JPH11126682A - Electromagnetic cooking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely detect the temperature of the bottom of a cooking container independent of the bottom shape of the cooking container and control the temperature of the cooking container to almost the setting temperature. SOLUTION: Light of a halogen lamp 6 is radiated to the bottom 17a of a cooking container 17 through a top plate 2, the cooking container 17 is induction-heated with an induction heating coil 5, and giving and receiving of radiation energy are conducted between a filament 6b of the halogen lamp 6 and the bottom 17a of the cooking container 17. The terminal voltage of the filament 6b is detected, and current is controlled so that the resistance value of the filament 6b becomes constant to keep the temperature of the filament 6b 1000 deg.C. The temperature T2 of the bottom 17a of the cooking container 17 is found by computing from the relational expression of thermal transfer amount of 0.86 kAWi= 4.88 AFη[(T1/100)<4> -(T2/100)<4> }]+Qp. Wherein Wi is the input of the filament 6b and calculated by current × voltage, T1 is the temperature of the filament 6b and 1000 deg.C, and others are a constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic cooker for detecting a temperature of a cooking vessel on a top plate by a temperature detecting means.

[0002]

The electromagnetic cooker has an induction heating coil disposed below the top plate, and a high-frequency current is applied to the induction heating coil to cause the cooking device mounted on the top plate to cook. The container is induction-heated. In order to detect the temperature of the cooking vessel and control the temperature, conventionally, a thermistor is disposed as a temperature detecting means on the lower surface of the central portion of the top plate, and the bottom of the cooking vessel is arranged by the thermistor via the top plate. Is indirectly detected.

However, in a configuration using a conventional thermistor, if the bottom of the cooking vessel has a so-called warp that is depressed upward, the center of the bottom of the cooking vessel does not adhere to the center of the top plate. Since a gap is formed between the two, there is a problem that a significant difference occurs between the temperature detected by the thermistor and the actual temperature at the bottom of the cooking vessel.

FIGS. 14 and 15 show the relationship between the detected temperature of the thermistor and the actual temperature of the bottom of the cooking vessel. The horizontal axis represents time, and the vertical axis represents temperature. FIG. 14 shows a case where the bottom of the cooking vessel is flat, the detected temperature of the thermistor converges to the set temperature Tr, and the temperature of the bottom of the cooking vessel converges to a temperature Tb slightly higher than this. On the other hand, FIG. 15 shows a case where the bottom of the cooking vessel is warped, and the detected temperature of the thermistor similarly converges to the set temperature Tr, but the temperature of the bottom of the cooking vessel is far more than this. It converges on the high temperature Tc. In FIG. 15, according to the experiment of the inventor of the present application, when the set temperature Tr was set to 150 ° C. and no-load heating was performed, that is, empty cooking, when the thermistor detected 150 ° C., the temperature at the bottom of the cooking vessel was reduced It had reached 600 ° C.

The present invention has been made in view of the above circumstances, and an object of the present invention is to be able to reliably detect the temperature of the bottom of a cooking container regardless of the bottom shape of the cooking container and to reduce the temperature of the cooking container. An object of the present invention is to provide an electromagnetic cooker that can be controlled to a substantially set temperature.

[0006]

According to a first aspect of the present invention, there is provided an electromagnetic cooking device, wherein an induction heating coil is provided in a main body case having a top plate, and a high frequency current is supplied to the induction heating coil so that the induction heating coil is provided on the top plate. An inverter circuit for inductively heating the mounted cooking vessel; a temperature detecting means having a light emitting element for emitting light to the bottom of the cooking vessel via the top plate; and a light emitting element of the temperature detecting means. The temperature of the bottom of the cooking vessel is detected based on the radiation amount and the temperature of the cooking vessel, and control means for controlling the inverter circuit according to the detected temperature is provided.

