JPWO2013001787A1 - Microwave heating device - Google Patents

Abstract

In the microwave heating apparatus, the waveguides (104, 204) that transmit microwaves from the microwave generation units (103, 203) and supply the microwaves to the heating chambers (102, 202) are circularly polarized in the heating chamber. A first microwave supply unit (105a, 105b, 106a, 106b, 107a, 107b, 205, 206, 207) for supplying a microwave and a second microwave for supplying a microwave different from the circularly polarized wave into the heating chamber And a microwave supply unit (108, 109, 110, 208, 209, 210).

Description

  The present invention relates to a microwave heating apparatus such as a microwave oven that radiates microwaves to an object to be heated and performs dielectric heating.

  A microwave oven, which is one of typical microwave heating devices, supplies microwaves radiated from a magnetron, which is a microwave generation unit, to the inside of a metal heating chamber via a waveguide. The object to be heated is heated by dielectric heating. Therefore, if the electromagnetic field distribution of the microwave in the heating chamber is not uniform, there is a problem that the object to be heated cannot be heated uniformly.

  As a means for uniformly heating the object to be heated in the heating chamber, a structure for rotating the object to be heated in the heating chamber by rotating a table on which the object to be heated is placed, or in a state where the object to be heated is fixed There is a configuration that rotates an antenna that radiates waves. As described above, the means for uniformly heating the object to be heated uses a certain driving mechanism to heat the object to be heated while changing the direction of the microwave radiated to the object to be heated. The configuration was common.

  Recently, in order to simplify the configuration, there has been a search for a heating means that achieves uniformity without using a drive mechanism, and a method using circularly polarized waves in which the polarization plane of the electric field rotates with time is proposed. . Originally, since dielectric heating is based on the principle of heating an object to be heated having dielectric loss with a microwave electric field, rotation of the electric field is considered to have an effect on uniformity.

  Specific examples of circularly polarized wave generating means include, for example, US Pat. No. 4,301,347 (Patent Document 1), Japanese Patent No. 3510523 (Patent Document 2) and Japanese Patent Laid-Open No. 2005-235572 ( There is a configuration disclosed in Patent Document 3). FIG. 17 is a diagram illustrating a configuration of a waveguide in the microwave heating apparatus disclosed in Patent Document 1. In FIG. FIG. 18 is a diagram illustrating a configuration of a waveguide in the microwave heating device disclosed in Patent Document 2. In FIG. FIG. 19 is a diagram showing the configuration of the microwave heating device and its antenna disclosed in Patent Document 3. As shown in FIG.

  As shown in FIG. 17, Patent Document 1 discloses a system that uses one X-shaped circularly polarized aperture 2 that intersects the tube wall of the waveguide 1. As shown in FIG. 18, Patent Document 2 shows a configuration having two rectangular slit-shaped openings 3 and 4 arranged so that their longitudinal directions intersect on the same surface of the tube wall of the waveguide 1. The two openings 3 and 4 are formed at positions separated from each other to output circularly polarized waves. In addition, as shown in FIG. 19, Patent Document 3 shows an example in which a patch antenna 5 that is rotated by being coupled to the waveguide 1 is provided, and a part of the circumference of the patch antenna 5 is cut out. 6 is shown.

U.S. Pat. No. 4,301,347 Japanese Patent No. 3510523 Japanese Patent Laying-Open No. 2005-235772

  However, the conventional microwave heating devices disclosed in Patent Documents 1 to 3 as described above have a configuration using circularly polarized waves in any case, but are uniform without using a driving mechanism. It is not the structure which can anticipate the effect which can achieve a heating. Any of the microwave heating devices disclosed in Patent Documents 1 to 3 has a synergistic effect between the circularly polarized wave and the drive mechanism, and compared to the conventional configuration using the microwave (linearly polarized wave) and the drive mechanism, This is a configuration that can be made more uniform.

  Specifically, the microwave heating apparatus disclosed in Patent Document 1 (see FIG. 17) has a rotating body called a phase shifter 7 at the terminal portion of the waveguide 1. By rotating, the phase of the microwave being transmitted through the waveguide 1 is changed to form a circularly polarized wave. In Patent Document 2 (see FIG. 18), instead of a conventional waveguide that forms a linearly polarized wave, a micro that uses a waveguide 1 having two openings 3 and 4 each having a pair of rectangular slit shapes. A wave heating device is disclosed. The microwave heating apparatus disclosed in Patent Document 2 is not circular as beautiful as circularly polarized waves formed by intersecting X-shaped openings, but circularly polarized waves. It is the structure which forms a microwave and uses together with a turntable. Patent Document 3 (see FIG. 19) describes a configuration in which, in addition to the turntable 8, the patch antenna 5 is also rotated and used as a stirrer. In any of Patent Documents 1 to 3, it is not described that uniform heating of an object to be heated can be achieved by using only circularly polarized waves without using a drive mechanism. This is because, when a heated object is heated only by circular polarization from a waveguide without using a drive mechanism, linear polarization from a conventional waveguide and a general drive mechanism (for example, turn This is because the uniform heating is inferior to the configuration using a mechanism for rotating the table and a mechanism for rotating the antenna.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a microwave heating apparatus that can uniformly heat an object to be heated without using a drive mechanism while utilizing circularly polarized waves. And

In order to solve the conventional problems, a microwave heating apparatus according to the present invention includes a heating chamber that accommodates an object to be heated, a microwave generation unit that generates a microwave, and a microwave generated from the microwave generation unit. A waveguide that transmits and supplies the microwave to the heating chamber. The waveguide includes a first microwave supply unit that supplies a circularly polarized microwave into the heating chamber, and the first microwave. A second microwave supply unit that supplies a microwave having a heating region different from the circularly polarized wave from the supply unit into the heating chamber.

  The microwave heating apparatus according to the present invention configured as described above supplies the circularly polarized wave into the heating chamber by the first microwave supply unit, and also the first microwave supply unit by the second microwave supply unit. By supplying a microwave having a heating area (radiation direction) different from the circularly polarized wave from the wave supply unit, it becomes possible to interpolate a weak heating area by using only the circularly polarized wave, without using a drive mechanism. Also, the object to be heated can be heated uniformly.

  ADVANTAGE OF THE INVENTION According to this invention, the microwave heating apparatus which can heat a to-be-heated material uniformly can be provided, without using a drive mechanism, utilizing a circularly polarized wave.

It is a perspective view which shows the structure of the microwave oven which is a microwave heating device of Embodiment 1 which concerns on this invention. It is a schematic diagram at the time of seeing the bottom face and waveguide of the heating chamber in the microwave oven of Embodiment 1 which concerns on this invention from the top. It is a schematic diagram at the time of seeing the heating chamber and waveguide in the microwave oven of Embodiment 1 which concerns on this invention from the front. It is a schematic diagram explaining a general waveguide. FIGS. 5A and 5B are diagrams showing simulation results with the end portion of the waveguide as a radiation boundary, FIG. 5A is a plan image of the simulation model, and FIG. 5B is a plane cross section of the electric field strength distribution in the heating chamber. FIG. FIG. 6A is a plan sectional view of the electric field intensity distribution in the heating chamber, and FIG. 6B is an electric field in the heating chamber. It is front sectional drawing of intensity distribution. In the structure of Embodiment 1 which concerns on this invention, it is a schematic diagram at the time of seeing the bottom face and waveguide of a heating chamber in case the auxiliary | assistant microwave supply means is not formed from the top. It is an image figure which shows the flow of the electric conduction current in the H surface of a waveguide. It is a perspective view which shows the structure of the microwave oven which is a microwave heating device of Embodiment 2 which concerns on this invention. It is a schematic diagram at the time of seeing the bottom face and waveguide of the heating chamber in the microwave oven of Embodiment 2 which concerns on this invention from the top. It is a schematic diagram at the time of seeing the heating chamber and waveguide in the microwave oven of Embodiment 3 which concerns on this invention from the front. It is a schematic diagram explaining a general waveguide. It is a figure which shows the simulation result which made the termination | terminus part of the waveguide the radiation | emission boundary, (a) of FIG. 13 is a plane image figure of a simulation model, (b) of FIG. 13 is a plane cross section of electric field strength distribution in a heating chamber FIG. FIGS. 14A and 14B are diagrams showing a simulation result in which the end portion of the waveguide is a reflection boundary, FIG. 14A is a plan sectional view of the electric field intensity distribution in the heating chamber, and FIG. 14B is an electric field in the heating chamber. It is front sectional drawing of intensity distribution. In the structure of Embodiment 1 which concerns on this invention, it is a schematic diagram at the time of seeing the bottom face and waveguide of a heating chamber in case the auxiliary | assistant microwave supply means is not formed from the top. It is an image figure which shows the flow of the electric conduction current in the H surface of a waveguide. It is a figure which shows the structure of the waveguide in the conventional microwave heating apparatus disclosed by patent document 1. FIG. It is a figure which shows the structure of the waveguide in the conventional microwave heating apparatus disclosed by patent document 2. FIG. It is a figure which shows the structure of the conventional microwave heating apparatus disclosed by patent document 3, and its antenna.

A microwave heating apparatus according to a first aspect of the present invention includes a heating chamber that houses an object to be heated, a microwave generation unit that generates a microwave, and a microwave that is transmitted from the microwave generation unit to perform the heating. A waveguide supplied to the chamber, and the waveguide includes a first microwave supply unit that supplies a circularly polarized microwave into the heating chamber, and a circle from the first microwave supply unit. And a second microwave supply unit for supplying a microwave having a heating region different from the polarization into the heating chamber.
The microwave heating device according to the first aspect of the present invention configured as described above supplies circularly polarized waves into the heating chamber by the first microwave supply unit, and the second microwave supply unit allows the first By supplying a microwave having a heating area different from the circularly polarized wave from one microwave supply section, it becomes possible to interpolate a weakly heated area by using only the circularly polarized wave, without using a driving mechanism. In addition, the heating distribution of the object to be heated can be made uniform.

In the microwave heating apparatus according to the second aspect of the present invention, the first microwave supply section in the first aspect is a circularly polarized wave provided on the H surface of the waveguide facing the heating chamber. An opening,
The second microwave supply unit is an opening provided in the waveguide.
The microwave heating apparatus according to the second aspect of the present invention configured as described above can easily radiate circularly polarized microwaves to the heating chamber from the circularly polarized opening provided on the H surface of the waveguide. It becomes the composition. In addition, the microwave heating apparatus according to the second aspect of the present invention can reliably radiate circularly polarized microwaves from the circularly polarized opening to the heating chamber, and can also open the opening of the second microwave supply unit. Therefore, it is possible to make the heating distribution of the object to be heated uniform without using a drive mechanism with an extremely simple configuration.

In the microwave heating apparatus according to the third aspect of the present invention, the second microwave supply section in the second aspect is an H of the waveguide provided with the first microwave supply section. A linearly polarized aperture is provided on the surface and supplies linearly polarized microwaves into the heating chamber.
The microwave heating apparatus according to the third aspect of the present invention configured as described above has a circularly polarized wave and a linearly polarized wave from the circularly polarized wave opening and the linearly polarized wave opening provided on the H surface of the waveguide to the heating chamber. It is easy to radiate the microwave.

