JP2678071B2 - High frequency heating equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a high-frequency heating device that automates cooking such as thawing and warming of food.

2. Description of the Related Art A conventional high-frequency heating device will be described with respect to a detection means for thawing and warming automation.

A time auto and a weight sensor will be described as conventional thawing detection means.

Time Auto is a means to set a standard cooking time according to some common foods, and a weight sensor automatically detects the weight of the food when it is set, and prepares the food accordingly. It is a means to do.

Further, an absolute humidity sensor and a piezoelectric element sensor will be described as conventional warming detection means.

The absolute humidity sensor takes out a point where the water content in the food boils and the humidity suddenly changes from a decrease to an increase (for example, Japanese Patent Laid-Open No. 53-77365), and the piezoelectric element sensor is , Which takes out a polarization current as a voltage value due to a change in heat applied by boiling steam (see, for example, JP-A-62-62).
-37624).

Further, as another method for detecting boiling, there is a means using a diode for microwave detection. Just before the food is boiled, the output will contain noise containing high frequency components,
This is a mechanism to detect the noise. (For example, Japanese Patent Application Publication No. Sho 60-20878) Problems to be Solved by the Invention When Time Auto is used as a thawing detection means, heating is finished in a fixed time regardless of variations in weight of food, shape and initial state. Therefore, there is a problem that insufficient heating or excessive heating is likely to occur, and a certain defrosted finished state cannot be obtained.

When a weight sensor is used as the thawing detecting means, the thawing finish state is better than the time auto, but there is a problem that the cost is high due to its mechanism.

On the other hand, when an absolute humidity sensor is used as the warming detection means, gas or oil in food adheres to the sensor during cooking and the detection sensitivity decreases, so a heater for refresh heat treatment is required for each cooking. You have to burn off the deposits,
There was a problem that extra power and cost were generated.

Also, when a piezoelectric element sensor is used as the warming detection means, the temperature of the piezoelectric element itself rises unless the mounting structure is devised, and the output decreases due to the temperature characteristics, and the heating end time increases. .

Further, in the method using the detection diode, there is a problem that the noise signal is output only at the start of boiling of the food, and the detection is too slow for automation.

Further, since the above-mentioned detecting means can detect only defrosting or warming, there is a problem that both defrosting and warming cannot be detected unless two or more detecting means are combined.

Therefore, an object of the present invention is to provide a means for detecting thawing and warming of food with a simple configuration.

Means for Solving the Problems In order to achieve the above object, a high-frequency heating device of the present invention is a heating chamber for storing food, a radio wave radiating section for radiating an electromagnetic wave for heating the food, and a part of the electromagnetic wave. An antenna for detecting, a detection circuit for detecting an electromagnetic wave detected by the antenna, and a magnitude of the output of the detection circuit at a specific time point after the output of the detection circuit has stabilized after a certain time has elapsed from the start of heating and And a controller for controlling the radio wave radiating section by determining the heating time based on the correlation with the optimum end time of cooking.

Further, a heating chamber for storing food, a radio wave radiating unit for radiating electromagnetic waves for heating the food, an antenna for detecting a part of the electromagnetic waves, a detection circuit for detecting the electromagnetic waves detected by the antenna, and heating. After a certain time has elapsed from the start and after the output of the detection circuit has stabilized, the heating time is determined based on the correlation between the amount of change in the output of the detection circuit at a specific time point and the optimum end time of cooking. It is configured to include a controller that controls the radio wave emitting unit.

Further, a heating chamber for storing food, a radio wave radiating unit for radiating electromagnetic waves for heating the food, an antenna for detecting a part of the electromagnetic waves, a detection circuit for detecting the electromagnetic waves detected by the antenna, and heating. Maximum heating time obtained on the basis of the correlation between the magnitude of the output of the detection circuit and the optimum end time of cooking at a specific time after the output of the detection circuit has stabilized after a certain time has elapsed from the start, and Control for controlling the radio wave radiating section by determining the heating time by the earlier one of the maximum heating times obtained based on the correlation between the amount of change in the output of the detection circuit from a specific point of time and the optimum end time of cooking And a container.

Further, the amount of decrease in output is used as the amount of change in output.

