JP2010113882A - Heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating cooker which precisely detects the temperature of an article to be heated to perform an appropriate heating operation. <P>SOLUTION: This heating cooker includes: an infrared temperature detector 18 that is disposed above a top plate 12 on which the article 14 to be heated is placed and detects the temperature of the article 14 to be heated based on the dose of infrared radiation emitted from the article 14 to be heated; and a controller 22 that controls a driver 17 based on the temperature of the article 14 to be heated, detected by the infrared temperature detector 18, to control the heating operation of a heating portion 16, wherein the infrared temperature detector 18 detects the temperatures of a plurality of points in a region to be detected such as the side surface of the article 14 to be heated on the top plate 12, a boundary between the article 14 to be heated and the top plate 12, and the top plate 12, determines whether the surface state of the article 14 to be heated is a mirror or non-mirror surface based on the results of the detected temperatures, and then corrects the temperature of a predetermined point among the temperatures of the plurality of points based on a preset emissivity depending on the result of determination to set corrected temperature as the temperature of the article 14 to be heated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cooking device that performs cooking using electromagnetic induction.

  In a conventional general cooking device, the temperature of an object to be heated (for example, a pan) placed on the top plate is detected, and the temperature of the object to be heated is adjusted by controlling the heating means based on the temperature. It is possible to perform reliable heating cooking such as preventing burning of the heated object and raw cooking.

  In such a heating cooker, various techniques for accurately detecting the temperature of the object to be heated have been proposed. For example, a material detecting means for detecting the material of the object to be heated and an infrared temperature detecting means for detecting the amount of infrared rays emitted from the object to be heated are provided, and the object to be heated is detected from the material of the object to be heated detected by the material detecting means. There is an induction heating cooker that calculates the emissivity of the object and estimates the temperature of the object to be heated by correcting the infrared amount of the object to be heated detected by the infrared temperature detecting means with the emissivity (for example, Patent Documents) 1, Patent Document 2).

In addition, as a cooking device employing another temperature detection method, a light emitting means, a light receiving means, and an infrared temperature detecting means are disposed under the top plate, and light is emitted from the light emitting means to the bottom surface of the object to be heated via the top plate. The reflected light reflected from the bottom of the heated object is received by the light receiving means through the top plate, and detected by the infrared temperature detecting means using the emissivity of the heated object converted from the received light amount. There is a cooking device that corrects the amount of infrared rays of the object to be heated and estimates the temperature (see, for example, Patent Document 3).
Japanese Patent No. 4120536 (page 3, page 4, FIG. 1) JP 2003-264055 A (page 4, FIG. 1) Japanese Patent Laid-Open No. 11-225881 (page 3, FIG. 1)

  In the heating cookers of Patent Document 1 and Patent Document 2, the emissivity is determined according to the material of the object to be heated, and the infrared ray amount of the object to be heated is corrected based on the emissivity to estimate the temperature of the object to be heated. Like to do. However, even if the material is the same, the amount of infrared rays emitted from the object to be heated differs depending on the surface state of the object to be heated. It cannot be detected. Specifically, when the black body infrared emissivity is 1.0, when the material of the object to be heated is, for example, mirror-finished iron, the emissivity is 0.21, but the specular state is lost due to rust. Will be 0.69. Thus, when the emissivity is different, the amount of infrared rays emitted from the heated object changes even if the temperature of the heated object is the same. Therefore, if the emissivity is uniquely determined based on the material, there is a problem that an accurate temperature cannot be detected and the heating operation of the object to be heated becomes unstable.

  Moreover, in the heating cooker of patent document 3, although the amount of infrared rays radiated | emitted from a to-be-heated object is detected through a glass top plate, a top plate is using low temperature (about 150 degrees C or less) infrared rays. Since it has a characteristic of cutting, a temperature of about 150 ° C. or lower cannot be correctly detected. In addition, on the measurement principle that the light projected from the light emitting means is reflected by the object to be heated, and the reflected light is received by the light receiving means, avoid disturbance light such as illumination other than reflected light from entering the light receiving means. Need to be configured. Therefore, the light emitting means and the light receiving means are disposed below the top plate, and light is projected from the bottom of the top plate toward the bottom (pan bottom) of the object to be heated so that the reflected light from the pan bottom is received. However, in the case of a so-called warped pan in which the bottom of the pan is recessed, the reflected light is scattered as compared with a flat pan bottom, so that the reflected light cannot be received well and the temperature cannot be detected correctly.