According to such a configuration, the light emitting element of the temperature detecting means is energized and emits light to the bottom of the cooking vessel, and the cooking vessel is placed on the top plate and induction heating is performed by the induction heating coil. Then, radiant energy is exchanged between the light emitting element and the bottom of the cooking container. In this case, since the heat capacity of the cooking vessel is much larger than that of the light-emitting element, the light-emitting element is affected by the radiant energy from the bottom of the cooking vessel, and the radiation amount and temperature of the light-emitting element Changes. Therefore, by measuring the change, the radiant energy at the bottom of the cooking vessel can be determined, and the temperature at the bottom of the cooking vessel can be detected.

In this case, a filament lamp may be used as the light emitting element of the temperature control means (claim 2), and a heater may be used as the light emitting element (claim 3). According to such a configuration, it is not necessary to use a special and expensive light emitting element.

According to a fourth aspect of the present invention, the electromagnetic cooker is characterized in that the control means is configured to detect the temperature of the light emitting element by the resistance value of the light emitting element. According to such a configuration, a temperature detecting unit for directly detecting the temperature of the light emitting element is not required.

According to a fifth aspect of the present invention, the electromagnetic cooker is characterized in that the control means is configured to detect a radiation amount of the light emitting element based on an input of the light emitting element. According to such a configuration, there is no need to provide a radiation amount detecting means for directly detecting the radiation amount of the light emitting element.

According to a sixth aspect of the present invention, in the electromagnetic cooker, the control means controls the resistance value of the light emitting element to be constant, and detects the temperature at the bottom of the cooking vessel by inputting the light emitting element. However, it has features. According to such a configuration, the temperature of the light emitting element can be made constant by controlling the resistance value of the light emitting element to be constant. If the input of the light emitting element at that time is calculated, heat transfer can be performed. The temperature at the bottom of the cooking vessel can be obtained by calculation based on the relational expression of the amount.

According to a seventh aspect of the present invention, in the electromagnetic cooker, the control means controls the input of the light emitting element to be constant, and detects the temperature of the bottom of the cooking vessel from the resistance value of the light emitting element. However, it has features. According to such a configuration, by controlling the input of the light emitting element to be constant and calculating the resistance value of the light emitting element, the temperature of the light emitting element can be determined from the resistance value, and therefore, the heat transfer amount can be calculated. The temperature at the bottom of the cooking container can be obtained by calculation based on the relational expression.

An electromagnetic cooker according to an eighth aspect of the present invention is characterized in that the control means is configured to set the temperature of the light emitting element so as to be substantially equal to the maximum temperature when the cooking vessel is heated. According to such a configuration, the rate of reduction of the radiation amount (input) of the light-emitting element due to a rise in the temperature of the bottom of the cooking container increases, and the sensitivity is improved.

The electromagnetic cooker according to the ninth aspect is characterized in that the light emission band of the light emitting element is set to match the light transmission band of the top plate. According to such a configuration, the light transmittance of the top plate is improved, and the temperature detection error can be reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. First,
In FIG. 3 showing the entire appearance of the electromagnetic cooker, a top plate 2 made of heat-resistant glass is mounted on the upper opening of the main body case 1 having a rectangular shape.
Indicates a placement section 2a serving as a guide for placing a cooking container. On the front side of the upper surface of the main body case 1, an operation panel 3 having various switches and indicators is provided.
Is installed.

Further, as shown in FIG.
Is provided with a mounting table 4.
An induction heating coil 5 wound in an annular shape is supported above the top plate 2 with a predetermined gap. At the center of the upper surface of the mounting table 4, a filament lamp, for example, a several W class halogen lamp 6 as a light emitting element is supported via a support frame 7. This halogen lamp 6
As shown in FIG. 2, a filament 6b is arranged in a case 6a made of a heat insulating material in the form of an arc-shaped container having an open upper surface, and the inner surface of the case 6a has a light emissivity. Film 6c is coated on the upper surface of the case 6a, and a cover 6d made of heat-resistant glass for enclosing a gas containing halogen in the case 6a.
Is installed. The upper surface of the halogen lamp 6 is in close contact with the lower surface of the central portion of the top plate 2.

