Microwave oven

Abstract

To provide a microwave oven capable of improving heating efficiency of an object to be heated and suppressing uneven heating with a simple configuration.SOLUTION: A microwave oven (10) includes: a heating chamber (14); a bottom microwave source (31A) and a rear microwave source (31B) disposed outside the heating chamber (14); a bottom feeding unit (33A) disposed below a bottom wall (15) of the heating chamber (14); a rear feeding unit (33B) disposed behind a rear wall (18) of the heating chamber (14); and a control unit (50) configured to individually control the microwave sources (31A, 31B).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a microwave oven. [Background technology]

[0002] Patent Document 1 discloses a microwave oven in which power supply units for radiating microwaves are arranged on the top wall, bottom wall, and a pair of side walls of a heating chamber. This microwave oven further includes a first antenna and a second antenna having different shapes to adjust the radiation direction of the microwaves radiated from the respective power supply units, and a control unit that adjusts the rotation angle positions of these antennas.

[0003] The first antenna and the second antenna are arranged on opposing walls of the heating chamber. Specifically, the first antenna is arranged between the top wall and one of the pair of side walls, and the second antenna is arranged between the bottom wall and the other of the pair of side walls. The control unit detects reflected microwaves and adjusts the angles of the first antenna and the second antenna so that the reflected power is minimized, thereby improving the heating efficiency of the heated object and suppressing uneven heating. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2009-181727 Summary of the Invention [Problem to be solved by the invention]

[0005] The microwave oven of Patent Document 1 has a complex configuration because it requires antennas to be placed on the top and bottom walls and on each of the pair of side walls. In other words, the microwave oven of Patent Document 1 has room for improvement in terms of improving the heating efficiency of the heated object with a simple configuration and suppressing uneven heating.

[0006] An object of the present invention is to provide a microwave oven that has a simple configuration, improves the heating efficiency of an object to be heated, and suppresses uneven heating. [Means for solving the problem]

[0007] One aspect of the present invention provides a microwave oven comprising: a heating chamber defined by a bottom wall, a top wall, a pair of side walls, a rear wall, and a door; a bottom microwave source and a rear microwave source each arranged outside the heating chamber; a bottom power supply unit arranged below the bottom wall and radiating microwaves emitted by the bottom microwave source through the bottom wall into the heating chamber; a rear power supply unit arranged behind the rear wall and radiating microwaves emitted by the rear microwave source through the rear wall into the heating chamber; and a control unit that individually controls the bottom microwave source and the rear microwave source.

[0008] Microwave ovens are often installed in a dedicated installation space in a kitchen cupboard. The depth of the installation space is generally determined based on the usability of the kitchen in which the cupboard is installed. The height of the installation space is generally determined based on the storage capacity of tableware. On the other hand, the width of the cupboard, including the installation space, can be selected by the user according to their preference, taking into account the size of the kitchen.

[0009] Generally, the depth and height of a microwave oven are determined based on the dimensions of the cupboard space in which it is installed. On the other hand, the width of a microwave oven is determined according to the capacity of the heating chamber it forms; the larger the capacity, the larger the heating chamber becomes, and the longer the shape of the heating chamber becomes. In other words, the depth and height of a microwave oven are fairly constant, while the width of a microwave oven is highly variable. Also, the distance from the bottom wall and the back wall to the heated object placed inside the heating chamber is often closer than the distance from the side walls.

[0010] In this embodiment, power supply units that radiate microwaves are disposed on the bottom wall and the rear wall, respectively. Because the bottom wall and the rear wall are close to the object to be heated, microwaves that tend to diffuse with increasing distance from the power supply units can be concentrated on the object to be heated. This allows for improved heating efficiency of the object to be heated with a simple configuration. Moreover, since the direction of microwave irradiation from the bottom microwave source and the direction of microwave irradiation from the rear microwave source are different and the two microwave sources can be controlled individually by the control unit, uneven heating of the object to be heated can be suppressed.

[0011] The heating chamber includes a tray holding means for placing a tray on which an object to be heated is placed along the bottom wall between the bottom power feeding unit and the rear power feeding unit, and the tray includes at least one of a heat-generating tray capable of generating heat using microwaves, a transparent tray capable of transmitting microwaves, and a reflective tray capable of reflecting microwaves. When a heat-generating tray is used, the heat generated by the microwaves radiated from the bottom power feeding unit heats the object from its lower surface, and the microwaves radiated from the rear power feeding unit heat the object from its interior. This improves the heating efficiency of the object and reduces uneven heating of the object. When a transparent tray is used, the object can be heated by microwaves radiated from the bottom power feeding unit and microwaves radiated from the rear power feeding unit. This improves the heating efficiency of the object and reduces uneven heating of the object. When a reflective tray is used, the microwaves emitted from the bottom power supply unit can heat the objects placed on the bottom wall, and the microwaves emitted from the rear power supply unit can heat the objects placed on the reflective tray. Therefore, different objects can be heated simultaneously and individually, which improves the heating efficiency of the objects and improves user convenience.

[0012] When the heating chamber is viewed from the door side, at least a portion of the rear power supply unit is located above the upper end of the tray, thereby reliably improving the heating efficiency of the objects placed on the tray and reliably suppressing uneven heating of the objects.

[0013] When the heating chamber is viewed from the door side, all of the rear power supply units are located above the upper end of the tray. This improves the heating efficiency of the objects. For example, when a reflective tray is used and objects to be heated are placed on the reflective tray and on the bottom wall, the objects to be heated on the reflective tray can be heated individually by the rear microwave source, and the objects to be heated on the bottom wall can be heated individually by the bottom microwave source, thereby improving the heating efficiency of the objects.

[0014] A first projection area of ​​the bottom power supply unit extending from the bottom wall toward the top wall and a second projection area of ​​the rear power supply unit extending from the rear wall toward the door have an overlapping area, whereby by placing an object to be heated in the overlapping area, it is possible to effectively improve the heating efficiency of the object and effectively suppress uneven heating of the object.

[0015] The overlapping area is located in the center between the pair of side walls and in the center between the rear wall and the door. Because users often place the objects to be heated in the center of the heating chamber, this configuration reliably improves the heating efficiency of the objects to be heated and reliably prevents uneven heating of the objects to be heated.

[0016] A heater is disposed on the top wall. In other words, since the rear power supply unit is disposed on the rear wall instead of the top wall, a heater can be disposed on the top wall. This allows for a composite heating process in which the center of the object to be heated is heated by microwaves from the microwave source, and the outside of the object is heated by radiant heat from the heater. This improves user convenience.

