JPH09119649A - Electronic oven range - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a proper heating constantly corresponding to a difference in the initial temperature of an object to be heated in the executing of a thawing/cooking operation. SOLUTION: In the thawing/cooking operation, the behavior of a moisture sensor varies depending on the passive capacity of an object to be heated (the degree of heating energy necessary for thawing the frozen object to be heated), small (a), medium (b) and large (c). Utilizing this, a detection value α of the moisture sensor is read when time Tα passes from the start of heating to judge the passive capacity of the object to be heated divided into three stages. Residual time coefficient β is determined based on the detection value α and the residual heating time Tβ is set to a value obtained by multiplying the specified time by the residual time coefficient β. Thus, the shorter the heating time, the smaller the passive capacity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave oven having a function of thawing and thawing frozen food.

[0002]

Generally, in a microwave oven, frozen foods such as tuna sashimi and minced meat,
It has a function of thawing cooking (raw thawing) for thawing thinly sliced meat, etc. When the user turns on the dedicated thawing key on the operation panel, the control circuit such as the microcomputer thaws according to the cooking program for thawing Is designed to run. In this thawing cooking, the control circuit sets the heating time according to the weight of the food (object to be heated) detected by the weight sensor, and the heating is automatically terminated when the heating time has elapsed. Was there.

However, in the case of controlling the heating of the thawing cooking based only on the weight of the food as described above, there is a problem that the difference in the initial temperature of the frozen food cannot be dealt with. That is, the initial temperature of frozen food is -18 ° C.
It is generally before and after, and the heating output (energy) is set in advance assuming that this -18 ° C food is 0 ° C to 10 ° C. However, when the initial temperature of the food is relatively high, the food may be overheated and boiled.

By the way, in recent years, it has been a general practice to provide a gas sensor (gas sensor) for detecting a gas such as water vapor generated from food in a microwave oven and automate "warming" cooking based on the detection by the gas sensor. Is becoming.

Here, for example, in Japanese Unexamined Patent Publication No. 6-74458, foods at room temperature or frozen foods are roughly classified based on the detection of the gas sensor before the start of cooking, and heating is controlled according to the discrimination. Is proposed. Further, Japanese Patent Publication No. 5-1806 discloses a technique of sequentially controlling the frozen food from thawing to cooking using a gas sensor. However, these do not solve the above-mentioned problems.

The present invention has been made in view of the above circumstances, and an object of the present invention is to always perform appropriate heating because it is possible to cope with the difference and the amount of the initial temperature of the object to be heated when performing the thawing cooking. It is to provide a microwave oven that can.

[0007]

According to a first aspect of the present invention, there is provided a microwave oven in which a material to be heated is accommodated and heating means for supplying microwaves to the heating chamber to heat the material to be heated. A ventilation device for performing forced ventilation in the heating chamber, a gas sensor for detecting a gas such as water vapor generated from the object to be heated, and the object to be heated which is being heated by the heating means at the time of performing defrosting cooking. It is characterized in that it comprises a defrosting control means for judging the heated capacity of the object to be heated based on the detection of the gas sensor under a frozen state and controlling the heating means according to this judgment.

Here, the heated capacity represents the degree of the heating energy required for thawing the frozen object, and the larger the capacity (weight) of the heated object, the greater it becomes. Further, the lower the initial temperature of the object to be heated, the larger it becomes. The present inventor, when the object to be heated in a frozen state is accommodated in the heating chamber and thawing cooking is started, the object to be heated is at a low temperature under the frozen state of the object to be heated after the start of cooking. , Paying attention to the fact that the temperature inside the heating chamber gradually decreases and the amount of water vapor contained in the air inside the heating chamber (in other words, humidity) decreases accordingly. , The time when the detection value of the gas sensor fluctuates in the negative direction is longer than that at the start of cooking,
Further, they have found that the range of fluctuation in the negative direction is large, and have accomplished the present invention.

In the present invention, the above defrosting control means is
The whole heating time can be set according to the heated capacity of the object to be heated (the invention of claim 2). Further, the thawing control means can be configured to determine the heated capacity of the object to be heated based on reading the detection value of the gas sensor when a certain time has elapsed from the start of heating by the heating means (claim 3 In addition, the defrosting control means may be configured to read the detection values of the gas sensor at a plurality of different time points and determine the heated capacity of the object to be heated based on the plurality of detection values. (Claim 4
Invention).