The high-frequency heating device of the present invention having the above-mentioned configuration is a configuration that determines the heating time depending on the magnitude of the output of the detection circuit,
Since the magnitude of the output correlates with the heating time for cooking (warming or thawing), the end of heating can be estimated.

Further, the heating time is determined by the amount of change in the output of the detection circuit, and since the amount of change in output correlates with the heating time for cooking (warming or thawing), the end of heating can be estimated.

Furthermore, the heating time is determined by the size of the detection circuit and the amount of change in the output of the detection circuit, and the size of the output and the amount of change in the output are used for cooking (warming or thawing), respectively.
Since there is a correlation with the heating time of, the combination of these has an effect that the end of heating can be more appropriately estimated.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a structural view of a main body of a high-frequency heating device according to one embodiment of the present invention.

Radio waves radiated from the radio wave radiating unit 1 (in this case, a magnetron) try to give power to the food 3 in the heating chamber 2, but the manner in which the power enters depends on the state of the food 3. The antenna 4 (in this case, a dipole type with a diameter of 1 mm or less and a length of about 5 mm, mounted on the top plate of the heating chamber 2) detects a part of the radio wave in the heating chamber 2, so The change in power according to the state of 3 can be read. The signal detected by the antenna 4 passes through the detection circuit 5,
Enter the controller 6. The controller 6 judges the cooking finish such as thawing or boiling of the food according to the incident signal, and the magnetron 1
And controls the operation of the cooling fan 7.

FIG. 2 is a block diagram of an embodiment of the controller 6 according to the first aspect of the present invention. The output of the detection circuit 5 is amplified by the amplifier 8 and is sent to the A / D input port of the microcomputer 9. Based on the signal, thawing and boiling are discriminated, and the control signal 10 to the radio wave radiating part 1 and the cooling fan 7 The control signal 11 is sent to.

FIG. 3 shows the output change during warming cooking in the turntable type high frequency heating apparatus, but shows the output when the turntable is stopped for simplicity.

From the start of cooking to t _1, it shows that the oscillation mode (so-called operating point) of the radio wave radiation part irregularly fluctuates as a phenomenon peculiar to start-up, and the detection output fluctuates in an unstable manner. It shows that after _{1 the} output changes stably. Here, a stable time t ₂ after t ₁ (however,
The output magnitude V _{2 at} t ₂ is better the closer it is to t ₁ ) is correlated with the optimum end time of cooking.

This will be described with reference to FIG. When various foods are cooked by warming and t ₂ is kept constant and each V ₂ is obtained, the values fluctuate in the curves a and b. Therefore, conversely, if a certain V ₂ ′ is known, the optimal end time can be estimated to be t _min (V ₂ ′) or more and t _max (V ₂ ′) or less. Set t _min (V ₂ ) and t _max (V ₂ ) for each V _{2 to the} microcomputer.
If it is stored as Table1, the optimal end time according to the detection output can be estimated.

Returning to FIG. ₃ , the amount of decrease in output (| V ₂ −V ₃ |) at a certain time interval Δt from t _{2 to} t ₃ also correlates with the optimum end time of cooking. This will be described with reference to FIG. Similarly with different foods | V ₂ −V ₃ |
== | ΔV |, the value fluctuates in the curves of c and d. Therefore, conversely, if a certain | ▲ V ^′ ₂ ▼ − ▲ V ^′ ₃ ▼ | is known, the optimum end time is t ′ _min (| ▲ V ^′ ₂ ▼ − ▲ V ^′ ₃
▼ |) over ^{_{t 'max (| ▲ V'}} 2 ▼ - ▲ V '3 ▼ |) is able hereinafter estimated. In the microcomputer, t ′ for each | V ₂ −V ₃ |
_{If min} (| V ₂ −V ₃ |) and t ′ _max (| V ₂ −V ₃ |) are stored as Table ₂ , the optimal end time according to the initial change amount of the detection output can be estimated.

So read both V ₂ and | V ₂ −V ₃ | data,
By finding the maximum value of the optimum end time from Table 1 and Table 2 and ending the heating at the earliest, it is possible to achieve good automation, except for some exceptional foods (rice etc.). realizable.

Of course, the above is established by synchronizing the timing of taking the detection output with the turntable rotation period even when the turntable is rotated.

