JPH04288414A - Microwave oven - Google Patents

Abstract

PURPOSE:To detect the ambient temperature by using a temperature sensor for sensing the temperature in the storage in a microwave oven that carries out high frequency heating according to the ambient temperature. CONSTITUTION:A thermistor 8 outputs the detection signal Vs that corresponds to the temperature in a storage to a controller 10. An A/D converter 12 converts the detection signal Vs from a temperature sensor 8 to temperature data. A CPU 11 compares the read-out temperature by the converter 12 and the temperature stored in a memory 14 every interval time that is set in a timer 13 in the state of the finish of cooking. At this time if the temperature difference is within a specified temperature, the read-off temperature is set as the ambient temperature.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave oven that is equipped with a temperature sensor for detecting temperature inside a refrigerator and that corrects high frequency output based on ambient temperature.

0003

[Prior Art] A microwave oven with an oven function is equipped with a temperature sensor for detecting the internal temperature, and when cooking with a heater, the output to the heater is controlled so that the temperature detected by the temperature sensor becomes the set temperature. ing.

[0004] Furthermore, when high-frequency heating is performed using a magnetron, the high-frequency output is set to be either strong or weak, and the output time is arbitrarily set. in this case,
The reason why the temperature inside the refrigerator is not detected by a temperature sensor during high-frequency heating is because the inside of the food is heated during high-frequency heating, so the temperature sensor that detects the air temperature inside the refrigerator cannot detect the temperature of the food. .

By the way, the temperature inside the refrigerator is influenced by the room temperature (ambient temperature), and when the room temperature is high, the temperature inside the refrigerator also increases accordingly. For this reason, when high-frequency heating is performed using a small output, heat from the air inside the refrigerator is applied in addition to the high-frequency heating, so that the quality of cooking may vary depending on the room temperature. In other words, in a microwave oven equipped with a defrosting function, the defrosting time varies depending on the room temperature, resulting in variations in the finished defrosting process. Furthermore, in microwave ovens equipped with a bread-baking function, the fermentation temperature of the bread dough is affected by room temperature, which sometimes results in poor quality of the bread.

As a means to solve the above-mentioned problems, a temperature sensor is provided to detect the room temperature, and the thawing time or fermentation time is corrected based on the temperature detected by the temperature sensor. That is, by shortening the thawing time or fermentation time when the room temperature is high, it is possible to avoid the influence of the room temperature and prevent variations in the finished product of the food.

[0007]

However, the configuration in which a temperature sensor for detecting the room temperature is provided has the disadvantage that the addition of the temperature sensor increases the cost and complicates the circuit configuration.

The present invention has been made in view of the above circumstances, and although its purpose is to perform high-frequency heating in accordance with the ambient temperature, it does not require a configuration for detecting the ambient temperature, which would result in an increase in cost. To provide a microwave oven which can be realized without complicating the circuit configuration.

[Configuration of the invention]

0010

[Means for Solving the Problems] The present invention provides a microwave oven that is equipped with a temperature sensor for detecting internal temperature and that corrects high-frequency output based on ambient temperature. A reading means is provided for reading every cycle, and a storage means is provided for sequentially updating and storing the temperature read by the reading means, and calculating the temperature difference between the temperature read by the reading means and the temperature stored by the storage means, and storing the temperature. The control means sets the read temperature to the ambient temperature and performs high-frequency heating when the difference is within a predetermined temperature.

[0011]

[Operation] When the cooking is completed, the reading means reads the temperature detected by the temperature sensor at predetermined intervals. The storage means sequentially updates and stores the temperature read by the reading means. At this time, the control means calculates the temperature difference between the temperature read by the reading means and the temperature stored by the storage means, and sets the read temperature as the ambient temperature when the temperature difference is within a predetermined temperature.

[0012] In this case, when the cooking is completed, the internal temperature changes to follow the ambient temperature, so the temperature read when the change in temperature detected by the temperature sensor becomes small can be regarded as the ambient temperature. .