Further, the defrosting control means can be configured so that the remaining heating time after the determination of the heated capacity of the object to be heated is lengthened as the detected value of the gas sensor fluctuates in the negative direction. , (Invention of claim 5), defrosting control means,
The heating output in the remaining heating time after the determination of the heated capacity of the object to be heated may be changed according to the heated capacity (the invention of claim 6).

Further, a temperature sensor for detecting the temperature in the heating chamber is provided, and the thaw control means is corrected such that the higher the temperature detected by the temperature sensor at the start of heating, the earlier the time point for determining the capacity to be heated. If it is configured to do so, it will be more effective (the invention of claim 7), and the temperature sensor for detecting the temperature in the heating chamber is provided, and the defrosting control means can detect the temperature detected by the temperature sensor at the start of heating. The higher the temperature, the smaller the heating output of the heating means may be corrected (the invention of claim 8).

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention (corresponding to claims 1, 2, 3, 5, and 7) will be described below with reference to FIGS. 1 to 7. First, FIGS. 4 and 5 show the structure of the microwave oven according to the present embodiment, in which the heating chamber 2 is provided in the main body 1 of the microwave oven. A turntable 3 is provided at the bottom of the heating chamber 2,
An object to be heated A such as sashimi in a frozen state is placed on the turntable 3. The turntable 3 is rotated by a motor 4 provided at the outer bottom portion of the heating chamber 2. Also, the main body 1
A door 5 for opening and closing the front opening of the heating chamber 2 is provided on the front surface of the.

Inside the main body 1, a machine room 6 is provided on the right side of the heating room 2. In this machine room 6,
A magnetron 7 which constitutes a heating means is provided, and a cooling fan 8 for cooling the magnetron 7 is provided. The microwave oscillated from the magnetron 7 is supplied into the heating chamber 2 via a waveguide (not shown), so that the object A to be heated is cooked.

An operation panel 9 is provided on the front surface of the machine room 6.
Is provided, and a control circuit 10 including a microcomputer is provided on the back side of the operation panel 9. As partially shown in FIG. 3, the operation panel 9 has a raw defrosting key 1
1 and a large number of operation keys such as the start key 12 and the display unit 1
3 are provided.

A blower port 14 is provided on the right wall portion of the heating chamber 2, and a duct connecting the blower port 14 and the intake port 15 opened on the right side of the main body 1 is provided in the machine chamber 6. 16 are provided. A ventilation fan 17 as a ventilation device is arranged in the duct 16. On the other hand, an exhaust port 18 is provided in the left wall portion of the heating chamber 2, and an exhaust duct 20 that connects the exhaust port 19 opening at the rear surface of the main body 1 and the exhaust port 18 to the outer wall portion of the heating chamber 2 is provided. It is provided. With this, the ventilation fan 1
When 7 is driven, the outside air is supplied into the heating chamber 2 through the duct 16 and the air in the heating chamber 2 is discharged through the exhaust duct 20, so that the forced ventilation in the heating chamber 2 is performed. To be seen.

A gas sensor for detecting a gas such as water vapor generated from the object A to be heated is provided in the exhaust duct 20. In this embodiment, as this gas sensor, a humidity sensor (absolute humidity sensor) 21 that detects the amount (concentration) of water vapor contained in the air is adopted. As shown in FIG. 6, the humidity sensor 21 has a sensor case 22 integrally provided with a closed case portion 22a and an open case portion 22b, and the closed case portion 22a and the open case portion 22b are both made of a thermistor. The first and second humidity detecting elements 23 and 24 are arranged respectively.

The first and second humidity detecting elements 23 and 24 are both heated to a high temperature of about 200.degree.
At this time, the first humidity detecting element 23 is
Since it is hermetically sealed in the dry air inside 2, the constant heat is radiated regardless of the outside air, whereas the second humidity detecting element 24 is provided inside the open case portion 22b through which the outside air can flow. The amount of water contained in the outside air (humidity)
Therefore, the amount of heat radiation changes.

The first and second humidity detecting elements 23 and 24 are arranged in the humidity detecting circuit 2 as shown in FIG.
It forms part of 5. The humidity detecting circuit 25 includes the first and second humidity detecting elements 23 and 24 between the terminals of the DC power source 26 having a capacity sufficient to generate heat.
The humidity detecting elements 23 and 24 and the resistors 27 and 28 are bridge-connected, and the respective connection points are connected to the input terminal of the amplifier 29. Thereby, the detection signal of the voltage level corresponding to the absolute humidity in the exhaust duct 20 is output from the output terminal 29a of the amplifier 29.

