JP2008157586A - Microwave heating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microwave heating apparatus that realizes partial intensive heating in accordance with an intended use while realizing uniform heating of an entire heating chamber at normal times. <P>SOLUTION: The microwave heating apparatus includes a plurality of rotating antennas 38, 39 for radiating microwaves, drive means 40, 41 for rotatingly driving the rotating antennas 38, 39, an original point detection means 36, a temperature distribution detection means 10 for detecting the temperature distribution inside the heating chamber, and a control means 41 for controlling a microwave generating means and the drive means 40, 41. The control means has a radio wave control mode 411a for controlling at least one of the plurality of rotating antennas 38, 39 to a direction where a portion with strong directionality is determined based on the detection result from the temperature distribution detection means, and an origin detecting mode 411b for rotating each of the rotating antennas 38, 39 until an original point signal is input from the original point detection means. The microwave generating means is stopped during each of the rotating antennas 38, 39 is driven in the original point detecting mode. <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. However, 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 having a plurality of radiation antennas or one having a plurality of high-frequency stirring means has been proposed (for example, 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 mug of milk, it is more efficient to concentrate microwaves only on milk without heating the entire interior uniformly. It is considered to be the target.

  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 purpose, there has been proposed a technique in which a plurality of radiation antennas are switched and central heating is performed by controlling a stop position (see, for example, Patent Document 2).
JP 2004-259646 A Japanese Patent No. 3617224

Referring 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-described problems, and it is intended to provide a microwave heating apparatus that normally achieves uniform heating of the entire heating chamber and also achieves local concentrated heating according to the purpose. Objective.

  The microwave heating apparatus of the present invention includes a microwave generating means, a waveguide that transmits microwaves from the microwave generating 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 microwave from a tube to the heating chamber, driving means for rotating the rotating antennas, and origin detecting means for detecting that each rotating antenna is at a predetermined origin position; A temperature distribution detecting means for detecting a temperature distribution in the heating chamber; and a control means for controlling the microwave generating means and the driving means, wherein the control means rotates at least one of the plurality of rotating antennas. A radio wave control mode for controlling the antenna in a direction determined based on the detection result of the temperature distribution detecting means, and a source from the origin detecting means. Has an origin detection mode for rotating the respective rotating antenna to input a signal in driving the respective rotating antennas by the origin detection mode is obtained by a structure for stopping the microwave generator.

  With this configuration, the radio wave control mode and the origin detection mode are used separately, and in the radio wave control mode, the temperature distribution is directed toward the direction that requires heating based on the detection result of the temperature distribution detection means so that the radiation antenna has a strong radiation directivity. In the origin detection mode, heating by the microwave is stopped because the direction of the rotating antenna is unknown.

  Using the radio wave control mode and the origin detection mode separately, when in the radio wave control mode, the temperature distribution can be controlled by directing the part with strong radiation directivity of the rotating antenna in the direction that requires heating based on the detection result of the temperature distribution detection means, Further, in the origin detection mode, since the direction of the rotating antenna is unknown and heating by the microwave is stopped, appropriate heating can be performed without heating an inappropriate portion. And normally, localized concentrated heating can be performed according to the objective, implement | achieving uniform heating of the whole heating chamber.

  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 position; and the heating A temperature distribution detecting means for detecting a temperature distribution in the room; and a 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 microwave radiation directivity in a direction determined based on the detection result of the temperature distribution detecting means, and an origin signal from the origin detecting means. Has an origin detection mode in which each of the rotating antennas is rotated until the signal is input, and the microwave generating means is stopped while driving each rotating antenna in the origin detecting mode. In the radio wave control mode, the temperature distribution can be controlled by directing the part with strong radiation directivity of the rotating antenna in the direction that requires heating based on the detection result of the temperature distribution detection means. In the detection mode, since the direction of the rotating antenna is not known, the heating by the microwave is stopped, so that an appropriate heating can be performed without heating an inappropriate portion.

