JP6861397B2 - Microwave heating device - Google Patents

Description

The present invention relates to a microwave heating device such as a microwave oven that radiates microwaves to an object to be heated to dielectrically heat them, and particularly relates to an antenna structure that radiates microwaves.

In a microwave oven, which is a typical microwave heating device, microwaves formed by a magnetron, which is a microwave generator, are radiated into a metal heating chamber, and an object to be heated is arranged inside the heating chamber. Is dielectric heated.

In recent years, in microwave ovens, products have been provided in which the bottom surface of a heating chamber on which an object to be heated is placed is formed on a flat surface, and an antenna for radiating microwaves is provided below the bottom surface. In the heating chamber whose bottom surface is formed on a flat surface in this way, it is desirable that the object to be heated is uniformly heated regardless of the region of the bottom surface. In the field of microwave ovens, various antenna structures have been proposed for the purpose of substantially uniformly heating the entire heating chamber.

For example, Patent Document 1 proposes a configuration in which an antenna having a waveguide structure is provided below the bottom surface of the heating chamber. The waveguide structure antenna proposed in Patent Document 1 is a rotating antenna having a waveguide structure having a fan shape in a plan view, which is connected to a waveguide that transmits microwaves from a magnetron. In this waveguide-structured antenna, a fan-shaped arc portion is opened as a microwave emission port, and a portion other than the arc portion is provided with a shielding portion of a low impedance portion that reflects microwaves. An antenna having a waveguide structure configured in this way rotates around an axis extending in the vertical direction on the lower side of the bottom surface of the heating chamber, thereby causing microwaves in all directions in the horizontal direction on the lower side of the bottom surface of the heating chamber. Is radiated.

In the configuration of the microwave oven disclosed in Patent Document 1 configured as described above, since the rotation axis of the antenna is provided directly below the center of the bottom surface of the heating chamber, it is placed in the central region of the bottom surface of the heating chamber. It was not possible to radiate microwaves directly to the object to be heated, and it was difficult to uniformly heat the object to be heated placed in all areas inside the heating chamber. ..

A microwave oven disclosed in Patent Document 2 is a configuration that directly radiates microwaves to an object to be heated placed in a central region on the bottom surface of a heating chamber. The microwave oven disclosed in Patent Document 2 is provided with an antenna having a waveguide structure below the central region on the bottom surface of the heating chamber. The waveguide-structured antenna disclosed in Patent Document 2 has a substantially quadrangular plane view, and is configured such that the three sides of the four sides are orthogonal to each other in a straight line. The remaining one side is formed in an arc shape, and the arc shape side is open, so that the microwave transmitted inside the waveguide structure of the antenna is radiated in the horizontal direction. In the waveguide-structured antenna disclosed in Patent Document 2, side wall surfaces are formed on three linear side portions, and further, low impedance extending in the horizontal direction from the lower ends of the side wall surfaces of the three side portions. The part is formed. In the waveguide-structured antenna disclosed in Patent Document 2 configured in this way, the leakage of microwaves transmitted inside the waveguide structure from the three sides is suppressed. Further, in the antenna having a waveguide structure disclosed in Patent Document 2, an opening for radiating circularly polarized waves is formed in the upper wall thereof to heat the object to be heated arranged in the central region of the heating chamber. ing.

Special Publication No. 63-53678 Japanese Unexamined Patent Publication No. 2016-119251

In the configuration of the microwave oven disclosed in Patent Document 1 and Patent Document 2 configured as described above, an antenna having a waveguide structure arranged under the bottom surface of the heating chamber is provided to be uniform in the heating chamber. It is configured to heat.

However, in the microwave ovens disclosed in Patent Document 1 and Patent Document 2, since the antenna has a waveguide structure configured to transmit microwaves in a predetermined direction, the antenna structure is large and complicated. In addition, since the antenna is arranged under the bottom surface of the heating chamber, it is necessary to secure a space having a certain size under the bottom surface of the heating chamber.

In the field of home appliances, due to changes in lifestyle, it has small capacity specifications, miniaturization, low price, and high reliability while maintaining high functionality so that it can accommodate a small number of households. The product is in demand. For this reason, for example, even in the field of microwave heating devices such as microwave ovens, it has high functionality even if the capacity of the heating chamber is small, and it is compact, inexpensive, and reliable for small households. Highly high-quality configuration is required.

The waveguide-structured antenna used in the microwave oven disclosed in Patent Document 2 is capable of radiating microwaves in a desired direction and has a high-performance configuration, but the structure is complicated. Due to its large size, the manufacturing cost is high, and since the antenna has a waveguide structure, a large space is required as the arrangement position of the antenna. Therefore, in the configuration disclosed in Patent Document 2, a microwave oven capable of achieving high functionality, miniaturization, and low price while having a small capacity is provided so as to accommodate a small number of households. Was difficult.

According to the present invention, it is possible to uniformly heat an object to be heated in a heating chamber, and even if the specifications of the device are small in capacity so as to accommodate a small number of households in accordance with changes in lifestyle. It is an object of the present invention to provide a highly reliable microwave heating device that achieves miniaturization and price reduction while maintaining high functionality.

The microwave heating device according to one aspect of the present invention is
A heating chamber with a flat bottom surface on which the object to be heated is placed,
A power supply chamber formed on the lower side of the bottom surface of the heating chamber and
A flat antenna provided inside the power supply chamber and having an antenna surface rotating in the same horizontal plane,
A waveguide coupled so as to be capable of microwave transmission via an antenna shaft provided at the center of rotation of the flat antenna.
A microwave forming unit for forming microwaves transmitted to the waveguide is provided.
The antenna surface of the flat antenna has at least one microwave emission port including an aperture shape in which two elongated openings intersect.
Each of the longitudinal centerlines of the two elongated openings constituting the at least one microwave emission port connects the rotation center of the flat antenna and the intersection in the shape where the two elongated openings intersect. It is configured to radiate circularly polarized light from the at least one microwave emission port in the direction directly above the antenna surface at an angle with respect to the position defining line extending to.

According to the present invention, there is provided a highly reliable microwave heating device capable of uniformly heating an object to be heated in a heating chamber, and achieving miniaturization and price reduction while maintaining high functionality. can do.

Perspective view showing the appearance of the microwave oven which is the microwave heating apparatus of Embodiment 1 which concerns on this invention. Cross-sectional view of the main body of the microwave oven of the first embodiment as viewed from the front A plan view showing a flat plate antenna or the like provided on the lower side of the bottom surface of the heating chamber in the microwave oven of the first embodiment. A side view showing a microwave oven unit and the like in the microwave oven of the first embodiment. FIG. 5 is an enlarged cross-sectional view showing a coupling portion between the waveguide and the flat plate antenna in the microwave oven of the first embodiment. Top view showing the shape of the flat surface of the flat antenna according to the first embodiment. The figure which shows the analysis result about the flat plate antenna in Embodiment 1. A plan view showing a modification of the flat antenna according to the first embodiment. A plan view showing a flat surface of a flat antenna in a microwave oven according to a second embodiment of the present invention. The figure which shows the analysis result about the flat plate antenna in Embodiment 2. A plan view showing a flat surface of a flat antenna in a microwave oven according to a third embodiment of the present invention. The figure which shows the analysis result about the flat plate antenna in Embodiment 3. The figure which shows the flat surface of the flat plate antenna in the microwave oven of Embodiment 4 which concerns on this invention, and shows the analysis result about the flat plate antenna. The figure which shows the modification of the flat plate antenna in the microwave oven of Embodiment 4 and shows the analysis result about the modification. The figure which shows the further modification of the flat plate antenna in the microwave oven of Embodiment 4, and shows the analysis result about the modification.

