Heating apparatus

Abstract

To provide a heating apparatus capable of shortening thawing time.SOLUTION: A heating apparatus includes a housing containing a heating target, a heating unit for heating the heating target, and a control unit for controlling the heating unit, where the control unit first performs dielectric heating of the heating target by an alternating electric field of a first frequency, and next performs microwave heating of the heating target by a microwave of a second frequency higher than the first frequency.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to heating equipment. [Background technology]

[0002] In recent years, a cooking machine capable of thawing has been developed as an example of a heating appliance, as disclosed in the following Patent Document 1. In the heating appliance disclosed in Patent Document 1, microwave heating and dielectric heating are alternately performed when thawing a frozen object to be heated. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-08246 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned Patent Document 1, microwave heating is performed first, followed by dielectric heating, so that microwave heating and dielectric heating are alternately repeated. According to this technique, microwave heating is performed on a frozen object to be heated at the beginning of the heating process. In this case, the frozen object to be heated absorbs microwave energy and is not thawed. As a result, microwave energy is wasted, and the thawing time of the object to be heated is extended.

[0005] The present disclosure has been made in view of the above-mentioned problems, and an object of the present disclosure is to provide a heating appliance that can shorten the thawing time. [Means for solving the problem]

[0006] The heating device of the present disclosure comprises a housing that contains an object to be heated, a heating unit that heats the object to be heated, and a control unit that controls the heating unit, wherein the control unit first performs dielectric heating of the object to be heated using an alternating electric field of a first frequency, and then performs microwave heating of the object to be heated using microwaves of a second frequency that is higher than the first frequency. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram showing a schematic configuration of a heating device according to a first embodiment. [Figure 2] 4 is a flowchart illustrating processing executed by a control unit of the heating device according to the first embodiment. [Figure 3] 4 is a graph showing the relationship between the temperatures of the surface layer and the center of an object to be heated by the heating device of the first embodiment and the heating time. [Figure 4] FIG. 10 is a diagram showing a schematic configuration of a heating device according to a second embodiment. [Figure 5] 10 is a flowchart illustrating processing executed by a control unit of a heating device according to a second embodiment. [Figure 6] FIG. 10 is a diagram showing a schematic configuration of a heating device according to a third embodiment. [Figure 7] 11 is a flowchart illustrating processing executed by a control unit of a heating device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, a heating device according to an embodiment of the present disclosure will be described with reference to the drawings. In the drawings, the same or equivalent elements are designated by the same reference numerals, and redundant description will not be repeated.

[0009] (Embodiment 1) A heating device 10 according to a first embodiment will be described with reference to FIGS. 1 to 3. FIG.

[0010] FIG. 1 is a diagram showing a schematic configuration of a heating device 10 according to the present embodiment.

[0011] The heating device 10 of this embodiment is a cooking device generally called a microwave oven, but the heating device 10 may be anything that heats the object to be heated OB. The object to be heated OB of this embodiment is foodstuffs, but may be anything that can be heated within the housing 1.

[0012] The heating device 10 includes a housing 1, a heating unit 23, a non-contact temperature sensor 4, a camera 5, an operation panel 6, an antenna 7, and a control unit 8.

[0013] The housing 1 is configured to contain an object to be heated OB. In Fig. 1, a door provided on the housing 1 is not shown.

[0014] The heating unit 23 has the function of heating the object to be heated OB with an alternating electric field E and microwaves M. The heating unit 23 includes a dielectric heater 2 and a microwave heater 3. The dielectric heater 2 has a pair of opposing electrodes. The dielectric heater 2 generates an alternating electric field E between the pair of electrodes, thereby dielectrically heating the object to be heated OB placed between the pair of electrodes. The microwave heater 3 is called a magnetron, and microwave-heats the object to be heated OB by irradiating it with microwaves M.

[0015] In this specification, the heating unit 23 generates an alternating electric field E with a frequency of 10 KHz or more and less than 300 MHz for dielectric heating, and generates microwaves M with a frequency of 300 MHz or more and less than 30 GHz for microwave heating. Dielectric heating is performed to heat the surface layer of the object to be heated OB. Microwave heating is performed to conduct heat from the surface layer to the center of the object to be heated OB. In this embodiment, the frequency of the alternating electric field E for dielectric heating is, for example, 40 MHz, and the frequency of the microwaves M for microwave heating is, for example, 2.45 GHz.

[0016] In this embodiment, heating unit 23 is composed of a dielectric heater 2 and a microwave heater 3, which are provided separately and independently from each other. However, heating unit 23 may be configured to perform both dielectric heating and microwave heating using a single heater.

[0017] The non-contact temperature sensor 4 is composed of an infrared sensor called a thermopile or thermography. The non-contact temperature sensor 4 is provided inside the housing 1. The non-contact temperature sensor 4 is used to estimate the surface temperature of the object to be heated OB using infrared image data generated by detecting infrared rays emitted from the object to be heated OB.

