JP2002093569A - Microwave heating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable to complete heating of two or more objects at the same temperature, in a heating method using microwaves. SOLUTION: The heating method is constituted of a first step detecting a temperature distribution of an installation face on which objects are laid, and judging an existence position of the above objects, the second step making the microwave deflect to an area where the temperature is low, in order to make the above temperature distribution equalized, when the maximum of the temperature distribution information on the above installation face detected in a predetermined time cycle, is under the heating completion temperature, and a third step terminating the heating when the maximum of the above temperature information is more than the heating completion temperature. Since the object having a low temperature can be strongly heated by deflecting the microwave to the low temperature side of the object, by detecting the existence and the temperature state of the object from the temperature distribution data, by judging the object whether it is a plurality or not, each object can be finished to the almost same temperature without uneven heating also to two or more heated objects.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave heating method capable of deflecting microwaves based on the temperature of an object to be heated and completing heating at a predetermined temperature without uneven heating.

[0002]

2. Description of the Related Art A conventional high frequency heating apparatus using a microwave is a component technology mainly for uniformly heating an object to be heated, a turntable mechanism for rotating the object to be heated, and a microwave in a heating chamber. A stirrer mechanism for stirring or a rotating antenna mechanism for changing the radiation direction of the microwave is employed.

[0003] On the other hand, in recent years, with the change of lifestyle, there has been a tendency to actively use ready-made prepared foods and frozen preserved foods for rationalization of cooking, and to make individual meals for families to eat individually. I'm advancing. It has been desired to simultaneously heat a plurality of foods in response to such a change in lifestyle. However, in a conventional heating method that focuses on uniform heating, approximately the same proportion of heating energy is supplied to a plurality of foods. Therefore, if the amount of ingredients is different, the one with a large amount will have a low temperature rise and insufficient heating, and even if the same ingredients are the same amount and the initial ingredient temperature is different, low temperature ingredients will be underheated,
It was difficult to finish several ingredients at the same time.

[0004] In order to solve this problem, a method of individually detecting the temperature of a plurality of foods using an infrared sensor is different from a method of positively utilizing the strength of a microwave distribution generated in a heating chamber for storing an object to be heated. There has been provided an apparatus for simultaneously heating and finishing a food material having a temperature or a plurality of different food materials.

[0005] These high-frequency heating devices include a turntable on which an object to be heated is placed, a weight sensor for detecting the weight of the object to be heated, and an infrared sensor for detecting the surface temperature of the object to be heated. Then, when simultaneously heating objects to be heated at different temperatures to achieve the same temperature, first, the turntable is rotated with respect to an infrared sensor having a specific visual field position to detect the temperature distribution over the entire area of the turntable. Then, the placement position of the high-temperature or low-temperature object to be heated is detected, the low-temperature-side object to be heated is rotated to a position where the microwave distribution is strong, the turntable is stopped at that position, and the low-temperature-side object to be heated is actively activated. For example, when the object to be heated on the high temperature side moves to a position where the microwave distribution is strong, the microwave output is reduced to prevent overheating.

[0006]

However, in a configuration using a conventional turntable, the microwave heating control performed on each of the objects to be heated depends on the rotation speed of the turntable. In the case of a heated product, the heating time is short, so there is no time for fully utilizing the effect of the simultaneous finishing. Further, with respect to simultaneous heating of a plurality of objects to be heated having greatly different amounts, there is a problem that an object to be heated having a small amount is excessively heated.

In addition, the method of lowering the microwave output in order to prevent excessive heating increases the total heating time, and cannot take advantage of the microwave heating that the object to be heated can be heated in a short time. In addition, since the output is not completely stopped from the above viewpoint, there is a problem that the object to be heated which has become high temperature is further heated.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems. A plurality of objects to be heated are simultaneously finished by deflecting a microwave in an existing region of the object to be heated and strongly heating the object to be heated. It is intended to provide a microwave heating method.