Further, in this embodiment, as shown in FIG. 5, a temperature sensor 30 for detecting the temperature in the heating chamber 2 is provided on the inner wall of the heating chamber 2. FIG.
1 schematically shows an electrical configuration centered on the control circuit 10, into which the detection signal of the humidity sensor 21 and the detection signal of the temperature sensor 30 are input. Signals from various keys of the operation panel 9 are input. And the control circuit 1
0 controls the energization of the magnetron 7, the cooling fan 8, the motor 4, and the ventilation fan 17 to perform heating and cooking based on the built-in control programs and their input signals, and the display of the display unit 13 is also displayed. It is designed to be controlled.

At this time, as will be described in detail later in the description of the operation, the control circuit 10 functions as a thawing control means by its software configuration, and when thawing cooking is performed,
Based on the detection of the humidity sensor 21 at the time when a predetermined time has elapsed from the start of heating (when the object to be heated A is still in a frozen state), the heated capacity of the object to be heated A (the object to be heated A is thawed). The degree of heating energy required for
Is determined and the magnetron 7 is controlled according to the determination. In this case, the heating time is controlled. Further, in the present embodiment, the time of detection by the humidity sensor 21 (determination of the heated capacity) is changed according to the temperature in the heating chamber 2 detected by the temperature sensor 30 at the start of defrosting and cooking. There is.

Next, the operation of the above structure will be described with reference to FIGS. 1 and 2. When the user wants to thaw and cook an object A to be heated such as frozen tuna sashimi, the user places the object A to be heated on the turntable 3 and closes the door 5, and then the operation panel 9 The raw thawing key 11 is operated to select thawing cooking, and the start key 12 is continuously turned on.

In this thawing cooking, the object A to be heated in the frozen state (generally -18 ° C) is thawed to 0 ° C to 10 ° C, but basically, as shown in part in Fig. 1. First, there is a cleaning operation in which the ventilation fan 17 is driven for a short time to ventilate the inside of the heating chamber 2, and then the magnetron 7 and the cooling fan 8 are turned on and the motor 4
Is turned on, the turntable 3 is rotationally driven, and the heating operation is started. Then, when the object A to be heated is thawed to 0 ° C to 10 ° C, the heating operation is ended. At this time, the magnetron 7 is energized to repeat, for example, 15 seconds of energization and 15 seconds of interruption.

Here, it goes without saying that the larger the weight (volume) of the article A to be heated, the longer the heating time, but in addition to that, depending on the initial temperature of the article A to be heated,
The appropriate heating time will vary. That is, when the initial temperature of the object to be heated A is relatively high, such as −5 ° C. or −10 ° C., unless the heating time is set short, the object will be overheated.

The inventor has introduced the concept of the heated capacity of the object to be heated A and has found that the heated capacity of the object to be heated A can be determined by the humidity sensor 21. The heated capacity represents the degree of heating energy required for thawing the frozen object A, which increases as the weight (volume) of the object A increases, and The lower the initial temperature of the heated product A, the larger the temperature. Then, as shown in FIG. 1, during thawing cooking, the behavior of the humidity sensor 21 varies depending on whether the heated capacity of the object to be heated A is small (see a), medium (see b), or large (see c). Will be different.

This is because when the object A to be heated in a frozen state is housed in the heating chamber 2 and the thawing cooking is started, the object A to be heated is in a frozen state (starting from the object A to steam). In a state in which almost no heat is generated), the temperature inside the heating chamber 2 decreases due to the low temperature of the object to be heated A, and the amount of water vapor contained in the air inside the heating chamber 2 decreases accordingly ( In other words, this is considered to be due to the phenomenon that the humidity decreases. Therefore, the larger the heated capacity of the object to be heated A, the longer the detection value of the humidity sensor 21 fluctuates in the negative direction than that at the start of cooking, and the larger the fluctuation range in the negative direction.

Therefore, in this embodiment, the control circuit 10
According to the procedure shown in the flowchart of FIG. 2, the heating capacity of the object A to be heated is determined and the heating time is set. That is, when the start key 12 is turned on, first, in step S1, the temperature t in the heating chamber 2 is detected by the temperature sensor 30, and the correction coefficient K is determined based on the detected temperature t. The correction coefficient K is for determining the time point for determining the capacity to be heated, and as shown in the figure, has a smaller value as the detected temperature is higher.