[0018] A camera 5 is also provided inside the housing 1. The camera 5 is an RGB camera that can acquire RGB image data that can identify the color of the surface of the object to be heated OB. The RGB image data is, for example, image data expressed using the three primary colors of red, green, and blue. However, the camera 5 does not have to be an RGB camera. The camera 5 may be, for example, an infrared camera. The camera 5 acquires the RGB image data of the object to be heated OB and transmits the RGB image data to the control unit 8.

[0019] The operation panel 6 has an operation unit that can be operated by a user, and transmits various command signals to the control unit 8 based on the user's operation of the operation unit. For example, when the user operates the operation unit of the operation panel 6, a command signal is transmitted from the operation panel 6 to the control unit 8 instructing the control unit 8 to thaw the object to be heated OB.

[0020] Antenna 7 receives electromagnetic waves reflected by the object to be heated OB (hereinafter simply referred to as "reflected waves"). Based on the intensity of these reflected waves, control unit 8 can determine the degree of thawing of the center of the object to be heated OB. As the thawing of the center of the object to be heated OB progresses, the intensity of the electromagnetic waves reflected by the object to be heated OB increases, and therefore the intensity of the reflected waves received by antenna 7 also increases.

[0021] The control unit 8 is a device called a controller that includes a processor and a memory that stores a program for controlling the operation of the heating device 10. The control unit 8 receives command signals from the operation panel 6, infrared image data of the surface of the heating object OB from the non-contact temperature sensor 4, and RGB image data of the surface of the heating object OB from the camera 5. The control unit 8 controls the heating unit 23 based on the received signals and data.

[0022] The control unit 8 estimates the size and type of the object to be heated OB based on the data of the machine learning results, such as teacher images for each type of food, pre-stored in memory for each size and type of the object to be heated OB, and the RGB image data acquired by the camera 5.

[0023] The control unit 8 also estimates the surface temperature of the heating object OB during thawing based on learning result data, such as teacher images, pre-stored in memory for each size and type of heating object OB, and infrared image data acquired by the non-contact temperature sensor 4. In this embodiment, the control unit 8 determines whether to terminate each of the alternating dielectric heating and microwave heating. Thus, when the control unit 8 determines that the surface temperature of the heating object OB during thawing has reached 0°C or higher, it terminates the dielectric heating by the dielectric heater 2 and starts the microwave heating by the microwave heater 3. Furthermore, when the control unit 8 determines that the surface temperature of the heating object OB during thawing has reached 5°C or higher, it terminates the microwave heating by the microwave heater 3 and terminates the dielectric heating by the dielectric heater 2.

[0024] In addition, the control unit 8 determines the number of times to repeat the dielectric heating and microwave heating, i.e., the conditions for terminating the repeat of the dielectric heating and microwave heating, based on the intensity of the reflected wave from the object to be heated OB acquired by the antenna 7.

[0025] However, the control unit 8 may also determine the duration of each of the alternately repeated dielectric heating and microwave heating and the number of times that the dielectric heating and microwave heating are repeated, based on the estimated size and type of the heating target OB. Details of the determination method in this case will be described in the following embodiment.

[0026] The control unit 8 has a timer that measures time. The control unit 8 uses the timer to measure the time during which the 40 MHz alternating electric field E is applied to the object to be heated OB by the dielectric heater 2 and the time during which the 2.45 GHz microwave is irradiated to the object to be heated OB by the microwave heater 3. The control unit 8 also has a counter that counts the number of times that dielectric heating and microwave heating are repeated.

[0027] To summarize the above, the control unit 8 first performs dielectric heating of the heating object OB using an alternating electric field E of a first frequency, and then performs microwave heating of the heating object OB using microwaves M of a second frequency higher than the first frequency. In this way, dielectric heating, which is effective for thawing the surface layer of the heating object OB, is first performed, and then microwave heating, which is effective for thawing the center of the heating object OB, is performed. This makes it possible to effectively utilize the energy of the microwaves emitted by the heating unit 23, thereby shortening the time it takes to thaw the frozen heating object OB.

[0028] The control unit 8 controls the heating unit 23 to alternately repeat dielectric heating and microwave heating. This repetition allows the surface layer, center, and intermediate portion between the surface layer and center of the object to be heated OB to be thawed uniformly and quickly. Instead of repeating the above-described process, the time for the initial dielectric heating of the object to be heated OB using the alternating electric field E of the first frequency may be extended, and microwave heating of the object to be heated OB using the microwaves M of the second frequency may be performed only once.

