JP5506406B2 - Induction heating cooker - Google Patents

Description

  The present invention relates to an induction heating cooker, and more particularly, to a temperature measurement method for an object to be heated that is induction-heated.

  In the temperature measurement by the infrared sensor in the induction heating cooker, the infrared rays radiated from the heated object installed on the top plate are detected by the infrared sensor installed under the top plate. Since only infrared light from the object to be heated passes through the top plate and reaches the infrared sensor, detecting only a signal in a wavelength range where the light transmittance of the top plate is high improves S / N and improves temperature measurement accuracy. Will improve.

JP 2005-216501 A Japanese Patent No. 3975864

  However, since there is no wavelength region where the top plate transmittance is 100%, even if only the wavelength region where the top plate transmittance is high is detected, not only the infrared rays of the heated object that has passed through the top plate, but the top plate Infrared rays emitted by itself are included. Therefore, there exists a subject that S / N falls and temperature measurement accuracy falls.

  An object of the present invention is to provide an induction heating cooker that can accurately measure the temperature of an object to be heated while eliminating the influence of infrared rays emitted from the top plate.

In order to achieve the above object, an induction heating cooker according to the present invention includes a top plate for supporting an object to be heated,
A coil for induction heating of an object to be heated;
A first infrared sensor and a second infrared sensor for receiving infrared rays emitted from an object to be heated and transmitted through the top plate, and infrared rays emitted from the top plate itself;
A first wavelength selection filter that is installed between the top plate and the first infrared sensor and selectively transmits infrared rays in the first wavelength range;
A second wavelength selection filter that is installed between the top plate and the second infrared sensor and selectively transmits infrared rays in a second wavelength range different from the first wavelength range;
A difference processing circuit for outputting a difference between the output of the first infrared sensor and the output of the second infrared sensor;
Based on the output of the second infrared sensor, the top plate infrared amount calculation means for calculating the amount of infrared rays emitted from the top plate itself,
From the output of the difference processing circuit, subtracting the infrared amount calculated by the top plate infrared amount calculating means, and calculating the infrared amount radiated from the heated object itself, a top plate infrared subtracting means,
Temperature calculating means for calculating the temperature of the object to be heated based on the amount of infrared light calculated by the top plate infrared subtracting means.

Moreover, the induction heating cooker according to the present invention includes a top plate for supporting an object to be heated,
A coil for induction heating of an object to be heated;
A first infrared sensor and a second infrared sensor for receiving infrared rays emitted from an object to be heated and transmitted through the top plate, and infrared rays emitted from the top plate itself;
A first wavelength selection filter that is installed between the top plate and the first infrared sensor and selectively transmits infrared rays in the first wavelength range;
A second wavelength selection filter that is installed between the top plate and the second infrared sensor and selectively transmits infrared rays in a second wavelength range different from the first wavelength range;
A difference processing circuit for outputting a difference between the output of the first infrared sensor and the output of the second infrared sensor;
Based on the output of the difference processing circuit, a top plate infrared ray amount calculating means for calculating the infrared ray amount radiated from the top plate itself,
Subtracting the amount of infrared rays calculated by the top plate infrared ray amount calculation means from the output of the first infrared sensor, and calculating the amount of infrared rays emitted from the object to be heated itself;
Temperature calculating means for calculating the temperature of the object to be heated based on the amount of infrared light calculated by the top plate infrared subtracting means.

Moreover, the induction heating cooker according to the present invention includes a top plate for supporting an object to be heated,
A coil for induction heating of an object to be heated;
A first infrared sensor and a second infrared sensor for receiving infrared rays emitted from an object to be heated and transmitted through the top plate, and infrared rays emitted from the top plate itself;
A first wavelength selection filter that is installed between the top plate and the first infrared sensor and selectively transmits infrared rays in the first wavelength range;
Disposed between the top plate and the second infrared sensor, unlike the first wavelength region, the selectively transmits infrared second wavelength band which does not include the wavelength band of infrared rays emitted from the heated object 2 A wavelength selective filter;
Based on the output of the second infrared sensor, the top plate infrared amount calculation means for calculating the amount of infrared rays emitted from the top plate itself,
Subtracting the amount of infrared rays calculated by the top plate infrared ray amount calculation means from the output of the first infrared sensor, and calculating the amount of infrared rays emitted from the object to be heated itself;
Temperature calculating means for calculating the temperature of the object to be heated based on the amount of infrared light calculated by the top plate infrared subtracting means.