In the microwave heating apparatus according to the fourth aspect of the present invention, the second microwave supply unit in the second aspect or the third aspect is an elongated shape in which the width direction of the waveguide is the longitudinal direction. The opening has a shape and is arranged at a substantially central portion in the width direction of the waveguide.
In the microwave heating apparatus according to the fourth aspect of the present invention configured as described above, the opening of the second microwave supply unit has an elongated hole shape elongated in the width direction of the waveguide. Since the tube is disposed at the substantially central portion in the width direction of the tube, current flowing in the tube axis direction (direction including the transmission direction) on the tube wall of the waveguide is hindered, and the opening of the second microwave supply unit An electric field is generated so as to generate a potential difference at the opposite end in the tube axis direction, and microwaves can be strongly emitted in the tube axis direction of the waveguide. As a result, the region that could not be heated only by the first microwave supply unit can be heated by the second microwave supply unit, and the heating distribution of the object to be heated can be made uniform without using a drive mechanism. Can do.

In the microwave heating apparatus according to the fifth aspect of the present invention, the circularly polarized aperture in the second to fourth aspects is disposed at the antinode of the electric field of the standing wave in the waveguide. Thus, the microwave radiation from the circularly polarized aperture has a strong propagation in the width direction of the waveguide and a weak propagation in the tube axis direction of the waveguide.
The microwave heating apparatus according to the fifth aspect of the present invention configured as described above is heated by using the opening of the second microwave supply unit so as to interpolate the microwave radiation from the circularly polarized opening. A heating region can be formed so as to eliminate unevenness, and the heating distribution can be made uniform without using a driving mechanism.

In the microwave heating apparatus according to the sixth aspect of the present invention, the distance in the transmission direction from the center position of the circularly polarized aperture in the second to fifth aspects to the terminal end of the waveguide The circularly polarized aperture is arranged in the antinode of the electric field of the standing wave in the waveguide.
In the microwave heating apparatus according to the sixth aspect of the present invention configured as described above, the propagation in the width direction of the waveguide is strong only by the circularly polarized wave radiated from the circularly polarized aperture, and the direction is in the tube axis direction. However, by using the opening of the second microwave supply section, it becomes possible to interpolate the heating area and eliminate the heating unevenness. The heating distribution of the heated product can be made uniform.

In the microwave heating apparatus according to the seventh aspect of the present invention, the circularly polarized wave opening of the first microwave supply section and the second microwave supply section in the second to sixth aspects. The openings are configured to be arranged at different positions in the tube axis direction of the waveguide.
In the microwave heating apparatus according to the seventh aspect of the present invention configured as described above, the positions of the circularly polarized wave opening of the first microwave supply unit and the opening of the second microwave supply unit may overlap each other. Therefore, the waveguide can be easily realized.

In the microwave heating apparatus according to the eighth aspect of the present invention, at least one opening in the second microwave supply unit according to the second to seventh aspects is arranged in the transmission direction of the waveguide. It is arranged at a substantially end position.
In the microwave heating apparatus of the eighth aspect according to the present invention configured as described above, the opening in the second microwave supply section has a long hole shape elongated in the width direction of the waveguide. The opening does not overlap with the circularly polarized opening and can be easily formed.

In the microwave heating apparatus according to the ninth aspect of the present invention, at least one opening in the second microwave supply part according to the second aspect to the eighth aspect is provided with the first microwave supply part. Between the two circularly polarized apertures.
The microwave heating apparatus according to the ninth aspect of the present invention configured as described above can be easily configured, and uneven heating due to the first microwave supply unit is caused by the second microwave supply unit. Accordingly, the heating distribution of the object to be heated can be made uniform without using a driving mechanism.

In the microwave heating apparatus according to the tenth aspect of the present invention, in the second microwave supply section according to the second aspect or the third aspect, the tube axis direction of the waveguide is the longitudinal direction. The opening has an elongated shape and is disposed at a position outside the central axis extending in the tube axis direction of the waveguide.
In the microwave heating apparatus according to the tenth aspect of the present invention configured as described above, the opening of the second microwave supply unit has an elongated hole shape in the tube axis direction of the waveguide, and Since it is arranged at a position outside the extending central axis, current flowing in the width direction on the tube wall of the waveguide is prevented, and a potential difference is generated at the opposite end portion in the width direction at the opening of the second microwave supply unit. As a result, an electric field is generated so that microwaves can be radiated strongly in the width direction of the waveguide. As a result, the region that could not be heated only by the first microwave supply unit can be heated by the second microwave supply unit, and the heating distribution of the object to be heated can be made uniform without using a drive mechanism. Can do.

According to an eleventh aspect of the microwave heating apparatus of the present invention, in the second aspect, the third aspect, or the tenth aspect, the circularly polarized aperture is an electric field of a standing wave in the waveguide. The microwave radiation from the circularly polarized aperture is weakly propagated in the width direction of the waveguide and strongly propagated in the tube axis direction of the waveguide. .
The microwave heating apparatus according to the eleventh aspect of the present invention configured as described above is heated using the opening of the second microwave supply unit so as to interpolate the microwave radiation from the circularly polarized opening. A heating region can be formed so as to eliminate unevenness, and the heating distribution can be made uniform without using a driving mechanism.

A microwave heating apparatus according to a twelfth aspect of the present invention is the waveguide according to the second aspect, the third aspect, the tenth aspect, or the eleventh aspect, wherein the waveguide is guided from a center position of the circularly polarized aperture. The distance in the transmission direction to the end of the tube is set to be approximately an integral multiple of 1/2 of the tube wavelength, and the circularly polarized aperture is arranged at the node of the standing wave electric field in the waveguide.
In the microwave heating apparatus according to the twelfth aspect of the present invention configured as described above, the propagation in the width direction of the waveguide is weak with only the circularly polarized wave radiated from the circularly polarized aperture, and the tube axis direction However, it is possible to eliminate heating unevenness by interpolating the heating region by using the opening of the second microwave supply unit, and without using a driving mechanism. The heating distribution of the object to be heated can be made uniform.

A microwave heating apparatus according to a thirteenth aspect of the present invention is the tube axis of the waveguide according to the second aspect, the third aspect, the tenth aspect, the eleventh aspect, or the twelfth aspect. In a region on both sides of the H plane with a central axis extending in the direction as a boundary, a circularly polarized wave opening of the first microwave supply unit and an opening of the second microwave supply unit are alternately arranged in one region And the second microwave supply unit and the circular polarization opening of the first microwave supply unit are alternately arranged in the other region, and the circular polarization of the first microwave supply unit The opening and the opening of the second microwave supply unit are arranged in the width direction of the waveguide.
In the microwave heating apparatus according to the thirteenth aspect of the present invention configured as described above, the second microwave supply unit can compensate for heating unevenness caused by the first microwave supply unit, and the drive mechanism can be Even if it is not used, the heating distribution of the object to be heated can be made uniform.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of a microwave heating apparatus according to the invention will be described with reference to the accompanying drawings. In the microwave heating device of the following embodiment, a microwave oven will be described, but the microwave oven is an example, and the present invention is not limited to the microwave oven, and a heating device using dielectric heating, The present invention can be applied to a microwave heating apparatus such as a garbage disposal machine or a semiconductor manufacturing apparatus. Further, the present invention includes appropriately combining arbitrary configurations described in the respective embodiments described below, and the combined configurations exhibit their respective effects. Furthermore, the present invention is not limited to the specific microwave oven configuration described in the following embodiments, and includes a configuration based on the same technical idea.

(Embodiment 1)
1-3 is a figure for demonstrating the microwave oven which is an illustration of the microwave heating device of Embodiment 1 which concerns on this invention. FIG. 1 is a perspective view showing the entire configuration of a microwave oven that is a microwave heating apparatus according to the first embodiment, and FIG. 2 is a top view of the bottom surface of the heating chamber and the waveguide in the microwave oven according to the first embodiment. FIG. 3 is a schematic diagram when the heating chamber and the waveguide in the microwave oven are viewed from the front.

  As shown in FIG. 1, the microwave oven 101 that is the microwave heating apparatus of the first embodiment is provided with a door 113 that is opened and closed in order to put an object to be heated (not shown) in and out of the heating chamber 102. Yes. FIG. 1 shows a state where the door 113 of the microwave oven 101 is opened.

  As shown in FIGS. 1 to 3, a microwave oven 101 that is a typical microwave heating apparatus includes a heating chamber 102 that can store an object to be heated (not shown), and a microwave generator that generates microwaves. , And a waveguide 104 that guides the microwave radiated from the magnetron 103 to the heating chamber 102. The microwave oven 101 includes a first microwave supply unit that is a circularly polarized wave supply unit for propagating circularly polarized waves in the heating chamber 102 using microwaves transmitted through the waveguide 104. A plurality of circularly polarized apertures 105a, 105b, 106a, 106b, 107a, 107b which are X-shaped openings are formed on the H surface of the waveguide 104 (the surface facing the heating chamber 102 in the first embodiment). Yes. Furthermore, in the microwave oven 101, the heating distribution is not uniform only with the circularly polarized aperture. Therefore, in order to further uniform the heating distribution, a part of the microwave in the waveguide 104 is placed in the heating chamber 102. As a second microwave supply section serving as an auxiliary microwave supply means for supplying, a linearly polarized wave opening 108 having a long hole shape on the H surface of the waveguide 104 (the surface facing the heating chamber 102 in the first embodiment). , 109, 110 are formed.

  On the H plane of the waveguide 104, the positions where the circularly polarized wave openings 105a, 105b, 106a, 106b, 107a, 107b are formed are transmitted from the respective center positions to the end portion 111 of the waveguide 104. The distance in the direction is substantially an odd multiple of 1/4 of the guide wavelength λg. Here, the center positions of the circularly polarized apertures 105a, 105b, 106a, 106b, 107a, and 107b indicate the positions of the center of gravity of the plate materials when it is assumed that each aperture shape is formed of a plate material having the same thickness. is there. In addition, the terminator 111 of the waveguide 104 is a guide that is a terminal position in the transmission direction in the transmission space in the waveguide 104, starting from the microwave output position of the magnetron 103 that is a microwave generator. It refers to the inner wall surface of the closed portion of the wave tube 104. In addition, the substantially odd multiple of 1/4 of the in-tube wavelength λg means to include within a range of ± 10% of the numerical value of the odd multiple of 1/4 of the in-tube wavelength λg.

  As shown in FIG. 3, in the microwave heating apparatus of the first embodiment, in the transmission direction from the center position of each circularly polarized aperture 105 a, 105 b closest to the terminal end 111 to the terminal end 111 of the waveguide 104. The distance is λg / 4, and the distance in the transmission direction from the center position of each circularly polarized aperture 106a, 106b to the end portion 111 of the waveguide 104 is 3λg / 4, and each circular polarization farthest from the end portion 11 is. The distance in the transmission direction from the center position of the wave openings 107a and 107b to the terminal end 111 of the waveguide 104 is 5λg / 4.

  Further, the circularly polarized wave openings 105a and 105b, 106a and 106b, 107a and 107b, which are the first microwave supply parts, are guided in the tube axis direction (left and right direction in FIG. 2) on the H plane of the waveguide 104. The wave tube 104 is provided so as to be paired on both sides of the central axis P. Thus, since the circularly polarized wave openings 105a and 105b, 106a and 106b, 107a and 107b are provided on both sides of the central axis P extending in the tube axis direction of the waveguide 104, the central axis of the waveguide 104 is provided. A circularly polarized wave is reliably radiated from the positions on both sides of P to the heating chamber 102.