[0009]

In order to solve the above-mentioned problems, a microwave heating method according to the present invention detects a temperature distribution on a mounting surface on which an object to be heated is placed, and detects a position of the object to be heated. When the maximum value of the temperature distribution information of the mounting surface detected at a predetermined cycle time is less than the heating end temperature, a microwave is applied to a region with a low temperature to uniform the temperature distribution. The method comprises a second step of deflecting and a third step of terminating the heating when the maximum value of the temperature information is equal to or higher than the heating end temperature. This detects the presence or absence of the object to be heated and the temperature state from the temperature distribution data, determines whether there is a plurality of objects to be heated in the presence of the object to be heated, and deflects the microwave to the lower temperature side of the object to be heated. By doing so, the object to be heated having a low temperature can be strongly heated, so that even for a plurality of objects to be heated, the objects to be heated can be finished at substantially the same temperature without uneven heating.

[0010]

According to the first aspect of the present invention, a first step of detecting a temperature distribution on a mounting surface on which an object to be heated is mounted to determine a position of the object to be heated, A second step of deflecting the microwave to a low-temperature region in order to equalize the temperature distribution when the maximum value of the temperature distribution information of the mounting surface detected in the cycle time is less than the heating end temperature, and the temperature information And a third step of terminating the heating when the maximum value is equal to or higher than the heating end temperature. Thereby, the presence / absence of the object to be heated and the temperature state are detected by the temperature detecting means, and the microwaves can be concentrated / dispersed on the side of the object having a low temperature, so that the heating can be completed to a predetermined temperature without uneven heating. is there.

[0011] The invention described in claim 2 is particularly advantageous in claim 1.
The method of deflecting the microwave described in the above, by increasing the impedance value of the opening portion arranged so as to divide the flow of the high-frequency current flowing through the wall surface of the heating chamber containing the object to be heated, It is to suppress.

Thus, the microwave can be quickly deflected with a simple configuration.

[0013] The invention described in claim 3 is particularly advantageous in claim 1.
Is changed in conjunction with the microwave output.

Thus, as the microwave output becomes higher, the period is shortened, and the degree of temperature rise of the object to be heated is detected in detail, so that the presence / absence of temperature unevenness is determined at an early stage. And control the variance,
The temperature of a plurality of objects to be heated can be made uniform.

According to a fourth aspect of the present invention, the position of the object to be heated is determined based on an absolute value of the detected temperature or a temperature rise value within a predetermined time. It is.

Thus, regardless of the difference in the initial temperature of the object to be heated, the number of the objects to be heated can be determined, and heating can be performed according to the number of the objects to be heated.

According to a fifth aspect of the present invention, in the determination of the number of the objects to be heated according to the first aspect, the microwave is dispersed until the determination of the number of the objects to be heated is completed.

Thus, all the objects to be heated placed on the mounting surface can be dielectrically heated, so that the number of the objects can be reliably determined.

According to a sixth aspect of the present invention, there is provided a method of dispersing a microwave according to the fifth aspect of the present invention, in which a flow of a high-frequency current flowing through a wall surface of a heating chamber for storing an object to be heated is divided. The flow of the high-frequency current is varied by temporally changing the impedance value of the provided aperture.

Thus, microwaves can be dispersed and radiated to the entire heating chamber in which the object to be heated is housed, and all the objects to be heated can be heated to raise the temperature of the object regardless of the initial temperature state. it can.

The invention according to claim 7 is a method according to claim 1, wherein, in the first step of the microwave heating method according to claim 1,
If the number of objects to be heated is determined to be plural and the temperatures of the objects to be heated are different, the microwave is deflected toward the object to be heated having the lowest temperature.

Thus, a plurality of objects to be heated having different initial temperatures can be quickly heated to a predetermined temperature without uneven heating.

[0023] The invention described in claim 8 is particularly directed to the first step of the microwave heating method described in claim 1.
If the number of objects to be heated is not determined to be plural within the upper limit temperature of the first stage and the temperature distribution of the object to be heated is non-uniform, the microwave is deflected to a low temperature region.

Thus, the heating of one object to be heated can be completed without uneven heating.

According to a ninth aspect of the present invention, in the first stage of the microwave heating method of the first aspect, if it is determined that there is no object to be heated, the microwave heating is stopped. And stop heating.

As a result, waste of power consumption when there is no object to be heated can be suppressed, and deterioration of the magnetron can be prevented.

[0027] The invention according to claim 10 is particularly characterized in that it is determined that there is no object to be heated according to claim 9 and after the microwave heating is stopped, it is determined that there is no object to be heated. It is.