  According to the present invention, the temperature of an object to be heated can be measured with high accuracy by separately calculating the amount of infrared rays emitted from the top plate itself using two infrared sensors having different measurement wavelength ranges.

It is a block diagram which shows Embodiment 1 of this invention. It is a graph which shows an example of the spectral transmittance characteristic of a top plate. The example which installed the condensing lens in front of the infrared sensor is shown. The example which installed the condensing lens which has a wavelength selection function is shown. It is explanatory drawing which shows the path | route of infrared rays. It is a block diagram which shows Embodiment 2 of this invention. It is explanatory drawing which shows the other example of the combination of a wavelength selection filter. It is a block diagram which shows Embodiment 3 of this invention. It is explanatory drawing which shows the further another example of the combination of a wavelength selection filter.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram showing Embodiment 1 of the present invention. The induction heating cooker includes a top plate 2, a coil 3, infrared sensors 4 and 5, wavelength selection filters 41 and 51, a difference processing circuit 7, a top plate infrared amount calculation means 8, and a top plate infrared subtraction means. 9 and temperature calculation means 10.

  The top plate 2 is a plate-like member for supporting the object to be heated 1 such as a pan, and is a material that can transmit the magnetic field from the coil 3 and can transmit infrared rays emitted from the object to be heated 1, for example, Crystallized glass is formed.

  The coil 3 is connected to an inverter circuit (not shown), and has a function of generating a high-frequency magnetic field when a high-frequency current is supplied from the inverter circuit, whereby the object to be heated 1 is induction-heated.

  The infrared sensors 4 and 5 are composed of thermal infrared sensors such as pyroelectric elements and thermopiles, quantum infrared sensors such as photodiodes, and the like, and have a function of outputting electrical signals in accordance with received infrared energy. It arrange | positions so that both the infrared rays radiated | emitted from the to-be-heated material 1 and permeate | transmitted the top plate 2 and the infrared rays radiated | emitted from the top plate 2 itself may be received. A preamplifier (not shown) is connected to the outputs of the infrared sensors 4 and 5.

  The wavelength selection filters 41 and 51 are optical elements having a function of selectively transmitting light in a specific wavelength range and not transmitting light outside this wavelength range, and transmit only light having a wavelength longer than a certain wavelength. A long-pass filter, a short-pass filter that transmits only light having a wavelength shorter than a certain wavelength, a band-pass filter that transmits only light in a specific range, or a combination thereof can be used.

  The wavelength selection filter 41 is installed between the top plate 2 and the infrared sensor 4 and has a function of selectively transmitting infrared light in the first wavelength range. The wavelength selection filter 51 is installed between the top plate 2 and the infrared sensor 5 and has a function of selectively transmitting infrared light in a second wavelength range different from the first wavelength range. The first wavelength range of the wavelength selection filter 41 and the second wavelength range of the wavelength selection filter 51 will be described later.

  The infrared sensors 4 and 5 and the wavelength selection filters 41 and 51 are accommodated in a cylindrical housing 6. Inside the housing 6, a separation wall 61 is provided for separating infrared rays that reach the infrared sensor 4 and infrared rays that reach the infrared sensor 5. The housing 6 and the separation wall 61 are formed of a material that reflects or absorbs infrared rays, and has a function of blocking disturbance light and stray light.

  The housing 6 is preferably located near the center of the coil 3 or divided between the coils, and disposed in the gap between them, so that even if the placement position of the object to be heated 1 varies, a small object to be heated having a diameter of about 120 mm Even when the (small pan) is placed, accurate temperature measurement can be ensured without the heated object 1 being removed from the detection range of the infrared sensor 4. The opening end of the housing 6 is preferably in contact with the back surface of the top plate 2, thereby suppressing disturbance light and stray light from entering.

  The difference processing circuit 7 is configured by a differential amplifier or the like, and outputs a difference between the output of the infrared sensor 4 and the output of the infrared sensor 5.

  The top plate infrared ray amount calculation means 8 is composed of an amplifier or the like, and calculates the infrared ray amount radiated from the top plate 2 itself based on the output of the infrared sensor 5. The amplification factor is set according to the emissivity ε of the top plate 2 according to the thermal radiation theory.

