JPH0444962Y2 - - Google Patents

Description

[Detailed explanation of the idea] (b) Industrial application fields The present invention relates to a microwave oven.

(B) Prior Art It is already known that in a microwave oven, heating is performed continuously after cooking is completed (for example, Japanese Patent Publication No. 52-5374). The duration of the keep-warm heating is predetermined by a timer or continues until a manual stop switch is operated.

In the case of the former timer, the food cools down after the scheduled timer time has elapsed. In the case of the latter, the keep-warm heating will continue unless the stop switch is operated, but on the other hand, if the stop switch is operated even though the food has been removed from the heating chamber and there is no longer a need to keep it warm. If you forget to do this, the oven will continue to heat up indefinitely, which is not good for safety.

(c) Problems that the device is trying to solve The device is trying to provide a microwave oven that can set the keep-warm heating state for the required amount of time.

(ii) Means for solving the problems The microwave oven of the present invention comprises a heating chamber, a microwave source for supplying microwaves to the heating chamber, temperature detection means for detecting the temperature of food stored in the heating chamber based on infrared radiation emitted by the food, and control means for controlling the operation of the microwave source, the control means including a keep-warm control stage for controlling the microwave source to perform keep-warm heating after cooking is completed, and an inspection stage for inspecting whether the temperature detected by the temperature detection means has dropped significantly when the food is removed, and the keep-warm control stage is terminated based on the inspection results of the inspection stage.

(E) Effect According to the present invention, when food is taken out from the heating chamber in the heat retention control stage, the temperature detected by the temperature detection means drops significantly, and based on this result, the heat retention control is terminated.

(f) Embodiment FIG. 1 shows a mechanical diagram of a microwave oven according to an embodiment of the present invention. Microwaves output from a microwave generation source 1 consisting of a magnetron are supplied to a heating chamber 3 via a waveguide 2. The temperature detecting means 4 installed on the top wall of the heating chamber measures the temperature by inputting infrared rays emitted by the object to be measured, and the field of view of the incident infrared rays is directed toward the vicinity of the center of the turntable 5. Therefore, the temperature detection means 4 detects the temperature of the food 6 placed near the center of the turntable 5.

FIG. 2 shows an electric circuit diagram of the microwave oven. Control means 7 consisting of a microcomputer
When the timer cooking command is received from the keyboard 8 along with the timer time length, the microwave generator 1 and the turntable drive section 9 are energized for the input timer time length to execute cooking and heating, and at the end,
The buzzer drive unit 10 is energized for a predetermined period of time (for example, 5 seconds) to notify the end.

On the other hand, when the control means 7 receives a temperature cooking command together with the finishing temperature from the keyboard 8, the control means 7 controls the microwave generation source 1 and The turntable driving section 9 is energized to perform temperature cooking, and when the cooking is finished, a buzzer is used to notify the end of the cooking, but in this case, as a feature of this embodiment, the heat retention heating described later is performed.

FIG. 3 shows a control program stored in the control means 7 for the above-mentioned thermal insulation heating. The execution of this program is started when the above-mentioned temperature cooking is completed. At the time when the above-mentioned temperature cooking is completed, the driving of the microwave generation source 1 is stopped, but the energization of the turntable driving section 9 is continued, and the finishing temperature inputted above is still stored in the control means 7. has been done.

Now, when the above program starts running,
After waiting for a period of 3 minutes, it is checked whether the food product has been removed from the heating chamber 3 or not. This investigation is performed by determining whether or not the food temperature measured by the temperature detection means 4 at this point has significantly lowered than the finishing temperature (for example, 1/5 or less of the finishing temperature). That is, when the food is taken out from the heating chamber 3, the temperature detection means 4 detects the temperature on the turntable 5.
Since the surface temperature is sufficiently lower than the finishing temperature of the food, if the temperature value measured by the temperature detection means 4 is significantly lower than the finishing temperature, it means that the food has been removed from the heating chamber. It means that it was done. Note that food is usually placed in a container and placed on the turntable 5,
In this case, the container acts as a heat insulator between the food and the turntable, and the temperature difference between the two is significantly large.

If the food still exists in the heating chamber 3, the buzzer drive unit 10 is activated for a predetermined period of time (for example, 5 seconds) to issue a warning that the food is currently being kept warm.
This notification sound may be made intermittently, for example, in order to distinguish it from the normal notification sound at the end of heating cooking.

Next, the measured temperature value of the temperature detection means 4 is compared with the above-mentioned finishing temperature or a temperature slightly (for example, 5° C.) lower than that, and if the measured temperature value is equal to or higher than the comparison temperature,
Immediately or, if not, after performing reheating, respectively, returning to the 3-minute waiting step.
In the above-mentioned reheating, heating is started by energizing the microwave generation source 1, and when the temperature value measured by the temperature detection means 4 has recovered to the above-mentioned comparison temperature or more, the energization of the microwave generation source 1 is stopped and heating is stopped. It is something to do.

Therefore, as long as food is present in the heating chamber 3, a warning is issued by the buzzer every 3 minutes.
Moreover, it is reheated to keep it warm. When the food is eventually removed from the heating chamber 3, this is determined in the food removal investigation step described above, and the microwave oven enters an input standby state for new cooking. In other words, no matter when the food is taken out,
This means that the food is kept warm in the desired state, and the heat retention and heating automatically ends when the food is taken out.

In the above example, only the temperature cooking is performed, and after the completion of the temperature cooking,
Although the heat retention heating sequence is provided, the heat retention heat sequence can be continued after the timer cooking is completed. In this case, the temperature of the food is measured by the temperature detection means 4 at the end of the timer cooking and stored, and this stored value is used as a comparison value when taking out the food and checking whether it is necessary to reheat the food to keep it warm. Good.

(g) Effects of the invention According to the invention, after cooking is completed, the warming operation continues as long as the food remains in the heating chamber, so that no matter when the food is taken out, it remains in the desired warm state and the food can be taken out. Then, the thermal insulation heating is automatically completed, making it easy to handle and safe.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a sectional view, FIG. 2 is an electric circuit diagram, and FIG. 3 is a program flowchart. 1...Microwave generation source, 3...Heating chamber, 4...
...Temperature detection means.

Claims (1)

[Scope of utility model registration request] A heating chamber, a microwave generation source for supplying microwaves to the heating chamber, temperature detection means for detecting the temperature of the food based on infrared rays emitted by the food stored in the heating chamber, and the microwave generation source. The control means includes a heat retention control stage in which the microwave generation source is controlled to perform heat retention after completion of cooking, and a temperature detected by the temperature detection means when the food is taken out. 1. A microwave oven comprising: an inspection step for inspecting whether the temperature has decreased significantly, and the heat retention control step is terminated based on the test result of the inspection step.