 in a predetermined direction D1 is λf ０ It is 4W or more.

[0142] In the third modified microwave heating device 100K, the transmission efficiency of microwaves from the oscillator 1 to the resonator 2C is optimized, improving the heating efficiency. Therefore, the third modified microwave heating device 100K has the advantage of being able to heat the object to be heated TA2 more uniformly using microwaves while improving heating efficiency.

[0143] The microwave heating apparatus 100H according to Embodiment 3, and the microwave heating apparatus according to each modified example of Embodiment 3, may also be used for firing ceramic devices molded into a green sheet shape, or for curing other plastic devices.

[0144] (Summary) The microwave heating apparatus (100, 100A to 100K) of the first embodiment comprises an oscillator (1) and resonators (2, 2A, 2B, 2C). The oscillator (1) generates microwaves to heat the object to be heated (TA1, TA2), and the frequency of the microwaves can be changed within a predetermined frequency band. The resonators (2, 2A, 2B, 2C) have an internal space (SP1) and two wall portions (21). In the resonators (2, 2A, 2B, 2C), the object to be heated (TA1, TA2) is placed within a predetermined range of the internal space (SP1). Microwaves are supplied to the internal space (SP1). The two wall portions (21) reflect the microwaves to form standing waves in a predetermined direction (D1). The predetermined range is the range between the first position (P11) and the second position (P12) in a predetermined direction. When the wall portion (21) closer to the first position is designated as the first wall portion (211) and the wall portion (21) closer to the second position (P12) is designated as the second wall portion (212), the separation distance (X1, X11), which is at least one of the distance between the first position (P11) and the first wall portion (211) in the predetermined direction (D1) and the distance between the second position (P12) and the second wall portion (212) in the predetermined direction (D1), is at least 1 / 4 of the wavelength of the microwave when the microwave frequency is the center frequency of the predetermined frequency band.

[0145] This embodiment has the advantage of allowing for more uniform heating using microwaves.

[0146] In the microwave heating apparatus of the second embodiment (100, 100A to 100C), in the first embodiment, the separation distance is X1 and the center frequency is f ０ Assuming that the wavelength of the microwave is λ when the microwave frequency is the center frequency, and the width of the predetermined frequency band is w, the separation distance (X1) satisfies the following equation (1).

[0147] X1 ≥ λf ０ / 4w formula (1)

[0148] This embodiment has the advantage of allowing for more reliable and uniform heating using microwaves.

[0149] A microwave heating apparatus (100A, 100B) of a third embodiment further comprises a coupling circuit mechanism (5) positioned between an oscillator (1) and a resonator (2) in the first or second embodiment, which adjusts the coupling strength between the oscillator (1) and the resonator (2). A second separation distance X21 is a distance different from the first separation distance (X1), between a predetermined range in a predetermined direction (D1) and the coupling circuit mechanism (5), and the center frequency is f ０ Assuming that the wavelength of the microwave is λ when the microwave frequency is the center frequency, and the width of the predetermined frequency band is w, the second separation distance (X2) satisfies the following equation (2).

[0150] X21 ≥ λf ０ / 4w formula (2)

[0151] This embodiment has the advantage of being able to heat more uniformly using microwaves while improving heating efficiency.

[0152] The microwave heating apparatus (100B) of the fourth embodiment further comprises a matching unit (6) positioned between the oscillator (1) and the coupling circuit mechanism (5), which matches the impedance of the oscillator (1) with the impedance of the resonator (2) and the impedance of the coupling circuit mechanism (5).

[0153] This embodiment has the advantage of allowing for more uniform heating using microwaves while further improving heating efficiency.

[0154] A microwave heating apparatus (100C) of the fifth embodiment further comprises a matching circuit (6) positioned between an oscillator (1) and a resonator (2) to match the impedance of the oscillator (1) and the impedance of the resonator (2), in the first or second embodiment. A second separation distance X22 is a distance different from the first separation distance (X1), between a predetermined range in a predetermined direction (D1) and the matching circuit (6), and the center frequency is f ０ Assuming that the wavelength of the microwave is λ when the microwave frequency is the center frequency, and the width of the predetermined frequency band is w, the second separation distance (X22) satisfies the following equation (3).

