Heating cooker

Abstract

The present disclosure provides a heating cooker capable of sensing sufficient energy and accurately carrying out detection even using an infrared sensor having low sensitivity.　A heating cooker according to the present disclosure comprises a body, a top plate that is attached to the upper part of the body and has a cooking apparatus placed thereon, and a heating coil for generating a high-frequency magnetic field and heating the cooking apparatus, wherein: the heating cooker is provided with an infrared sensor that is provided below the top plate, the infrared sensor detecting infrared rays that are emitted from the cooking apparatus and transmitted through the top plate; and the infrared sensor is a quantum-type infrared sensor having a peak sensitivity wavelength of 2.5 μm or higher.

Description

heating cooker

[0001] The present disclosure relates to a cooking appliance.

[0002] Patent Document 1 discloses a cooking appliance having a top plate on which a cooking container is placed, a heating coil for generating an induction magnetic field to heat the cooking container, an infrared sensor that detects infrared rays radiated from the cooking container through the top plate, a control means that calculates the temperature of the cooking container from the output of the infrared sensor and controls the power supplied to the heating coil based on this calculated temperature, a filter that is provided above the infrared sensor and blocks light having a wavelength below a predetermined value, and side walls that are provided around the filter, and the infrared sensor is covered by the filter and side walls to prevent it from being affected by radiation from sunlight, etc.

[0003] Patent No. 5235678

[0004] The present disclosure provides a cooking device that is capable of detecting sufficient energy even with an infrared sensor having low sensitivity, and is capable of detecting with high accuracy.

[0005] The cooking appliance disclosed herein includes a main body, a top plate attached to the top of the main body on which a cooking utensil is placed, and a heating coil for generating a high-frequency magnetic field to heat the cooking utensil. The cooking appliance also includes an infrared sensor located below the top plate for detecting infrared rays emitted from the cooking utensil and transmitted through the top plate, the infrared sensor being a quantum infrared sensor having a peak sensitivity wavelength of 2.5 μm or greater. This specification includes the entire contents of Japanese Patent Application No. 2023-168499, filed on September 28, 2023.

[0006] According to the cooking device of the present disclosure, the infrared sensor has a peak sensitivity wavelength of 2.5 μm or more, and has a peak sensitivity in the longer wavelength range than conventional sensors, so it can detect infrared rays that have passed through the top plate from the cooking device at a high level of radiant energy. Therefore, even an infrared sensor with low sensitivity can detect sufficient energy, enabling accurate detection.

[0007] 1 is a schematic perspective view showing a cooking device according to the first embodiment. FIG. 2 is a cross-sectional view of an infrared sensor according to the first embodiment. FIG. 3 is a graph showing the relationship between the light receiving sensitivity and wavelength of an infrared sensor using InAsSb according to the first embodiment. FIG. 4 is a graph showing the relationship between the wavelength of light transmitted through a top plate, the light transmittance, and the radiant energy of an object according to the first embodiment. FIG. 5 is a graph showing the relationship between spectral radiance and wavelength. FIG. 6 is a graph showing the relationship between the wavelength and energy of the solar spectrum according to the first embodiment.

[0008] (Knowledge, etc. that formed the basis of the present disclosure) At the time the inventors arrived at the present disclosure, there were cooking appliances that used an infrared sensor made of InGaAs with peak sensitivity around 1.9 μm as the infrared sensor, and that measured the temperature of the cooking appliance in a region where the transmittance of the top plate was approximately 90% or more.

[0009] However, because the detection wavelength of conventional infrared sensors is close to visible light wavelengths, they are susceptible to external disturbances and require a limited field of view, which requires the placement of a filter to remove visible light so that visible light does not enter the infrared sensor's light receiving section, or printing on the top plate to limit the range of visible light incident thereon. Furthermore, the inventors discovered a problem in that in order to sufficiently collect infrared radiation energy, a highly sensitive device or a larger light receiving section is required, or a lens is required to collect as much energy as possible within the limited field of view, resulting in increased costs. The present disclosure provides a cooking appliance that can detect sufficient energy even with a low-sensitivity infrared sensor, allowing for accurate detection.