  The second aspect of the invention is an angle that is a rotational position from the origin of the rotating antenna, particularly when the control means of the first aspect of the invention is directed at a portion having a strong radiation directivity of the rotating antenna with respect to a specific region in the heating chamber. An antenna angle storage unit is stored, and a portion having a strong radiation directivity of the rotating antenna is directed to a low temperature portion of the temperature of each detection region detected by the temperature distribution detection means, so that a temperature difference between the low temperature portion and the high temperature portion is This is the control to stop the antenna until it becomes small, and by this, the data detected in advance in the experiment is stored in the antenna angle storage unit as the angle that becomes the rotation position from the origin of the rotating antenna, thereby detecting the origin The low temperature portion can be locally heated with high accuracy by rotating the stored angle from the above position. Further, by heating the low temperature part intensively until the temperature difference from the high temperature part becomes small, it becomes possible to finish the temperature of the heated object more uniformly so as not to generate an extremely high temperature or low temperature part.

  In the third aspect of the invention, in particular, when the control means of the first or second aspect of the invention is directed at a portion having a strong radiation directivity of the rotating antenna to a low temperature portion of the temperature of each detection region detected by the temperature distribution detection means, When the predetermined time or more has elapsed, the antenna is controlled to rotate again, thereby reducing the food temperature rise in the centrally heated region and increasing the time during which the microwave is heated locally. Therefore, excessive heating due to the concentration of microwaves on a part of the rotating antenna can be prevented.

  In the fourth aspect of the invention, in particular, the control means according to any one of the second to third aspects is directed such that a portion having a strong radiation directivity of the rotating antenna is directed to a low temperature portion of the temperature of each detection region detected by the temperature distribution detection means. When the control for rotating the antenna again is performed, the control for directing the portion having the strong radiation directivity of the rotating antenna to the low temperature portion again is suppressed until a predetermined time elapses. When the temperature of the food increases, and when the temperature rises to a temperature with a small difference from the temperature of the food in other regions, the control of canceling the local heating is performed, so that the temperature unevenness of the food can be suppressed.

  According to a fifth aspect of the present invention, in particular, any one of the first to fourth aspects further includes display means for displaying menu setting contents, cooking time, etc. The location where the food is heated is notified to the user, so that it is possible to always know which portion of the food is heated, and to provide a microwave heating device that gives the user a sense of security.

  The sixth invention has a setting means for the user to select a heating menu or the like, particularly in the fifth invention, and when the user inputs a part that the user particularly wants to heat, the radiation directivity of the rotating antenna is specified at the designated part. By directing the microwave to intensively by designating the position where the food is placed, if you want to heat a small amount of food in a shorter time, A microwave heating apparatus capable of heating in a shorter time can be provided.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

(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 detection means for detecting the 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 are configured to have microwave 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, the length from the center of the coupling portion is about 75 mm, and the length from the center of the coupling portion. 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 of microwaves 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 (rotational 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 stored in advance as a stop position is provided. 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. 12 is a diagram illustrating an infrared temperature detection spot in the C-C ′ cross section of 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 unit 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 antennas 38 and 39 are in the direction in which the rotating antennas 38 and 39 heat the center, that is, in the stop position shown in FIG. Stop.

  If the lowest temperature location is any of B1 and 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. . Further, if the lowest temperature point is any one 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. .

  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 one of D2 and 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 lowest temperature location is D4, the rotating antennas 38 and 39 are stopped in a direction in which the rotating antennas 38 and 39 heat 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 degrees), 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 it becomes smaller (for example, 2 degrees), it is assumed that 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.

  In the operation unit 63, display elements such as an LCD, an LED, and a fluorescent display tube are arranged. By using them, it is assumed that a display showing which heating chamber the heating antenna is heating is displayed. Alternatively, the direction in which the portion having the strong radiation directivity of the rotating antenna faces may be represented by a diagram. 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. The content and shape to be displayed are not specified if the above purpose can be achieved.

  In addition, when an input device such as a switch or an encoder arranged in the operation unit 63 is used and heating is performed by selecting at least one of the regions in the heating chamber displayed on the display unit, the heating unit is arranged. A specific object to be heated can be centrally heated by controlling a portion having a strong radiation directivity of the rotating antenna to a designated region. From this, for example, if a portion of the lunch box that is particularly heated is designated and heated, the portion can be finished particularly hot. Moreover, if the place which does not want to be heated is removed from the selection, the food at that place is not heated so much. With such a configuration, it is possible to provide an easy-to-use heating apparatus that can specify whether to heat or not to heat depending on the ingredients when various ingredients are simultaneously heated.