[0155] X²² ≥ λf ０ / 4w formula (3)

[0156] This embodiment has the advantage of being able to heat more uniformly using microwaves while improving heating efficiency.

[0157] In the sixth embodiment of the microwave heating apparatus (100D to 100K), in the first embodiment, the object to be heated (TA2) is in the form of a sheet. The object to be heated (TA2) is inserted between the first wall portion (211) and the second wall portion (212) of the resonator (2A, 2B, 2C) from an insertion direction perpendicular to a predetermined direction (D1), and a slot (23) is formed through which the object to be heated (TA2) passes. The predetermined range is in the projection area of ​​the slot (23).

[0158] This embodiment has the advantage that the sheet-like object to be heated (TA2) can be heated uniformly.

[0159] In the microwave heating apparatus (100D to 100K) of the seventh embodiment, the separation distance is set to X11 and the center frequency is set to f ０ Assuming that the wavelength of the microwave is λ when the microwave frequency is the center frequency, and the width of the predetermined frequency band is w, the separation distance (X11) satisfies the following equation (4).

[0160] X11 ≥ λf ０ / 4w formula (4)

[0161] This embodiment has the advantage of allowing for more reliable and uniform heating using microwaves.

[0162] In the microwave heating apparatus of the eighth embodiment (100D to 100G), in the sixth or seventh embodiment, the oscillator (1) is arranged on the first wall portion (211). A second separation distance, X23, is a distance different from the first separation distance, which is a separation distance, between a predetermined range in a predetermined direction (D1) and the oscillator (1), and the center frequency is f ０ Assuming that the wavelength of the microwave is λ when the microwave frequency is the center frequency, and the width of the predetermined frequency band is w, the second separation distance (X23) satisfies the following equation (5).

[0163] X23 ≥ λf ０ / 4w formula (5)

[0164] This embodiment has the advantage of allowing for more reliable and uniform heating using microwaves.

[0165] The microwave heating apparatus (100E, 100F) of the ninth embodiment further comprises a coupling circuit mechanism (5) positioned between the oscillator (1) and the resonators (2A, 2B) to adjust the coupling strength between the oscillator (1) and the resonators (2A, 2B), as in the eighth embodiment. When the third separation distance between a predetermined range in a predetermined direction (D1) and the coupling circuit mechanism (5) is X31, the third separation distance (X31) satisfies the following equation (6).

[0166] X31 ≥ λf ０ / 4w type (6)

[0167] This embodiment has the advantage of being able to heat more uniformly using microwaves while improving heating efficiency.

[0168] The microwave heating apparatus (100F) of the tenth embodiment further comprises a matching unit (6) positioned between the oscillator (1) and the coupling circuit mechanism (5), which matches the impedance of the oscillator (1) with the impedance of the resonators (2A, 2B) and the impedance of the coupling circuit mechanism (5).

[0169] This embodiment has the advantage of allowing for more uniform heating using microwaves while further improving heating efficiency.

[0170] The microwave heating apparatus (100G) of the eleventh embodiment further comprises a matching circuit (6) positioned between the oscillator (1) and the resonators (2A, 2B) to match the impedance of the oscillator (1) with the impedance of the resonators (2A, 2B), as in the eighth embodiment. When the third separation distance between a predetermined range in a predetermined direction (D1) and the matching circuit (6) is X32, the third separation distance (X32) satisfies the following equation (7).

[0171] X32 ≥ λf ０ / 4w type (7)

[0172] This embodiment has the advantage of being able to heat more uniformly using microwaves while improving heating efficiency.

[0173] In the microwave heating apparatus (100H to 100K) of the twelfth embodiment, in the sixth or seventh embodiment, the oscillator (1) is aligned with the resonator (2C) in a second direction (D2) intersecting the first direction, which is a predetermined direction (D1). The second separation distance between the oscillator (1) and a predetermined range in the first direction (D1) is a distance different from the first separation distance, which is a separation distance, and is defined as X24, with the center frequency being f ０ Assuming that the wavelength of the microwave is λ when the microwave frequency is the center frequency, and the width of the predetermined frequency band is w, the second separation distance (X24) satisfies the following equation (8).

