WO2015141208A1

WO2015141208A1 - High-frequency heating device

Info

Publication number: WO2015141208A1
Application number: PCT/JP2015/001436
Authority: WO
Inventors: 威彦安藤; 木下　学
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2014-03-18
Filing date: 2015-03-16
Publication date: 2015-09-24
Also published as: JPWO2015141208A1; JP6467645B2

Abstract

When the start of a heating operation is indicated by an operation unit, if the in-chamber temperature detected by a second temperature detection unit is greater than or equal to a prescribed temperature, a control unit in this high-frequency heating device determines the detected temperature to be a high temperature. During heating operations in which a high temperature has been determined, the control unit determines, as a placement position in which an object to be heated is placed, those of the sections detected by a first temperature detection unit which have a temperature at least a prescribed value lower than the temperature of the periphery of the temperature detection region. The control unit controls to perform a heating operation on the determined placement position. Thus, this simple configuration enables controlling heating of an object to be heated while accurately determining the position and temperature of the object to be heated.

Description

High frequency heating device

The present disclosure relates to a high-frequency heating device, particularly a microwave oven that cooks by microwave heating.

Since the object to be heated can be heated from the inside by microwave heating, the microwave oven is used in various applications such as reheating cooked foods and thawing frozen foods.

In some conventional microwave ovens, in addition to microwave heating, oven heating (Oven 加熱 heating), grill heating (Grill heating), and heating using steam in addition to these are performed.

Oven heating is a cooking method in which an object to be heated is heated using a grill heater and a convection heater. Grill heating is a cooking method in which an object to be heated is heated using a grill pan coated with a material that generates heat when irradiated with microwaves, and heat generated by the grill pan irradiated with microwaves.

In such a microwave oven having a plurality of functions, the heating chamber becomes high temperature (for example, 150 ° C.) after completion of oven heating or grill heating. Therefore, even if an attempt is made to automatically warm a food to a desired temperature by microwave heating immediately after oven heating or the like, the temperature sensor such as an infrared sensor cannot accurately detect the temperature of the food because the heating chamber is hot. Therefore, heating cannot be completed at a desired temperature.

In order to solve this problem, there has been proposed a cooker that uses the latent heat of evaporation to quickly cool the heating chamber when the heating chamber is hot (see, for example, Patent Document 1). This cooker emits mist into the heating chamber and decompresses the heating chamber to cause evaporation of the mist.

According to the cooker of Patent Document 1, the temperature of the food can be detected more accurately by lowering the temperature in the heating chamber.

JP 2009-109027 A

However, the cooker of Patent Document 1 requires a complicated configuration having a mist generator and a decompressor. Therefore, there is still room for improvement in controlling the heating of the object to be heated while accurately detecting the temperature and position of the object to be heated with a simple configuration.

The present disclosure solves the above-described conventional problem, and even when the start of microwave heating is instructed when the heating chamber is at a high temperature, the heating target is accurately determined and the position of the heating target is accurately determined. An object of the present invention is to provide a high-frequency heating device capable of heating an object.

The high-frequency heating device of one aspect according to the present disclosure includes a heating chamber, an operation unit, a high-frequency generation unit, a first temperature detection unit, a second temperature detection unit, and a control unit. The heating chamber accommodates an object to be heated. The operation unit is used to instruct the start of a predetermined heating sequence. The high frequency generator generates a microwave supplied to the heating chamber.

The first temperature detection unit has a plurality of infrared detection elements, and detects the temperature for each section by associating the plurality of infrared detection elements with the plurality of sections constituting the temperature detection region in the heating chamber. The second temperature detection unit detects the internal temperature of the heating chamber. The control unit controls the high frequency generation unit to execute the heating sequence based on the temperature information detected by the first and second temperature detection units.

Particularly, when the start of the heating sequence is instructed by the operation unit, the control unit determines that the internal temperature is higher than the predetermined temperature. A control part determines the division in which the temperature lower than the temperature of the peripheral part of a temperature detection area | region more than 1st predetermined value was detected as the mounting position of a to-be-heated object in the said heating sequence at the time of determining with high temperature.

According to the high-frequency heating device of the present disclosure, even if the start of microwave heating is instructed when the heating chamber is at a high temperature, the heating of the object to be heated can be performed with a simple configuration while accurately determining the position of the object to be heated. Can be controlled.