First, various aspects of the microwave heating device of the present invention will be described.
The microwave heating device of the first aspect according to the present invention is
A heating chamber with a flat bottom surface on which the object to be heated is placed,
A power supply chamber formed under the bottom surface of the heating chamber,
A flat antenna provided inside the power supply chamber and having an antenna surface that rotates in the same horizontal plane,
It is provided with a waveguide coupled so as to be capable of microwave transmission via an antenna shaft provided at the center of rotation of the flat plate antenna, and a microwave forming unit for forming microwaves transmitted to the waveguide.
The antenna surface of the flat antenna has at least one microwave emission port including an aperture shape in which two elongated openings intersect.
Each of the longitudinal centerlines of the two elongated openings constituting the at least one microwave emission port connects the rotation center of the flat antenna and the intersection in the shape where the two elongated openings intersect. It is configured to radiate circularly polarized light from the at least one microwave emission port in the direction directly above the antenna surface at an angle with respect to the position defining line extending to.

The microwave heating device of the first aspect configured as described above can uniformly heat the object to be heated in the heating chamber, and is compact while maintaining high functionality despite its simple configuration. It is possible to provide a highly reliable microwave heating device that has achieved low cost and low price.

In the microwave heating device of the second aspect according to the present invention, the antenna plane in the first aspect is divided into a plurality of regions by a line extending radially from the rotation center, and in the divided regions. Adjacent regions may be configured by the same plane having different shapes in a plan view.

In the microwave heating device of the third aspect according to the present invention, the at least one microwave emission port in the second aspect may be provided in at least one region in the divided region.

In the microwave heating device of the fourth aspect according to the present invention, in the divided region of the second or third aspect, at least one of the above-mentioned at least one region is located between the rotation centers and the opposite regions. A microwave emission port may be provided.

In the microwave heating device of the fifth aspect according to the present invention, the center lines in the longitudinal direction of the two elongated openings constituting the at least one microwave emission port in the first aspect are orthogonal to each other. May be good.

In the microwave heating device of the sixth aspect according to the present invention, at the intersection angle of the center line in the longitudinal direction of the two elongated openings constituting the at least one microwave emission port in the first aspect. The angle of the region facing the center of rotation may be narrower than 90 degrees.

In the microwave heating device of the seventh aspect according to the present invention, the antenna surface in the second or third aspect has two first arc regions and two first arc regions by a line extending radially from the rotation center. It has a configuration divided into four regions, a second arc region having a smaller radius than each of the first arc regions and a rectangular region, and the second arc region and the rectangular region are provided on both sides of the first arc region. May be provided, and at least one microwave emission port may be provided in each of the two first arc regions.

In the microwave heating device of the eighth aspect according to the present invention, a microwave emission port having the same length in the longitudinal direction of the two elongated openings in the seventh aspect may be provided in the rectangular region. ..

In the microwave heating device of the ninth aspect according to the present invention, in the first to seventh aspects, the length in the longitudinal direction of the two elongated openings constituting the at least one microwave emission port is It may have a different configuration.

In the microwave heating device of the tenth aspect according to the present invention, in the second and third aspects described above, the antenna surface is divided into an arc region and a rectangular region by a line extending radially from the center of rotation. , The at least one microwave emission port is provided in the arc region.
The two elongated openings constituting the at least one microwave emission port may have different lengths in the longitudinal direction.

In the microwave heating device of the eleventh aspect according to the present invention, the antenna surface in the first aspect has a substantially circular shape in a plan view, and the at least one microwave emission port has a shape. The intersection may be arranged at a position eccentric from the center of rotation, and the lengths of the two elongated openings constituting the at least one microwave emission port in the longitudinal direction may be different.

In the microwave heating device according to the twelfth aspect of the present invention, the microwave radiating port including the shape in which the two elongated openings intersect in the first to eleventh aspects faces the antenna shaft. The edge of the opening may not have an acute-angled portion.

Hereinafter, preferred embodiments of the microwave heating device according to the present invention will be described with reference to the accompanying drawings. A microwave oven will be described in the microwave heating device of the following embodiment, but the microwave oven is an example, and the microwave heating device of the present invention is not limited to the microwave oven and uses dielectric heating. It includes a microwave oven heating device such as a heating device, a garbage processor, or a semiconductor manufacturing device. Further, the present invention is not limited to the configuration having only the dielectric heating function of the following embodiments, for example, a heater heating function by radiant heating of a heater, a convection heating function by circulation of hot air, and steam by steam. It includes a configuration in which each heating function such as a heating function is added to the dielectric heating function individually or in combination.

<< Embodiment 1 >>
FIG. 1 is a perspective view showing the appearance of a microwave oven, which is a microwave oven according to a first embodiment of the present invention. As shown in FIG. 1, the microwave oven of the first embodiment has a main body 1 having a heating chamber 2 having an opening (heating chamber opening 2a) on the front surface of the microwave oven, and a door for opening and closing the heating chamber 2. It is a configuration having 3 and. On the right side of the main body 1 of the microwave oven according to the first embodiment, an operation unit 4 for performing various operations such as cooking setting and cooking start of cooking is arranged.

In the microwave oven of the first embodiment, the flat antenna 7 (see FIG. 2) is composed of a flat plate for radiating microwaves inside the heating chamber 2 in which the object to be heated is housed and placed. ) Is provided below the flat bottom surface T of the heating chamber 2. The object to be heated placed inside the heating chamber 2 is dielectrically heated by microwaves radiated from the flat antenna 7. The wall surface of the heating chamber 2 is provided with an internal light that illuminates the inside of the heating chamber 2, and various temperature detection sensors for detecting the surface temperature of the object to be heated and the internal temperature (heating chamber temperature). Further, in the microwave oven of the first embodiment, a position detection sensor for detecting in which region inside the heating chamber 2 the object to be heated is placed, for example, an infrared sensor is provided.

As shown in FIG. 1, in the microwave oven of the first embodiment, a rotation shaft (hinge) is provided at a position lower than the heating chamber opening 2a in the door 3, and the user can use the door 3 of the microwave oven. It has a structure in which the handle 3a on the upper side is gripped and pulled toward the front side to open the heating chamber opening 2a. The inside of the heating chamber 2 is substantially sealed due to the closed state of the door 3, and the object to be heated arranged inside the heating chamber 2 is cooked in a substantially sealed state.

FIG. 2 is a cross-sectional view of the main body 1 of the microwave oven of the first embodiment as viewed from the front. In the following description, the left-right direction of the microwave oven of the first embodiment means the left-right direction in the heating chamber 2 shown in FIG. 2, and the front-rear direction is a direction perpendicular to the paper surface of FIG. It means the direction connecting the front side (front side) and the back side (back side) of the heating chamber 2.

As shown in FIG. 2, in the microwave oven of the first embodiment, the bottom surface T of the heating chamber 2 on which the object to be heated is placed is formed on a flat surface. Below the bottom surface T of the heating chamber 2, a microwave radiation unit 10 including a flat-plate antenna 7 that forms and emits microwaves is provided. In the microwave oven of the first embodiment, in the space behind the operation unit 4 on the right side of the heating chamber 2, circuit parts such as a power supply circuit, a control circuit, and an operation circuit, a magnetron 5 forming a microwave, and a cooling fan And other components are arranged.

The microwave radiation unit 10 provided below the bottom surface T of the heating chamber 2 radiates the microwave to the heating chamber 2 and the waveguide 6 that transmits the microwave from the magnetron 5 that is the microwave forming portion. A flat antenna 7 and an antenna motor 8 for rotating the flat antenna 7 are included. The flat antenna 7 is provided with a metal antenna shaft 9 which is rotatable on a waveguide 6 and is coupled so as to be capable of microwave transmission. The antenna shaft 9 and the drive shaft of the antenna motor 8 are made of resin. It is joined by a rotary shaft 11 made of.

As shown in FIG. 2, in the upper surface wall of the waveguide 6 extending to the left and right, the output end 5a of the magnetron 5 is projected at a position of approximately 1/2 wavelength from the right end thereof. The microwave output from the output end 5a is transmitted in the waveguide 6 extending linearly to the left and right. In the waveguide 6 according to the first embodiment, the height H2 in the lower region (left region of the waveguide 6) of the bottom surface T of the heating chamber 2 is the region on the output end 5a side (right region of the waveguide 6). ) Is formed lower than the height H1 (H2 <H1). In the configuration of the first embodiment, the height H2 of the left side region of the waveguide 6 is about 1/2 the height of the height H1 of the right side region of the waveguide 6.