[0174] X²⁴≧λf ０ / 4w type (8)

[0175] This embodiment has the advantage of allowing for more reliable and uniform heating using microwaves.

[0176] The microwave heating apparatus (100I, 100J) of the 13th embodiment further comprises a coupling circuit mechanism (5) positioned between the oscillator (1) and the resonator (2C) in the second direction (D2) to adjust the coupling strength between the oscillator (1) and the resonator (2C), as in the 12th embodiment. When the third separation distance between a predetermined range in the first direction (D1) and the coupling circuit mechanism (5) is X33, the third separation distance (X33) satisfies the following equation (9).

[0177] X33 ≥ λf ０ / 4w type (9)

[0178] This embodiment has the advantage of being able to heat more uniformly using microwaves while improving heating efficiency.

[0179] The microwave heating apparatus (100J) of the 14th embodiment further comprises a matching circuit (6) positioned between the oscillator (1) and the coupling circuit mechanism (5), which matches the impedance of the oscillator (1) with the impedance of the resonator (2C) and the impedance of the coupling circuit mechanism (5).

[0180] This embodiment has the advantage of allowing for more uniform heating using microwaves while further improving heating efficiency.

[0181] The microwave heating apparatus (100K) of the 15th embodiment further comprises, in the 12th embodiment, a matching circuit (6) positioned between the oscillator (1) and the resonator (2C) in the second direction (D2) to match the impedance of the oscillator (1) with the impedance of the resonator (2C). When the third separation distance between a predetermined range in the first direction and the matching circuit (6) is X34, the third separation distance (X34) is positioned to satisfy the following equation (10).

[0182] X34 ≥ λf ０ / 4w formula (10)

[0183] This embodiment has the advantage of being able to heat more uniformly using microwaves while improving heating efficiency.

[0184] 100, 100A~100K Microwave Heating Device 1; Oscillator 2, 2A, 2B, 2C; Resonator 5; Connecting Circuit Mechanism 6; Integrator 21; Wall Part 23; Slot 211; First Wall Part 212; Second Wall Part D1; Determined Direction (First Direction); D2; Second Direction f ０ Center frequency P11 Position 1 P12 Position 2 SP1 Internal space TA1, TA2 Heated object X1, X11 Separation distance (first separation distance) X21, X22, X23, X24 Second separation distance X31, X32, X33, X34 Third separation distance

Claims

1. A microwave heating device comprising: an oscillator that generates microwaves for heating an object to be heated and can change the frequency of the microwaves within a predetermined frequency band; an internal space to which the microwaves are supplied and two wall portions that reflect the microwaves to form standing waves in a predetermined direction, wherein the object to be heated is placed within a predetermined range of the internal space, the predetermined range being the range between a first position and a second position in the predetermined direction, the wall portion closer to the first position being designated as the first wall portion, and the wall portion closer to the second position being designated as the second wall portion, the separation distance which is at least one of the distance between the first position and the first wall portion in the predetermined direction and the distance between the second position and the second wall portion in the predetermined direction is at least 1 / 4 of the wavelength of the microwaves when the frequency of the microwaves is the center frequency of the predetermined frequency band.

2. Let the separation distance be X1, and the center frequency be f ０ Let λ be the wavelength of the microwave when the frequency of the microwave is the center frequency, and let w be the width of the predetermined frequency band, then the separation distance is X1 ≥ λf ０ A microwave heating apparatus according to claim 1, satisfying formula (1) / 4w.

3. The oscillator and the resonator are further provided with a coupling circuit mechanism that is positioned between them to adjust the coupling strength between the oscillator and the resonator, wherein the second separation distance between the predetermined range in the predetermined direction and the coupling circuit mechanism is a distance different from the first separation distance which is the separation distance, and X21 is set to the center frequency f ０ Let λ be the wavelength of the microwave when the frequency of the microwave is the center frequency, and let w be the width of the predetermined frequency band, then the second separation distance is X21 ≥ λf ０ A microwave heating apparatus according to claim 1 or 2, satisfying formula (2) / 4w.

4. The microwave heating apparatus according to claim 3, further comprising a matching circuit disposed between the oscillator and the coupling circuit mechanism for matching the impedance of the oscillator with the impedance of the resonator and the impedance of the coupling circuit mechanism.