  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. (Rotation position) is detected and stored as the origin.

  During the origin detection mode, the angle (rotational position) 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 cause a defect. 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 (rotation position) may be gradually shifted due to a slip of the motor or the like, the control unit 411 heats the origin detection mode. This is done after the process is completed, and waits for non-heating when the origin is 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 the power is turned on, the origin is first detected 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.

  Next, the operation of the microwave oven 31 according to the first embodiment will be described. First, the operation from the power-on to the initial heating stage will be described with reference to FIG.

  First, when power is turned on (S301), origin detection is performed in the origin detection mode 411b. When the origin detection is completed, the motor is set in the origin state and waits. At this time, for example, if the origin cannot be detected even if the motor is rotated once or more, it is stored that an error has occurred in the origin detection (S302). Next, it is determined whether or not the user gives an instruction to start heating, such as pressing a button. (S303) If there is no instruction to start heating, the determination in S303 is repeated until there is an instruction to start heating. If there is an instruction to start heating, the process proceeds to S304.

  In S304, it is determined whether or not an error has occurred when the origin is detected in S302. If there is no error, the magnetron 32 generates a microwave, and the microwave is transmitted into the heating chamber 34 via the waveguide. Then, heating is started (S304). At this time, the temperature distribution detection means detects the temperature distribution in the heating chamber 34 at the initial heating time, and the radio wave control mode 411a stores the detection result of the temperature distribution (S305).

  Next, in the radio wave control mode 411a, for example, the rotating antennas 38 and 39 are rotated at a constant speed in order to realize distributed heating (S306). After a predetermined time has elapsed, the temperature distribution detection means detects the temperature distribution in the heating chamber 34 again (S307).

  Then, the heating initial stage end determination unit 103 in the radio wave control mode 411a performs the temperature distribution in the heating chamber in the initial heating stage detected in the step of S305 and the temperature distribution in the heating chamber after the elapse of a certain time detected in the stage of S307. Referring to the above, it is determined whether or not a certain condition for determining the end of the initial heating stage is satisfied. When the determination condition is not satisfied (S308-No), the inside of the heating chamber 34 is continuously dispersed and heated, and the temperature distribution in the heating chamber 34 is detected again after a predetermined time.

  When the determination condition is satisfied (S308-Yes), the process proceeds to a step of determining whether or not each area where the temperature detecting unit detects the temperature is an area where food is placed. In this step, for example, the temperature increase rate per unit time of each area where the temperature is detected is referred to, and if it is equal to or greater than a predetermined value, it is determined that food is placed in that area. In addition, referring to the initial temperature for each region where the temperature is detected, if the initial temperature is a low temperature (for example, if the temperature is lower than the temperature assumed for frozen food, etc.), the region is loaded with food. It may be determined that the area is placed. Thus, in the step of S309, among all the regions in the heating chamber 34, the region where the food is placed and the other region where the food is not placed are discriminated, and the radio wave control mode 411a is set. Store it (S309).

  If the origin detection error is stored in the determination in S304, the process proceeds to S351, the error is notified to the user, and the process returns to S302.

  If at least one of the plurality of stirrers is not an origin detection error, heating may be continued.

When the initial heating stage ends, the microwave oven 31 proceeds to the heating feedback stage. The operation in the heating feedback stage will be described with reference to FIG. The temperature distribution detecting means of the microwave oven 31 detects the entire temperature distribution in the heating chamber 34 after the heating initial stage is completed (S107). And the area | region of the minimum temperature in the area | region where it determines with the foodstuff being mounted in the heating chamber 34 is extracted, ie, the minimum temperature location is extracted among foodstuff locations (S108). Further, the highest temperature region in the region where it is determined that the food is placed in the heating chamber 34 is extracted, that is, the highest temperature portion is extracted from the food portion (S109).