Since the height H2 of the left side region of the waveguide 6 is formed to be low, a space for arranging the antenna motor 8 joined to the rotating shaft 11 penetrating the waveguide 6 is secured. Therefore, in the waveguide 6, the lower surface wall of the substantially intermediate region connecting the left side region and the right side region of the waveguide 6 is formed on the slope 6a. It should be noted that the waveguide 6 has a recess inside the waveguide in order to achieve impedance matching with the antenna side and to define the positions of the antinodes and nodes of the standing wave formed in the waveguide 6. The matching portion 6b is formed in the left side region of the waveguide 6. Further, in the right side region of the waveguide 6, a downwardly bulging 6c is formed on the lower surface wall facing the protruding portion of the output end 5a of the magnetron 5, and between the output end 5a and the lower surface wall. The desired distance is secured.

In FIG. 2, the antenna shaft 9 of the flat plate antenna 7 is provided at a position approximately 1/2 wavelength from the left end on the upper wall of the waveguide 6 extending to the left and right. As described above, the antenna shaft 9 is rotatably coupled to the upper wall of the waveguide 6 so that microwaves can be transmitted, and the microwave transmitted through the waveguide 6 is joined to the antenna shaft 9. Power is supplied to the flat plate antenna 7 of the metal flat plate. A resin rotating shaft 11 is joined to the lower end of the antenna shaft 9, and the rotating shaft 11 is integrated with the antenna shaft 9 and penetrates the waveguide 6 up and down to the lower side of the waveguide 6. It is joined to the provided antenna motor 8.

FIG. 3 is a plan view showing a flat plate antenna 7 and the like of the microwave radiation unit 10 provided below the bottom surface T of the heating chamber 2. In the plan view of FIG. 3, the state in which the heat-resistant glass serving as the bottom surface T of the heating chamber 2 is removed is shown. Further, in the space adjacent to the right side of the heating chamber 2 shown in FIG. 3 (the region on the back side of the operation unit 4), the right region of the waveguide 6 and the magnetron 5 are shown, and other parts are omitted. In FIG. 3, the area indicated by the diagonal line is the area where the heat-resistant glass serving as the flat bottom surface T of the heating chamber 2 is provided, and in the first embodiment, the bottom surface shape of the heating chamber 2 is substantially square.

As shown in FIG. 3, a feeding chamber 13 which is a recessed space is provided under the bottom surface T of the heating chamber 2, and a flat antenna 7 is arranged at a substantially central position of the feeding chamber 13. The power supply chamber 13 is made of a metal material except for the upper surface thereof, and is configured to reflect microwaves from the flat antenna 7. The flat antenna 7 is made of a flat metal plate, for example, an aluminum-plated steel plate having a thickness of 0.5 mm, and has a plurality of openings (microwave emission ports 17, 18, 19) having a specific shape as described later. doing. Further, the flat antenna 7 according to the first embodiment has a specific shape even in the outer shape in a plan view.

As shown in FIG. 3, the shapes of the flat plate antenna 7 in the plan view (antenna surface) in the first embodiment are a fan-shaped arc region (14, 15) having different radii and a substantially rectangular rectangular region (16). It is configured to form the same plane by. Details of the outer shape of the flat antenna 7 will be described later. The flat antenna 7 is configured to rotate on the same plane with the center of the antenna shaft 9 as the center of rotation, from the outer periphery of the flat antenna 7 (antenna surface) in all directions in the horizontal direction, and from a plurality of openings in the vertical direction. The structure is such that microwaves are emitted to the antenna.

The power supply chamber 13 provided with the flat antenna 7 has an elongated space shape having a narrow width in the front-rear direction, and the center position of the heating chamber 2 and the center position of the power supply chamber 13 coincide with each other (FIG. 3). reference). The center position of the power feeding chamber 13 is the rotation center of the flat antenna 7. Further, the front, rear, left, and right side walls of the power feeding chamber 13 are inclined so as to face upward, and the microwaves radiated horizontally from the flat antenna 7 are reflected to the heating chamber 3 side (upper side). Has a function. The inclination angles of the front and rear side walls in the power supply chamber 13 are gentler than the inclination angles of the left and right side walls in the power supply chamber 3, and the reflected microwaves are formed so as to face upward. There is. This is because in the power supply chamber 13 having a narrow width in the front-rear direction, the microwaves reflected by the front and rear side walls of the power supply chamber 13 spread widely in the front and rear regions of the heating chamber 2.

FIG. 4 is a side view showing a configuration in which the magnetron 5 which is a microwave forming portion is provided in the microwave radiation unit 10, and the feeding chamber 13, the waveguide 6, the flat plate antenna 7, and the like are shown in cross section. .. FIG. 5 is an enlarged cross-sectional view showing a coupling portion between the waveguide 6 and the flat antenna 7.

As shown in FIGS. 4 and 5, a part (lower end portion) of the antenna shaft 9 of the flat plate antenna 7 is arranged in the waveguide 6, and the rotating shaft 11 joined to the lower end portion is waveguideed. It penetrates the lower surface wall of the tube 6 and is joined to the antenna motor 8. Further, an antenna holding portion 6d having an upwardly bulging shape is formed on the upper surface wall of the waveguide 6. A hole through which the antenna shaft 9 penetrates is formed in the antenna holding portion 6d, and an antenna receiver 12 made of wear-resistant resin is mounted on the outer periphery of the hole. The antenna receiver 12 has a through hole 12a penetrated by the antenna shaft 9. Further, the antenna receiver 12 is formed with a plurality of holding portions 12b projecting upward, and at least three upper end surfaces of the holding portions 12b support the flat plate antenna 7 so as to slide. The flat surface (antenna surface) A, which is the upper surface of the flat antenna 7, is reliably held at a desired position (horizontal plane). The flat antenna 7 has a flat surface in which the flat surface A on the upper surface functions as an antenna surface. Therefore, the flat surface A of the flat antenna 7 is driven by the antenna motor 8 to rotate in the same horizontal plane substantially parallel to the horizontal plane.

FIG. 6 is a plan view showing the shape of the flat surface A of the flat antenna 7 according to the first embodiment in a plan view. As shown in FIG. 6, in the microwave oven of the first embodiment, three openings (17, 18, 19) are formed. Since these openings (17, 18, 19) are formed on the flat surface A of the flat antenna 7, a plurality of circularly polarized waves and linearly polarized waves are directed directly upward from the flat surface A of the rotating flat antenna 7. It is a radiated configuration.

As shown in FIG. 6, the flat plate antenna 7 has two fan-shaped first arc regions 14 and 14 located opposite to each other with the rotation center P of the antenna shaft 9 in between. A fan-shaped second arc region 15 formed in one region of the region sandwiched between the two first arc regions 14 and 14 and the other region sandwiched between the two first arc regions 14 and 14. A plane is formed by the rectangular region 16 formed in the above. That is, the upper surfaces of the two first arc regions 14, 14 are located at opposite positions with the rotation center P of the antenna shaft 9 in between, and are included in the same plane. Further, the upper surfaces of the second arc region 15 and the rectangular region 16 are located at opposite positions with the rotation center P of the antenna shaft 9 in between, and are included in the same plane. As is clear from FIG. 6, the fan shape of the first arc regions 14 and 14 is a fan shape having a larger radius than the fan shape of the second arc region 15. As described above, the flat surface (antenna surface) A of the flat antenna 7 is divided into four regions by a line extending radially from the center of rotation P, and the adjacent regions in the divided regions are in plan view. The shape is different.