[0017] The control unit repeatedly controls one of the bottom microwave source and the rear microwave source, stopping the other, and then operating the other and stopping the other, at predetermined intervals. Alternatively, the control unit repeatedly controls one of the heating units, including the bottom microwave source, the rear microwave source, and the heater, stopping the remaining, and then operating one other than the one that was operated and stopping the remaining, at predetermined intervals. Here, the microwave source has a limited operating time because it becomes hot when operated continuously. Therefore, for objects that require a relatively long heating time, ensuring a rest period for the microwave source reduces heating efficiency. In contrast, in this embodiment, the multiple heating units, including the bottom microwave source and the rear microwave source, are operated one by one, so that when one heating unit is operated at the maximum available power, the other heating units can be paused. Therefore, since the object to be heated is always heated by one of the multiple heating units, the heating efficiency of the object to be heated can be improved and the total heating time can be shortened compared to when multiple heating units are operated simultaneously. In addition, since the heating directions of the object to be heated by the multiple heating units are different, uneven heating of the object to be heated can be suppressed.

[0018] Alternatively, the control unit may operate the bottom microwave source and the rear microwave source simultaneously. In this way, the power that can be input to each microwave source is lower than when one microwave source is operated, but the entire object to be heated can be heated with so-called low heat, thereby suppressing uneven heating.

[0019] The tray can divide the heating chamber into a lower heating chamber section below the tray and an upper heating chamber section above the tray, and the heating chamber further includes a lower temperature detector that detects the temperature of the objects to be heated in the lower heating chamber and an upper temperature detector that detects the temperature of the objects to be heated in the upper heating chamber. This allows the bottom microwave source and the back microwave source to be controlled according to the heating status of each object to be heated placed in the lower heating chamber and the upper heating chamber, thereby improving the heating efficiency of each object to be heated.

[0020] The control unit controls the bottom microwave source and the back microwave source individually based on the detection results of the lower temperature detection unit and the upper temperature detection unit. For example, the control unit controls the bottom microwave source based on the detection result of the lower temperature detection unit, and controls the back microwave source based on the detection result of the upper temperature detection unit. In this way, the bottom microwave source and the back microwave source are individually controlled according to the heating status of each of the objects to be heated placed in the lower and upper parts of the heating chamber, so that each object to be heated can be reliably heated to a desired state without uneven heating.

[0021] The tray uses a reflective tray, and the lower end of the emission section of the rear microwave source is positioned at a height equal to or higher than the upper end of the reflective tray. This arrangement of the reflective tray can suppress microwave transmission between the lower and upper heating chambers. In other words, the reflective tray effectively divides the interior of the heating chamber into a lower and upper heating chamber. Therefore, the bottom microwave source can reliably heat the objects to be heated in the lower heating chamber, and the rear microwave source can reliably heat the objects to be heated in the upper heating chamber. As a result, a control program for simultaneously and individually heating different objects to be heated placed in the lower and upper heating chambers can be easily constructed.

[0022] A heater is disposed below the bottom wall of the heating chamber, so that the objects placed on the tray in the heating chamber can be heated by radiant heat from the heater, thereby improving the heating efficiency of the objects and improving user convenience. [Effects of the Invention]

[0023] The present invention can improve the heating efficiency of an object to be heated and suppress uneven heating with a simple configuration. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a schematic cross-sectional view of a microwave oven according to a first embodiment of the present invention. [Figure 2]2A to 2C are schematic cross-sectional views of the microwave oven of FIG. 1 cut from different directions. [Figure 3] Figure 1 shows a block diagram of a microwave oven. [Figure 4] 4 is a time chart showing an example of heating control by a control unit. [Figure 5] 10 is a time chart showing another example of heating control by the control unit. [Figure 6] 10 is a time chart showing another example of heating control by the control unit. [Figure 7] FIG. 10 is a schematic cross-sectional view of a microwave oven according to a second embodiment. [Figure 8] 8A and 8B are schematic cross-sectional views of the microwave oven of FIG. 7 cut in different directions. [Figure 9] Block diagram of the microwave oven in Figure 7. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0026] (First embodiment) Figures 1 and 2 show a microwave oven 10 according to a first embodiment of the present invention. The X direction in Figures 1 and 2 is the front-to-rear direction of the microwave oven 10, with the direction indicated by the arrow being the rear side and the direction opposite the arrow being the front side. The Y direction is the width direction of the microwave oven 10, with the direction indicated by the arrow being the left side and the direction opposite the arrow being the right side. The Z direction is the height direction of the microwave oven 10, with the direction indicated by the arrow being the top side and the direction opposite the arrow being the bottom side.

[0027] 1 to 3, microwave oven 10 includes microwave oven body 12, heating compartment 14, door 25, and dedicated trays 40, 41, and 42 that are detachably arranged in heating compartment 14. Microwave oven 10 also includes a plurality of heating sections 31A, 31B, and 38, an infrared sensor 44, a thermistor 45, an operation panel 47, and a control section 50.

[0028] The multiple heating sections include two magnetrons (microwave sources) 31A, 31B and a heater 38. The control section 50 operates either the magnetrons 31A, 31B or the heater 38 in accordance with the heating process selected by operating the operation panel 47, thereby heating the object 1 or 2 to be heated in the heating chamber 14. In this embodiment, the power supply section 33A of the magnetron 31A is disposed below the bottom wall 15 that defines the heating chamber 14, and the power supply section 33B of the magnetron 31B is disposed behind the rear wall 18 that defines the heating chamber 14, thereby improving the heating efficiency of the objects 1 and 2 to be heated and suppressing uneven heating. In this specification, the object 1 to be heated refers to food placed on trays 40-42, and the object 2 to be heated refers to food placed on the bottom wall 15.

[0029] The configuration of microwave oven 10 will be specifically described below.

[0030] 1 and 2, microwave oven body 12 includes heating chamber 14 within housing 13. Heating chamber 14 is a rectangular parallelepiped space defined by bottom wall 15, top wall 16, a pair of side walls 17, a rear wall 18, and door 25, all of which are rectangular. Of these, top wall 16 and a pair of side walls 17 are made of metal plates that reflect microwaves.

[0031] The bottom wall 15 and the rear wall 18 each include a wall main body portion 20 and a radiation portion 21. The wall main body portion 20 is made of a metal plate that is a microwave reflector, and includes a recess 20a that is recessed from the inside of the heating chamber 14 to the outside. The radiation portion 21 is made of a microwave-transmitting material such as ceramic, glass, or resin, and is fitted into the recess 20a. The ratio of the area occupied by the radiation portion 21 to the total area of ​​the bottom wall 15 and the rear wall 18 is more than half (e.g., 80%).

[0032] A pair of guide rails 22, 23 are provided on each of the pair of side walls 17 for arranging trays 40-42 on which the object to be heated 1 is placed. Of these, the lower guide rail 22 is provided in a region of the pair of side walls 17 that is lower than the center of the overall height of the heating chamber 14. The upper guide rail 23 is provided in a region of the pair of side walls 17 that is higher than the center of the overall height of the heating chamber 14. The guide rails 22, 23 are formed by ridges that extend in the front-to-rear direction and cause part of the side wall 17 to protrude into the heating chamber 14. The number of guide rails is not limited to two, and three or more sets may be provided.