Thus, the user can recognize that the heating is stopped because there is no object to be heated, and the usability can be improved.

[0029]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(Embodiment) FIG. 1 is an external structural view of a microwave heating apparatus according to the microwave heating method of the present invention, and FIG.
Is a side view of the configuration (a door portion is indicated by a wavy line).

1 and 2, reference numeral 10 denotes a heating chamber for storing an object to be heated, and the wall surface of the heating chamber 10 is made of metal. Reference numeral 11 denotes a mounting table on which an object to be heated is mounted. The magnetron (microwave generating means) 12 generates a microwave by the electric power supplied from the magnetron driving power supply 13. The microwave generated from the magnetron 12 is transmitted to the power supply port 15 by the waveguide 14 and is radiated from the power supply port 15 to the heating chamber 10. Wall surface 16 forming heating chamber 10
Are provided with openings 17 and 18. Each opening 1
7 and 18 are impedance variable means 19 and 20 for changing the impedance of the apertures 17 and 18 respectively.
Is arranged. These impedance variable means 19,
The configuration of 20 will be described as representative of the impedance variable means 19 arranged in the opening 17.

Reference numeral 21 denotes a groove made of metal having the opening 17 as one end, and reference numeral 22 denotes a dielectric plate provided in the groove 21. The dielectric plate 22 is preferably made of a low dielectric loss material (for example, glass, ceramic, or resin) having a relative permittivity of 5 or more, and has projections at both ends thereof. And is supported by rotation. The dielectric plate 22 is rotationally driven by a motor 23 which is a dielectric plate rotation driving unit. Angle detecting means 24 for detecting the rotation angle and rotation speed of the dielectric plate 22
Are arranged.

The groove depth, the groove height and the position of the dielectric plate of each groove of the impedance variable means 19 are determined when the dielectric plate 22 is horizontal to the terminal wall 21a of the groove 21 (at this time, The rotation angle of the dielectric plate 22 is 0 °),
The impedance generated in the opening 17 is determined to be an extremely small value (ideally, zero). When the dielectric plate 22 is perpendicular to the terminal wall surface 21a of the groove 21 (at this time, the rotation angle of the dielectric plate 22 is 90 °), the impedance generated in the opening 17 is extremely small. It is set to a large value (ideally infinite). The rotation angle of the dielectric plate 22 of the impedance varying means 19 is 90
In the case of °, the impedance of the opening 17 corresponding thereto becomes infinite, and the high-frequency current flowing through the wall surface 16 around the opening 17 is cut off, and the microwave is kept away from the vicinity of the opening 17. Therefore, the opening 17 of the impedance varying means 19 in which the rotation angle of the dielectric plate 22 is set to 90 °.
To deflect the microwaves away from the side. Regarding the heating of the object to be heated, the side where the microwaves are gathered is strongly heated by deflecting the microwaves.

In this embodiment, the number of rotations per minute during the rotation control of the dielectric plate 22 is represented by a suffix *. For example, an infrared sensor 25 is provided at the center of the back wall of the heating chamber 10 and the impedance varying means 1 varies the impedance of the apertures 17 and 18 provided on the left and right sides.
When the rotation of each of 9 and 20 is controlled at 15 rotations per minute and 3 rotations per minute, it is expressed as 15 * / IR / 3 *.

Reference numeral 25 denotes an infrared sensor (temperature detecting means) for detecting the temperature of the object to be heated. In this embodiment, an infrared sensor having four 1 × 4 elements was used. In addition, the infrared sensor 25 is configured to swing, and its field of view is adjusted so that the temperature of the entire mounting table 11 can be detected. 1 and 2, the inside of the dashed line indicates the field of view. 26 is an operation unit provided on the front of the apparatus main body, and 27 is a display means for displaying the temperature of the object to be heated. In the operation section 26, an input setting section 28 for inputting the end temperature of the object to be heated, an input setting section 29 for inputting the heating time, a "start" key 30 for inputting the start of heating, and a "cancel" for clearing input conditions or interrupting the heating. Key 31 and an automatic cooking selection key 32 are provided. Automatic cooking selection key 32
Includes automatic cooking items such as “thaw” and “warm”.