[0029] The control unit 8 controls the heating unit 23 to transition from dielectric heating to microwave heating when the surface temperature estimated based on the infrared image data acquired by the non-contact temperature sensor 4 becomes equal to or higher than a first temperature (for example, 0°C). The control unit 8 controls the heating unit 23 to transition from microwave heating to dielectric heating when the surface temperature estimated based on the infrared image data acquired by the non-contact temperature sensor 4 becomes equal to or higher than a second temperature (for example, 5°C).

[0030] More specifically, the control unit 8 determines whether the surface temperature of the heating object OB is equal to or higher than 0°C based on the infrared image data acquired by the non-contact temperature sensor 4. If the control unit 8 determines that the surface temperature of the heating object OB is equal to or higher than 0°C, it terminates the dielectric heating by the dielectric heater 2.

[0031] Furthermore, the control unit 8 determines whether the surface temperature of the heating object OB is 5°C or higher based on the infrared image data acquired by the non-contact temperature sensor 4. When the surface temperature of the heating object OB is 5°C or higher, the control unit 8 ends microwave heating by the microwave heater 3.

[0032] In this embodiment, the control unit 8 determines whether the temperature at the center of the object to be heated OB is equal to or higher than 0°C based on the intensity of the reflected wave from the object to be heated OB received by the antenna 7. When the control unit 8 determines that the temperature at the center of the object to be heated OB is equal to or higher than 0°C, it ends the repeated control of the dielectric heating by the dielectric heater 2 and the microwave heating by the microwave heater 3.

[0033] Whether the temperature at the center of the object to be heated OB is 0°C or higher is determined by whether the intensity of the reflected wave received by the antenna 7 from the object to be heated OB is above a threshold. The control unit 8 determines the threshold based on the image data acquired by the camera 5. The threshold is determined by comparing the image data acquired by the camera 5 with pre-stored teacher image data of an object to be heated similar to the object to be heated OB, to a value that matches the number of repetitions required to thaw the center of the similar teacher image data. This determined threshold is previously obtained by an experiment under the same conditions and stored in the memory of the control unit 8.

[0034] When measuring the surface temperature of the object to be heated OB, the surface includes both the top and side surfaces. If the object to be heated OB has multiple sides, the temperature of only one side surface may be measured, or the temperatures of all of the sides may be measured. The number of points at which the temperature of the surface of the object to be heated OB is measured depends on the size of the object to be heated OB, e.g., food. In this embodiment, the temperature of each of multiple 1 cm x 1 cm sections is measured using an infrared camera. When the object to be heated OB, e.g., food, is placed on a plate, an RGB image is used to recognize the area containing only the food, and the temperature of the area containing only the food is estimated from the infrared image. When determining whether the surface temperature of the object to be heated OB has reached a predetermined temperature, the surface temperature of the object to be heated OB may be the temperature of the entire surface of the object to be heated OB, or it may be the temperature of a partial area of ​​the surface of the object to be heated OB.

[0035] The reason for repeating dielectric heating and microwave heating alternately multiple times in this way is to prevent uneven thawing of the object to be heated. The reason why uneven thawing needs to be prevented is to prevent further heating of the surface layer of the object to be heated OB, which is frozen at the center but has a thawed surface, when microwaves M are used alone for both thawing and heating to a temperature above 0°C. In other words, this is to prevent further heating of the surface layer of thawed food, etc., from destroying the cells in the surface layer of the food, resulting in a loss of flavor and nutrients in the thawed food.

[0036] The control unit 8 terminates the control of repeating the dielectric heating and microwave heating when the intensity of the reflected wave received by the antenna 7 becomes equal to or greater than a threshold value. As described above, in this embodiment, the thawed state of the center of the heating object OB is estimated by receiving the reflected wave from the heating object OB by the antenna 7, so that the thawed state of the heating object OB can be grasped with high accuracy. Therefore, it can be grasped with high accuracy that the thawing of the center of the heating object OB is complete. As a result, the occurrence of uneven thawing of the heating object OB can be suppressed. Therefore, for example, if the heating object OB is food, deterioration in the taste of the thawed food can be suppressed.

[0037] FIG. 2 is a flowchart for explaining the process executed by the control unit of the heating device 10 of this embodiment.

[0038] In step S1, the control unit 8 determines the size and type of the object to be heated OB placed in the housing 1 based on the RGB image data acquired by the camera 5. The control unit 8 compares the RGB image data with teacher image data stored in the memory of the control unit 8, and determines the size and type of the object to be heated OB to be the size and type corresponding to the teacher image data that is most similar to the RGB image data. The control unit 8 also estimates the surface temperature of the object to be heated OB based on the infrared image data of the object to be heated OB acquired by the non-contact temperature sensor 4. The control unit 8 compares the infrared image data with the teacher image data stored in the memory of the control unit 8, and determines the value corresponding to the teacher image data that is most similar to the infrared image data to be the surface temperature of the object to be heated OB.