[0010] Hereinafter, embodiments will be described in detail with reference to the drawings. However, unnecessary detailed description may be omitted. For example, detailed description of already well-known matters or redundant description of substantially the same configuration may be omitted. Note that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0011] (Embodiment 1) Hereinafter, Embodiment 1 will be described with reference to the drawings. [1-1. Configuration] [1-1-1. Configuration of Cooker] FIG. 1 is a schematic perspective view showing a cooker according to Embodiment 1. As shown in FIG. 1, cooker 1 includes a box-shaped main body 10. A flat top plate 12 on which a cooking utensil 11, such as a pot or frying pan, is mounted is attached to the upper surface of main body 10. Top plate 12 is formed of an electrically insulating and infrared-transparent material, such as crystallized glass (also referred to as crystallized ceramic). An annular heating coil 13 is installed on the underside of top plate 12 at a predetermined distance from top plate 12. Heating coil 13 generates a high-frequency magnetic field, for example, of 20 kHz to 100 kHz. By arranging heating coil 13 in an annular shape, a substantially circular heating portion 14 is formed on top plate 12. In this embodiment, three heating coils 13 are provided, and these three heating coils 13 allow the cooking appliance 1 to simultaneously heat and cook three cooking utensils 11. Fig. 1 shows one cooking utensil 11 placed on the top plate 12. However, one, two, or four or more heating coils 13 may be provided. The top plate 12 functions as a mounting portion on which the cooking utensils 11 can be placed.

[0012] An operation panel 20 is provided on the front side of the main body 10. The operation panel 20 mainly includes an input unit 21 such as a touch panel for operating a grill 25 mounted on the main body 10, and a display 22. A user of the cooking appliance 1 operates the operation panel 20 to use the grill 25.

[0013] Additionally, a plurality of operation input units 23 and display units 24 are provided on the front side of the top plate 12 to allow the user to operate each heating coil 13. The display units 24 display the operating status of the heating coils 13, etc. The user controls, for example, the output of the heating coils 13 by operating the operation input units 23. Three operation input units 23 are provided, one for each of the three heating coils 13.

[0014] [1-1-2. Configuration of the Infrared Sensor Portion] Fig. 2 is a cross-sectional view of the infrared sensor portion. As shown in Fig. 2, an insulating plate 30 made of mica or the like is disposed between the top plate 12 and the heating coil 13. An opening 31 is formed in the insulating plate 30 at a position corresponding to approximately the center of the heating portion 14. A cylindrical light-guiding member 32 is attached to the opening 31.

[0015] The light guide member 32 includes a cylindrical main body 33 formed in a substantially cylindrical shape, and a small-diameter portion 34 having a smaller diameter than the cylindrical main body 33 is provided below the cylindrical main body 33. The inner surfaces of the cylindrical main body 33 and the small-diameter portion 34 serve as a reflective surface 35 that reflects light. The cylindrical main body 33 and the small-diameter portion 34 are formed from, for example, a resin material, and the reflective surface 35 is formed by plating the inner surface of the resin with a metal such as copper or chromium having a reflectance of 50% or more.

[0016] An infrared sensor unit 40 is disposed below the light-guiding member 32. The infrared sensor unit 40 is mounted on a predetermined wiring board and includes a box-shaped case 41. An infrared sensor 43 connected to a wiring board 42 is housed inside the case 41 of the infrared sensor unit 40. In this embodiment, the infrared sensor 43 is a quantum infrared sensor having a peak sensitivity wavelength of 2.5 μm or more. Specifically, an infrared sensor 43 using InAsSb is used as the infrared sensor 43.

[0017] 3 is a graph showing the relationship between the light receiving sensitivity and wavelength of an infrared sensor using InAsSb. As shown in FIG. 3, the infrared sensor 43 using InAsSb has a peak sensitivity wavelength at a long wavelength (2.5 μm or more), and in addition, has the characteristic of having almost no sensitivity to visible light wavelengths (400 to 780 nm). Note that a quantum infrared sensor using InSb may also be used as the infrared sensor 43.