[0033] Of the upper and lower guide rails 22, 23, the pair of lower guide rails 22 constitutes the tray holding means of the present invention that positions the trays 40-42 along the bottom wall 15 between the bottom power feeding section 33A (more specifically, the bottom wall 15) and the rear power feeding section 33B within the heating chamber 14. However, the tray holding means is not limited to the guide rails 22, and may be a stand with legs that are separate from or integral with the trays 40-42, as long as it is configured to be able to position the trays 40-42 above the bottom wall 15 with a gap therebetween.

[0034] Door 25 is attached to the front side of housing 13 and releasably closes the front end opening of heating chamber 14. Door 25 is attached to the lower part of housing 13 and is rotatable around a rotation shaft (not shown) extending in the width direction. However, door 25 may also be rotatable around a rotation shaft extending in the height direction, as long as it is configured to be able to open and close the opening of heating chamber 14.

[0035] Door 25 comprises a door body 26 that does not allow the interior of heating chamber 14 to be seen through, and a window portion 27 that allows the interior of heating chamber 14 to be seen through. Door body 26 is made of a metal plate that is an opaque microwave reflector. Window portion 27 is made of glass or resin that is a transparent microwave transmissive material. Window portion 27 is provided with a reflective layer 28 that can reflect microwaves. Reflective layer 28 is made of punched metal with a large number of holes to ensure visibility.

[0036] The bottom magnetron 31A is a heating unit that radiates microwaves into the heating chamber 14 through the bottom wall 15 to heat the objects 1 and 2. The rear magnetron 31B is a heating unit that radiates microwaves into the heating chamber 14 through the rear wall 18 to heat the objects 1 and 2. These magnetrons 31A and 31B are each disposed below the heating chamber 14 between the housing 13 and the heating chamber 14 outside the heating chamber 14, and are connected to the control unit 50 (see FIG. 3).

[0037] More specifically, the individual magnetrons 31A and 31B radiate microwaves into the heating chamber 14 via waveguides 32A and 32B, power feeders 33A and 33B, and antennas 36A and 36B, respectively. In the following description, the magnetrons 31A and 31B, waveguides 32A and 32B, power feeders 33A and 33B, and antennas 36A and 36B will sometimes be simply referred to as magnetron 31, waveguide 32, power feeder 33, and antenna 36 without distinguishing between bottom and rear magnetrons.

[0038] The waveguide 32 is made of a metal plate that is a microwave reflector. The bottom waveguide 32A used for the bottom magnetron 31A is located below the recess 20a in the bottom wall 15 and extends from the left side of the recess 20a beyond the center of the recess 20a. The bottom magnetron 31A is located at the left end of the bottom waveguide 32A. The rear waveguide 32B used for the rear magnetron 31B is located behind the recess 20a in the rear wall 18 and extends from the bottom side of the recess 20a beyond the center of the recess 20a. The rear magnetron 31B is located at the lower end of the rear waveguide 32B. However, the location of the waveguides 32A and 32B including the magnetrons 31A and 31B can be changed as needed as long as they are located between the inside of the housing 13 and the heating chamber 14.

[0039] The power supply unit 33 is cylindrical and is located at the end of the waveguide 32 opposite the magnetron 31, and is disposed within the recess 20a, penetrating the bottom of the recess 20a. The bottom power supply unit 33A used for the bottom magnetron 31A is disposed in the center of the recess 20a, which is the center in the front-to-rear and width directions of the bottom wall 15. The rear power supply unit 33B used for the rear magnetron 31B is disposed in the center of the recess 20a, which is the center in the width direction and height direction of the rear wall 18.

[0040] To specifically describe the arrangement of rear power feeding unit 33B in the height direction, rear power feeding unit 33B is arranged above the upper ends of trays 40 to 42 when trays 40 to 42 are arranged on guide rails 22. More specifically, in this embodiment, the lower end of rear power feeding unit 33B is configured to be located at the upper ends of trays 40 to 42. However, the arrangement of rear power feeding unit 33B in the height direction only needs to be such that a portion of rear power feeding unit 33B is located above the upper ends of trays 40 to 42.

[0041] As shown by the two-dot chain lines in FIGS. 1 and 2 , a first projection area 34A of bottom power feeding part 33A extending from bottom wall 15 toward top wall 16 and a second projection area 34B of rear power feeding part 33B extending from rear wall 18 toward door 25 include an overlapping area 35. First projection area 34A is defined as an area extending along the axis of bottom power feeding part 33A with the same cross-sectional shape as bottom power feeding part 33A. Second projection area 34B is defined as an area extending along the axis of rear power feeding part 33B with the same cross-sectional shape as rear power feeding part 33B. In this embodiment, the diameter of bottom power feeding part 33A including first projection area 34A and the diameter of rear power feeding part 33B including second projection area 34B are the same, and their axes are perpendicular to each other. However, bottom power feed portion 33A and rear power feed portion 33B may have different diameters, and bottom power feed portion 33A and rear power feed portion 33B may have different cross-sectional shapes. Furthermore, the axis of first projection area 34A and the axis of second projection area 34B may be spaced apart in the width direction of heating chamber 14, as long as overlapping area 35 is formed.

[0042] Here, microwave oven 10 is often installed in a dedicated installation space provided in a kitchen cupboard. The depth of the installation space is generally determined based on the usability of the kitchen in which the cupboard is installed. The height of the installation space is generally determined based on the storage capacity of tableware. On the other hand, the width of the cupboard, including the installation space, can be selected by the user as desired, taking into account the size of the kitchen.

[0043] The depth (front-to-back dimension) and height (height dimension) of microwave oven 10 are determined based on the dimensions of the cupboard installation space. On the other hand, the width of microwave oven 10 is determined according to the capacity of heating chamber 14 to be formed, and increases as the capacity increases, and the shape of heating chamber 14 becomes longer horizontally. In other words, the depth and height of microwave oven 10 are fairly constant, but the width of microwave oven 10 is highly variable. Furthermore, the distances from bottom wall 15 and rear wall 18 to objects to be heated 1, 2 placed in heating chamber 14 are often closer than the distances from side walls 17.

[0044] On the other hand, microwaves radiated from the power feeders 33A and 33B into the heating chamber 14 diffuse as they move away from the power feeders 33A and 33B. In other words, microwaves are more easily irradiated onto the objects 1 and 2 the closer they are to the power feeders 33A and 33B, and more difficult to irradiate onto the objects 1 and 2 the farther they are from the power feeders 33A and 33B. In this embodiment, the power feeders 33A and 33B are disposed on the bottom wall 15 and the rear wall 18, respectively, which are closer to the objects 1 and 2 than they are to the side walls 17. This allows microwaves to be concentrated on the objects 1 and 2, improving the heating efficiency of the objects 1 and 2. Furthermore, because the direction of microwave irradiation by the bottom magnetron 31A and the direction of microwave irradiation by the rear magnetron 31B are different, uneven heating of the objects 1 and 2 can be reduced.

