JP2008258006A - Microwave heating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microwave heating apparatus which can safely achieve an entire and uniform heating with a high precision. <P>SOLUTION: The microwave heating apparatus is provided with rotatable antennas 38, 39 which discharge microwave from a microwave generating means 32 to a heating chamber and a controlling means 60 to drive and rotate the rotatable antennas and control directions of the rotatable antennas. The rotatable antennas have a portion of strong discharging directionality and the controlling means makes the portion of strong discharging directionality of the rotatable antennas to face to a predetermined point and a local and intensive heating is conducted, and while the partial and intensive heating is conducted, the portion of strong discharging directionality is rocked several times, and as a result, a low temperature portion in the heating chamber can be targeted and heated and an entire and uniformed heating can be achieved with a high precision. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a microwave heating apparatus that dielectrically heats an object to be heated.

  A microwave oven, which is a typical microwave heating device, can directly heat food, which is a typical object to be heated, so it becomes an essential device in daily life with the simplicity that does not require the preparation of a pan or pot. ing. In the microwave oven, the size of the space for storing food in the heating chamber through which microwaves propagate is approximately 300 to 400 mm in the width direction and the depth direction, and approximately 200 mm in the height direction. And this kind of microwave heating apparatus was conventionally provided with one radiation antenna, and it was the composition which rotationally drives the antenna (for example, refer to patent documents 1).

  On the other hand, in recent years, the shape of the horizontally long heating chamber has been improved by making the bottom surface of the space for storing food flat, further increasing the width dimension to 400 mm or more and making it relatively larger than the depth dimension, so that a plurality of dishes can be arranged and heated. However, in such a heating chamber with a large size in the width direction, it is necessary to increase the uniformity of heating in order to heat food placed on multiple dishes at the same time. was there.

  Therefore, as a measure for improving the uniformity of heating in such a heating chamber, one provided with a plurality of radiation antennas or one provided with a plurality of high-frequency stirring units has been proposed (for example, see Patent Document 2).

However, even if the interior is large, it does not always heat a large amount of food. For example, when heating a full mug of milk, it is considered more efficient to concentrate only on milk without heating the entire interior uniformly. . Also, even when heating multiple foods at the same time, if there is a difference in the temperature of the food, for example, when heating frozen food and food at room temperature at the same time, you may want to heat only the low-temperature food intensively. is there. In addition, if it is like a bento box lunch, one container contains foods (pickles, salads, desserts, etc.) that you do not want to heat, and only the foods to be heated (rice, side dishes, etc.) are heated intensively. Sometimes you want to. In such a case, the function which can carry out local concentration heating instead of the whole uniform heating is needed. For this purpose, Patent Document 2 describes that concentrated heating is performed by switching a plurality of radiation antennas and controlling a stop position.
JP-A-9-27389 JP 2006-286443 A

  However, in the microwave heating apparatus disclosed in Patent Document 2, local concentrated heating is possible depending on the purpose, and uniform heating is also actual, but the rotating antenna is stopped to perform local concentrated heating. Due to the lengthened state, there is a risk of occurrence of a red spot (spot melting in the chamber) due to the microwaves concentrating on one point other than the object to be heated.

  This invention is made | formed in view of the situation which concerns, and it aims at providing the microwave heating apparatus which can implement | achieve highly accurate whole uniform heating, without generating a red spot.

  The microwave heating apparatus of the present invention controls a microwave generating means, a rotating antenna that radiates microwaves from the microwave generating means to a heating chamber, a driving means that rotationally drives the rotating antenna, and the driving means. Control means for controlling the direction of the rotating antenna, the rotating antenna having a portion having a strong radiation directivity, and the control means directing the portion having a strong radiation directivity of the rotating antenna to a predetermined location. In addition, local concentrated heating is performed, and a portion having a strong radiation directivity of the rotating antenna is swung several times during the local concentrated heating.

  According to the above configuration, it becomes possible to heat the portion where the low-temperature object to be heated is placed in the heating chamber, to achieve high-accuracy overall uniform heating, and when the rotating antenna stops, It is possible to prevent the occurrence of a red spot (spot-like melting in the cabinet) due to the microwaves concentrating on one point other than the object to be heated.