Reference numeral 33 denotes control means for controlling the operation of the entire apparatus.
6, the magnetron drive power supply 13, the impedance variable means 19,
The operation of each of the 20 dielectric rotation driving means is controlled. Reference numeral 34 denotes a door that opens and closes when an object to be heated is taken in and out of the heating chamber 10.

Next, an operation procedure and control contents according to an embodiment of the present invention using the apparatus having the above configuration will be described with reference to FIGS.

FIG. 3 shows the flow of control contents up to the start of heating, and FIG. 4 shows the flow of control contents in this embodiment. In FIG. 4, the control content has three stages.

First, the first stage will be described. In the first stage, the presence or absence, the number, and the temperature of the object to be heated are detected. The second stage controls the impedance variable means and the magnetron based on the result obtained in the first stage and the temperature change of the object to be heated, and the third stage ends the heating after the object to be heated reaches a predetermined temperature.

In FIGS. 3 and 4, an object to be heated is placed in a heating chamber 1.
After being stored and mounted on the mounting table 11 in the area 0, the user determines a heating condition for heating the object to be heated and selects a heating item of the operation unit 26 (S101). Next, after inputting the heating time (designated at 29 in FIG. 1) or the desired heating end temperature (designated at 28 in FIG. 1), the user presses the "start" key 30 shown in FIG. 1 (S102). Thus, dielectric heating of the object to be heated is started. Step S103 is for confirming that the "start" key 30 has been pressed, and the "cancel" key 31 is provided prior to the "start" key 30.
When is pressed, the process returns to S101. In the selection of the input item, if the "warm" key or the "thaw" key, which is an automatic cooking item, is selected, the process proceeds to S102 without inputting the heating time.

In step S104, the control means 33 determines whether the cooking is automatic heating cooking or manual heating cooking. If it is determined in S104 that the cooking is automatic heating, the process proceeds to S105. On the other hand, if it is determined that the cooking is manual heating cooking, the process proceeds to S106 (). In S101, when the end temperature of the object to be heated is set and input, the control unit 33 stores the set temperature. In S105, the temperature of the entire mounting table (hereinafter referred to as the mounting surface) is measured by the infrared sensor 25, and it is determined whether or not the object to be heated is mounted from the low-temperature portion and the high-temperature portion. If the temperature at the measurement point is lower or higher than the average temperature of the mounting surface by more than a predetermined temperature, it is determined that a low-temperature food or a food that is higher than normal temperature is mounted. Is determined to be placed, or the food is not placed. In this embodiment, the predetermined temperature is 5 ° C. In step S107, the number of foods to be placed is determined based on the number of portions that are lower or higher than the temperature of the placement surface. In the case where the number of mounting is plural in S107, S1
08, otherwise proceeding to S109. S10
In step 9, the impedance variable means (hereinafter referred to as IMP) is controlled so that the microwaves are dispersed. In this embodiment, the IMP is controlled to 15 * / IR / 3 *, the magnetron is operated in S110, and dielectric heating is started. In S111, the temperature of the mounting surface is measured again and stored as the initial temperature.

In S112, it is determined whether or not a predetermined time set in advance as a temperature measurement period has elapsed. If the temperature has not reached, the heating is continued. If the temperature has reached, the process proceeds to S113, and the temperature of the mounting surface is reduced. Measure. In S114, the difference between the temperature at each measurement point obtained in each measurement cycle and the temperature at the time of the immediately preceding measurement is set as the temperature rise value of the object to be heated. Hereinafter, this numerical value is referred to as DIF. In step S115, the number of objects to be heated is determined again based on the measured value in step S113. In this determination, the DIF value is used. In this example, 3 ° C. was used as the DIF value. When the DIF is equal to or higher than 3 ° C., it is determined that the object to be heated has generated heat due to the microwave, and the placement position and the number of the objects to be heated are determined from the number of portions where the DIF has changed. If it is determined that there is a plurality of objects to be heated, S108
Otherwise, the process proceeds to S116.

In S116, if the highest value of the detected temperature has reached the heating end temperature, the process proceeds to the third stage. If it has not reached, the process proceeds to S117. In S117, it is determined whether or not the first stage upper limit time has been reached. If it has reached, the process proceeds to S118 (). If it has not reached, the process returns to S112 and continues to determine the number of objects to be heated while continuing heating. Here, the first stage upper limit time varies according to the microwave output. For example, if the microwave output is 8
For 00W and 600W, the upper limit time is 2 minutes 30 minutes each
Set to seconds and 3 minutes.

