Patent Publication Number: US-8525086-B2

Title: Microwave heating appliance

Description:
TECHNICAL FIELD 
     The present invention relates to a microwave heating appliance for dielectrically heating a heated subject. 
     BACKGROUND ART 
     The microwave oven as a typical microwave heating appliance can heat directly the foods as a typical heated subject. Therefore, its convenience of needing no cooking pan or pot makes the microwave oven the appliance indispensable to life. Up to now, the microwave oven having a food loading space, width and depth dimensions of which is about 300 to 400 mm respectively and a height dimension of which is about 200 mm, of the heating chamber through which a microwave propagates is widespread commonly. 
     In recent years, the products having a heating chamber whose food loading space has a flat bottom surface and whose lateral width is widened by setting the width dimension to 400 mm or more relatively larger than the depth dimension such that a plurality of food plates can be heated to enhance its convenience are put to practical use. 
     By the way, it has been known that a wavelength of the microwave used in the microwave oven is about 120 mm, strong and weak electric field distributions (referred to as “field strength distributions” hereinafter) are caused in the heating chamber, and thus unevenness in heating is caused by a synergistic effect of such unevenness and influences of the shape of the heated subject and its physical property. In particular, in the above heating chamber having the large width dimension, uniformity of the heating must be increased rather than the prior art to heat simultaneously the foods put in plural dishes. 
     In the prior art, in this type microwave heating appliance, one radiation antenna is provided and is rotated and driven in operation, but it is difficult to heat locally a center area of the heating chamber. Therefore, as the measure of enhancing uniformity in heating, the microwave heating appliance equipped with a plurality of radiation antennas or a plurality of high-frequency stirring unit has been proposed (see Patent Literature 1). 
     However, the microwave heating appliance does not always heat a large amount of foods, although such heating appliance has a wide heating chamber. For example, when a mug of milk is warmed, it is effective to heat concentratedly the milk only, not heat uniformly the overall heating chamber. 
     Also, when a plurality of foods are heated at the same time, only the low-temperature food should be heated concentratedly in a situation that a difference resides in temperatures of the foods, for example, the frozen food and the room-temperature food should be heated simultaneously. In addition, like the variety box lunch, or the like, the foods not to be heated (pickles, salad, dessert, etc.) are contained in as one vessel. Therefore, often only the foods to be heated (boiled rice, side dishes, etc.) should be heated concentratedly. 
     In such case, a function of not heating uniformly the overall heating chamber but heating concentratedly the local area is needed. For this reason, the microwave heating appliance capable of heating concentratedly the heated subject by switching a plurality of antennas and controlling the stop position, and the like has been proposed (see Patent Literature 2).
     Patent Literature 1: JP-A-2004-259646   Patent Literature 2: Japanese Patent No. 3617224   

     DISCLOSURE OF THE INVENTION 
     Problems that the Invention is to Solve 
     By reference to Patent Literatures 1, 2, first it seems that, if a plurality of radiation antennas are provided to the right and left sides in the heating chamber having the wide lateral width, uniform heating of the overall heating chamber would be realized. Also, as to the concentrated heating to the local area, the heat can be concentrated to a top end side of the unipole antenna to some extent if the radiation antenna is stopped, for example. However, it is the question to what extent the heat can be concentrated. It is difficult for the actual configuration to realize a locally concentrated heating in response to the purpose while achieving normally a uniform heating in the overall heating chamber. 
     The present invention has been made to solve the above problems, and it is an object of the present invention to provide a microwave heating appliance capable of achieving a locally concentrated heating in answer to the purpose while achieving a uniform heating in the overall heating chamber in a normal mode. 
     Means for Solving the Problems 
     A microwave heating appliance of the present invention, includes a microwave generating unit; a waveguide which transmits a microwave from the microwave generating unit; a heating chamber which houses a heated subject that is heated by the microwave; a rotating antenna which radiates the microwave from the waveguide to the heating chamber; a driving unit which rotates and drives the rotating antenna; a temperature distribution detecting unit which detects a temperature distribution in the heating chamber; and a controlling unit which controls a direction of the rotating antenna by controlling the driving unit based on a detected result of the temperature distribution detecting unit, wherein the controlling unit controls a sharp part of radiation directivity of a plurality of the rotating antennas in a direction decided based on the detected result of the temperature distribution detecting unit to execute a concentrated heating, and wherein the driving unit has a position detecting unit which detects a position of the rotating antenna. 
     According to this configuration, the adequate localized heating can be realized by directing the sharp part of the radiation directivity of the rotating antenna toward the area in which the heating is needed in the heating chamber, while referring to the detected result of the temperature distribution detecting unit, and also the uniform heating in the heating chamber can be realized by rotating the rotating antenna ordinarily, or the like. Also, the position of the rotating antenna can be detected by the position detecting unit. 
     Also, a microwave heating appliance of the present invention includes a microwave generating unit; a waveguide which transmits a microwave from the microwave generating unit; a heating chamber which houses a heated subject that is heated by the microwave; a plurality of rotating antennas which radiates the microwave from the waveguide to the heating chamber; a driving unit which rotates and drives the rotating antennas; a temperature distribution detecting unit which detects a temperature distribution in the heating chamber; and a controlling unit which controls directions of the rotating antennas by controlling the driving unit based on a detected result of the temperature distribution detecting unit, wherein the controlling unit controls a sharp part of radiation directivity of at least one of the plurality of rotating antennas in a direction decided based on the detected result of the temperature distribution detecting unit to execute a concentrated heating. 
     According to this configuration, the adequate localized heating can be realized by directing the sharp part of the radiation directivity of the rotating antenna to the area in which the heating is needed in the heating chamber, while referring to the detected result of the temperature distribution detecting unit, and also the uniform heating in the heating chamber can be realized by rotating the rotating antenna ordinarily, or the like. 
     Also, in the microwave heating appliance of the present invention, the controlling unit includes an antenna controlling portion having a localized heating mode controlling portion which controls the sharp part of the radiation directivity of the rotating antenna in the direction decided based on the detected result of the temperature distribution detecting unit to execute the concentrated heating, and a distributed heating mode controlling portion for heating uniformly an interior of the heating chamber. 
     According to this configuration, the interior of the heating chamber can be not only heated concentratedly but also heated uniformly. 
     Also, in the microwave heating appliance of the present invention, the antenna controlling portion controls the rotating antenna by the distributed heating mode controlling portion in an initial stage of heating start, and controls the rotating antenna by the localized heating mode controlling portion after the initial stage is ended. 
     According to this configuration, the heated subject can be heated concentratedly after the interior of the heating chamber is heated uniformly. 
     Also, the microwave heating appliance of the present invention, the antenna controlling portion controls the rotating antenna by the localized heating mode controlling portion in an initial stage of heating start, and controls the rotating antenna by the distributed heating mode controlling portion after the initial stage is ended. 