  This invention is made | formed in view of such a point, and it aims at obtaining the heating cooker which can detect the temperature of a to-be-heated object correctly, and can perform suitable heating operation | movement.

  The cooking device according to the present invention includes a top plate on which the object to be heated is placed, a heating unit that is provided below the top plate and heats the object to be heated, a driving unit that drives the heating unit, and a top plate. And an infrared temperature detector that detects the temperature of the object to be heated based on the amount of infrared rays emitted from the object to be heated, and a drive unit based on the temperature of the object to be heated detected by the infrared temperature detector And an infrared temperature detector that controls the side of the object to be heated placed on the top plate, the boundary between the object to be heated and the top plate, and the ceiling. Detects the temperature of multiple locations in the detection area including the plate, determines whether the surface condition of the object to be heated is specular or non-specular based on the temperature detection result, and sets the emissivity preset according to the determination result Based on the above, the temperature at a predetermined location among the temperatures at multiple locations is corrected to the temperature of the object to be heated A.

  According to the present invention, the surface condition of the object to be heated is determined to be specular or non-specular, and the temperature is converted using the emissivity according to the determination result, so the temperature of the object to be heated is accurately detected. It becomes possible to perform an appropriate heating operation.

Embodiment 1 FIG.
FIG. 1 is a perspective view schematically showing the appearance of a heating cooker according to Embodiment 1 of the present invention, and FIG. 2 is a side sectional view of FIG.
The main body 11 of the heating cooker is disposed on the upper surface of the main body 11, and is disposed on one side of the upper surface of the main body 11 and the top plate 12 made of a heat resistant material such as ceramics for placing the object to be heated 14. The operation unit 13 provided with operation switches (not shown) for setting the device on / off and the heating temperature of the object 14 to be heated placed on the top plate 12, and the device on / off and the set temperature Is displayed. Further, immediately below the top plate 12, a heating unit 16 composed of a heating coil for heating an object to be heated 14 placed on the top plate 12, and a commercial supplied from an AC power source (not shown). And a drive unit 17 that converts electric power into high-frequency power and supplies the electric power to the heating unit 16.

  The heating cooker further includes an infrared temperature detection unit 18 that includes an infrared detection unit 19 that detects the amount of infrared rays emitted from the article 14 to be heated. The infrared detection unit 19 is arranged above the top plate 12 so as to face the top surface of the top plate 12, and the infrared temperature detection unit 18 converts the infrared amount detected by the infrared detection unit 19 to a temperature by the temperature detection unit 20. It converts and outputs temperature data to the control part 22 mentioned later. In the main body 11, a contact-type temperature detection unit 21 that is disposed so as to be in thermal contact with the back surface of the top plate 12 and detects the temperature of the object to be heated 14 via the top plate 12, and a control unit 22. And. The control unit 22 controls the drive unit 17 based on the operating conditions input and set from the operation unit 13 and the detected temperatures of the infrared temperature detection unit 18 and the contact-type temperature detection unit 21, and performs the heating operation of the heating unit 16. Control.

  Next, the configuration of the infrared detection unit 19 and the arrangement on the main body 11 will be described. FIG. 3 is a diagram illustrating a configuration of a light receiving element portion of the infrared detection unit. FIG. 4 is an explanatory diagram of an arrangement position of the infrared detection unit. As shown in FIG. 3, the infrared detection unit 19 includes, for example, a plurality of light receiving elements 1 (1a to 1h) arranged in the vertical direction, and here, eight infrared detectors are arranged. Each of the light receiving elements 1 (1a to 1h) receives infrared rays emitted from the object to be heated 14. The angle of the light receiving area of each light receiving element 1 is set within 5 degrees, for example, and the object to be heated is placed on all the light receiving elements 1 as shown in FIG. It arrange | positions so that the pan bottom part from the side surface (pot skin part) of the heating thing 14 and also a top plate part can be stored in a light reception area.