[0018] Figure 4 is a graph showing the relationship between the wavelength of light transmitted through the top plate 12, the light transmittance, and the radiant energy of an object. As shown in Figure 4, the light transmitted through the top plate 12 made of glass has a first transmission region where light with wavelengths from 0.3 μm to 3.0 μm is transmitted. The peak light transmittance in the first transmission region is approximately 80% or more. Furthermore, the light transmitted through the top plate 12 has a second transmission region where light with wavelengths from 3.0 μm to 4.5 μm is transmitted. The peak light transmittance in the second transmission region is approximately 40% to 60%.

[0019] In this embodiment, the infrared sensor 43 uses InAsSb and has a peak sensitivity wavelength for light with a wavelength of 2.5 μm or more, so that the infrared sensor 43 of this embodiment can detect light in the second transmission region of infrared light that passes through the top plate 12.

[0020] As shown in Figure 4, when the temperature of the bottom of the cookware 11 is 70°C, the radiant energy of the infrared rays increases as the wavelength increases from 1.5 µm. Similarly, when the temperature of the bottom of the cookware 11 is 140°C, the radiant energy of the infrared rays increases as the wavelength increases from 1.3 µm. When the temperature of the bottom of the cookware 11 is 140°C, the radiant energy is greater than when the temperature is 70°C.

[0021] FIG. 5 is a graph showing the relationship between spectral radiance and wavelength. The amount of infrared radiation emitted by a completely black body is determined by the relationship between the wavelength of the light and the temperature. This is called Planck's law of radiation. As shown in FIG. 5, within the wavelength and temperature ranges covered in this disclosure, the higher the temperature, the more light is emitted. At a temperature of 1000 K, visible light is emitted, appearing to glow red, and as the temperature increases further, light of shorter wavelengths is emitted. In the wavelength range covered by this disclosure, by using wavelengths of 2.5 μm or longer, which is longer than the conventional 1.9 μm, it is possible to utilize the large amount of energy emitted from an object.

[0022] Because the infrared sensor 43 has a peak sensitivity wavelength for infrared rays with wavelengths of 2.5 μm or longer, it can detect infrared rays with high radiant energy from the bottom of the cookware 11. Therefore, as described above, even when detecting infrared rays in the second transmission region of the top plate 12, which has a lower transmittance than the first transmission region, it can detect infrared rays with high radiant energy. This makes it possible to detect low temperatures, which were previously difficult to detect because of their low energy.

[0023] A filter 44 is also disposed on the top surface of the case 41. The filter 44 is designed to cut wavelengths in this low infrared transmittance region, because the glass top plate 12 itself has a high infrared emissivity in the second transmission region (e.g., a region with a transmittance of 20% or less). This radiation from the glass can cause errors in detecting the temperature of the pot. Therefore, the filter 44 cuts wavelengths in this low infrared transmittance region. In this case, when using the filter 44 to cut the region with an infrared transmittance of 20% or less, it may cut only the long wavelength side of the second transmission region, or it may cut both the short wavelength side and the long wavelength side of the second transmission region.

[0024] [1-2. Operation] Next, the operation of the first embodiment will be described. In this embodiment, the cooking appliance 1 is operated by placing the cooking appliance 11 on the top plate 12 and operating the operation input unit 23. When the operation of the cooking appliance 1 is started, high-frequency power is supplied to the heating coil 13. When high-frequency power is supplied to the heating coil 13, the heating coil 13 generates an induction magnetic field, and the temperature of the cooking appliance 11 rises due to induction heating. When the temperature of the cooking appliance 11 rises, the cooking appliance 11 radiates infrared energy, as indicated by the Stefan-Boltzmann law.

[0025] Infrared rays are emitted from the bottom of cooking utensil 11, and pass through top plate 12 to enter light-guiding member 32. The infrared rays that enter light-guiding member 32 are reflected by reflective surface 35 inside light-guiding member 32 and sent to infrared sensor unit 40. In the infrared unit, the infrared rays pass through filter 44, which cuts out unnecessary wavelength components, and then reach infrared sensor 43.