     According to this configuration, the interior of the heating chamber can be heated uniformly after the heated subject is heated concentratedly. 
     Also, in the microwave heating appliance of the present invention, the controlling unit includes a food deciding portion which decides whether or not a heated subject loaded in the heating chamber is a food, and controls the rotating antenna based on a temperature of a food area of the food decided by the food deciding portion. 
     According to this configuration, when the heated subject is the food, the rotating antenna can be controlled based on the temperature of the food area. 
     Also, in the microwave heating appliance of the present invention, the controlling unit includes an antenna angle storing portion which stores an angle of the rotating antenna when the sharp part of the radiation directivity of the rotating antenna is directed to a particular area in the heating chamber, and the controlling unit directs the sharp part of the radiation directivity of the rotating antenna toward a low temperature portion of detected areas detected by the temperature distribution detecting unit. 
     According to this configuration, the low temperature portion can be heated locally with good precision, by storing data collected previously by the experiment in the antenna angle storing portion. 
     Also, in the microwave heating appliance of the present invention, the distributed heating mode controlling portion executes the distributed heating by changing a stop position of the rotating antenna every moment, rotating continuously the rotating antenna, or changing the stop position of the rotating antenna at random. 
     According to this configuration, the distributed heating can be executed by changing the stop position of the rotating antenna every moment, rotating continuously the rotating antenna, or changing the stop position of the rotating antenna at random. 
     Also, in the microwave heating appliance of the present invention, the localized heating mode controlling portion has a reciprocating angle storing portion for storing a reciprocating angle, and the localized heating mode controlling portion makes a reciprocating swinging motion of the rotating antenna around an angle decided by referring to the antenna angle storing portion based on the detected result detected by the temperature distribution detecting unit, by an angle stored in the reciprocating angle storing portion. 
     According to this configuration, such a situation can be prevented that, because the rotating antenna continues to stop during the radiation of the microwave, the microwave concentrates excessively to a part of the rotating antennas to cause the excessive heating. Even when the rotating antennas are moved by about ±5 degree around the target angle, the localized heating effect to the heated subject is not influenced but an effect enough to prevent the excessive temperature rise of antenna components can be attained. 
     Also, in the microwave heating appliance of the present invention, the localized heating mode controlling portion has a stop upper limit time storing portion for storing an upper limit time in which the rotating antenna is stopped at a predetermined angle, and a stop time counting portion which counts a time in which the rotating antennas stop, and when a time counted by the stop time counting portion reaches a time stored in the stop upper limit time storing portion, the rotating antenna is moved to a position that is shifted by a predetermined angle. 
     According to this configuration, such a situation can be prevented that, because the rotating antenna continues to stop during the radiation of the microwave, the microwave concentrates excessively to a part of the rotating antennas to cause the excessive heating. In other words, the condition under which no heated subject is put in the heating chamber gives the most severe condition that is applied to decide experimentally the upper limit time, for the antenna components may be melt down when the microwave is locally concentrated with no load for 30 second to 1 minute. Therefore, a time shorter than the above time, e.g., about 30 second, is set as an upper limit time, and the rotating antenna is rotated just by an angle of 5 degree, for example, when the heating time exceeds this upper limit time. 
     Also, in the microwave heating appliance of the present invention, the temperature distribution detecting unit includes a plurality of infrared detecting elements, and a driving unit which moves the plurality of infrared detecting elements in a direction that intersects with a direction along which the plurality of infrared detecting elements are aligned. 
     According to this configuration, a plurality of infrared detecting elements can be moved in the direction that intersects with the direction along which the infrared detecting elements are aligned. 
     Also, in the microwave heating appliance of the present invention, the driving unit includes a position detecting unit which detects a position of the rotating antenna. 
     According to this configuration, the position of the rotating antenna can be detected by the position detecting unit. 
     Also, in the microwave heating appliance of the present invention, the position detecting unit detects an origin of the rotating antenna in an origin detecting mode. 
     According to this configuration, the origin of the rotating antenna can be detected in the origin detecting mode by the position detecting unit. 
     Also, in the microwave heating appliance of the present invention, the origin of the rotating antenna is checked before a heating process is executed or after a heating process is executed in the origin detecting mode. 
     According to this configuration, the origin of the rotating antenna can be confirmed in the origin detecting mode before a heating process is executed or after a heating process is executed. 
     Also, in the microwave heating appliance of the present invention, the controlling unit stops an operation of a magnetron while the rotating antenna is driven in the origin detecting mode. 
     According to this configuration, the operation of a magnetron is stopped while the rotating antenna is driven in the origin detecting mode. Thus, generation of the unintended heating state can be prevented. 
     Also, in the microwave heating appliance of the present invention, the controlling unit contains a menu indicating that, when the origin is not found in the origin detecting mode, an error is decided and the execution of the heating process is inhibited, and a menu indicating that the heating process is executed in a state that the rotating antenna is stopped. 
     According to this configuration, according to the cooking menu, e.g., when the menu in which it does not matter if deviation of the temperature distribution in the heating chamber occurs, the heating process is executed while the operation of the rotating antenna is stopped. Therefore, the microwave heating appliance can provide the minimum function to the user. 
     Also, in the microwave heating appliance of the present invention, rotating centers of the plurality of rotating antennas are arranged at a substantially equal distance from a center of the interior of the heating chamber. 
     According to this configuration, the rotating centers of the rotating antennas are arranged at a substantially equal distance from the center of the heating chamber respectively. Therefore, this configuration enables the sharp radiation directivity part of the rotating antennas, when directed to the center area and its neighborhood, to heat the center area and its neighborhood of the heating chamber, which normally one antenna configuration is hard to heat. 
     Also, in the microwave heating appliance of the present invention, a a stepping motor is used as the driving unit, and a time difference is provided to timings for inputting a pulse into each stepping motor corresponding to each antenna, in every stepping motor. 
     According to this configuration, a time difference is provided to timings for inputting a pulse into each stepping motor corresponding to each antenna, in every stepping motor. Therefore, provision of the circuit capable of handling a large current can be neglected, and a size increase of the circuit can be prevented. 
     Advantages of the Invention 
     According to the present invention, the microwave heating appliance capable of achieving a locally concentrated heating in response to the purpose while achieving the uniform heating of the overall heating chamber in a normal mode can be provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front sectional configurative view of a microwave heating appliance of Embodiment 1 of the present invention. 
         FIG. 2  is a side sectional configurative view of the microwave heating appliance (a sectional view taken along an A-A′ line in  FIG. 1 ). 
         FIG. 3  is a plan sectional configurative view of the microwave heating appliance (a sectional view taken along a B-B′ line in  FIG. 1 ). 
         FIG. 4  is a view explaining the direction of a rotating antenna when the center area and its neighborhood in a heating chamber is localizedly heated. 
         FIG. 5  is a view explaining the direction of a rotating antenna when the left side in a heating chamber is localizedly heated. 