[0045] The antenna 36 is configured to diffuse microwaves radiated from the power supply unit 33 into the heating chamber 14. Each antenna 36 is disk-shaped as in the conventional configuration, and is disposed within each recess 20a between the power supply unit 33 and the radiation unit 21. It is rotatable by a motor 37. A bottom motor 37A, which rotates the bottom antenna 36A disposed above the bottom power supply unit 33A, is disposed below the bottom waveguide 32A. A rear motor 37B, which rotates the rear antenna 36B disposed in front of the rear power supply unit 33B, is disposed behind the rear waveguide 32B. The motor shaft of each motor 36 passes through the waveguide 32 and the power supply unit 33 and protrudes between the power supply unit 33 and the radiation unit 21 within the recess 20a.

[0046] The heater 38 is disposed in a recess 16a of the top wall 16 that recesses from the interior of the heating chamber 14 to the outside, and is a heating unit that heats the object 1 to be heated in the heating chamber 14 by radiant heat. The heater 38 is constituted by a tube heater such as a quartz tube heater, and two heaters 38 are disposed at intervals in the front-to-rear direction, each extending in the width direction, and connected to the control unit 50 (see FIG. 3). However, only one heater 38 may be disposed in the center of the heating chamber 14 in the front-to-rear direction, or three or more heaters 38 may be disposed at intervals in the front-to-rear direction. The heaters 38 may also be disposed so as to extend in the front-to-rear direction. Instead of a tube heater, a mica heater may be disposed on the top surface of the recess 16a (outside the heating chamber 14).

[0047] Trays 40 to 42 are configured to place the object to be heated 1 inside the heating chamber 14, and are selectively and detachably placed on either the lower guide rail 22 or the upper guide rail 23. Alternatively, the same or different trays 40 to 42 may be placed on the lower guide rail 22 and the upper guide rail 23, respectively, and the objects to be heated 1, 1, 2 may be placed in three compartments inside the heating chamber 14. Of the three types of trays, one is a heat-generating tray 40, the other is a transparent tray 41, and the other is a reflective tray 42.

[0048] The heating tray 40 is formed, for example, by welding or adhering ferrite-containing silicone rubber to the underside of an aluminum-plated steel plate, which is a microwave reflector with good thermal conductivity. The transparent tray 41 is formed of a microwave-transmitting material such as ceramic, glass, or resin. The reflective tray 42 is formed of a microwave-reflecting material such as metal. The reflective tray 41 may be formed by providing a reflective layer capable of reflecting microwaves on the surface of a tray body formed of a microwave-transmitting material (for example, ceramic).

[0049] All three types of trays 40 to 42 are rectangular plates when viewed in the height direction, and all have the same shape. However, the shapes of trays 40 to 42 may be different. In this case, it is preferable that rear power feeding unit 33B is disposed in the height direction such that a portion of rear power feeding unit 33B is located above the upper end of either heat-generating tray 40 or reflective tray 42, whichever has the larger height dimension.

[0050] When the heat-generating tray 40 is placed in the heating chamber 14, the heat-generating tray 40 generates heat due to microwaves radiated from the bottom power supply unit 33A, so that the heat from the heat-generating tray 40 heats the lower surface of the object 1 to be heated, and the microwaves radiated from the rear power supply unit 33B heat the object 1 from the inside. For example, when the object 1 to be heated is heated using microwaves, steam generated from the object 1 to be heated (food material) tends to remain below the object 1 to be heated, which tends to result in a poor finish of the lower surface of the object 1 to be heated. In contrast, in this embodiment, the heat-generating tray 40 is used to heat the underside of the object 1 to be heated. Therefore, the finish of the object 1 to be heated can be improved.

[0051] When the transparent tray 41 is placed in the heating chamber 14, the object 1 can be heated by the microwaves radiated from the bottom power feeding unit 33A and the microwaves radiated from the rear power feeding unit 33B. More specifically, the bottom side of the object 1 can be heated by the microwaves radiated from the bottom power feeding unit 33A, and the top side of the object 1 can be heated by the microwaves radiated from the rear power feeding unit 33B. Therefore, similar to the case where the heat-generating tray 40 is used, the finish of the object 1 can be improved.

[0052] When a reflective tray 42 is placed in the heating chamber 14, the object 2 placed on the bottom wall 15 can be heated by microwaves radiated from the bottom power feeder 33A, and the object 1 placed on the reflective tray 42 can be heated by microwaves radiated from the rear power feeder 33B. If the microwave power feeder is provided only on the bottom, when the upper and lower objects 1 and 2 are heated using a transparent tray 41, the heating efficiency of the upper object 1, which is farther from the power feeder, is lower than the heating efficiency of the lower object 2, which is closer to the power feeder. In contrast, in this embodiment, the reflective tray 42 is used, so the lower object 2 can be heated by microwaves radiated from the bottom power feeder 33A, and the upper object 1 can be heated by microwaves radiated from the rear power feeder 33B. Therefore, heating efficiency can be improved when the objects 1 and 2 are placed above and below each other in the heating chamber 14, and the heating of the upper and lower objects 1 and 2 can also be controlled individually.

[0053] 3, the infrared sensor 44 is a temperature detection unit that detects the temperature of the object 2 to be heated, which is arranged on the bottom wall 15 of the heating chamber 14 shown in FIG. 1, and is connected to the control unit 50. For example, the infrared sensor 44 is a monocular thermopile type having one infrared detection element. The infrared sensor 44 is arranged, for example, between the upper guide rail 23 and the top wall 16 shown in FIG. 2, on the outside of the side wall 17, and faces the inside of the heating chamber 14 through a through-hole (not shown) formed in the side wall 17. However, the infrared sensor 44 may also be a multi-lens thermopile type having multiple infrared detection elements. Furthermore, the infrared sensor 44 may be a movable type that can change the detection direction.

[0054] Thermistor 45 is a steam temperature detection unit that detects the temperature of steam inside heating chamber 14 shown in Fig. 1, and is connected to control unit 50. Thermistor 45 is disposed above top wall 16 shown in Fig. 2, with the detection unit being disposed in a corner of heating chamber 14 defined by top wall 16, rear wall 18, and right side wall 17.

[0055] The operation panel 47 includes a liquid crystal panel 48 and an operation unit 49 including switches, and is connected to the control unit 50. The operation panel 47 is located, for example, below the window 27 of the door 25 shown in FIG. 1. The liquid crystal panel 48 displays the selection status of the heating treatment performed by operating the operation unit 49, and the execution status of the heating treatment. The operation unit 49 is, for example, a rotary push switch, and can select any one of multiple types of heating treatment.

