WO2023199559A1

WO2023199559A1 - High-frequency heating cooker

Info

Publication number: WO2023199559A1
Application number: PCT/JP2023/000294
Authority: WO
Inventors: 恵安島; 香織竹中; 友秀松井
Original assignee: 日立グローバルライフソリューションズ株式会社
Priority date: 2022-04-15
Filing date: 2023-01-10
Publication date: 2023-10-19
Also published as: JP2023157706A

Abstract

Provided is a high-frequency heating cooker that, if a plurality of items to be heated are successively heated and cooked, can determine the current placement location of an item to be heated, even if the temperature at a placement location etc. of an item to be heated has risen during a previous execution of heating. The invention is provided with: a range heating unit for heating an item to be heated that has been placed onto a table plate; an infrared sensor for detecting temperatures at a plurality of spots on an upper surface of the table plate; an outside temperature sensor for detecting the outside temperature outside a heating chamber; and a control unit for controlling the range heating unit on the basis of the temperature detected by the infrared sensor. The control unit: calculates the temperature difference between the outside temperature and a backside temperature of the table plate, and also the temperature difference between the outside temperature and a frontside temperature of the table plate; uses the backside temperature as a table plate temperature if the former temperature difference is small, and uses the frontside temperature as the table plate temperature if the latter temperature difference is small; and determines a region of the upper surface of the table plate where there is a temperature difference from the table plate temperature to be a placement region for an item to be heated.

Description

High frequency heating cooker

The present invention relates to a high-frequency cooking device that uses microwaves to cook food.

Some conventional high-frequency heating cookers set the cooking time using microwaves based on the preservation state of the food placed in the heating chamber. For example, the abstract of Patent Document 1 describes a high-frequency cooking device that "makes it possible to heat the object to an appropriate temperature regardless of the storage state, amount, or initial surface temperature of the object." a heating means for heating the object to be heated; a table plate on which the object to be heated is placed in the heating chamber; a weight sensor for supporting the table plate and measuring the weight of the object to be heated; a temperature sensor that detects the temperature, and a control means that controls the heating means based on the detected values of the weight sensor and the temperature sensor so as to reach the finished temperature, and the control means is configured to control the heated The temperature sensor detects a temperature rise when the object is being heated, and depending on the detected temperature rise, it is determined whether the object to be heated is in a frozen state or not, and the object to be heated is in a frozen state. A device is disclosed that calculates a heating time according to storage conditions and heats an object to be heated. Further, claim 5 of the same document states that "the temperature sensor is an infrared sensor."

As described above, in the high-frequency heating cooker of Patent Document 1, it is determined whether or not the object to be heated is in a frozen state based on the temperature rise of the object to be heated detected by the non-contact temperature sensor (infrared sensor). By calculating the cooking time according to the determination result, the object to be heated is appropriately cooked (see FIGS. 13 to 15 of the same document).

JP2019-211171A

However, the high-frequency heating device of Patent Document 1 does not assume a situation in which one food is cooked and then another food is successively cooked, and the latter food may not be properly cooked in some cases. . This problem will be specifically explained using an example of a situation in which rice is heated after heating a side dish.

In this case, when the side dish is heated, the temperature of the part of the table plate on which the side dish is placed also rises, so when the side dish is taken out after cooking, there will be a part on the top surface of the table plate that is hotter than room temperature. After that, when the rice is placed in a position different from the place where the side dishes are placed and cooking is started, the temperature sensor (infrared sensor) of Patent Document 1 detects that the high temperature area on the top surface of the table plate is the food to be cooked (the object to be heated). It is not possible to determine whether or not. Therefore, the high-frequency heating device of Patent Document 1 misunderstands the high-temperature area on the top surface of the table plate (where the side dishes were placed until just before) as the object to be heated, and based on the temperature change there, inappropriately heats the rice. There was a possibility that the time would be calculated, and there was a risk that the rice would be insufficiently heated.

Therefore, in the case of successively heating and cooking a plurality of objects to be heated, even if the temperature of the place where the objects to be heated are increased during the previous heating, the current location of the objects to be heated can be adjusted. An object of the present invention is to provide a high-frequency heating cooker that can be specified.

The high-frequency heating cooker of the present invention has been made to achieve the above object, and includes a heating chamber housing a table plate, a microwave heating section that heats an object placed on the table plate, and a microwave heating section that heats an object placed on the table plate. an infrared sensor that detects temperatures at multiple locations on the top surface of the table plate; an outside temperature sensor that detects the outside temperature of the heating chamber; and a control unit that controls the microwave heating section based on the temperature detected by the infrared sensor. The control unit calculates a temperature difference between the temperature outside the refrigerator and a temperature on the back side of the table plate, and a temperature difference between the temperature outside the refrigerator and the temperature on the front side of the table plate, and calculates the temperature difference between the outside temperature and the temperature on the front side of the table plate. If the difference is small, the back side temperature is used as the table plate temperature, and if the latter temperature difference is small, the front side temperature is used as the table plate temperature, and the area on the top surface of the table plate is used as the table plate temperature. A portion having a temperature difference from the table plate temperature is determined to be the placement area of the object to be heated.

