Heating machine

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] This disclosure relates to heating equipment.

Background Art

[0002] In recent years, as disclosed in Patent Document 1 below, as an example of heating equipment, the development of a cooking heater capable of performing thawing has been carried out. In the heating equipment disclosed in Patent Document 1, when thawing a frozen object to be heated, stomach microwave heating and dielectric heating are alternately performed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1 described above, first microwave heating is performed, and then dielectric heating is performed, whereby stomach microwave heating and dielectric heating are alternately repeated. According to this technique, microwave heating is performed on the frozen object to be heated at the beginning of the heat treatment. In this case, since the frozen object to be heated absorbs the energy of the microwaves, it is not thawed. As a result, the energy of the microwaves is wasted, and subject the thawing time of the object to be heated becomes longer.

[0005] This disclosure has been made in view of the above problems. An object of this disclosure is to provide a heating device capable of shortening the thawing time.

Means for Solving the Problems

[0006] The heating device of this disclosure comprises a housing that encloses 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 by an alternating electric field of a first frequency, and then performs microwave heating of the object to be heated by microwaves of a second frequency higher than the first frequency. [Brief explanation of the drawing]

[0007] [Figure 1] This is a diagram showing the schematic configuration of the heating device according to Embodiment 1. [Figure 2] This is a flowchart illustrating the process performed by the control unit of the heating device in Embodiment 1. [Figure 3] This graph shows the relationship between the temperature of the surface and core of an object being heated by the heating device of Embodiment 1 and the heating time. [Figure 4] This diagram shows the schematic configuration of the heating device according to Embodiment 2. [Figure 5] This is a flowchart illustrating the process performed by the control unit of the heating device in Embodiment 2. [Figure 6] This diagram shows the schematic configuration of the heating device according to Embodiment 3. [Figure 7] This is a flowchart illustrating the process performed by the control unit of the heating device in Embodiment 3. [Modes for carrying out the invention]

[0008] Hereinafter, the heating equipment of the embodiment of this disclosure will be described with reference to the drawings. In the drawings, the same or equivalent elements will be denoted by the same reference numerals, and redundant descriptions will not be repeated.

[0009] (Embodiment 1) The heating device 10 of Embodiment 1 will be explained using Figures 1 to 3.

[0010] Figure 1 is a diagram showing the schematic configuration of the heating device 10 in this embodiment.

[0011] The heating device 10 in this embodiment is a cooking appliance generally called a microwave oven, but the heating device 10 can be any device that heats the object to be heated OB. The object to be heated OB in this embodiment is food, but it can be any object that can be heated inside the housing 1.

[0012] The heating device 10 comprises 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 enclosure 1 is configured to enclose the object to be heated OB. In Figure 1, the door provided on the enclosure 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 a magnetron, and microwaves 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 in dielectric heating, and generates microwaves M with a frequency of 300 MHz or more and less than 30 GHz in 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, the heating unit 23 is composed of a dielectric heater 2 and a microwave heater 3 that are provided separately and independently from each other. However, the 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 temperature of the surface of the heating object OB by using infrared image data generated by detecting infrared rays emitted from the heating object OB.

[0018] The camera 5 is also provided inside the housing 1. The camera 5 is an RGB camera that can acquire RGB image data capable of specifying the color of the surface of the heating object OB. The RGB image data is, for example, image data expressed by the three primary colors of red, green, and blue. However, the camera 5 may not be an RGB camera. The camera 5 may be, for example, an infrared camera or the like. The camera 5 acquires the RGB image data of the heating object 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 the user, and transmits various command signals to the control unit 8 based on the user's operation on the operation unit. For example, when the user operates the operation unit of the operation panel 6, a command signal for instructing the thawing of the heating object OB is transmitted from the operation panel 6 to the control unit 8.

[0020] The antenna 7 receives electromagnetic waves (hereinafter, also simply referred to as "reflected waves") reflected by the heating object OB. Based on the intensity of this reflected wave, the control unit 8 can grasp the degree of thawing of the central portion of the heating object OB. Note that as the thawing of the central portion of the heating target portion OB progresses, the intensity of the electromagnetic wave reflected by the heating object OB increases, so the intensity of the reflected wave received by the antenna 7 increases.

[0021] The control unit 8 is a device called a controller, which has a memory and processor that store 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 object to be heated OB from the non-contact temperature sensor 4, and RGB image data of the surface of the object to be heated OB from the camera 5. Based on the received signals and data, the control unit 8 controls the heating unit 23.