  The top board infrared subtracting means 9 is constituted by a differential amplifier or the like, and subtracts the infrared quantity calculated by the top board infrared quantity calculating means 8 from the output of the difference processing circuit 7 and is emitted from the object to be heated 1 itself. The amount of infrared rays to be calculated is calculated.

  The temperature calculation means 10 is composed of an A / D converter, a microcomputer, and the like, and calculates the temperature of the heated object 1 based on the amount of infrared rays of the heated object 1 calculated by the top panel infrared subtracting means 9.

  FIG. 2 is a graph showing an example of the spectral transmittance characteristics of the top 2. When the top plate 2 is formed of crystallized glass, the transmittance is about 90% which is almost flat at a wavelength of about 0.5 μm to about 2.6 μm, and drops from about 2.6 μm to about 2.9 μm. It shows a transmittance of 5%, rises from there again, shows a transmittance distribution having a peak of about 60% around 3.5 μm, and shows a nearly zero transmittance on the long wavelength side from around 4.5 μm.

  In contrast to the spectral transmittance characteristics of the top plate 2, the wavelength selection filter 41 has a wavelength range including a wavelength range where the transmittance of the top plate 2 is high, that is, a wavelength range where a large amount of infrared rays from the heated object 1 are transmitted. It is set to transmit the light. Further, the characteristics of the wavelength selection filter 51 are set so that the transmittance of the top plate 2 is 0, or a wavelength range in which the top plate 2 can be regarded as 0, that is, a wavelength range in which infrared rays from the object to be heated 1 do not pass. Therefore, if the difference between the transmission wavelength range of the wavelength selection filter 41 and the transmission wavelength range of the wavelength selection filter 51 is taken, only the wavelength range where the transmittance of the top plate 2 is high remains.

  In the graph of FIG. 2, for example, the region A (wavelength from 3.0 μm to the long wavelength side) is set to the wavelength region that the wavelength selection filter 41 transmits, while the region B (wavelength from 4.5 μm to the long wavelength side) is set to the wavelength. When the selection filter 51 is set to a wavelength range that is transmitted, the region A and the region B satisfy the above conditions. When the difference between the wavelength ranges of the region A and the region B is taken, the top plate 2 has a high transmittance C (wavelength 3.0 μm to wavelength 4.5 μm), and the region B has a top plate transmittance of 0. This corresponds to a wavelength range that can be considered.

  The wavelength selection filters 41 and 51 may be long pass filters or band pass filters having the same cutoff wavelength on the long wavelength side. In the case of a band pass filter, it is more preferable in that the difference between the region A and the region B can be extracted with higher accuracy.

  Although FIG. 1 shows an example in which the wavelength selection filter 41 is installed separately from the infrared sensor 4, the wavelength selection effect may be imparted by directly depositing or bonding the wavelength selection filter 41 to the infrared sensor 4. Similarly, the wavelength selection filter 51 may be provided with a wavelength selection effect by directly depositing or adhering to the infrared sensor 5.

  High-temperature substances such as the coil 3 also exist around the infrared sensors 4 and 5, and when these infrared rays are directly incident on the infrared sensor or are reflected by the top plate and become incident light, disturbance light is generated. Therefore, in order to shield such disturbance light, it is preferable to install the housing 6 in the space between the infrared sensors 4 and 5 and the top plate 2. The housing 6 may prevent an increase in temperature of the housing 6 itself by adopting an air cooling mechanism from the periphery, a water cooling mechanism, a heat insulating structure with a double structure, and the like.

  FIG. 3 shows an example in which a condenser lens is installed in front of the infrared sensor. The condenser lens 42 is installed between the top plate 2 and the infrared sensor 4, and the condenser lens 52 is installed between the top plate 2 and the infrared sensor 5, thereby efficiently collecting infrared rays from a wider field of view. It becomes possible to do.

  Further, the condensing lenses 42 and 52 so that all the light passing through the wavelength selection filter 41 reaches the light receiving window of the infrared sensor 4 and all the light passing through the wavelength selection filter 51 reaches the light receiving window of the infrared sensor 5. The crosstalk is eliminated and the separation wall 61 can be omitted. In this case, the wavelength selection filters 41 and 51 may be arranged on either the incident side or the emission side of the condenser lenses 42 and 52.