  According to the microwave heating apparatus of the present invention, it is possible to achieve high-precision overall uniform heating and to prevent the occurrence of a red spot (spot melting in the chamber) when the rotating antenna stops, A microwave heating apparatus capable of safe and good heating can be provided.

  The first invention includes a microwave generating means, a rotating antenna that radiates microwaves from the microwave generating means to a heating chamber, a driving means that rotationally drives the rotating antenna, and the driving means that controls the driving Control means for controlling the orientation of the rotating antenna, the rotating antenna has a portion having a strong radiation directivity, and the control means is configured to locally concentrate the portion having the strong radiation directivity of the rotating antenna toward a predetermined location. In addition to causing heating, the portion having a strong radiation directivity of the rotating antenna is swung several times during the local concentrated heating, and heating is aimed at the portion where the object to be heated in the heating chamber is placed. It is possible to achieve uniform heating with high accuracy, and when the rotating antenna stops, the microwave concentrates on one point other than the object to be heated. It is possible to prevent the occurrence of a red spot (spot that melts in the refrigerator) by.

  According to a second aspect of the invention, there is provided a microwave generating means, a waveguide for transmitting microwaves from the microwave generating means, a heating chamber connected to the waveguide, and the heating for placing an object to be heated. A mounting table disposed in the room; a heated object storage space formed above the mounting table in the heating chamber; an antenna space formed below the mounting table in the heating chamber; and the waveguide A rotating antenna having a radiation directivity disposed in the antenna space from the waveguide, a driving means for rotationally driving the rotating antenna, and controlling the driving means. Control means for controlling the direction of the rotating antenna, and the control means causes the localized concentrated heating of the rotating antenna having a strong radiation directivity toward a predetermined position and the localized concentrated heating. The rotary antenna has a structure in which a portion having a strong radiation directivity is swung several times, and the same effect as the first invention can be obtained, and the accuracy of uniform heating can be improved by using a plurality of rotary antennas. Can do.

  According to a third invention, in the first and second inventions, the heating chamber is formed in a horizontally long shape whose width direction is long with respect to the depth, and a plurality of rotating antennas are provided along the width direction of the heating chamber, and The control means rotates the plurality of rotating antennas to uniformly heat the object to be heated in the heating chamber and / or directs at least one of the plurality of rotating antennas with a strong radiation directivity toward a predetermined position. Even if it is a structure provided with a horizontally long heating chamber, uniform heating and local concentrated heating can be achieved with high accuracy.

  According to a fourth invention, in the first to third inventions, the control means swings the rotating antenna to be swung within a range of 10 degrees or less, and the angle for swinging the rotating antenna is 10 degrees. By making it within the range, it is possible to prevent the occurrence of a red spot, and it is possible to maximize the accuracy of the concentrated heating due to the swing of the rotating antenna.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described in detail with reference to the drawings.

  1 to 4 are configuration diagrams of a microwave heating apparatus according to an embodiment of the present invention. FIG. 1 is a cross-sectional view seen from the front, FIG. 2 is a cross-sectional view taken along line AA ′ of FIG. Is a sectional view taken along the line BB 'in FIG. 1, FIG. 4 is a data processing diagram of the infrared sensor, and FIG. 5 is a block division example of the sectional view taken along the line CC' in FIG. Note that the microwave heating apparatus of the present embodiment is the one in which the present invention is applied for cooking for heating and thawing food, but for cooking, heating, drying, sintering, Of course, the present invention can also be applied to uses such as biochemical reactions.

  The microwave heating device 31 has a waveguide 33 that transmits a microwave radiated from a magnetron 32, which is a typical microwave generation means, and a width dimension (about 410 mm) connected to the upper portion of the waveguide 33. A heating chamber 34 having a shape larger than the dimension in the depth direction (about 315 mm) and a typical food to be heated (not shown) are placed in the heating chamber 34 to place low loss such as ceramic and glass. A mounting table 35 having a property that microwaves can be easily transmitted because it is made of a dielectric material, and a heated object storage space 36 that is formed above the mounting table 35 in the heating chamber 34 and can substantially store food. And the antenna space 37 formed below the mounting table 35 in the heating chamber 34 and the microwave in the waveguide 33 are radiated into the heating chamber 34. The two rotating antennas 38 and 39 attached at symmetrical positions with respect to the width direction of the heating chamber 34, motors 40 and 41 as representative driving means capable of rotationally driving the rotating antennas 38 and 39, and the motor 40 , 41 to control the orientation of the rotating antennas 38, 39, and a memory 61 for storing the stopping positions of the rotating antennas 38, 39, etc. A specific food is concentratedly heated by controlling a portion having a strong radiation directivity in a predetermined direction. The specific control method will be described later.