FIG. 1 is a perspective view illustrating a microwave oven according to an embodiment of the present disclosure. FIG. 2 is a perspective view showing the microwave oven shown in FIG. 1 with the door opened. FIG. 3 is a block diagram showing a main configuration for microwave heating in the microwave oven according to the present embodiment. FIG. 4 is a front view showing the microwave oven according to the present embodiment with the door opened. FIG. 5 is a side view showing the microwave oven according to the present embodiment with the door opened. FIG. 6 is a plan view showing a temperature detection region on the bottom surface of the heating chamber in the microwave oven according to the present embodiment. FIG. 7 is a flowchart of the warming operation in the microwave oven according to the present embodiment. FIG. 8 is a diagram showing a sequence (Sequence) of a warming operation in the microwave oven according to the present embodiment. FIG. 9 is a diagram illustrating an example of a temperature detection result used for mounting position determination.

The high-frequency heating device according to the first aspect of the present disclosure includes a heating chamber, an operation unit, a high-frequency generation unit, a first temperature detection unit, a second temperature detection unit, and a control unit. The heating chamber accommodates an object to be heated. The operation unit is used to instruct the start of a predetermined heating sequence (for example, a warming operation in the present disclosure). The high frequency generator generates a microwave supplied to the heating chamber.

Particularly, when the start of the heating sequence is instructed by the operation unit, the control unit determines that the internal temperature is high if it is equal to or higher than a predetermined temperature. In the warming operation when it is determined that the temperature is high, the control unit determines, as the placement position of the object to be heated, a section in which a temperature lower than the temperature of the peripheral portion of the temperature detection region by a first predetermined value or more is detected.

According to this aspect, when the heating operation is started when the heating chamber is at a high temperature, the object to be heated is placed in a section where a temperature lower than the first predetermined value than the temperature of the section located in the peripheral portion is detected. It is determined that it is placed.

Thereby, even if the heating chamber is hot, the object to be heated can be heated while accurately determining the mounting position. Since the mist generating mechanism and the pressure reducing mechanism are unnecessary, the heating of the object to be heated can be controlled with a simple configuration.

The high-frequency heating device according to the second aspect of the present disclosure is that, in the first aspect, a plurality of infrared detection elements are two-dimensionally arranged, and simultaneously detect and output temperatures in a plurality of sections. According to this aspect, the temperature of the compartment in the heating chamber can be detected more accurately, and the heating control by the heating sequence when the inside temperature is determined to be high can be performed with higher accuracy.

The high-frequency heating device according to the third aspect of the present disclosure is the first or second aspect, in which the control unit determines the heating time in the warming operation when the internal temperature is determined to be high according to the internal temperature. Control. According to this aspect, by controlling the heating time in consideration of the internal temperature, the heating control by the heating sequence when the internal temperature is determined to be high can be performed with higher accuracy.

The high-frequency heating device according to the fourth aspect of the present disclosure is that, in the third aspect, the control unit shortens the heating time when the internal temperature is high, and lengthens the heating time when the internal temperature is low. Control to do. According to this aspect, the temperature of the object to be heated after heating can be brought close to the target temperature by reversing the level of the internal temperature and the length of the heating time.

In any one of the first to fourth aspects, the high-frequency heating device according to the fifth aspect of the present disclosure is the first temperature detection unit in the heating sequence when the controller determines that the internal temperature is high. The heating time in the heating sequence is controlled on the basis of the temperature change of the mounting position detected by. According to this aspect, the heating control can be performed with higher accuracy by controlling the heating time in consideration of the temperature change of the mounting position.

In the high-frequency heating device according to the sixth aspect of the present disclosure, in the fifth aspect, when the control unit determines that the internal temperature is high, the first temperature detection unit detects the heating time in the heating sequence. The time point when the temperature rise value at the mounting position becomes equal to or greater than the second predetermined value is determined as a reference. According to this aspect, the temperature of the object to be heated can be controlled with higher accuracy by controlling the heating time in consideration of the temperature rise value of the placement position.