Next, the second stage will be described. The second stage is control when it is determined that there are a plurality of objects to be heated or that heating unevenness has occurred in a single object to be heated. In the second stage, first, the operation of the magnetron is checked in S119, and if it is stopped, the magnetron is operated (S120). In S121, it is determined whether the temperature distribution on the mounting surface is uniform. If the temperature difference at the mounting position where the object to be heated is determined to be present is less than a predetermined value, or if the difference in DIF at the position where each object to be heated is less than a predetermined value, it is determined that the temperature distribution is uniform. The heating is continued while controlling the IMP so that the microwaves are dispersed (S1).
22). On the other hand, if the temperature difference or the difference between the temperature rise values DIF exceeds a predetermined value, it is determined that the temperature distribution is not uniform, and the process proceeds to S123, where the IMP is controlled so that the microwave is deflected to the lower temperature side of the object to be heated. . In this embodiment, the IMP control pattern for deflecting the microwave to the left is 15 * /
IR / 0. This control pattern can be changed.

In S124, it is determined whether or not a predetermined time has elapsed. If the predetermined time has elapsed, the current heating is continued, and if the predetermined time has elapsed, the flow proceeds to S125. S12
In step 5, the current temperature of the object to be heated is detected. In S126, it is determined whether or not the maximum temperature of each object to be heated has reached the end temperature, and if not, the process returns to S121 to continue heating. If it is determined in S126 that the maximum temperature of each object to be heated has reached the end temperature, the process proceeds to the third stage.

In the third stage, the operation of the magnetron is stopped in S127, and in S128, the support angle of the dielectric plate is set to 0 ° to reset the IMP, and the heating is ended.

Next, control when manual heating is determined in S104 will be described with reference to FIG.

In S151, based on the manual heating input information from the operation unit 26, the rotation driving means of the dielectric plate is operated to set the dielectric plate to a desired support angle and a desired rotation speed.
When the support angle is set, the support angle of the dielectric plate is set to 0.
After detecting the position of ゜, the dielectric plate is set to a predetermined support angle or rotation speed, and heating is started.
If it is determined in S152 that the heating time has been input as the heating information, the process proceeds to S153, where the elapsed heating time and the end time are compared. On the other hand, if it is determined in S152 that the end temperature has been input, the process proceeds to S154, where the temperature on the mounting surface is detected, and the current temperature of the object to be heated is fetched. Thereafter, in S155, the maximum value of the temperature information fetched in S154 is compared with the end temperature.

When the elapsed heating time reaches the end time set in S153 or the maximum temperature detected in S155 reaches the end temperature set in S155, S1 is reached.
Proceeding to 56, the operation of the magnetron is stopped, and in S157, the support angle of the IMP is reset to 0 °, and the heating is ended.

In parallel with the above-mentioned control contents, the microwave output during heating can be controlled based on the input conditions in response to exceeding a specified elapsed time or a specified temperature. .

Next, the control when the first stage upper limit time is reached in S117 and it is determined that the object to be heated is singular or not placed will be described with reference to FIG.

If it is determined in step S201 that there is an object to be heated, the flow advances to step S202 to measure the temperature of the mounting surface. In this case, it is determined that the number of objects to be heated is one. If it is determined in S203 that one heated object has a high-temperature portion and a low-temperature portion, the process proceeds to S118 (). If it is determined in S203 that the temperature distribution is uniform, the process proceeds to S204. In S204, it is determined whether a predetermined time has elapsed. If the predetermined time has not been reached, the current heating is continued. If the predetermined time has been reached, the process proceeds to S205, where the current temperature of the object to be heated is detected. Thereafter, in S206, it is determined whether or not the maximum temperature of the object to be heated has reached the end temperature. If not, the process returns to S203, and if it has, the process proceeds to the third stage.

In the third stage, the operation of the magnetron is stopped in S207, the support angle of the IMP is reset to 0 ° in S208, and the heating is ended.

On the other hand, if it is determined in step S201 that there is no change in the value of DIF and there is no object to be heated, step S301 is performed.
Then, in S301, notification of the stop of heating is performed. This notification uses an electronic sound or lighting, blinking, or changing the emission color of a light emitting unit such as a lamp or an LED.