  When the temperature difference between the temperature at the highest temperature location and the temperature at the lowest temperature location is taken and it is determined that the temperature difference is less than the predetermined temperature (S110-No), it is assumed that the mode is a distributed heating mode in which uniform heating is performed ( S111).

  The radio wave control mode 411a performs an end determination after executing the step of S111 (S112). For example, when the maximum temperature of the food temperature distribution exceeds a preset temperature, the heat treatment end determination condition for determining that the heat treatment is to be terminated, or when the average temperature of the location determined as food exceeds the set temperature It is determined whether or not a heat treatment end determination condition for determining to end the heat treatment is satisfied.

  If the heat treatment end determination condition is satisfied (S112—Yes), the process proceeds to S302 shown in FIG. 14, the origin detection process is performed in the origin detection mode 411b, and a heating start instruction is awaited in the origin detection state.

  When the heat treatment end determination condition is not satisfied (S112—No), the process proceeds to the step of S107, and the steps after S107 are repeated again.

  When it is determined that the temperature difference between the temperature at the highest temperature location and the temperature at the lowest temperature location is equal to or higher than the predetermined temperature (S110-Yes), it is set when returning from the local heating mode to the distributed heating mode in the processing described later. If it is determined that the local heating mode transition grace time has elapsed (S113-Yes), the antenna stop time is initialized in order to measure the time during which the antenna can be heated centrally in the local heating mode ( S114). And it transfers to local heating mode (S115). If it is determined that the local heating mode transition postponement time is not completed (S113-No), the local heating mode transition postponement time is measured (S116) without shifting to the local heating mode, and distributed. It shall return to the process (S111) which continues heating mode.

  The operation in the local heating mode will be described with reference to FIGS. 16 and 17. It is determined whether or not the lowest temperature location extracted in step S108 is one of the regions B2, B3, C2, and C3 in FIG. 13 (S117). When the lowest temperature location is one of B2, B3, C2, and C3 (S117-Yes), the radio wave control mode 411a is in the direction in which the rotating antennas 38 and 39 heat the center in the heating three chamber 34. That is, the operation control is executed so that the rotating antennas 38 and 39 are stopped at the stop position shown in FIG. 4 (S118).

  If the lowest temperature location is not any of B2, B3, C2, and C3 (S117-No), then it is determined whether the lowest temperature location is any of B1 and C1 among the food locations. (S119).

  When the lowest temperature portion is one of the areas B1 and C1 (S119-Yes), the radio wave control mode 411a is in the direction in which the rotating antennas 38 and 39 heat the left direction in the heating chamber 34, that is, in the figure. Operation control is executed so that the rotating antennas 38 and 39 are stopped at the stop position shown in FIG.

  If the lowest temperature location is neither B1 nor C1 (S119-No), it is then determined whether the lowest temperature location of the food location is B4 or C4 (S121).

  When the lowest temperature portion is one of B4 and C4 (S121-Yes), the radio wave control mode 411a is in the direction in which the rotating antennas 38 and 39 heat the right direction in the heating chamber 34, that is, in the figure. Operation control is executed so that the rotating antennas 38 and 39 are stopped at the stop position shown in FIG. 6 (S122).

  If the lowest temperature location is not in any of B4 and C4 (S121-No), it is then determined whether the lowest temperature location of the food location is A2 or A3 (see FIG. 17). S123).

  When the lowest temperature location is any one of A2 and A3 (S123-Yes), the radio wave control mode 411a is in the direction in which the rotating antennas 38 and 39 heat the front direction in the heating chamber 34, that is, Operation control is executed so that the rotating antennas 38 and 39 are stopped at the stop position shown in FIG. 7 (S124).

  When the lowest temperature location is not in any of the areas A2 and A3 (S123-No), it is subsequently determined whether the lowest temperature location is D2 or D3 among the food locations (S125). .

  When the lowest temperature location is one of D2 and D3 (S125-Yes), the radio wave control mode 411a is in the direction in which the rotating antennas 38 and 39 heat the rearward direction in the heating chamber 34, that is, FIG. Operation control is executed so that the rotating antennas 38 and 39 are stopped at the stop position shown in FIG. 8 (S126).