  FIG. 4 shows an example in which a condenser lens having a wavelength selection function is installed. By directly depositing or adhering an optical element having a wavelength selection characteristic equivalent to that of the wavelength selection filters 41 and 51 on the condenser lenses 42 and 52, the same function as that of the wavelength selection filters 41 and 51 is obtained. Can be granted. In this case, all the light passing through the condenser lens 42 reaches the light receiving window of the infrared sensor 4 and all the light passing through the condenser lens 52 reaches the light receiving window of the infrared sensor 5. By designing 52, crosstalk is eliminated and the separation wall 61 can be omitted.

  Next, the temperature measurement operation will be described. FIG. 5 is an explanatory diagram showing an infrared path. When the object to be heated 1 and the top plate 2 are induction-heated by energization of the coil 3, they emit infrared rays corresponding to the temperature and emissivity of each member. The heated object infrared ray 901 emitted from the article to be heated 1 and transmitted through the top plate 2 and the top plate infrared ray 902 emitted from the top plate 2 itself reach the infrared sensors 4 and 5. In addition, the infrared light generated from the coil 2 on the lower surface of the top plate 2 is reflected by the top plate 2 and reaches the infrared sensor, and the external light generated from the coil 3 is directly or other than the top plate. There is an external infrared ray 913 that reflects and reaches the infrared sensor.

  Among these infrared rays, the reflected outside light infrared ray 912 and the outside light infrared ray 913 are blocked by the housing 6 and do not enter the infrared sensors 4 and 5. On the other hand, only the heated object infrared ray 901 and the top plate infrared ray 902 pass through the wavelength selection filters 41 and 51 and enter the infrared sensors 4 and 5.

  First, consider a path through the wavelength selection filter 51. Since the wavelength selection filter 51 selects and transmits only infrared rays having a wavelength range where the transmittance of the top plate can be regarded as 0 or 0, the infrared ray 901 to be heated does not pass through the infrared sensor 5, and only the top plate infrared ray 902 is transmitted through the infrared sensor 5. Detected. In other words, infrared rays existing in the wavelength range of region B in the graph of FIG.

  Next, consider a path through the wavelength selection filter 41. Since the transmission wavelength range of the wavelength selection filter 41 includes a wavelength range having a high top plate transmittance, both the infrared rays 901 to be heated and the top plate infrared 902 are detected by the infrared sensor 4. In other words, infrared rays existing in the wavelength range of region A in the graph of FIG.

  Next, the difference processing circuit 7 shown in FIG. 1 outputs the difference between the output of the infrared sensor 4 and the output of the infrared sensor 5. Since this difference corresponds to the output from the region where the transmittance of the top plate included in the wavelength selection filter 41 is high (corresponding to region C in FIG. 2), the object to be heated infrared ray 901 is often included. The top plate infrared 902 also remains a little.

  The output of the infrared sensor 5 is sent to the top plate infrared amount calculation means 8. Since the emissivity of the top plate 2 is known according to the material, the top plate temperature can be obtained from the amount of infrared rays of the top plate infrared 902 detected by the infrared sensor 5. Therefore, a black body radiation spectrum corresponding to the top plate temperature is obtained, and from this spectrum, a wavelength region having a high top plate transmittance corresponding to the difference between the wavelength selective filter 51 and the wavelength selective filter 41 (corresponding to region C in FIG. 2). The amount of the top infrared ray included in is calculated.

  The heated object infrared ray amount and the top plate infrared ray amount included in the region C obtained by the difference processing circuit 7 and the top plate infrared ray amount contained in the region C obtained by the top plate infrared ray calculating means 8 are the top plate infrared ray amount subtracting means. 9 is sent. By subtracting the amount of infrared from the top plate infrared calculation means 8 from the amount of infrared from the infrared difference processing circuit 7, only the amount of infrared from the object to be heated 1 can be calculated.

  The output of the top infrared ray subtracting means 9 is sent to the temperature calculating means 10 to calculate the temperature of the article 1 to be heated.

  Thus, in this embodiment, it is possible to measure the temperature of the object to be heated 1 by using only the infrared sensors 4 and 5 without installing a contact temperature sensor such as a thermistor. Moreover, the accuracy of temperature measurement can be improved by excluding the amount corresponding to the infrared rays radiated from the top plate 2 from the measured value.