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

[0023] Furthermore, the control unit 8 estimates the surface temperature of the object OB being heated during thawing based on the learning result data, such as training images, which are pre-stored in memory for each size and type of the object OB to be heated, and the infrared image data acquired by the non-contact temperature sensor 4. In this embodiment, the control unit 8 decides whether or not to terminate each of the dielectric heating and microwave heating processes, which are repeated. As a result, if the control unit 8 determines that the surface temperature of the object OB being heated during thawing has risen to 0°C or higher, it terminates the dielectric heating by the dielectric heater 2 and starts the microwave heating by the microwave heater 3. Also, if the control unit 8 determines that the surface temperature of the object OB being heated during thawing has risen to 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] Furthermore, the control unit 8 determines the number of times dielectric heating and microwave heating are repeated, that is, the conditions for ending the repeated dielectric heating and microwave heating, based on the intensity of the reflected waves at the object OB to be heated, which is acquired by the antenna 7.

[0025] However, the control unit 8 may determine the execution time of each of the alternating dielectric heating and microwave heating processes, and the number of times the dielectric heating and microwave heating processes are repeated, based on the estimated size and type of the object to be heated OB. Details of the determination method in this case will be described in subsequent embodiments.

[0026] The control unit 8 has a timer for timing. The control unit 8 uses the timer to time the 40 MHz alternating electric field E applied to the object OB being heated by the dielectric heater 2, and the 2.45 GHz microwave irradiation time applied to the object OB by the microwave heater 3. The control unit 8 also has a counter for counting the number of times the dielectric heating and microwave heating cycles are repeated.

[0027] In summary, the control unit 8 first performs dielectric heating of the object to be heated OB using an alternating electric field E of a first frequency, and then performs microwave heating of the object to be heated 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 object to be heated OB, is performed first, followed by microwave heating, which is effective for thawing the center of the object to be heated OB. Therefore, the energy of the microwaves emitted by the heating unit 23 can be effectively utilized, and the thawing time of the frozen object to be heated OB can be shortened.

[0028] The control unit 8 controls the heating unit 23 to alternately repeat dielectric heating and microwave heating. This repetition allows for uniform and rapid thawing of the surface, core, and intermediate portion between the surface and core of the object to be heated OB. Alternatively, instead of repeating as described above, the dielectric heating time of the object to be heated OB with the first frequency alternating electric field E may be extended, and microwave heating of the object to be heated OB with the second frequency microwave M may be performed only once.

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

[0030] More specifically, the control unit 8 determines whether the surface temperature of the object to be heated OB is 0°C or higher 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 object to be heated OB is 0°C or higher, it terminates the dielectric heating by the dielectric heater 2.

[0031] Furthermore, the control unit 8 determines whether the surface temperature of the object to be heated OB is 5°C or higher based on the infrared image data acquired by the non-contact temperature sensor 4. If the surface temperature of the object to be heated OB is 5°C or higher, the control unit 8 terminates 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 0°C or higher based on the intensity of the reflected wave received by the antenna 7 from the object to be heated OB. If the control unit 8 determines that the temperature at the center of the object to be heated OB is 0°C or higher, it terminates the repeated control of dielectric heating by the dielectric heater 2 and microwave heating by the microwave heater 3.

[0033] Whether the temperature of 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 antenna 7 from the object to be heated OB exceeds a threshold. The control unit 8 determines the threshold based on the image data acquired by camera 5. The threshold is determined by comparing the image data acquired by camera 5 with pre-stored training image data of an object to be heated similar to the object to be heated OB, and is set to a value that matches the number of repetitions required to defrost the center of the similar training image data. This determined threshold is obtained in advance through experiments under the same conditions and is 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 all of the top and sides. If the object to be heated OB has multiple sides, the temperature of only one side may be measured, or the temperature of all of the multiple sides may be measured. The number of measurement points for the surface temperature of the object to be heated OB depends on the size of the object to be heated OB, for example, food. In this embodiment, the temperature of each of the multiple sections, each measuring 1 cm x 1 cm, is measured using an infrared camera. If the object to be heated OB, for example, food placed on a plate, the temperature of the food-only area is estimated from the infrared image by recognizing the food-only area using an RGB 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 part of the surface of the object to be heated OB.