         FIG. 6  is a view explaining the direction of a rotating antenna when the right side in a heating chamber is localizedly heated. 
         FIG. 7  is a view explaining the direction of a rotating antenna when the front side in a heating chamber is localizedly heated. 
         FIG. 8  is a view explaining the direction of a rotating antenna when the rear side in a heating chamber is localizedly heated. 
         FIG. 9  is a view explaining an origin detecting mechanism of the rotating antenna (a sectional view taken along a D-D′ line in  FIG. 1 ). 
         FIG. 10  is a planar sectional view of the microwave heating appliance equipped with three rotating antennas. 
         FIG. 11  is a schematic sectional configurative view of a temperature distribution detecting unit. 
         FIG. 12  is a view explaining infrared temperature detecting spots in a section along a C-C′ line in  FIG. 1 . 
         FIG. 13  is a schematic configurative view of a controlling unit  411 . 
         FIG. 14  is a flowchart explaining a controlling operation in the initial stage of the heating. 
         FIG. 15  is a flowchart explaining a controlling operation in the heating feedback stage. 
         FIG. 16  is a flowchart explaining a controlling operation in the heating feedback stage of Embodiment 2 of the present invention. 
         FIG. 17  is a view showing a variation of the rotating antenna. 
         FIG. 18  is a view showing another variation of the rotating antenna. 
         FIG. 19  is a view showing another variation of the rotating antenna. 
     
    
    
     DESCRIPTION OF REFERENCE NUMERALS AND SIGNS 
     
         
         
           
               10  temperature sensor (temperature detecting unit) 
               31  microwave oven (microwave heating appliance) 
               32  magnetron (microwave generating unit) 
               33  waveguide 
               34  heating chamber 
               35  loading table 
               37  antenna space 
               38 ,  39  rotating antenna 
               40 ,  41  motor (driving unit) 
               411  controlling unit 
           
         
       
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Embodiments according to the present invention will be explained in detail with reference to the drawings hereinafter. 
     Embodiment 1 
       FIG. 1  to  FIG. 3  are configurative views of a microwave oven  31  as a typical microwave heating appliance of according to the present invention.  FIG. 1  is a sectional view of the microwave oven when viewed from a front side,  FIG. 2  is a sectional view of the same taken along an A-A′ line in  FIG. 1 ,  FIG. 3  is a sectional view of the same taken along a B-B′ line in  FIG. 1 ,  FIG. 4  is a sectional view of the same taken along a C-C′ line in  FIG. 1 . 
     As shown in  FIG. 1 , a microwave oven  31  is equipped with a waveguide  33  for transmitting a microwave radiated from a magnetron  32  as the typical microwave generating unit, a heating chamber  34  connected to an upper portion of the waveguide  33  and having a shape whose dimension in the width direction (about 410 mm) is larger than a dimension in the depth direction (about 315 mm), a loading table  35  fixed in the heating chamber  34  to load a food (not shown) as the typical heated subject thereon and formed of a low loss dielectric material such as ceramic, glass, or the like such that the microwave easily passes through there, an antenna space  37  formed in the heating chamber  34  under the loading table  35 , two rotating antennas  38 ,  39  fitted in the waveguide  33  to the antenna space  37  in symmetrical positions with respect to the width direction of the heating chamber  34  to radiate the microwave from the waveguide  33  to an interior of the heating chamber  34 , motors  40 ,  41  as typical driving unit for rotating/driving the rotating antennas  38 ,  39 , a controlling unit  411  for controlling the direction of the rotating antennas  38 ,  39  by controlling the motors  40 ,  41 , photo interrupters  36  constituting an origin detecting mechanism for detecting an origin of the rotating antennas  38 ,  39  respectively, and an infrared sensor  10  as a temperature distribution detecting unit for detecting a temperature distribution in the heating chamber  34 . 
     Also, as shown in  FIG. 2 , the microwave oven  31  has a door  64 . Also, a setting unit  63  is provided to the lower portion of the door  64 . The user can choose various cooking menus in accordance with the food or the cooking process by using the setting unit  63 . The controlling unit  411  controls the magnetron  32  and the motors  40 ,  41  based on this chosen result. 
     The rotating antennas  38 ,  39  have the radiation directivity respectively. The microwave oven  31  of Embodiment 1 is constructed such that the sharp radiation directivity part of at least one of the rotating antennas  38 ,  39  is controlled in a predetermined direction to heat concentratedly the particular food. It will be explained later how this microwave oven  31  should be controlled concretely. 
     Also, the rotating antennas  38 ,  39  have coupling portions  45 ,  46  provided to the boundary between the waveguide  33  and the heating chamber bottom surface  42 , and radiating portions  47 ,  48  connected electrically integrally to upper ends of the coupling portions  45 ,  46  by the caulking, the welding, or the like. The coupling portions  45 ,  46  are formed of an almost cylindrical conductive material of about 18 mm diameter to pass through almost circular coupling holes  43 ,  44  of about 30 mm diameter. The radiating portions  47 ,  48  are formed of the conductive material that is wider generally in the horizontal direction rather than the vertical direction. 
     Also, the rotating antennas  38 ,  39  are fitted on shafts  49 ,  50  of the motors  40 ,  41  such that centers of the coupling holes  43 ,  44  coincide with centers of the rotating/driving operations. The radiating portions  47 ,  48  have an uneven profile in the rotating direction to have their radiation directivity respectively. 
     The rotating centers of the rotating antennas  38 ,  39  are arranged at an almost equal distance from a center of the heating chamber  34  respectively. This configuration enables the sharp radiation directivity part of the rotating antennas  38 ,  39 , when directed to the center area and its neighborhood, to heat the center area and its neighborhood of the heating chamber  34 , in which normally one antenna configuration is hard to heat. 
     As shown in  FIG. 3 , the waveguide  33  is constructed like a T-shape and has a bilaterally symmetrical shape when viewed from the top. Therefore, respective distances from the magnetron  32  to the coupling portions  45 ,  46  are equal and the coupling portions  45 ,  46  are fitted to symmetrical positions in the width direction of the heating chamber  34 . As a result, the microwave radiated from the magnetron  32  is distributed substantially uniformly in the heating chamber  34  via the waveguide  33  and the rotating antennas  38 ,  39 . 
     The radiating portions  47 ,  48  have the same shape such that radiating portion upper surfaces  51 ,  52  are shaped into an almost quadrangle whose four corners are rounded respectively. Radiating portion bent portions  53 ,  54  that are bent to the heating chamber bottom surface  42  side are provided to two opposing sides respectively to restrict the radiation of the microwave toward the outsides of two sides. Respective distances from the heating chamber bottom surface  42  to the radiating portion upper surfaces  51 ,  52  are set to about 10 mm, and the radiating portion bent portions  53 ,  54  are pulled down to the positions that are set lower than the radiating portion upper surfaces  51 ,  52  by about 5 mm respectively. 