  The rotary antennas 38 and 39 are conductive materials having a diameter of about 18 mm and a substantially cylindrical shape that pass through the coupling holes 43 and 44 having a diameter of about 30 mm provided on the boundary surface between the waveguide 33 and the bottom surface 42 of the heating chamber. The coupling portions 45 and 46, and the coupling portions 45 and 46 are electrically connected to and integrated with the upper ends of the coupling portions 45 and 46 by caulking or welding, and are made of a conductive material having a larger area in the horizontal direction than in the vertical direction. Parts 47 and 48, and the coupling holes 43 and 44 are fitted to the shafts 49 and 50 of the motors 40 and 41 so that the centers of the coupling holes 43 and 44 are rotationally driven. On the other hand, since the shape is not constant, the radiation directivity is adopted.

Since the waveguide 33 has a T-shape when viewed from above as shown in FIG. 3 and has a bilaterally symmetric shape, the distance from the magnetron 32 to the coupling portions 45 and 46 is equal, and the coupling portions 45 and 46 are the same. Are attached at symmetrical positions also in the width direction of the heating chamber 34, so that the microwaves radiated from the magnetron 32 are substantially evenly distributed in the heating chamber 34 via the waveguide 33 and the rotating antennas 38 and 39. Distributed. The waveguide may be straight and may have an I shape in which a magnetron is disposed at one end and a coupling portion is provided between the waveguide and the other end. The microwaves can be distributed substantially evenly.

The radiating portions 47 and 48 have the same shape, and the radiating portion upper surfaces 51 and 52 have a substantially quadrilateral R shape, and the radiating portion bending portion 53 bent to the heating chamber bottom surface 42 side on the opposite two sides, 54, and is configured to limit the emission of microwaves to the outside of the two sides. The distance between the heating chamber bottom surface 42 and the radiating portion upper surfaces 51 and 52 is about 10 mm, and the radiating portion bending portions 53 and 54 are pulled down to a position lower by about 5 mm. The remaining two sides have different horizontal lengths from the coupling portions 45 and 46 to the end portions, and the end portions 55 and 56 and the coupling portions 45 and 46 whose length from the center of the coupling portions 45 and 46 is about 75 mm. The end portions 57 and 58 having a length from the center of about 55 mm are formed. Moreover, the dimension of the width direction of the edge parts 45 and 46 is 80 mm or more. In this configuration, the rotating antennas 38 and 39 can increase the radiation directivity in the direction from the coupling portions 45 and 46 to the end portions 57 and 58.

The control unit 60 drives a CPU (Central Processing Unit), a nonvolatile memory such as a ROM storing a program for controlling the CPU, a volatile memory such as a RAM used for the operation of the CPU, and the motors 40 and 41. A driver and a drive circuit for driving the magnetron 32 (both not shown) are provided. The memory 61 is a non-volatile memory such as a flash memory that can be rewritten and does not lose data even when the power is turned off.

  In this configuration, when heating general foods uniformly, it is not necessary to be particular about the place of placement as in the conventional microwave heating device, and the rotating antennas 38 and 39 are also rotated at a constant speed as in the prior art. Alternatively, if there is a pattern for heating uniformly with a constant rotation / stop pattern, that may be used. On the other hand, in the case of central heating, control is performed using temperature data (temperature detection information) input by an infrared sensor (temperature detection means) 59, but a plurality of blocks are used in the interior to determine the location for central heating. The control unit 60 determines which block is targeted and performs concentrated heating. However, since the temperature data varies depending on the attachment position of the infrared sensor 59, the block division method when attached to the right side surface will be described with reference to FIGS.

