JP2008170076A - Microwave heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microwave heating device realizing local concentrated heating in response to a purpose while realizing uniform heating of a heating chamber whole in a normal time, and capable of illustrating a heating area in the heating chamber in a display means. <P>SOLUTION: The microwave heating device has plural rotating antennas 38, 39 for radiating microwaves, driving means 40, 41 for driving rotation of the rotating antennas, a home position detecting means 36, a temperature distribution detecting means 10 for detecting a temperature distribution in the heating chamber, a control means 411 for controlling microwave generating means and the driving means, and the display means 112 for displaying a heating area in the heating chamber. In the control means, in at least one of the rotating antennas of the plural rotating antennas, a portion with strong radiation directivity is controlled in a direction determined based on a detection result of the temperature distribution detecting means. It is composed to separately display states of when the plural rotating antennas are rotating together, and when at least one of the rotating antennas is stopped. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  The microwave oven, which is a typical microwave heating device, can directly heat food, which is a typical object to be heated, and is an indispensable device in daily life with the simplicity that does not require the preparation of a pan or pot. ing. Up to now, microwave ovens have a space for storing food in a heating chamber through which microwaves propagate, and the width and depth dimensions are approximately 300 to 400 mm, and the height dimension is approximately 200 mm. However, it is popular.

  In recent years, the bottom of the space for storing foods has been flattened, and the width has a width of at least 400 mm, which is relatively larger than the depth. Products with shapes have been put into practical use.

  By the way, the wavelength of the microwave used by the microwave oven is about 120 mm, a strong electric field distribution (hereinafter referred to as radio wave distribution) is generated in the heating chamber, and the influence of the shape of the object to be heated and its physical characteristics It is known that heating unevenness occurs due to synergy. In particular, in the heating chamber having a large dimension in the width direction described above, it is necessary to increase the uniformity of heating more than before in order to simultaneously heat foods placed on a plurality of tableware.

  Conventionally, this type of microwave heating apparatus is provided with one radiation antenna and rotationally drives the antenna, but it has been difficult to locally heat the central portion of the heating chamber. Therefore, as a measure for improving the uniformity of heating, one provided with a plurality of radiation antennas or one provided with a plurality of high-frequency stirring means has been proposed (see Patent Document 1).

  However, even if the interior is large, it does not always heat a large amount of food. For example, when warming a full mug of milk, it is considered more efficient to concentrate only on milk without heating the entire interior uniformly. .

  Even when heating multiple foods at the same time, if there is a difference in the temperature of the food, such as 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's like a box lunch box, it contains foods (pickles, salads, desserts, etc.) that you don't want to heat in one container, and intensively heats only the foods (rice, side dishes, etc.) that should be heated. 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 reason, there has been proposed one that performs central heating by switching a plurality of radiation antennas and controlling the stop position (see Patent Document 2).
JP 2004-259646 A Japanese Patent No. 3617224

With reference to Patent Documents 1 and 2, first, if the heating chamber has a wide width, it is likely that uniform heating of the entire heating chamber can be realized by configuring a plurality of radiation antennas on the left and right. Concentrated heating locally can be concentrated to some extent in the direction of the tip of the unipole antenna by stopping the radiation antenna, for example. However, the problem is how much it can be concentrated, and it is usually difficult to achieve local concentrated heating according to the purpose while achieving uniform heating throughout the heating chamber. there were.

  The present invention has been made in order to solve the above-mentioned problems. Usually, while achieving uniform heating of the entire heating chamber, local concentrated heating is also realized according to the purpose, and this state is recognized by the user. An object of the present invention is to provide a microwave heating apparatus that can be used.

  In order to achieve the above object, a microwave heating apparatus of the present invention comprises a microwave generating means, a waveguide for transmitting microwaves from the microwave generating means, and heating for housing an object to be heated by the microwave. A plurality of rotating antennas for radiating the microwave from the waveguide to the heating chamber, driving means for rotating the rotating antennas, and each rotating antenna being at a predetermined origin angle Origin detecting means for detecting, temperature distribution detecting means for detecting a temperature distribution in the heating chamber, and control means for controlling the microwave generating means and the driving means, wherein the control means comprises the plurality of rotations. A radio wave control mode for controlling at least one rotating antenna of the antennas in a direction determined based on a detection result of the temperature distribution detecting means, a portion having a strong radiation directivity; A microwave heating apparatus having an origin detection mode for rotating each rotary antenna until an origin signal is input from the origin detection means, and the control unit further rotates the rotary antenna from the origin detection by the origin detection means. The angle is detected and the rotation state of the rotating antenna is displayed on the display means.