  In the example of FIG. 4, the infrared rays radiated from the pot skin are received by the light receiving areas a to c by the light receiving elements 1a to 1c, and the infrared rays radiated from the bottom of the pot are received by the light receiving areas d and e by the light receiving elements 1d and 1e. It receives light and receives infrared rays emitted from the top plate portion in the light receiving areas f to h by the light receiving elements 1 f to 1 h. The correspondence relationship between each part of the object to be heated 14 and the light receiving areas a to h varies depending on the size of the object to be heated 14, but in any case, the side surface of the object to be heated 14 (naked skin part), the object to be heated 14 and The boundary part (pan bottom part) with the top plate 12 and the top plate 12 (top plate part) are accommodated in a light receiving area (detected area) so that temperature can be detected in a plurality of locations in the detected area in the vertical direction. Each light receiving element 1 is arranged. The amount of infrared rays detected by each of the light receiving elements 1 is converted into temperature by the temperature detection unit 20 using the following Stefan-Boltzmann law.

  The radiant energy M from the object is obtained by the following equation (1).

  When this is applied to the amount of infrared rays P received by the light receiving element 1, the following equation (2) is obtained.

  From the above equation (2), the following equation (3) is obtained.

By substituting a known value into the equation (3), that is, the temperature T ₀ of the light receiving element 1 itself, the emissivity ε of the object, the constant k, and the amount of infrared rays P received by the light receiving element 1, the temperature T of the object is obtained. It is done. That is, the temperature T of the object can be obtained from the infrared ray amount P if the temperature T ₀ of the light receiving element 1 itself and the emissivity ε of the object are known.

  The present invention detects the temperature at a plurality of locations in the detection area, determines whether the surface condition of the object to be heated 14 is specular or non-specular from the temperature detection result, and uses the emissivity according to the determination result. It has the characteristic in calculating the temperature of the to-be-heated material 14, and the characteristic part is demonstrated below.

First, the principle that can determine whether the surface state of the object to be heated 14 is a mirror surface or a non-mirror surface from the temperature detection results at a plurality of locations in the detection region will be described.
FIG. 5 is a diagram showing detected temperatures by the respective light receiving elements 1a to 1h when the emissivity of the object to be heated is small (corresponding to a mirror surface). FIG. 6 is a diagram illustrating detected temperatures by the respective light receiving elements 1a to 1h when the emissivity of the object to be heated is large (corresponding to a non-mirror surface).

As shown in FIG. 5, when the emissivity is small, the temperature at the bottom of the pan is detected higher than that at the pan skin or top plate. The reason for this will be described below.
Between emissivity ε and reflectance R, a relationship of ε + R = 1 is established. When the object to be heated 14 is made of stainless steel and the surface state is a mirror surface, the emissivity is as low as 0.15, and conversely, the reflectivity is as high as 0.85. Infrared rays corresponding to the heat transmitted to the top plate 12 by contact with the heated object 14 in the heated state are radiated to the bottom of the heated object 14. The infrared light is reflected by the surface of the object to be heated 14 having a high reflectance and is received by the light receiving element 1. That is, with respect to the light receiving elements 1a to 1c and 1f to 1h corresponding to the pot skin portion and the top plate portion, infrared rays radiated from the pot skin portion and the top plate portion themselves are received, but the light receiving elements corresponding to the pot bottom portion. Since 1d and 1e are also affected by the reflection of infrared rays from the top plate portion, they receive more infrared rays than the light receiving elements 1a to 1c and 1f to 1h corresponding to the pan skin portion and the top plate portion. Therefore, in the case of the to-be-heated object 14 with a small emissivity, there exists the characteristic that the detection temperature of a pan bottom part becomes high compared with a pan skin part or a top-plate part.