[0035] The reason for alternating between dielectric heating and microwave heating multiple times is to suppress uneven thawing of the object being heated. The need to suppress uneven thawing arises because using only microwaves (M) for both thawing and heating to temperatures above 0°C would further overheat the surface layer of an object (OB) that is frozen in the center but thawed on the surface. In other words, further heating of the surface layer of thawed food would destroy the cells in the surface layer, resulting in a loss of flavor and nutrients.

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

[0037] Figure 2 is a flowchart illustrating the process performed by the control unit of the heating device 10 in this embodiment.

[0038] In step S1, the control unit 8 determines the size and type of the object to be heated OB placed inside the housing 1 based on the RGB image data acquired by the camera 5. The control unit 8 compares the RGB image data with the training image data stored in the control unit 8's memory and determines the size and type of the object to be heated OB to correspond to the training 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 training image data stored in the control unit 8's memory and determines the value corresponding to the training image data that is most similar to the infrared image data to determine the surface temperature of the object to be heated OB.

[0039] In step S2, the control unit 8 determines whether defrosting has been selected by operating the user's control panel 6. If it is determined in step S2 that defrosting has been selected by operating the user's control 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 training image data and determines a threshold for determining the number of times to alternately repeat dielectric heating and microwave heating. From among a plurality of threshold candidate values ​​stored in memory, the control unit 8 selects a threshold corresponding to the size and type of the object to be heated OB determined in step S1.

[0040] In this embodiment, the control unit 8 controls the heating unit 23 to repeat dielectric heating by alternating electric field E and microwave heating by microwave M until the intensity of the reflected wave from the object to be heated OB, acquired by the antenna 7, exceeds a threshold. In this embodiment, the number of times the alternating dielectric heating and microwave heating are repeated is not a fixed number, but rather the number of times when the intensity of the reflected wave received by the antenna 7 exceeds a threshold determined based on the RGB image data. Therefore, the number of times the alternating dielectric heating and microwave heating are repeated is a different value depending on the size and type of the object to be heated OB, whose image data is acquired by the camera 5.

[0041] In step S2 described above, if it is determined that defrosting has not been selected by the user's operation of the control panel 6, in step S11, the control unit 8 determines whether or not to heat the surface of the object to be heated OB to a temperature of 0°C or higher. The control unit 8 makes this determination based on whether or not it has received a command signal from the user instructing heating to a temperature of 0°C or higher by the user's operation of the control 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 surface temperature of the object to be heated OB, as measured by the non-contact temperature sensor 4, is 0°C or higher.

[0043] In step S5, if it is determined that the surface temperature of the object to be heated OB is not 0°C or higher, the control unit 8 repeats the processes of steps S4 and S5. On the other hand, in step S5, if it is determined that the surface temperature of the object to be heated OB is 0°C or higher, in step S6, the control unit 8 terminates the dielectric heating of the object to be heated OB by the alternating electric field E with a frequency of 40 MHz in the dielectric heater 2. This is because if dielectric heating of the object to be heated OB is continued while the surface temperature of the object to be heated OB is 0°C or higher, the surface layer of the object to be heated OB will become excessively hot, even though the center of the object to be heated OB remains 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 surface temperature of the object to be heated OB, as measured by the non-contact temperature sensor 4, is 5°C or higher. If, in step S8, it is determined that the surface temperature of the object to be heated OB is not 5°C or higher, the control unit 8 decides that microwave heating of the surface layer of the object to be heated OB may be performed, and repeats the processes in steps S7 and S8.

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

[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, in step S10, the reflected wave from the object to be heated OB is not equal to or greater than the threshold determined in step S3, the control unit 8 assumes that the center of the object to be heated OB is not yet thawed and repeats steps S4 to S10.

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

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

[0049] Next, we will describe the method for creating training data using machine learning as used in step S3 of this embodiment. This method comprises the following steps (1) to (6).

[0050] Step (1): Measure the size of the rectangular object to be heated OB, such as a piece of beef or other food ingredient. In this measurement, RGB image data is acquired by the camera 5 (RGB camera) inside the heating device 10, and the dimensions of the three sides of the rectangular object to be heated OB are determined based on the acquired RGB image data. Alternatively, the dimensions of the three sides of the rectangular 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. While this is being done, the time it takes for the temperature of the top surface and sides of the object to be heated OB to reach a temperature of 0°C or higher is measured. At the same time, the temperature of the center of the object to be heated OB at the point when the temperature of the top surface and sides of the object to be heated OB reaches a temperature of 0°C or higher is measured by inserting a thermometer that has been frozen to -20°C into the center of the object to be heated OB. Note that the temperature of the top surface and sides of the object to be heated OB may be measured using a non-contact temperature sensor 4, or it may be measured using a thermometer that has been frozen to -20°C. At this time, the room temperature may also be measured.