[0056] The control unit 50 is composed of one or more microcomputers and other electronic devices. The control unit 50 includes a memory 51 and a timer 52. The memory 51 stores programs for executing a variety of heat treatments, as well as set values ​​(temperatures, times, etc.) used in the programs. The timer 52 measures the execution times of the individual steps of the heat treatments.

[0057] The control unit 50 individually controls the magnetrons 31A, 31B and the heater 38 in accordance with a program determined according to the selected heating treatment, and heats the object 1 or 2. The heating treatments include a microwave heating treatment that controls only the magnetrons 31A, 31B, a composite heating treatment that controls both the magnetrons 31A, 31B and the heater 38, and a heater heating treatment that controls only the heater 38.

[0058] Microwave heating processes include a lower microwave, an upper microwave, and an upper / lower microwave. The lower microwave is performed with the object 2 to be heated placed on the bottom wall 15 of the heating chamber 14. The upper microwave is performed with the object 1 to be heated placed on the heat-generating tray 40 or the transparent tray 41. The upper / lower microwave is performed with the object 2 to be heated placed on the bottom wall 15 and the object 1 to be heated placed on one of the trays 40 to 42. In these microwave heating processes, the control unit 50 controls the magnetrons 31A and 31B based on the detection results of the infrared sensor 44 and the thermistor 45, respectively, to heat the objects 1 and 2 to be heated with microwaves.

[0059] The composite heating process is performed with the object 1 placed on the heat-generating tray 40 or the transparent tray 41. In this composite heating process, the control unit 50 controls the magnetrons 31A, 31B and the heater 38 based only on the detection result of the thermistor 45, and heats the object 1 with microwaves and radiant heat.

[0060] The heater heating process is performed with the object 1 placed on the transparent tray 41 or the reflective tray 42. In this heater heating process, the control unit 50 controls the heater 38 based only on the detection result of the thermistor 45, and heats the object 1 by radiant heat.

[0061] An example of control by the control unit 50 in the microwave heating process and the combined heating process will be specifically described below.

[0062] 4 shows an example of control of the magnetrons 31A and 31B by the control unit 50 during microwave heating. In this example, the control unit 50 repeatedly performs a first step in which the bottom magnetron 31A is activated and the rear magnetron 31B is deactivated, and a second step in which the rear magnetron 31B is activated and the bottom magnetron 31A is deactivated, every set time t. However, it is also possible to operate the rear magnetron 31B in the first step and operate the bottom magnetron 31A in the second step. In other words, the control unit 50 repeatedly performs control in which one of the bottom magnetron 31A and the rear magnetron 31B is activated and the other is deactivated, and then the other is activated and the other is deactivated, every set time t.

[0063] In the control shown in FIG. 4, the power input to one magnetron 31A or 31B is the maximum power that can be input (e.g., 1000 W). The set time t for switching the operation of the magnetrons 31A and 31B is set to a range of 3 to 5 minutes. If the set time t is excessively long, the temperatures of the magnetrons 31A and 31B increase. On the other hand, if the set time t is excessively short, the heating efficiency of the objects 1 and 2 decreases. To prevent these problems, it is preferable to set the set time t for each operation of the magnetrons 31A and 31B within the above-specified range. This configuration improves heating efficiency and shortens the total time required for heating when a relatively long time is required to heat the objects 1 and 2. Furthermore, because the microwave irradiation direction from the bottom magnetron 31A and the microwave irradiation direction from the rear magnetron 31B are different, uneven heating of the objects 1 and 2 can be suppressed.

[0064] 5 shows another example of control of the magnetrons 31A and 31B by the control unit 50 during microwave heating. In this example, the control unit 50 simultaneously operates both the bottom magnetron 31A and the rear magnetron 31B. In this control, due to the maximum power consumption, the two magnetrons 31A and 31B are each operated at a power (e.g., 350 W) that is less than half the maximum power (1000 W) that can be input when only one magnetron 31A or 31B is operated. However, the power input to one of the two magnetrons 31A and 31B may be different from the power input to the other.

[0065] 6 shows an example of control of the magnetrons 31A, 31B, and heater 38 by the control unit 50 during composite heating. In this example, the control unit 50 repeatedly performs the following steps for every set time t: a first step in which the bottom magnetron 31A is activated and the rear magnetron 31B and heater 38 are deactivated; a second step in which the rear magnetron 31B is activated and the bottom magnetron 31A and heater 38 are deactivated; and a third step in which the heater 38 is activated and the two magnetrons 31A, 31B are deactivated. In other words, the control unit 50 repeatedly performs control for every set time t, activating one of the heating units, including the two magnetrons 31A, 31B and heater 38, deactivating the other, and then activating the other and deactivating the other. However, the order in which the magnetrons 31A, 31B and heater 38 are activated can be changed as necessary. The set time t for switching the operation is the same as in the control shown in Fig. 4. In the composite heating process, the magnetrons 31A, 31B and the heater 38 may all be operated simultaneously, as in the control shown in Fig. 5.

[0066] In the control shown in Figures 4 and 6, one of the magnetrons 31A, 31B and the heater 38 can be operated at the maximum power that can be applied, so the heating efficiency of the object 1 can be improved and the total time required for heating can be shortened compared to the control shown in Figure 5. On the other hand, in the control shown in Figure 5, the power that can be applied to each of the magnetrons 31A, 31B is lower compared to the control shown in Figures 4 and 6, but the entire object 1 can be heated with so-called low heat, so uneven heating can be suppressed.

[0067] The microwave oven 10 configured as above has the following features.

[0068] Power supply units 33A and 33B that radiate microwaves are disposed below bottom wall 15 and behind rear wall 18, respectively. Because bottom wall 15 and rear wall 18 are close to object 1 to be heated, microwaves that diffuse with increasing distance from power supply units 33A and 33B can be concentrated on object 1 to be heated. This makes it possible to improve the heating efficiency of objects 1 and 2 with a simple configuration. Moreover, because the microwave irradiation direction from magnetron 31A and the microwave irradiation direction from magnetron 31B are different and the two magnetrons 31A and 31B can be individually controlled by control unit 50, uneven heating of objects 1 and 2 can be suppressed.

[0069] The tray placed between the bottom power feeding part 33A and the rear power feeding part 33B inside the heating chamber 14 includes a heat-generating tray 40 that can generate heat using microwaves radiated from the bottom power feeding part 33A. This allows the heat from the heat-generating tray 40 to heat the bottom surface of the object 1 to be heated, and the microwaves radiated from the rear power feeding part 33B to heat the object 1 from the inside. This not only improves the heating efficiency of the object 1 to be heated, but also prevents uneven heating of the object 1 to be heated.

[0070] The tray disposed between the bottom wall 15 and the rear power feeding unit 33B in the heating chamber 14 includes a transparent tray 41 that is permeable to microwaves. This allows the object 1 to be heated by the microwaves radiated from the bottom power feeding unit 33A and the microwaves radiated from the rear power feeding unit 33B. This not only improves the heating efficiency of the object 1, but also prevents uneven heating of the object 1.