  The waveguide 104 according to the first embodiment includes a second microwave serving as an auxiliary microwave supplying unit, together with circularly polarized apertures 105a, 105b, 106a, 106b, 107a, and 107b serving as a first microwave supplying unit. Linearly polarized apertures 108, 109, and 110 are formed as supply portions. As shown in FIG. 2, the linearly polarized wave openings 108, 109, and 110 serving as the second microwave supply unit are elongated long holes whose longitudinal direction is the width direction (vertical direction in FIG. 2) of the waveguide 104. And is formed orthogonal to the central axis P of the waveguide 104 extending in the tube axis direction. That is, the center positions (center of gravity positions) of the linearly polarized apertures 108, 109, and 110 are on the center axis P extending in the tube axis direction of the waveguide 104.

  As will be described in detail later, in the first embodiment, the first linearly polarized wave aperture 108 is formed in the vicinity of the terminal end portion 111 on the E plane of the waveguide 104. On the central axis P in the tube axis direction of the waveguide 104, the second linearly polarized aperture 109 is a first circularly polarized aperture pair (105a, 105b) and a second circularly polarized aperture pair (106a, 106b). The third linearly polarized aperture 110 is formed on the central axis P in the tube axis direction of the waveguide 104 with the second circularly polarized aperture pair (106a, 106b) and the third circularly polarized aperture pair ( 107a, 107b).

  Further, in the microwave oven 101 which is the microwave heating apparatus of the first embodiment, as shown in FIG. 1, circularly polarized wave openings 105a, 105b, 106a, 106b, 107a, 107b and linearly polarized wave openings 108, 109, A mounting table 112 for mounting an object to be heated while covering the upper part of 110 is provided in the heating chamber 102. The mounting table 112 in Embodiment 1 is made of a material that easily transmits microwaves, such as glass or ceramic.

  The circularly polarized wave used in the present invention is a technique widely used in the field of mobile communication and satellite communication. As a familiar use example, ETC (Electronic Toll Collection System) “non-stop automatic toll collection system” Or the like. Circular polarization is a microwave in which the plane of polarization of the electric field rotates with respect to the traveling direction of the radio wave, and when the circular polarization is formed, the direction of the electric field continues to change with time, It has the feature that the magnitude of the electric field strength does not change. If this circularly polarized wave is applied to a microwave heating device, it is expected that the object to be heated will be heated evenly, particularly in the circumferential direction of the circularly polarized wave, as compared with the conventional microwave heating by linearly polarized wave. The Circularly polarized waves are classified into two types from the rotation direction: right-handed polarization (CW: clockwise) and left-handed polarization (CCW: counter clockwise), but there is no difference in heating performance.

  In the microwave oven 101 of the first embodiment, X-shaped circularly polarized apertures 105a, 105b, 106a, 106b, 107a, 107b are provided on both sides of the central axis P extending in the tube axis direction on the H plane of the waveguide 104. The circularly polarized apertures 105a, 105b, 106a, 106b, 107a, and 107b are formed to radiate circularly polarized waves into the heating chamber 102. The X-shape of the circularly polarized apertures 105a, 105b, 106a, 106b, 107a, and 107b is configured by two elongated rectangular slits orthogonal to each other at the center point.

  Next, a waveguide as a microwave transmission means will be described with reference to FIG. FIG. 4 is a diagram schematically showing the internal space of the simplest and general waveguide. As shown in FIG. 4, the internal space of the simplest and general waveguide is a rectangular parallelepiped whose cross section perpendicular to the tube axis direction is rectangular (width a × height b) and whose longitudinal direction is the tube axis direction. It consists of

  When the wavelength output from the microwave generator (magnetron 103) is λ (λ = (speed of light) / (oscillation frequency)), the width a of the waveguide is shorter than one wavelength (λ) of the microwave. By setting longer than the wavelength (λ / 2) (λ> a> λ / 2) and setting the height b of the waveguide shorter than half wavelength (λ / 2) (b <λ / 2), Waveguides are known to transmit microwaves in TE10 mode. In the microwave oven, the wavelength λ is about 120 mm. Generally, the width a of the waveguide is in the range of 80 to 100 mm, and the height b is in the range of 15 to 40 mm.

  In the waveguide shown in FIG. 4, the upper and lower surfaces are called H surfaces 114 and 115 in the sense that the magnetic fields are spiraled in parallel, and the left and right surfaces are the E surfaces 116 in the sense that they are parallel to the electric field. , 117.

  In addition, when the microwave (wavelength: λ) from the microwave generation unit is supplied into the waveguide and the wavelength of the microwave transmitted through the waveguide is expressed as λg as the wavelength in the tube (transmission wavelength), The wavelength (transmission wavelength) λg is expressed by the following equation (1).

  As shown in Equation (1), the in-tube wavelength (transmission wavelength) λg varies depending on the width a dimension of the waveguide, but is independent of the height b dimension of the waveguide.

  In the microwave oven according to the first embodiment, which is an example of the microwave heating apparatus of the present invention, the waveguide as the microwave transmission means formed as described above is used to achieve uniform heating in order to achieve uniform heating. It is configured to radiate both a wave and a linearly polarized wave that is a microwave having a heating region (radiation direction) different from the circularly polarized wave.

  Hereinafter, in the microwave oven of Embodiment 1, the structure which radiates | emits both circularly polarized wave and linearly polarized wave is demonstrated in detail.

  As shown in FIG. 2, each of circularly polarized wave openings 105a, 105b, 106a, 106b, 107a, and 107b in the first embodiment is formed on the H surface of waveguide 104, and has two lengths. It has an opening shape formed in an X shape with the holes orthogonal. The circularly polarized apertures 105a, 105b, 106a, 106b, 107a, and 107b are formed so as to face both sides of the central axis P extending in the tube axis direction on the H plane of the waveguide 104. 105a, 106a and 107a are on the back side of the central axis P (upper side in FIG. 2), and the other circularly polarized apertures 105b, 106b and 107b are on the front side of the central axis P (lower side in FIG. 2; door side). is there. As described above, the circularly polarized wave openings 105a, 105b, 106a, 106b, 107a, and 107b are arranged on the H surface of the waveguide 104 so as to be biased to either one from the central axis P extending in the tube axis direction. . By arranging in this way, the circularly polarized apertures 105a, 105b, 106a, 106b, 107a, and 107b have a shape capable of generating circularly polarized waves. Or left-handed polarized waves.

  However, even if only the aforementioned circularly polarized wave forming means is applied to an actual microwave oven, it cannot be heated uniformly by itself, and eventually a drive mechanism such as a drive unit for stirring the heating chamber is required. Become. As described above, when the circularly polarized wave forming means is applied to the microwave oven, there is a problem that uniform heating of the object to be heated cannot be achieved unless some further contrivance is made.

  When this cause is analyzed, it is considered that the influence of standing waves is large. First, the major difference between an ETC and a microwave oven is whether it radiates in an open space (ETC) or in a closed space (microwave oven). Since the microwave oven is used with the door 113 closed, the space covered by the microwave is a closed space, and the microwave is repeatedly reflected in the heating chamber and the waveguide, and as a result, a space where a standing wave is likely to be generated. Due to the influence of the standing wave generated in this closed space, it is considered that even the circularly polarized wave cannot be heated uniformly. In this regard, in the configuration of the first embodiment, certain knowledge has been obtained by simulation, which will be described below.

  5 to 7 are diagrams showing simulation results for clarifying the influence of the standing wave in the waveguide 102. FIG. In these simulations, the wall surface of the heating chamber 102 is set as a radiation boundary (boundary condition in which microwaves do not reflect), and the X-shaped circularly polarized aperture 118 has only one configuration. The condition of the end portion 119 (open or closed) is used as a parameter.

  FIG. 5 shows a simulation result when the end portion 119 of the waveguide 104a is opened to be a radiation boundary (a boundary condition in which the microwave is not reflected). FIG. 5A is a plan image diagram of a simulation model when a simulation is performed, and shows a simulation model shape when the heating chamber 102 is viewed from above. In FIG. 5A, the image when the simulation is performed is described as it is, and it is assumed that the potato Q is arranged as a heated object in the center of the heating chamber 102. FIG. 5B is an analysis result, and is a contour diagram of a plane cross section showing the electric field strength distribution in the heating chamber 102 as viewed from above. As shown in FIG. 5B, in the heating chamber 102, the electric field is swirled like a circularly polarized wave, the tube axis direction X of the waveguide 104a (the left-right direction in FIG. 5B), and The electric field distribution is also uniform in the width direction Y of the waveguide 104a (the vertical direction in FIG. 5B).

  FIG. 6 shows a case where the end portion 128 of the waveguide 104b is closed to form a reflection boundary (a boundary condition in which microwaves are reflected), and an X-shaped circularly polarized aperture 118 is defined in the waveguide 104b. The position of the end portion 128 is determined so as to be the position of the “antinode” of the standing wave. FIG. 6A is a contour diagram of a planar cross section showing the electric field strength distribution in the heating chamber 102 as viewed from above. FIG. 6B is a contour diagram of the electric field strength distribution of the cross section when the heating chamber 102 is viewed from the front.

  As shown in FIG. 6A, the electric field in the tube axis direction X of the waveguide 104b (the left-right direction in FIG. 6A) is weak, and there is not much microwave in the tube axis direction X from the circularly polarized aperture 118. Not propagated. On the other hand, the electric field in the width direction Y (the vertical direction in FIG. 6A) of the waveguide 104b is strong, and microwaves are propagated widely from the circularly polarized aperture 118 in the width direction.

  As shown in FIG. 6B, the strength of the electric field appears in the waveguide 104b below the heating chamber 102, and it is clear that a standing wave is generated. 6B, reference numerals 129, 130, and 131 in the waveguide 104b indicate “antinodes” of the standing wave, and reference numerals 132 and 133 indicate “nodes” of the standing wave. In particular, as shown in FIG. 6B, the formation position of the circularly polarized wave opening 118 is the position of the “antinode” 130 of the standing wave. In this simulation, the distance in the transmission direction from the center position (center of gravity position) of the circularly polarized aperture 118 to the end portion 128 is set to be 3/4 of the guide wavelength λg, and the standing wave is almost in the guide. It occurs in accordance with 1/2 of the wavelength λg.

  Based on the above, as a new finding, when a standing wave is generated in the waveguide, the circularly polarized wave radiated from the circularly polarized opening to the heating chamber is destroyed by the standing wave, and in particular, the circularly polarized opening is fixed. When located at the “antinode” of the standing wave, it was discovered that the microwave propagates strongly in the width direction of the waveguide and weakly propagates in the tube axis direction.

  Therefore, if the direction in which the propagation is weakened when the circularly polarized wave breaks can be predicted in advance, the heating distribution can be made uniform if it is configured to supplementarily supply the microwave. It was thought that there was no chance to recall the configuration of the first embodiment of the present invention.

  FIG. 7 shows a configuration that was studied before the configuration of the first embodiment according to the present invention was conceived. FIG. 7 shows an example in which only the X-shaped circularly polarized apertures 105a, 105b, 106a, 106b, 107a, and 107b are formed on the H surface of the waveguide 104c. It is a schematic diagram at the time of seeing from.