[0052] Step (3): Immediately after stopping the dielectric heating by the alternating electric field E with a frequency of 40 MHz from the dielectric heater 2, microwave heating by the microwave heater 3 with a frequency of 2.45 GHz microwave M is started. This microwave heating is carried out until the top and sides of the object to be heated OB reach a temperature of 5°C or higher. The time taken for the top and sides of the rectangular 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 the top and sides of the rectangular 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 top and sides of the rectangular object OB reach a temperature of 5°C or higher, the intensity of the reflected microwave M at 2.45 GHz is obtained by antenna 7. Note that as the temperature of the center of the object OB approaches 0°C from negative temperatures, the intensity of the reflected microwave M increases. Therefore, if the intensity of the reflected wave exceeds a threshold, it can be estimated that the center of the object OB has thawed.

[0054] (5) Immediately after the top and sides of the rectangular object OB reach a temperature of 5°C or higher, microwave heating of the object OB with a frequency of 2.45 GHz is stopped. Then, dielectric heating of the object OB with an alternating electric field E at a frequency of 40 MHz is performed again until the temperature of the top and sides of the object OB reaches a temperature of 0°C or higher. This is because the heat from the surface of the object OB moves to the center of the object OB, causing the surface temperature of the object OB to return to a value of 0°C or lower.

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

[0056] Step (6): Repeat steps (3) through (5) above until the temperature of 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, the 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 size and type of food and the number of repeated dielectric heating and microwave heating cycles.

[0058] Figure 3 is a graph showing the relationship between the temperature of the surface and the center of the object OB being heated by the heating device 10 of this embodiment, and the heating time. This is a chart.

[0059] Figure 3 shows that when the object OB is heated alternately using dielectric heating with an alternating electric field E and microwave heating with microwaves M in this order, the heating time until the center of the object OB is thawed is shortened. This will be explained in detail below.

[0060] In thawing a frozen object OB, a typical heating device 10 such as a microwave oven irradiates the object OB with microwaves M. As a result, the surface layer of the object OB, which has risen above 0 degrees Celsius, becomes liquid. Subsequently, as can be seen from the long dashed line graph of the 2.45 GHz surface layer in Figure 3, the liquid surface layer of the object OB rapidly becomes hot. On the other hand, as can be seen from the solid line graph of the 2.45 GHz center in Figure 3, the center of the object OB remains frozen. Therefore, uneven thawing occurs in the object OB.

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

[0062] On the other hand, in the heating device 10 of this embodiment, dielectric heating by an alternating electric field E and microwave heating by microwaves M are performed alternately. As a result, as can be seen from the dashed-dotted line graph of the alternating central part and the dashed-dotted line graph of the alternating surface part in Figure 3, the center of the object to be heated OB can be thawed in a short time while suppressing the occurrence of uneven thawing.

[0063] While a thermopile or thermograph, such as the non-contact temperature sensor 4, can measure the temperature of the surface layer of the object OB being heated, it cannot estimate the temperature of the center of the object OB. Therefore, in this embodiment, an antenna 7 is used to receive reflected waves reflected by the object OB being heated. When the object OB is frozen, 2.45 GHz microwaves are easily absorbed by the object OB, so the amount of energy received by the antenna 7 as reflected waves is small.

[0064] On the other hand, as thawing progresses and the frozen portion becomes limited to the center of the object being heated OB, the amount of microwaves reflected from the object OB increases. As a result, the amount of energy of the reflected waves received by antenna 7 increases. Therefore, by measuring the amount of energy of the reflected waves from the object OB, it is possible to estimate the degree of thawing in the center of the object OB.

[0065] However, the amount of energy in the reflected waves received by antenna 7 varies depending on the size and type of the object being heated OB. Therefore, even if the center of the object being heated OB is thawed to the same extent, the amount of energy in the reflected waves will differ depending on the size and type of the object being heated OB.