The electrical configuration will now be described with reference to FIGS. First, in FIG.
Are connected to an AC input terminal of the rectifier circuit 9, and a DC output terminal of the rectifier circuit 9 is connected to an input terminal of an inverter circuit 10 mainly composed of a semiconductor switching element, for example, an IGBT. The output terminal of the inverter circuit 10 is connected to the induction heating coil 5. The microcomputer 11, which is a control means,
The temperature of the bottom of the cooking vessel is detected by calculation based on information from a temperature detection circuit 12 serving as a temperature detection means described later, and a PWM signal is sent to the inverter circuit 10 so that the detected temperature becomes the set temperature. To give.

Next, a specific configuration of the temperature control circuit 12 will be described with reference to FIG. The DC power supply terminal 13 to which the DC power supply voltage Vd is applied is grounded via a series circuit of the filament 6b of the halogen lamp 6 and the series resistor 14. And both terminals of the filament 6b are
Input ports AD1 and A of microcomputer 11
Connected to D2. The output ports D0, D1, D2, D3,..., D7 of the microcomputer 11 are connected to the bases of NPN transistors 150, 151, 152, 153,. Then, the transistors 150 and 15
1, 152, 153,... 157, each emitter is grounded, and each collector is connected in parallel with the resistors 160, 161, 162, 16
,... 167 are connected in common with each other, and the common connection point is connected to the common connection point between the filament 6b and the series resistor.

In this case, the resistance value of the series resistor 14 is Rb
, And the parallel resistors 160, 161, 162, 163,...
Resistance of ^{67, 2 0 R (= R)} , 2 1 R (= 2R),
2 2 ^R, 2 3 ^R, have been respectively set at ...... 2 ^{7 R,} these are fixed resistance value, whereas the resistance value Ra of the filament 6b of the halogen lamp 6, the temperature of the filament 6b This is a variable resistance value that changes according to the change. Thus, the microcomputer 11 has its output port D
By selectively outputting a high-level signal from D0, D1, D2, D3... D7, the combined resistance value Rx of the series resistor 14 and the parallel resistors 160, 161, 162, 163,.
Can be changed in 256 steps.

The operation of the embodiment constructed as described above will be described with reference to FIGS. now,
The current Ia flows through the filament 6b of the halogen lamp 6, and the filament 6b emits light. The cooking vessel 17 (see FIGS. 1 and 4) is placed on the top plate 2 and is induction-heated by the induction heating coil 5. Shall be. The cooking container 17 is, as shown in FIG.
7a is provided with a depression 17b at the center thereof. Thereby, light from the halogen lamp 6 is emitted from the cooking vessel 1.
7, radiated through the top plate 2 to the bottom 17a,
Transfer of radiant energy is performed between the filament 6b and the bottom 17a.

In the present embodiment, the temperature of the bottom portion 17a of the cooking vessel 17 is obtained by calculation of the microcomputer 11. The relational expression for that will be described below. First, assuming that the input of the halogen lamp 6 is Wi, the radiation amount (radiant energy) Q of the halogen lamp 6
Is represented by the following equation. Q = 0.86 kAWi [kcal] Here, k is an emissivity peculiar to the halogen lamp 6 and is a known value (constant) obtained by an experiment.

Next, a relational expression of the heat transfer amount will be described. Since the side case 6a of the halogen lamp 6 is formed of a heat insulating material, heat transfer is performed between the upper top plate 2 and the bottom 17a of the cooking vessel 17. Now, assuming that the temperature of the filament 6b is T1, the temperature of the bottom 17a of the cooking vessel 17 is T2, and the temperature of the top plate 2 is T3.
The relational expression of the heat transfer amount is as follows.

Q = {4.88AFη [(T1 / 100) ⁴ − (T2 / 100) ⁴ ]} + {4.88 A (1−η) [(T1 / 100) ⁴ − (T3 / 100) ⁴ ]} = {4.88AFη [(T1 / 100) 4 - (T2 / 100) 4]} + Qp [kcal] ...... where, a is the cross-sectional area of the filament 6b, F is the view factor, known to be obtained by experiment value ( Constant). η is the radiation transmittance of the top plate 2,
Is a value determined by the material.