  If the lowest temperature location is neither D2 nor D3 (S125-No), it is then determined whether the lowest temperature location is A1 among the food locations (S127).

  When the lowest temperature portion is the area of A1 (S127-Yes), the radio wave control mode 411a stops the rotating antennas 38 and 39 in the direction in which the rotating antennas 38 and 39 heat the left front direction in the heating chamber 34. Thus, the operation control is executed (S128).

  When the lowest temperature location is not the area of A1 (S127-No), it is determined whether the lowest temperature location is A4 among the food locations (S129).

  When the lowest temperature portion is the A4 region (S129-Yes), the radio wave control mode 411a stops the rotating antennas 38 and 39 in the direction in which the rotating antennas 38 and 39 heat the right front direction in the heating chamber 34. Thus, the operation control is executed (S130).

  When the lowest temperature location is not the area of A4 (S129-No), it is determined whether the lowest temperature location is D1 among the food locations (S131).

  When the lowest temperature location is the region of D1 (S131-Yes), the radio wave control mode 411a stops the rotating antennas 38 and 39 so that the rotating antennas 38 and 39 heat the left rear direction in the heating chamber 34. The operation control is executed so as to be performed (S132).

When the lowest temperature location is not A4 (S131-No), the lowest temperature location is D4.
Therefore, the radio wave control mode 411a performs operation control so that the rotating antennas 38 and 39 are stopped in a direction in which the rotating antennas 38 and 39 heat the right rear direction in the heating chamber 34 (S133).

  In the radio wave control mode 411a, after executing any step of S118, S120, S122, S124, S126, S128, S130, S132, and S133, the process proceeds to S134 shown in FIG. It is detected (S134). And the area | region of the highest temperature in the area | region where it determines with the foodstuff being mounted in the heating chamber 34 is extracted, ie, the highest temperature location is extracted among foodstuff locations (S135). Here, the extraction of the lowest temperature portion of the food portion is not performed. Here, the lowest temperature location is the lowest temperature location at the time of transition to the local heating mode, that is, the location that is heated intensively by local heating. Specifically, the lowest temperature location shown in S109 of FIG. The location determined by the extraction process is shown.

  Next, the radio wave control mode 411a takes the temperature difference between the temperature at the highest temperature location and the temperature at the lowest temperature location, and when it is determined that the temperature difference is less than a predetermined temperature (S136-No), the local heating mode After performing the step (S137) of setting a predetermined time as the transition grace time, the process proceeds to the step (S111) of shifting to the dispersion heating mode.

  If it is determined that the temperature difference between the highest temperature location and the lowest temperature location is equal to or higher than the predetermined temperature (S136-Yes), the antenna stop time is counted (S138), and the antenna stop time is the upper limit for stopping the antenna. Determine if the time has been reached. When the antenna stop time reaches the upper limit time, the local heating mode is discontinued, and the process proceeds to step S137. If the antenna stop time is less than the upper limit time, an end determination is subsequently performed (S140). For example, when the maximum temperature of the food temperature distribution exceeds a preset temperature, the heat treatment end determination condition for determining that the heat treatment is to be terminated, or when the average temperature of the location determined as food exceeds the set temperature It is determined whether or not a heat treatment end determination condition for determining to end the heat treatment is satisfied.

  When the heat treatment end determination condition is satisfied (S140-Yes), the process proceeds to S302 shown in FIG. 14, the origin detection process is performed in the origin detection mode 411b, and a heating start instruction is waited in the origin detection state.

  When the heat treatment end determination condition is not satisfied (S140-No), the process proceeds to the step of S117, and the steps after S117 are repeated again.

  As described above, the microwave oven 31 according to the first embodiment can intensively heat a specific portion in the heating chamber 34 by two rotating antennas, and is heated with an object to be heated. Since the temperature distribution of a certain food can be detected, and a spot can be applied to the lowest temperature portion of the food to be heated locally, the food can be heat-treated without unevenness.

  In addition, the local heating and the dispersion heating can be switched according to the temperature distribution of the food, that is, the microwave can be concentrated at a necessary place, so that the food can be efficiently heated in a short time.