  Compared with the configuration of the first embodiment shown in FIG. 2 described above, the configuration shown in FIG. 7 has linearly polarized apertures 108, 109, and 110 serving as a second microwave supply unit serving as auxiliary microwave supply means. The configuration is not formed.

  Before conceiving the configuration of the first embodiment according to the present invention, the present inventor believes that if a plurality of circularly polarized apertures are arranged in parallel in the waveguide 104c, the heating distribution becomes uniform. Thus, the arrangement shown in FIG. 7 was tried. However, in the arrangement shown in FIG. 7, the area A indicated by hatching in FIG. 7 is heated strongly, and the heating area spreads to some extent in the width direction of the waveguide 104c, but is heated in the tube axis direction. Unevenness occurred, and the heating distribution was not uniform.

  As shown in FIG. 7, the microwave is brought into the heating chamber 102 by the first pair of circularly polarized apertures (105 a and 105 b) configured by two circularly polarized apertures 105 a and 105 b arranged in parallel in the width direction. A heating area A that propagates and extends in the width direction is formed. Similarly, the microwave propagates into the heating chamber 102 and spreads in the width direction by the second circularly polarized aperture pair (106a, 106b) and the third circularly polarized aperture pair (107a, 107b). Is formed. Accordingly, the heating region A by the first circularly polarized aperture pair (105a, 105b), the heated region A by the second circularly polarized aperture pair (106a, 106b), and the third circularly polarized aperture pair (107a, In the heating area A according to 107b), microwaves are radiated strongly, but there are areas where microwaves are not radiated so much between the areas, and the heating distribution in the heating chamber is not uniform. It was. Further, in the heating chamber 102, the region between the side wall (the left side wall in FIG. 7) near the terminal end 111c of the waveguide 104 and the heating region A by the first circularly polarized aperture pair (105a, 105b). There was also a region where microwaves were not emitted very much.

  When the distance in the tube axis direction from the terminal end portion 111c of the waveguide 104c at this time to the center position (center of gravity position) of each circularly polarized aperture 105a, 105b, 106a, 106b, 107a, 107b is examined in detail, The distance was either λg / 4, 3λg / 4, or 5λg / 4. In other words, the center positions (center of gravity positions) of all the circularly polarized apertures 105a, 105b, 106a, 106b, 107a, 107b were arranged at the position of the “antinode” of the standing wave generated in the waveguide 104c. . Therefore, each of the six circularly polarized apertures 105a, 105b, 106a, 106b, 107a, and 107b is positioned at the “antinode” of the standing wave in the waveguide 104c, as shown in FIG. Therefore, any of the circularly polarized apertures 105a, 105b, 106a, 106b, 107a, 107b is considered to be in a state close to the contour diagram shown in FIG.

  The microwave oven according to Embodiment 1 of the present invention is configured as shown in FIG. 2 described above, and is a configuration in which the problem in the configuration shown in FIG. 7 is solved. As described above, in the configuration shown in FIG. 7, the propagation of the microwave radiated from the circularly polarized apertures 105a, 105b, 106a, 106b, 107a, 107b into the heating chamber 102 is in the width direction of the waveguide 104c. And weak in the tube axis direction of the waveguide 104c. Therefore, as shown in FIG. 2, the waveguide 104 according to the first embodiment has a linearly polarized wave aperture 108 as a second microwave supply unit that is an auxiliary microwave supply unit that radiates linearly polarized waves. 109, 110 are formed. This is because the long-hole-shaped linearly polarized apertures 108, 109, 110 are formed on the H-plane of the waveguide 104, and the microwaves from these linearly polarized apertures 108, 109, 110 are guided into the waveguide 104. It is considered that the heating chamber is made uniform by propagating in the tube axis direction.

  In the microwave oven according to the first embodiment, as shown in FIG. 2, the linearly polarized wave openings 108, 109, and 110 serving as the second microwave supply unit have a long hole shape elongated in the width direction of the waveguide 104. . The center position (center of gravity position) of each linearly polarized wave aperture 108, 109, 110 is arranged on the center axis P extending in the tube axis direction of the waveguide 104. In the first embodiment, the first linearly polarized aperture 108 is formed in the vicinity of the terminal end portion 111 on the H plane of the waveguide 104. The second linearly polarized wave aperture 109 is a first circularly polarized aperture pair (105a, 105b) configured by circularly polarized apertures 105a, 105b arranged in parallel in the width direction on the H plane of the waveguide 104. And a second circularly polarized aperture pair (106a, 106b) formed by circularly polarized apertures 106a, 106b arranged in parallel in the width direction. Similarly, the third linearly polarized aperture 110 is a second circularly polarized aperture pair (106a) formed by circularly polarized apertures 106a and 106b arranged in parallel in the width direction on the H plane of the waveguide 104. , 106b) and a third pair of circularly polarized apertures (107a, 107b) formed by circularly polarized apertures 107a, 107b arranged in parallel in the width direction.

  The microwave oven according to the first embodiment configured as described above is guided in the width direction by the waveguide 104 by the circularly polarized wave openings 105a, 105b, 106a, 106b, 107a, 107b as the first microwave supply unit. In addition to the heating area A that expands, the heating area B that extends in the tube axis direction can be combined and heated by the linearly polarized wave openings 108, 109, and 110 that are the second microwave supply units.

  As a result, the region of the side wall (left side wall in FIG. 2) that is in the vicinity of the terminal end 111 in the transmission direction of the waveguide 104 in the heating chamber 102 and the first circularly polarized aperture pair (105a, 105b) A heating region B extending in the tube axis direction is formed by the first linearly polarized aperture 108 in a region between the heating region A extending in the width direction formed by the propagation of the wave. Further, the heating region A that is formed by propagation of microwaves by the first circularly polarized aperture pair (105a, 105b) and that extends in the width direction and the second circularly polarized aperture pair (106a, 106b) is microwaves. A heating region B extending in the tube axis direction is formed by the second linearly polarized wave aperture 109 in a region between the heating region A extending in the width direction formed by the propagation of. Similarly, a heating area A that is formed by propagation of microwaves by the second circularly polarized aperture pair (106a, 106b) and that extends in the width direction and a third circularly polarized aperture pair (107a, 107b) is microscopic. A heating area B extending in the tube axis direction is formed by the third linearly polarized wave opening 110 in a region between the heating area A extending in the width direction formed by the propagation of the wave. Therefore, the microwave oven according to Embodiment 1 has a configuration in which an object to be heated disposed in the heating chamber 102 can be uniformly heated.

  Hereinafter, a method of setting the formation positions of the linearly polarized wave apertures 108, 109, and 110 as the second microwave supply unit as the auxiliary microwave supply unit in the configuration of the first embodiment will be described.

  FIG. 8 is a plan view showing an H-plane 137 on the tube wall of a general TE10 mode waveguide 136. FIG. 8 shows the direction in which the conduction current flows in the H plane 137 at a certain moment, and shows that there are a spring point 138 and a suction point 139 in the center in the width direction. Assuming that the microwave is transmitted from the left to the right in FIG. 8 as indicated by the arrow Z, the spring point 138 and the suction point 139 are also sequentially moved to the right. However, the spring point 138 and the suction point 139 on the tube wall always occur at the center position in the width direction of the waveguide 136. However, in the waveguide 136, the conduction current that flows simultaneously with the conduction current flowing between the spring point 138 and the suction point 139 is not limited to the current flowing between the spring point 138 and the suction point 139. The electric current 141 flows from the point 138 to the suction point (not shown) of the H surface on the opposite back surface through the E surface (not shown), or conversely, the opposite H surface of the opposite surface side. There is a current 142 or the like in which a conduction current from a spring point (not shown) flows into the suction point 139 through the E plane (not shown). Therefore, by arranging the opening at an appropriate position in consideration of the direction of these currents, the direction of the microwave radiated from the opening can be freely set to the tube axis direction of the waveguide or the width direction of the waveguide. It becomes possible to select.

  For example, the elongated rectangular oblong opening 143 shown in FIG. 8 whose longitudinal direction is the width direction prevents the current 144 flowing from the spring point 138 in the right direction (transmission direction). An electric field is generated so as to generate a potential difference at both ends (opposite ends in the tube axis direction) of the side, and microwaves can be strongly emitted in the left-right direction in FIG. 8, that is, the tube axis direction of the waveguide 136. Become. The spring point 138 and the suction point 139 move to the right (in the direction of arrow Z in FIG. 8) as time elapses, and such a long hole-shaped opening 143 has a current in a direction perpendicular to the opening 143. As a result, the current in the left-right direction is always prevented. As a result, an electric field is generated in the opening 143 so that a potential difference is generated at both left and right ends (opposite ends in the tube axis direction) of FIG. 8, and in the left and right direction of FIG. Microwaves will be emitted strongly.

  Note that the elongated rectangular long hole-shaped opening 145 whose longitudinal direction is the tube axis direction shown in FIG. 8 prevents the current 142 flowing from the E surface to the H surface, so both end portions of the opening 145 on the upper and lower sides in FIG. An electric field is generated so as to generate a potential difference at the (opposite end portion in the width direction), and microwaves can be strongly emitted in the vertical direction in FIG. 8, that is, in the width direction of the waveguide 136. The spring point and the suction point move to the right (in the direction of arrow Z in FIG. 8) as time passes, but such a long hole-shaped opening 145 prevents current in a direction perpendicular to the opening 145. Eventually, the current in the vertical direction will always be hindered. As a result, an electric field is generated at both ends of the opening 145 on the upper and lower sides in FIG. 8 (opposing ends in the width direction) so as to generate a potential difference, and microwaves are formed in the vertical direction in FIG. Will be emitted strongly.

  Therefore, in the microwave oven of the first embodiment, as the auxiliary microwave supply means (second microwave supply unit), the linearly polarized apertures 108, 109, and 110 are formed on the H surface of the waveguide 104, as shown in FIG. As shown in the figure, it is a long hole shape elongated in the width direction of the waveguide 104, and is disposed at a substantially central portion in the width direction of the waveguide 104. By forming the linearly polarized wave openings 108, 109, and 110 in this way, the current in the left-right direction in FIG. 2 is hindered, as with the opening 143 shown in FIG. As a result, an electric field is generated so that a potential difference is generated between the left and right ends of the linearly polarized wave apertures 108, 109, and 110 (opposite ends in the tube axis direction) in FIG. The configuration is such that microwaves are strongly emitted in the direction of the tube axis 104. In FIG. 2, hatching regions B are described on the left and right sides of the linearly polarized apertures 108, 109, and 110, and regions where microwaves are strongly emitted are schematically shown.

  As described above, the microwave oven 101 that is the microwave heating apparatus according to the first embodiment of the present invention includes the heating chamber 102 that stores an object to be heated, and the magnetron 103 that is a microwave generation unit that generates a microwave. , And a waveguide 104 that transmits and supplies the microwave from the magnetron 103 to the heating chamber 102. The waveguide 104 has a circular shape that generates a circularly polarized wave in the heating chamber 102 using the microwave. A microwave having a heating region (radiation direction) different from the circularly polarized wave from the circularly polarized wave supplying means for uniforming the heating distribution and the polarized wave supplying means (first microwave supplying unit) is heated in the heating chamber 102. Auxiliary microwave supply means (second microwave supply unit) for supplying the inside.