  As a result, the microwave heating apparatus of the present invention directs the portion having a strong radiation directivity of the rotating antenna to the low temperature portion of the temperature of each detection region detected by the temperature distribution detecting means, and the temperature difference between the low temperature portion and the high temperature portion is reduced. It can be controlled to be small, and the rotational position of the rotating antenna can be displayed in accordance with the angle from where the origin of the rotating antenna is detected.

  The microwave heating apparatus according to the present invention can realize local concentrated heating in which the temperature difference between the low temperature portion and the high temperature portion is reduced as well as uniform heating of the entire heating chamber, and the user can know the heating status.

  According to a first aspect of the present invention, there is provided a microwave generation means, a waveguide that transmits microwaves from the microwave generation means, a heating chamber that houses an object to be heated by the microwave, and the waveguide A plurality of rotating antennas for radiating the microwaves to the heating chamber; driving means for rotationally driving the rotating antennas; origin detecting means for detecting that each rotating antenna is at a predetermined origin angle; and the heating Temperature distribution detecting means for detecting a temperature distribution in the room, and control means for controlling the microwave generating means and the driving means, wherein the control means includes at least one rotating antenna among the plurality of rotating antennas. A radio wave control mode for controlling a portion having a strong radiation directivity in a direction determined based on a detection result of the temperature distribution detection means, and an origin signal from the origin detection means. A microwave heating apparatus having an origin detection mode for rotating each of the rotating antennas until the control unit further detects the rotation angle of the rotating antenna from the origin detection by the origin detecting means to rotate the rotating antenna It is configured to display the situation on the display means, and the part with strong radiation directivity of the rotating antenna is directed to the low temperature part of the temperature of each detection area detected by the temperature distribution detection means, and the temperature difference between the low temperature part and the high temperature part is Since it can be controlled to be small, uniform overheating is possible and local concentrated overheating can be realized, and furthermore, the rotation position of the rotating antenna can be displayed according to the angle from where the origin of the rotating antenna was detected, The user can always know the heating status and can feel secure.

  In the second aspect of the invention, the display unit displays a display that is an image of a rotating antenna in accordance with the number of rotating antennas, and performs a control for distinguishing and reporting the movement of each rotating antenna during rotation and when stopped. In this way, it is possible to provide a microwave heating apparatus that can grasp the operation status of each of the plurality of rotating antennas, always know which part of the food is heated, and give the user a sense of security.

  According to a third aspect of the invention, the display means has a display in which the heating chamber is imaged, and the display is such that the heating chamber is uniformly heated while the rotating antenna is rotating, and locally during the stop. It is designed to display the area that is being heated, and it is possible to provide a microwave heating device that can always grasp which part of the heating chamber is concentrated and that gives the user a sense of security. .

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
1 to 3 show a configuration of a microwave oven that is a typical microwave heating apparatus according to the present invention, FIG. 1 is a configuration diagram showing a cross section viewed from the front, and FIG. 2 is a cross section taken along line AA ′ of FIG. FIG. 3 and FIG. 3 are cross-sectional views taken along the line BB ′ of FIG.

  As shown in FIG. 1, a microwave oven 31 includes a waveguide 33 that transmits a microwave radiated from a magnetron 32 that is a typical microwave generation unit, and a width dimension that is connected to the upper portion of the waveguide 33. (About 410 mm) is larger than the dimension in the depth direction (about 315 mm), and is fixed in the heating chamber 34 for placing food (not shown) as a typical object to be heated. Since it is made of a low-loss dielectric material such as glass, a mounting table 35 having a property that microwaves can be easily transmitted, an antenna space 37 formed below the mounting table 35 in the heating chamber 34, and the waveguide 33 In order to radiate microwaves into the heating chamber 34, two rotating antennas 38 and 39 that are mounted symmetrically with respect to the width direction of the heating chamber 34 from the waveguide 33 to the antenna space 37, and rotated Motors 40 and 41 as typical driving means capable of rotating the antennas 38 and 39, control means 411 for controlling the motors 40 and 41 to control the orientation of the rotating antennas 38 and 39, and the respective rotating antennas 38 and 39 A photo interrupter 36 that constitutes an origin detection mechanism for detecting the origin of rotation, and an infrared sensor 10 that is a temperature distribution detecting means for detecting a temperature distribution in the heating chamber 34.

  The microwave oven 31 includes a door 64 as shown in FIG. A setting unit 63 is disposed below the door 64. The setting means 63 allows the user to select various cooking menus according to food and cooking contents. Based on the selection result, the control unit 411 can control the magnetron 32 and the motors 40 and 41.

