JP2002075624A - Induction heating cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction heating cooker wherein heat response is superior and accurate control is made possible. SOLUTION: A radiation temperature detecting means 25 is installed to detect a bottom face temperature of a cooking container 20 via an infrared ray transparent material 24 fitted into a top plate 21, and by the light receiving means 27 to detect light which is irradiated from a light emitting means 26 to the bottom face of the cooking container 20 via the top plate 21 and which is reflected by the bottom face of the cooking container 20, and by an output of the light receiving means 27, a radiation rate is calculated from a reflecting rate of the cooking container 20, and a heat radiation temperature of the cooking container is corrected, and accurate temperature control is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating cooker used in ordinary households.

[0002]

2. Description of the Related Art A conventional induction heating cooker is described, for example, in Japanese Patent Laid-Open No. 6-302378. This structure will be described with reference to FIG.

A top plate 2 made of a non-magnetic material is mounted on the upper surface of the main body 1. On the upper surface of the top plate 2, a cooking container 4 is placed. Cooking container 4
Is a heating coil 3 provided below the top plate 2.
Is heated by the In other words, when a high-frequency current is supplied to the heating coil 3 by the control means 7, the heating coil 3 generates a high-frequency magnetic field, and this high-frequency magnetic field links with the cooking vessel 4, and the cooking vessel 4 itself generates heat by induction heating. It is. Therefore, the food stored in the cooking container 4 is heated by the heat generated by the cooking container 4, and the cooking proceeds. At this time, the control means 7 adjusts the power supplied to the heating coil 3 based on the temperature signal detected by the temperature detection means 6 to control the temperature of the food. At this time, in the technique disclosed in this document, accurate temperature control is performed by attaching the temperature detecting means 6 to the temperature sensing plate 5. The temperature sensing plate 5 is made of a non-magnetic material, and is attached to the lower surface of the top plate 2.

[0004]

In the induction heating cooker of the above-mentioned conventional construction, the heat plate receives the amount of heat of the cooking vessel through the top pool and detects the temperature of the heat plate. And has a problem that the thermal response is low. That is, since the top plate is made of ceramic and has a low thermal conductivity, the heat transfer to the temperature-sensitive plate is delayed as described above.

[0005]

According to the present invention, there is provided a radiant temperature detecting means for detecting a radiant temperature of a bottom surface of a cooking vessel below a top plate, and an electric power supplied to a heating coil according to an output of the radiant temperature detecting means. And emissivity calculation means for detecting emissivity based on the amount of light incident on the cooking vessel reflected and incident on the cooking vessel to detect differences in emissivity due to the material and bottom shape of the cooking vessel As a result, an induction heating cooker capable of performing accurate temperature control is provided.

[0006]

According to the first aspect of the present invention, a radiation temperature detecting means for detecting a radiation temperature of a bottom surface of a cooking vessel is provided below a top plate, and a heating coil is provided in accordance with an output of the radiation temperature detecting means. Controlling the supplied electric power, and providing emissivity calculating means for radiating light to the cooking vessel and detecting the emissivity based on the amount of light reflected and incident on the cooking vessel. By detecting the difference, the induction heating cooker can perform accurate temperature control.

According to a second aspect of the present invention, the radiant temperature of the bottom surface of the cooking vessel is detected below the top plate, and the emissivity is determined by the amount of light radiated to the cooking vessel and reflected and incident on the cooking vessel. By providing a radiation temperature detecting means for detecting the difference in emissivity depending on the material and bottom shape of the cooking vessel, accurate temperature control can be performed.

According to a third aspect of the present invention, the radiation temperature detecting means is provided with a transmitting material temperature detecting means for detecting the temperature of the infrared transmitting material so as to correct the transmittance of the infrared transmitting material, thereby achieving high precision. The induction heating cooker can measure the temperature of the cooking vessel and can accurately control the temperature.

According to a fourth aspect of the present invention, the radiation temperature detecting means is provided with a waveguide for guiding the light incident through the infrared transmitting material to the radiation temperature detecting means, so that the visual field range for detecting the radiation temperature is reduced. By reducing the shape of the infrared transmitting material, the induction heating cooker can measure the temperature of the cooking vessel with high accuracy and can control the temperature accurately.

According to a fifth aspect of the present invention, the radiation temperature detecting means is provided with a heat insulating means for preventing heat from the heating coil and the top plate to reduce the influence of the surrounding heat and to measure the accurate temperature. It is an induction heating cooker that can perform accurate temperature control.