As described above, the plan view shape of the flat plate antenna 7 in the first embodiment has four regions in the same plane, which are the two first arc regions 14, 14, the second arc region 15, and the rectangular region 16. It is composed of. In the first embodiment, for example, the center angle of the first arc region 14 is about 80 degrees, the center angle of the second arc region 15 is about 100 degrees, and the center angle of the rectangular region 16 is about 100 degrees. As for the radius dimension of the flat plate antenna 7 in the first embodiment, for example, the radius of the first arc region 14 is 60 mm, and the radius of the second arc region 15 is 45 mm. Further, the outer side of the rectangular area 16 (the right end side in FIG. 6) is formed at a position 70 mm from the center of rotation P, and is a substantially quadrangular projecting area (protruding to the right side in FIG. 6) in the rectangular area 16. The width of the rectangular area) was 50 mm. The radius of the first arc region 14 is set to 60 mm in consideration of the length of about one wavelength of the frequency (2.45 GHz) used in the microwave oven.

As described above, the shape of the flat plate antenna 7 in the plan view in the first embodiment has been described with specific dimensions, but this specific example is a configuration example and is appropriately changed according to the specifications of the microwave oven. The present invention is not specified in this configuration example.

Regarding the three openings (17, 18, 19) formed in the flat antenna 7 in the first embodiment, the first microwave emission port 17, the second microwave emission port 18, and the third microwave emission port 19 Will be described below.

The first microwave emission port 17 and the second microwave emission port 18 in the first embodiment have the same opening shape, and are the longitudinal center lines (J) of elongated openings (20, 21) of the same length. , K) is an orthogonal cross opening shape. That is, the first microwave emission port 17 and the second microwave emission port 18 have the same X-shape.

In the cross-opening shape (X-shape) of the first microwave emission port 17, the center line (J or K) in the longitudinal direction of each of the two elongated openings (20, 21) is the center of rotation P of the antenna shaft 9. It forms an angle of 45 degrees with respect to a straight line (first position defining line E) connecting the intersection B having a cross opening shape. Similarly, in the cross opening shape of the second microwave emission port 18, the center line (J or K) in the longitudinal direction of each of the two elongated openings (20, 21) crosses the rotation center P of the antenna shaft 9. It forms an angle of 45 degrees with respect to a straight line (first position defining line E) connecting the opening-shaped intersection C. That is, in the cross-opening shape (substantially X-shaped) of the first microwave emission port 17, the center line J extending in the longitudinal direction of the first opening 20 is the intersection B of the rotation center P of the antenna shaft 9 and the cross-opening shape. It forms an angle of 45 degrees with respect to the first position defining line E connecting the above. Similarly, the center line K extending in the longitudinal direction of the second opening 21 forms an angle of 45 degrees with respect to the first position defining line E.

In the cross-opening shape of the first microwave emission port 17 and the second microwave emission port 18, the end portion and the bent portion are all formed of curved surfaces in order to prevent electric discharge. The first opening 20 and the second opening 21 in the cross-opening shape of the first embodiment have an elongated opening formed from the left back side to the right front side when viewed from the rotation center P of the flat plate antenna 7. A long and narrow opening formed from the right back side to the left front side is referred to as a second opening 21. In the following description of each embodiment, the positional relationship between the first opening and the second opening in the (omitted) cross opening shape is the same.

The first microwave emission port 17 and the second microwave emission port 18 are arranged so as to face each other with the rotation center P of the antenna shaft 9 in between, and are arranged in the first arc regions 14 and 14 having a large radius, respectively. It is formed. The straight line (first position defining line E) connecting the intersections (B, C) of the cross-opening shapes of the first microwave emission port 17 and the second microwave emission port 18 passes through the rotation center P of the antenna shaft 9. The first position defining line E is a center line that divides the first arc regions 14 and 14 into substantially the same area.

The specific cross opening shape of the first microwave emission port 17 and the second microwave emission port 18 in the first embodiment has a length in the longitudinal direction of the elongated opening, for example, 35 mm, and the width of the elongated opening. However, for example, it is 10 mm. These numbers are examples and do not specify the present invention to these numbers.

The third microwave emission port 19 in the first embodiment has an opening shape larger than that of the first microwave emission port 17 and the second microwave emission port 18 described above. The third microwave emission port 19 is formed in the rectangular region 16. The third microwave emission port 19 has a substantially cross opening shape including a cross opening shape in which elongated openings of the same length intersect at right angles. Further, as shown in FIG. 6, the substantially cross opening shape of the third microwave emission port 19 is such that one region G of the outer region divided into four regions by the cross opening shape opens in a substantially triangular shape. It includes the triangular-shaped opening. Further, in the substantially cross opening shape of the third microwave emission port 19, the center line in the longitudinal direction of each of the two elongated openings connects the rotation center P of the antenna shaft 9 and the intersection D of the substantially cross opening shape. It has an angle of 45 degrees with respect to a straight line (second position defining line F).

As shown in FIG. 6, the substantially cross opening shape of the third microwave emission port 19 includes a cross opening shape (X-shape) in which elongated openings of the same length are orthogonal to each other and an antenna shaft in the outer region of the cross opening shape. The region G facing the rotation center P of 9 is formed by a substantially triangular opening shape. This is because the third microwave emission port 19 has a larger opening shape than the first microwave emission port 17 and the second microwave emission port 18, and the electric field becomes stronger at the third microwave emission port 19. If there is a bent portion in the region close to the antenna shaft 9, there is a risk of discharge. Therefore, a region G having a substantially triangular opening shape is formed in the region close to the antenna shaft 9 to eliminate the sharp portion.

Further, at the formation position of the third microwave emission port 19, the straight line (second position defining line F) connecting the rotation center P of the antenna shaft 9 and the intersection D having a substantially cross opening shape is a rectangular region 16 and a second arc. It is a position that serves as a center line that divides the region 15 into substantially the same area. In the substantially cross opening shape of the third microwave emission port 19, the end portion and the bent portion are all formed of curved surfaces in order to prevent electric discharge. The specific opening shape of the third microwave emission port 19 in the first embodiment is, for example, that the length of the elongated opening in the longitudinal direction is 45 mm and the width of the elongated opening is 10 mm. These numbers are examples and do not specify the present invention to these numbers.

As described above, the flat plate antenna 7 in the first embodiment forms a flat surface (antenna surface) A that radiates microwaves from a single substantially flat plate material, and its rotation center P (flat surface A). The antenna shaft 9 is provided on the back surface of the tablet. Therefore, the flat plate antenna 7 of the first embodiment does not have a waveguide structure, and has a configuration different from the configuration in which microwaves are transmitted and radiated in a predetermined direction by the waveguide structure. Therefore, the flat-plate antenna 7 radiates microwaves in all directions in the horizontal direction from the outer peripheral portion of the flat-plate antenna 7 while rotating, and a plurality of openings (first microwave emission ports) formed on the flat surface A. 17, the second microwave emission port 18, and the third microwave emission port 19) radiate circularly polarized waves and linearly polarized waves.

FIG. 7 shows the results obtained by the analysis by the inventors with respect to the flat plate antenna 7 having the configuration of the first embodiment. FIG. 7A shows a broken line of the electric field vector locus of the microwave radiated from the first microwave emission port 17, the second microwave emission port 18, and the third microwave emission port 19 in the flat antenna 7. It is a figure shown by. FIG. 7B is a contour diagram showing the electric field strength of the flat antenna 7. In the contour diagram of FIG. 7B, a dark-colored region in the central region indicates a region with a strong electric field strength. The contour diagram used here is a color diagram, in which the dark region in the central region is red, the dark portion in the outer region is blue, and the electric field strength is low. Similarly, in the contour diagram described below, the dark-colored region in the central region indicates the region where the electric field strength is strong.

As shown in FIG. 7A, elliptically polarized microwaves having an elliptical circularly polarized electric field vector locus are emitted from the first microwave emission port 17 and the second microwave emission port 18. ing. On the other hand, linearly polarized microwaves are emitted from the third microwave emission port 19. The linearly polarized light radiated from the third microwave emission port 19 is on the substantially line connecting the rotation center P and the substantially cross-opening intersection D of the third microwave emission port 19 on the flat surface A of the flat antenna 7. Is the linearly polarized wave that is the locus of the electric field vector.