According to the high-frequency heating cooker of the present invention, when heating and cooking a plurality of objects to be heated in succession, even if the temperature of the place where the objects to be heated have risen during the previous heating, the current It is possible to specify the location where objects are installed.

FIG. 1 is a front perspective view of a heating cooker according to an embodiment. FIG. 2 is a rear perspective view of the heating cooker according to one embodiment with the outer frame removed. AA sectional view in Figure 1 In Figure 3, an explanation diagram of the operation of the infrared sensor when heating cold rice in a bowl. An explanatory diagram of the operation of the infrared sensor in FIG. 3 when heating the frozen rice wrapped in plastic wrap. FIG. 3 is an enlarged sectional view illustrating a reference position of an infrared sensor. FIG. 3 is an enlarged cross-sectional view illustrating the end point position of an infrared sensor. FIG. 3 is an enlarged cross-sectional view illustrating a state in which the observation window of the infrared sensor is closed. FIG. 3 is an explanatory diagram illustrating a temperature measurement area of an infrared sensor. 1 is a flowchart illustrating the first stage of control of a heating cooker according to an embodiment. 2 is a flowchart illustrating the latter stage of control of the heating cooker according to an embodiment. FIG. 2 is a control block diagram of a heating cooker according to an embodiment. The figure explaining the heating time of the heating cooker based on one Example.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

Figures 1 to 3 show the main parts of this embodiment. Figure 1 is a perspective view of the cooking device main body as seen from the front side, and Figure 2 is a perspective view of the main body of the cooking device viewed from the rear side with the outer frame removed. The perspective view shown in FIG. 3 is a sectional view taken along the line AA in FIG.

In the figure, the main body 1 of the cooking device places food to be heated in a heating chamber 28 and cooks the food using microwaves, heat from a heater, and superheated steam.

The door 2 is opened and closed to take food into and out of the heating chamber 28. By closing the door 2, the heating chamber 28 is sealed, preventing leakage of microwaves used when heating food. Contains heater heat and superheated steam, making it possible to heat efficiently.

The handle 9 is attached to the door 2 to facilitate opening and closing of the door 2, and has a shape that is easy to grip with the hand.

The glass window 3 is attached to the door 2 so that the state of the food being cooked can be checked, and is made of glass that can withstand high temperatures caused by heat generated by a heater or the like.

The input unit 71 is provided on the operation panel 4 on the lower front side of the door 2, and includes an operation unit 6 for inputting a heating unit such as microwave heating or heater heating, heating time, heating temperature, etc. It is comprised of a display section 5 that displays the contents inputted from and the progress state of cooking.

The outer frame 7 is a cabinet that covers the top surface and left and right side surfaces of the main body 1 of the cooking device.

The water tank 42 is a container that stores water necessary for producing heated steam, and is provided at the lower front of the main body 1 of the heating cooker, and has a structure that can be attached and detached from the front of the main body 1 to supply water. and easy drainage.

The rear plate 10 forms the rear surface of the above-mentioned cabinet, and an external exhaust duct 18 is attached to the upper part to collect the steam discharged from the food and the cooling air (waste heat) after cooling the internal parts of the main body 1. 39 is discharged from the external exhaust port 8 of the external exhaust duct 18.

The machine room 20 is provided in a space between the bottom surface 28a of the heating chamber and the bottom plate 21 of the main body 1, and on the bottom plate 21 there is a magnetron 33 for heating food, a waveguide 47 connected to the magnetron 33, A control board 23 on which a control unit 23a (see FIG. 12) is mounted, various other components to be described later, a fan device 15 for cooling these various components, and the like are attached.

The bottom surface 28a of the heating chamber has a concave shape approximately in the center, and the rotating antenna 26 is installed in the bottom surface 28a, and the microwave energy radiated from the magnetron 33 is passed through the waveguide 47 and the output shaft 46a of the rotating antenna 26. The heat flows into the lower surface of the rotary antenna 26 through the opening 47a, is diffused by the rotary antenna 26, and is radiated into the heating chamber 28. An output shaft 46a of the rotary antenna 26 is connected to a rotary antenna drive section 46.

The fan device 15 is composed of a cooling fan attached to a cooling motor attached to the bottom plate 21. The cooling air 39 generated by the fan device 15 cools the self-heating magnetron 33, an inverter circuit (not shown), the back weight sensor 25c, the left weight sensor 25b, etc. in the machine room 20. Further, the hot air flows between the outside of the heating chamber 28 and the outer frame 7 and between the hot air case 11a and the rear plate 10 as described above, cooling the outer frame 7 and the rear plate 10 while cooling the outer exhaust port 8 of the external exhaust duct 18. more excreted. Further, a duct 16a for cooling a hot air motor 13 (described later) and a duct 16b for cooling an infrared unit 50 housed in an infrared case 48 (described later) are provided, and the cooling air 39 that has cooled the infrared unit 50 is provided. The exhaust heat (water vapor, etc.) in the heating chamber 28 is discharged from the opposite side of the exhaust duct 28e for discarding it, and then exhausted to the outside through the external exhaust duct 18.