On the other hand, in the case of the non-specular surface heated object 14 having a high emissivity, as shown in FIG. 6, there is a characteristic that there is not much temperature difference between the pot skin part and the pot bottom part. From the above, it is possible to determine the specular / non-specular by the following formula.
(A) Element temperature indicating maximum temperature−detection temperature of light receiving element 1a ≦ threshold, non-mirror surface (b) Element temperature indicating maximum temperature−detection temperature of light receiving element 1a> threshold

  In the above equations (a) and (b), the detection temperature of the light receiving element 1a is used, but the height position of the detection area a of the light receiving element 1a is set to all the light receiving elements 1a to 1h as shown in FIG. In the detection areas a to h, the uppermost position is the position farthest from the top 12. Therefore, since the temperature of the pot skin portion of the object to be heated 14 can be always stably detected regardless of the influence of the heat from the top plate 12 and the size of the object to be heated 14, the detection temperature of the light receiving element 1a is set to the mirror surface / It is used to determine non-specular surfaces.

  In this way, the specular / non-specular is determined, and the emissivity is determined according to the determination result. Specifically, when it is determined to be a non-specular surface, the emissivity corresponding to the non-specular surface is determined, and when it is determined to be a specular surface, the emissivity corresponding to the specular surface is determined. In this example, the emissivity is 0.94 in the case of a non-mirror surface, and the emissivity is 0.21 in the case of a mirror surface. The reason will be described below.

  Table 1 is a table showing the relationship between typical materials and emissivity, and shows emissivity for each surface state of each material.

  In the case where the object to be heated 14 has a non-mirror surface, the lowest 0.94 is set as the emissivity corresponding to the non-mirror surface among the emissivities of typical non-mirror surfaces (hollows and painted products). In the case of a non-specular surface, the emissivity is large, and thus the temperature is detected lower than the actual temperature of the object 14 to be heated. For this reason, it is possible to improve the detection accuracy by assigning the lowest 0.94. On the other hand, when the object to be heated 14 is a mirror surface, the highest one of the emissivities of typical mirror surfaces (aluminum, iron (polishing), stainless steel) is the emissivity corresponding to the mirror surface. In the case of a mirror surface, since the emissivity is small, it is detected higher than the actual temperature of the object to be heated 14. For this reason, it is possible to improve detection accuracy by assigning the highest value of 0.21.

  Then, the temperature is calculated using the emissivity determined according to the specular / non-specular as described above. At this time, any one of the light receiving elements 1a to 1h is determined as a representative element, a temperature is calculated using the amount of infrared rays detected by the representative element and the determined emissivity, and the temperature is calculated as an object to be heated. The temperature is 14. Here, assuming that the light receiving element 1a is used as a representative element, the amount of infrared rays detected by the light receiving element 1a and the emissivity determined according to the specular / non-specular are substituted into the equation (3) to obtain the temperature. calculate. As the representative element, for the same reason as described above, the light receiving element 1a that can always stably detect the temperature of the pot skin portion is preferable, but is not limited thereto. For example, the light receiving elements 1a to 1c that detect the pot skin portion may be used, and the temperature may be calculated from the average value of the amount of infrared rays detected by each.

FIG. 7 is a block diagram illustrating a specific configuration of the infrared temperature detection unit and a processing unit involved in controlling the heating unit based on the temperature detection result of the infrared temperature detection unit. In FIG. 7, the same parts as those in FIG.
In addition to the light receiving element 1, the infrared detection unit 19 collects an infrared ray emitted from the detection area A, a scanning unit 31, and an output signal selected by the scanning unit 31 to a predetermined level. A first amplifying unit 32 for amplifying and a reference temperature element 33 composed of a thermistor are provided. The temperature detected by the reference temperature element 33 corresponds to the temperature T ₀ of the light receiving element 1 itself (see the above formulas (1) to (3)).

  The temperature detection unit 20 is specifically composed of a microcomputer, and a signal output unit 41 that outputs an address signal to the scanning unit 31 corresponding to each light receiving element 1 at a predetermined timing, and an amplification unit of the infrared detection unit 19 And a multiplexer unit 42 that receives an output signal from 32 and selects / switches each of the light receiving elements 1a to 1h. Further, from the A / D converter 43 that converts the output voltage from the multiplexer 42 into a digital signal, the temperature converter 44 that converts the digital signal from the A / D converter 43 into temperature data, and the temperature converter 44 A temperature calculation unit 45 that calculates the temperature of the object to be heated 14 based on each output temperature data and outputs the temperature to the control unit 22 is provided.