The reason why circularly polarized light is radiated from the first microwave emission port 17 and the second microwave emission port 18 is that the direction of the current flowing through the flat surface (antenna surface) A of the flat antenna 7 is the direction of the microwave emission port. This is probably because the flow does not occur symmetrically in both sides of the opening. That is, the intersection (B or C) of the first microwave emission port 17 or the second microwave emission port 18 is connected to the waveguide 6 and the rotation center P of the antenna shaft 9 which is coupled so as to be capable of microwave transmission. It is considered that the outer region divided by the line (first position defining line E) does not have a symmetrical shape. Regarding the third microwave emission port 19, the outer region divided into two by the line (second position defining line F) connecting the opening-shaped intersection D and the rotation center P of the antenna shaft 9 is symmetrical.

As shown in the contour diagram of FIG. 7B, the electric field strength is strong at the first microwave emission port 17, the second microwave emission port 18, and the third microwave emission port 19, and the flat antenna 7 The electric field strength is also strong in the outer peripheral part of the antenna, and microwaves with a large output are radiated.

FIG. 8 is a plan view showing a modified example of the flat plate antenna 7 according to the first embodiment. The flat antenna 7A shown in FIG. 8 differs from the flat antenna 7 shown in FIG. 6 in the opening shape of the third microwave emission port 19A, and other configurations are the same. As shown in FIG. 8, the third microwave emission port 19A has a cross opening shape in which elongated openings of the same length are orthogonal to each other. That is, the cross opening shape of the third microwave emission port 19A shown in FIG. 8 is a cross opening shape that does not include the substantially triangular opening shape (G) as shown in FIG. In this way, as shown in the flat antenna (7,7A), the opening shape of the microwave oven can be changed to a cross opening shape or a substantially triangular opening shape (opening of region G) according to the specifications of the microwave oven. ) Can be configured into a substantially cross opening shape. That is, in a device having a large heating output and heating capacity, in order to more reliably prevent the generation of discharge, the edge of the microwave emission port in the region near the antenna shaft 9 does not have an acute-angled portion, for example. It is possible to configure it as an opening shape that removes acute-angled parts so as to include a substantially triangular opening shape (opening of region G), and conversely, in a device with a small heating output and heating capacity, it can be configured as a simple cross opening shape. is there.

As described above, in the microwave oven which is the microwave heating device of the first embodiment, it has a flat plate shape composed of a flat plate having a flat antenna surface (A) that radiates microwaves of circularly polarized waves and linearly polarized waves. Due to the antenna, even if the capacity of the heating chamber is small and the heating output is small, it retains the high functionality of being able to heat the object to be heated in the heating chamber substantially uniformly, and the antenna structure is further enhanced. Since it is simple and small, the device as a whole can be miniaturized and the price can be reduced. Further, in the microwave oven of the first embodiment, since the antenna structure is simplified, it is possible to provide a highly reliable microwave oven with few failures.

<< Embodiment 2 >>
Hereinafter, the microwave heating device of the second embodiment will be described focusing on the differences from the first embodiment. In the description of the second embodiment, the same reference numerals are given to the components having the same functions as those of the first embodiment, and the description thereof will be omitted. Further, the description of the content having the same function as that of the first embodiment may be omitted in order to avoid duplicate description.

The microwave oven, which is the microwave heating device of the second embodiment, differs from the microwave oven of the first embodiment in the shape of the flat antenna, and in particular, the opening shape is different. FIG. 9 is a plan view showing a flat surface (antenna surface) A of the flat plate antenna 7B in the microwave oven of the second embodiment.

The first microwave emission port 17B and the second microwave emission port 18B in the second embodiment are the second positions connecting the opening-shaped intersection D of the third microwave emission port 19B and the rotation center P of the antenna shaft 9. It is arranged line-symmetrically with respect to the defined line F and has the same opening shape. Each of the first microwave emission port 17B and the second microwave emission port 18B has a cross opening shape (substantially X-shaped) in which elongated openings (first opening 20B and second opening 21B) having different lengths intersect. Is. The position of the intersection (B, C) of each cross opening shape is the same as the position of the intersection (B, C) on the flat surface (antenna surface) A of the flat plate antenna 7 in the above-described first embodiment.

In the cross-opening shape (substantially X-shaped) of the first microwave emission port 17B, the center line J extending in the longitudinal direction of the first opening 20B connects the rotation center P of the antenna shaft 9 and the intersection B of the cross-opening shape. It forms an angle of 45 degrees with respect to the first position defining line E to be connected. On the other hand, the center line K extending in the longitudinal direction of the second opening 21B forms an angle of 25 degrees with respect to the first position defining line E. That is, at the intersection angle of the longitudinal center lines (J, K) of the two elongated openings constituting the first microwave emission port 17B, the angle of the region facing the center of rotation is narrower than 90 degrees (70). Degree).

Similarly, in the cross opening shape of the second microwave emission port 18B, the center line J extending in the longitudinal direction of the first opening 20B forms an angle of 45 degrees with respect to the first position defining line E. On the other hand, the center line K extending in the longitudinal direction of the second opening 21B in the second microwave emission port 18B forms an angle of 25 degrees with respect to the first position defining line E. The cross opening shape of the first microwave emission port 17B and the second microwave emission port 18B has a curved end and a bent portion in order to prevent electric discharge.

The first microwave emission port 17B and the second microwave emission port 18B are formed in the first arc regions 14 and 14, respectively, as in the configuration of the first embodiment. Further, the intersections (B, C) of the cross-opening shapes of the first microwave emission port 17B and the second microwave emission port 18B exist on the first position defining line E, and the first position defining line E Is the center line that divides the first arc regions 14, 14 into substantially the same area.

The specific cross-opening shape of the first microwave emission port 17B and the second microwave emission port 18B in the second embodiment has a length of the first opening 20B in the longitudinal direction, for example, 50 mm. The length of the two openings 21A in the longitudinal direction is, for example, 35 mm. That is, the length of the first opening 20B in the longitudinal direction is 32.5 mm from each intersection (B or C) of the cross opening shape in the direction in which the second position defining line F exists, and each intersection. It has a length of 17.5 mm in the opposite direction from (B or C). The width of the first opening 20B and the second opening 21B is, for example, 10 mm.

The third microwave emission port 19B in the second embodiment has the same shape as the third microwave emission port 19 in the first embodiment described above, and is formed in the rectangular region 16 of the flat plate antenna 7B. The specific opening shape of the third microwave emission port 19B in the second embodiment is, for example, that the length of the elongated opening in the longitudinal direction is 45 mm and the width of the elongated opening is 10 mm. The above specific numerical values are examples, and the present invention is not specified in these numerical values.

As described above, in the flat plate antenna 7B according to the second embodiment, a flat surface (antenna surface) A that radiates microwaves is formed by a single substantially flat plate material, and the antenna shaft 9 is placed at the center of rotation thereof. It is a provided configuration. Therefore, the flat plate antenna 7B of the second embodiment does not have a waveguide structure, and has a configuration different from the configuration in which microwaves are transmitted and radiated in a predetermined direction by the waveguide structure. Therefore, the flat-plate antenna 7B according to the second embodiment radiates microwaves in all directions in the horizontal direction from the outer peripheral portion of the flat-plate antenna 7A while rotating, and has a plurality of openings (the first) formed on the flat surface A. It is configured to radiate circularly polarized waves and linearly polarized waves from 1 microwave emission port 17B, 2nd microwave emission port 18B, and 3rd microwave emission port 19B).

FIG. 10 shows the results obtained by the analysis by the inventors with respect to the flat antenna 7B having the configuration of the second embodiment. FIG. 10A shows a broken line of the trajectory of the electric field vector of the microwave radiated from the first microwave emission port 17B, the second microwave emission port 18B, and the third microwave emission port 19B in the flat antenna 7B. It is a figure shown by. FIG. 10B shows a contour diagram of the electric field strength radiated from the flat antenna 7B.