The microwave heating section 330 (FIG. 12) includes a magnetron 33 and an inverter circuit (not shown), and is controlled by the control section 23a. The temperature of an IGBT (not shown) in the inverter circuit is detected by an IGBT temperature sensor 101.

A hot air unit 11 is attached to the rear part of the heating chamber 28, and a hot air fan 32 is attached to the hot air unit 11 to efficiently circulate the air in the heating chamber 28. An air passage is provided in the rear wall surface 28b of the heating chamber. A hot air intake hole 31 and a hot air blowout hole 30 are provided.

The hot air fan 32 is rotated by the drive of the hot air motor 13 attached to the outside of the hot air case 11a, and the hot air heater 14 heats the circulating air.

Further, the hot air unit 11 includes a hot air case 11a provided on the rear side of the heating chamber back wall surface 28b, and a hot air fan 32 and a hot air heater 14 located on the outer peripheral side thereof. A hot air motor 13 is attached to the rear side of the hot air case 11a, and the motor shaft is connected to a hot air fan 32 through a hole provided in the hot air case 11a.

The temperature of the hot air motor 13 increases due to the heat from the heating chamber 28 and the hot air heater 14. To prevent this, the hot air motor 13 is surrounded by a hot air motor cover 17 and is formed into a substantially cylindrical shape to connect the duct 16a to the hot air case 11a and the rear plate 10. The upper end opening of the duct 16a is connected to the lower surface of the hot air motor cover 17, and the lower end opening of the duct 16a is connected to the outlet of the fan device 15, so that a part of the cooling air 39 from the fan device 15 is It is taken into the hot air motor cover 17.

A grill heating section 12 consisting of a heater is attached to the back side of the heating chamber top surface 28c of the heating chamber 28. The grill heating section 12 is formed into a planar shape by winding a heater wire around a mica plate, and is pressed and fixed against the back side of the top surface of the heating chamber 28 to heat the top surface of the heating chamber 28 and heat the food in the heating chamber 28. It is baked using radiant heat.

Further, an infrared unit 50, which will be described later, is provided on the back side of the heating chamber top surface 28c of the heating chamber 28, and is covered with an infrared case 48 to cool the infrared unit 50. The duct 16b is located between the hot air case 11a and the rear plate 10, the upper end opening of the duct 16b is connected to the side surface of the infrared rays case 48, the lower end opening is connected to the upper surface of the hot air motor cover 17, and the cooling air from the fan device 15 is connected to the duct 16b. I'm trying to incorporate some of the 39.

An internal temperature sensor 80 (thermistor) that detects the ambient temperature of the heating chamber 28 (hereinafter referred to as "internal temperature Ti") is provided on the left back side of the heating chamber top surface 28c of the heating chamber 28.

Further, a plurality of weight sensors 25 are provided on the bottom surface 28a of the heating chamber, for example, a left side weight sensor 25b, a right side weight sensor (not shown) on the left and right sides of the front side, and a back side weight sensor 25c at the center of the rear side. A table plate 24 is placed thereon.

The table plate 24 is for placing food, and is made of a material that is heat resistant and has good microwave transparency so that it can be used for both heater heating and microwave heating.

The boiler 43 is attached to the outer surface of the hot air case 11a of the hot air unit 11, and exposes saturated steam to the inside of the hot air unit 11. The saturated steam ejected into the hot air unit 11 is heated by the hot air heater 14 and becomes superheated steam.

The pump unit 87 pumps water from the water tank 42 to the boiler 43, and is composed of a pump and a motor that drives the pump. Adjustment of the amount of water supplied to the boiler 43 is determined by the ON/OFF ratio of the motor.

The heating parts include a range heating part 330, a hot air heater 14, a hot air motor 13, a grill heating part 12, a boiler 43, etc.

Next, the infrared sensor 52, which is provided above the heating chamber 28 and detects the temperature of the heated object in a non-contact manner, will be described in detail with reference to FIGS. 4 to 9.

Figure 4 is an explanatory diagram of the operation of an infrared sensor when rice is heated in a bowl using the cross-sectional diagram shown in Figure 3. Figure 5 is an illustration of the operation of an infrared sensor when rice is heated in a bowl using the cross-sectional diagram shown in Figure 3. An explanatory diagram of the operation of the infrared sensor when heating. FIG. 6 is an explanatory enlarged view of the infrared sensor section showing the reference position. FIG. 7 is an explanatory enlarged view of the infrared sensor showing the end point position. FIG. 9 is an explanatory enlarged view of the infrared sensor showing a state in which the window is closed. FIG. 9 is an explanatory view for explaining the field of view of the infrared sensor.

Reference numeral 51 denotes a motor, and the motor 51 is installed so that the direction of the motor 51 is parallel to the rotating shaft 51a and the inner wall surface 28b of the heating chamber. The rotating shaft 51a rotates (drives) a cylindrical unit case 54 (described later), thereby rotating the board 53 on which the infrared sensor 52 housed in the unit case 54 is mounted, thereby directing the lens portion 52a of the infrared sensor 52. The temperature can be detected by rotationally moving the range from the back side of the heating chamber bottom surface 28a (heating chamber back wall surface 28b side) to the heating chamber opening 28d. The motor 51 uses a stepping motor, and under the control of a control section 23a provided on the control board 23, the rotating shaft 51a can be rotated in the normal direction, reverse direction, or rotated at a desired rotation angle.