[0039] In step S2, it is determined whether or not thawing has been selected by the user operating the operation unit of the operation panel 6. If it is determined in step S2 that thawing has been selected by the user operating the operation unit of the operation panel 6, the control unit 8 causes the heating unit 23 to alternately repeat dielectric heating (40 MHz) and microwave heating (2.45 GHz) a predetermined number of times. To this end, in step S3, the control unit 8 compares the RGB image data acquired by the camera 5 with the teacher image data and determines a threshold value for determining the number of times to alternately repeat dielectric heating and microwave heating. The control unit 8 selects a threshold value corresponding to the size and type of the heating object OB determined in step S1 from among multiple threshold value candidates stored in memory.

[0040] In this embodiment, the control unit 8 controls the heating unit 23 to repeat dielectric heating using the alternating electric field E and microwave heating using the microwaves M until the intensity of the reflected waves from the heating object OB acquired by the antenna 7 reaches or exceeds a threshold. In this embodiment, the number of times that the dielectric heating and microwave heating are alternately repeated is not a fixed value, but is the number of times that the intensity of the reflected waves received by the antenna 7 reaches or exceeds a threshold determined based on the RGB image data. Therefore, the number of times that the dielectric heating and microwave heating are alternately repeated is a value that differs depending on the size and type of the heating object OB for which image data is acquired by the camera 5.

[0041] If it is determined in step S2 above that thawing has not been selected by the user's operation of the operation section of the operation panel 6, then in step S11 the control section 8 determines whether or not to heat the surface of the heating object OB to a temperature of 0°C or higher. The control section 8 makes this determination based on whether or not a command signal instructing heating to a temperature of 0°C or higher has been received by the user's operation of the operation section of the operation panel 6. The subsequent processing will be described later.

[0042] In step S4, the control unit 8 causes the dielectric heater 2 to perform dielectric heating of the object to be heated OB using an alternating electric field E with a frequency of 40 MHz. In step S5, the control unit 8 determines whether the temperature of the surface of the object to be heated OB measured by the non-contact temperature sensor 4 is 0°C or higher.

[0043] If it is determined in step S5 that the surface temperature of the heating object OB is not equal to or higher than 0°C, the control unit 8 repeats the processes of steps S4 and S5. On the other hand, if it is determined in step S5 that the surface temperature of the heating object OB is equal to or higher than 0°C, the control unit 8 causes the dielectric heater 2 to end the dielectric heating of the heating object OB using the alternating electric field E with a frequency of 40 MHz in step S6. This is because if the dielectric heating of the heating object OB is continued when the surface temperature of the heating object OB is equal to or higher than 0°C, the surface layer of the heating object OB will reach an unnecessarily high temperature, even though the center of the heating object OB is frozen.

[0044] Therefore, in step S7, the control unit 8 causes the microwave heater 3 to perform microwave heating of the object to be heated OB using 2.45 GHz microwaves. In step S8, the control unit 8 determines whether the temperature of the surface of the object to be heated OB measured by the non-contact temperature sensor 4 is 5°C or higher. If it is determined in step S8 that the temperature of the surface of the object to be heated OB is not 5°C or higher, the control unit 8 determines that microwave heating of the surface layer of the object to be heated OB may be performed, and repeats the processes of steps S7 and S8.

[0045] On the other hand, in step S8, it may be determined that the surface temperature of the heating object OB is 5°C or higher. In this case, in step S9, the control unit 8 determines that dielectric heating of the surface layer of the heating object OB should not be performed in order to prevent uneven thawing of the heating object OB, and causes the microwave heater 3 to terminate microwave heating of the heating object OB. Also in step S9, the control unit 8 measures the intensity of the reflected wave received by the antenna 7 from the surface of the heating object OB.

[0046] In step S10, the control unit 8 determines whether the reflected wave from the object to be heated OB received by the antenna 7 is equal to or greater than the threshold determined in step S3. If the reflected wave from the object to be heated OB is not equal to or greater than the threshold determined in step S3 in step S10, the control unit 8 determines that the center of the object to be heated OB has not yet been thawed, and repeats steps S4 to S10.

[0047] On the other hand, in step S10, if the reflected wave from the heating object OB is equal to or greater than the threshold determined in step S3, the control unit 8 determines that the center of the heating object OB has already been thawed, and terminates the repeated control of the heating object OB using the alternating electric field E and microwaves N. Thereafter, in step S11, the control unit 8 determines whether or not to heat the heating object OB to a temperature of 0°C or higher. If it is determined in step S11 that the heating object OB will not be heated to a temperature of 0°C or higher, the control unit 8 terminates all processing.