As shown in FIG. 10A, microwaves having an elliptically polarized locus of the electric field vector are emitted from the first microwave emission port 17B and the second microwave emission port 18B. The electric field vector locus is elliptically polarized with a diameter larger than that of the elliptically polarized light radiated from the first microwave emission port 17 and the second microwave emission port 18 in the first embodiment. A linearly polarized microwave is emitted from the third microwave emission port 19A. Since the microwave emitted from the third microwave emission port 19A is linearly polarized, the locus of the electric field vector is substantially on a straight line.

As shown in the contour diagram of FIG. 10B, the electric field strength is strong at the first microwave emission port 17B, the second microwave emission port 18B, and the third microwave emission port 19B, and the flat antenna 7B. Microwaves with strong electric field strength are also radiated from the outer peripheral part of the antenna.

As described above, in the microwave oven which is the microwave heating device of the second embodiment, the heating chamber is provided by a flat antenna having a flat antenna surface (A) that radiates microwaves of circularly polarized waves and linearly polarized waves. Even if the capacity of the antenna is small and the heating output is small, it retains the high functionality of being able to heat the object to be heated in the heating chamber substantially uniformly, and because the antenna structure is simple and small. The size of the device as a whole can be reduced, and the price can be reduced. Further, in the microwave oven of the second embodiment, since the antenna structure is simplified, it is possible to provide a highly reliable microwave heating device with few failures.

<< Embodiment 3 >>
Hereinafter, the microwave heating device of the third embodiment will be described focusing on the differences between the first embodiment and the second embodiment. In the description of the third embodiment, the same reference numerals will be given to the components having the same functions as those of the first and second embodiments described above, and the description thereof will be omitted. Further, the description of the content having the same function as that of the first and second embodiments described above may be omitted in order to avoid duplicate description.

The microwave oven, which is the microwave heating device of the third embodiment, differs from the microwave ovens of the first and second embodiments in the shape of the flat antenna, and in particular, the outer shape and the opening shape are different. FIG. 11 is a plan view showing a flat surface (antenna surface) A of the flat plate antenna 7B in the microwave oven of the third embodiment.

The first microwave emission port 17C and the second microwave emission port 18C in the third embodiment are the second positions connecting the opening-shaped intersection D of the third microwave emission port 19C and the rotation center P of the antenna shaft 9. It is arranged line-symmetrically with respect to the defined line F and has the same opening shape. Each of the first microwave emission port 17C and the second microwave emission port 18C has a cross opening shape (substantially X-shaped) in which elongated openings (first opening 20C and second opening 21C) having different lengths are orthogonal to each other. Is. The position of the intersection (B, C) of each cross opening shape is the same as the position of the intersection (B, C) on the flat surface (antenna surface) A of the flat plate antenna 7 in the above-described first embodiment.

In the cross opening shape (substantially X-shaped) of the first microwave emission port 17C, the center line J extending in the longitudinal direction of the first opening 20C forms an angle of 45 degrees with respect to the first position defining line E. ing. Further, the center line K extending in the longitudinal direction of the second opening 21C forms an angle of 45 degrees with respect to the first position defining line E.

Similarly, in the cross opening shape of the second microwave emission port 18C, the center line J extending in the longitudinal direction of the first opening 20C forms an angle of 45 degrees with respect to the first position defining line E. The center line K extending in the longitudinal direction of the second opening 21C in the second microwave emission port 18C forms an angle of 45 degrees with respect to the first position defining line E.

The opening shapes of the first microwave emission port 17C and the second microwave emission port 18C in the third embodiment are the same, but the central positions in the longitudinal direction in the first opening 20C and the second opening 21C, respectively. No intersections (B, C) are located at. That is, in the first opening 20C, the opening region extending from the intersection B in the direction of the second position defining line F is formed longer than the opening region extending in the opposite direction from the intersection B. Similarly, in the second opening 21C, the opening region extending from the intersection B in the direction of the second position defining line F is formed longer than the opening region extending in the opposite direction from the intersection B.

The specific cross-opening shape of the first microwave emission port 17C and the second microwave emission port 18C in the third embodiment has a length of the first opening 20C in the longitudinal direction, for example, 50.0 mm. The length of the two openings 21C in the longitudinal direction is, for example, 42.5 mm. That is, the length of the first opening 20C in the longitudinal direction is 32.5 mm in the direction of the second position defining line F from each intersection (B or C) of the cross opening shape, and each intersection (B). Or it has a length of 17.5 mm in the opposite direction from C). On the other hand, the length of the second opening 21C in the longitudinal direction is 25.0 mm in the direction of the second position defining line F from each intersection (B or C) of the cross opening shape, and each intersection (B). Or it has a length of 17.5 mm in the opposite direction from C). The width of the first opening 20C and the second opening 21C is, for example, 10 mm. These numbers are examples and do not specify the present invention to these numbers. The cross opening shape of the first microwave emission port 17C and the second microwave emission port 18C has a curved end and a bent portion in order to prevent electric discharge.

The third microwave emission port 19C in the third embodiment has the same shape as the third microwave emission port 19 (FIG. 5) in the first embodiment described above, and is formed in the rectangular region 16C of the flat antenna 7C. There is. The specific opening shape of the third microwave emission port 19C in the third embodiment is, for example, that the length of the elongated opening in the longitudinal direction is 45 mm and the width of the elongated opening is 10 mm. These numbers are examples and do not specify the present invention to these numbers. In the first microwave emission port 17C, the second microwave emission port 18C, and / or the third microwave emission port 19C in the third embodiment, the third microwave emission port of FIG. 6 shown as a modification is shown. In a region close to the antenna shaft 9 as in 19A, an opening such as a substantially triangular shape (opening in region G) may be formed to eliminate a sharp portion and further prevent the risk of discharge generation. ..

In the microwave oven of the third embodiment, the plan view shape (antenna surface shape) of the flat plate antenna 7C is different from the plan view shape of the flat plate antenna 7 in the first embodiment. As shown in FIG. 11, in the flat antenna 7C according to the third embodiment, the first arc region 14 and the second arc region 15 have the same radius, and one arc region 22 is formed. .. That is, in the configuration of the third embodiment, the flat surface (antenna surface) of the flat plate antenna 7C is composed of the arc region 22 and the rectangular region 16, and the central angle of the arc region 22 is about 260 degrees. There is.

The first microwave emission port 17C and the second microwave emission port 18C in the third embodiment are formed in the arc region 22 so as to face each other with the rotation center P in between. The intersections (B, C) of the first microwave emission port 17C and the second microwave emission port 18C each having a cross opening shape exist on the first position defining line E.

As described above, the flat plate antenna 7C according to the third embodiment forms a flat surface (antenna surface) A that radiates microwaves from a single substantially flat plate material, and the antenna shaft 9 is located at the center of rotation P thereof. It is a configuration provided with. Therefore, the flat plate antenna 7C of the third embodiment does not have a waveguide structure, and has a configuration different from the configuration in which microwaves are transmitted and radiated in a predetermined direction by the waveguide structure. Therefore, the flat-plate antenna 7C according to the third embodiment radiates microwaves in all directions in the horizontal direction from the outer peripheral portion of the flat-plate antenna 7C while rotating, and has a plurality of openings (the first) formed on the flat surface A. It is configured to radiate circularly polarized waves and linearly polarized waves from 1 microwave emission port 17C, 2nd microwave emission port 18C, and 3rd microwave emission port 19C).

FIG. 12 shows the results obtained by the analysis by the inventors with respect to the flat antenna 7C having the configuration of the third embodiment. FIG. 12A shows a broken line of the trajectory of the electric field vector of the microwave radiated from the first microwave emission port 17C, the second microwave emission port 18C, and the third microwave emission port 19C in the flat antenna 7C. It is a figure shown by. FIG. 12B shows a contour diagram of the electric field strength in the flat antenna 7C.