[0071] The tray placed between bottom wall 15 and rear power feed unit 33B inside heating chamber 14 includes reflective tray 42 capable of reflecting microwaves. This allows object 2 placed on bottom wall 15 to be heated by microwaves radiated from bottom power feed unit 33A, and object 1 placed on reflective tray 42 to be heated by microwaves radiated from rear power feed unit 33B. Therefore, different objects 1 and 2 can be heated simultaneously and individually, which improves the heating efficiency of objects 1 and 2 and also improves user convenience.

[0072] At least a portion of rear power feeding portion 33B is located above the upper ends of trays 40 to 42. This reliably improves the heating efficiency of objects 1 placed on trays 40 to 42 and reliably prevents uneven heating of objects 1.

[0073] All rear power feeding parts 33B are located above the upper ends of trays 40 to 42. This reliably improves the heating efficiency of the objects 1 placed on trays 40 to 42. For example, when a reflective tray 42 is used and objects 1 and 2 are placed on the reflective tray 42 and on the bottom wall 15, respectively, the object 1 on the reflective tray 42 can be heated individually by the rear magnetron 31B, and the object 2 on the bottom wall 15 can be heated individually by the bottom magnetron 31A, thereby improving the heating efficiency of the objects 1 and 2.

[0074] The first projection area 34A of the bottom power feeding part 33A and the second projection area 34B of the rear power feeding part 33B overlap each other in an overlapping area 35. By placing the object 1 in the overlapping area 35, the heating efficiency of the object 1 can be effectively improved and uneven heating of the object 1 can be effectively suppressed.

[0075] The overlapping area 35 is located in the center between the pair of side walls 17 and in the center between the rear wall 18 and the door 25. Since users often place the object 1 to be heated in the center of the heating chamber 14, the heating efficiency of the object 1 to be heated can be reliably improved and uneven heating of the object 1 to be heated can be reliably suppressed.

[0076] Since rear power supply unit 33B is disposed on rear wall 18 instead of top wall 16, heater 38 can be disposed on top wall 16. This allows for composite heating treatment in which the center of object 1 to be heated is heated by microwaves from magnetrons 31A and 31B, and the outside of object 1 to be heated by radiant heat from heater 38. This improves user convenience.

[0077] The control unit 50 repeatedly controls one of the magnetrons 31A and 31B to operate and stop the other, then activate the other and stop the other, at predetermined intervals t. Alternatively, the control unit 50 repeatedly controls one of the heating units, including the magnetrons 31A and 31B and the heater 38, to operate and stop the other, then activate one of the units other than the one that was activated and stop the other, at predetermined intervals t. The magnetrons 31A and 31B have a limited operating time because they reach high temperatures when operated continuously. Therefore, for objects 1 and 2 that require a relatively long heating time, ensuring a rest period for the magnetrons 31A and 31B reduces heating efficiency. In contrast, in this embodiment, the multiple heating units, including the magnetrons 31A and 31B, are operated one at a time, so that when the magnetron 31A or 31B is operated at the maximum available power, the other magnetron 31A or 31B can be paused. Therefore, compared to when multiple heating units are operated simultaneously, the heating efficiency of the objects 1 and 2 can be improved and the total time required for heating can be shortened. Also, since the direction of microwave irradiation by magnetron 31A and the direction of microwave irradiation by magnetron 31B are different, uneven heating of the objects 1 and 2 can be suppressed.

[0078] Alternatively, the control unit 50 simultaneously operates the magnetrons 31A and 31B. This reduces the power that can be input to each of the magnetrons 31A and 31B compared to when the magnetrons 31A and 31B are operated alternately, but it allows the objects to be heated 1 and 2 to be heated entirely at a low heat, thereby preventing uneven heating.

[0079] Other embodiments and various modifications of the present invention will be described below, but in these descriptions, points that are not particularly mentioned are the same as those in the first embodiment. In the drawings referred to below, the same elements as those in the first embodiment are given the same reference numerals.

[0080] (Second embodiment) 7 to 9, microwave oven 10 of the second embodiment differs from microwave oven 10 of the first embodiment in that it has an intermediate guide rail 24 in addition to upper and lower guide rails 22, 23, that it has a different arrangement of microwave emission section 21 radiated by rear magnetron 31B, and that it is equipped with infrared sensors 44A, 44B that individually detect the temperatures of objects 2, 1 to be heated.

[0081] The intermediate guide rails 24, like the lower guide rails 22 and the upper guide rails 23, are configured to place trays 40 to 42 on which the objects to be heated 1 are placed. The intermediate guide rails 24 are provided on the pair of side walls 17 at the same height position between the lower guide rail 22 and the upper guide rail 23.

[0082] The pair of intermediate guide rails 24 are provided so that the bottom surfaces of the trays 40-42 are positioned approximately in the center of the overall height of the heating chamber 14. The pair of lower guide rails 22 are provided between the intermediate guide rails 24 and the bottom wall 15. The pair of upper guide rails 23 are provided between the intermediate guide rails 24 and the top wall 16. The guide rails 22-24 are all formed in the shape of a right triangle with their upper ends extending along the XY plane. In the second embodiment, of the three types of guide rails 22-23, the pair of intermediate guide rails 24 constitute the tray holding means of the present invention that positions the trays 40-42 in the heating chamber 14 along the bottom wall 15.

[0083] By arranging the trays 40-42 on the intermediate guide rail 24, the heating chamber 14 is divided into a lower heating chamber section 14A below the trays 40-42 and an upper heating chamber section 14B above the trays 40-42. By arranging the heat-generating tray 40 or the reflective tray 42 on the intermediate guide rail 24, it is possible to suppress the transmission of microwaves between the lower heating chamber section 14A and the upper heating chamber section 14B. By arranging the transparent tray 41 on the intermediate guide rail 24, it is possible to allow the transmission of microwaves between the lower heating chamber section 14A and the upper heating chamber section 14B.

[0084] As in the first embodiment, the bottom wall 15 and the rear wall 18 are each composed of a wall main body portion 20 and a discharge portion 21. Of these, the wall main body portion 20 of the bottom wall 15 has a recess 20a formed so that the discharge portion 21 accounts for half or more (e.g., 80%) of the total area, as in the first embodiment. On the other hand, in the wall main body portion 20 of the rear wall 18 of the second embodiment, the recess 20a is formed so that the lower end 21a of the discharge portion 21 is positioned at the same height as the upper ends of the trays 40 to 42 placed on the intermediate guide rail 24. However, the lower end 21a of the discharge portion 21 may be positioned higher than the upper ends of the trays 40 to 42 placed on the intermediate guide rail 24.