     Also, remaining two sides have different lengths from the coupling portions  45 ,  46  to their end portions in the horizontal direction, and constitute end portions  55 ,  56  whose length from the center of the coupling portion is about 75 mm respectively and end portions  57 ,  58  whose length from the center of the coupling portion is about 55 mm respectively. Also, both dimensions of the end portions in the width direction are set to 80 mm or more. According to this configuration, the rotating antennas  38 ,  39  can enhance the radiation directivity in the direction from the coupling portions  45 ,  46  to the end portions  57 ,  58 . 
     In this configuration, when the ordinary food is heated uniformly, the location of such food is not particularly considered like the known microwave oven, and also the rotating antennas  38 ,  39  may be rotated uniformly like the known art. In contrast, in the case of the concentrated heating, when the center area and its neighborhood in the heating chamber  34  is to be heated, the controlling unit  411  controls the rotating antennas  38 ,  39  such that, as shown in  FIG. 4 , their end portions  57 ,  58  are directed in a predetermined direction that aims at an almost center of the heating chamber  34  in the width direction and an almost center in the depth direction. 
     When the end portions  57 ,  58  of the rotating antennas  38 ,  39  are directed to the almost center of the heating chamber  34  in the width direction and the almost center in the depth direction, the radiation directivity toward the end portions  57 ,  58  becomes sharp. Therefore, the microwave is radiated particularly from the direction of the end portions  57 ,  58  and thus the food positioned in that direction can be heated concentratedly. 
     Also, when the left-side area in the heating chamber  34  is to be heated, the controlling unit  411  controls the rotating antennas  38 ,  39  such that, as shown in  FIG. 5 , their end portions  57 ,  58  are directed leftward (the left side when the heating chamber  34  is viewed from the door  64  side). 
     When both end portions  57 ,  58  of the rotating antennas  38 ,  39  are directed leftward when the heating chamber  34  is viewed from the door  64  side, the radiation directivity of respective antennas toward the end portions  57 ,  58  becomes sharp. Therefore, the microwave is radiated particularly from the direction of the end portions  57 ,  58  and thus the food positioned in that direction can be heated concentratedly. 
     Similarly, when the right-side area in the heating chamber  34  is to be heated, the controlling unit  411  controls the rotating antennas  38 ,  39  such that, as shown in  FIG. 6 , their end portions  57 ,  58  are directed rightward (the right side when the heating chamber  34  is viewed from the door  64  side). 
     When both end portions  57 ,  58  of the rotating antennas  38 ,  39  are directed rightward when the heating chamber  34  is viewed from the door  64  side, the radiation directivity of respective antennas toward the end portions  57 ,  58  becomes sharp. Therefore, the microwave is radiated particularly from the direction of the end portions  57 ,  58  and thus the food positioned in that direction can be heated concentratedly. 
     Also, when the front center area and its neighborhood in the heating chamber  34  is to be heated, the controlling unit  411  controls the rotating antennas  38 ,  39  such that, as shown in  FIG. 7 , their end portions  57 ,  58  are directed to aim at an almost center of the heating chamber  34  in the width direction and an almost front area in the depth direction (the front center area and its neighborhood in the heating chamber  34 ). 
     As shown in  FIG. 7 , when the end portions  57 ,  58  of the rotating antennas  38 ,  39  are directed to the front center area and its neighborhood in the heating chamber  34 , the radiation directivity of respective antennas toward the end portions  57 ,  58  becomes sharp. Therefore, the microwave is radiated particularly from the direction of the end portions  57 ,  58  and thus the food positioned in that direction can be heated concentratedly. 
     Also, when the rear center area and its neighborhood in the heating chamber  34  is to be heated, the controlling unit  411  controls the rotating antennas  38 ,  39  such that, as shown in  FIG. 8 , their end portions  57 ,  58  are directed to aim at an almost center of the heating chamber  34  in the width direction and an almost rear area in the depth direction (the rear center area and its neighborhood in the heating chamber  34 ). 
     As shown in  FIG. 8 , when the end portions  57 ,  58  of the rotating antennas  38 ,  39  are directed to the rear center area and its neighborhood in the heating chamber  34 , the radiation directivity of respective antennas toward the end portions  57 ,  58  becomes sharp. Therefore, the microwave is radiated particularly from the direction of the end portions  57 ,  58  and thus the food positioned in that direction can be heated concentratedly. 
     As described above, the microwave oven  31  of Embodiment 1 controls the direction of the rotating antennas in response to the area that is to be localizedly heated. In order to direct the rotating antennas  38 ,  39  in a predetermined direction, various unit may be considered, for example, a stepping motor is employed as the motors  40 ,  41 , a power feed time of a certain motor is controlled by detecting a reference position, and the like. 
     In the microwave oven  31  of Embodiment 1, a stepping motor is employed as the motors  40 ,  41 , and a position detecting unit for detecting the antenna position is provided to shafts of the motors  40 ,  41  respectively. This antenna position detecting unit can be constructed by a rotary encoder, a potentiometer, or the like, for example, which is well known to detect a rotating position of the rotation shaft. In the present embodiment, the antenna position detecting unit is constructed by an origin detecting mechanism described later. That is, as shown in  FIG. 9 , the origin detecting mechanism is composed of a circular plate  36   a  having the shaft as a center shaft and the photo interrupter  36 . A rectangular slit  36   b  is provided to the circular plate  36   a.    
     The circular plate  36   a  is fitted commonly to the shafts  49 ,  50  of the motors to rotate the rotating antennas  38 ,  39  respectively. The circular plate  36   a  rotates to block a light path of the photo interrupter  36  consisting of a light emitting element and a light receiving element. 
     According to this configuration, the light path is not blocked when the slit  36   b  passes through the light path of the photo interrupter  36 , this mechanism can detect a point of time when the slit passes. For this reason, when a position of the slit  36   b  is set to the origins of the rotating antennas  38 ,  39 , the photo interrupter  36  fitted to respective motors can detect the origins of the rotating antennas. 
     Also, the controlling unit  411  has an antenna angle storing portion that stores previously angles (stop positions) of the rotating antennas  38 ,  39  on the basis of the origin that the origin detecting mechanism can detect when the sharp radiation directivity part of the rotating antennas  38 ,  39  are concentrated to the localized heating area. When the localized heating is executed by controlling the operations of the rotating antennas  38 ,  39 , information in this antenna angle storing portion is referred to. 
     The case where two rotating antennas are provided is explained up to now. However, the number of rotating antennas is not limited to this, a plurality of rotating antennas in excess of two may be employed. For example, as shown in  FIG. 10 , the microwave heating appliance may be equipped with three rotating antennas. In a state shown in  FIG. 10 , end portions of respective rotating antennas are directed to the center area and its neighborhood in the heating chamber, and the food positioned around the center area can be concentratedly heated. 