  FIG. 4A is a data processing diagram of the infrared sensor 59 when the eight-element type infrared sensor 59 attached to the right side surface is scanned from the back to acquire data at address 19. In this case, as shown in FIG. 4 (b), in the case of 8 elements and 1 element, the visible range is the same as that of the infrared sensor 59 as long as it is a vertical plane. Since the visible range from the infrared sensor 59 differs depending on the position of the food on the right side, it is necessary to consider when dividing the block. FIG. 5 shows an example of block division when attached to the right side surface. The areas shown by the oblique lines [1] and [14] are not processed when viewed from the infrared sensor 59 because they see a place where food in the warehouse is not placed. Similarly, since the visible width of the infrared sensor 59 is different between the front and back, the central area is finely divided, but the front and back are slightly wider. Incidentally, the area indicated by the diagonal line [1] is an area where steam is generated, and the area indicated by the diagonal line [14] is an area near the door. Do not place food in these areas.

  The control unit 60 obtains the average temperature of the portion where it is determined that food is placed for each of the divided blocks as shown in FIG. 5, and if there is a block having a low temperature, the rotating antenna is used to centrally heat the food. The food can be heated intensively by controlling the end portions 57 and 58 of the 38 and 39 with a rotation / stop pattern capable of centrally heating the low temperature block.

  In addition, as a method of determining the point of the portion where the food is placed, there is a method of determining whether the food is based on the difference between the initial temperature and the temperature after a certain period of time, but the width of each point visible from the infrared sensor 59 Are different on the left, right, near side, and back, so that the blocks to be heated centrally are weighted so as not to be erroneously determined. As a method for this, the number of points where food is placed in each block is multiplied by a predetermined value determined in advance for each block to reduce variation.

In order to turn the rotating antennas 38 and 39 in a predetermined direction, a stepping motor is used as the motors 40 and 41, or even if the motor rotates at a constant speed, the reference position is detected and stopped by the energization time from the reference position. Various methods such as controlling the position can be considered.

  Next, specific control will be described. In FIG. 2, the setting part 62 is arrange | positioned at the lower part of the door 63, and it is determined whether the control part 60 performs concentrated heating based on the content which the user set using the setting part 62. In FIG. Based on the determination result, the control unit 60 controls the magnetron 32 and the motors 40 and 41. For example, when the user sets “rice warming” by the setting unit 62, the control unit 60 rotates the rotating antennas 38 and 39 by the motors 40 and 41 so that the whole is uniform for a certain period of time. To control. And after a certain period of time, compare the average temperature difference at the point where it is determined that there is food for each block, and if the temperature difference is more than a certain temperature, concentrate and heat the low temperature block, When the temperature difference disappears, control is performed so as to return to the uniform heating pattern.

  On the other hand, when the user sets “milk warming” by the setting unit 62, the control unit 60 determines that central heating is necessary, drives the motors 40 and 41 to rotate the rotating antennas 38 and 39, and the radiation unit. Control is performed so that the end portions 57 and 58 of the 47 and 48 are stopped when they are respectively directed toward the center. This can intensively heat the bottom of the milk. At this time, the stop positions of the rotating antennas 38 and 39 are stored in the memory 61 by the control unit 60.

  As described above, according to the present embodiment, the two rotating antennas 38 and 39 coupled to the common waveguide 33 arranged on the lower side of the heating chamber 34 are positioned symmetrically with respect to the width direction of the heating chamber 34 having a wide width. Since they are arranged, at least a symmetrical heating distribution can be obtained, and the microwave radiation pattern can be varied as compared with the case of one rotating antenna. Thereby, the heating distribution of the whole inside of a store | warehouse | chamber can be equalized easily.

  In addition, by controlling the direction of the end portions 57 and 58, which are strong radiation directivities of both rotary antennas 38 and 39, microwaves can be radiated strongly in a predetermined direction, so the interior is divided. Centralized heating can be performed for each block. That is, the temperature detection information from the infrared sensor 59 can be intensively heated at the low temperature portion. Thereby, “frozen food” and “normal temperature rice” having different starting temperatures can be heated at the same time.

  In addition, there are infinite combinations for stopping / rotating control of the rotating antennas 38 and 39, so that the combination that achieves uniform heating, the control method can be changed for each block, and the combination can be changed for each menu. It is. Furthermore, for example, one side is stopped and the other is rotated, or one is stopped halfway and the other is rotated, and the one that has been stopped from the middle is rotated and the one that has been rotated is stopped. Various control methods are possible. Such a control method is effective in the case where it is desirable that the time between concentrated heating and uniform heating is desirable because concentrated heating is too concentrated. At this time, the ratio between rotation and stop may be optimized as appropriate.