[0013] When performing high-frequency heating, the high-frequency output is corrected based on the ambient temperature set as described above, so high-frequency heating can be performed without being affected by the ambient temperature.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In the microwave oven shown in FIG. 2 with the door 1 open, an operation panel 2 is provided with a plurality of operation switches 3, a time adjustment knob 4, and a display 5. A turntable 7 is disposed on the bottom surface of the chamber interior 6, and a thermistor 8 as a temperature sensor is disposed on the side wall.

In FIG. 1 showing the electrical configuration of the main parts, one end of the thermistor 8 is connected to a DC power supply line, and the other end is connected to an earth line via a resistor 9. A common connection point between the thermistor 8 and the resistor 9 is connected to an input terminal of the control device 10. In this case, the thermistor 8 has a negative characteristic in which the resistance value decreases as the temperature rises.
As a result, the signal level of the detection signal Vs from the thermistor 8 increases as the temperature inside the refrigerator increases.

The control device 10 includes, in addition to a CPU 11 as a reading means and a control means, an A/D converter 12, a timer 13, a memory 14 as a storage means, and the like. Here, A/
The D converter 12 is provided to receive the detection signal Vs from the thermistor 8, and this
is digitally converted and output to the CPU 11 as temperature data. The timer 13 is provided so that a temperature reading interval time is set, and each time the set interval time elapses, the timer 13 notifies the CPU 11 that the time is up.

[0017]The CPU 11 also operates an A/D converter 12.
The temperature data from the timer 13 is inputted at the notification timing of the timer 13 to read the temperature inside the refrigerator, and the read temperature is stored in the memory 14.
The information is stored while being updated sequentially. Further, the CPU 11 controls the output to the heater 15 based on the temperature detected by the thermistor 8. Further, in the cooking completion state, the CPU 11 calculates the difference between the temperature read from the thermistor 8 and the temperature stored in the memory 14, and corrects the output to the magnetron 16 based on the calculation result. It has become.

Next, the operation of the above configuration will be explained with reference to FIG. 3, which shows the operation of the control device 10. Note that FIG. 3 shows only the part related to room temperature detection in the operation of the control device 10, and the output control for the heater 15 and magnetron 16 is omitted.

When the power is turned on (step S1), the control device 10 performs room temperature reading setting (step S1).
2). In this room temperature reading setting, the control device 10 sets the temperature reading interval in the timer 13, and
The read temperature based on the detection data from the A/D converter 12 is stored in the memory 14 as a storage temperature Tb.

[0020] Next, the control device 10 determines whether or not cooking has been completed (step S3), and if cooking has not been completed, determines whether or not cooking is in progress (step S6).
). At this time, if cooking is not in progress, the control device 10:
Proceeding to step S7, it is determined whether or not the temperature reading interval in the timer 13 has ended, and if it has not ended, other processing is executed (step S12).
) Return to step S3.

When the interval time set in the timer 13 has elapsed, the control device 10 reads the temperature based on the temperature data from the A/D converter 12 and sets it as the read temperature Tc (step S8). ). Subsequently, the control device 10 reads the read temperature Tc and the stored temperature Tb.
It is determined whether the temperature difference between the
. At this time, if the temperature difference is within δT, the control device 10
The process proceeds to step S10, where the reading temperature Tc is set to room temperature, and the reading temperature Tc is set to the storage temperature Tb (step S11). Further, when the calculated value is greater than or equal to δT, the process proceeds to step S11, and the read temperature Tc is set to the stored temperature Tb. Subsequently, the control device 10
The process advances to step S12 to execute other processing, and then returns to step S3. Here, when performing thawing or fermentation by high-frequency heating in other processing, the control device 10 corrects its output according to the set room temperature.

[0022] Through the above operations, in the cooking completion state from when the power is turned on until cooking starts, the change in the internal temperature during the elapse of the temperature reading interval set in the timer 13 is the predetermined temperature (δT). If it is within the range, the internal temperature at that time is set as the room temperature. That is, if no cooking is performed for a long period of time,
Since the temperature inside the refrigerator substantially matches the ambient temperature, the temperature read by the thermistor 8 can be regarded as the room temperature.