     Next, a temperature detecting unit that the microwave oven  31  of Embodiment 1 has with reference to  FIG. 11  hereunder. This temperature detecting unit has a plurality of infrared detecting elements  13  aligned on a base plate  19 , a case  18  for housing the overall base plate  19 , and a stepping motor  11  for moving the case  18  in the direction that intersects orthogonally with the direction along which the infrared detecting elements  13  are aligned. 
     A metal can  15  for sealing the infrared detecting elements  13 , and an electronic circuit  20  for processing an operation of the infrared detecting element are provided to the base plate  19 . Also, a lens  14  for passing through the infrared ray is provided to the metal can  15 . Also, an infrared ray passing hole  16  for passing through an infrared ray and a hole  17  for passing through lead wires from the electronic circuit  20  are provided to the case  18 . 
     According to this configuration, when the stepping motor  11  is rotated, the case  18  can be moved in the direction perpendicular to the direction along which the infrared detecting elements  13  are aligned. 
       FIG. 12  is a view explaining infrared temperature detecting spots in a section along a C-C′ line in  FIG. 1 . As shown in  FIG. 12 , when the stepping motor  11  of the temperature detecting unit does a reciprocating motion, the microwave oven  31  of Embodiment 1 can detect the temperature distribution in substantially all areas in the heating chamber  34 . 
     Concretely, for example, first the temperature detecting elements  13  (e.g., infrared sensors) aligned in the temperature detecting unit detect simultaneously the temperature distributions in spots A 1  to A 4  in  FIG. 12 . Then, when the stepping motor  11  is further rotated to move the case  18 , the temperature detecting elements  13  detect the temperature distributions in spots B 1  to B 4 . Then, when the stepping motor  11  is further rotated to move the case  18 , the temperature detecting elements  13  detect the temperature distributions in spots C 1  to C 4 . Similarly, the temperature distributions in spots D 1  to D 4  are detected. 
     Also, when the stepping motor  11  is rotated inversely subsequent to the above operation, the temperature distributions are detected sequentially from the spots D 1  to D 4  side in order of C 1  to C 4 , B 1  to B 4 , and A 1  to A 4 . The temperature detecting unit can detect the overall temperature distributions in the heating chamber  34  by repeating the above operations. 
     Next, a schematic configuration of the controlling unit  411  will be explained with reference to  FIG. 13  hereunder. The controlling unit  411  is constructed to have an antenna controlling portion  101  for controlling operations of the rotating antennas  38 ,  39 , a food deciding portion  102  for deciding whether or not the heated subject loaded in the heating chamber  34  is the food, an end-of-initial-stage-of-heating deciding portion  103  for deciding an end of the initial stage of the heating process, and an end-of-heating deciding portion  104  for deciding an end of the overall heating process. 
     The food deciding portion  102  has an initial temperature distribution storing portion  108  for storing an initial temperature distribution of the heated subject, and a temperature rise rate calculating portion  109  for calculating a temperature rise rate of the heated subject per unit time. When the calculated temperature rise rate is in excess of a predetermined value, the food deciding portion  102  decides that the heated subject is the food. In other words, this food deciding portion  102  decides whether the area from which the temperature is detected corresponds either the loading table on which the heated subject is put or the food as the heated subject. This food deciding portion  102  makes a decision based on a difference in the temperature characteristic because the loading table passes through the microwave to hardly raise its temperature whereas the food tends to absorb the microwave to raise its temperature. 
     The end-of-initial-stage-of-heating deciding portion  103  decides whether or not the initial stage of the heating process is ended, for example, based on the criterion under which it is decided that the initial stage of the heating is ended when a predetermined time elapsed from the start of heating, the criterion under which it is decided that the initial stage of the heating is ended when a maximum temperature of the heated subject reached a predetermined temperature of more, or the criterion under which it is decided that when a maximum value of a temperature change of the heated subject since the start of heating exceeds a predetermined value. 
     The end-of-heating deciding portion  104  decides whether or not the heating process is ended, for example, based on the criterion under which it is decided that the heating process is ended when the maximum temperature of the heated subject in the temperature distribution exceeds a previously set temperature, the criterion under which it is decided that the heating process is ended when an average temperature at the area where the food exists exceeds a set temperature, or the criterion under which it is decided that the heating process is ended when a time required until the maximum temperature of the heated subject reaches a predetermined temperature is measured in advance, the heating process is executed for an additional heating time that constitutes a predetermined rate (e.g., 50%) of the total required time, and then the additional heating time expires. 
     The antenna controlling portion  101  is constructed to have a distributed heating mode controlling portion  105  for controlling the operations of the rotating antennas  38 ,  39  to heat uniformly the interior of the heating chamber, a localized heating (spot heating) mode controlling portion  106  for controlling the operations of the rotating antennas  38 ,  39  to heat a low-temperature portion of the heated subject, and a low temperature extracting portion  107  for detecting the low-temperature portion of the heated subject loaded in the heating chamber. 
     The distributed heating mode controlling portion  105  is constructed to implement the distributed heating, for example, by changing stop positions of the rotating antenna  38 ,  39  that can localizedly heat the subject by stopping in predetermined positions during the microwave oscillation, by rotating continuously the rotating antennas  38 ,  39 , or by changing the stop positions of the rotating antennas  38 ,  39  at random. 
     The localized heating mode controlling portion  106  gets information of the lowest temperature area from the low temperature extracting portion  107 , and controls the directions of the rotating antennas  38 ,  39  such that the food is localizedly heated. For example, when the lowest temperature area is either of spots B 2 , B 3 , C 2 , C 3  in  FIG. 12 , the rotating antennas  38 ,  39  are directed to heat the center area, i.e., the rotating antennas  38 ,  39  are stopped in the stop positions shown in  FIG. 4 . 
     Also, when the lowest temperature area is either of spots B 1 , C 1  in  FIG. 12 , the rotating antennas  38 ,  39  are directed to heat the left direction, i.e., the rotating antennas  38 ,  39  are stopped in the stop positions shown in  FIG. 5 . Also, when the lowest temperature area is either of spots B 4 , C 4  in  FIG. 12 , the rotating antennas  38 ,  39  are directed to heat the right direction, i.e., the rotating antennas  38 ,  39  are stopped in the stop positions shown in  FIG. 6 . 
     Also, when the lowest temperature area is either of spots A 2 , A 3  in  FIG. 12 , the rotating antennas  38 ,  39  are directed to heat the front area, i.e., the rotating antennas  38 ,  39  are stopped in the stop positions shown in  FIG. 7 . Also, when the lowest temperature area is either of spots D 2 , D 3  in  FIG. 12 , the rotating antennas  38 ,  39  are directed to heat the rear area, i.e., the rotating antennas  38 ,  39  are stopped in the stop positions shown in  FIG. 8 . 