Well, when performing local concentrated heating in this way, if the stop time of the rotating antenna is taken too long, a red spot (spot-like melting in the cabinet) due to the microwaves concentrating on one point other than food The occurrence of Therefore, in this embodiment, first, the rotating antennas 38 and 39 are swung about 10 degrees with a portion having a strong radiation directivity directed to a portion to be locally heated. This rocking may be performed continuously or by the method described below. That is, it is an oscillation that repeats stopping at an optimum stop position and about 5 degrees before and after the local concentrated heating. In this case, the total stop time of the rotating antennas 38 and 39 can be divided into three, and even if the local concentrated heating time is long, the individual stop time can be shortened, and red spots can be prevented more reliably. become. In this case, the angle may be any number of times, but is preferably 10 degrees or less in consideration of variations in the stop positions of the rotating antennas 38 and 39. If the angle is changed further, localized concentrated heating seems to be substantially difficult. If there is no pattern in which the two rotating antennas 38 and 39 stop simultaneously, or if the stop time is short, it may be unnecessary.

  Furthermore, the microwave heating device 31 of the present embodiment has a very simple configuration in which the directions of the two rotating antennas 38 and 39 coupled to one waveguide 33 are controlled, and the entire interior is uniformly heated. Even when switching between local and centralized heating, there is no risk of changing the coupling state of microwaves, and it is safe and there is no need for severe dimensional management such as gap management, so it is realized with a very realistic configuration it can.

  In addition, the microwave in the waveguide 33 is drawn out to the heating chamber 34 side from the gap between the coupling holes 43 and 44 and the coupling portions 45 and 46, but the radiation portion 47 integrated with the coupling portions 45 and 46, Since the shape of 48 is not a fixed shape (for example, a circle, a cylinder, a cone, a sphere, etc.) with respect to the direction of rotation, the ease of propagation of microwaves differs depending on the direction. In a direction where the radiation directivity is strong and difficult to propagate, the radiation directivity is such that the radiation directivity is weak. When the rotating antennas 38 and 39 are rotating at a constant speed, if a microwave with a constant output is radiated for a time sufficiently longer than the rotation period, the microwaves are averaged in the direction of rotation. Are heated at the same level and have a concentric heating distribution (for example, strong heating in a circular shape or strong heating in a donut shape).

  On the other hand, when the rotation antennas 38 and 39 are stopped or the rotation speed and the output of the microwave are changed to limit the heating mainly in a predetermined direction, the heating distribution is not concentric but is determined by the radiation directivity. An object to be heated (or a part of the object to be heated) in the vicinity of the portion having a strong radiation directivity of the rotating antennas 38 and 39 is easily heated strongly and can be heated intensively.

  Further, in this embodiment, the rotating antennas 38 and 39 are stopped and the microwave is continuously propagated in a state having a strong radiation directivity in a predetermined direction, so that a specific heated object is easily concentratedly heated. be able to.

  Further, in the present embodiment, since the central heating is performed by controlling the rotating antennas 38 and 39 based on the setting contents, the central heating is usually performed at a constant rotation, and the central heating is easily performed. And can be switched. From the user's point of view, the microwave heating device automatically switches between uniform heating and concentrated heating as long as the setting is made, so that the risk of mistakes can be reduced.

  As described above, according to the microwave heating apparatus 31 of the present embodiment, the control unit 60 divides the inside of the heating chamber 34 into a plurality of blocks, and blocks blocks whose temperature is low based on the temperature detection information from the infrared sensor 59. The motors 40 and 41 are controlled in order to perform the determination and concentrated heating aiming at the determined block, and a portion having a strong radiation directivity in at least one of the two rotating antennas 38 and 39 is set in a predetermined direction. Therefore, it becomes possible to strongly radiate the microwave toward the block having a low temperature, and it is possible to easily and intensively heat the portion of the object to be heated having a low temperature. Thereby, highly accurate whole uniform heating is realizable.

  Moreover, since the control part 60 determines the block with low temperature by comparing the average temperature difference of several points with low temperature regularly, even if the part in which food is not put in the block is included, Since only a certain portion of the food is judged and compared at the average temperature, the portion where the object to be heated is low can be intensively heated more reliably.