52 is an infrared sensor that detects the temperature of the table plate 24 and the object to be heated 60c in a non-contact manner. In this embodiment, the infrared sensor 52 is configured by arranging eight infrared detection elements (for example, thermopiles) on a substrate 53 in a row in the direction of the rotation axis 51a. Therefore, the infrared sensor 52 of this embodiment can simultaneously detect the temperatures at eight locations on the table plate 24. Further, the infrared sensor 52 of this embodiment can detect the temperature of the entire area of the table plate 24 by rotating the substrate 53 on which the infrared detection element group is installed around the rotation axis 51a (see FIGS. 6 and 7). I have to.

Reference numeral 54 designates a cylindrical unit case, which has a substrate 53 disposed at its largest diameter portion and a window portion 54a through which the lens portion 52a of the infrared sensor 52 is exposed. Further, by incorporating carbon into the material of the unit case 54, the characteristic of the unit case 54 is made to be a conductive material, thereby preventing external noise from entering the unit case 54.

55 is a shutter made of a metal plate. The shutter 55 closes the observation window 44a, which will be described later, when the infrared sensor 52 is not used (see FIG. 8). Further, in order to prevent the temperature of the heating chamber 28 from being transmitted to the unit case 54, an air passage 55c with a gap is formed along the outer periphery of the unit case 54 so that cooling air can flow around the outer periphery of the unit case 54. A shutter 55 is disposed in the air passage 55c, and an opening 55a and an opening 55b are provided in the air passage 55c to serve as an entrance and exit for the cooling air 39.

Reference numeral 56 denotes a positioning convex portion, and when the control unit 23a controls the rotation of the motor 51 so that the detection point of the infrared sensor 52 is aligned with the reference position (detection point a in FIG. 4), the reference position of the detection point of the infrared sensor 52 is set. In order to correct this, when the observation window 44a is closed by the shutter 55, the rotating shaft 51a is allowed to slip while the positioning protrusion 56 is in contact with a stopper (not shown) provided on the infrared case 48. , the position of the detection point a, which is the reference position controlled by the control unit 23a and the reference position detected by the infrared sensor 52, can be corrected. 44 is an arc-shaped observation part protruding inward of the heating chamber 28; The rotation center of the shaft 51a, the center of the cylindrical unit case 54, the center of the arc of the shutter 55 provided along the outer periphery of the unit case 54 and bent into an arc, and the center positions of the arc-shaped observation section 44 are as follows. All are in the same location. Reference numeral 44a denotes an observation window provided in the observation section 44, which opens the range that is the visual field detected by the infrared sensor 52. Further, in order to prevent microwave leakage from the observation window 44a during microwave heating, a raised wall (burring) 44b of about 2 mm is provided outside the observation window 44a.

By protruding the observation section 44 inside the heating chamber 28, it is possible to detect a wide range of temperatures within the minimum narrow observation window opening range.

Numeral 49 is a convex portion that separates the infrared case 48 and the infrared unit 50 from the top surface 28c of the heating chamber.By making only the convex portion 49 in contact with the top surface 28c of the heating chamber, the grill heating section 12 and hot air are removed during heating. The temperature of the top surface 28c of the heating chamber heated by the heater such as the unit 11 is made difficult to be transmitted to the infrared unit 50.

Reference numeral 100 denotes an outside temperature sensor disposed on the board 53 in the infrared unit 50, which detects the outside temperature To outside the heating chamber 28. In addition, when heating multiple objects to be heated continuously, the outside temperature To measured before the start of heating for the first time is almost equal to the room temperature outside the cooking device, and Although the outside temperature To is higher than the room temperature outside the cooking device, it is lower than the inside temperature Ti.

The procedure for measuring the infrared sensor 52 of the control unit 23a mounted on the control board 23 will be explained with reference to FIGS. 4 and 5.

FIG. 4 is a diagram illustrating the operation of the infrared sensor when heating rice in a bowl, and FIG. 5 is a diagram illustrating the operation of the infrared sensor when heating frozen rice wrapped in plastic wrap. In FIG. 4, the surface of the object to be heated 60c can be directly detected at the detection point f. In FIG. 5, the surface of the object to be heated 60c is detected through the edible wrap.

The infrared sensor 52 measures 8 points at once, and moves the infrared sensor 52 14 times at 3 degrees each from the reference position (Fig. 4, detection point a) to the end point position (Fig. 4, detection point h) using the motor 51. , a total of 15 rows are measured by rotating and moving, and temperatures are detected at 120 locations: 8 points in the left-right direction x 15 rows in the front-back direction. From the end point position to the reference position, the infrared sensor 52 does not perform any measurement and directly returns to the reference position.

Temperature detection is carried out by moving the infrared sensor 52 14 times in increments of 3 degrees from the reference position to the end point position, measuring in 15 rows, and repeating the process of returning from the end point position to the reference position. Processing of the measured temperature will be described later.

Next, the rotational movement of the infrared sensor 52 will be explained.