  The rotating antennas 38 and 39 have a radiation directivity. The microwave oven 31 of the first embodiment is configured to centrally heat a specific food by controlling at least one of the rotating antennas 38 and 39 with a strong radiation directivity in a predetermined direction. The specific control method will be described later.

  The rotating antennas 38 and 39 are electrically conductive in a substantially cylindrical shape with a diameter of about 18 mm that penetrates the coupling holes 43 and 44 with a diameter of about 30 mm provided at the boundary surface between the waveguide 33 and the bottom surface 42 of the heating chamber. The coupling portions 45 and 46 made of a conductive material are integrated with the upper ends of the coupling portions 45 and 46 by caulking, welding, or the like, and are made of a conductive material having a larger area in the horizontal direction than the vertical direction. And radiating portions 47 and 48.

The rotating antennas 38 and 39 are configured to be fitted to the shafts 49 and 50 of the motors 40 and 41 so that the centers of the coupling portions 43 and 44 are the centers of rotational driving. The radiating portions 47 and 48 have a radiation directivity because the shape is not constant with respect to the direction of rotation.

  The centers of rotation of the rotating antennas 38 and 39 are arranged at an approximately equal distance from the center in the heating chamber 34. With this configuration, it is possible to heat the vicinity of the center of the heating chamber, which is normally difficult to heat with a single antenna configuration, by directing the portions of the rotary antennas 38 and 39 having strong radiation directivity to the vicinity of the center.

  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 with respect to the width direction of the heating chamber 34, so that the microwaves radiated from the magnetron 32 are almost evenly distributed in the heating chamber 34 via the waveguide 33 and the rotating antennas 38 and 39. Distributed.

  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 the microwave radiation to the outside of the two sides is limited. 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 length from the center of the coupling portion is about 75 mm. Constitutes end portions 57 and 58 of about 55 mm. In addition, the dimension in the width direction of the end portion 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.

  In the case of heating a general food uniformly in this configuration, it is not necessary to pay particular attention to the place of placement as in the case of a conventional microwave oven, and the rotating antennas 38 and 39 may be rotated at a constant speed as in the conventional case.

  On the other hand, in the case of central heating, when the vicinity of the center in the heating chamber 34 is heated, the control means 411 sets the end portions 57 and 58 of the rotating antennas 38 and 39 to the width of the heating chamber 34 as shown in FIG. Control is performed so as to be directed in a predetermined direction, that is, approximately the center of the direction and approximately the center of the depth direction. When the end portions 57 and 58 of the rotating antennas 38 and 39 are directed to the approximate center in the width direction of the heating chamber 34 and the approximate center in the depth direction, the radiation directivity in the direction of the end portions 57 and 58 is strong. Microwaves are radiated from the directions 57 and 58, and the food located in that direction can be intensively heated.

  Further, when heating the vicinity of the left side in the heating chamber 34, as shown in FIG. 5, the control means 411 faces the ends 57 and 58 of the rotating antennas 38 and 39 to the left (the heating chamber 34 is viewed from the door 64 side). To the left). When the end portions 57 and 58 of the rotating antennas 38 and 39 both face the left side when the heating chamber 34 is viewed from the door 64 side, each antenna has a strong radiation directivity in the direction of the end portions 57 and 58. In particular, microwaves are emitted from the direction of the end portions 57 and 58, and the food located in that direction can be intensively heated.

  Similarly, when the vicinity of the right side in the heating chamber 34 is heated, as shown in FIG. 6, the control means 411 turns the end portions 57 and 58 of the rotating antennas 38 and 39 to the right (the heating chamber 34 from the door 64 side). Control to turn to the right). When both ends 57 and 58 of the rotating antennas 38 and 39 face the right side when the heating chamber 34 is viewed from the door 64 side, each antenna has a strong radiation directivity in the direction of the ends 57 and 58. Microwaves are emitted from the direction of the ends 57 and 58, and the food located in that direction can be intensively heated.

  In addition, when the vicinity of the front center in the heating chamber 34 is heated, as shown in FIG. 7, the control means 411 connects the end portions 57 and 58 of the rotating antennas 38 and 39 to the substantially center in the width direction of the heating chamber 34. Control is made so as to be directed forward in the depth direction (near the center front in the heating chamber 34). As shown in FIG. 7, when the end portions 57 and 58 of the rotating antennas 38 and 39 are directed near the center front in the heating chamber 34, each antenna has a strong radiation directivity in the direction of the end portions 57 and 58. Particularly, microwaves are radiated from the direction of the end portions 57 and 58, and the food located in that direction can be heated intensively.