[0085] As in the first embodiment, the magnetrons 31A and 31B radiate microwaves into the heating chamber 14 via waveguides 32A and 32B, power feeders 33A and 33B, and antennas 36A and 36B, respectively. Among them, the rear waveguide 32B of the rear magnetron 31B differs from the rear waveguide 32B of the first embodiment only in that it extends upward so as to be positioned at the center of the recess 20a of the rear wall 18.

[0086] The heater 38 of the second embodiment is made of a sheet-like mica heater and is installed on the upper side (outside the heating chamber 14) of the flat top wall 16 without providing a recess 16a in the top wall 16. However, the upper heater 38 arranged on the upper side of the top wall 16 may be a pipe heater similar to that of the first embodiment, or may be an incoloy heater.

[0087] In the second embodiment, a heater 39 is also attached inside the recess 20a of the bottom wall 15. The lower heater 39 is configured as a pipe heater piped inside the recess 20a so as to surround the bottom antenna 36A, and is connected to the control unit 50 (see FIG. 9). However, the lower heater 39 may also be configured as an incoloy heater or a mica heater.

[0088] The infrared sensors 44A and 44B are attached to the outside of one of the pair of side walls 17 (the right side in FIG. 8 ) at a vertical interval and are each connected to the control unit 50 (see FIG. 9 ). More specifically, the lower infrared sensor 44A is a lower temperature detection unit for detecting the temperature of the object 2 placed on the bottom wall 15 in the lower heating chamber section 14A. The lower infrared sensor 44A is disposed in a recess in one of the pair of intermediate guide rails 24 so as to be able to detect the object 2 placed in the center of the bottom wall 15, and faces the interior of the heating chamber 14 through a through-hole (not shown). The upper infrared sensor 44B is an upper temperature detection unit for detecting the temperature of the object 1 placed on the trays 40-42 in the upper heating chamber section 14B. The upper infrared sensor 44B is disposed on the outside of the side wall 17 between the upper guide rail 23 and the top wall 16 so as to be able to detect the object 1 placed in the center of the trays 40-42, and faces the interior of the heating chamber 14 through a through-hole (not shown).

[0089] As in the first embodiment, the control unit 50 individually controls the magnetrons 31A, 31B and the heaters 38, 39 in accordance with a program determined according to the selected heating process, and performs microwave heating, hybrid heating, and heater heating. Moreover, in the second embodiment, the infrared sensors 44A, 44B can detect the temperatures of the objects 2, 1, respectively, so that the control unit 50 can perform precise control when simultaneously and individually heating the objects 2, 1 in the lower heating chamber 14A and the upper heating chamber 14B by microwave heating, as will be described in detail below as an example.

[0090] When a reflective tray 42 is placed on the intermediate guide rail 24 and the objects to be heated 2, 1 are simultaneously heated to a target temperature T1 (e.g., 70°C) in the lower heating chamber 14A and the upper heating chamber 14B, the control unit 50 sets a confirmation temperature T2 (e.g., 60°C) according to the target temperature T1. The control unit 50 then first controls the bottom magnetron 31A based on the detection result of the lower infrared sensor 44A, and controls the rear magnetron 31B based on the detection result of the upper infrared sensor 44B. Next, if the object to be heated 2 in the lower heating chamber 14A has risen to the confirmation temperature T2 but the object to be heated 1 in the upper heating chamber 14B has not yet risen to the confirmation temperature T2, the control unit 50 controls the input power of the bottom magnetron 31A to be lower (weaker heating power) and controls the input power of the rear magnetron 31B to be higher (stronger heating power). In other words, when the control unit 50 determines based on the detection results of the infrared sensors 44A, 44B that one of the upper and lower heated objects 2, 1 has risen in temperature to the confirmation temperature T2 but the other has not, it reduces the input power of the magnetron 31A or 31B that has risen in temperature and increases the input power of the other magnetron 31A or 31B that has not risen in temperature.

[0091] The control unit 50 may also perform control as follows: When there is a possibility that microwaves from the rear magnetron 31B are affecting the object to be heated 2 in the lower heating chamber section 14A, the control unit 50 controls the rear magnetron 31B based on the detection result of the lower infrared sensor 44A. On the other hand, when there is a possibility that microwaves from the bottom magnetron 31A are affecting the object to be heated 1 in the upper heating chamber section 14B, the control unit 50 controls the bottom magnetron 31A based on the detection result of the upper infrared sensor 44B.

[0092] That is, the control unit 50 controls the bottom magnetron 31A and the rear magnetron 31B individually based on the detection results of the lower infrared sensor 44A and the upper infrared sensor 44B, respectively. This allows the heating states of the object 2 to be heated in the lower heating chamber 14A and the object 1 to be heated in the upper heating chamber 14B to be aligned and simultaneously heated to the target temperature T1.

[0093] Furthermore, microwave oven 10 of the second embodiment also includes heater 39 below bottom wall 15. Therefore, in the composite heating process or heater heating process, object 1 to be heated on trays 40 to 42 can be heated by radiant heat from lower heater 39.

[0094] The microwave oven 10 of the second embodiment configured as above has the following features.

[0095] The heating chamber is provided with a lower infrared sensor 44A that detects the temperature of the object 2 to be heated in the lower heating chamber 14A, and an upper infrared sensor 44B that detects the temperature of the object 1 to be heated in the upper heating chamber 14B. This allows the bottom magnetron 31A and the rear magnetron 31B to be controlled according to the heating status of each of the objects 2 and 1 to be heated placed in the lower heating chamber 14A and the upper heating chamber 14B. This improves the heating efficiency of each of the objects 2 and 1 to be heated.

[0096] The control unit 50 individually controls the bottom magnetron 31A and the rear magnetron 31B based on the detection results of the lower infrared sensor 44A and the upper infrared sensor 44B. For example, the control unit 50 controls the bottom magnetron 31A based on the detection result of the lower infrared sensor 44A, and controls the rear magnetron 31B based on the detection result of the upper infrared sensor 44B. In this way, the bottom magnetron 31A and the rear magnetron 31B are individually controlled according to the heating conditions of the individual objects to be heated placed in the lower heating chamber 14A and the upper heating chamber 14B, so that the individual objects to be heated can be reliably heated to the desired state without uneven heating.

[0097] The lower end 21a of the emission portion 21 of the rear magnetron 31B is positioned at a height equal to or higher than the upper end of the reflective tray 42. As a result, the positioning of the reflective tray 42 can suppress the transmission of microwaves between the lower heating chamber section 14A and the upper heating chamber section 14B. In other words, the reflective tray 42 can essentially divide the interior of the heating chamber 14 into the lower heating chamber section 14A and the upper heating chamber section 14B. Therefore, the bottom magnetron 31A can reliably heat the object 2 to be heated in the lower heating chamber section 14A, and the rear magnetron 31B can reliably heat the object 1 to be heated in the upper heating chamber section 14B. As a result, it is easy to create a control program for simultaneously and individually heating different objects 2, 1 to be heated placed in the lower heating chamber section 14A and the upper heating chamber section 14B.