As shown in FIG. 4, when a rice bowl containing an object to be heated (rice) 60c is placed on the table plate 24 provided on the bottom surface 28a of the heat chamber and heating is started, the magnetron 33 stably transmits signals for 1 to 2 seconds. The shutter 55 closes the observation window 44a (see FIG. 8) to prevent noise from entering the infrared sensor 52 due to unstable transmission when the magnetron 33 starts transmitting.

After the transmission of the magnetron 33 becomes stable, the control unit 23a controls the rotating shaft 51a of the motor 51 to rotate to the reference position. When the rotating shaft 51a rotates to the reference position, the unit case 54 is rotated, and the orientation of the lens portion 52a of the infrared sensor 52 is also rotated to a position where the detection point a at the reference position can be detected (see FIGS. 4 and 6). . At this time, the cooling air 39 flows through the lens portion 52a of the infrared sensor 52 and flows from the sensor window portion 44a to the heating chamber 28, thereby preventing dirt from adhering to the lens portion 52a.

By rotating the unit case 54, the temperature of the heated object 60c is detected from the reference position (detection point a) to the detection point b and c of the table plate 24, and when the unit case 54 is further rotated, The temperature outside the bowl (container 60) is detected in the height direction, and the temperature from detection point d to detection point e is detected. After the detection point reaches the top of the opening of the bowl (container 60), the temperature on the surface of the heated object 60c is detected at the detection point f, and then the temperature inside the bowl (container 60) is detected at the detection point g. Then, the temperature of the table plate 24 is detected at a detection point h.

Detection of the temperature in the temperature detection range from detection point a to detection point h is performed on one side of the outward rotation of the unit case 54, and once the temperature has been detected up to the end point, the temperature is not detected on the return trip without measuring it midway. Instead, return to the reference position again and repeat the process from detection point a to detection point h in sequence.

The number of temperature detections can be changed as desired, and the detection points a to h described above are illustrative examples and measure 15 columns of data as described above.

Further, temperature detection is performed by stopping the rotation of the motor 51 while the temperature is being detected, and then rotating the motor 51 after the temperature has been detected. In order to accurately detect temperature, it is better to stop rotation and measure.

For example, at the beginning of heating, the rotation of the unit case 54 is stopped and detected, after detection, it is rotated at a certain angle, the rotation is stopped and detected, and after detection, it is rotated at a certain angle, which are repeated to form a grid pattern. to measure the temperature distribution. By doing so, the entire surface of the table plate 24 is evenly measured by measuring the temperature at a fixed position at equal angles.

The infrared sensor 52 is provided at approximately the center in the left-right direction of the heating chamber top surface 28c inside an imaginary line extending perpendicularly to the heating chamber top surface 28c from the four sides of the table plate 24 placed on the heating chamber bottom surface 28a. There is.

The field of view of the infrared sensor 52 is such that the detection point a and the detection point h are roughly set in a range that detects the temperature of the front and rear flanges of the table plate 24, and the sensors on both sides of the arrayed plurality of elements of the infrared sensor 52 are set on the table plate 24. The temperature of the left and right flange portions of 24 is approximately determined within the range for detecting the temperature. By doing so, it becomes possible to accurately detect the temperature of the object to be heated 60c placed approximately at the center of the table plate 24. Further, it is better to rotate the infrared sensor 52 so that the temperature measurement range is wide, so as to detect the temperature of the object to be heated 60c placed in the container 60.

With this setting, when the container 60 is placed on the back side of the table plate 24, the temperature of the object to be heated 60c in the bowl can be detected at the detection point b located approximately below the infrared sensor 52, and the temperature of the object to be heated 60c in the bowl can be detected. When placed on one of the left and right sides of the table plate 24, since the infrared sensor 52 is provided approximately in the center of the heating chamber 28 in the left and right direction, the infrared sensors 52 are arranged in a line provided in the infrared sensor 52. The temperature of the object to be heated 60c can be detected by the eight-element infrared sensors on both sides.

Further, when the weight information is light and the temperature distribution is recognized to be increasing over a wide range from the weight information from the weight sensor 25 and the temperature distribution information detected by the infrared sensor 52, it can be determined that the object to be heated 60c is thin and wide.

In this embodiment, the method of detecting the temperature of the object to be heated 60c placed in the container 60 has been described in detail. Since the temperature of the side surface and the top surface can be detected, it is possible to detect the temperature distribution of the heated object 60c in detail.

<Temperature measurement procedure of infrared sensor 52>
Next, processing of the temperature measured by the infrared sensor 52 will be explained.

First, a problem when measuring the temperature of the object to be heated 60c on the table plate 24 using the infrared sensor 52 will be explained. The infrared detection element (thermopile) used in the infrared sensor 52 of this embodiment is an element that outputs the average value of the temperature of the object to be measured within the field of view as the detected temperature. Therefore, when the object to be heated 60c and the table plate 24 are present within the field of view of the infrared detection element, not only the temperature of both but also the area ratio of both within the field of view will be reflected in the measured temperature.