  Output signals (infrared rays) of the respective light receiving elements 1a to 1h are amplified and input to the A / D conversion unit 43 through the multiplexer unit 42, and the temperature conversion unit 44 receives the light receiving element 1a. The amount of infrared rays detected at ˜1h is converted into temperature data based on the above equation (3), and is output to the temperature calculation unit 45 as the detected temperature by each of the light receiving elements 1a-1h. Here, the emissivity is converted into temperature data as the temporary emissivity “1”. The mirror surface / non-mirror surface determination unit 45a of the temperature calculation unit 45 determines whether the surface state of the object to be heated 14 is a mirror surface or a non-mirror surface based on the detected temperatures of the light receiving elements 1a to 1h input from the temperature conversion unit 44. judge. The determination method here is based on the above (a) and (b). Then, the temperature calculated by the provisional emissivity “1” is corrected based on the emissivity according to the determination result, and the corrected temperature is output to the control unit 22 as the temperature of the object to be heated 14.

  Moreover, the contact-type temperature detection part 21 is a part which detects the temperature of the to-be-heated object 14 via the top plate 12, for example, is comprised with a thermistor. The output signal of the contact temperature detection unit 21 is input to the multiplexer unit 42. The output voltage from the multiplexer unit 42 is converted into a digital signal by the A / D conversion unit 43, converted into temperature data by the temperature conversion unit 44, and input to the temperature calculation unit 45.

Next, the temperature detection operation in the induction heating cooker according to the first embodiment will be described with reference to FIG. FIG. 8 is a flowchart showing the flow of temperature detection processing.
When the operation switch of the operation unit 13 is turned on, the control unit 22 drives the heating unit 16 via the drive unit 17. An eddy current flows through the object to be heated 14 by the magnetic flux generated from the heating unit 16, and the object to be heated 14 is induction-heated by the eddy current. The contact-type temperature detector 21 starts temperature detection when the operation switch is turned on, and checks whether the temperature has increased by a predetermined temperature (for example, 20 ° C.) (S1). When the object to be heated 14 is not sufficiently heated immediately after the start of heating, the temperature of the object to be heated 14 and the temperature of the infrared detection unit 19 itself (detection temperature of the reference temperature element 33) are equal to each other. The detection unit 18 cannot accurately detect the temperature of the object 14 to be heated. For this reason, after waiting for the temperature to rise by a predetermined temperature, the temperature of the object to be heated 14 is detected. In addition, although the detection temperature of the contact-type temperature detection part 21 is used for determination of step S1 here, since the accuracy here is not requested | required so much, the light receiving element 1a-1h of the infrared temperature detection part 18 is used. Among them, for example, the temperature may be used by using the maximum infrared ray amount and the provisional emissivity “1”.

  And if the temperature of the to-be-heated material 14 rises by predetermined temperature, the temperature calculation part 45 will acquire the temperature data of each light receiving element 1a-1h from the temperature conversion part 44 (S2). The temperature data in step S2 is calculated as a temporary emissivity “1”. Then, the mirror surface / non-mirror surface determination unit 45a of the temperature calculation unit 45 determines whether the difference between the maximum temperature and the detection temperature of the light receiving element 1a among the detection temperatures of the light receiving elements 1a to 1h is equal to or less than a preset threshold value. Is determined to be a non-mirror surface if it is equal to or less than the threshold value, and is determined to be a mirror surface if the threshold value is exceeded (S3).