The high-frequency heating device according to a seventh aspect of the present disclosure is the sixth aspect, in which the control unit lowers the second predetermined value when the internal temperature is high and decreases the second predetermined value when the internal temperature is low. Control is performed to increase the predetermined value of 2. According to this aspect, the temperature of the article to be heated after heating can be brought close to the target temperature by setting the inside temperature high and low and the second predetermined value high and low.

In any one of the first to seventh aspects, the high-frequency heating device according to the eighth aspect of the present disclosure is based on the temperature of the section in the heating sequence when the controller determines that the internal temperature is high. The heating time in the heating sequence is controlled according to the determination result of whether or not the object to be heated is frozen. According to this aspect, it is possible to accurately perform heating control while accurately determining whether or not it is frozen.

In the eighth aspect, the high-frequency heating device according to the ninth aspect of the present disclosure is such that, in the eighth aspect, the control unit compares the lowest temperature detected with the temperature of the peripheral portion of the temperature detection region, thereby It is determined whether or not it is frozen. While the lowest temperature detected is likely to change depending on whether or not the object to be heated is frozen, the temperature at the peripheral portion of the temperature detection region is unlikely to change even if the object to be heated is frozen. According to this aspect, it can be determined more accurately whether or not it is frozen.

A high-frequency heating device according to a tenth aspect of the present disclosure, in any one of the first to ninth aspects, further includes a grill heater that heats the heating chamber, and the control unit determines that the internal temperature is high. In this case, the high frequency generator is controlled so as not to generate microwaves until a predetermined time has elapsed from the start of the heating sequence.

According to this aspect, the microwave is supplied after the predetermined time has elapsed from the start of the warming operation, so that the microwave is supplied to the grill heater whose temperature is higher than when the microwave is supplied immediately. Can be prevented, and the reliability of the grill heater can be improved.

Hereinafter, a microwave oven that performs microwave heating as an embodiment of the high-frequency heating device of the present disclosure will be described with reference to the accompanying drawings.

Note that the high-frequency heating device of the present disclosure is not limited to the configuration of the microwave oven described in the following embodiments. The high-frequency heating device of the present disclosure includes a heating device configured based on a technical idea equivalent to the technical idea described in the following embodiments, for example, a configuration having a function of only microwave heating. It includes a heating device having a heating function such as heat, convection, radiation, and steam.

FIG. 1 is a perspective view showing a microwave oven 20 according to an embodiment of the present disclosure. FIG. 2 is a perspective view showing a state where the door of the microwave oven 20 shown in FIG. 1 is opened. The microwave oven 20 according to the embodiment has a function of cooking food that is an object to be heated by a heating method such as heat transfer, convection, and radiation, in addition to microwave heating using a microwave.

As shown in FIGS. 1 and 2, the microwave oven 20 includes a main body 1 including a heating chamber 5 on which an object to be heated is placed, and a door 2 for opening and closing an opening on the front side of the heating chamber 5. I have. A handle 3 that is used when the door 2 is opened and closed is provided on the front upper portion of the door 2.

On the front surface of the door 2, there is provided an operation unit 4 including a touch screen for displaying various information and inputting a user instruction, a start button for instructing the start of cooking, and the like. When the user operates the touch screen in the operation unit 4 to input cooking conditions and the like and finally operates the start button, the microwave oven 20 starts various heating sequences.

FIG. 3 is a block diagram showing a main configuration for microwave heating in the microwave oven 20. As shown in FIG. 3, the microwave oven 20 includes an operation unit 4, a control unit 10, a magnetron 11, a waveguide 12, and a temperature detection unit 13.

The user inputs information such as cooking conditions through the operation unit 4. The magnetron 11 is a high frequency generator that generates microwaves. The waveguide 12 is provided below the bottom surface of the heating chamber 5 and guides the microwave generated by the magnetron 11 to a rotating antenna (not shown). The rotating antenna is provided below the center of the bottom of the heating chamber 5 and supplies microwaves into the heating chamber 5 while rotating the antenna having directivity.

The microwave oven 20 according to the present embodiment supplies uniform microwaves (Omnidirectionally uniform 供給する heating) for uniformly supplying microwaves in all directions and intensively supplies microwaves in a desired direction according to the control method of the rotating antenna. Locally (intensive) heating can be performed.