Embodiment 2. FIG.
FIG. 6 is a block diagram showing Embodiment 2 of the present invention. The present embodiment has substantially the same configuration as that of the first embodiment, but the arrangement of the top panel infrared ray amount calculation means 8 is different.

  In the present embodiment, the top panel infrared ray amount calculation means 8 is constituted by an amplifier or the like, and calculates the infrared ray amount radiated from the top plate 2 itself based on the output of the difference processing circuit 7. The amplification factor is set according to the emissivity ε of the top plate 2 according to the thermal radiation theory.

  The top plate infrared subtracting means 9 is constituted by a differential amplifier or the like, and subtracts the infrared amount calculated by the top plate infrared amount calculating means 8 from the output of the infrared sensor 4, and is emitted from the object to be heated 1 itself. Calculate the amount of infrared rays.

  FIG. 7 is an explanatory diagram illustrating another example of the combination of the wavelength selection filters 41 and 51. The spectral transmittance characteristics (solid line) of the top plate 2 are the same as those in FIG. 2, but in this embodiment, the wavelength selection filter 41 has a wavelength range where the transmittance of the top plate 2 is high, that is, from the object to be heated 1. It is set so as to transmit light in a wavelength range including a wavelength range in which a large amount of infrared light is transmitted. In addition to the wavelength range of the wavelength selection filter 41, the wavelength selection filter 51 has a characteristic in which the transmittance of the top plate 2 is 0 or a wavelength range in which it can be regarded as 0, that is, a wavelength range in which infrared rays from the object to be heated 1 do not transmit. It is set to transmit the light. Therefore, if the difference between the transmission wavelength range of the wavelength selection filter 41 and the transmission wavelength range of the wavelength selection filter 51 is taken, only the wavelength range where the transmittance of the top plate 2 is low remains.

  In the graph of FIG. 7, for example, the region A (wavelength from 2.8 μm to the short wavelength side) is set to the wavelength region that the wavelength selection filter 41 transmits, while the region B (wavelength from 3.0 μm to the short wavelength side) is set to the wavelength. When the selection filter 51 is set to a wavelength range that is transmitted, the region A and the region B satisfy the above conditions. When the difference between the wavelength ranges of the region B and the region A is taken, the top plate 2 has a low transmittance C (wavelength 2.8 μm to wavelength 3.0 μm), and the top of the region C has a top plate transmittance of 0. This corresponds to a wavelength range that can be considered.

  The wavelength selection filters 41 and 51 may be short-pass filters or band-pass filters having the same cut-off wavelength on the short wavelength side. In the case of a band pass filter, it is more preferable in that the difference between the region A and the region B can be extracted with higher accuracy.

  In such a configuration, the transmission wavelength range of the wavelength selection filter 41 includes a wavelength range having a high top plate transmittance, so that both the heated object infrared ray 901 and the top plate infrared ray 902 are detected by the infrared sensor 4. In other words, infrared rays existing in the wavelength range of the region A in the graph of FIG.

  On the other hand, in addition to the transmission wavelength range of the wavelength selection filter 41, the wavelength selection filter 51 transmits infrared rays in a wavelength range where the transmittance of the top plate can be regarded as 0 or 0. In other words, infrared rays existing in the wavelength range of region B in the graph of FIG.

  Next, the difference processing circuit 7 shown in FIG. 6 outputs the difference between the output of the infrared sensor 4 and the output of the infrared sensor 5. Since this difference corresponds to an output from a region where the transmittance of the top plate included in the wavelength selection filter 51 is low (corresponding to region C in FIG. 6), a large amount of top infrared rays 902 are included.

  Next, the top plate infrared ray amount calculation means 8 shown in FIG. 6 calculates the infrared ray amount radiated from the top plate 2 itself based on the output of the difference processing circuit 7.

  Next, the top plate infrared subtracting means 9 shown in FIG. 6 subtracts the top plate infrared ray amount calculated by the top plate infrared ray amount calculating means 8 from the output of the infrared sensor 4, and is radiated from the heated object 1 itself. The amount of infrared rays to be calculated is calculated.

  Next, the temperature calculation means 10 shown in FIG. 6 calculates the temperature of the heated object 1 based on the amount of infrared rays of the heated object 1 calculated by the top panel infrared subtracting means 9.