According to a sixth aspect of the present invention, the radiation temperature detecting means is provided with a magnetic field shielding means for shielding an induction magnetic field from the heating coil to prevent the influence of the induction magnetic field at the time of heating, thereby enabling accurate temperature measurement. An induction heating cooker that can measure and accurately control the temperature.

[0012]

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described. FIG. 1 is a sectional view showing the configuration of the present embodiment. The induction heating cooker according to the present embodiment is provided at a lower portion of the top plate 21, a cooking container 20 for heating and cooking the food, a top plate 21 made of a non-magnetic material on which the cooking container 20 is placed. Control means 23 for controlling the power supplied to the heating coil 22; an infrared transmitting material 24 made of a material that transmits infrared light inserted into the top plate 22; and a bottom surface of the cooking vessel 20 via the infrared transmitting material 24. Radiation temperature detecting means 25 for detecting temperature
A light emitting unit 26 that emits light toward the bottom surface of the cooking container 20 via the top plate 22; a light receiving unit 27 that detects light in which the light of the light emitting unit 26 is reflected on the bottom surface of the cooking container; The cooking container 2 is output by the output of the light receiving unit 27.
Emissivity calculating means 28 for calculating the emissivity from the reflectance of 0.

The radiation temperature detecting means 25 is constituted by an infrared element for detecting infrared rays radiated from an object to be measured. The control means 23 adjusts the magnitude of the high-frequency current supplied to the heating coil 22 or controls the power supplied to the heating coil 22 according to the temperature information of the temperature detection means 25.

The infrared transmitting material 24 is made of a material that transmits infrared light, which is fitted inside the top plate 21 so that the top surface is flat. As the infrared transmitting material, for example, silicon is used, but germanium or the like may be used. The material is not limited to a single material. As the radiation temperature detecting means 25, a sensor capable of detecting infrared rays such as a pyroelectric element or a thermopile can be used.

The operation of this embodiment will be described below.
When a power supply (not shown) is turned on and a predetermined temperature is set by an operation switch, the control unit 23 supplies electric power to the heating coil 22. When electric power is supplied to the heating coil 22, an induction magnetic field is generated from the heating coil 22, and the cooking vessel 20 on the top plate 21 is induction-heated. Due to this induction heating, the temperature of the cooking container 20 rises, and the object to be heated in the cooking container 20 is cooked. At this time, the control means 23
With the temperature information from the radiation temperature detecting means 25, the progress of cooking of the object to be heated can be grasped, and the power supplied to the heating coil 22 is adjusted according to the progress of cooking. Thus, the object to be cooked in the cooking container 20 is to be cooked. The radiation temperature detecting means 25 includes the cooking vessel 2
The temperature is detected by detecting the amount of infrared rays radiated from the bottom surface of the zero. The temperature of the cooking vessel 20 is about 30 ° C.
２３０230 ° C., and the peak wavelength at this temperature is about 10 μm to 6 μm according to Stefan-Boltzmann's law.
The transmission wavelength of the top plate 21 is about 4 μm or less, and the radiation temperature from the cooking vessel 20 is detected using the infrared transmission material 24. The infrared transmitting material 24
As described above, the top plate 21 is fitted inside the top plate 21 so that the top surface is flat. That is, the temperature sensing plate 22 is provided on the top plate 21.
Has a circular hole to fit. As the cooking container 20, a plurality of pans such as a multi-layer pan made of aluminum, iron, or stainless steel is used. The emissivity differs depending on the material and the shape of the surface of the cooking container 20, and the amount of infrared radiation radiated even at the same temperature varies, resulting in a temperature detection error.

At this time, in this embodiment, the top plate 2
A light emitting means 26 for emitting light to the bottom surface of the cooking vessel 20 through the light receiving means 1; a light receiving means 27 for detecting light reflected from the light emitting means 26 to the cooking vessel 20; The emissivity of the cooking container 20 is corrected by emissivity calculating means 28 which calculates the emissivity from the reflectance of the cooking container 20. The light emitting means 26 emits light to the bottom surface of the cooking container 20 using a near infrared region of about 4 μm or less. This light is reflected on the cooking container 20 and is incident on the light receiving means 27. This incident light amount is proportional to the reflectance of the cooking container 20. The light receiving means 27 converts the incident light into an electric signal and sends it to the emissivity calculating means 28. The emissivity calculating means 28 calculates the emissivity from the signal of the reflectance to obtain the emissivity of the cooking container 20. In this calculation, since the cooking container 20 is made of metal and the transmission of infrared rays is almost zero, the emissivity is obtained by 1-reflectance. The temperature of the cooking container 20 is obtained by correcting the temperature detected by the radiation temperature detecting means 25 based on the emissivity.