[0048] On the other hand, if it is determined in step S11 that the surface of the heating object OB is to be heated to 0°C or higher, then in step S12, the control unit 8 starts microwave heating of the heating object OB using microwaves M with a frequency of 2.45 GHz. After that, when a predetermined time has elapsed, in step S13, the control unit 8 ends microwave heating of the heating object OB using microwaves with a frequency of 2.45 GHz.

[0049] Next, a method for generating learning data by machine learning used in step S3 of this embodiment will be described. This method includes the following steps (1) to (6).

[0050] Step (1): Measure the size of a rectangular parallelepiped object to be heated OB, for example, a food ingredient such as a piece of beef. In this measurement, RGB image data is acquired by the camera 5 (RGB camera) inside the heating appliance 10, and the sizes of the three sides of the rectangular parallelepiped object to be heated OB are determined based on the acquired RGB image data. Alternatively, the sizes of the three sides of the rectangular parallelepiped object to be heated OB may be measured with a ruler.

[0051] Step (2): Dielectric heating is performed on the object to be heated OB by applying an alternating electric field E with a frequency of 40 MHz using the dielectric heater 2. In this state, the time until the temperature of the top and side surfaces of the object to be heated OB reaches a temperature of 0°C or higher is measured. In addition, the temperature of the center of the object to be heated OB at the moment when the temperature of the top and side surfaces of the object to be heated OB reaches a temperature of 0°C or higher is measured by inserting a thermometer frozen to -20°C into the center of the object to be heated OB. The temperature of the top and side surfaces of the object to be heated OB may be measured using the non-contact temperature sensor 4, or may be measured using a thermometer frozen to -20°C. At this time, the room temperature may also be measured.

[0052] Step (3): Immediately after dielectric heating by the 40 MHz alternating electric field E of the dielectric heater 2 is stopped, microwave heating by the microwave heater 3 using microwaves M with a frequency of 2.45 GHz is started. This microwave heating is continued until the top and side surfaces of the object to be heated OB reach a temperature of 5°C or higher. The time it takes for the top and side surfaces of the rectangular parallelepiped object to be heated OB to reach a temperature of 5°C or higher and the temperature of the center of the object to be heated OB at the time when the top and side surfaces of the rectangular parallelepiped object to be heated OB reach a temperature of 5°C or higher are recorded. At this time, the room temperature may also be recorded.

[0053] Step (4): Immediately after the temperature of the top and sides of the rectangular parallelepiped object to be heated OB reaches 5°C or higher, the intensity of the 2.45 GHz microwaves M reflected from the object to be heated OB is acquired by antenna 7. Note that as the temperature of the center of the object to be heated OB approaches 0°C from a negative temperature, the intensity of the reflected waves of the microwaves M increases. Therefore, when the intensity of the reflected waves reaches or exceeds a threshold, it can be assumed that the center of the object to be heated OB has thawed.

[0054] (5): Immediately after the temperature of the top and side surfaces of the rectangular parallelepiped heating object OB reaches 5°C or higher, microwave heating of the heating object OB using microwaves M with a frequency of 2.45 GHz is stopped. After that, dielectric heating of the heating object OB using an alternating electric field E with a frequency of 40 MHz is performed again until the temperature of the top and side surfaces of the heating object OB reaches 0°C or higher. This is because the temperature of the surface layer of the heating object OB returns to a value below 0°C due to the transfer of heat from the surface layer of the heating object OB to the center of the heating object OB.

[0055] The time it takes for the temperature of the top and side surfaces of the object to be heated OB to reach 5°C or higher, and the temperature of the center of the object to be heated OB at the time when the temperature of the top and side surfaces of the object to be heated OB reaches 5°C or higher, are recorded. At this time, room temperature may also be measured.

[0056] Step (6): Repeat steps (3) to (5) above until the temperature at the center of the object to be heated OB reaches 0°C.

[0057] The data obtained from the above experiments (1) to (6) are the temperature at the center of the heated object OB, room temperature, and the intensity of the reflected wave when the top and sides of the heated object OB reach 5°C or higher, depending on the number of times dielectric heating and microwave heating are repeated for each size and type of food.

[0058] FIG. 3 is a graph showing the relationship between the temperatures of the surface layer and the center of the object to be heated OB heated by the heating device 10 of this embodiment and the heating time. This is a chart.

[0059] 3, it can be seen that when the object to be heated OB is subjected to dielectric heating using the alternating electric field E and microwave heating using the microwaves M in this order, the heating time until the center of the object to be heated OB is thawed is shortened. This will be explained in detail below.

[0060] When thawing a frozen object to be heated OB, a heating device 10 such as a typical microwave oven irradiates the object to be heated OB with microwaves M. As a result, the surface of the object to be heated OB, which reaches a temperature of 0°C or higher, becomes liquid. Thereafter, as can be seen from the long-dashed line graph of the surface portion at 2.45 GHz in FIG. 3, the surface of the liquid object to be heated OB rapidly becomes hot. Meanwhile, as can be seen from the solid line graph of the center portion at 2.45 GHz in FIG. 3, the center of the object to be heated OB is still frozen. This results in so-called uneven thawing of the object to be heated OB.