5. The oscillator and the resonator are further provided with a matching circuit, which is positioned between them to match the impedance of the oscillator and the impedance of the resonator, and the second separation distance between the predetermined range in the predetermined direction and the matching circuit is a distance different from the first separation distance, which is the separation distance, and the center frequency is f ０ Let λ be the wavelength of the microwave when the frequency of the microwave is the center frequency, and let w be the width of the predetermined frequency band, then the second separation distance is X22 ≥ λf ０ A microwave heating apparatus according to claim 1 or 2, satisfying formula (3) / 4w.

6. The microwave heating apparatus according to claim 1, wherein the object to be heated is in the form of a sheet, and the resonator has a slot formed between the first wall and the second wall through which the object to be heated is inserted from an insertion direction perpendicular to the predetermined direction and through which the object to be heated passes, and the predetermined range is in the projection area of ​​the slot.

7. Let the separation distance be X11, and the center frequency be f ０ Let λ be the wavelength of the microwave when the frequency of the microwave is the center frequency, and let w be the width of the predetermined frequency band, then the separation distance is X11 ≥ λf ０ A microwave heating apparatus according to claim 6, satisfying formula (4) / 4w.

8. The oscillator is disposed on the first wall portion, and a second separation distance between the oscillator and the predetermined range in the predetermined direction, which is different from the first separation distance that is the separation distance, is defined as X23, and the center frequency is f ０ Let the wavelength of the microwave when the frequency of the microwave is the center frequency be λ, and when the width of the predetermined frequency band is w, the second separation distance satisfies X23 ≧ λf ０ / 4w Formula (5) The microwave heating device according to claim 6 or 7.

9. The oscillator and the resonator are further provided with a coupling circuit mechanism that is positioned between them to adjust the coupling strength between the oscillator and the resonator, and when the third separation distance between the predetermined range in the predetermined direction and the coupling circuit mechanism is X31, the third separation distance is X31 ≥ λf ０ A microwave heating apparatus according to claim 8, satisfying formula (6) / 4w.

10. The microwave heating apparatus according to claim 9, further comprising a matching circuit disposed between the oscillator and the coupling circuit mechanism for matching the impedance of the oscillator with the impedance of the resonator and the impedance of the coupling circuit mechanism.

11. The oscillator and the resonator are further provided with a matching circuit, which is positioned between them to match the impedance of the oscillator and the impedance of the resonator, and when the third separation distance between the predetermined range in the predetermined direction and the matching circuit is X32, the third separation distance is X32 ≥ λf ０ A microwave heating apparatus according to claim 8, satisfying formula (7) / 4W.

12. The oscillator is positioned alongside the resonator in a second direction intersecting the first direction, which is the predetermined direction, and the second separation distance between the oscillator and the predetermined range in the first direction is a distance different from the first separation distance, which is the separation distance, and the center frequency is f ０ Let λ be the wavelength of the microwave when the frequency of the microwave is the center frequency, and let w be the width of the predetermined frequency band, then the second separation distance is X24 ≥ λf ０ A microwave heating apparatus according to claim 6 or 7, satisfying formula (8) / 4w.

13. The device further comprises a coupling circuit mechanism positioned between the oscillator and the resonator in the second direction to adjust the coupling strength between the oscillator and the resonator, and when the third separation distance between the predetermined range in the first direction and the coupling circuit mechanism is X33, the third separation distance is X33 ≥ λf ０ A microwave heating apparatus according to claim 12, satisfying formula (9) / 4W.

14. The microwave heating apparatus according to claim 13, further comprising a matching circuit disposed between the oscillator and the coupling circuit mechanism for matching the impedance of the oscillator with the impedance of the resonator and the impedance of the coupling circuit mechanism.

15. The device further comprises a matching circuit positioned between the oscillator and the resonator in the second direction, which matches the impedance of the oscillator with the impedance of the resonator, and when the third separation distance between the predetermined range in the first direction and the matching circuit is X34, the third separation distance is X34 ≥ λf ０ A microwave heating apparatus according to claim 12, satisfying formula (10) / 4w.

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