In S302, the operation of the magnetron is stopped, and in S302, the support angle of the dielectric plate of the IMP is reset to 0 °. Thereafter, in step S304, a display indicating that heating has been stopped is displayed in the operation unit, and the heating is terminated. At this time, the notification buzzer or the like may be operated before or during the display of the heating stop.

The rotation speed of the IMP can be changed according to the object to be heated.

Next, control contents of an actual operation example using a specific object to be heated will be described. Table 1 shows that when the object to be heated was placed on a plate with one frozen rice and one chilled hamburger, each placed on the left and right sides of the mounting table when viewed from the door side of the heating chamber, and heated at the same time and finished heating at the same temperature. 3 shows the control of the temperature change of the measurement point and the impedance variable means.

[0058]

[Table 1]

CURRENT is temperature distribution data obtained by the control processing corresponding to S111 in FIG. 4, and represents the temperature of the measurement points in the entire mounting table. In this embodiment, the control is performed with each measurement row as one range. In each measurement row, the first is the left end and the 16th is the right end in the refrigerator.

MAX and AVE indicate the maximum temperature and the average temperature of each measurement row, respectively, and the portion lower than the average temperature by 5 ° C. or more is shown in bold. DIF indicates the difference between the AVE every 10 seconds of heating and the immediately preceding AVE.

Immediately after the start of heating, the impedance variable means was controlled at 15 * / IR / 3 *. The absolute value of the detected temperature in the third to fifth columns is lower than the other regions and A
VE is lower than the average temperature of the whole by 5 ° C. or more, indicating that the low-temperature food was placed on the left side of the refrigerator.

Since there is no change in both MAX and DIF up to 60 seconds of heating, heating is continued without changing the control conditions of the impedance variable means.

After heating for 60 seconds, the DIF on the right side of the refrigerator was 3 ° C.
From the above, it can be determined that food is placed on the right side, and as a result, it is recognized that there are a plurality of objects to be heated. It can also be seen that the food on the right has a higher absolute temperature than the food placed on the left and the temperature rises faster than the food on the left. Portions where the DIF is 3 ° C. or higher are in bold. FIG.
In the processing of S121, it can be determined that the temperature distribution is not uniform, and I
Change MP to 15 * / IR / 0.

Thereafter, heating is continued based on a predetermined control process while monitoring the temperatures of the two foods on the mounting surface at a cycle of 10 seconds. In this case, since the temperature of the food on the left is lower than the temperature of the food on the right, the microwave deflection is maintained all the way to 270 seconds after heating.

After 270 seconds of heating, it is determined that the maximum temperature of both the left and right foods has reached the end temperature, and the heating is terminated. In Table 1, the maximum temperature is shown in bold.

At this time, the temperature ranges at the end of heating of the frozen rice and the chilled hamburger are 85.6 to 97.9, respectively.
C, 87.8-94.0C.

In this embodiment, the IMP is changed only once. However, an optimum control is selected from among a plurality of IMP control conditions provided in advance in accordance with the temperature distribution at the time of the heating. The IMP may be changed many times until the maximum temperature of the object to be heated reaches the end temperature. In addition, the microwave output in the present embodiment was 600 W, but as the microwave output increased or decreased, the temperature measurement cycle of the object to be heated was changed in conjunction with the control so that more precise control in accordance with the degree of temperature rise was achieved. It can be performed.

As described above, the temperature distribution on the mounting surface is periodically detected to detect the initial temperature or the temperature change of the object to be heated, and the presence or absence of the object to be heated or the number of the objects to be heated can be determined. By controlling the impedance variable means according to the temperature of the object to be heated and dispersing or deflecting the microwave, even if a plurality of objects with different initial temperatures are heated without moving the object to be heated, they are heated at the same temperature I was able to finish.

In this embodiment, the long axis direction of the opening portions 17 and 18 is parallel to the width direction of the heating chamber 10.
It may be arranged in any direction as long as it disturbs the flow of the high-frequency current, and may be arranged on any wall surface.
Also, the number of arrangements is not limited to two. Further, in this embodiment, the infrared sensor is provided on the rear surface of the refrigerator, but may be provided on the upper surface or the side surface of the refrigerator.