  In the microwave heating apparatus (microwave oven 101) according to Embodiment 1 configured as described above, in addition to supplying circularly polarized waves into the heating chamber by the circularly polarized wave supplying means, the auxiliary microwave supplying means also By supplying a microwave having a heating area different from the circularly polarized wave from the circularly polarized wave supplying means, it becomes possible to assist the heating area of the weak part only with the circularly polarized wave, without using a drive mechanism, In this configuration, the heating distribution of the object to be heated can be made uniform.

  In the microwave heating apparatus of the first embodiment, the waveguide 104 that guides the microwave from the microwave generation unit to the heating chamber 102 is guided as a circularly polarized wave supply unit (first microwave supply unit). An X-shaped circularly polarized aperture 105a, 105b, 106a, 106b, 107a, 107b provided on the H surface of the tube 104, and an H of the waveguide 104 as auxiliary microwave supply means (second microwave supply unit). Long hole-shaped linearly polarized wave openings 108, 109, and 110 are formed on the surface.

  In the waveguide 104 configured as described above, it is easy to radiate microwaves to the heating chamber 102 from the opening formed in the H surface which is the surface facing the heating chamber 102, and the circularly polarized wave In addition to being able to radiate circularly polarized waves from the supplying means (circularly polarized apertures 105a, 105b, 106a, 106b, 107a, 107b) to the heating chamber 102, auxiliary microwave supplying means (linearly polarized apertures) 108, 109, and 110) can supplementarily supply microwaves having a heating region different from the circularly polarized wave from the circularly polarized wave supplying means into the heating chamber 102, so that the drive mechanism is not used with a very simple configuration. The heating distribution of the object to be heated can be made uniform.

  In the microwave heating apparatus according to the first embodiment, the microwave radiated into the heating chamber 102 from the circularly polarized apertures 105a, 105b, 106a, 106b, 107a, and 107b serving as the circularly polarized wave supplying means has a width of Propagation in the direction is strong, and propagation in the tube axis direction tends to be weak. For this reason, the microwave heating apparatus of the first embodiment is provided with linearly polarized apertures 108, 109, and 110 serving as auxiliary microwave supply means. In order to strongly propagate the microwaves from the linearly polarized apertures 108, 109, and 110 in the tube axis direction, the linearly polarized apertures 108, 109, and 110 are arranged in the width direction of the waveguide 104 as shown in FIG. It has an elongated long hole shape and is arranged at a substantially central portion in the width direction.

  As described above, in the microwave heating apparatus according to the first embodiment, the linearly polarized apertures 108, 109, and 110 are formed in a long and narrow shape in the width direction of the waveguide 104, and are disposed at a substantially central portion in the width direction. As a result, like the opening 143 shown in FIG. 8, the linearly polarized wave openings 108, 109, and 110 prevent the current flowing in the left-right direction in FIG. 2. As a result, an electric field is generated so that a potential difference is generated between the left and right ends (opposite ends in the tube axis direction) of FIG. 2 in the linearly polarized apertures 108, 109, and 110, and the horizontal direction of FIG. The configuration is such that microwaves can be radiated strongly in the direction of the tube axis 104. Therefore, the microwave heating apparatus of the first embodiment can heat the hatched portion B (see FIGS. 2 and 8) that could not be heated only by the circularly polarized wave supply means (first microwave supply unit). Thus, the heating distribution of the object to be heated can be made uniform without using a driving mechanism.

  In the microwave heating apparatus of the first embodiment, circularly polarized apertures 105 a, 105 b, 106 a, 106 b, 107 a, and 107 b are arranged at the “antinode” position of the standing wave electric field in waveguide 104. The state where the propagation in the width direction of the waveguide 104 is strong and the propagation in the tube axis direction is weak can easily occur. However, as described above, the linearly polarized wave openings 108, 109, and 110 serving as auxiliary microwave supply means (second microwave supply unit) are formed in an elongated hole shape in the width direction of the waveguide 104, and By disposing at the substantially central portion in the width direction, the propagation in the tube axis direction of the waveguide 104 is strengthened, and the heating region can be reliably compensated to prevent heating unevenness, and the drive mechanism is Even if it is not used, the heating distribution of the object to be heated can be made uniform.

  The microwave heating apparatus according to the first embodiment determines the distance in the transmission direction from the center position (center of gravity position) of each circularly polarized aperture 105a, 105b, 106a, 106b, 107a, 107b to the end portion 111 of the waveguide 104. , Approximately odd multiple of ¼ of the guide wavelength λg. Thus, by determining the position of each circularly polarized aperture 105a, 105b, 106a, 106b, 107a, 107b, each circularly polarized aperture 105a, 105b, 106a, 106b, 107a, 107b is actually guided. The configuration is located at the “antinode” of the electric field of the standing wave in the tube 104. As a result, as described above, only the circularly polarized apertures 105a, 105b, 106a, 106b, 107a, and 107b have a strong propagation in the width direction of the waveguide 104 and a weak propagation in the tube axis direction. Will get. However, in the microwave heating apparatus of the first embodiment, as the auxiliary microwave supply means (second microwave supply unit), the linearly polarized apertures 108, 109, and 110 are guided on the H surface of the waveguide 104. By forming the tube 104 in the shape of an elongated hole in the width direction and disposing it at a substantially central portion in the width direction, the heating area can be reliably compensated to prevent heating unevenness, and there is no drive mechanism. Also, the heating distribution of the object to be heated can be made uniform.

  In the microwave heating apparatus of the first embodiment, circularly polarized wave supplying means (circularly polarized wave openings 105a, 105b, 106a, 106b, 107a, 107b) and auxiliary microwave supplying means (linearly polarized wave openings 108, 109, 110) Are arranged at different positions that do not overlap each other in the tube axis direction of the waveguide (the direction including the transmission direction). For this reason, the microwave heating apparatus according to the first embodiment can easily realize a desired waveguide by reliably arranging the circularly polarized wave supplying means and the auxiliary microwave supplying means in the waveguide.

  In particular, the first linearly polarized aperture 108 is configured to be disposed at the end portion in the transmission direction on the H-plane of the waveguide 104 and has a long hole shape elongated in the width direction of the waveguide 104. It can be easily formed without overlapping the circularly polarized wave openings 105a and 105b closest to the end portion in the transmission direction at 104.

  Regarding the other linearly polarized apertures 109 and 110, the region between the circularly polarized apertures in the tube axis direction, that is, the first circularly polarized aperture pair (105a, 105b) and the second circularly polarized aperture. It arrange | positions in the area | region between aperture pair (106a, 106b) and the area | region between 2nd circularly polarized aperture pair (106a, 106b) and 3rd circularly polarized aperture pair (107a, 107b). Since it is configured, it can be easily formed.

  In the configuration of the first embodiment, six circularly polarized wave apertures 105a, 105b, 106a, 106b, 107a, and 107b as circularly polarized wave supplying means, and three linearly polarized wave apertures as auxiliary microwave supplying means. Although description has been made using a configuration example provided with 108, 109, and 110, in the present invention, the number of circularly polarized wave supplying means and auxiliary microwave supplying means is not limited to such a number.

  As described above, the microwave heating apparatus according to the first embodiment of the present invention is provided with the circularly polarized wave supplying unit and the auxiliary microwave supplying unit, thereby heating the circularly polarized wave from the circularly polarized wave supplying unit. Since the region difficult to heat by the circularly polarized wave can be heated by the microwave having a heating region different from the circularly polarized wave, the object to be heated arranged in the heating chamber is uniform without using a driving mechanism. It becomes the structure which can be heated to.

(Embodiment 2)
9-11 is a figure for demonstrating the microwave oven which is an illustration of the microwave heating device of Embodiment 2 which concerns on this invention. FIG. 9 is a perspective view showing the entire configuration of the microwave oven that is the microwave heating apparatus of the second embodiment. FIG. 10 is a top view of the bottom surface of the heating chamber and the waveguide in the microwave oven of the second embodiment. FIG. 11 is a schematic diagram when the heating chamber and the waveguide in the microwave oven are viewed from the front.

  As shown in FIG. 9, the microwave oven 201 which is the microwave heating apparatus of the second embodiment is provided with a door 213 for taking an object to be heated (not shown) into and out of the heating chamber 202. FIG. 9 shows a state where the door 213 of the microwave oven 201 is opened.

  As shown in FIGS. 9 to 11, a microwave oven 201 that is a typical microwave heating apparatus includes a heating chamber 202 that can store an object to be heated (not shown), and a microwave generator that generates microwaves. And a waveguide 204 that guides the microwave radiated from the magnetron 203 to the heating chamber 202. In addition, the microwave oven 201 has a first microwave supply unit which is a circularly polarized wave supply unit for propagating circularly polarized waves in the heating chamber 202 using microwaves transmitted in the waveguide 204. A plurality of circularly polarized apertures 205, 206, and 207, which are X-shaped apertures, are formed on the H surface of the waveguide 204 (the surface facing the heating chamber 202 in the second embodiment). Furthermore, in the microwave oven 201, the heating distribution is not uniform only by the circularly polarized aperture. Therefore, in order to further uniform the heating distribution, a part of the microwave in the waveguide 204 is placed in the heating chamber 202. As a second microwave supply unit serving as an auxiliary microwave supply unit to supply, a linearly polarized wave opening 208 having a long hole shape on the H surface of the waveguide 204 (the surface facing the heating chamber 202 in the second embodiment). , 209, 210 are formed.

  On the H plane of the waveguide 204, the positions where the circularly polarized apertures 205, 206, and 207 are formed are the distances in the transmission direction from the respective center positions to the terminal end 211 of the waveguide 204. It is a substantially integer multiple of 1/2 of the wavelength λg. Here, the center position of the circularly polarized apertures 205, 206, and 207 indicates the position of the center of gravity of the plate material when it is assumed that each aperture shape is formed of a plate material having the same thickness. In addition, the terminal end 211 of the waveguide 204 is a guide that is the end position in the transmission direction in the transmission space in the waveguide 204, with the microwave output position of the magnetron 203 serving as the microwave generating unit as the start end. It refers to the inner wall surface of the closed portion of the wave tube 204. The term “substantially an integral multiple of ½ of the in-tube wavelength λg” means to include within a range of ± 10% of a value that is an integral multiple of ½ of the in-tube wavelength λg.

  As shown in FIG. 11, in the microwave heating apparatus of the second embodiment, the distance in the transmission direction from the center position of the circularly polarized opening 205 closest to the terminal end 211 to the terminal end 211 of the waveguide 204 is λg. / 2, and the distance in the transmission direction from the center position of the circularly polarized aperture 206 to the end portion 211 of the waveguide 204 is λg, and is guided from the center position of the circularly polarized aperture 207 farthest from the end portion 211. The distance in the transmission direction to the end portion 211 of the tube 204 is 3λg / 2.