When the start key 12 is turned on, the cleaning operation for ventilating the inside of the heating chamber 2 is performed as described above. As shown in FIG. 1, this cleaning operation ends and heating cooking starts. In the meantime,
The ventilation fan 17 is temporarily stopped, at this time, the detection value of the humidity sensor 21 is read, and this detection value is set to the reference value (0 V) (step S2). Then, the heating operation is started (step S3).

Then, when a predetermined time Tα has elapsed since the heating operation was started (time 0) (Yes in step S4).
s), in step S5, the detection value α of the humidity sensor 21 is read. At this time, the predetermined time Tα is a time obtained by multiplying the correction coefficient K by, for example, 120 seconds, and as described above, the higher the initial temperature of the heating chamber 2, the earlier the capacity determination time point. It has become.

Here, as shown in FIG. 1, the heated capacity of the object to be heated A can be determined by the detected value α of the humidity sensor 21 after a lapse of a predetermined time Tα from the start of heating. That is, when the humidity in the heating chamber 2 decreases, the larger the heated capacity of the object to be heated A, the longer the time when the detected value of the humidity sensor 21 changes in the negative direction than when the cooking is started, and The fluctuation range in the negative direction becomes large. In the present embodiment, when the detected value α of the humidity sensor 21 is less than -1V, it is determined that the heated capacity is large, and when it is -1V or more and 0V or less, the heated capacity is determined to be medium and exceeds 0V. When it is, it is determined that the heated capacity is small.

In step S6, the remaining time coefficient β is determined based on the detected value α. This remaining time coefficient β is
When α <-1V (large heated capacity) 3, -1V ≤ α ≤ 0
It is determined as 2 when V (medium volume to be heated) and 1 when 0V <α (small volume to be heated). Then, in step S7, the total heating time T (remaining heating time Tβ) is set.
In this case, the remaining heating time Tβ is set to a value obtained by multiplying the predetermined time Tα by the remaining time coefficient β, so that the total heating time T becomes Tα + Tβ.

After that, while the remaining heating time is displayed on the display unit 13, the time is counted down (step S
8) When the remaining heating time Tβ has elapsed (Yes in step S9), the magnetron 7, the cooling fan 8, the ventilation fan 17, and the motor 4 are turned off, and the heating operation is ended (step S10).

As a result, when the heated capacity is large, the heating time is long, and when the heated capacity is small, the heating time is short, and the defrosting cooking is performed at the heating time corresponding to the heated capacity of the object A to be heated. It is possible to carry out the thawing and cooking, so that appropriate thawing cooking according to the weight (volume) of the object to be heated A and the initial temperature is carried out. Although detailed description is omitted, it is needless to say that the microwave oven of this embodiment can perform warming cooking and the like. For example, in warming cooking, the humidity sensor 21 detects the amount of steam generated from food,
The heating is controlled based on the detected value.

As described above, according to the present embodiment, the fact that the detected value of the humidity sensor 21 behaves differently depending on the heated capacity of the object A to be heated during the progress of heating during the thawing cooking, The heating capacity of the object A to be heated is determined and the heating time is set. Therefore, unlike the conventional method in which the heating control of the thawing cooking is performed only based on the detection of the weight sensor, it is possible to cope with the difference in the initial temperature of the object to be heated A and always perform appropriate heating. It is possible. Further, since the humidity sensor 21 (gas sensor) used for controlling the warming can be used as it is, it is possible to do without increasing the number of parts or complicating the configuration, and the weight sensor which has been conventionally required. You don't have to use.

Further, particularly in the present embodiment, the temperature t in the heating chamber 2 is detected by the temperature sensor 30 at the start of cooking, and the time point Tα for capacity determination is corrected based on the detected temperature t. It is possible to cope with fluctuations in the detection value of the humidity sensor 21 due to the influence of the initial temperature in the heating chamber 2 (the higher the initial temperature in the heating chamber 2, the faster the humidity rises), and more reliably. The heated capacity of A can be determined, and more appropriately thaw cooking can be performed.

In the first embodiment described above, the heated capacity of the object A to be heated is determined in three stages of large, medium and small. However, the second embodiment shown in FIG. (Corresponding to item 4), the detection value of the humidity sensor 21 is read at a plurality of different time points, so that it is possible to make a more detailed determination.