[0098] A heater 39 is disposed below the bottom wall 15 of the heating chamber 14. This allows the objects 1 to be heated placed on trays 40 to 42 placed in the heating chamber 14 to be heated by radiant heat from the heater 39. This not only improves the heating efficiency of the objects 1 to be heated, but also improves user convenience.

[0099] The present invention is not limited to the configuration of the above embodiment, and various modifications are possible.

[0100] For example, three or more magnetrons may be used as the heating section, or a configuration may be adopted in which heaters 38, 39 are not used. Furthermore, microwave oven 10 of the second embodiment may be equipped with only lower heater 39 without upper heater 38. When heater 38 is not used, a magnetron power feed section may be disposed on top wall 16 separately from bottom power feed section 33A and rear power feed section 33B. Furthermore, a power feed section may be disposed on side wall 17 separately from bottom power feed section 33A and rear power feed section 33B. When power feed sections are provided in places other than bottom wall 15 and rear wall 18, waveguides 32A, 32B may be branched and magnetrons 31A, 31B may be shared, or dedicated waveguides and magnetrons may be used.

[0101] The bottom wall 15 and the rear wall 18 may each be provided with a plurality of emitting portions 21 that radiate microwaves into the heating chamber 14 .

[0102] When a tray is used to place the object to be heated 1, the tray may be one or two of the heat-generating tray 40, the translucent tray 41, and the reflective tray 42. In other words, it is sufficient that the configuration includes at least one of the heat-generating tray 40, the translucent tray 41, and the reflective tray 42.

[0103] First projection area 34A of bottom power feeding part 33A and second projection area 34B of rear power feeding part 33B may be arranged so that there is no overlapping area 35. Of course, bottom power feeding part 33A and rear power feeding part 33B may be arranged in a location other than the center between pair of side walls 17 and the center between rear wall 18 and door 25.

[0104] The control of the magnetrons 31A, 31B and the heater 38 by the control unit 50 can be changed as needed as long as the configuration allows the object to be heated 1 or 2 to be heated evenly and efficiently. [Explanation of symbols]

[0105] 1,2 Heated object 10. Microwave 12 Microwave oven body 13. Cabinet 14 Heating cabinet 14A Lower heating chamber 14B Upper heating chamber 15 Bottom Wall 16 Ceiling wall 16a Recess 17 Side wall 18 Back wall 20 Wall body 20a Recess 21 Emission part 21a Bottom end 22 Lower guide rail (tray holding means in the first embodiment) 23 Upper guide rail 24 Intermediate guide rail (tray holding means of the second embodiment) 25 Doors 26 Door body 27 Window 28 Reflective layer 31A Bottom Magnetron (heating unit, bottom microwave source) 31B Rear magnetron (heating unit, rear microwave source) 32A bottom waveguide 32B rear waveguide 33A bottom power supply 33B Rear power supply section 34A 1st projection area 34B 2nd projection area 35 Overlapping area 36A bottom antenna 36B rear antenna 37A bottom motor 37B Rear motor 38 Heater (heating part) 39 Lower heater 40 Heating Tray 41 Transparent tray 42 Reflective Tray 44 Infrared sensor 44A Lower infrared sensor (lower temperature detection part) 44B Upper infrared sensor (upper temperature detection part) 45 Thermistor 47 Operation Panel 48 LCD panel 49 Switch 50 control section 51 memory 52 Timer

Claims

1. a heating chamber defined by a bottom wall, a top wall, a pair of side walls, a rear wall, and a door; A bottom microwave source and a rear microwave source are respectively arranged outside the heating chamber; A bottom power supply unit is arranged below the bottom wall and radiates microwaves emitted by the bottom microwave source into the heating chamber through the bottom wall; a rear power supply unit disposed behind the rear wall and configured to radiate microwaves emitted by the rear microwave source into the heating chamber through the rear wall; a control unit that individually controls the bottom microwave source and the rear microwave source; Equipped with a microwave oven.

2. A tray holding means for placing a tray on which an object to be heated is placed along the bottom wall is provided between the bottom power supply unit and the rear power supply unit in the heating chamber, 2. The microwave oven of claim 1, wherein the tray comprises at least one of a heat-generating tray capable of generating heat by microwaves, a transparent tray capable of transmitting microwaves, and a reflective tray capable of reflecting microwaves.

3. 3. The microwave oven according to claim 2, wherein at least a portion of the rear power supply unit is located above an upper end of the tray when the heating chamber is viewed from the door side.

4. 4. The microwave oven according to claim 3, wherein all of the rear power supply units are located above an upper end of the tray when the heating chamber is viewed from the door side.

5. 5. The microwave oven according to claim 1, wherein a first projection area of ​​the bottom power supply unit extending from the bottom wall toward the top wall and a second projection area of ​​the rear power supply unit extending from the rear wall toward the door have an overlapping area.

6. 6. The microwave oven of claim 5, wherein the overlapping area is located centrally between the pair of side walls and centrally between the rear wall and the door.

7. The microwave oven according to claim 1 , wherein a heater is disposed on the top wall.

8. 5. The microwave oven according to claim 1, wherein the control unit repeatedly performs control at predetermined time intervals to operate one of the bottom microwave source and the rear microwave source and stop the operation of the other, and then operate the other and stop the operation of the one.

9. 8. The microwave oven according to claim 7, wherein the control unit repeatedly performs control at predetermined time intervals to operate one of a plurality of heating units including the bottom microwave source, the rear microwave source, and the heater, stop the operation of the remaining units, and then operate one other than the one that was operated, and stop the operation of the remaining units.

10. The microwave oven according to claim 1 , wherein the control unit simultaneously operates the bottom microwave source and the rear microwave source.

11. The tray can divide the heating chamber into a lower heating chamber section below the tray and an upper heating chamber section above the tray, A lower temperature detection unit that detects the temperature of the object to be heated in the lower part of the heating chamber; an upper temperature detection unit that detects the temperature of the object to be heated in the upper part of the heating chamber; The microwave oven according to any one of claims 2 to 4, further comprising:

12. The microwave oven according to claim 11, wherein the control unit controls the bottom microwave source and the rear microwave source individually based on the detection results of the lower temperature detection unit and the upper temperature detection unit, respectively.

13. 13. The microwave oven of claim 12, wherein the control unit controls the bottom microwave source based on the detection result of the lower temperature detection unit, and controls the rear microwave source based on the detection result of the upper temperature detection unit.

14. The tray is made of the reflective material, 12. The microwave oven of claim 11, wherein a lower end of the emission portion of the rear microwave source is disposed at a height equal to or higher than a height of an upper end of the reflective tray.

15. The microwave oven according to claim 1 , wherein a heater is disposed below the bottom wall of the heating chamber.

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