In this case, the second term (= Qp) of the equation is the amount of heat transfer from the halogen lamp 6 to the top plate 2. Since the radiation light transmittance η is high, the top plate 2 The temperature rise is small, and therefore, it is considered that the temperature of the top plate 2 is substantially constant during the induction heating of the cooking vessel 17. Therefore, Qp, which is the second term of the equation, is considered as a constant. As a result, the following relational expression is obtained from the expression. 0.86kAWi = {4.88AFη [(T1 / 100) 4 - (T2 / 100) 4]} + Qp ......

Then, the temperature T2 of the bottom portion 17a of the cooking container 17 is obtained as follows based on the relational expression of this expression. When power is supplied to the electromagnetic cooker, the microcomputer 11 outputs the output ports D0, D1, D2, D3,.
7 to selectively output a high-level signal, the series resistor 14 and the parallel resistors 160, 161, 162, 1
.. 167, the current Ia flowing through the filament 6b of the halogen lamp 6 is adjusted to control the temperature T1 of the filament 6b to approximately 1000 ° C. In this case, the temperature T of the filament 6b
The relationship between 1 and its resistance value Ra is as shown in FIG. 6. If the resistance value Ra is known, the temperature T1 is known.

Here, the microcomputer 11 operates the filament 6b at the input ports AD1 and AD2.
Of the terminal voltage Va is detected.
The current Ia flowing through the filament 6b can be calculated from the following equation. Note that the microcomputer 11 determines the resistance value Rb of the series resistor 14 and the parallel resistors 160, 161, 16
2,163, resistance ² 0 R of ...... 167 (= R), 2 1 R
^{(= 2R), 2 2 R} , 2 3 R, are stored in advance ...... ^{2 7} R, then output ports D0, D1, D2, D3, ...... D7
The combined resistance Rx is calculated based on which of the output ports outputs a high-level signal.

Ia = (Vd−Va) / Rx Further, the resistance Ra of the filament 6b can be calculated from the following equation. Ra = Va / Ia ...

Then, the microcomputer 11 adjusts the combined resistance value Rx so that the resistance value Ra becomes the resistance value Ras corresponding to 1000 ° C., as shown in FIG. 6, and performs the initial setting. As described above, at the time of the initial setting, the current 1a and the voltage Va of the filament 6b are operating at the point Pa shown in FIG. Further, in order to keep the temperature T1 of the filament 6b at approximately 1000 ° C., the input Wi of the halogen lamp 6 becomes maximum as is apparent from the equation. Therefore, in this embodiment,
When the initial setting is performed, the combined resistance value Rx is set as shown in FIG.
As shown by the point Pb, eight parallel resistors 160, 161, 1
.. 167 are set to values close to the connected state. In FIG. 8, the horizontal axis indicates 256 steps, and the vertical axis indicates the combined resistance value Rx.

On the other hand, the wavelength band (light emission band) of the light emitted from the halogen lamp 6 is as shown in FIG. 9, and the light transmittance (light transmission band) determined by the material of the top plate 2 is: As shown in FIG. 10, about 90% of the light emitted from the halogen lamp 6 is transmitted to the bottom 17 a of the cooking vessel 17.
And heat transfer relationship. In FIG. 9, the horizontal axis represents wavelength (μm) and the vertical axis represents specific radiation energy (vs. maximum energy) (%). In FIG. 10, the horizontal axis represents wavelength (μm). ) And the transmittance (%) is shown on the vertical axis.

Now, the cooking container 17 is placed on the top plate 2.
Is mounted, and the induction heating coil 5 is
When the cooking vessel 17 is induction-heated by supplying a high-frequency current to the cooking vessel 17, the temperature T2 of the bottom 17a of the cooking vessel 17 is increased.
Also rises. In this case, heat is transferred between the filament 6b of the halogen lamp 6 and the bottom 17a of the cooking vessel 17, but the heat capacity of the bottom 17a of the cooking vessel 17 is much larger than that of the filament 6b of the halogen lamp 6. As a result, the temperature T1 of the filament 6b rises under the influence of the radiation energy of the bottom 17a.