[0061] Furthermore, when the object to be heated OB is dielectrically heated using an alternating electric field E, as can be seen from the dotted line graph of the surface layer at 40 MHz in Figure 3 and the short dashed line graph of the center at 40 MHz in Figure 3, it takes a long time to thaw both the surface layer and the center of the object to be heated OB.

[0062] On the other hand, the heating device 10 of the present embodiment alternately performs dielectric heating using the alternating electric field E and microwave heating using microwaves M. As a result, as can be seen from the graph of the alternate center portion shown by the dashed dotted line in Fig. 3 and the graph of the alternate surface portion shown by the dashed dotted line in Fig. 3, it is possible to thaw the object to be heated OB down to its center in a short time while suppressing the occurrence of uneven thawing.

[0063] Although a thermopile or thermography such as the non-contact temperature sensor 4 can measure the temperature of the surface layer of the object to be heated OB, it cannot estimate the temperature of the center of the object to be heated OB. For this reason, in this embodiment, an antenna 7 is used that receives waves reflected by the object to be heated OB. When the object to be heated OB is in a frozen state, the 2.45 GHz microwaves are easily absorbed by the object to be heated OB, and therefore the amount of energy received by the antenna 7 as reflected waves is small.

[0064] On the other hand, as thawing progresses and only the center of the object to be heated OB remains frozen, the amount of microwaves reflected by the object to be heated OB increases, and the amount of energy of the reflected waves received by the antenna 7 increases. Therefore, by measuring the amount of energy of the waves reflected from the object to be heated OB, it is possible to estimate the degree of thawing of the center of the object to be heated OB.

[0065] However, the amount of energy of the reflected wave received by the antenna 7 differs depending on the size and type of the object to be heated OB. Therefore, even if the center of the object to be heated OB is thawed to the same degree, the amount of energy of the reflected wave differs depending on the size and type of the object to be heated OB.

[0066] Therefore, the size and type of the object to be heated OB are identified based on the image data acquired by the camera 5. Thereby, a threshold value for the amount of energy of the reflected wave when the center of the object to be heated OB is thawed is determined in advance according to the combination of the size and type of the object to be heated OB. As a result, it becomes possible to thaw the object to be heated OB in an optimal state all the way to the center while preventing overheating or under-thawing, that is, preventing uneven thawing.

[0067] The threshold value of the energy amount of the reflected wave from the heating object OB when the heating object OB is thawed to the center for each size and type of heating object OB is determined by machine learning. Information input to the machine learning model includes, for example, the size, type, and surface temperature of the heating object OB before thawing begins.

[0068] The method for determining the threshold value is described in detail below. Note that the numbers in parentheses after the step numbers below are the values ​​on the horizontal axis of the graph in Figure 3, and the units of the values ​​are seconds as a unit of time. The vertical axis in Figure 3 indicates the temperature values.

[0069] Step 0 (during the manufacturing stage of the heating equipment 10): Using image data acquired by the camera 5, the amount of energy of the reflected waves from the heating object OB when it is thawed to the center is estimated for each size and type of heating object OB, and the threshold value of the reflected waves received by the antenna 7 is determined.

[0070] Step 1 (0-70): Dielectric heating is performed by irradiating the object to be heated OB with a 40 MHz alternating electric field E until the temperature of the surface of the object to be heated OB reaches 0°C or higher. Note that when the temperature of the surface of the object to be heated OB is below 0°C, the heating rate of the surface of the object to be heated OB is greater with the 40 MHz alternating electric field E than with the 2.45 GHz microwave M.

[0071] Step 2 (70-80): Heating is performed using 2.45 GHz microwaves M until the temperature of the surface of the object to be heated OB reaches 5°C or higher. Note that when the temperature of the surface of the object to be heated OB is 0°C or higher, the 2.45 GHz microwaves M heat the object to be heated OB at a faster rate than the 40 MHz alternating electric field E.

[0072] Step 3 (80-100): The surface of the object to be heated OB, which has reached a temperature of 5°C or higher, is cooled to a temperature of 0°C or below as heat is absorbed by the center of the object to be heated OB, which has a temperature of 0°C or below.

[0073] Step 4 (80 to 130): The object to be heated OB is heated by the 40 MHz alternating electric field E until the temperature of the surface layer of the object to be heated OB again reaches 0°C or higher.

[0074] Step 5 (130 to 220): Repeat the above steps 1 to 4 until the amount of energy of the reflected wave from the object to be heated OB becomes equal to or greater than the threshold value.