That is, the radiant temperature detecting means 25 detects the bottom surface of the cooking vessel 20 in a non-contact manner and calculates the emissivity of the cooking vessel 20 by the emissivity calculating means 28. The temperature can be accurately detected. Therefore, the heating coil 22 of the control means 23
Is also adapted to the temperature change of the cooking container 20 immediately.

As described above, according to this embodiment, the cooking container 20 for heating and cooking the food, the top plate 21 made of a non-magnetic material on which the cooking container 20 is placed, and the lower portion of the top plate 21 Control means 23 for controlling the power supplied to the heating coil 22 provided in the apparatus, an infrared transmitting material 24 fitted in the top plate 21, and detecting the temperature of the bottom surface of the cooking vessel 20 via the infrared transmitting material 24. Radiation temperature detecting means 25 and the top plate 2
A light emitting means 26 for emitting light toward the bottom surface of the cooking container 20 through the light receiving means 1; a light receiving means 27 for detecting light reflected from the light emitting means 26 on the bottom surface of the cooking container 20; Emissivity calculating means 28 for calculating the emissivity from the reflectance of the cooking vessel 20 based on the output, and the emissivity of the cooking vessel 20 is detected to correct the radiation temperature of the cooking vessel. The present invention realizes a possible induction heating cooker.

(Embodiment 2) Next, a second embodiment of the present invention will be described. FIG. 2 is a cross-sectional view illustrating the configuration of the present embodiment. In the present embodiment, a heating cooking container 20 for cooking food, a top plate 21 made of a non-magnetic material on which the cooking container 20 is placed, and a heating coil 22 provided below the top plate 21 are supplied. Control means 24 for controlling power to be applied, an infrared transmitting material 24 fitted to the top plate 21, a light emitting means 26 for emitting light toward the bottom surface of the cooking vessel 20 via the infrared transmitting material 24, Radiation temperature detecting means 2 for detecting the light reflected by the light emitting means 26 on the bottom surface of the cooking vessel 20 via the infrared transmitting material 24 and detecting the temperature of the bottom face of the cooking vessel 20
Emissivity calculating means 28 for calculating the emissivity from the reflectance of the cooking vessel 20 based on the output of the radiation temperature detecting means 25
And The emissivity calculating means 28 detects the emissivity of the cooking container 20 and corrects the radiation temperature of the cooking container 20.

The second embodiment of the present invention is different from the first embodiment in that a light emitting means 26 for emitting light toward the bottom of the cooking vessel 20 through an infrared transmitting material 24, The radiation temperature detecting means 25 detects the light reflected by the light emitting means 26 on the bottom surface of the cooking container 20 via the light source 24 and detects the temperature of the bottom surface of the cooking container 20.

The light emitting means 24 emits light of a wavelength in the far infrared region, and is emitted to the bottom surface of the cooking container 20 via the infrared transmitting material 24. This light is reflected on the bottom surface of the cooking container 20 and is incident on the radiation temperature detecting means 25. The reflectance of the cooking vessel is detected based on the amount of incident light, and is sent to the emissivity calculating means 28. The emissivity calculating means 28 calculates and calculates the emissivity of the cooking vessel 20 from the reflectance. Further, the radiation temperature detecting means 25 detects the temperature of the bottom surface of the cooking container 20. The light emitting means 24 operates intermittently to alternately detect emissivity and radiation temperature.

With the above configuration, the emissivity calculating means 28 can detect the emissivity. Even if the cooking containers 20 of different materials are placed, the temperature of the cooking containers 20 can be accurately detected. That is, the power control of the heating coil 22 by the control means 23 is more accurate.

As described above, according to the present embodiment, the light emitting means 26 for emitting light toward the bottom surface of the cooking vessel 20 via the infrared transmitting material 24 and the light emitting means 26 via the infrared transmitting material 24 A radiation temperature detecting means 25 for detecting light reflected on the bottom surface of the cooking vessel 20 and detecting a temperature of the bottom face of the cooking vessel 20, and radiating from the reflectance of the cooking vessel 20 by an output of the radiation temperature detecting means 25. The emissivity calculating means 28 for calculating the emissivity is used to detect the emissivity of the cooking containers made of different materials to detect the radiant temperature, thereby realizing an induction heating cooker capable of accurate temperature control. Things.