The microcomputer 11 detects the resistance value Ra of the filament 6b from the equation and the equation by sequential interruption processing, and this resistance value Ra is 1000 ° C.
The combined resistance value Rx is increased so as to have a resistance value Ras corresponding to. Specifically, the parallel resistors 160, 161, 162, 1
.. 167 are sequentially disconnected by turning off the corresponding transistor in parallel with the series resistor 14 up to that point. Accordingly, the combined resistance value Rx increases so as to sequentially shift from the point Pb in FIG. 8 in the direction of the arrow Ab, and the input Wi of the filament 6b decreases so as to sequentially shift from the point Pa in FIG. 7 in the direction of the arrow Aa. . In this way, if the resistance Ra of the filament 6b is kept constant at the resistance Ras, the temperature T1 of the filament 6b is kept at approximately 1000 ° C. Therefore, the filament 6 at that time
The input Wi of b can be calculated from the equation: Wi = Va × Ia...
Is to detect the temperature T2 of the bottom 17a of the cooking vessel 17 by calculation from the temperature T1 and the input Wi based on the equation.

When the microcomputer 11 detects the temperature T2 of the bottom portion 17a of the cooking container 17 by the above-described calculation, the microcomputer 11 sets the detected temperature T2 to the set temperature Tr.
The WM signal is output and given to the inverter circuit 10. Accordingly, the amount of induction heating of the bottom portion 17a of the cooking vessel 17 by the induction heating coil 5 is controlled, and as shown in FIG. Converges to be Tr,
On the other hand, the temperature of the bottom portion 17a of the cooking container 17 converges to a temperature Ta slightly higher than the set temperature Tr. In FIG. 11, the horizontal axis indicates time, and the vertical axis indicates temperature.

As described above, according to the present embodiment, the microcomputer 11 controls the filament 6b of the halogen lamp 6 so that the resistance value Ra of the filament 6b is constant at the resistance value Ras in order to keep the temperature T1 of the filament 6b at 1000 ° C. After the initial setting by adjusting the current Ia, the cooking vessel 17 is induction-heated by the induction heating coil 5 to transmit and receive radiant energy between the bottom 17a and the filament 6b, and the resistance value of the filament 6b The current Ia is controlled so that Ra is constant at the resistance value Ras, and the temperature T2 of the bottom portion 17a at that time is changed to the temperature T1 (= 1000
° C) and the input Wi (= Ia × Va) of the filament 6b based on a heat transfer relational expression.

Therefore, since the temperature T2 of the bottom portion 17a is detected by using the transfer of radiant energy between the filament 6b and the bottom portion 17a, what is detected by the conventional thermistor using direct heat transfer is as follows. No, bottom one
Even if there is a warp 17b in the 7a, that is, the temperature T2 of the bottom 17a can be reliably detected regardless of the form of the bottom 17a, whereby the temperature of the cooking vessel 17 can be controlled to the substantially set temperature Tr. it can.

Further, according to the present embodiment, the microcomputer 11 detects the temperature T1 of the filament 6b of the halogen lamp 6 based on the resistance Ra of the filament 6b. Therefore, the microcomputer 11 directly detects the temperature T1 of the filament 6b. No temperature detecting means is required, and the radiation amount of the filament 6b is determined by the input Wi of the filament 6b.
Therefore, the radiation amount detecting means for directly detecting the radiation amount of the filament 6b is unnecessary. Therefore, only the terminal voltage Va of the filament 6b needs to be detected. Detection is also easy.

Further, according to the present embodiment, since the ordinary halogen lamp 6 is used as the light emitting element, it is not necessary to use a special and expensive light emitting element, and the embodiment can be easily implemented. it can. And according to this embodiment,
Since the light emission band of the halogen lamp 6 is set to match the light transmission band of the top plate 2, the light transmittance of the top plate 2 is improved, and the temperature detection error can be reduced.