  If it is determined to be non-specular, temperature correction is performed using an emissivity of 0.94 corresponding to the non-specular (S4). Specifically, the temperature is calculated by substituting the emissivity of 0.94 and the amount of infrared rays detected by the light receiving element 1a into the above equation (3), and this is used as the temperature of the object 14 to be heated. On the other hand, when it determines with a mirror surface, temperature correction is performed using the emissivity 0.21 corresponding to a mirror surface (S5). Specifically, similarly to the above, the temperature is calculated by substituting the emissivity 0.21 and the amount of infrared rays detected by the light receiving element 1a into the above equation (3), and this is used as the temperature of the object 14 to be heated. . And the control part 22 controls the drive part 17 based on the temperature of the to-be-heated material 14 calculated | required as mentioned above, and controls the heating operation of the heating part 16. FIG.

As described above, the first embodiment has the following effects.
As described above, the emissivity of the object to be heated 14 is not uniquely determined by the material, and varies depending on the mirror surface / non-mirror surface even if the material is the same. Therefore, by determining whether the surface state of the object to be heated 14 is a mirror surface or a non-mirror surface as in this example, and performing temperature conversion using the emissivity according to the determination result, the actual surface of the object to be heated 14 Accurate temperature detection according to the state becomes possible. As a result, cooking can be performed at an accurate temperature, and the cooking object can be cooked well.

  Moreover, since temperature detection is performed based on the amount of infrared rays radiated from the side surface of the object to be heated 14, temperature detection can be accurately performed even with a warped pan.

  Further, in the case of a temperature sensor that detects the temperature of the object to be heated 14 via the top plate 12, a delay due to the temperature rise of the top plate 12 occurs until the temperature can be detected. The temperature of the object to be heated 14 can be detected without such a delay.

  Moreover, since the exact temperature of the to-be-heated object 14 can be detected, the excessive heating by mistaking the temperature can be prevented, and the energy consumption can be reduced.

Embodiment 2. FIG.
In the first embodiment, the temperature of the object to be heated 14 is detected using the infrared temperature detector 18 in both cases where the surface state of the object to be heated 14 is mirror surface / non-mirror surface. In the case of a mirror surface, the temperature of the object to be heated 14 is detected by using a contact-type temperature detection unit 21 instead of the infrared temperature detection unit 18. Since the structure of the heating cooker of Embodiment 2 is the same as that of Embodiment 1 shown in FIG.2 and FIG.7, please refer FIG.2 and FIG.7.

  FIG. 9 is a flowchart showing a flow of temperature detection processing in the cooking device according to Embodiment 2 of the present invention. In the temperature detection process of the second embodiment, the processes from step S1 to S4 are the same as those of the first embodiment shown in FIG. And in Embodiment 2, when it determines with a mirror surface by step S3, the temperature detected by the contact-type temperature detection part 21 is made into the temperature of the to-be-heated object 14 (S11).

  When dirt adheres to the surface of the object 14 to be heated, the emissivity increases. Therefore, when the infrared temperature detector 18 performs temperature conversion with the emissivity as a fixed value as in the first embodiment, the emissivity is higher than the actual temperature. It detects low. This phenomenon is the same for both the mirror surface and the non-mirror surface, but in the case of the mirror surface, the phenomenon appears remarkably depending on the degree of contamination. If the temperature is detected to be lower than the actual temperature in this way, for example, it may be determined that the oil has not yet reached despite the fact that the ignition temperature of the oil has actually been reached. Inconvenience occurs. Therefore, in the case of a mirror surface, by setting the temperature detected by the contact-type temperature detection unit 21 as the temperature of the object to be heated 14, such inconvenience can be eliminated and safety can be improved.

  As described above, according to the second embodiment, the same effect as in the first embodiment can be obtained, and the temperature detected by the contact-type temperature detection unit 21 when the surface state of the article to be heated 14 is a mirror surface. Is set to the temperature of the object to be heated 14, so that even when the surface of the object to be heated 14 is contaminated, it is possible to perform effective heating control in terms of safety.

Embodiment 3 FIG.
In the third embodiment, the material of the object to be heated 14 is determined, and the emissivity is determined in consideration of the material determination result in addition to the above-described mirror surface / non-mirror surface determination result.