Further, if the processing is performed by a microcomputer, the above complicated algorithm can be easily realized.

Almost the same thing can be done for thawing, and appropriate heating can be realized by switching between thawing and warming with a menu.

FIG. 6 is a circuit diagram of the detection circuit 5 that detects the radio wave detected by the antenna 4. The matching resistor 12 (50Ω in this case), the detection diode 13 (for example, a Schottky barrier diode), the resistors 14 and 15, and the bypass capacitor 16 detect the radio wave as the voltage V _s .

FIG. 7 is a diagram in which the detection circuit 5 is configured by a microstrip line.

Copper foil patterns 18, 19, 20, and 21 are etched on a dielectric substrate 17 having a certain dielectric constant ε _r . The copper foil part 18 has a characteristic impedance of 50Ω, and the part 19 is ground. By configuring the detection circuit 5 on the microstrip line, it is easy to optimally set the length of the line in accordance with the frequency band to be detected, and the detection accuracy is improved because etching is performed.

As described above, according to the present invention, after the controller has stabilized the output of the detection circuit for a certain period of time from the start of heating, the output of the detection circuit at a specific time and the amount of decrease in output are Since the heating time can be determined at an early stage by the combination, it is possible to realize the automation of cooking such as thawing because it has a simple configuration.

In particular, since the variation is detected based on the amount of change, variations in power supply and variations in design can be absorbed, so that highly reliable and always good automation can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram of the main body of a high-frequency heating apparatus according to an embodiment of the present invention, FIG. 2 is a block diagram of an embodiment of the controller, and FIG. 3 is a characteristic diagram of detection output when the rotary dish is stopped, FIG. 4 is a characteristic diagram showing the correlation between the initial detection output and the optimum end time, and FIG.
FIG. 6 is a characteristic diagram showing the correlation between the change amount of the initial output and the optimum end time, FIG. 6 is a circuit diagram of the detection circuit, and FIG. 7 is a configuration diagram on the microstrip line of the detection circuit. 1 ... Radio wave radiating part, 2 ... Heating room, 4 ... Antenna, 5
...... Detection circuit, 6 ... Controller, 8 ... Amplifier, 9 ... Microcomputer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-58-126772 (JP, A) JP-A-59-176655 (JP, A) JP-A-63-75423 (JP, A) JP-A-1- 248490 (JP, A) Actual opening 59-170393 (JP, U) Actual opening 60-118891 (JP, U)

Claims (4)

(57) [Claims] 1. A heating chamber for storing foods, a radio wave radiating section for radiating electromagnetic waves for heating the foods, an antenna for detecting a part of the electromagnetic waves, and a detection circuit for detecting the electromagnetic waves detected by the antennas. The heating time is determined based on the correlation between the magnitude of the output of the detection circuit and the optimum end time of cooking at a specific time after a certain time has elapsed from the start of heating and the output of the detection circuit has stabilized. And a controller for controlling the radio wave radiating section. 2. A heating chamber for storing food, a radio wave radiating section for radiating electromagnetic waves for heating the food, an antenna for detecting a part of the electromagnetic waves, and a detection circuit for detecting the electromagnetic waves detected by the antenna. And, after a certain time has elapsed from the start of heating and the output of the detection circuit has stabilized, the heating time is determined based on the correlation between the amount of change in the output of the detection circuit at a specific time and the optimum end time of cooking. And a high-frequency heating device having a controller for controlling the radio wave radiating part. 3. A heating chamber for storing foods, a radio wave radiating section for radiating electromagnetic waves for heating the foods, an antenna for detecting a part of the electromagnetic waves, and a detection circuit for detecting the electromagnetic waves detected by the antennas. And the maximum heating time obtained based on the correlation between the magnitude of the output of the detection circuit and the optimum end time of cooking at a specific time after the output of the detection circuit has stabilized after a certain time has elapsed from the start of heating And, the radio wave radiating section is determined by determining the heating time by the earlier one of the maximum heating times obtained based on the correlation between the amount of change in the output of the detection circuit from the specific time point and the optimum end time of cooking. A high-frequency heating device having a controller for controlling. 4. The high-frequency heating device according to claim 2, wherein the output decrease amount is used as the output change amount.