In the above embodiment, the microcomputer 11 controls the current Ia so that the resistance Ra of the filament 6b of the halogen lamp 6 becomes constant at the resistance Ras.
Is controlled so that the temperature T1 of the filament 6b is maintained at 1000 ° C., but as a second embodiment of the present invention,
The resistance value Ra of the filament 6b is controlled so that the temperature T1 of the filament 6b is kept constant, for example, at 300 ° C. which is substantially equal to the maximum temperature of the cooking vessel 17 (for example, 240 ° C. in the case of teppanyaki cooking). Others are the same as the first embodiment.

According to such a configuration, as shown in FIG. 12, the wavelength band of the radiated light from the halogen lamp 6 is shifted to a longer wavelength band side than the case of FIG. Although the light transmittance is reduced, the heat transfer relationship can be maintained. Therefore, when the resistance value Ra of the filament 6b is controlled to be constant, the decrease rate of the input Wi due to the temperature rise of the cooking vessel 17 increases, so that the sensitivity is improved, and the temperature controllability is further improved. .

In the first and second embodiments,
Although the microcomputer 11 controls the resistance value Ra of the filament 6b of the halogen lamp 6 to be constant, as a third embodiment of the present invention, the control is performed so that the input Wi of the filament 6b is constant. You may do so. In this case, at the time of initial setting, the current Ia
And the voltage Va operate at the point Pc in FIG. 13, but sequentially shift from the point Pc in the direction of the arrow Ac as the temperature of the cooking container 17 rises.

Thus, the microcomputer 11
Is the resistance Ra of the filament 6b from the equation
The temperature T1 of the filament 6b is calculated from the calculated resistance value Ra with reference to the characteristics shown in FIG. 6, and the temperature of the bottom portion 17a of the cooking vessel 17 is calculated based on the equation from the input Wi and the temperature T1. Is detected by calculation. Therefore, according to the third embodiment, the same effect as that of the first embodiment can be obtained.

The present invention is not limited to the embodiment described above and shown in the drawings, and the following expansions and modifications are possible. Filament 6b of halogen lamp 6
May be detected by the radiation amount detecting means. The temperature of the filament 6b of the halogen lamp 6 may be detected by temperature detecting means. A small radiation heater may be used as the light emitting element.

[0042]

As is clear from the above description, the present invention can provide the following excellent effects. According to the electromagnetic cooker according to claim 1, a temperature detecting means having a light emitting element for emitting light to the bottom of the cooking vessel via a top plate is provided, and a radiation amount and a temperature of the light emitting element of the temperature detecting means are provided. The temperature of the bottom of the cooking container is detected based on the above, so that the temperature of the bottom of the cooking container can be reliably detected irrespective of the bottom shape of the cooking container, and the temperature of the cooking container is substantially set to the set temperature. Can be controlled.

In this case, a filament lamp is used as the light emitting element of the temperature control means (claim 2), and a heater is used as the light emitting element (claim 3). It is not necessary to use a special and expensive element as the light emitting element, and the implementation is easy.

According to the electromagnetic cooker of the fourth aspect, the control means detects the temperature of the light emitting element by the resistance value of the light emitting element, so that the temperature detecting means directly detects the temperature of the light emitting element. No means is required. According to the electromagnetic cooker according to the fifth aspect, since the control means detects the radiation amount of the light emitting element by the input of the light emitting element, the radiation amount detecting means directly detects the radiation amount of the light emitting element. Is unnecessary.

According to the electromagnetic cooker of the sixth aspect, the control means controls the resistance value of the light emitting element to be constant, and detects the temperature of the bottom of the cooking vessel by the input of the light emitting element. Therefore, it is only necessary to detect the terminal voltage of the light emitting element, and the temperature can be easily detected. Claim 7
In the electromagnetic cooker described above, the control means controls the input of the light emitting element to be constant, and detects the temperature at the bottom of the cooking vessel based on the resistance value of the light emitting element. The effect of is obtained.