FIG. 10 is a side cross-sectional view of a heating cooker according to Embodiment 3 of the present invention. FIG. 11: is a block diagram of the process part in connection with the temperature detection in the heating cooker which concerns on Embodiment 2 of this invention. 10 and 11, the same parts as those in FIGS. 2 and 7 are denoted by the same reference numerals.
The heating cooker according to the third embodiment is obtained by newly adding a material determination unit 50 for determining the material of the article to be heated 14 to the heating cooker according to the first embodiment shown in FIG. The material determination unit 50 determines whether the material of the object to be heated 14 is iron, stainless steel, aluminum, or enamel, and outputs the material determination result to the temperature calculation unit 45 of the temperature detection unit 20. Conventionally known methods can be adopted as the material determination method. For example, the current flowing in the heating unit 16 and the input current to the cooking device are detected and determined.

  The temperature calculation unit 45 holds an emissivity table 45b indicating the relationship between the surface state and emissivity for each material, and the material determination result from the material determination unit 50 and the determination by the mirror / non-mirror surface determination unit 45a. The emissivity is determined by referring to the emissivity table 45b based on the result. The emissivity table 45b corresponds to a configuration in which the coating pot portion is omitted from Table 1 (the coating pot cannot be determined by the material determination).

FIG. 12: is a flowchart which shows the flow of the temperature detection process in the heating cooker which concerns on Embodiment 3 of this invention. In FIG. 12, the same steps as those in FIG. 8 of the first embodiment are denoted by the same reference numerals.
If the operation switch of the operation part 13 is turned ON, the control part 22 will start the drive of the heating part 16 via the drive part 17, and the material determination part 50 will perform material determination (S21). And it is checked whether the temperature of the to-be-heated material 14 rose for a predetermined temperature (for example, 20 degreeC) (S1). When the temperature of the object to be heated 14 rises by a predetermined temperature, the temperature calculation unit 45 acquires temperature data of each of the light receiving elements 1a to 1h from the temperature conversion unit 44 (S2), and the object to be heated 14 is a mirror surface or a non-mirror surface. It is determined whether or not (S3). The temperature calculation unit 45 refers to the emissivity table 45b based on the material determination result from the material determination unit 50 and the determination result of the mirror / non-mirror surface determination unit 45a to determine the emissivity (S22). For example, when the material determination result is iron and the specular / non-specular determination result is non-specular, the emissivity is determined to be 0.69. Then, the amount of infrared light received by the light receiving element 1a is converted into a temperature using the emissivity determined in step S22 (S23), and this is set as the temperature of the object to be heated 14.

  As described above, according to the third embodiment, since the emissivity is determined in consideration of the material in addition to the specular / non-specular determination result, the temperature can be detected with higher accuracy than in the first embodiment. Become.

  In each of the above embodiments, the light receiving element 1 of the infrared detecting unit 19 is shown as an example of a compound eye type structure in which a plurality of light receiving elements are arranged in a straight line. It is also possible to detect the same detection area as that of the compound eye type by moving this up and down.

It is a perspective view which shows typically the external appearance of the heating cooker which concerns on Embodiment 1 of this invention. It is side surface sectional drawing of FIG. It is a figure which shows the structure of the light receiving element part of the infrared temperature detection part of FIG. It is explanatory drawing of the arrangement position of the light receiving element of the infrared temperature detection part of FIG. It is a figure which shows the detection result by each light receiving element of an infrared temperature detection part in the case of a to-be-heated object with a small emissivity (equivalent to the to-be-heated object of a mirror surface). It is a figure which shows the detection result by each light receiving element of an infrared temperature detection part in the case of a to-be-heated object with high emissivity (equivalent to a to-be-heated object of a non-specular surface). FIG. 2 is a block diagram illustrating a specific configuration of an infrared temperature detection unit in FIG. 1 and a processing unit involved in controlling a heating unit based on a temperature detection result of the infrared temperature detection unit. 3 is a flowchart illustrating a flow of temperature detection processing according to the first embodiment. 6 is a flowchart showing a flow of temperature detection processing according to the second embodiment. It is side surface sectional drawing of the heating cooker of Embodiment 3. FIG. It is a block diagram of the process part in connection with the temperature detection in the heating cooker of Embodiment 3. FIG. 12 is a flowchart illustrating a flow of temperature detection processing according to the third embodiment.