[0066] Therefore, the size and type of the object to be heated OB are identified based on the image data acquired by camera 5. This allows for the pre-determining of the energy level of the reflected wave when the center of the object OB is thawed, depending on the combination of size and type of the object OB. As a result, it becomes possible to thaw the object OB to its center in an optimal state while suppressing overheating or under-thawing, that is, while suppressing uneven thawing.

[0067] The threshold energy level of the reflected wave at the heated object OB when it is thawed to the core, for each size and type of heated object OB, is determined by machine learning. The information input to the machine learning model includes, for example, the size, type, and surface temperature of the heated object OB before thawing begins.

[0068] The following details the method for determining the aforementioned threshold. Note that the numbers in parentheses after the step numbers below represent the values ​​on the horizontal axis of the graph in Figure 3, and the unit of time is seconds. The vertical axis of Figure 3 represents the temperature value.

[0069] Step 0 (during the manufacturing stage of the heating device 10): Based on the image data acquired by the camera 5, the amount of energy of the reflected wave from the heated object OB in a state where the center of the heated object OB has been thawed is estimated for each size and type of heated object OB, and the threshold of the reflected wave to be 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 surface temperature of the object to be heated OB reaches 0°C or higher. Note that if the surface temperature 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): Heat the object OB using a 2.45 GHz microwave M until the surface temperature reaches 5°C or higher. Note that if the surface temperature of the object OB is 0°C or higher, the 2.45 GHz microwave M will heat the object OB faster than the 40 MHz alternating electric field E.

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

[0073] Step 4 (80-130): Heat the object OB with a 40 MHz alternating electric field E until the surface of the object OB returns to a temperature of 0°C or higher.

[0074] Step 5 (130-220): Repeat steps 1 through 4 described above until the amount of reflected wave energy at the heating object OB exceeds the threshold.

[0075] Step 6 (220): When the energy of the reflected wave from the object to be heated OB exceeds the threshold, the heating unit 23 terminates the alternating repeated dielectric heating of the frozen object to be heated OB by the alternating electric field E and microwave heating by the microwave M. In other words, the thawing of the object to be heated OB is completed.

[0076] (Embodiment 2) The heating device 10 of Embodiment 2 will be described using Figures 4 and 5. Note that the same aspects as those of the heating device 10 of Embodiment 1 will not be repeated below. The heating device 10 of this embodiment differs from the heating device 10 of Embodiment 1 in the following respects.

[0077] Figure 4 shows a schematic configuration of the heating device 10 in this embodiment.

[0078] As shown in Figure 4, the heating device 10 of this embodiment differs from the heating device 10 of Embodiment 1 in that it does not have an antenna 7.

[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 wave 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 training image data acquired in advance by machine learning. Based on the comparison result, the control unit 8 determines the number of repetitions of dielectric heating and microwave heating. In this comparison, the number of repetitions corresponding to training image data of a size and type similar to the object to be heated OB is adopted as the result.

[0080] This number of repetitions is the number of times dielectric heating and microwave heating are repeated until the center of the object OB is thawed, as determined from the results of heating experiments on the object OB. The control unit 8 terminates the control of repeating dielectric heating and microwave heating when the dielectric heating and microwave heating have been repeated the number of times determined by this comparison.

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

[0082] Figure 5 is a flowchart illustrating the process performed by the control unit 8 of the heating device 10 in this embodiment.

[0083] In step S3A of this embodiment, the control unit 8 differs from the control unit 8 of Embodiment 1 (step S3) in that it determines the number of times the induction heating and microwave heating cycles are repeated based on the RGB image data acquired by the camera 5. Also, in step 9A, it differs from the control unit 8 of Embodiment 1 (step 9) in that it terminates the microwave heating with a 2.45 GHz microwave M without measuring the intensity of the reflected wave. Furthermore, in step S10A of this embodiment, the control unit 8 differs from the control unit 8 of Embodiment 1 (step S10) in that it repeats the dielectric heating and microwave heating cycles the number of times determined in step S3A.

[0084] The processing of steps other than those described above in 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 Embodiment 2 will be described using Figures 6 and 7. Note that the same aspects as those of the heating device 10 of Embodiment 1 will not be repeated below. The heating device 10 of this embodiment differs from the heating device 10 of Embodiment 1 in the following respects.

[0086] Figure 6 shows a schematic configuration of the heating device 10 in this embodiment.