  Further, the circularly polarized wave openings 205, 206, and 207, which are the first microwave supply portions, are center axes of the waveguide 204 that extends in the tube axis direction (left-right direction in FIG. 10) on the H plane of the waveguide 204. It is provided on both sides of P. As described above, since the circularly polarized wave openings 205, 206, and 207 are provided on both sides of the central axis P extending in the tube axis direction of the waveguide 204, the circularly polarized wave openings 205, 206, and 207 are located from both sides of the central axis P of the waveguide 104. The configuration is such that circularly polarized waves are reliably radiated to the heating chamber 102.

  The waveguide 204 according to the second embodiment has a linearly polarized wave that is a second microwave supply unit serving as an auxiliary microwave supply unit, as well as circularly polarized apertures 205, 206, and 207 that are first microwave supply units. Wave openings 208, 209, and 210 are formed. As shown in FIG. 10, the linearly polarized wave openings 208, 209, and 210 serving as the second microwave supply unit have a long hole shape in which the tube axis direction of the waveguide 204 (the horizontal direction in FIG. 10) is the longitudinal direction. And formed in parallel on both sides of the central axis P extending in the tube axis direction of the waveguide 204. In the configuration of the second embodiment, as shown in FIG. 10, in the regions on both sides of the center axis P on the H plane, the opening (206) of the first microwave supply unit and the second The openings (208, 210) of the microwave supply unit are alternately arranged, and the opening (205, 207) of the first microwave supply unit and the opening (209) of the second microwave supply unit are arranged in the other region. It is the structure arrange | positioned alternately.

  Moreover, in the microwave oven 201 which is the microwave heating apparatus of the second embodiment, as shown in FIG. 9, while covering the upper portions of the circularly polarized apertures 205, 206, 207 and the linearly polarized apertures 208, 209, 210. A mounting table 212 for mounting an object to be heated is provided in the heating chamber 202. The mounting table 212 in Embodiment 2 is made of a material that easily transmits microwaves, such as glass or ceramic.

  The circularly polarized wave used in the present invention is a technique widely used in the field of mobile communication and satellite communication as described in the first embodiment, and this circularly polarized wave is converted into a microwave heating device. This contributes to uniform heating of the object to be heated.

  In the microwave oven 201 of the second embodiment, X-shaped circularly polarized apertures 205, 206, and 207 are formed on both sides of the central axis P extending in the tube axis direction on the H plane of the waveguide 204, and each circle is formed. A circularly polarized wave is radiated from the polarization apertures 205, 206, and 207 into the heating chamber 202. The X-shapes of these circularly polarized apertures 205, 206, and 207 are formed by two elongated rectangular slits orthogonal to each other at the center point.

  Note that the relationship between the guide wavelength (λg) and the waveguide width (see symbol “a” in FIG. 4) in a general waveguide as a microwave transmission means is the same as in FIG. As described with reference to FIG. That is, as shown in Expression (1), the guide wavelength (transmission wavelength) λg varies depending on the width a dimension of the waveguide, but is independent of the height b dimension of the waveguide.

  In the microwave oven according to the second embodiment, which is an example of the microwave heating apparatus of the present invention, the waveguide as the microwave transmission means formed as described above is used to achieve uniform heating in order to achieve uniform heating. It is configured to radiate both a wave and a linearly polarized wave that is a microwave having a heating region different from the circularly polarized wave.

  Hereinafter, in the microwave oven of Embodiment 2, the structure which radiates | emits both circularly polarized wave and linearly polarized wave is demonstrated in detail.

  As shown in FIG. 10, each of the circularly polarized apertures 205, 206, and 207 in the second embodiment is formed on the H plane of the waveguide 204. It has an opening shape formed in a letter shape. The circularly polarized apertures 205, 206, and 207 are formed on both sides of the central axis P extending in the tube axis direction on the H plane of the waveguide 204, and one circularly polarized aperture 206 is on the back side of the central axis P ( The other circularly polarized apertures 205 and 207 are on the front side of the central axis P (lower side in FIG. 10; door side). As described above, the circularly polarized wave openings 205, 206, and 207 are arranged on either side of the central axis P extending in the tube axis direction on the H plane of the waveguide 204. By arranging in this way, a circularly polarized wave can be generated, and it can be divided into a right-handed polarized wave or a left-handed polarized wave depending on which of the central axes P of the H plane is approached.

  However, as described in the first embodiment, even if only the circularly polarized wave forming means is applied to an actual microwave oven, it cannot be heated uniformly by itself, and eventually the heating chamber is stirred. A driving mechanism such as a driving unit is required.

  As described above, since the microwave oven is used with the door 213 closed as described above, the space covered by the microwave is closed, and the microwave is repeatedly reflected in the heating chamber and the waveguide. This is thought to be due to the fact that there is a space where standing waves tend to occur. Regarding this, even in the configuration of the second embodiment, a certain knowledge has been obtained by simulation, which will be described below.

  13 to 15 are diagrams showing simulation results for clarifying the influence of the standing wave in the waveguide 202. FIG. In these simulations, the wall surface of the heating chamber 202 has a radiation boundary (a boundary condition in which microwaves do not reflect), has a simple configuration with only one X-shaped circularly polarized aperture 218, and the end of the waveguide 204. The condition of the part 219 (open or closed) is used as a parameter.

  FIG. 13 shows a simulation result when the end portion 219 of the waveguide 204a is opened to be a radiation boundary (a boundary condition in which the microwave is not reflected). FIG. 13A is a plan image diagram of a simulation model when a simulation is performed, and shows a simulation model shape when the heating chamber 202 is viewed from above. In FIG. 13A, the image when the simulation is performed is described as it is, and it is assumed that the potato Q is disposed as the object to be heated in the center of the heating chamber 202. FIG. 13B is an analysis result, and is a contour diagram of a plane cross section showing the electric field strength distribution in the heating chamber 202 as viewed from above. As shown in FIG. 13B, the heating chamber 202 is circularly polarized and the electric field is vortexed, the tube axis direction X of the waveguide 204a (the left-right direction in FIG. 13B), and The electric field distribution is also uniform in the width direction Y (the vertical direction in FIG. 13B) of the waveguide 204a.

  FIG. 14 shows a case where the end portion 222 of the waveguide 204b is closed to form a reflection boundary (a boundary condition in which microwaves are reflected), and an X-shaped circularly polarized wave opening 218 is defined in the waveguide 204b. The position of the end portion 222 is determined so as to be the position of the “antinode” of the standing wave. FIG. 14A is a contour diagram of a plane cross section showing the electric field strength distribution in the heating chamber 202 as viewed from above. FIG. 14B is a contour diagram of the electric field strength distribution of the cross section when the heating chamber 202 is viewed from the front.

  As shown in FIG. 14A, the electric field in the tube axis direction X of the waveguide 204b (the left-right direction in FIG. 14A) is strong, and a microwave is widely emitted from the circularly polarized aperture 218 in the tube axis direction X. Has been propagated. On the other hand, the electric field in the width direction Y (the vertical direction in FIG. 14A) of the waveguide 204b is weak and does not propagate much in the width direction from the circularly polarized wave opening 218.

  As shown in FIG. 14B, the strength of the electric field appears in the waveguide 204b below the heating chamber 202, and it is clear that a standing wave is generated. In FIG. 14B, reference numerals 223, 224, and 225 in the waveguide 204b indicate “antinodes”, and reference numerals 226 and 227 indicate “nodes”. In particular, as shown in FIG. 14B, the circularly polarized aperture 218 is formed at the position of the “wave” 226 of the standing wave. In this simulation, the distance in the transmission direction from the center position (center of gravity) of the circularly polarized aperture 218 to the end portion 222 is set to be ½ of the guide wavelength λg, and the standing wave is almost in the guide. It occurs in accordance with 1/2 of the wavelength λg.

  Based on the above, as a new finding, when a standing wave is generated in the waveguide, the circularly polarized wave radiated from the circularly polarized opening to the heating chamber is destroyed by the standing wave, and in particular, the circularly polarized opening is fixed. When located at the “node” of the standing wave, it was discovered that the microwave propagates weakly in the width direction of the waveguide and strongly in the tube axis direction.

  Therefore, if the direction in which the transmission becomes weak when the circularly polarized wave breaks can be predicted in advance, it will be possible to make the heating distribution uniform if it is configured to supplementarily supply microwaves. It was thought that there was no chance to recall the configuration of the second embodiment of the present invention.

  FIG. 15 shows a configuration that was studied before the configuration of the second embodiment according to the present invention was conceived. FIG. 15 is a schematic view when the bottom surface of the heating chamber 202 and the waveguide 204c are viewed from above, showing an example in which only the X-shaped circularly polarized apertures 205, 206, and 207 are formed on the H surface of the waveguide 204c. FIG.

  Compared to the configuration of the second embodiment shown in FIG. 10 described above, the configuration shown in FIG. 15 has linearly polarized apertures 208, 209, and 210 as second microwave supply units serving as auxiliary microwave supply means. The configuration is not formed.

  Before conceiving the configuration of the second embodiment according to the present invention, the present inventor believes that if a plurality of circularly polarized apertures are arranged in parallel in the waveguide 204c, the heating distribution becomes uniform. Thus, the arrangement shown in FIG. 15 was tried. However, in the arrangement configuration of FIG. 15, the area A shown by hatching in FIG. 15 is heated strongly, and the heating area spreads to some extent in the tube axis direction of the waveguide 204c, but is heated in the width direction. Was uneven and the heating distribution was not uniform.

  When the distance in the tube axis direction from the terminal end portion 211c of the waveguide 204c at this time to the center position (center of gravity position) of each circularly polarized aperture 205, 206, 207 is examined in detail, λg / 2, λg, Alternatively, the distance was either 3λg / 2. That is, the center positions (center-of-gravity positions) of all the circularly polarized apertures 205, 206, and 207 are arranged at the positions of “nodes” of standing waves generated in the waveguide 204c. Therefore, each of the three circularly polarized wave openings 205, 206, and 207 is positioned at a “node” of the standing wave in the waveguide 204c as shown in FIG. The circularly polarized apertures 205, 206, and 207 are considered to be in a state close to the contour diagram shown in FIG.

  The microwave oven according to the second embodiment of the present invention is configured as shown in FIG. 10 described above, and eliminates the problems in the configuration shown in FIG. As described above, in the configuration shown in FIG. 15, the propagation of the microwave radiated from the circularly polarized apertures 205, 206, and 207 into the heating chamber 202 is strong in the tube axis direction of the waveguide 204c, and is guided. It is weak in the width direction of the tube 204c. Therefore, in the waveguide 204 in the second embodiment, as shown in FIG. 10, linearly polarized wave apertures 208 as second microwave supply units, which are auxiliary microwave supply means for radiating linearly polarized waves, 209, 210 are formed. This is because, by forming long hole-shaped linearly polarized wave openings 208, 209, 210 on the H surface of the waveguide 204, the microwaves from these linearly polarized wave openings 208, 209, 210 are guided into the waveguide 204. It is considered that the heating chamber is made uniform by propagating in the width direction.