  Thus, in this embodiment, it is possible to measure the temperature of the object to be heated 1 by using only the infrared sensors 4 and 5 without installing a contact temperature sensor such as a thermistor. Moreover, the accuracy of temperature measurement can be improved by excluding the amount corresponding to the infrared rays radiated from the top plate 2 from the measured value.

Embodiment 3 FIG.
FIG. 8 is a block diagram showing Embodiment 3 of the present invention. The present embodiment has substantially the same configuration as that of the first embodiment, but the difference processing circuit 7 is omitted.

  FIG. 9 is an explanatory diagram showing still another example of the combination of the wavelength selection filters 41 and 51. The spectral transmittance characteristics (solid line) of the top plate 2 are the same as those in FIG. 2, but in this embodiment, the wavelength selection filter 41 has a wavelength range where the transmittance of the top plate 2 is high, that is, from the object to be heated 1. It is set so as to transmit light in a wavelength range including a wavelength range in which a large amount of infrared light is transmitted. Further, the characteristics of the wavelength selection filter 51 are set so that the transmittance of the top plate 2 is 0, or a wavelength range in which the top plate 2 can be regarded as 0, that is, a wavelength range in which infrared rays from the object to be heated 1 do not pass.

  In the graph of FIG. 9, for example, the region A (wavelength 2.8 μm to wavelength 4.5 μm) is set as the wavelength region that the wavelength selection filter 41 transmits, while the region B (wavelength 5.5 μm to wavelength 6.5 μm). Is set to a wavelength region that the wavelength selection filter 51 transmits. These wavelength selection filters 41 and 51 are bandpass filters.

  In such a configuration, the transmission wavelength range of the wavelength selection filter 41 includes a wavelength range having a high top plate transmittance, so that both the heated object infrared ray 901 and the top plate infrared ray 902 are detected by the infrared sensor 4. In other words, infrared rays existing in the wavelength range of region A in the graph of FIG.

  On the other hand, since the wavelength selection filter 51 selects and transmits only infrared rays having a wavelength range in which the transmittance of the top plate can be regarded as 0 or 0, the infrared ray 901 to be heated does not transmit, and the infrared sensor 5 does not transmit the infrared rays 902 on the top plate. Only detected. In other words, infrared rays existing in the wavelength range of region B in the graph of FIG.

  Next, the top plate infrared ray amount calculation means 8 shown in FIG. 8 calculates the infrared ray amount radiated from the top plate 2 itself based on the output of the infrared sensor 5.

  Next, the top plate infrared subtracting means 9 shown in FIG. 8 subtracts the top plate infrared ray amount calculated by the top plate infrared ray amount calculating means 8 from the output of the infrared sensor 4 and is emitted from the heated object 1 itself. The amount of infrared rays to be calculated is calculated.

  Next, the temperature calculation means 10 shown in FIG. 8 calculates the temperature of the heated object 1 based on the amount of infrared rays of the heated object 1 calculated by the top panel infrared subtracting means 9.

  In the present embodiment, as compared with the first and second embodiments, it is not necessary to take a difference for calculating a region where the top plate transmittance is high or a region of 0, so the difference processing circuit 7 is not necessary. Furthermore, it is difficult to be affected by the influence of individual variations in the transmission regions of the wavelength selection filters 41 and 51, and there is a possibility that the temperature of the top plate or the object to be heated can be calculated more accurately than in the first and second embodiments.

  Thus, in this embodiment, it is possible to measure the temperature of the object to be heated 1 by using only the infrared sensors 4 and 5 without installing a contact temperature sensor such as a thermistor. Moreover, the accuracy of temperature measurement can be improved by excluding the amount corresponding to the infrared rays radiated from the top plate 2 from the measured value.

1 Heated object, 2 Top plate, 3 Coil, 4, 5 Infrared sensor,
41, 51 wavelength selection filter, 6 housing, 61 separation wall,
7 difference processing circuit, 8 top plate infrared amount calculation means, 9, top plate infrared subtraction means,
10 Temperature calculation means.