As shown in FIG. 12A, microwaves having an elliptically polarized locus of the electric field vector are emitted from the first microwave emission port 17C and the second microwave emission port 18C. The locus of the electric field vector is closer to a perfect circle than the elliptically polarized light radiated from the first microwave emission port 17 and the second microwave emission port 18 in the first embodiment. A linearly polarized microwave is emitted from the third microwave emission port 19C.

As shown in the contour diagram of FIG. 12B, the electric field strength is strong at the first microwave emission port 17C, the second microwave emission port 18C, and the third microwave emission port 19C, and the flat antenna 7C. The electric field strength is also strong in the outer peripheral part of the antenna, and microwaves with a large output are radiated.

As described above, in the microwave oven which is the microwave heating device of the third embodiment, the heating chamber is provided by a flat antenna having a flat antenna surface (A) that radiates microwaves of circularly polarized waves and linearly polarized waves. Even if the capacity of the antenna is small and the heating output is small, it retains the high functionality of being able to heat the object to be heated in the heating chamber substantially uniformly, and because the antenna structure is simple and small. The size of the device as a whole can be reduced, and the price can be reduced. Further, in the microwave oven of the third embodiment, since the antenna structure is simplified, it is possible to provide a highly reliable microwave heating device with few failures.

<< Embodiment 4 >>
Hereinafter, the microwave heating device of the fourth embodiment will be described focusing on the differences from the first to the third embodiments. In the description of the fourth embodiment, the same reference numerals are given to the components having the same functions as those of the first to third embodiments described above, and the description thereof will be omitted. In addition, the description of the contents having the same functions as those of the above-described first to third embodiments may be omitted in order to avoid duplicate description.

The microwave oven, which is the microwave heating device of the fourth embodiment, differs from the microwave ovens of the first to third embodiments in the shape of the flat antenna, and in particular, the outer shape and the opening shape are different. FIG. 13 shows the flat surface (antenna surface) A of the flat plate antenna 7D in the microwave oven of the fourth embodiment, and also shows the analysis result regarding the flat surface antenna 7D. FIG. 13A is a diagram showing the shape of the flat-plate antenna 7D and the locus of the electric field vector of the microwave radiated from the microwave emission port 23 in the flat-plate antenna 7D by broken lines. FIG. 13B shows a contour diagram of the electric field strength in the flat antenna 7D.

As shown in FIG. 13A, the plan view (antenna surface) of the flat plate antenna 7D in the fourth embodiment is a disk shape. Further, in the configuration of the fourth embodiment, one microwave emission port 23 is formed on the antenna surface (A). As shown in the first to third embodiments described above, the microwave emission port 23 is a cross opening in which two elongated openings (first opening 20D and second opening 21D) having different lengths are orthogonal to each other. The shape (substantially X-shaped).

In the cross-opening shape (substantially X-shaped) of the microwave emission port 23, the center line J extending in the longitudinal direction of the first opening 20D connects the rotation center P of the antenna shaft 9 and the intersection M of the cross-opening shape. It forms an angle of 45 degrees with respect to the 1-position defining line E. Similarly, the center line K extending in the longitudinal direction of the second opening 21D forms an angle of 45 degrees with respect to the first position defining line E.

Further, the length of the first opening 20D in the longitudinal direction is formed longer than the length of the second opening 21D in the longitudinal direction. Specifically, in the configuration of the fourth embodiment, the length of the first opening 20D in the longitudinal direction is 110.78 mm, and the length of the second opening 21D in the longitudinal direction is 51.55 mm. The ratio of the length of the second opening 21D / the first opening 20D was about 46.5%.

The microwave emission port 23 is formed at a position eccentric from the rotation center P of the antenna surface (A) of the flat antenna 7D, and the intersection M is located at a position of 1/3 of the radius of the circular antenna surface (A). It is set. The outer diameter of the flat plate antenna 7D in the fourth embodiment is 120 mm, which is about one wavelength of the frequency (2.45 GHz) used in the microwave oven.

As shown in FIG. 13 (a), a circularly polarized microwave having a substantially circular electric field vector locus is radiated from the microwave emission port 23 of the flat antenna 7D in the fourth embodiment. As shown in the contour diagram of FIG. 13B, the electric field strength is strong in the vicinity of the microwave emission port 23 and also in the outer peripheral portion of the flat plate antenna 7D, and a microwave having a large output is emitted. ..

14 and 15 show a modified example of the configuration of the disc-shaped flat plate antenna (7E, 7F) in the fourth embodiment. FIG. 14 shows the flat surface (antenna surface) A of the flat plate antenna 7E and shows the analysis result of the flat surface antenna 7E. FIG. 15 shows the flat surface (antenna surface) A of the flat plate antenna 7F and shows the analysis results of the flat antenna 7F.

In the plan view (antenna surface) of the disc-shaped flat plate antenna 7E shown in FIG. 14A, one microwave emission port 24 is formed on the antenna surface. The cross-opening shape (substantially X-shaped) of the microwave emitting port 24 differs from the microwave emitting port 23 shown in FIG. 13 in the longitudinal direction of the first opening 20E and the second opening 21E, respectively. The length. The specific length of the microwave emission port 24 in the flat antenna 7E is 98.37 mm in the longitudinal direction of the first opening 20E and 57. in the longitudinal direction of the second opening 21E. It is 9 mm. The ratio of the length of the second opening 21E / the first opening 20E was about 58.9%.

Similar to the microwave emission port 23 shown in FIG. 13, the microwave emission port 24 is also formed at a position eccentric from the rotation center P of the antenna surface (A) of the flat antenna 7E, and has a circular antenna surface. The intersection M is set at a position of 1/3 of the radius in (A). Further, as a specific outer diameter dimension of the flat plate antenna 7E, one having a diameter of 120 mm was used.

As shown in FIG. 14A, microwaves having an elliptically polarized locus of the electric field vector are radiated from the microwave emission port 24 of the flat antenna 7E. As shown in the contour diagram of FIG. 14B, the electric field strength is strong in the vicinity of the microwave emission port 24 and also in the outer peripheral portion of the flat plate antenna 7E, and a microwave having a large output is emitted. ..

In the plan view (antenna surface) of the disc-shaped flat plate antenna 7F shown in FIG. 15A, one microwave emission port 25 is formed on the antenna surface. In the cross opening shape (substantially X-shaped) of the microwave emission port 25, the length of the first opening 20F in the longitudinal direction is 84.04 mm, and the length of the second opening 21F in the longitudinal direction is 67. It is 2 mm. The ratio of the length of the second opening 21F / the first opening 20F was about 80%.

Similar to the microwave emission port 23 shown in FIG. 13, the microwave emission port 25 is also formed at a position eccentric from the rotation center P of the antenna surface (A) of the flat antenna 7E, and has a circular antenna surface. The intersection M is set at a position of 1/3 of the radius in (A). Further, as a specific outer diameter dimension of the flat plate antenna 7F, one having a diameter of 120 mm was used.

As shown in FIG. 15A, microwaves having an elliptically polarized locus of the electric field vector are radiated from the microwave emission port 25 of the flat antenna 7F. As shown in the contour diagram of FIG. 15B, the electric field strength is strong in the vicinity of the microwave emission port 25 and also in the outer peripheral portion of the flat plate antenna 7F, and a microwave having a large output is radiated. ..

As described above, in the configuration of the microwave oven of the fourth embodiment, a flat antenna (7D, 7E, 7F) whose antenna surface (A) is a circular flat plate is used, and a specific position of the antenna surface (A) is used. By forming a microwave emission port having a substantially cross opening shape by intersecting two elongated openings having different lengths, the electric field distribution on the antenna surface (A) becomes unbalanced, and circularly polarized light is generated from the microwave emission port. It is configured to be radiated.