The infrared sensor 52 of this embodiment measures the upper surface of the table plate 24 by dividing it into a plurality of regions so that the approximate size and shape of the object to be heated 60c placed on the table plate 24 can be recognized. For example, in the case of an infrared sensor 52 having eight infrared detection elements, by moving the rotating shaft 51a of the motor 51 14 times by 3 degrees, the upper surface of the table plate 24 can be moved 120 ( The temperature can be measured in 8×15) areas.

Hereinafter, each of the 120 squares shown in FIG. 9 will be referred to as a pixel. This pixel is set at a viewing angle that is approximately 50% or more of the directional characteristic of the infrared sensor 52. However, the output from the infrared sensor 52 includes all objects to be measured within the field of view (100% viewing angle), including the following: This includes a pixel whose viewing angle has a viewing angle of 50% or more of the directional characteristic, a plurality of pixels adjacent to the pixel, and a wall surface of the heating chamber 28 other than the table plate 24. Therefore, it is necessary to roughly calculate the temperature of the heated object 60c by correcting the detected temperature.

The information necessary for the correction is the table plate temperature Tt, the recognition (judgment) of the heated object 60c, and the size and temperature of the recognized heated object 60c.

Here, the table plate temperature Tt is a temperature suitable for use after detecting the back side temperature Tb (average temperature of 8 pixels on the back side) and the front side temperature Tf (average temperature of 8 pixels on the front side) of the table plate 24. is the table plate temperature Tt. Note that the details of which one to select as the table plate temperature Tt will be described later.

<Method for recognizing heated object 60c>
Next, a method for recognizing the heated object 60c based on the measured temperature of each pixel, and the recognized size and temperature of the heated object 60c will be described.

The object to be heated 60c is recognized by recognizing a pixel having a temperature difference of a predetermined value or more with respect to the table plate temperature Tt (that is, the temperature Tb on the back side or the temperature Tf on the front side of the table plate 24) as the object to be heated 60c. do. However, since the object to be heated 60c may be at a wide range of temperatures such as frozen, refrigerated, or room temperature, the following determination method is used to recognize the object to be heated 60c.

Since heating cookers are mainly placed in the kitchen, the temperature of the heating cooker is about the same as room temperature, except immediately after it is used for heating.

When the heated object 60c is frozen or refrigerated, the temperature of the heated object 60c is lower than the table plate temperature Tt. In order to accurately recognize the object to be heated 60c, it is determined that the object to be heated 60c has been recognized when the lowest temperature of each detected pixel is lower than the table plate temperature Tt by a specific temperature. The size of the heated object 60c is determined by a collection of pixels indicating temperatures included in a pre-confirmed temperature range corresponding to the difference between the table plate temperature Tt and the minimum temperature from the lowest temperature. (For example, the shaded area in FIG. 9). Then, the lowest temperature is recognized as the temperature of the object to be heated 60c, and the detected temperature of the object to be heated 60c is corrected according to the emissivity of the object to be heated 60c and calculated as the initial temperature of the object to be heated 60c. The reason why the detected temperature is corrected according to the emissivity is that even if the temperature of the heated object 60c is the same, if the emissivity is different, the temperature measured by the infrared sensor 52 will be different, so it is necessary to correct the temperature according to the emissivity. This is because there is. Note that the emissivity of the heated object 60c can be specified according to a set menu.

On the other hand, if the heated object 60c is higher than the table plate temperature Tt, in order to accurately recognize the heated object 60c, the heated object 60c must be It is determined that the heated object 60c has been recognized. The size of the heated object 60c is a collection of pixels indicating temperatures included in a pre-confirmed temperature range corresponding to the difference between the maximum temperature and the table plate temperature Tt. It is recognized as the size of the object 60c. Then, the maximum temperature is recognized as the temperature of the object to be heated 60c, and the detected temperature of the object to be heated 60c is corrected according to the emissivity of the object to be heated 60c and calculated as the initial temperature of the object to be heated 60c.

Furthermore, when the object to be heated 60c is at room temperature, the table plate temperature Tt and the temperature of the object to be heated 60c are equal. Therefore, no specific temperature difference is required between the detected temperature of each pixel and the table plate temperature Tt. Therefore, if it is not determined to be on either side of the specific temperature difference assuming that the object to be heated 60c is frozen or refrigerated, or the temperature difference assuming that the object to be heated 60c is higher than the table plate temperature Tt, The entire area of the table plate temperature Tt is recognized as the object to be heated 60c. Then, by heating the object to be heated 60c, the temperature rises, and the temperature at the position where this rise exceeds a specific temperature is re-recognized as the detected temperature of the object to be heated 60c, and the pixels where the specific temperature has increased are collected. This is re-recognized as the size of the object to be heated 60c. Also in this case, the detected temperature of the object to be heated 60c is corrected according to the emissivity of the object to be heated 60c and calculated as the initial temperature of the object to be heated 60c.

<Flowchart of microwave heating control>
Next, microwave heating control by the heating cooker of this embodiment will be explained using the flowcharts of FIGS. 10 and 11.

This microwave heating control mainly determines the table plate temperature Tt in the first stage flowchart shown in FIG. 10, and mainly determines the microwave heating mode in the second stage flowchart shown in FIG.