  In addition, when the vicinity of the rear center in the heating chamber 34 is heated, as shown in FIG. 8, the control means 411 connects the end portions 57 and 58 of the rotating antennas 38 and 39 to the substantially center in the width direction of the heating chamber 34. Control is performed so as to be directed rearward in the depth direction (near the central rear in the heating chamber 34). As shown in FIG. 8, when the end portions 57 and 58 of the rotating antennas 38 and 39 face the vicinity of the center rear in the heating chamber 34, each antenna has a strong radiation directivity in the direction of the end portions 57 and 58. Particularly, microwaves are radiated from the direction of the end portions 57 and 58, and the food located in that direction can be heated intensively.

  In this embodiment, the control means 411 controls the orientations of both the rotating antennas 38 and 39, but any one of them may be used.

  As described above, the microwave oven 31 of the first embodiment controls the direction of the rotating antenna in accordance with the location where it is desired to locally heat, and in order to point the rotating antennas 38 and 39 in a predetermined direction. Further, a stepping motor may be used as the motors 40 and 41, or a means for detecting the reference position and controlling the energization time even with a constant rotation motor can be considered.

  In the microwave oven 31 of the first embodiment, stepping motors are used as the motors 40 and 41, and origin detection mechanisms are provided on the shafts 40 and 41 of the respective motors. FIG. 9 is a cross-sectional view taken along the line D-D ′ of FIG. 1, and this origin detection mechanism includes a disc 36 a having a shaft as a central axis and a photo interrupter 36 as shown in FIG. 9. The circular plate 36a is provided with a rectangular slit 36b.

  The disc 36a is commonly attached to the shafts of the motor shafts 49 and 50 for rotating the rotary antennas 38 and 39, and rotates so as to block the optical path of the photo interrupter 36 including a light emitting element and a light receiving element. Is.

  With this configuration, when the slit 36b passes through the optical path of the photointerrupter 36, there is nothing to block the optical path, so that the passage time of the slit can be detected. Therefore, by setting the position of the slit 36b as the origin of the rotating antennas 38 and 39, the origin of the rotating antenna can be detected by the photo interrupter 36 attached to each motor.

  Further, the control means 411 uses the origin that can be detected by the origin detection mechanism as a reference, and determines the angle (stop position) of the rotating antennas 38 and 39 when the highly directional portions of the rotating antennas 38 and 39 are concentrated on the local heating location. An antenna angle storage unit is stored in advance. When local heating is performed by controlling the operation of the rotating antennas 38 and 39, information in the antenna angle storage unit is referred to.

In addition, although the case where there are two rotating antennas has been described so far, the number of rotating antennas is not limited to this, and may be two or more. For example, as illustrated in FIG. It is good also as a structure. In the state shown in FIG. 10, the end portions of the respective rotating antennas face the vicinity of the center in the heating chamber, and the food located near the center can be intensively heated.

  Next, with reference to FIG. 11, the temperature detection means with which the microwave oven 31 of this Embodiment 1 is provided is demonstrated. This temperature detection means includes a plurality of infrared detection elements 13 arranged in a line on the substrate 19, a case 18 that houses the entire substrate 19, and a case 18 that is perpendicular to the direction in which the infrared detection elements 13 are aligned. And a stepping motor 11 that moves in the intersecting direction.

  On the substrate 19, a metal can 15 enclosing the infrared detection element 13 and an electronic circuit 20 for processing the operation of the infrared detection element are provided. The can 15 is provided with a lens 14 through which infrared rays pass. Further, the case 18 is provided with an infrared passage hole 16 through which infrared light passes and a hole 17 through which a lead wire from the electronic circuit 20 passes.

  With this configuration, when the stepping motor 11 rotates, the case 18 can be moved in a direction perpendicular to the direction in which the infrared detection elements 13 are aligned.

  FIG. 13 is a diagram illustrating an infrared temperature detection spot in the C-C ′ cross section in FIG. 1. As shown in the figure, the microwave oven 31 of the first embodiment can detect the temperature distribution in almost all regions in the heating chamber 34 by the reciprocating rotation of the stepping motor 11 of the temperature detecting means. Is.

  Specifically, for example, first, the temperature detection elements 13 (for example, infrared sensors) arranged in a line of the temperature detection means simultaneously detect the temperature distribution in the areas A1 to A4 in FIG. Next, when the stepping motor 11 rotates and the case 18 moves, the temperature detection element 13 detects the temperature distribution in the region of B1 to B4. Furthermore, when the stepping motor 11 rotates and the case 18 moves, the temperature detection element 13 detects the temperature distribution in the region C1 to C4, and similarly detects the temperature distribution in the region D1 to D4.