(Embodiment 3) Next, a third embodiment of the present invention will be described. FIG. 3 is a cross-sectional view illustrating the configuration of the present embodiment. In the present embodiment, the radiation temperature detecting means is provided with a transmitting material temperature detecting means 29 for detecting the temperature of the infrared transmitting material 24 on the lower surface of the infrared transmitting material 24. The transmitting material temperature detecting means 29 is constituted by a thermistor, and can detect the temperature of the infrared transmitting material 24.

The transmittance of the infrared transmitting material 24 is not 100% but a value lower than 100%. Although measures such as an anti-reflection film are taken to increase the transmittance, silicon has a transmittance of about 80%. That is, even if the absorption by the transmission material is considered to be 0, the temperature of the transmission material is radiated for the remaining 20%. The transmitting material temperature detecting means 29 is provided for the infrared transmitting material 2.
4, the temperature of the radiation temperature detecting means 25 is corrected.

In the present embodiment, the temperature of the infrared transmitting material 24 is detected, and the radiation temperature detection error due to the emissivity of the infrared transmitting material 24 is reduced.

As described above, according to the present embodiment, the transmission material temperature detecting means 29 for detecting the temperature of the infrared transmission material 24 is provided on the lower surface of the infrared transmission material 24, and the radiation temperature of the infrared transmission material 24 based on the emissivity is provided. As a configuration in which a detection error is reduced, an induction heating cooker capable of detecting a more accurate temperature and performing accurate temperature control is realized.

(Embodiment 4) Next, a fourth embodiment of the present invention will be described. FIG. 4 is a plan view illustrating the configuration of the present embodiment. In this embodiment, the radiation temperature detecting means 25 converts the light incident through the infrared transmitting material 24 into the radiation temperature detecting means 2.
5 is provided. Waveguide 3
Numeral 0 denotes a pipe made of metal or resin, and the inner surface is mirror-finished by gold plating or the like.

Hereinafter, the operation of this embodiment will be described.
The waveguide 30 can transfer the light receiving surface of the infrared element in the radiation temperature detecting means 25 to the tip of the waveguide 30. The infrared element has a set viewing angle, and as the distance from the object to be measured becomes longer, the viewing range becomes larger. That is, the temperature of the cooking vessel 20 can be detected within the range of the infrared transmitting material 24 by reducing the visual field range, and unnecessary things can be prevented from entering the visual field range.

That is, according to this embodiment, the infrared transmitting material 2
Since the waveguide 30 for guiding the light incident through the radiator 4 to the radiation temperature detecting means 25 is provided, and the temperature of the cooking vessel 20 can be reliably detected through the infrared transmitting material 24, the induction heating can perform accurate temperature control. A cooker can be realized.

(Embodiment 5) Next, a fifth embodiment of the present invention will be described. FIG. 5 is a plan view showing the configuration of the present embodiment. In this embodiment, the radiation temperature detecting means 25 is provided with a heat insulating means 31 for preventing heat from the heating coil 22 and the top plate 21.

The heat insulating means 31 is made of a non-magnetic vacuum heat insulating material or a highly heat-resistant plastic resin, and is arranged so as to cover the radiation temperature detecting means 25.

The operation of this embodiment will be described below. The infrared element in the radiation temperature detecting means 25 is a component that is sensitive to a change in the operating temperature and is vulnerable to this thermal fluctuation. The radiation temperature detecting means 25 is disposed at the center of the heating coil 22, and the heating coil 22 is a heat-generating component which becomes high in temperature during use of the apparatus. Therefore, during use of the apparatus, it is necessary to cool it by a cooling fan (not shown). At this time, the cooling fan is not only the heating coil 22 but also
The power element and the like built in the control means 23 are also cooled at the same time. In the present embodiment, the cooling air from the cooling fan does not affect the radiation temperature detecting means 25. That is, the heat insulating means 31 prevents temperature fluctuation due to heat of the heating coil 22 and cooling air from the cooling fan. In other words, the heat insulation means 31 can prevent temperature fluctuation of the radiation temperature detection means 25, perform more accurate temperature detection, and execute accurate temperature control.