     As described above, the controlling unit  411  controls the stop positions of the rotating antennas  38 ,  39  in response to the lowest temperature area that the temperature detecting unit detected. In this case, when the radiation of the microwave into the heating chamber  34  is still continued while the rotating antennas are stopped in the predetermined position, there is a risk that a temperature of the rotating antennas themselves excessively rises and the rotating antennas are melted. 
     In view of this respect, the localized heating mode controlling portion  106  of the controlling unit  411  causes the rotating antennas to make a reciprocating swinging motion around a target angle (stop position) by about a predetermined angle (e.g., ±5 degree) in the above localized heating mode. As a result, a degradation of the rotating antennas can be prevented without any influence on the localized heating effect. Also, such a situation can be prevented that, because the rotating antennas continue to stop during the radiation of the microwave, the microwave concentrates excessively to a part of the rotating antennas to cause the excessive heating. This reciprocating swinging motion may be made immediately after the start of the localized heating, but also may be started after a predetermined time elapsed (e.g., after 30 second to 1 minute). 
     In order to execute this reciprocating swinging motion, the controlling unit  411  has a stop upper limit time storing portion for storing previously an upper limit time in which the stop of the rotating antennas  38 ,  39  is allowed, a stop time counting portion for counting a time in which the rotating antennas stop, and a reciprocating angle storing portion for storing an angle by which the reciprocating swinging motion of the rotating antennas  38 ,  39  is made. 
     Also, the rotating antennas may be rotated by a predetermined angle (e.g., 5 degree) after a predetermined time elapsed (e.g., after 30 seconds to 1 minute) from the start of the localized heating. 
     Also, the controlling unit  411  stores predetermined stop positions (angles) of the rotating antennas  38 ,  39  as the origins. Then, the controlling unit  411  executes an origin detecting mode that checks the origins of the rotating antennas  38 ,  39  either before the execution of the heating process or after the execution of the heating process, for example. 
     During the origin detecting mode, the angles of the rotating antennas  38 ,  39  cannot be specified. Thus, when the microwave is still oscillated as it is, the unintentional heating mode is caused and sometimes acts as the cause of failure. Therefore, the controlling unit  411  executes a control to stop the operation of the magnetron while the rotating antennas are driven during the origin detecting mode. 
     Also, the controlling unit  411  executes the origin detecting mode after the end of the heating process, and standbys in the non-heating mode in a state that the origins were detected. Thus, such a situation can be prevented that a standby time for the origin detection is generated before the heating process is started. 
     Also, the controlling unit  411  contains a menu indicating that, when the origin was not found in the origin detecting mode, an error is decided and the execution of the subsequent heating process is inhibited, and a menu indicating that the heating process is executed in a state that the rotating antennas  38 ,  39  are stopped. According to this configuration, the heating process is executed while the operation of the rotating antennas  38 ,  39  is still stopped according to the cooking menu, for example, when the menu in which it does not matter if deviation of the temperature distribution in the heating chamber  34  occurs (it does not matter if unevenness occurs as long as simply the heating process can be executed, or the like) is chosen, and as a result the minimum function can be provided to the user. 
     In this case, when the motor  40 ,  41  for driving the rotating antennas  38 ,  39  get broken, often the origins cannot be detected. Therefore, it is not safe to operate the rotating antennas  38 ,  39  as they are, and thus the operation of the rotating antennas  38 ,  39  should be stopped. 
     In contrast, in the case of a menu indicating that the user cannot realize the heating process to give a desired result if the temperature distribution in the heating chamber  34  is deviated, the execution itself of the heating process is inhibited. 
     Also, the controlling unit  411  may heat uniformly the whole heating chamber  34  in a distributed heating mode in the initial stage of the heating start, and then may shift the above heating mode to the localized heating mode after an occurrence of difference in the temperature distribution in the heating chamber  34  begins. Since no difference in the temperature distribution occurs in the heating chamber  34  in the initial stage of the heating start, a temperature of the overall heating chamber  34  can be increased effectively in the distributed heating mode. 
     Also, first the controlling unit  411  may heat locally the center area and the neighborhood in the heating chamber  34  in the initial stage of the heating start. Normally, when the heating process is started from a condition that there is no difference in the temperature distribution in the heating chamber, the center area and the neighborhood in the heating chamber is mostly hard to increase a temperature. Therefore, when first the center area and the neighborhood in the heating chamber  34  are locally heated and then the whole heating chamber  34  is heated uniformly by the distributed heating, the overall heating chamber can be heated uniformly effectively. 
     Also, the motor  40 ,  41  for driving the rotating antennas  38 ,  39  may be constructed by the stepping motor, for example. At this time, the controlling unit  411  may execute a control such that a time difference is provided to timings for inputting a pulse into respective stepping motors fitted to the rotating antennas  38 ,  39 , every stepping motor so as not to overlap the timings with each other. When the pulses are input simultaneously, a current required at that timing is increased and thus a circuit capable of handling a large current must be provided to the microwave oven  31 . In this case, a size increase of the circuit can be prevented by providing a time difference upon inputting the pulses. 
     Next, an operation of the microwave oven  31  of Embodiment 1 will be explained hereunder. First, a controlling operation in the initial stage of the heating will be explained with reference to  FIG. 14  hereunder. 
     At first, when the heating operation is started, the magnetron  32  generates the microwave and the microwave is transmitted to the heating chamber  34  via the waveguide (S 101 ). At this time, the temperature detecting unit detects the temperature distribution in the heating chamber  34  at an initial point of time in the heating, and the controlling unit  411  stores the detected result of the temperature distribution (S 102 ). 
     Then, the controlling unit  411  causes the rotating antennas  38 ,  39  to rotate at a constant speed, for example, to realize the distributed heating (S 103 ). After a predetermined time elapsed, the temperature detecting unit detects again the temperature distribution (S 104 ). 
     Then, the end-of-initial-stage-of-heating deciding portion  103  of the controlling unit  411  decides whether or not the criterion to decide that the initial stage of the heating is ended is satisfied, by referring to the temperature distribution in the heating chamber in the initial stage of the heating detected in the step S 102  and the temperature distribution in the heating chamber after a predetermined time elapsed detected in the step S 104 . If the criterion is not satisfied (S 105 —No), the interior of the heating chamber  34  is heated distributedly. After a predetermined time elapsed, the temperature detecting unit detects again the temperature distribution in the heating chamber  34 . 
     If the criterion is satisfied (S 105 —Yes), the controlling unit  411  decides whether or not the areas in which the temperature is detected by the temperature detecting unit correspond to the area for putting the food (S 106 ). In this step, for example, the controlling unit  411  refers to a temperature rise rate per unit time on the area in which the temperature is detected, and then decides that the food is put on the area when the temperature rise rate is in excess of a predetermined value. Also, the controlling unit  411  may refer to the initial temperature of the area in which the temperature is detected, and then may decide that the food is put on the area when the initial temperature is minus (e.g., the frozen food, or the like is supposed). In this manner, in step S 106 , the controlling unit  411  discriminates the area for putting the food and other areas for not putting the food in all areas in the heating chamber  34 , and stores the result therein (S 106 ). 