[0026] The infrared sensor 43 has a peak sensitivity wavelength of 2.5 μm or more and is characterized by having almost no sensitivity to visible light wavelengths (400 to 780 nm), and therefore detects infrared rays in the second transmission region among the infrared rays that pass through the top plate 12. The transmittance of infrared rays in this second transmission region is smaller than that in the first transmission region, but the energy of light radiated by objects is large, so infrared rays can be detected effectively.

[0027] Furthermore, external light, i.e., sunlight, may be incident on the top plate 12, propagate through the inside of the top plate 12, and enter the infrared sensor 43 via the light-guiding member 32. Fig. 6 is a graph showing the relationship between wavelength and energy of the sunlight spectrum. As shown in Fig. 6, the detection wavelength range of the infrared sensor 43 in the first embodiment is around 3.0 μm to 4.5 μm in the second transmission range, but the energy of sunlight in this range is about ⅛ of the energy of sunlight in the range of around 1.9 μm to 2.0 μm.

[0028] Furthermore, when sunlight penetrates the top plate 12, approximately 90% of the sunlight in the wavelength range of 1.9 μm to 2.0 μm is transmitted through the top plate 12. Meanwhile, approximately 50% of the sunlight in the wavelength range of 3.0 μm to 4.5 μm, which is the second transmission range of the present disclosure, is transmitted through the top plate 12. Here, assuming that the distance between the outside of the cookware 11 and the infrared sensor unit 40 on the top plate 12 is 60 mm, for wavelengths in the 1.9 μm to 2.0 μm range, if the top plate 12 has a transmittance of 90% for every 4 mm of distance, the sunlight spectrum is attenuated by approximately 1 / 5. In contrast, for wavelengths in the 3.0 μm to 4.5 μm range, if the top plate 12 has a transmittance of 50% for every 4 mm of distance, the sunlight spectrum is attenuated by approximately 1 / 32,000.

[0029] The infrared sensor 43 of the present disclosure has a peak sensitivity wavelength of 2.5 μm or more and has the property of being almost insensitive to wavelengths of visible light (400 to 780 nm). Therefore, even if sunlight is irradiated onto the infrared sensor 43 through the top plate 12, the sunlight is irradiated onto the infrared sensor 43 in an attenuated state, and therefore is less susceptible to the influence of sunlight.

[0030] [1-3. Effects, etc.] As described above, the cooking appliance 1 of the present embodiment includes a main body 10, a top plate 12 attached to the top of the main body 10 on which the cooking appliance 11 is placed, and a heating coil 13 for generating a high-frequency magnetic field to heat the cooking appliance 11. The cooking appliance 1 includes an infrared sensor 43 attached below the top plate 12 to detect infrared rays emitted from the cooking appliance 11 and transmitted through the top plate 12. The infrared sensor 43 is a quantum infrared sensor 43 having a peak sensitivity wavelength of 2.5 μm or more. Since the infrared sensor 43 has a peak sensitivity wavelength of 2.5 μm or more and a peak sensitivity in a longer wavelength range than conventional sensors, it can detect infrared rays transmitted from the cooking appliance 11 through the top plate 12 at high radiant energy. Therefore, even a low-sensitivity infrared sensor 43 can detect sufficient energy, enabling accurate detection.

[0031] Furthermore, in the cooking appliance 1 of this embodiment, the infrared sensor 43 has a characteristic that it has peak sensitivity at wavelengths of 2.5 μm or more and has almost no sensitivity to visible light wavelengths. This eliminates the need for filters or screens that were previously required to remove visible light (disturbances). This reduces unnecessary component costs.

[0032] In the cooking appliance 1 of the present embodiment, the infrared sensor 43 is an infrared sensor made of InAsSb. This makes it possible to obtain an infrared sensor 43 that has peak sensitivity at wavelengths of 2.5 μm or more and has almost no sensitivity to visible light wavelengths, eliminating the need for a filter or screen that was previously required to remove visible light (disturbance), and reducing unnecessary component costs.