  In addition, the temperature distribution is detected in the order of C1 to C4, B1 to B4, and A1 to A4 from the region side of D1 to D4 by the reverse rotation of the stepping motor 11 following the above operation. The temperature distribution detecting means can detect the entire temperature distribution in the heating chamber 34 by repeating the above operation.

  Next, a schematic configuration of the control unit 411 will be described with reference to FIG. The control unit 411 includes a radio wave control mode 411a and an origin detection mode 411b. The radio wave control mode 411a includes an antenna control unit 101 that controls the operation of the rotating antennas 38 and 39, a food determination unit 102 that determines whether the object to be heated placed in the heating chamber 34 is food, or the like. The heating initial stage end determination unit 103 that determines the end of the initial stage of the heating process and the heating end determination unit 104 that determines the end of the entire heating process are included.

  The food determination unit 102 includes an initial temperature distribution storage unit 108 that stores an initial temperature distribution of an object to be heated, and a temperature increase rate calculation unit 109 that calculates a temperature increase rate per unit time of the object to be heated. When the calculated temperature increase rate is equal to or higher than a predetermined value, it is determined that the object to be heated is food. In other words, it is determined whether the region where the temperature is detected is a mounting table on which an object to be heated is placed or a food to be heated. This is because the mounting table transmits microwaves and hardly rises in temperature, but the food easily absorbs microwaves and rises in temperature.

Alternatively, with reference to the initial temperature distribution at the start of heating, if there is a region having a temperature equal to or lower than a predetermined temperature, the object to be heated is determined to be food. In other words, it is assumed that a large amount of frozen foods causes a gradual rise in temperature, and therefore food cannot be determined based on the temperature rise value.

  The heating initial stage end determination unit 103 performs heating when, for example, a determination condition for determining that the heating initial stage has ended when a predetermined time has elapsed from the start of heating, or when the maximum temperature of the object to be heated reaches a predetermined temperature or higher. The heat treatment is performed using the determination condition for determining that the initial stage has been completed, and the determination condition for determining that the initial stage of heating has been completed when the maximum value of the temperature change of the heated object from the start of heating is equal to or greater than a predetermined value. It is determined that the initial stage has been completed.

  The heating end determination unit 104 determines, for example, a determination condition for determining that the heating process is to be ended when the maximum temperature in the temperature distribution of the object to be heated exceeds a preset set temperature, or the average temperature of the portion determined to be food. Measure conditions for ending the heat treatment when the set temperature is exceeded, and the time required for the maximum temperature of the object to be heated to reach a predetermined temperature, and measuring a certain percentage of the required time (for example, 50% ) As an additional heating time, and then the end of the heating process is determined by a configuration that ends the heating process when the additional heating time ends.

  The antenna control unit 101 controls the operation of the rotating antennas 38 and 39 to control the operation of the rotating antennas 38 and 39 to uniformly heat the heating chamber, and the operation of the rotating antennas 38 and 39 to heat the low temperature portion of the object to be heated. The local heating (spot heating) mode control unit 106 and the low temperature part extraction unit 107 that detects the low temperature part of the object to be heated placed in the heating chamber.

  For example, the distributed heating mode control unit 105 performs distributed heating by changing the stop positions of the two rotary antennas 38 and 39 that can be locally heated by stopping at a predetermined position during microwave oscillation. In this configuration, distributed heating is realized by continuously rotating the rotating antennas 38 and 39, and distributed heating is realized by randomly changing the stop positions of the rotating antennas 38 and 39.

  The local heating mode control unit 106 is configured to obtain information on the lowest temperature location from the low temperature part extraction unit 107 and control the direction of the rotating antennas 38 and 39 to perform local heating. For example, if the lowest temperature point is any one of B2, B3, C2, and C3 in FIG. 12, the rotating antenna 38, 39 is in the direction in which the rotating antennas 38 and 39 heat the center, that is, in the stop position shown in FIG. 39 is stopped.