  In the microwave oven according to the second embodiment, as shown in FIG. 10, the linearly polarized wave openings 208, 209, and 210 that are the second microwave supply sections are elongated holes in the tube axis direction of the waveguide 204. is there. The linearly polarized wave openings 208, 209, and 210 are arranged on both sides of the central axis P extending in the tube axis direction of the waveguide 204, and each is formed at the end in the width direction on the H plane of the waveguide 204. ing. In the configuration of the second embodiment, the first microwave supply unit (circularly polarized wave opening 205, 206 or 207) is disposed so as to face each other across the central axis P extending in the tube axis direction of the waveguide 204. And a second microwave supply section (linearly polarized wave aperture 208, 209 or 210) is formed. The first microwave supply unit (circular polarization aperture 205, 206 or 207) and the second microwave supply unit (linear polarization aperture 208, 209 or 210) are arranged in the tube axis direction of the waveguide 202. They are arranged alternately. Specifically, in the configuration of the second embodiment, a circularly polarized wave aperture 205, a linearly polarized wave aperture 209, and a circularly polarized wave aperture 207 are provided on the front side of the central axis P extending in the tube axis direction of the waveguide 204. The linearly polarized wave aperture 208, the circularly polarized wave aperture 206, and the linearly polarized wave aperture 210 are linearly arranged in the tube axis direction on the back side from the central axis P. .

  The microwave oven according to the second embodiment configured as described above is formed in the heating region A that spreads in the tube axis direction by the circularly polarized wave openings 205, 206, and 207, which are the first microwave supply units, by the waveguide 204. In addition, the heating region B extending in the width direction can be heated together by the linearly polarized wave openings 208, 209, and 210 which are the second microwave supply units.

  As a result, in the heating chamber 202, it is difficult to heat by the first microwave supply unit (circularly polarized wave openings 205, 206, 207) as the circularly polarized wave supply means, and the area between each of the regions is defined as the auxiliary microwave supply means. The second microwave supply unit (linearly polarized wave openings 108, 109, 110) can be interpolated, and the object to be heated arranged in the heating chamber 202 can be heated uniformly. Become. In addition, according to the configuration of the second embodiment of the present invention, the microwave can be radiated strongly to the outer region in the width direction of the waveguide 204, and the uniform heating in the heating chamber can be achieved. .

  Hereinafter, a method of setting the formation positions of the linearly polarized wave openings 208, 209, and 210 as a second microwave supply unit that is an auxiliary microwave supply unit in the configuration of the second embodiment will be described.

  FIG. 16 is a plan view showing an H surface 237 on the tube wall of a general TE10 mode waveguide 236 configured in the same manner as the waveguide 136 (see FIG. 8) described in the first embodiment. . FIG. 16 shows the direction in which the conduction current flows in the H plane 237 at a certain moment, and shows that there are a spring point 238 and a suction point 239 at the center in the width direction. Assuming that the microwave is transmitted from the left to the right in FIG. 16 as indicated by the arrow Z, the spring point 238 and the suction point 239 also sequentially move to the right. However, the spring point 238 and the suction point 239 in the tube wall always occur at the center position in the width direction of the waveguide 236. However, in the waveguide 236, the conduction current that flows simultaneously with the conduction current flowing between the spring point 238 and the suction point 239 is not limited to the current flowing between the spring point 238 and the suction point 239. The electric current 241 from the point 238 flows through the E surface (not shown) to the H surface suction point (not shown) on the opposite back surface, or conversely, the opposite H surface on the opposite surface side. There is a current 242 in which a conduction current from a spring point (not shown) flows into the suction point 239 through the E plane (not shown). Therefore, by arranging the opening at an appropriate position in consideration of the direction of these currents, the direction of the microwave radiated from the opening can be freely set to the tube axis direction of the waveguide or the width direction of the waveguide. It becomes possible to select.

  For example, the elongated rectangular long hole-shaped opening 245 whose longitudinal direction is the tube axis direction shown in FIG. 16 prevents the current 242 flowing from the E-plane to the H-plane, so both ends of the opening 245 on the upper and lower sides in FIG. An electric field is generated so that a potential difference is generated at the (opposite end portion in the width direction), and microwaves can be strongly radiated in the vertical direction in FIG. 16, that is, in the width direction of the waveguide 236. The spring point 238 and the suction point 239 move to the right (in the direction of arrow Z in FIG. 16) with the passage of time, and such a long hole-shaped opening 245 generates a current in a direction perpendicular to the opening 245. As a result, the current in the up and down direction is always prevented. As a result, an electric field is generated at both ends of the opening 245 on the upper and lower sides in FIG. 16 (opposing ends in the width direction) so as to generate a potential difference, and the microwaves are formed in the vertical direction in FIG. Will be emitted strongly.

  Note that the elongated rectangular oblong hole-shaped opening 243 shown in FIG. 16 whose longitudinal direction is the width direction prevents the current 244 flowing from the spring point 238 in the right direction (transmission direction). An electric field is generated so as to generate a potential difference at both end portions (opposite end portions in the tube axis direction) on the side, and microwaves can be strongly emitted in the left-right direction in FIG. 16, that is, the tube axis direction of the waveguide 236. Become. The spring point 238 and the suction point 239 move to the right (in the direction of arrow Z in FIG. 16) with the passage of time, and such a long hole-shaped opening 243 generates a current in a direction perpendicular to the opening 243. As a result, the current in the left-right direction is always prevented. As a result, an electric field is generated so as to generate a potential difference at both the left and right ends of the opening 243 in FIG. 16 (opposite ends in the tube axis direction), and in the left and right direction in FIG. 16, that is, the tube axis direction of the waveguide 236. Microwaves will be emitted strongly.

  Therefore, in the microwave oven of the second embodiment, as the auxiliary microwave supply means (second microwave supply unit), linearly polarized apertures 208, 209, and 210 are formed on the H surface of the waveguide 204, as shown in FIG. As shown in the figure, it is a long hole shape elongated in the tube axis direction of the waveguide 204, and is disposed at both ends of the central axis P extending in the tube axis direction of the waveguide 204 at the end in the width direction. By forming the linearly polarized wave openings 208, 209, and 210 in this way, the current in the vertical direction in FIG. 10 is prevented in the same manner as the opening 245 shown in FIG. As a result, an electric field is generated so that a potential difference is generated between the upper and lower ends (opposite ends in the width direction) of FIG. 10 in the linearly polarized apertures 208, 209, and 210, and the vertical direction of FIG. The microwave is strongly radiated in the vertical direction (width direction). In FIG. 10, the hatching area | region B is described in the upper and lower sides of the linearly polarized wave opening 208,209,210, and the area | region where a microwave is radiated | emitted strongly is shown typically.

  As described above, the microwave oven 201 that is the microwave heating apparatus according to the second embodiment of the present invention includes the heating chamber 202 that stores an object to be heated, the magnetron 203 that is a microwave generation unit that generates a microwave, , And a waveguide 204 that transmits and supplies the microwave from the magnetron 103 to the heating chamber 102, and the waveguide 204 is a circle that generates a circularly polarized wave in the heating chamber 202 using the microwave. A microwave having a heating region (radiation direction) different from the circularly polarized wave from the circularly polarized wave supplying unit for uniformizing the heating distribution and the polarized wave supplying unit (first microwave supplying unit) is heated in the heating chamber 202. Auxiliary microwave supply means (second microwave supply unit) for supplying the inside.

  In the microwave heating apparatus (microwave oven 201) according to the second embodiment configured as described above, in addition to supplying the circularly polarized wave into the heating chamber by the circularly polarized wave supplying means, the auxiliary microwave supplying means also By supplying a microwave having a heating area different from the circularly polarized wave from the circularly polarized wave supplying means, it becomes possible to assist the heating area of the weak part only with the circularly polarized wave, without using a drive mechanism, In this configuration, the heating distribution of the object to be heated can be made uniform.

  In the microwave heating apparatus according to the second embodiment, the waveguide 204 that guides the microwave from the microwave generation unit to the heating chamber 202 is guided as a circularly polarized wave supply unit (first microwave supply unit). X-shaped circularly polarized apertures 205, 206, 207 provided on the H surface of the tube 204, and a long hole provided on the H surface of the waveguide 204 as auxiliary microwave supply means (second microwave supply unit) Shaped linearly polarized apertures 208, 209 and 210 are formed.

  In the waveguide 204 configured as described above, it is easy to radiate microwaves to the heating chamber 202 from the opening formed in the H surface which is the surface facing the heating chamber 202, and circular polarization is achieved. In addition to being able to radiate circularly polarized waves from the supply means (circular polarization openings 205, 206, 207) to the heating chamber 202, auxiliary microwave supply means (linear polarization openings 208, 209, 210) Since the microwave having a heating region different from the circularly polarized wave from the circularly polarized wave supply means can be supplied into the heating chamber 202 from the auxiliary, the heating distribution of the object to be heated with a very simple configuration without using a drive mechanism Can be made uniform.

  In the microwave heating apparatus of the second embodiment, the propagation direction of the microwave radiated into the heating chamber 202 from the circularly polarized apertures 205, 206, and 207 that are circularly polarized wave supplying means is the waveguide 204. Propagation in the width direction is weak, and propagation in the tube axis direction tends to be strong. For this reason, in the microwave heating apparatus of the second embodiment, linearly polarized wave openings 208, 209, and 210 that are auxiliary microwave supply means are provided. The microwaves radiated from the linearly polarized apertures 208, 209, and 210 are strongly propagated in the width direction of the waveguide 204, so that the heating chamber as a whole is made uniform. For this reason, as shown in FIG. 10, the linearly polarized wave openings 208, 209, and 210 have an elongated hole shape in the tube axis direction of the waveguide 204, and the tube axis direction on the H plane of the waveguide. It is arrange | positioned in the position outside the central axis P extended in this. In the configuration of the second embodiment, each of the linearly polarized apertures 208, 209, and 210 is arranged at the end portion in the width direction on the H plane of the waveguide.

  As described above, in the microwave heating apparatus according to the second embodiment, the linearly polarized wave openings 208, 209, and 210 are formed in a long and narrow shape in the tube axis direction of the waveguide 204, and are arranged at the end in the width direction. As a result, like the opening 245 of FIG. 16, the linearly polarized wave openings 208, 209, and 210 prevent the current flowing in the vertical direction of FIG. As a result, an electric field is generated so that a potential difference is generated between the upper and lower end portions (opposite end portions in the width direction) of FIG. 10 in the linearly polarized apertures 208, 209, and 210, and the vertical direction of FIG. It becomes the structure which can radiate | emit a microwave strongly in the width direction. Therefore, the microwave heating apparatus of the second embodiment can heat the hatched portion B (see FIGS. 10 and 16) that could not be heated only by the circularly polarized wave supply means (first microwave supply unit). The heating distribution of the object to be heated can be made uniform without using a drive mechanism.

  In the microwave heating apparatus according to the second embodiment, the circularly polarized apertures 205, 206, and 207 are arranged at the “nodes” of the electric field of the standing wave in the waveguide 204. A state in which propagation in the width direction is weak and propagation in the tube axis direction is strong can easily occur. However, as described above, the linearly polarized wave openings 208, 209, and 210 which are auxiliary microwave supply means (second microwave supply unit) are formed in a long and narrow shape in the tube axis direction of the waveguide 204, In addition, by disposing at a position outside the central axis P extending in the tube axis direction, propagation in the width direction of the waveguide 204 can be strengthened, and the heating region can be reliably compensated to prevent heating unevenness. Thus, the heating distribution of the object to be heated can be made uniform without using a driving mechanism.