[0033] Furthermore, in the cooking appliance 1 of the present embodiment, a cylindrical light-guiding member 32 is disposed between the top plate 12 and the infrared sensor 43 to guide infrared rays transmitted through the top plate 12 to the infrared sensor 43, and a reflective surface 35 that reflects infrared rays is provided on the inner surface of the light-guiding member 32. As a result, the light-guiding member 32 guides the infrared rays transmitted through the top plate 12 to the infrared sensor 43 while reflecting them from the reflective surface 35, so that the infrared rays transmitted through the top plate 12 can be collected and sent to the infrared sensor 43, enabling accurate detection by the infrared sensor 43. In other words, since the infrared sensor 43 is not affected by visible light, a large amount of infrared rays can be collected by the reflective surface 35 of the light-guiding member 32, and as a result, a light-collecting member such as a lens is not required.

[0034] In the cooking appliance 1 of the present embodiment, the infrared sensor 43 detects infrared rays having wavelengths within a second transmittance range among those passing through the top plate 12, and a filter 44 is provided between the top plate 12 and the infrared sensor 43. The filter 44 cuts at least wavelengths within the second transmittance range of 20% or less on the long-wavelength side of the infrared rays passing through the top plate 12. Thus, the infrared sensor 43 performs detection within the second transmittance range of 2.5 μm or more, thereby enabling accurate detection because the infrared sensor 43 can detect infrared rays in a range where the infrared transmittance of the top plate 12 is low but the radiant energy is high. Furthermore, the use of the filter 44 that cuts wavelengths within a transmittance range of 20% or less reduces unnecessary infrared rays emitted by the top plate 12 itself.

[0035] (Other Embodiments) As described above, the first embodiment has been described as an example of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made. Furthermore, it is also possible to combine the components described in the first embodiment above to create new embodiments.

[0036] For example, in the first embodiment, the light-guiding member 32 is configured to include a tubular main body 33 formed in a substantially cylindrical shape and a small-diameter portion 34, and to have a metal-plated reflective surface 35 formed inside, but the present disclosure is not limited to this. Fig. 7 is a schematic cross-sectional view showing a modified example of the light-guiding member 32. The light-guiding member 32 shown in Fig. 7(a) does not include the small-diameter portion 34 and is configured with a tubular main body 33. The tubular main body 33 has a plated reflective surface 35 formed inside.

[0037] In addition, the light-guiding member 32 shown in FIG. 7( b ) has a tubular main body 33 formed of a light-reflective material such as metal. In this case, the tubular main body 33 itself serves as the reflective surface 35, so there is no need to later form the reflective surface 35 by plating or the like. In the light-guiding member 32 shown in FIG. 7( c ), a tubular member 36 made of a light-reflective material such as metal is inserted into the tubular main body 33 made of resin or the like. In this case, the tubular member serves as the reflective surface 35, so there is no need to later form the reflective surface 35 by plating or the like. In addition, the shape of the tubular main body 33 is not limited to a cylindrical shape, and may be a rectangular tubular shape or the like.

[0038] [Configurations Supported by the Above-described Embodiments] The above-described embodiments support the following configurations.

[0039] (Additional Notes) (Technology 1) A cooking appliance comprising a main body, a top plate attached to the top of the main body on which a cooking utensil is placed, and a heating coil for generating a high-frequency magnetic field to heat the cooking utensil, the cooking appliance further comprising an infrared sensor attached below the top plate for detecting infrared rays emitted from the cooking utensil and transmitted through the top plate, the infrared sensor being a quantum infrared sensor having a peak sensitivity wavelength of 2.5 μm or more. With this configuration, the infrared sensor has a peak sensitivity wavelength of 2.5 μm or more and has a peak sensitivity in a longer wavelength range than conventional sensors, so that it can detect infrared rays transmitted through the top plate from the cooking utensil at a high level of radiant energy. Therefore, even an infrared sensor with low sensitivity can detect sufficient energy, enabling accurate detection.

[0040] (Technology 2) The cooking device according to Technology 1, wherein the infrared sensor has a peak sensitivity at wavelengths of 2.5 μm or more and has almost no sensitivity to visible light wavelengths. This configuration eliminates the need for filters or screens to remove visible light (disturbances), which were previously required. This reduces unnecessary component costs.