That is, as shown in FIG. 8 (a), first, when Tα1 hour (for example, 120 seconds) has elapsed from the start of heating, the detected value α1 of the humidity sensor 21 is read, and based on the detected value α1, As in the first embodiment, the heated capacity is roughly classified into large, medium, and small. Then, when Tα2 hours (for example, 180 seconds) have elapsed from the start of heating, the detection value α2 of the humidity sensor 21 is read, and based on the detection value α2, the large classified medium is further divided into large, medium and small. Classify. FIG. 8B shows a state in which the large classification of the heated capacity is determined to be medium based on the detected value α1, and further subdivided into three stages of medium large, medium medium and small. .

Therefore, as a whole, it is judged which of the nine heated capacities is classified, and the heating time is set according to the judgment. In this way, by further subdividing the determination of the heated capacity,
The accuracy of determination of the heated capacity is increased, and more precise heating control can be performed. It should be noted that the capacity to be heated may be determined in two steps or in four or more steps based on the detection value α of the humidity sensor 21 once, and the reading may be performed in three steps.
If it is performed more than once, it is possible to perform the defrosting cooking with more precise control.

FIG. 9 shows a third embodiment of the present invention (claim 8).
Corresponding to). In this embodiment, the heating output is changed by changing the energization pattern to the magnetron 7 based on the temperature t detected by the temperature sensor 30 at the start of cooking, that is, the higher the detected temperature t, the smaller the heating output. I am trying to make corrections.

That is, when the detected temperature t is less than 20 ° C., the magnetron 7 is repeatedly energized for 20 seconds and disconnected for 10 seconds, and when the detected temperature t is 20 ° C. or more and 50 ° C. or less, energized for 15 seconds, for example. When the detected temperature t exceeds 100 ° C. after repeating the power interruption for 15 seconds, the power supply is repeated for 10 seconds and 20 seconds, for example. According to this, regardless of whether the initial temperature in the heating chamber 2 is high or low, the object A to be heated can be stably heated.

In the above embodiment, the correction is made based on the detection of the initial temperature t in the heating chamber 2 of the temperature sensor 30, but the reading time Tα of the humidity sensor 21 is a fixed time (for example, 120 seconds). ) May be fixed, and in this case, it can be applied to a microwave oven without the temperature sensor 30. Further, although the absolute humidity sensor 21 is adopted as the gas sensor in the above embodiment, a general gas sensor (humidity sensor) in which the resistance value of the semiconductor element changes according to the amount (concentration) of gas such as vapor or alcohol is used. It can also be adopted. Further, in the above embodiment, the heating time is changed based on the determination of the capacity to be heated, but it is also possible to change the heating output in the remaining heating time.

In addition, for example, when applied to a microwave oven equipped with a weight sensor, the reading time Tα of the humidity sensor 21.
May be changed according to the weight, and the ventilation fan 17 dedicated to ventilation is provided, but the cooling fan may also be used for ventilation. Moreover,
The present invention is applicable to a microwave oven that also has the functions of an oven and a grill, and can be appropriately modified and implemented without departing from the scope of the invention.

[0042]

As is apparent from the above description, the present invention has the following excellent effects. That is, according to the microwave oven of claim 1, the concept of the heated capacity of the object to be heated is introduced, and the larger the heated capacity at the time of thawing cooking, the more negative the detection value of the gas sensor becomes than that at the start of cooking. Based on the knowledge that the fluctuation time is long and the fluctuation range in the negative direction becomes large, a gas sensor is provided and the heated capacity of the object to be heated is determined based on the detection of the gas sensor during defrosting and cooking. Since the thawing control means for controlling the heating means according to the judgment is provided, when performing the thawing cooking, it is possible to cope with the amount of the object to be heated and the difference in the initial temperature and always perform appropriate heating. It is possible.

In this case, the thawing control means may be configured to set the entire heating time according to the heated capacity of the object to be heated (microwave oven according to claim 2), or the thawing control means It is effective if the heating capacity of the object to be heated is determined based on the reading of the detection value of the gas sensor at the time when a certain time has elapsed from the start of heating by the heating means (microwave oven of claim 3). .

Further, the thawing control means may be configured to read the detection values of the gas sensor at a plurality of different time points and determine the heated capacity of the object to be heated on the basis of the plurality of detected values. 4), the heated capacity of the heated object can be determined with higher accuracy.