Embodiment 6 Next, a sixth embodiment of the present invention will be described. In the present embodiment, the radiation temperature detecting means 25
Is provided with magnetic field shielding means 32 for shielding the induction magnetic field from the heating coil 22. The magnetic field shielding means 3
2 uses a shielding material such as an aluminum plate.

The operation of this embodiment will be described below. During cooking, an induction magnetic field is generated from the heating coil 22,
The cooking container 20 is heated by the induction magnetic field. The induction magnetic field is provided at the center position of the heating coil 22 and is superimposed on the temperature signal of the radiation temperature detecting means 25.
That is, an error occurs in the temperature detection of the cooking container 20. The magnetic field shielding means 32 is configured to cover the radiation temperature detecting means 25 so as to shield the induction magnetic field, and shields the induction magnetic field. Further, by grounding the magnetic field shielding means 32, the shielding effect can be enhanced. The magnetic field shielding means 3
Numeral 2 can prevent superposition on the temperature signal of the radiation temperature detecting means 25.

Therefore, according to the present embodiment, the temperature of the cooking vessel can be accurately detected even during heating in which the induction magnetic field is generated, and accurate temperature control can be executed.

[0037]

As described above, according to the present invention, accurate temperature control can be performed in the induction heating cooker.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of an induction heating cooker according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of an induction heating cooker according to a second embodiment.

FIG. 3 is a sectional view showing the configuration of an induction heating cooker according to a third embodiment of the present invention;

FIG. 4 is a sectional view showing a configuration of an induction heating cooker according to a fourth embodiment;

FIG. 5 is a cross-sectional view showing a configuration of an induction heating cooker according to a fifth embodiment.

FIG. 6 is a sectional view showing the configuration of an induction heating cooker according to a sixth embodiment;

FIG. 7 is a cross-sectional view showing a configuration of a conventional induction heating cooker.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 20 Cooking container 21 Top plate 22 Heating coil 23 Control means 24 Infrared transmitting material 25 Radiation temperature detecting means 26 Light emitting means 27 Light receiving means 28 Emissivity calculating means 29 Transmitting material temperature detecting means 30 Waveguide 31 Insulating means 32 Magnetic field blocking means

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Izumi Hirota 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 3K051 AA08 AB02 AC33 AD04 AD12 AD15 AD19 AD28 AD29 CD02 CD40 CD43

Claims (6)

[Claims] An electric power to be supplied to a cooking container for heating and cooking a cooking object, a top plate made of a non-magnetic material on which the cooking container is placed, and a heating coil provided below the top plate. Control means, an infrared transmitting material fitted to the top plate, radiant temperature detecting means for detecting the temperature of the bottom surface of the cooking vessel via the infrared transmitting material, and directing toward the bottom surface of the cooking vessel via the top plate. A light emitting means for emitting light from the light source, a light receiving means for detecting light reflected from the light emitting means on the bottom surface of the cooking vessel, and an emissivity calculation for calculating an emissivity from the reflectance of the cooking vessel based on the output of the light receiving means. Means for detecting the emissivity of the cooking vessel and correcting the radiation temperature of the cooking vessel. 2. A heating cooking container for cooking the food, a top plate made of a non-magnetic material on which the cooking container is placed, and electric power supplied to a heating coil provided below the top plate are controlled. Control means, an infrared transmitting material fitted to the top plate, a light emitting means for emitting light toward the bottom of the cooking vessel via the infrared transmitting material, and a light of the light emitting means via the infrared transmitting material. Radiation temperature detecting means for detecting light reflected on the bottom surface of the cooking vessel and detecting the temperature of the bottom face of the cooking vessel; and emissivity calculation for calculating emissivity from the reflectance of the cooking vessel based on the output of the radiation temperature detecting means. Means for detecting the emissivity of the cooking vessel and correcting the radiation temperature of the cooking vessel. 3. The induction heating cooker according to claim 1, wherein the radiation temperature detecting means includes a transmitting material temperature detecting means for detecting a temperature of the infrared transmitting material. 4. The induction heating cooker according to claim 1, wherein the radiation temperature detecting means includes a waveguide for guiding light incident through the infrared transmitting material to the radiation temperature detecting means. . 5. The induction heating cooker according to claim 1, wherein the radiation temperature detecting means includes a heat insulating means for preventing heat from the heating coil and the top plate. 6. The radiation temperature detecting means includes magnetic field shielding means for shielding an induced magnetic field from a heating coil.
The induction heating cooker according to any one of the above.