[0041] (Technology 3) A cooking device according to Technology 1 or Technology 2, wherein the infrared sensor is an infrared sensor made of InAsSb. With this configuration, an infrared sensor can be obtained that has peak sensitivity at wavelengths of 2.5 μm or more and has almost no sensitivity to visible light wavelengths, eliminating the need for filters or blinds that were previously required to remove visible light (disturbances), and reducing unnecessary component costs.

[0042] (Technology 4) The cooking device according to any one of Technology 1 to Technology 3, wherein the infrared sensor detects infrared rays having wavelengths in a range where the transmittance of the infrared rays passing through the top plate is a second transmission region, and a filter is provided between the top plate and the infrared sensor to cut at least wavelengths in a range where the transmittance of the infrared rays passing through the top plate is 20% or less on the long wavelength side in the second transmission region. With this configuration, the infrared sensor detects infrared rays in the second transmission region where the transmittance of the infrared rays passing through the top plate is low but the infrared radiation energy is high, thereby enabling accurate detection. Furthermore, by using a filter that cuts at least wavelengths in the range where the transmittance of the infrared rays passing through the top plate is 20% or less on the long wavelength side in the second transmission region, it is possible to reduce unnecessary infrared radiation emitted by the top plate itself.

[0043] (Technology 5) A cooking device according to any one of Technology 1 to Technology 4, wherein a cylindrical light-guiding member is disposed between the top plate and the infrared sensor to guide infrared rays transmitted through the top plate to the infrared sensor, and a reflective surface is provided on the inner surface of the light-guiding member to reflect the infrared rays. According to this configuration, the light-guiding member guides the infrared rays transmitted through the top plate to the infrared sensor while reflecting them from the reflective surface, thereby concentrating the infrared rays transmitted through the top plate and sending them to the infrared sensor, enabling accurate detection by the infrared sensor. In other words, because the infrared sensor is not affected by visible light, the light-guiding member can concentrate the infrared rays, eliminating the need for a concentrating member such as a lens.

[0044] The present disclosure is suitable for use in cooking appliances that are capable of detecting sufficient energy even with an infrared sensor having low sensitivity and are capable of detecting with high accuracy.

[0045] REFERENCE SIGNS LIST 1 Cooking appliance 10 Main body 11 Cooking implement 12 Top plate 13 Heating coil 14 Heating section 20 Operation panel 21 Input section 22 Display 23 Operation input section 24 Display section 30 Insulating plate 31 Opening 32 Light guide member 33 Cylindrical main body 34 Small diameter section 35 Reflecting surface 40 Infrared sensor unit 41 Case 42 Wiring board 43 Infrared sensor 43 Quantum type infrared sensor 44 Filter

Claims

1. A cooking device comprising a main body, a top plate attached to the top of the main body on which a cooking utensil is placed, and a heating coil for generating a high-frequency magnetic field to heat the cooking utensil, and an infrared sensor disposed below the top plate for detecting infrared rays radiated from the cooking utensil and passing through the top plate, the infrared sensor being a quantum type infrared sensor having a peak sensitivity wavelength of 2.5 μm or more.

2. The cooking device according to claim 1, wherein the infrared sensor has a peak sensitivity to wavelengths of 2.5 μm or more and has almost no sensitivity to visible light wavelengths.

3. The cooking device according to claim 2, wherein the infrared sensor is an infrared sensor made of InAsSb.

4. The cooking device according to claim 1, wherein the infrared sensor detects infrared rays having wavelengths in a region where the transmittance is a second transmission region among the infrared rays that pass through the top plate, and a filter is provided between the top plate and the infrared sensor to cut at least wavelengths in a region where the transmittance on the long wavelength side in the second transmission region is 20% or less among the infrared rays that pass through the top plate.

5. A cooking device as described in any one of claims 1 to 4, wherein a cylindrical light-guiding member is disposed between the top plate and the infrared sensor for guiding infrared rays passing through the top plate to the infrared sensor, and a reflective surface for reflecting infrared rays is provided on an inner surface of the light-guiding member.

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