  If the lowest temperature point is either B1 or C1 in FIG. 12, the rotating antennas 38 and 39 are stopped in the direction in which the rotating antennas 38 and 39 heat in the left direction, that is, in the stop position shown in FIG. Let Further, if the lowest temperature point is any of B4 and C4 in FIG. 12, the rotating antennas 38 and 39 are stopped in the direction in which the rotating antennas 38 and 39 heat in the right direction, that is, in the stop position shown in FIG. Let

Also, if the lowest temperature location is one of A2 and A3 in FIG. 12, the rotating antennas 38 and 39 are stopped in the direction in which the rotating antennas 38 and 39 heat the front, that is, in the stop position shown in FIG. . If the lowest temperature location is either D2 or D3 in FIG. 12, the rotating antennas 38 and 39 are stopped in the direction in which the rotating antennas 38 and 39 heat the rear, that is, in the direction shown in FIG. If the lowest temperature location is A1, the rotating antennas 38 and 39 are stopped in a direction in which the rotating antennas 38 and 39 heat the left front direction. If the lowest temperature location is A4, the rotating antennas 38 and 39 are stopped in a direction in which the rotating antennas 38 and 39 heat the right front direction. If the lowest temperature location is D1, the rotating antennas 38 and 39 are stopped in a direction in which the rotating antennas 38 and 39 heat the left rear direction. If the minimum temperature location is D4, the rotating antenna 3
The rotating antennas 38 and 39 are stopped in a direction in which 8, 39 heats the right rear direction.

  However, if the temperature difference between the highest temperature location and the lowest temperature location is small (for example, the temperature difference is within 5 ° C.), the transition to the local heating mode is prohibited. This is to prevent unnecessarily going back and forth between the distributed heating mode and the local heating mode.

  The local heating mode control unit 106 of the radio wave control mode 411a has a certain temperature difference between the detected temperature at the lowest temperature position and the highest temperature in the region where the temperature of the other object to be heated is detected in the above-described local heating mode. When the temperature is reduced to (for example, 2 ° C.), the mode is shifted to the dispersion heating mode.

  The radio wave control mode 411a controls the stop position of the rotating antennas 38 and 39 according to the lowest temperature point detected by the temperature detecting means. At this time, the rotating antenna remains stopped at a predetermined position. If microwaves continue to be radiated into the heating chamber, the rotating antenna itself may become too hot and melt.

  In view of this point, the local heating mode control unit 106 of the radio wave control mode 411a includes a stop upper limit time storage unit that stores in advance an upper limit time during which the rotating antennas 38 and 39 are allowed to stop in the local heating mode described above. , A stop time counting unit that counts the time when the rotating antenna is stopped, and when the time when the rotating antenna is stopped reaches the antenna stop upper limit time, the local heating mode is forcibly canceled, It is assumed that the mode is shifted to the distributed heating mode.

  In addition, when shifting from the local heating mode to the distributed heating mode, there is a minimum temperature location, and when that location is a location where the rotating antenna is stopped even in the previous local heating mode, local heating for a long time in one location In view of the danger that the rotating antenna itself becomes an abnormal temperature, the local heating mode transition grace time of a predetermined time is provided so as not to immediately shift to the local heating mode.

  On the other hand, the origin detection mode 411b is a mode in which the origin is detected based on a signal from the photo interrupter 36. The angle at which the input of the received light can be confirmed by receiving the signal from the photo interrupter 36 while rotating the motors 40 and 41. Is stored as the origin.

  During the origin detection mode, the angles of the rotating antennas 38 and 39 cannot be specified. If the microwaves are oscillated as they are, an unintentional heating state may be caused and a defect may be caused. Therefore, the control unit 411 switches between the radio wave control mode and the origin detection mode, and performs control to stop the operation of the magnetron while driving the rotating antenna in the origin detection mode.

The origin detection may be performed once after the power is turned on. However, since the angle may be gradually shifted due to a motor slip or the like, the control unit 411 performs the origin detection mode after the heating process is completed. , Wait for non-heating with the origin detected. As a result, the origin can be adjusted again for each heat treatment, and it is possible to prevent the waiting time for the origin detection from occurring before the heat treatment is started. However, since the origin is not detected before the first heating process after turning on the power, the origin is detected first after the power is turned on, and the origin is detected before the first heating. By waiting at the time of non-heating, it is possible to prevent waiting time for detecting the origin before starting the heat treatment.

  If the origin cannot be detected, the motors 40 and 41 that drive the rotating antennas 38 and 39 may be out of order, and it is dangerous to operate the rotating antennas 38 and 39 in this state. The operations of the antennas 38 and 39 are stopped.

  In addition, the control means 411 uniformly heats the entire heating chamber 34 in the distributed heating mode at the initial stage of heating start, and shifts to the local heating mode when a difference in the temperature distribution in the heating chamber 34 begins to occur. Also good. Since there is no difference in the temperature distribution in the heating chamber 34 at the initial stage of heating, the distributed heating mode can efficiently raise the temperature of the entire heating chamber 34.