  In the microwave heating apparatus of the second embodiment, the distance in the transmission direction from the center position (center of gravity position) of each circularly polarized aperture 205, 206, 207 to the terminal end 211 of the waveguide 204 is set to 1 of the guide wavelength λg. It is set to approximately an integer multiple of / 2. Thus, by determining the positions of the circularly polarized apertures 205, 206, and 27, the circularly polarized apertures 205, 206, and 207 actually become “nodes” of the electric field of the standing wave in the waveguide 204. It becomes the structure located in. As a result, as described above, with only the circularly polarized apertures 205, 206, and 207, the propagation in the width direction of the waveguide 204 is weak and the propagation in the tube axis direction may be strong. However, in the microwave heating apparatus of the second embodiment, linearly polarized apertures 208, 209, and 210 are guided on the H plane of the waveguide 204 as auxiliary microwave supply means (second microwave supply unit). By forming the tube 204 in the shape of a long and narrow hole in the tube axis direction and disposing it at the end in the width direction, it is possible to reliably compensate for heating so as not to cause uneven heating, and there is no drive mechanism. The heating distribution of the object to be heated can be made uniform.

  In the microwave heating apparatus of the second embodiment, the circularly polarized wave supplying means (first micro-wave supply means) is provided in one of the regions on both sides of the H plane with the central axis P extending in the tube axis direction of the waveguide 204 as a boundary. The circularly polarized apertures 205, 206, and 207 of the wave supply unit) and the linearly polarized apertures 208, 209, and 210 of the auxiliary microwave supply means (second microwave supply unit) are alternately arranged, and in the other region. The linearly polarized wave openings 208, 209, 210 of the auxiliary microwave supply means (second microwave supply part) and the circularly polarized wave openings 205, 206, 207 of the circularly polarized wave supply means (first microwave supply part) Are alternately arranged, and circularly polarized apertures 205, 206, 207 of the circularly polarized wave supply means (first microwave supply part) and a straight line of the auxiliary microwave supply means (second microwave supply part) Polarization apertures 208, 209, 2 0 is positioned on the width direction of the waveguide 204.

  In the microwave heating apparatus according to the second embodiment configured as described above, the auxiliary microwave supply unit (second microwave supply unit) heats the circularly polarized wave supply unit (first microwave supply unit). Unevenness can be compensated, and the heating distribution of the object to be heated can be made uniform without using a drive mechanism.

  In the microwave heating apparatus of the second embodiment, each of the circularly polarized wave supplying means (circularly polarized wave openings 205, 206, and 207) is arranged on either side with the central axis P in the width direction of the waveguide as a boundary, On the other hand, the auxiliary microwave supply means (linearly polarized wave apertures 208, 209, 210) are arranged at different positions that do not overlap each other. For this reason, the microwave heating device of the second embodiment can easily realize a desired waveguide by reliably arranging the circularly polarized wave supplying means and the auxiliary microwave supplying means in the waveguide.

  In the configuration of the second embodiment, three circularly polarized wave openings 205, 206, and 207 as circularly polarized wave supplying means, and three linearly polarized wave openings 208, 209, and 210 as auxiliary microwave supplying means, Although the description has been given using the configuration example provided, in the present invention, the number of circularly polarized wave supplying means and auxiliary microwave supplying means is not limited to such a number. In the second embodiment, the circularly polarized wave supplying means and the auxiliary microwave supplying means are described with the same number of configuration examples, but the present invention is not limited to the same number.

  As described above, the microwave heating apparatus according to the second embodiment of the present invention is provided with the circularly polarized wave supplying unit and the auxiliary microwave supplying unit, thereby heating the circularly polarized wave from the circularly polarized wave supplying unit. An area where heating by the circularly polarized wave from the circularly polarized wave supplying means is difficult is interpolated by the auxiliary microwave supplying means, and the object to be heated arranged in the heating chamber is uniformly heated without using a drive mechanism. It becomes the structure which can do.

In the present invention, the heating distribution in the heating chamber is compensated by supplementing the circularly polarized wave supplying means having a weak propagation in the specific direction from the waveguide to the heating chamber by the auxiliary microwave supplying means having a strong propagation in the specific direction. It is meaningful to make uniform. Therefore, as the auxiliary microwave supply means in the present invention, the effect can be exhibited if it is arranged so as to compensate for the weak heating of the heating chamber. Therefore, as a minimum condition, the opening of the circularly polarized wave supply means and the auxiliary microwave supply It is sufficient that there is at least one opening of the means. Of course, if the openings of the circularly polarized wave supplying means and the openings of the auxiliary microwave supplying means are alternately arranged as in the structure of the first embodiment and the structure of the second embodiment, there is no waste of the arrangement, and much more. Thus, it is possible to expect a uniform heating state.
In the present invention, as in the configuration of the second embodiment, the circularly polarized wave supplying means and the auxiliary microwave supplying means have the same number of openings and are arranged in a staggered manner (alternately). Further, there is no waste of the arrangement, and it can be expected that the heating state is made even more uniform.

  Note that the circularly polarized wave supplying means in the first and second embodiments has been described by taking an example of an X-shaped circularly polarized aperture that is formed on the tube wall of the waveguide and intersects. The circularly polarized wave supplying means is not limited to the X shape. As the circularly polarized wave supplying means, it is sufficient if there are two elongated rectangular slits arranged in a direction orthogonal to the tube wall of the waveguide, and may be configured in an L shape or a T shape, You may arrange | position apart like the above-mentioned patent document 2. FIG. The two slits do not have to be orthogonal to each other, and may be inclined if they are about 30 degrees.

  In the first and second embodiments, the example in which two rectangular slits are intersected as the circularly polarized wave supplying means has been described. However, the present invention is not limited to the rectangular shape. For example, it is possible to generate circularly polarized waves even if the corner portion of the opening shape is constituted by a curved surface (R) or the opening shape is made elliptical. As a basic idea of the opening shape of the circularly polarized wave supplying means, two elongated shapes having a long one direction and a short other direction perpendicular to the one direction may be combined. Further, the circularly polarized wave supplying means is not limited to a configuration in which an opening is formed in the waveguide, and may be configured by, for example, a patch antenna as disclosed in Patent Document 3 described above. The circularly polarized wave supply means of the present invention may be of any configuration that can generate circularly polarized waves.

  The auxiliary microwave supply means in the first and second embodiments is shown as a rectangular slit as a linearly polarized wave opening, but is not limited to a rectangle. For example, the corner portion of the opening shape may be configured by a curved surface (R), or the opening shape may be an elliptical shape. The basic concept of the opening shape of the auxiliary microwave supply means may be any shape that is elongated in one direction and short in the other direction perpendicular to the one direction. In the present invention, the opening of the auxiliary microwave supply means is the same as the configuration of the microwave heating apparatus of the first and second embodiments if the longitudinal direction of the elongated shape is directed in the width direction of the waveguide. It is effective.

  In addition, although the description has been given using the linearly polarized wave aperture as the auxiliary microwave supply unit in the first and second embodiments, the auxiliary microwave supply unit is heated by the circularly polarized wave from the circularly polarized wave supply unit. Any means for supplying a microwave having a heating area (radiation direction) different from the circularly polarized wave from the circularly polarized wave supplying means may be used as long as it has a function of assisting difficult areas. It ’s fine.

  Since the microwave heating apparatus of the present invention can uniformly irradiate the object to be heated with microwaves, it can be effectively used for a microwave heating apparatus that performs heating processing or sterilization of food.

101,201 Microwave oven (microwave heating device)
102,202 Heating chamber 103,203 Magnetron (microwave generator)
104, 204 Waveguides 105a, 105b, 106a, 106b, 107a, 107b, 205, 206, 207 Circularly polarized aperture (first microwave supply unit)
108, 109, 110, 208, 209, 210 Linearly polarized aperture (second microwave supply unit)
111, 211 terminal

Claims (13)

A heating chamber for storing an object to be heated;
A microwave generator for generating microwaves;
A waveguide that transmits microwaves from the microwave generation unit and supplies the microwaves to the heating chamber, and the waveguide includes:
A first microwave supply section for supplying a circularly polarized microwave into the heating chamber;
A microwave heating apparatus comprising: a second microwave supply unit configured to supply a microwave having a heating region different from the circularly polarized wave from the first microwave supply unit into the heating chamber. The first microwave supply unit is a circularly polarized aperture provided on an H surface of the waveguide facing the heating chamber.
The microwave heating apparatus according to claim 1, wherein the second microwave supply unit is an opening provided in the waveguide.   The second microwave supply unit is provided on the H surface of the waveguide provided with the first microwave supply unit, and supplies a linearly polarized microwave to the heating chamber. The microwave heating device according to claim 2.   The second microwave supply section is an opening that has an elongated shape in which the width direction of the waveguide is a longitudinal direction, and is disposed at a substantially central portion in the width direction of the waveguide. 3. The microwave heating apparatus according to 3.   The circularly polarized aperture is disposed at the antinode position of the electric field of the standing wave in the waveguide, and the microwave radiation from the circularly polarized aperture has a strong propagation in the width direction of the waveguide, The microwave heating device according to any one of claims 2 to 4, wherein the propagation of the waveguide in the tube axis direction is weak.   The distance in the transmission direction from the center position of the circularly polarized aperture to the end portion of the waveguide is set to be an odd number times 1/4 of the guide wavelength, so that the circularly polarized aperture is a standing wave in the waveguide. The microwave heating device according to any one of claims 2 to 5, wherein the microwave heating device is configured to be disposed on an antinode of the electric field.   The circularly polarized wave opening of the first microwave supply unit and the opening of the second microwave supply unit are configured to be arranged at different positions in the tube axis direction of the waveguide. The microwave heating device according to any one of the above.   The microwave heating device according to any one of claims 2 to 7, wherein at least one opening in the second microwave supply unit is disposed at a substantially end position in a transmission direction of the waveguide.   The micro of any one of claims 2 to 8, wherein at least one opening in the second microwave supply section is disposed between two circularly polarized openings in the first microwave supply section. Wave heating device.   The second microwave supply section has an elongated shape whose longitudinal direction is the tube axis direction of the waveguide, and is an opening disposed at a position outside the central axis extending in the tube axis direction of the waveguide. The microwave heating device according to claim 2 or 3.   The circularly polarized aperture is disposed at a node of an electric field of a standing wave in the waveguide, and the microwave radiation from the circularly polarized aperture is weakly propagated in the width direction of the waveguide, and the guide The microwave heating device according to any one of claims 2, 3 and 10, wherein the wave tube has a strong propagation in the tube axis direction.   The distance in the transmission direction from the center position of the circularly polarized aperture to the terminal end of the waveguide is set to be approximately an integral multiple of 1/2 of the guide wavelength, and the circularly polarized aperture is a standing wave in the waveguide. The microwave heating device according to any one of claims 2, 3, 10, and 11, wherein the microwave heating device is arranged at a node of the electric field.   In a region on both sides of the H plane with a central axis extending in the tube axis direction of the waveguide as a boundary, the circularly polarized wave opening of the first microwave supply unit and the second microwave supply in one region The openings of the second microwave supply unit and the circularly polarized wave openings of the first microwave supply unit are alternately arranged in the other region, and the first micro The circularly polarized wave opening of the wave supply unit and the opening of the second microwave supply unit are arranged in the width direction of the waveguide, according to any one of claims 2, 3, 10, 11, and 12. Microwave heating device.

Images