     When the initial stage of the heating is ended, the operation of the microwave oven  31  shifts subsequently to the heating feedback stage. Then, a controlling operation in the heating feedback stage will be explained with reference to  FIG. 15  hereunder. The temperature distribution detecting unit of the microwave oven  31  detects the whole temperature distribution in the heating chamber  34  after the heating initial stage is ended (S 107 ). The temperature detecting unit extract a lowest temperature spot in the area on which the food is put in the heating chamber  34 , i.e., extract the lowest temperature spot of the food area (S 108 ). 
     The temperature detecting unit decides whether or not the lowest temperature spot is either of spots B 2 , B 3 , C 2 , C 3  (S 109 ). If the lowest temperature spot is either of spots B 2 , B 3 , C 2 , C 3  (S 109 —Yes), the controlling unit  411  executes the operation control such that the rotating antennas  38 ,  39  are directed to heat the center area in the heating chamber  34 , i.e., the rotating antennas  38 ,  39  are stopped in the stop positions shown in  FIG. 4  (S 117 ). 
     If the lowest temperature spot is none of spots B 2 , B 3 , C 2 , C 3  (S 109 —No), subsequently the temperature detecting unit decides whether or not the lowest temperature spot of the food area is either of spots B 1 , C 1  (S 110 ). 
     If the lowest temperature spot is either of spots B 1 , C 1  (S 110 —Yes), the controlling unit  411  executes the operation control such that the rotating antennas  38 ,  39  are directed to heat the left direction in the heating chamber  34 , i.e., the rotating antennas  38 ,  39  are stopped in the stop positions shown in  FIG. 5  (S 118 ). 
     If the lowest temperature spot is none of spots B 1 , C 1  (S 110 —No), subsequently the temperature detecting unit decides whether or not the lowest temperature spot of the food area is either of spots B 4 , C 4  (S 111 ). 
     If the lowest temperature spot is either of spots B 4 , C 4  (S 111 —Yes), the controlling unit  411  executes the operation control such that the rotating antennas  38 ,  39  are directed to heat the right direction in the heating chamber  34 , i.e., the rotating antennas  38 ,  39  are stopped in the stop positions shown in  FIG. 6  (S 119 ). 
     If the lowest temperature spot is none of spots B 4 , C 4  (S 111 —No), subsequently the temperature detecting unit decides whether or not the lowest temperature spot of the food area is either of spots A 2 , A 3  (S 112 ). 
     If the lowest temperature spot is either of spots A 2 , A 3  (S 112 —Yes), the controlling unit  411  executes the operation control such that the rotating antennas  38 ,  39  are directed to heat the front area in the heating chamber  34 , i.e., the rotating antennas  38 ,  39  are stopped in the stop positions shown in  FIG. 7  (S 120 ). 
     If the lowest temperature spot is none of spots A 2 , A 3  (S 112 —No), subsequently the temperature detecting unit decides whether or not the lowest temperature spot of the food area is either of spots D 2 , D 3  (S 113 ). 
     If the lowest temperature spot is either of spots D 2 , D 3  (S 113 —Yes), the controlling unit  411  executes the operation control such that the rotating antennas  38 ,  39  are directed to heat the rear area in the heating chamber  34 , i.e., the rotating antennas  38 ,  39  are stopped in the stop positions shown in  FIG. 8  (S 121 ). 
     If the lowest temperature spot is none of spots D 2 , D 3  (S 113 —No), subsequently the controlling unit  411  goes to the distributed heating mode in which the antennas  38 ,  39  are rotated at a constant speed to heat uniformly the interior of the heating chamber  34  (S 114 ). 
     Then, the controlling unit  411  makes the end decision after it executes any one of S 114 , S 117  to S 121  (S 115 ). For example, the controlling unit  411  decides whether or not either the heating process ending criterion under which it is decided that the heating process is ended when the maximum temperature in the temperature distribution of the food exceeds a previously set temperature or the heating process ending criterion under which it is decided that the heating process is ended when an average temperature of the area that is decided as the food exceeds a set temperature is satisfied. 
     If it is decided that the heating process ending criterion is satisfied (S 115 -Yes), the heating process is ended (S 116 ). In contrast, if it is not decided that the heating process ending criterion is satisfied (S 115 —No), the process goes back to step S 107  and step S 107  et seq. are repeated again. 
     As described above, the microwave oven  31  of Embodiment 1 can heat concentratedly the particular area in the heating chamber  34  by two rotating antennas, and can heat locally the lowest temperature spot of the food by detecting the temperature distribution of the food as the heated subject during the heating process. Therefore, the microwave oven  31  of Embodiment 1 can execute the heating process of the food without unevenness. 
     Also, the microwave oven  31  of Embodiment 1 can switch the localized heating and the distributed heating in response to the temperature distribution of the food, i.e., can concentrate the microwave to the necessary area. Therefore, the microwave oven  31  of Embodiment 1 can heat the food effectively in a short time. 
     Here, in the operation control in the heating feedback stage explained in  FIG. 15 , the sequence along which the lowest temperature spot of the food is searched is not limited to this illustrated example. Other sequences may be employed if the whole food area can be searched consequently. 
     Embodiment 2 
       FIG. 16  is a flowchart explaining a controlling operation in the heating feedback stage of the microwave oven of Embodiment 2 of the present invention. In following explanation, the same reference numerals are affixed to the same constituent elements as those explained above and their description will be omitted herein. 
     The microwave oven  31  of Embodiment 2 enters the heating feedback stage shown in  FIG. 16  after the heating initial stage is ended. A difference between the heating feedback control of Embodiment 1 shown in  FIG. 15  and the heating feedback control of Embodiment 2 shown in  FIG. 16  resides in that the heating feedback control of Embodiment 2 classifies respective areas (A 1  to A 4 , B 1  to B 4 , C 1  to C 4 , D 1  to D 4 ) in the heating chamber  34  into a center area A (B 2 , B 3 , C 2 , C 3 ), a left area B (B 1 , C 1 ), a right area C (B 4 , C 4 ), a front area D (A 2 , A 3 ), and a rear area E (D 2 , D 3 ), and then executes the heating feedback based on the average temperature of the food area in the classified areas. 
     The operation control in the heating feedback stage of Embodiment 2 will be explained with reference to  FIG. 16  hereunder. The temperature detecting unit of the microwave oven  31  detects the temperature distribution of the whole heating chamber  31  after the heating initial stage is ended (S 201 ). Then, the temperature detecting unit calculates an average temperature of respective food areas of the center area A=(B 2 , B 3 , C 2 , C 3 ), the left area B=(B 1 , C 1 ), the right area C=(B 4 , C 4 ), the front area D=(A 2 , A 3 ), and the rear area E=(D 2 , D 3 ) every area (S 202 ). 