  Further, in the initial stage of starting heating, the control unit 411 may first locally heat the vicinity of the center in the heating chamber 34. Normally, when the heat treatment is started from a state where there is no difference in temperature distribution in the heating chamber, the temperature in the vicinity of the center of the heating chamber is most difficult to increase. Therefore, the entire heating chamber can be uniformly heated efficiently by first locally heating the vicinity of the center in the heating chamber 34 and then performing distributed heating to uniformly heat the entire heating chamber.

  Now, in such a microwave oven, as shown in FIG. 13, the control means 411 includes an antenna angle storage unit 111 that receives a signal from the photo interrupter 36 and stores the rotation angles of the rotating antennas 38 and 39, and the antenna from the origin. I remember the angle. Then, based on the output from the antenna angle storage unit 111, the antenna rotation state is displayed on the display unit 112 which is a display means for displaying menu setting contents, cooking time, etc. provided in the operation unit 63 shown in FIG. It is. The antenna angle display has been described as an example based on the output from the antenna angle storage means. However, the present invention is not limited to this, and any configuration that can display the rotation angle from the origin is possible. It may be.

  The display unit 112 is composed of a display element such as an LCD, an LED, or a fluorescent display tube, and shows a display as shown in which region of the heating chamber is heated by the rotating antenna. Alternatively, a direction in which a portion having a strong radiation directivity of the rotating antenna faces may be illustrated. By providing such a display, the user can grasp which position of the food is being heated and can recognize the progress of the heating.

  FIG. 14 illustrates an LCD as an example of a display element. There are two semicircular dots arranged horizontally in the center of the figure. This round dot is a schematic representation of the power supply opening. By displaying three rows of marks separated in three directions on top of each semicircle in sequence, the state of radio waves being emitted is shown. It represents.

  As shown in FIG. 15, the display method in the distributed heating mode is as follows. First, a semicircular point is lit (S1), and the first column is lit in two semicircular points and three directions each (S2). The first and second columns are lit in two semicircular points and three directions each (S3), and the first, second and third columns are lit in two semicircular points and three directions each. (S4) Subsequently, it is assumed that the process returns to step S1, and thereafter the display is periodically changed in the same procedure.

  The manner of display in the local heating mode is carried out as shown in FIGS.

  The display at the time of locally heating any one of A1, B1, C1, and D1 shown in FIG. 12 will be described with reference to FIG. First, semicircular points are lit (S5), two semicircular points and one column in each left hand direction are lit (S6), two semicircular points and the first column in each left hand direction, and The second column is lit (S7), the two semicircular points and the first column in each left hand direction, and the second and third columns are lit (S8), and then the process returns to step S5. The display changes periodically.

Next, with reference to FIG. 17, the display when locally heating the central portion of the heating chamber, that is, any of A2, B2, C2, D2, A3, B3, C3, and D3 shown in FIG. 12 will be described. First, semicircular points are lit (S9), two semicircular points and one central row are lit (S10), the two semicircular points and the first and second rows in the middle are the same. The column is lit (S11), the two semicircular points and the center first column and the second column and the third column of each are lit (S12), and then the process returns to step S9. Transitions periodically.

  Further, FIG. 18 will be used to explain the display when locally heating one of A4, B4, C4 and D4 shown in FIG. First, semicircular points are lit (S13), two semicircular points and one column in each right hand direction are lit (S14), two semicircular points and the first column in each right hand direction, and The second column is lit (S15), the two semicircular points and the first column in each right hand direction, and the second and third columns are lit (S16), and then the process returns to step S13. The display changes periodically.

  In this way, the display that represents the rotating antenna is displayed according to the number of rotating antennas, and when each rotating antenna is in a uniform heating state, an image that spreads the microwaves evenly in all directions is displayed. The display is made to display, and during the local heating, the display is made by distinguishing and displaying the image that heats up concentrating on one direction.

  In this description, the heating chamber is divided into three areas (left, center, and right) for display, but there is no need to specialize the three, and the display may be distinguished by an arbitrary number of areas. In addition, here, it is described that the marks of the three columns are sequentially displayed, but it is not particularly necessary to have three columns, and the number of columns can be arbitrarily selected. Here, the three columns are described as being sequentially lit, but the columns to be displayed can be made variable according to the output of the microwave. In addition, the display is made according to the number of the plurality of rotating antennas, but the number to be displayed does not have to be matched to the number of antennas. That is, the content and shape to be displayed are not specified as long as the above object can be achieved.