[0075] Step 6 (220): When the amount of energy of the reflected wave from the heating object OB exceeds the threshold, the heating unit 23 ends the alternating repetition of dielectric heating of the frozen heating object OB using the alternating electric field E and microwave heating using the microwaves M. In other words, the thawing of the heating object OB is completed.

[0076] (Embodiment 2) The heating device 10 of the second embodiment will be described with reference to Figures 4 and 5. Note that the following description will not be repeated regarding the same points as those of the heating device 10 of the first embodiment. The heating device 10 of the present embodiment differs from the heating device 10 of the first embodiment in the following points.

[0077] FIG. 4 is a diagram showing a schematic configuration of the heating device 10 of this embodiment.

[0078] As shown in FIG. 4, the heating device 10 of this embodiment differs from the heating device 10 of the first embodiment in that the antenna 7 is not provided.

[0079] In this embodiment, the control unit 8 determines the number of repetitions of dielectric heating and microwave heating based on image data acquired by the camera 5 instead of the reflected waves received by the antenna 7. Specifically, the control unit 8 compares the RGB image data acquired by the camera 5 with a large number of teacher image data previously acquired by machine learning. The control unit 8 determines the number of repetitions of dielectric heating and microwave heating based on the comparison results. In this comparison, the number of repetitions corresponding to the teacher image data of a size and type similar to the size and type of the heating target OB is adopted as the result.

[0080] This number of repetitions is the number of times that dielectric heating and microwave heating are repeated until the center of the heating object OB is thawed, which is determined from the results of a heating experiment on the heating object OB. When dielectric heating and microwave heating have been repeated the number of times determined by the comparison, the control unit 8 ends the control of repeating dielectric heating and microwave heating.

[0081] According to the heating device 10 of this embodiment, the antenna 7 is not necessary, so the number of parts of the heating device 10 can be reduced and the structure of the heating device 10 can be simplified.

[0082] FIG. 5 is a flowchart for explaining the process executed by the control unit 8 of the heating device 10 according to the embodiment.

[0083] Step S3A of this embodiment differs from the process (step S3) of the control unit 8 of embodiment 1 in that the control unit 8 determines the number of times to repeat induction heating and microwave heating based on RGB image data acquired by the camera 5. Also, step 9A differs from the process (step 9) of the control unit 8 of embodiment 1 in that the control unit 8 ends microwave heating using 2.45 GHz microwaves M without measuring the intensity of the reflected wave. Furthermore, step S10A of this embodiment differs from the process (step S10) of the control unit 8 of embodiment 1 in that the control unit 8 repeats induction heating and microwave heating the number of times determined in step S3A.

[0084] The processing of the steps other than the above-mentioned steps by the control unit 8 of this embodiment is the same as the processing of each step in the first embodiment.

[0085] (Embodiment 3) The heating device 10 of the second embodiment will be described with reference to Figures 6 and 7. Note that the following description will not be repeated regarding the same points as those of the heating device 10 of the first embodiment. The heating device 10 of the present embodiment differs from the heating device 10 of the first embodiment in the following points.

[0086] FIG. 6 is a diagram showing a schematic configuration of the heating device 10 of this embodiment.

[0087] The heating appliance 10 of this embodiment is a commercial heating appliance. In the heating appliance 10, a two-dimensional code attached to a packaging bag of a heating object OB, such as food, whose size, shape, and type are predetermined, is read from RGB image data acquired by the camera 5. This determines the number of repetitions of dielectric heating and microwave heating for the heating object OB, as well as the first heating time of dielectric heating and the second heating time of microwave heating. Note that the two-dimensional code is, for example, a QR code (registered trademark), which is an example of a mark read using the camera R. Any mark, such as a one-dimensional code, may be used as long as it can be acquired from image data. In other words, the mark may be a barcode (registered trademark), or the like, as long as it can be used to determine the predetermined number of repetitions of dielectric heating and microwave heating for the heating object OB, as well as the first heating time of dielectric heating and the second heating time of microwave heating.

[0088] 6, the heating device 10 of this embodiment differs from the heating device 10 of the first embodiment in that it is not provided with the non-contact temperature sensor 4 and the antenna 7. Therefore, the number of parts of the heating device 10 can be significantly reduced, and the structure of the heating device 10 can be made extremely simple.

[0089] In this embodiment, as in the second embodiment, the control unit 8 determines the number of times that dielectric heating and microwave heating are repeated based on the image data acquired by the camera 5. Specifically, the control unit 8 reads a two-dimensional code from the image data acquired by the camera 5, thereby determining the number of times that dielectric heating and microwave heating of the heating object OB are repeated.