[0070]

As described above, according to the first to eighth aspects of the present invention, the impedance of the wall of the heating chamber is controlled based on the temperature distribution, and the microwave is quickly deflected and concentrated in a low temperature region. A plurality of objects to be heated can be simultaneously finished at a desired temperature by suppressing temperature unevenness.

According to the microwave heating method of the ninth and tenth aspects, waste of power consumption when there is no object to be heated is suppressed, and deterioration of the magnetron is prevented. Further, the user can recognize that the heating has stopped because there is no object to be heated, and the usability can be improved.

[Brief description of the drawings]

FIG. 1 is an external configuration diagram of a microwave heating apparatus of an embodiment using a microwave heating method of the present invention.

FIG. 2 is a side view of the microwave heating apparatus shown in FIG. 1;

FIG. 3 is a flowchart of control contents up to the start of heating in the microwave heating method according to the embodiment of the present invention.

FIG. 4 is a flowchart of control contents of a microwave heating method according to an embodiment of the present invention.

FIG. 5 is a flowchart of control contents of manual processing of the microwave heating method according to the embodiment of the present invention.

FIG. 6 is a flow chart of control contents when the object to be heated is singly or not placed in the microwave heating method according to the embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 heating chamber 11 mounting table 12 magnetron (microwave generating means) 13 magnetron drive power supply 17, 18 opening 19, 20 impedance variable means 23 motor (impedance variable means) 25 infrared sensor (temperature detecting means) 26 operating section 27 display Means 33 Control means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 6/64 H05B 6/64 D 6/68 320 6/68 320Q (72) Inventor ▲ Hane ▼ Takeshi Tano 1006 Kazuma, Kadoma, Osaka Prefecture F-term (reference) in Matsushita Electric Industrial Co., Ltd. CA24 EA02 EB02 EB14 EB35 3L086 AA01 BA08 BB05 BB08 CA11 CA16 CB05 CB08 CB16 CB20 CC03 CC08 CC14 DA12 DA16 DA24 DA27

Claims (10)

[Claims] 1. A first step of detecting a temperature distribution on a mounting surface on which an object to be heated is mounted and determining the position of the object to be heated, and a temperature of the mounting surface detected at a predetermined cycle time. When the maximum value of the distribution information is lower than the heating end temperature, the second stage of deflecting the microwave to a low temperature region to make the temperature distribution uniform, and heating when the maximum value of the temperature information is equal to or higher than the heating end temperature. And a third step of terminating the process. 2. A method of deflecting microwaves comprises increasing an impedance value of an opening provided to cut off a flow of a high-frequency current flowing through a wall surface of a heating chamber for accommodating an object to be heated. 2. The microwave heating method according to claim 1, wherein the flow is suppressed. 3. The microwave heating method according to claim 1, wherein the cycle time is changed in conjunction with the microwave output. 4. The microwave heating method according to claim 1, wherein the determination of the position of the object to be heated is made based on an absolute value of the detected temperature or a temperature rise value within a predetermined time. 5. The microwave heating method according to claim 1, wherein the microwave is dispersed until the determination of the number of objects to be heated is completed. 6. A method for dispersing microwaves includes changing the impedance value of an opening portion arranged so as to cut off the flow of a high-frequency current flowing through a wall surface of a heating chamber for accommodating an object to be heated with time. 6. The microwave heating method according to claim 5, wherein the flow of the high-frequency current is varied. 7. The method according to claim 1, wherein in the first step, when the number of objects to be heated is determined to be plural and the temperatures of the respective objects to be heated are different, the microwave is deflected toward the object to be heated having the lowest temperature. Microwave heating method. 8. The method according to claim 1, wherein in the first step, if the number of objects to be heated is not determined to be plural within the upper limit time of the first step and the temperature distribution is non-uniform, the microwave is deflected to a low temperature region. Item 3. The microwave heating method according to Item 1. 9. The microwave heating method according to claim 1, wherein in the first step, when it is determined that there is no object to be heated, the user is notified that microwave heating is to be stopped and the heating is stopped. 10. The microwave heating method according to claim 9, wherein it is determined that there is no object to be heated, and after the microwave heating is stopped, it is displayed that it is determined that there is no object to be heated.