First, in step S1 in FIG. 10, the user opens the door 2 of the heating chamber 28, places the container 60 containing the object to be heated 60c on the table plate 24, and then closes the door 2. Then, the user selects the auto menu using the input section 71.

Next, in step S2, the user uses the input unit 71 to adjust the finish of the cooking. Specifically, one of "strong", "slightly strong", "medium", "slightly weak", and "weak" is selected from the finish adjustment K prepared in advance. Here, "medium" of the finishing adjustment K means finishing at a standard temperature, "strong" means finishing at a higher finishing temperature, and "weak" means finishing at a lower finishing temperature.

In step S3, the user presses the start button on the input unit 71.

In step S4, the weight sensor 25 detects the total weight W of the object to be heated 60c and the container 60 placed on the table plate 24.

In step S5, the internal temperature sensor 80 detects the internal temperature Ti.

In step S6, the control unit 23a determines whether the internal temperature Ti is higher than a predetermined temperature. When the internal temperature Ti is higher than the predetermined temperature, the internal high temperature mode is entered and the object to be heated 60c is heated. On the other hand, if not, the process proceeds to step S7.

Here, the internal high temperature mode means that when the temperature of the heating chamber 28 is high, such as immediately after oven cooking, the infrared sensor 52 cannot accurately detect the temperature of the object to be heated 60c, so the infrared sensor 52 cannot be used. This mode allows you to heat in the microwave without heating. Therefore, in this mode, the user selects whether the storage state of the heated object 60c is room temperature/refrigerated or frozen using the input unit 71, and based on this selection result and the detected weight W, the heated object 60c is exposed to the input temperature. The total heating time is calculated based on the result of confirming in advance the heating time enough to heat the heating object 60c, and the heating is performed.

In step S7, the infrared sensor 52 detects the back side temperature Tb and front side temperature Tf of the top surface of the table plate (see FIG. 9), and the outside temperature sensor 100 detects the outside temperature To of the outside of the heating chamber 28. .

In step S8, the control unit 23a compares the temperature difference between the back side temperature Tb and the outside temperature To, and the temperature difference between the front side temperature Tf and the outside temperature To, and if the former temperature difference is small, the control section 23a advances to step S9. If the latter temperature difference is small, the process advances to step S10.

In step S9, the control unit 23a adopts the back side temperature Tb, which is closer to the outside temperature To, as the table plate temperature Tt.

On the other hand, in step S10, the control unit 23a adopts the near side temperature Tf, which is closer to the outside temperature To, as the table plate temperature Tt.

Next, in step S11 of FIG. 11, the control unit 23a determines the placement area of the object to be heated 60c based on the temperature of each pixel on the top surface of the table plate. Through this step, a placement area for the object to be heated 60c as illustrated by the hatched area in FIG. 9 is specified.

In step S12, the control unit 23a determines whether the table plate temperature Tt adopted in step S9 or step S10 is higher than a predetermined temperature. If the table plate temperature Tt is high, the process proceeds to step S16; otherwise, the process proceeds to step S13. Note that if the table plate temperature Tt is determined to be high in this step, it is assumed that the table plate temperature Tt is high as a result of another microwave cooking being executed immediately before the current microwave cooking. I can do it.

In step S13, the control unit 23a determines whether the IGBT temperature detected by the IGBT temperature sensor 101 is higher than a predetermined temperature. If the IGBT temperature is high, the process proceeds to step S14; otherwise, the process proceeds to step S15. Note that if the IGBT temperature is determined to be high in this step, the IGBT that supplies power to the microwave heating section 330 has become high temperature as a result of another microwave cooking being executed immediately before the current microwave heating. It can be estimated that

In step S14, the control unit 23a determines whether the maximum temperature among the temperatures of each pixel on the top surface of the table plate measured by the infrared sensor 52 is higher than the temperature obtained by adding a predetermined temperature to the outside temperature To. . If the maximum temperature is high, the process proceeds to step S16; otherwise, the process proceeds to step S15. In addition, if it is determined that the top surface of the table plate is locally high temperature in this process, as a result of another microwave cooking being executed immediately before the current microwave cooking, the table plate may be affected by the heat of the previously heated object. It can be inferred that the upper surface is locally hot.

In step S15, the control unit 23a detects the initial temperature Ts of the heated object 60c based on the temperature measured by the infrared sensor 52 at the pixel determined to be the heated object region in step S11, and detects the initial temperature Ts of the heated object 60c based on the initial temperature Ts. The storage state of the object to be heated 60c is classified as frozen, refrigerated, or room temperature. Thereafter, depending on the state of the classified object to be heated 60c, cooking is performed in the normal heating mode. Note that the normal heating mode is a heating mode that is selected when the temperature of the object to be heated 60c can be detected correctly by the infrared sensor 52, and similarly to conventional heating control, the temperature of the object to be heated 60c is adjusted to the desired level for cooking. Heating ends when the end temperature is reached.

In step S16, the control unit 23a detects the initial temperature Ts of the heated object 60c based on the temperature measured by the infrared sensor 52 at the pixel determined to be the heated object region in step S11, and detects the initial temperature Ts of the heated object 60c based on the initial temperature Ts. Then, the storage state of the heated object 60c is classified as either frozen or non-frozen. Thereafter, depending on the state of the classified object to be heated 60c, cooking is performed in the placement location high temperature mode.