Claims (8)

A top plate for supporting an object to be heated;
A coil for induction heating of an object to be heated;
A first infrared sensor and a second infrared sensor for receiving infrared rays emitted from an object to be heated and transmitted through the top plate, and infrared rays emitted from the top plate itself;
A first wavelength selection filter that is installed between the top plate and the first infrared sensor and selectively transmits infrared rays in the first wavelength range;
A second wavelength selection filter that is installed between the top plate and the second infrared sensor and selectively transmits infrared rays in a second wavelength range different from the first wavelength range;
A difference processing circuit for outputting a difference between the output of the first infrared sensor and the output of the second infrared sensor;
Based on the output of the second infrared sensor, the top plate infrared amount calculation means for calculating the amount of infrared rays emitted from the top plate itself,
From the output of the difference processing circuit, subtracting the infrared amount calculated by the top plate infrared amount calculating means, and calculating the infrared amount radiated from the heated object itself, a top plate infrared subtracting means,
An induction heating cooker comprising: a temperature calculation means for calculating the temperature of an object to be heated based on the amount of infrared light calculated by the top board infrared subtraction means. The top plate is made of a material having spectral transmittance characteristics including a high transmittance wavelength region and a low transmittance wavelength region,
The first wavelength region has both a high transmittance wavelength region and a low transmittance wavelength region,
The induction heating cooker according to claim 1, wherein the second wavelength region lacks a part of the high transmittance wavelength region as compared with the first wavelength region. A top plate for supporting an object to be heated;
A coil for induction heating of an object to be heated;
A first infrared sensor and a second infrared sensor for receiving infrared rays emitted from an object to be heated and transmitted through the top plate, and infrared rays emitted from the top plate itself;
A first wavelength selection filter that is installed between the top plate and the first infrared sensor and selectively transmits infrared rays in the first wavelength range;
A second wavelength selection filter that is installed between the top plate and the second infrared sensor and selectively transmits infrared rays in a second wavelength range different from the first wavelength range;
A difference processing circuit for outputting a difference between the output of the first infrared sensor and the output of the second infrared sensor;
Based on the output of the difference processing circuit, a top plate infrared ray amount calculating means for calculating the infrared ray amount radiated from the top plate itself,
Subtracting the amount of infrared rays calculated by the top plate infrared ray amount calculation means from the output of the first infrared sensor, and calculating the amount of infrared rays emitted from the object to be heated itself;
An induction heating cooker comprising: a temperature calculation means for calculating the temperature of an object to be heated based on the amount of infrared light calculated by the top board infrared subtraction means. The top plate is made of a material having spectral transmittance characteristics including a high transmittance wavelength region and a low transmittance wavelength region,
The second wavelength region has both a high transmittance wavelength region and a low transmittance wavelength region,
The induction heating cooker according to claim 3 , wherein the first wavelength region lacks a part of the low transmittance wavelength region as compared with the second wavelength region. A top plate for supporting an object to be heated;
A coil for induction heating of an object to be heated;
A first infrared sensor and a second infrared sensor for receiving infrared rays emitted from an object to be heated and transmitted through the top plate, and infrared rays emitted from the top plate itself;
A first wavelength selection filter that is installed between the top plate and the first infrared sensor and selectively transmits infrared rays in the first wavelength range;
Disposed between the top plate and the second infrared sensor, unlike the first wavelength region, the selectively transmits infrared second wavelength band which does not include the wavelength band of infrared rays emitted from the heated object 2 A wavelength selective filter;
Based on the output of the second infrared sensor, the top plate infrared amount calculation means for calculating the amount of infrared rays emitted from the top plate itself,
Subtracting the amount of infrared rays calculated by the top plate infrared ray amount calculation means from the output of the first infrared sensor, and calculating the amount of infrared rays emitted from the object to be heated itself;
An induction heating cooker comprising: a temperature calculation means for calculating the temperature of an object to be heated based on the amount of infrared light calculated by the top board infrared subtraction means. The top plate is made of a material having spectral transmittance characteristics including a high transmittance wavelength region and a low transmittance wavelength region,
The first wavelength region has a high transmittance wavelength region,
The induction heating cooker according to claim 5, wherein the second wavelength region has a low transmittance wavelength region. A light blocking member for covering the periphery of the first and second wavelength selection filters and the first and second infrared sensors, and blocking external light;
6. The separation wall according to claim 1, further comprising a separation wall provided in the light shielding member and configured to separate infrared rays reaching the first infrared sensor and infrared rays reaching the second infrared sensor. Induction heating cooker. A first condenser lens installed between the top plate and the first infrared sensor;
The induction heating cooker according to claim 1, 3 or 5, further comprising a second condenser lens installed between the top plate and the second infrared sensor.