  And, the process of detecting the origin that is the reference for driving the rotating antenna is performed after the power is turned on and after the heating is completed. Heating can be started.

Note that the operation control in the heating feedback stage described in FIGS. 15 to 17 is not limited to the order in which the lowest temperature portion of the food is searched. As a result, if the entire food is searched, it is executed in another order. You may do it.

  As described above, according to the present invention, a specific portion to be heated can be centrally heated by controlling a portion having a strong radiation directivity of a rotating antenna disposed in a heating chamber in a predetermined direction. It can also be applied to uses such as dielectric heating, thawing, ceramics heating, drying, sintering, or biochemical reaction.

Sectional drawing which shows the front cross section of the microwave heating device of Embodiment 1 of this invention Sectional drawing in A-A 'of FIG. 1 of the microwave heating apparatus Sectional drawing in B-B 'of Drawing 1 of the microwave heating device Explanatory drawing explaining the direction of the rotating antenna when locally heating the vicinity of the center in the heating chamber of the microwave heating apparatus Explanatory drawing explaining direction of a rotating antenna when the left side in the heating chamber of the microwave heating apparatus is locally heated Explanatory drawing explaining direction of a rotating antenna when heating the right side in the heating chamber of the microwave heating apparatus locally Explanatory drawing explaining direction of a rotating antenna when the front of the heating chamber of the microwave heating apparatus is locally heated Explanatory drawing explaining direction of a rotation antenna when heating the back of the heating chamber of the microwave heating device locally Sectional drawing in D-D 'of FIG. 1 for demonstrating the origin detection mechanism of the rotating antenna of the same microwave heating device Plan sectional view of the microwave heating device with three rotating antennas Sectional view of temperature distribution detection means of the microwave heating apparatus Explanatory drawing explaining the infrared temperature detection spot in the C-C 'cross section of FIG. 1 of the microwave heating device Configuration diagram of control means of the microwave heating device Flowchart explaining origin detection and control operation at initial stage of heating of microwave heating apparatus Flow chart for explaining the control operation in the heating feedback stage of the microwave heating apparatus Flowchart explaining control operation in local heating control mode of same microwave heating apparatus Flowchart explaining control operation in local heating control mode of same microwave heating apparatus

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 (6)

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 light, driving means for rotating the rotating antennas, origin detecting means for detecting that each rotating antenna is at a predetermined origin position, 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 is configured to connect at least one of the plurality of rotating antennas to a microwave radiation directivity. A radio wave control mode for controlling a strong portion in a direction determined based on the detection result of the temperature distribution detection means, and until the origin detection means detects the origin Has an origin detection mode for rotating the rotating antenna, the microwave heating apparatus in driving the respective rotating antennas by the origin detection mode where the structure stopping the microwave generator. The control means includes an antenna angle storage unit that stores an angle that is a rotational position 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, Claims: Control is performed so that a portion having a strong radiation directivity of the rotating antenna is directed to a low temperature portion of the temperature of each detection region detected by the distribution detection means, and the antenna is stopped until the temperature difference between the low temperature portion and the high temperature portion becomes small. 2. The microwave heating apparatus according to 1. The control means performs control to rotate the antenna again when a predetermined time or more elapses when the portion having a strong radiation directivity of the rotating antenna is directed to the low temperature portion of the temperature of each detection region detected by the temperature distribution detecting means. The microwave heating device according to claim 1 or 2. When the control means controls the rotation antenna to rotate again by directing 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 detection means, until a predetermined time elapses, The microwave heating device according to any one of claims 2 to 3, wherein control for directing a portion having a strong radiation directivity of the rotating antenna to a low temperature portion is suppressed again. It further has a display means for displaying menu setting contents, cooking time, etc., and displays the rotation status of the rotating antenna so as to notify the user of the location being heated in the heating chamber. Item 5. The microwave heating apparatus according to any one of Items 1 to 4. The user further has a setting means for selecting a heating menu, etc., and when the user inputs a portion to be heated particularly, the portion having a strong radiation directivity of the rotating antenna is directed to the designated portion to perform heating control. The microwave heating apparatus according to claim 5.

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