[0023] When the heating cooking is executed, the control device 10 determines ``YES'' in step S6, proceeds to step S13, and determines whether or not the cancel key has been pressed. At this time, when the cancel key is pressed, the control device 10 executes the room temperature reading setting (step S14), clears the cooking setting (step S15), and proceeds to step S12. Also,
When the cancel key is not pressed, control device 1
0 reads the cooking temperature using the thermistor 8 (step S16) and then proceeds to step S12.

With the above-described operation, when the heater 15 performs heating cooking, the heating cooking is performed based on the temperature read by the thermistor 8.

Now, when the cooking is finished, the control device 1
0, it is determined "YES" in step S3, and the process proceeds to step S4, where room temperature reading settings are performed, and
After clearing the cooking settings (step S5), the process proceeds to step S6. At this time, since the cooking is completed, the control device 10 performs the steps from step S6 to step S7.
It is determined whether the temperature reading interval has elapsed or not, and if the temperature reading interval has not elapsed, the process proceeds to step S12.

In the cooking completion state as described above, when the temperature reading interval set in the timer 13 has elapsed, the control device 10 adjusts the temperature between the temperature Tc read by the thermistor 8 and the temperature Tb stored in the memory 14. Set the room temperature based on the difference.

Here, FIG. 4 shows changes in the internal temperature (temperature detected by the thermistor 8) when cooking is performed. That is, since the heating completion state continues for a long period of time until heating cooking is started, the temperature inside the refrigerator substantially matches the room temperature. Then, when cooking starts, the internal temperature rises rapidly and is maintained at the set temperature.

[0028] Furthermore, when the cooking is finished, the temperature inside the refrigerator begins to drop rapidly, and the degree of decline becomes more gradual as time passes. Then, after a sufficient period of time has elapsed since the end of cooking, the temperature inside the refrigerator becomes approximately equal to the room temperature. In this case, the internal temperature is read by the thermistor 8 during the period from the cooking end timing until the degree of change in the internal temperature becomes sufficiently small, and from then on until the next cooking starts, the reading temperature is will now be set as room temperature.

In short, in the case of the above embodiment, when the change in the temperature read from the thermistor 8 for detecting the internal temperature in the cooking completion state falls within a predetermined temperature range, the read temperature is set as the room temperature. This makes it possible to reliably set the room temperature based on the temperature detected by the thermistor 8. Therefore, compared to the case where a temperature sensor for detecting room temperature is provided separately, the room temperature can be detected without providing a temperature sensor for detecting room temperature, and the configuration can be simplified accordingly.

[0030]

Effects of the Invention As is clear from the above explanation, according to the microwave oven of the present invention, when the change in the temperature read in a predetermined period by the temperature sensor for detecting the internal temperature is within a predetermined temperature, Since the temperature read by the temperature sensor is set as the ambient temperature when This has an excellent effect in that it can be realized without complicating the circuit configuration.

[Brief explanation of the drawing]

[Fig. 1] A block diagram of a main part of an electric circuit showing an embodiment of the present invention.

[Figure 2] Overall perspective view

[Figure 3] Flowchart showing the operation of the CPU

[Figure 4] Diagram showing changes in internal temperature

[Explanation of symbols]

8 is a temperature sensor, 10 is a control device, 11 is a CPU (reading means, control means), and 13 is a memory (storage means).

Claims (1)

[Claims] 1. A microwave oven comprising a temperature sensor for detecting internal temperature and correcting high frequency output based on ambient temperature, the reading means reading the temperature detected by the temperature sensor at predetermined intervals in a cooking completion state. and storage means for sequentially updating and storing the temperature read by the reading means, and calculating a temperature difference between the temperature read by the reading means and the temperature stored by the storage means, and the temperature difference being within a predetermined temperature. and control means for setting the read temperature to the ambient temperature and performing high-frequency heating.