  In addition, the control unit 60 determines the total number of points of each block by multiplying the total number of points of each block by a predetermined value determined for each block for all the blocks in which low temperature points exist. When the temperature detection information varies depending on the attachment position of the sensor 59, it is possible to optimize the temperature detection information by weighting, and the portion where the temperature of the food is low can be heated more reliably.

  In addition, since the control unit 60 swings at least one rotating antenna several degrees with respect to the rotation direction when the two rotating antennas 38 and 39 are stopped, the microwaves other than the object to be heated are stopped when the rotating antenna is stopped. It becomes possible to prevent the portion from being heated, and to improve the accuracy of the concentrated heating by the swinging of the rotating antennas 38 and 39.

  In addition, the control unit 60 heats the whole uniformly at the beginning of heating, and concentrates the low temperature portion after a certain period of time, so that only the low temperature portion is centrally heated after the uniform heating as a whole. Can do.

  Further, the controller 60 uniformly heats the whole at the beginning of heating, and when there is a temperature difference after a certain period of time, the low temperature part is concentratedly heated. Can be heated uniformly.

  The present invention can achieve high-accuracy uniform heating throughout, and can prevent the occurrence of red spots (spot-like melting in the cabinet) when the rotating antenna stops, enabling safe and good heating. And can be applied to uses such as heating, thawing, ceramics heating, drying, sintering, or biochemical reaction of various dielectric materials such as food.

Sectional drawing seen from the front of the microwave heating device which concerns on one embodiment of this invention A-A 'sectional view of the microwave heating apparatus of FIG. B-B 'sectional view of the microwave heating apparatus of FIG. (A) The figure for demonstrating the data processing of the infrared sensor of the microwave heating apparatus of FIG. 1 (b) The figure for demonstrating the data processing of the infrared sensor of the microwave heating apparatus of FIG. The figure which shows the block division example of C-C 'sectional drawing of the microwave heating apparatus of FIG.

Explanation of symbols

31 Microwave heating device 32 Magnetron (microwave generation means)
33 Waveguide 34 Heating chamber 35 Mounting table 36 Heated object storage space 37 Antenna space 38, 39 Rotating antenna 40, 41 Motor (driving means)
42 Heating chamber bottom surface 43, 44 Coupling hole 45, 46 Coupling part 47, 48 Radiation part 53, 54 Bending part 55, 56, 57, 58 End part 59 Infrared sensor (temperature detection means)
60 Control part (control means)
61 Memory 62 Setting part 63 Door

Claims (4)

Microwave generating means, a rotating antenna that radiates microwaves from the microwave generating means to the heating chamber, a driving means that rotationally drives the rotating antenna, and a direction of the rotating antenna by controlling the driving means And the rotating antenna has a portion having a strong radiation directivity, and the control means causes the portion having a strong radiation directivity of the rotating antenna to be directed to a predetermined location, and performs local concentrated heating. A microwave heating apparatus configured to swing a portion having a strong radiation directivity of the rotating antenna several times during the local concentrated heating. Microwave generation means, a waveguide for transmitting microwaves from the microwave generation means, a heating chamber connected to the waveguide, and a placement placed in the heating chamber for placing an object to be heated A heating table, a space for storing an object to be heated formed above the mounting table in the heating chamber, an antenna space formed below the mounting table in the heating chamber, and a microwave in the waveguide are heated. A rotating antenna having radiation directivity disposed in the antenna space from the waveguide for radiating indoors, a driving means for driving the rotating antenna to rotate, and a direction of the rotating antenna by controlling the driving means Control means for controlling, and the control means performs local concentrated heating with a strong radiation directivity portion of the rotating antenna directed to a predetermined location, and the rotation at the time of the local concentrated heating. Microwave heating apparatus radiation directivity of a strong site was constructed to Sudo swinging the container. The heating chamber is formed in a horizontally long shape that is long in the width direction with respect to the depth, a plurality of rotating antennas are provided along the width direction of the heating chamber, and the control means rotates the plurality of rotating antennas to cover the heating chamber. The structure according to claim 1 or 2, wherein at least one portion having a strong radiation directivity among the plurality of rotating antennas is locally heated toward a predetermined location. Microwave heating device. The microwave heating apparatus according to any one of claims 1 to 3, wherein the control means swings the rotating antenna to be swung within a range of 10 degrees or less.