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

[0088] As shown in Figure 6, the heating device 10 of this embodiment differs from the heating device 10 of Embodiment 1 in that it does not have a non-contact temperature sensor 4 and an antenna 7. Therefore, the number of parts in 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 well, similar to Embodiment 2, the control unit 8 determines the number of repetitions of dielectric heating and microwave heating based on image data acquired by the camera 5. Specifically, the control unit 8 determines the number of repetitions of dielectric heating and microwave heating of the object to be heated OB by reading a two-dimensional code from the image data acquired by the camera 5.

[0090] The control unit 8 terminates the control of repeating dielectric heating and microwave heating when the dielectric heating and microwave heating have been repeated a number of times specified by the two-dimensional code. This number of repetitions is predetermined by repeated heating experiments of a heating object OB similar to the heating object OB placed in a packaging bag, using dielectric heating and microwave heating. 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 embodiments 1 and 2, the control unit 8 determines the first heating time for dielectric heating and the second heating time for microwave heating based on the two-dimensional code contained in the image data acquired by the camera 5. Furthermore, in this embodiment, the control unit 8 terminates dielectric heating when the first heating time specified by the two-dimensional code has elapsed from the start of dielectric heating. In addition, in this embodiment, the control unit 8 terminates microwave heating when the second heating time specified by the two-dimensional code has elapsed from the start of microwave heating.

[0092] Figure 7 is a flowchart illustrating the process performed by the control unit 8 of the heating device 10 in this embodiment.

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

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

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

[0096] Furthermore, in step S8B, the control unit 8 determines whether the microwave heating at 2.45 GHz has been performed for the second heating time determined based on the two-dimensional code. If the control unit 8 determines that the microwave heating has been performed for the second heating time, in step S9B, the microwave heating at 2.45 GHz is terminated. Note that in step 9B, the intensity of the reflected wave from the object to be heated OB is not determined.

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

[0098] The processing of steps other than those described above in 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 cabinet 2 Dielectric heater 3. Microwave heater 4. Non-contact temperature sensor (thermopile or thermography) 5. Camera (RGB camera) 6. Control Panel 7 Antennas 8. Control Unit (Controller) 10 Heating equipment 23 Heating section E electric field M Microwave

Claims

1. A housing that encloses the object to be heated, A heating unit for heating the object to be heated, The system comprises a control unit for controlling the heating unit, The control unit, First, dielectric heating of the object to be heated is performed using an alternating electric field of a first frequency, then microwave heating of the object to be heated is performed using microwaves of a second frequency higher than the first frequency, and further, The heating unit is controlled to alternately repeat the dielectric heating and the microwave heating. The system further comprises an antenna that receives reflected waves reflected from the object to be heated, A heating device in which the control unit terminates the control of repeating dielectric heating and microwave heating based on the intensity of the reflected wave received by the antenna.

2. A housing that encloses the object to be heated, A heating unit for heating the object to be heated, The system comprises a control unit for controlling 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, then performs microwave heating of the object to be heated using microwaves of a second frequency higher than the first frequency, and further, The control unit controls the heating unit so that dielectric heating and microwave heating are repeated alternately. A camera is provided inside the housing to acquire image data of the object to be heated, The system further comprises an antenna that receives reflected waves reflected from the object to be heated, The control unit, A threshold is determined based on the image data acquired by the aforementioned camera. When the intensity of the reflected wave received by the antenna exceeds the threshold, the control that repeats the dielectric heating and microwave heating is terminated. heating equipment.

3. A housing that encloses the object to be heated, A heating unit for heating the object to be heated, The system comprises a control unit for controlling 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, then performs microwave heating of the object to be heated using microwaves of a second frequency higher than the first frequency, and further, The control unit controls the heating unit so that dielectric heating and microwave heating are repeated alternately. The housing further includes a camera installed to acquire image data of the object to be heated, The control unit, Based on the image data acquired by the camera, the number of repetitions of dielectric heating and microwave heating is determined. When the dielectric heating and the microwave heating have been repeated the specified number of times, the control for repeating the dielectric heating and the microwave heating is terminated. heating equipment.

4. A housing that encloses the object to be heated, A heating unit for heating the object to be heated, The system comprises a control unit for controlling 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. The housing further includes a camera installed to acquire image data of the object to be heated, The control unit, Based on the image data acquired by the camera, a first heating time for performing dielectric heating and a second heating time for performing microwave heating are determined. When the first heating time has elapsed since the start of dielectric heating, the dielectric heating is terminated. When the second heating time has elapsed from the start of the microwave heating, the microwave heating is terminated. heating equipment.

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