According to the results analyzed by the inventors, when the disc-shaped antenna surface (A) is used, the ratio of the lengths in the longitudinal direction between the first opening and the second opening having a substantially cross-opening shape (the first). It can be understood that the desired circularly polarized light is formed by setting (2 openings / 1st opening) within the range of 50 to 80%, which contributes to uniform heating in the heating chamber.

As described above, in the microwave oven which is the microwave heating device of the fourth embodiment, a disk-shaped flat antenna having a flat antenna surface (A) for radiating circularly polarized microwaves is used in the heating chamber. Even if the capacity is small and the heating output is small, it retains the high functionality of being able to heat the object to be heated in the heating chamber substantially uniformly, and because the antenna structure is simple and small, the device As a whole, miniaturization can be achieved and price reduction can be achieved. Further, in the microwave oven of the fourth embodiment, since the antenna structure is simplified, it is possible to provide a highly reliable microwave heating device with few failures.

As described above, in the microwave heating device of the present invention, as specifically described with reference to each embodiment and modification, it is possible to accommodate a small number of households due to changes in lifestyle. It is possible to provide products with high functionality, miniaturization, low price, and high reliability while maintaining high functionality, and it is possible to provide a microwave heating device with a highly reliable configuration. Become.

The present invention can provide the market with a microwave heating device that is compact, inexpensive, and highly reliable while maintaining high functionality while having a small capacity for a small number of households. It is a useful invention.

1 Main body of microwave oven 2 Heating chamber 3 Door 3a Handle 4 Operation part 5 Magnetron (microwave forming part)
6 Waveguide 6d Antenna holder 7 Flat antenna 8 Antenna motor 9 Antenna shaft 10 Microwave radiation unit 11 Rotating shaft 12 Antenna receiver 13 Power supply chamber 14 1st arc region 15 2nd arc region 16 Rectangular region 17 1st microwave Radiation port 18 2nd microwave emission port 19 3rd microwave emission port 20 1st opening 21 2nd opening 22 Arc region 23 Microwave emission port 24 Microwave emission port 25 Microwave emission port A Flat surface B 1st Intersection of microwave emission port C Intersection of second microwave emission port D Intersection of third microwave emission port E First position regulation line F Second position regulation line

Claims (10)

A heating chamber with a flat bottom surface on which the object to be heated is placed,
A power supply chamber formed under the bottom surface of the heating chamber,
A flat antenna provided inside the power supply chamber and having an antenna surface that rotates in the same horizontal plane,
It is provided with a waveguide coupled so as to be capable of microwave transmission via an antenna shaft provided at the center of rotation of the flat plate antenna, and a microwave forming unit for forming microwaves transmitted to the waveguide. It is a microwave heating device
The antenna surface of the flat antenna has at least one microwave emission port including an aperture shape in which two elongated openings intersect.
Each of the longitudinal centerlines of the two elongated openings constituting the at least one microwave emission port connects the rotation center of the flat antenna and the intersection in the shape where the two elongated openings intersect. an angle to position defining line extending,
The antenna surface is divided into a plurality of regions by a line extending radially from the center of rotation, and the adjacent regions in the divided regions are formed of the same plane having a different plan view shape.
In the divided region, at least one microwave emission port is provided in each of the regions facing each other with the rotation center in between.
A microwave heating device configured to radiate circularly polarized waves from at least one microwave emission port in a direction directly above the antenna surface. A heating chamber with a flat bottom surface on which the object to be heated is placed,
A power supply chamber formed under the bottom surface of the heating chamber,
A flat antenna provided inside the power supply chamber and having an antenna surface that rotates in the same horizontal plane,
A waveguide coupled so as to be capable of microwave transmission via an antenna shaft provided at the center of rotation of the flat plate antenna, and
A microwave heating device including a microwave forming unit for forming microwaves transmitted to the waveguide.
The antenna surface of the flat antenna has at least one microwave emission port including an aperture shape in which two elongated openings intersect.
Each of the longitudinal centerlines of the two elongated openings constituting the at least one microwave emission port connects the rotation center of the flat antenna and the intersection in the shape where the two elongated openings intersect. Has an angle with respect to the position defining line extending to
The antenna surface is divided into a plurality of regions by a line extending radially from the center of rotation, and the adjacent regions in the divided regions are formed of the same plane having a different plan view shape.
The antenna surface is divided into four regions, two first arc regions, a second arc region having a smaller radius than each of the first arc regions, and a rectangular region by a line extending radially from the center of rotation. The second arc region and the rectangular region are arranged on both sides of the first arc region, and at least one microwave emission port is provided in each of the two first arc regions. ,
A microwave heating device configured to radiate circularly polarized waves from at least one microwave emission port in a direction directly above the antenna surface. A heating chamber with a flat bottom surface on which the object to be heated is placed,
A power supply chamber formed under the bottom surface of the heating chamber,
A flat antenna provided inside the power supply chamber and having an antenna surface that rotates in the same horizontal plane,
A waveguide coupled so as to be capable of microwave transmission via an antenna shaft provided at the center of rotation of the flat plate antenna, and
A microwave heating device including a microwave forming unit for forming microwaves transmitted to the waveguide.
The antenna surface of the flat antenna has at least one microwave emission port including an aperture shape in which two elongated openings intersect.
Each of the longitudinal centerlines of the two elongated openings constituting the at least one microwave emission port connects the rotation center of the flat antenna and the intersection in the shape where the two elongated openings intersect. Has an angle with respect to the position defining line extending to
The antenna surface is divided into a plurality of regions by a line extending radially from the center of rotation, and the adjacent regions in the divided regions are formed of the same plane having a different plan view shape.
The antenna surface is divided into an arc region and a rectangular region by a line extending radially from the rotation center, and at least one microwave emission port is provided in the arc region.
The two elongated openings constituting the at least one microwave emission port are configured to have different lengths in the longitudinal direction.
A microwave heating device configured to radiate circularly polarized waves from at least one microwave emission port in a direction directly above the antenna surface. The microwave heating device according to any one of claims 1 to 3, wherein the at least one microwave emission port is provided in at least one region in the divided region. At the intersection angle of the longitudinal center lines of the two elongated openings constituting the at least one microwave emission port, the angle of the region facing the center of rotation is configured to have an angle narrower than 90 degrees. The microwave heating device according to any one of claims 1 to 4. Microwave radiation port longitudinal length of the two elongated openings is the same provided in the rectangular region, the microwave heating apparatus according to claim 2. The microwave heating device according to any one of claims 1 to 6 , wherein the two elongated openings constituting the at least one microwave emission port are configured to have different lengths in the longitudinal direction. A heating chamber with a flat bottom surface on which the object to be heated is placed,
A power supply chamber formed under the bottom surface of the heating chamber,
A flat antenna provided inside the power supply chamber and having an antenna surface that rotates in the same horizontal plane,
A waveguide coupled so as to be capable of microwave transmission via an antenna shaft provided at the center of rotation of the flat plate antenna, and
A microwave heating device including a microwave forming unit for forming microwaves transmitted to the waveguide.
The antenna surface of the flat antenna has at least one microwave emission port including an aperture shape in which two elongated openings intersect.
Each of the longitudinal centerlines of the two elongated openings constituting the at least one microwave emission port connects the rotation center of the flat antenna and the intersection in the shape where the two elongated openings intersect. Has an angle with respect to the position defining line extending to
The antenna surface has a substantially circular shape in a plan view, and an intersection is arranged at a position where the at least one microwave emission port is eccentric from the rotation center to form the at least one microwave emission port. A microwave heating device configured such that the ratio of the lengths of the two elongated openings in the longitudinal direction is within the range of 50 to 80%. The microwave heating device according to any one of claims 1 to 8, wherein the center lines in the longitudinal direction of the two elongated openings constituting the at least one microwave emission port are orthogonal to each other. Any one of claims 1 to 9 , wherein the microwave emission port including the shape in which the two elongated openings intersect has a configuration in which the edge of the opening facing the antenna shaft does not have an acute-angled portion. The microwave heating device according to the section.

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