     In rotating, the temperature detecting unit detects the area whose average temperature is lowest among the classified areas (A-F), and the controlling unit  411  controls the operations of the rotating antennas  38 ,  39  in response to the result. First, the temperature detecting unit decides whether or not the lowest temperature area (the area in which the average temperature is lowest) among the classified areas (A to F) is the center area A (S 203 ). If the lowest temperature area is the center area A (S 203 —Yes), the controlling unit  411  executes the operation control such that the rotating antennas  38 ,  39  are directed to heat the center area in the heating chamber  34 , i.e., the rotating antennas  38 ,  39  are stopped in the stop positions shown in  FIG. 4  (S 210 ) 
     If the lowest temperature area is not the center area A (S 203 —No), subsequently the temperature detecting unit decides whether or not the lowest temperature area among the classified areas (A to F) is the left area B (S 204 ). Then, if the lowest temperature area is the left area B (S 204 —Yes), the controlling unit  411  executes the operation control such that the rotating antennas  38 ,  39  are directed to heat the left side in the heating chamber  34 , i.e., the rotating antennas  38 ,  39  are stopped in the stop positions shown in  FIG. 5  (S 211 ). 
     If the lowest temperature area is not the left area B (S 204 —No), subsequently the temperature detecting unit decides whether or not the lowest temperature area among the classified areas (A to F) is the right area C (S 205 ). If the lowest temperature area is the right area C (S 205 —Yes), the controlling unit  411  executes the operation control such that the rotating antennas  38 ,  39  are directed to heat the right side in the heating chamber  34 , i.e., the rotating antennas  38 ,  39  are stopped in the stop positions shown in  FIG. 6  (S 212 ). 
     If the lowest temperature area is not the right area C (S 205 —No), subsequently the temperature detecting unit decides whether or not the lowest temperature area among the classified areas (A to F) is the front area D (S 206 ). If the lowest temperature area is the front area D (S 206 —Yes), the controlling unit  411  executes the operation control such that the rotating antennas  38 ,  39  are directed to heat the front side in the heating chamber  34 , i.e., the rotating antennas  38 ,  39  are stopped in the stop positions shown in  FIG. 7  (S 213 ). 
     If the lowest temperature area is not the front area D (S 206 —No), subsequently the temperature detecting unit decides whether or not the lowest temperature area among the classified areas (A to F) is the rear area E (S 207 ). If the lowest temperature area is the rear area E (S 207 —Yes), the controlling unit  411  executes the operation control such that the rotating antennas  38 ,  39  are directed to heat the rear side in the heating chamber  34 , i.e., the rotating antennas  38 ,  39  are stopped in the stop positions shown in  FIG. 8  (S 214 ). 
     If the lowest temperature area is not the rear area E (S 207 —No), subsequently the controlling unit  411  goes to the distributed heating mode in which the antennas  38 ,  39  are rotated at a constant speed to heat uniformly the interior of the heating chamber  34  (S 208 ). 
     Then, the controlling unit  411  makes the end decision after it executes any one of S 208 , S 210  to S 214  (S 209 ). Like Embodiment 1, for example, the controlling unit  411  decides whether or not either the heating process ending criterion under which it is decided that the heating process is ended when the maximum temperature in the temperature distribution of the food exceeds a previously set temperature or the heating process ending criterion under which it is decided that the heating process is ended when an average temperature of the area that is decided as the food exceeds a set temperature is satisfied. 
     If it is decided that the heating process ending criterion is satisfied (S 209 -Yes), the heating process is ended (S 116 ). In contrast, if it is not decided that the heating process ending criterion is satisfied (S 209 —No), the process goes back to step S 201  and step S 201  et seq. are repeated again. 
     In this manner, the microwave oven  31  of Embodiment 2 decides the localized heating area based on the average temperature of the food areas of the predetermined classified area (A-E). Therefore, even when the temperature is extremely low only at a part of the food, the concentrated heating can be applied the area of which the heating is required as the whole food. 
     Embodiment 3 
     As the microwave oven of Embodiment 3, a variation of the rotating antenna will be explained hereunder. In following explanation, the same reference numerals are affixed to the same constituent elements as those explained above and their description will be omitted herein. For example, as shown in  FIG. 17 , a circular plate-shaped antenna to a part of which an opening portion is provided may be used as the rotating antenna. 
     Concretely, in  FIG. 17 , rotating antennas  83 ,  84  have circular arc-like opening portions  87 ,  88  on radiating portions  85 ,  86 . A length L of the opening portions  87 ,  88  in the width direction is set to a ¼ wave, or more of the microwave being radiated in the heating chamber. Therefore, the rotating antennas  83 ,  84  have the radiation directivity at the opening portion when stopped, and thus can heat locally the particular area in the heating chamber  34 . 
     Also, as another variation of the rotating antenna, for example, as shown in  FIG. 18 , there are rectangular rotating antennas  90 ,  91 . In the rotating antennas  90 ,  91 , three sides of the rectangular shape have bent portions  94 ,  95  that bent toward the bottom surface side of the heating chamber, and remaining one side portions  92 ,  93  are not bent. One side portions  92 ,  93  that are not bent have the sharp directivity, and thus the rotating antennas  90 ,  91  can heat locally the particular area in the heating chamber  34 . 
     Also, as still another variation of the rotating antenna, for example, as shown in  FIG. 19 , there are rectangular rotating antennas  201 ,  202 . In the rotating antennas  201 ,  202 , four sides of the rectangular shape have bent portions  203 ,  204  that bent toward the bottom surface side of the heating chamber, and opening portions  208 ,  209  are provided on radiating portions  206 ,  207 . Thus, the rotating antennas  201 ,  202  have the sharp directivity, and can heat locally the particular area in the heating chamber  34 . 
     Also, respective rotating antennas are spaced apart at a mutual distance of 5 mm or more. Accordingly, such a situation can be prevented that respective rotating antennas interfere with each other and thus a part of the rotating antennas is broken because of excessive heating. 
     In this case, the embodiments given as above can be carried out variously in combination. 
     The present invention is explained in detail with reference to the particular embodiments. However, it is apparent for those skilled in the art that various variations and modifications can be applied without departing a spirit and a scope of the present invention. 
     The present invention is explained in detail with reference to the particular embodiments. However, it is apparent for those skilled in the art that various variations and modifications can be applied without departing a spirit and a scope of the present invention. 
     This application is based upon Japanese Patent Application (Patent Application No. 2006-169268) filed on Jun. 19, 2006; the contents of which are incorporated herein by reference. 
     INDUSTRIAL APPLICABILITY 
     As described above, the present invention can heat concentratedly the particular heated subject by controlling the sharp part of the radiation directivity of the rotating antennas arranged in the heating chamber in the predetermined direction. Therefore, the present invention can be applied to various applications such as heating, unfreezing, ceramic art heating, drying, sintering of various dielectric materials such as the food, etc., the biochemical reaction, and the like.