Placement location high temperature mode indicates that there is evidence that another item was being microwaved immediately before this microwave cooking (the back or front side of the table plate is high temperature, or the table plate is locally high temperature). ), if there is a possibility that the infrared sensor 52 misunderstands the temperature of the heated object 60c due to the trace, the heated object 60c is This heating mode calculates and heats the microwave heating time long enough to heat the object 60c to an appropriate temperature.

Here, microwave heating when the placement location high temperature mode is selected will be described using FIG. 13. The total heating time when the placement location high temperature mode is selected is the sum of the preceding sensing time t1 and the subsequent microwave heating time t2. The preceding sensing time t1 is a period for performing sensing processing, and the weight W and storage state of the object to be heated 60c are determined. On the other hand, the subsequent microwave heating time t2 is calculated using one of the following formulas based on the weight W of the object to be heated 60c determined by sensing and the storage state.

<When the object to be heated is frozen>
t2a= _k1 ×( _k2 - _k3 ×Ts)×W...(Formula 1)
<If the object to be heated is other than frozen (refrigerated, room temperature)>
t2b= _k1 ×( _k4 - _k5 ×Ts)×W...(Formula 2)
Here, _k1 is a coefficient depending on the finish adjustment K setting, for example, 1.5 for "strong" setting, 1.2 for "slightly strong" setting, and 1.2 for "medium" setting. is 1, 0.8 for the "slightly weak" setting, and 0.5 for the "weak" setting. Further, k ₂ to k ₅ are predetermined positive numbers, and values are set such that t2a in equation 1 and t2b in equation 2 are always positive values when the initial temperature Ts of the heated object is below the cooking completion temperature. be done.

As a result, as long as the storage state of the heated object 60c can be classified as frozen or other than frozen, even if the temperature of the heated object 60c cannot be accurately measured due to traces of previous microwave heating, the heated object 60c can be classified as frozen or other than frozen. The microwave heating time t2 required to heat the object 60c to an appropriate temperature can be calculated, and by using the microwave heating time t2, the object to be heated 60c can be heated to an appropriate temperature.

As explained above, according to the high-frequency heating cooker of this embodiment, when a plurality of objects to be heated are heated and cooked in succession, the temperature of the place where the objects to be heated, etc. are placed increases during the previous heating. Even if the current object to be heated can be installed, the installation location of the current object to be heated can be specified, and the current object to be heated can be heated to an appropriate temperature.

DESCRIPTION OF SYMBOLS 1... Main body of heating cooker, 23a... Control unit, 24... Table plate, 25... Weight sensor, 28... Heating chamber, 33... Magnetron, 52... Infrared sensor, 60... Container, 60c... To be heated, 71... Input Part, 80... Inside temperature sensor, 100... Outside temperature sensor, 101... IGBT temperature sensor, Ti... Inside temperature, To... Outside temperature, Tt... Table plate temperature, Tf... Near side temperature of table plate, Tb ...Temperature on the back side of the table plate, Ts...Initial temperature of the heated object

Claims

A heating chamber that houses the table plate,
a microwave heating section that heats the object placed on the table plate;
an infrared sensor that detects temperatures at multiple locations on the top surface of the table plate;
an outside temperature sensor that detects the outside temperature of the heating chamber;
A control unit that controls the microwave heating unit based on the temperature detected by the infrared sensor,
The control section is
Calculating the temperature difference between the temperature outside the refrigerator and the temperature on the back side of the table plate, and the temperature difference between the temperature outside the refrigerator and the temperature on the front side of the table plate,
If the former temperature difference is small, the back side temperature is adopted as the table plate temperature,
If the latter temperature difference is small, use the front side temperature as the table plate temperature,
A high-frequency heating cooking device characterized in that a region on the upper surface of the table plate that has a temperature difference from the table plate temperature is determined to be a mounting region for the object to be heated.
In the high frequency heating cooker according to claim 1,
The control unit, when the table plate temperature is higher than a predetermined temperature,
It is characterized by classifying whether the preservation state is frozen based on the initial temperature of the object to be heated detected by the infrared sensor, calculating the heating time according to the preservation state, and controlling the microwave heating section. High frequency heating cooker.
In the high frequency heating cooker according to claim 1,
Furthermore, it includes an IGBT temperature sensor that detects the IGBT temperature of the microwave heating section,
When the table plate temperature is not higher than a predetermined temperature, the control unit
When the IGBT temperature is higher than a predetermined temperature, and the maximum temperature among the temperatures of the upper surface of the table plate detected by the infrared sensor is higher than the predetermined temperature,
It is characterized by classifying whether the preservation state is frozen based on the initial temperature of the object to be heated detected by the infrared sensor, calculating the heating time according to the preservation state, and controlling the microwave heating section. High frequency heating cooker.
In the high frequency heating cooker according to claim 2 or 3,
Furthermore, it includes a weight sensor that detects the weight of the object to be heated,
The high-frequency cooking device is characterized in that the control section calculates a heating time according to the weight and controls the microwave heating section.