Explanation of symbols

  1 (1a to 1c) Light receiving element, 11 body, 12 top plate, 13 operation unit, 14 object to be heated, 15 display unit, 16 heating unit, 17 drive unit, 18 infrared temperature detection unit, 19 infrared detection unit, 20 temperature Detection unit, 21 Contact temperature detection unit, 22 Control unit, 30 Condensing lens, 31 Scan unit, 32 Amplification unit, 33 Reference temperature element, 41 Signal output unit, 42 Multiplexer unit, 43 A / D conversion unit, 44 Temperature Conversion part, 45 Temperature calculation part, 45a Non-specular surface determination part, 45b Emissivity table, 50 Material determination part.

Claims (9)

A top plate on which the object to be heated is placed;
A heating unit provided under the top plate for heating the object to be heated;
A drive unit for driving the heating unit;
An infrared temperature detector that is disposed above the top plate and detects the temperature of the object to be heated based on the amount of infrared rays emitted from the object to be heated;
A control unit that controls the driving unit based on the temperature of the object to be heated detected by the infrared temperature detection unit, and controls a heating operation of the heating unit;
The infrared temperature detection unit detects temperatures of a plurality of locations in a detection area including a side surface of a heated object placed on the top plate, a boundary between the heated object and the top plate, and the top plate. Then, based on the temperature detection result, it is determined whether the surface state of the object to be heated is a mirror surface or a non-mirror surface. Based on the emissivity set in advance according to the determination result, a predetermined one of the temperatures at the plurality of locations is determined. A heating cooker characterized in that the temperature of the place is corrected to the temperature of the object to be heated.   The infrared temperature detector converts the temperature of the plurality of locations from the amount of infrared rays and provisional emissivity radiated from each of the plurality of locations, determines the mirror surface or non-mirror surface, and after the determination, the determination result The cooking device according to claim 1, wherein a temperature is converted from an emissivity set in advance according to the amount of infrared rays and the amount of infrared rays emitted from the predetermined portion to obtain a temperature of the object to be heated.   The infrared temperature detection unit detects the temperature in a plurality of locations in the vertical direction in the detection area, and among the temperatures of the plurality of locations, the highest temperature and the temperature of the location located at the top of the plurality of locations The cooking device according to claim 1 or 2, wherein when the difference exceeds a predetermined threshold value, it is determined as a mirror surface, and when it is equal to or less than the predetermined threshold value, it is determined as a non-mirror surface.   When the determination result is specular, the highest emissivity of the representative specular emissivity is the emissivity of the specular surface, and when the determination result is non-specular, the emissivity of the typical non-specular surface is obtained. The cooking device according to any one of claims 1 to 3, wherein the lowest emissivity is the emissivity of the non-specular surface.   The cooking device according to any one of claims 1 to 4, wherein when the determination result is a mirror surface, the emissivity is 0.21, and when the determination result is a non-mirror surface, the emissivity is 0.94. .   The contact-type temperature detection unit is disposed so as to be in thermal contact with the back surface of the top plate and detects the temperature of the object to be heated through the top plate, and when the determination result is a mirror surface, the contact type If the temperature detected by the temperature detector is the temperature of the object to be heated, and the determination result is non-specular, the emissivity is 0.94 and the temperature at the predetermined location is corrected to be the temperature of the object to be heated. The cooking device according to any one of claims 1 to 3, characterized in that.   A material determination unit for determining the material of the object to be heated is provided, and the infrared temperature detection unit determines the emissivity in consideration of the determination result of the material determination unit in addition to the determination result of the mirror surface or the non-mirror surface. The cooking device according to any one of claims 1 to 3, wherein a temperature of the predetermined portion is corrected based on the determined emissivity to obtain a temperature of the object to be heated.   The cooking device according to any one of claims 1 to 7, wherein the determination of whether the mirror surface or the non-mirror surface is performed when the temperature of the object to be heated rises above a predetermined temperature.   The cooking device according to any one of claims 1 to 8, wherein the predetermined place is a place located at an uppermost part among the plurality of places.

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