Further, the thawing control means may be configured to extend the remaining heating time after the determination of the heated capacity of the object to be heated as the detected value of the gas sensor fluctuates in the negative direction. The microwave oven of 5) and the thawing control means are configured to change the heating output in the remaining heating time after the determination of the heated capacity of the object to be heated according to the heated capacity (the microwave oven of claim 6). ), Appropriate thawing cooking can be performed according to the heated capacity of the heated object.

A temperature sensor for detecting the temperature in the heating chamber is provided, and the thaw control means is corrected such that the higher the temperature detected by the temperature sensor at the start of heating, the earlier the time point for determining the capacity to be heated. If configured to perform (microwave oven according to claim 7), the heated capacity can be reliably determined without being affected by the initial temperature in the heating chamber.

Further, a temperature sensor for detecting the temperature in the heating chamber is provided, and the thaw control means is adapted to make a correction such that the heating output by the heating means is reduced as the temperature detected by the temperature sensor at the start of heating is higher. With this configuration (the microwave oven according to claim 8), stable heating of the object to be heated can be performed regardless of whether the initial temperature in the heating chamber is high or low.

[Brief description of the drawings]

FIG. 1 shows the first embodiment of the present invention, and is a diagram showing the behavior of the humidity sensor with the lapse of time during defrosting and cooking.

FIG. 2 is a flowchart showing a procedure for determining a heated capacity and setting a heating time.

FIG. 3 is a block diagram showing an electrical configuration.

FIG. 4 is a vertical sectional front view of the microwave oven.

FIG. 5 is a transverse plan view of the microwave oven.

FIG. 6 is a sectional view of the humidity sensor.

FIG. 7 is a diagram showing a configuration of a humidity detection circuit.

FIG. 8 shows a second embodiment of the present invention, and is a diagram showing the behavior of the humidity sensor over time during defrosting and cooking.

FIG. 9 is a diagram showing a third embodiment of the present invention and showing an energization pattern to a magnetron.

[Explanation of symbols]

In the drawings, 1 is a main body, 2 is a heating chamber, 7 is a magnetron (heating means), 9 is an operation panel, 10 is a control circuit (defrosting control means), 11 is a raw defrosting key, 12 is a start key, 13
Is a display unit, 16 is a duct, 17 is a ventilation fan, 20 is an exhaust duct, 21 is a humidity sensor (gas sensor), 25 is a humidity detection circuit, 30 is a temperature sensor, and A is an object to be heated.

Claims (8)

[Claims] 1. A heating chamber in which an object to be heated is housed, heating means for supplying microwaves to the heating chamber to heat the object to be heated, a ventilation device for performing forced ventilation in the heating chamber, A gas sensor for detecting a gas such as water vapor generated from an object to be heated, and the object to be heated based on the detection by the gas sensor under the frozen condition of the object to be heated during the progress of heating by the heating means at the time of performing thawing cooking. A microwave oven comprising: a thaw control means for determining a heated capacity of an object and controlling the heating means according to the determination. 2. The microwave oven according to claim 1, wherein the thawing control means sets the entire heating time according to the heated capacity of the object to be heated. 3. The thawing control means determines the heated capacity of the object to be heated based on reading the detection value of the gas sensor at the time point when a certain time has elapsed from the start of heating by the heating means. Or the microwave oven according to 2. 4. The defrosting control means reads the detection values of the gas sensor at a plurality of different time points and determines the heated capacity of the object to be heated based on the plurality of detected values. 3. The microwave oven according to any one of 3 above. 5. The thawing control means is configured to extend the remaining heating time after the determination of the heated capacity of the object to be heated, as the detected value of the gas sensor fluctuates in the negative direction. The microwave oven according to any one of claims 1 to 4. 6. The thawing control means changes the heating output in the remaining heating time after the determination of the heated capacity of the object to be heated according to the heated capacity. Microwave oven described in. 7. A temperature sensor for detecting the temperature in the heating chamber is provided, and the defrosting control means performs correction such that the higher the temperature detected by the temperature sensor at the start of heating, the earlier the time point for determining the heated capacity. The microwave oven according to any one of claims 1 to 6, wherein: 8. A temperature sensor for detecting the temperature in the heating chamber is provided, and the thawing control means makes a correction such that the higher the temperature detected by the temperature sensor at the start of heating, the smaller the heating output by the heating means. The microwave oven according to any one of claims 1 to 7.