  In addition, as shown in FIG. 19, if the display element is provided with a square frame representing the image in the heating chamber and a display indicating a region to be locally heated is disposed, the rotating antenna is being heated uniformly using them. If there is, it is possible to display all the areas, such as blinking, or sequentially lighting from the center to the outer periphery, reminiscent of the image of uniformly heating the heating chamber. . At the time of local heating, only the region that is locally heated is turned on or blinked to highlight the region that is locally heated.

  The content and shape to be displayed are not specified if the above purpose can be achieved.

  As described above, the present invention can control a portion having a high radiation directivity of a rotating antenna disposed in a heating chamber in a predetermined direction to centrally heat a specific object to be heated. The rotation state can be displayed, and it can be applied to uses such as heating, thawing, ceramic heating, drying, sintering, or biochemical reaction of various dielectric materials such as food.

The block diagram which shows the front cross section of the microwave heating device of Embodiment 1 of this invention The block diagram which shows the side cross section of the same microwave heating device (A-A 'sectional drawing in FIG. 1) The block diagram which shows the plane cross section of the same microwave heating apparatus (B-B 'sectional drawing in FIG. 1) The figure explaining the direction of the rotating antenna when locally heating around the center of the heating chamber The figure explaining the direction of the rotating antenna when locally heating the left side of the heating chamber The figure explaining the direction of the rotating antenna when locally heating the right side of the heating chamber The figure explaining the direction of the rotating antenna when locally heating the front of the heating chamber The figure explaining the direction of a rotation antenna when heating the back of a heating chamber locally The figure explaining the origin detection mechanism of a rotating antenna (D-D 'sectional view in Drawing 1) Plane cross-sectional view of a microwave heating device having three rotating antennas Schematic cross-sectional configuration diagram of temperature distribution detection means The figure explaining the infrared temperature detection spot in the C-C 'cross section in FIG. Schematic configuration diagram of control means The figure which shows the example of the display contents of the display means Figure showing example of display contents in uniform heating mode The figure which shows the example of a display content at the time of locally heating the heating chamber left side in local heating control mode The figure which shows the example of a display content at the time of locally heating the heating chamber center part in local heating control mode The figure which shows the example of a display content at the time of locally heating the right side of the heating chamber in local heating control mode The figure which shows the example of a display content in the other example of a display means

Explanation of symbols

10 Temperature sensor (temperature detection means)
31 Microwave oven (microwave heating device)
32 Magnetron (microwave generation means)
33 Waveguide 34 Heating chamber 35 Mounting table 36 Origin detection means 37 Antenna space 38, 39, Rotating antennas 40, 41 Motor (drive means)
411 Control means 411a Radio wave control mode 411b Origin detection mode

Claims (4)

A microwave generating means; a waveguide for transmitting microwaves from the microwave generating means; a heating chamber for storing an object to be heated by the microwave; and the microwave from the waveguide to the heating chamber. A plurality of rotating antennas for radiating the rotating antenna, driving means for rotationally driving the rotating antennas, origin detecting means for detecting that each rotating antenna is at a predetermined origin angle, and detecting a temperature distribution in the heating chamber Temperature distribution detecting means, and control means for controlling the microwave generating means and the driving means, wherein the control means has at least one rotating antenna among the plurality of rotating antennas having strong radiation directivity. The radio wave control mode for controlling the part in the direction determined based on the detection result of the temperature distribution detection means, and each time until the origin signal is input from the origin detection means. A microwave heating apparatus having an origin detection mode for rotating an antenna, and the control unit further detects a rotation angle of the rotary antenna from the origin detection by the origin detection means and displays a rotation status of the rotation antenna A microwave heating device configured to be displayed on the screen. The control unit rotates the temperature of each detection region detected by the temperature distribution detection means so that the portion having a strong radiation directivity of the rotating antenna faces the low temperature portion until the temperature difference between the low temperature portion and the high temperature portion becomes small. In addition to performing control to stop the antenna, an antenna angle storage unit that stores an angle from the origin of the rotating antenna when a portion having a strong radiation directivity of the rotating antenna is directed to a specific region in the heating chamber is provided. The microwave heating apparatus according to claim 1, wherein the rotating state of the rotating antenna is displayed on a display unit so as to notify a user of a heated place in the heating chamber. The microwave according to claim 2, wherein the display means displays a display in the image of a rotating antenna in accordance with the number of the plurality of rotating antennas, and can separately notify the movement of each rotating antenna during rotation and when stopped. Heating device. The display means has a display in which the heating chamber is imaged. When the rotating antenna rotates, the display means that the heating chamber is heated uniformly. When the rotating antenna is stopped, the display means indicates a locally heated region. 4. The microwave heating apparatus according to claim 2, wherein display is performed.

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