According to the electromagnetic cooker of the eighth aspect, the control means sets the temperature of the light emitting element so as to be substantially equal to the maximum temperature when the cooking vessel is heated. Radiation of light emitting element due to temperature rise (input)
And the sensitivity is improved. According to the electromagnetic cooker according to the ninth aspect, the light emission band of the light emitting element is matched with the light transmission band of the top plate, so that the light transmittance of the top plate is improved, and the temperature detection error is reduced. can do.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part showing a first embodiment of the present invention.

FIG. 2 is a perspective view of a halogen lamp.

FIG. 3 is an overall perspective view.

FIG. 4 is a block diagram showing an electrical configuration.

FIG. 5 is a connection diagram of a temperature detection circuit.

FIG. 6 is a characteristic diagram showing a relationship between a resistance value of a filament and a temperature.

FIG. 7 is a diagram showing a current-voltage characteristic of a filament during constant control of the resistance value of the filament.

FIG. 8 is a diagram showing a change due to switching of a combined resistance value.

FIG. 9 is an energy distribution diagram of emitted light from a filament.

FIG. 10 is a diagram showing transmittance of a top plate.

FIG. 11 is a diagram showing the relationship between the detected temperature and the actual temperature at the bottom of the cooking container.

FIG. 12 is a view corresponding to FIG. 9 showing a second embodiment of the present invention.

FIG. 13 is a diagram showing current-voltage characteristics of a filament according to a third embodiment of the present invention.

FIG. 14 is a diagram corresponding to FIG. 11 of the prior art (when the bottom of the cooking vessel is flat);

FIG. 15 is a diagram corresponding to FIG. 11 of the related art (when the bottom of the cooking container is warped).

[Description of References] In the drawings, 1 is a main body case, 2 is a top plate, 5 is an induction heating coil, 6 is a halogen lamp (light emitting element), 6
b is a filament, 10 is an inverter circuit, 11 is a microcomputer (control means), 12 is a temperature detection circuit (temperature detection means), 14 is a series resistor, 150, 151, 15
2,153, ... 157 are transistors, 160,161,16
2,163, ... 167 is a parallel resistance, 17 is a cooking vessel, 17
a indicates a bottom portion, and 17b indicates warpage.

Claims (9)

[Claims] 1. A main body case having a top plate, an induction heating coil provided in the main case, and a cooking container placed on the top plate by supplying a high-frequency current to the induction heating coil. An inverter circuit that performs induction heating; a temperature detecting unit that has a light emitting element that emits light to the bottom of the cooking container via the top plate; and a radiation amount and a temperature of the light emitting element of the temperature detecting unit. An electromagnetic cooker comprising: a control unit configured to detect a temperature of a bottom portion of the cooking vessel and control the inverter circuit according to the detected temperature. 2. The electromagnetic cooker according to claim 1, wherein a filament lamp is used as the light emitting element. 3. The electromagnetic cooker according to claim 1, wherein a heater is used as the light emitting element. 4. The electromagnetic cooker according to claim 1, wherein the control means detects a temperature of the light emitting element based on a resistance value of the light emitting element. 5. The electromagnetic cooker according to claim 1, wherein the control means detects a radiation amount of the light emitting element based on an input of the light emitting element. 6. The control device according to claim 1, wherein the control means controls the resistance value of the light emitting element to be constant, and detects the temperature of the bottom of the cooking vessel by the input of the light emitting element. Item 7. An electromagnetic cooker according to Item 1. 7. The control means for controlling the input of the light emitting element to be constant and detecting the temperature of the bottom of the cooking vessel by the resistance value of the light emitting element. Item 7. An electromagnetic cooker according to Item 1. 8. The electromagnetic cooker according to claim 1, wherein the control means is configured to set the temperature of the light emitting element so as to be substantially equal to the maximum temperature when the cooking vessel is heated. . 9. The light emitting device according to claim 1, wherein a light emitting band of the light emitting element is matched with a light transmitting band of the top plate.
The described electromagnetic cooker.