[0090] The control unit 8 terminates the control of repeating the dielectric heating and microwave heating when the dielectric heating and microwave heating have been repeated the number of times specified by the two-dimensional code. This number of repetitions is determined in advance through heating experiments in which dielectric heating and microwave heating are repeated on a heating object OB similar to the heating object OB placed in a packaging bag. The determined number of repetitions of dielectric heating and microwave heating of the heating object can be specified by the RGB image data of the two-dimensional code.

[0091] Specifically, in this embodiment, unlike the first and second embodiments, the control unit 8 determines the first heating time of the dielectric heating and the second heating time of the microwave heating based on a two-dimensional code included in the image data acquired by the camera 5. Furthermore, in this embodiment, the control unit 8 terminates the dielectric heating when the first heating time specified by the two-dimensional code has elapsed since the start of the dielectric heating. Furthermore, in this embodiment, the control unit 8 terminates the microwave heating when the second heating time specified by the two-dimensional code has elapsed since the start of the microwave heating.

[0092] FIG. 7 is a flowchart for explaining the processing executed by the control unit 8 of the heating device 10 of this embodiment.

[0093] In this embodiment, in step S2B, the control unit 8 determines whether or not prior information (marker) such as a two-dimensional code is attached to the packaging bag or the like of the object to be heated OB, based on the RGB image data acquired by the camera 5. In step S2B, if a marker such as a two-dimensional code is not attached to the packaging bag or the like of the object to be heated OB, the control unit 8 executes the process of step S11.

[0094] On the other hand, if it is determined in step S2B that a mark such as a two-dimensional code is attached to the packaging bag of the heating object OB, the control unit 8 determines the number of repetitions of alternating heating, the first heating time, and the second heating time based on the mark in step S3B. Also, in step 9B, microwave heating using the 2.45 GHz microwaves M is terminated without measuring the intensity of the wave reflected from the heating object OB.

[0095] In step S5B, the control unit 8 determines whether the dielectric heating at 40 MHz has been performed for the first heating time determined based on the two-dimensional code. If it is determined that the dielectric heating has been performed for the first heating time, the control unit 8 ends the dielectric heating at 40 MHz in step S6.

[0096] In step S8B, the control unit 8 determines whether the microwaves at 2.45 GHz have been applied for the second heating time determined based on the two-dimensional code. If it is determined that the microwave heating has been applied for the second heating time, the control unit 8 ends the microwave heating at 2.45 GHz in step S9B. Note that in step S9B, the intensity of the reflected waves from the object to be heated OB is not specified.

[0097] Furthermore, in step S10B of this embodiment, the control unit 8 determines whether or not the dielectric heating and microwave heating have been repeated the predetermined number of times determined in step S3B. If the control unit 8 determines that the dielectric heating and microwave heating have been repeated the predetermined number of times determined in step S3B, the control unit 8 determines in step S11 whether or not to heat the heating object OB to a temperature of 0°C or higher.

[0098] The processing of steps other than the above-mentioned steps by the control unit 8 of this embodiment is the same as the processing of each step in the first embodiment. [Explanation of symbols]

[0099] 1 chassis 2. Dielectric heater 3 Microwave heater 4. Non-contact temperature sensor (thermopile or thermography) 5 cameras (RGB cameras) 6 Operation panel 7 Antenna 8. Control unit (controller) 10 Heating equipment 23 Heating section E electric field M Microwave

Claims

1. a housing that contains an object to be heated; a heating unit that heats the object to be heated; a control unit that controls the heating unit, the control unit first performs dielectric heating of the object to be heated using an alternating electric field of a first frequency, and then performs microwave heating of the object to be heated using microwaves of a second frequency higher than the first frequency. heating equipment.

2. The control unit controls the heating unit so as to alternately repeat the dielectric heating and the microwave heating. The heating device according to claim 1 .

3. a camera provided in the housing to acquire image data of the object to be heated; an antenna for receiving a wave reflected by the object to be heated, The control unit determining a threshold based on the image data acquired by the camera; When the intensity of the reflected wave received by the antenna becomes equal to or greater than the threshold value, the control of repeating the dielectric heating and the microwave heating is terminated. The heating device according to claim 2.

4. Further, a camera is provided in the housing to acquire image data of the object to be heated, The control unit determining the number of repetitions of the dielectric heating and the microwave heating based on the image data acquired by the camera; When the dielectric heating and the microwave heating have been repeated the number of times, the control for repeating the dielectric heating and the microwave heating is terminated. The heating device according to claim 2.

5. The heating device further includes a camera provided in the housing to acquire image data of the object to be heated, The control unit determining a first heating time for performing the dielectric heating and a second heating time for performing the microwave heating based on the image data acquired by the camera; When the first heating time has elapsed since the start of the dielectric heating, the dielectric heating is terminated; When the second heating time has elapsed since the start of the microwave heating, the microwave heating is terminated. The heating device according to claim 1 .

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