The temperature detection unit 13 detects the temperature inside the heating chamber 5. The control unit 10 controls the magnetron 11 according to the information input by the operation unit 4 and the temperature information detected by the temperature detection unit 13.

In the embodiment, the temperature detection unit 13 includes a first temperature detection unit and a second temperature detection unit. As will be described later, the first temperature detection unit is an infrared sensor that detects the temperature of a temperature detection region 30 that is virtually provided on the bottom surface of the heating chamber 5.

The second temperature detection unit is a temperature sensor (for example, a thermistor (not shown)) that detects the atmospheric temperature in the heating chamber 5 (hereinafter referred to as the internal temperature).

The microwave oven 20 further includes a temperature sensor (for example, a thermistor (not shown)) for detecting the environmental temperature of the place where the infrared sensor is provided. The temperature information detected by the infrared sensor is calibrated according to the environmental temperature information. As described above, the control unit 10 obtains the internal temperature information, the temperature information of the temperature detection region 30, and the environmental temperature information from the temperature detection unit 13.

The control unit 10 obtains information such as cooking conditions input in the operation unit 4 from the operation unit 4, and controls and sets the magnetron 11 that generates microwaves according to the temperature information obtained from the temperature detection unit 13. The object to be heated is cooked according to the cooking conditions and the like.

The microwave generated by the magnetron 11 is supplied to the inside of the heating chamber 5 through the waveguide 12 and the rotating antenna, and the object to be heated is microwave-heated.

In the embodiment, the rotating antenna and the waveguide 12 are provided below the bottom surface. However, the present disclosure is not limited to this configuration, and may be disposed above the top surface of the heating chamber 5 or the like. A plurality of sets of magnetrons 11 and waveguides 12 may be provided.

A heating chamber 5 that accommodates an object to be heated inside the main body 1 is divided into five surfaces, that is, a left and right side surface, a top surface, a bottom surface, and a back surface, and a door 2 provided in an opening on the front surface side. . Hereinafter, in the present embodiment, the opening side of the heating chamber 5 is defined as the front side, the back side is defined as the back side, the top side is defined as the upper side, the bottom side is defined as the lower side, and the heating chamber 5 is viewed from the front side. The right side is defined as the right side, and the left side is defined as the left side.

The microwave oven 20 further includes a grill heater (not shown) for heating the inside of the heating chamber 5. The grill heater is installed, for example, on the top surface of the heating chamber 5.

The microwave oven 20 further includes a circulation fan for circulating air in the heating chamber 5 and a convection heater (not shown) for heating the air circulated by the circulation fan.

Both the circulation fan and the convection heater are provided on the back side of the inner surface of the heating chamber 5. The circulation fan has a function of sucking out air from the heating chamber 5 and sending out air toward the heating chamber 5 through a punching hole (not shown) formed in the inner surface of the heating chamber 5. Thereby, hot air is circulated in the heating chamber 5.

The microwave oven 20 is configured such that, in addition to microwave heating, an oven pan used for oven heating and a grill pan used for grill heating are used. In order to support the grill dish and the oven dish, the right and left sides of the heating chamber 5 are provided with a plurality of stages (three stages in the embodiment) of supporting projections extending horizontally in the front-rear direction. Yes. Thereby, the dish for mounting a to-be-heated material in the optimal position for cooking can be installed.

FIG. 4 is a front view showing the microwave oven 20 with the door 2 opened. FIG. 5 is a side view showing the microwave oven 20 according to the embodiment with the door 2 opened. FIG. 5 shows a state in which a part of the main body 1 is cut away so that the inside of the heating chamber 5 can be seen.

As shown in FIGS. 4 and 5, the infrared sensor 6 is provided outside the upper part of the right side surface of the heating chamber 5, and the visual field 35 of the infrared sensor 6 covers almost the entire bottom surface of the heating chamber 5. The infrared sensor 6 is composed of a total of 64 infrared detection elements arranged in a matrix of 8 rows and 8 columns.

FIG. 6 is a plan view of the bottom surface of the heating chamber 5. As shown in FIG. 6, almost the entire bottom surface of the heating chamber 5 corresponds to the temperature detection region 30. The temperature detection region 30 is a region where the temperature can be detected by the infrared sensor 6 included in the temperature detection unit 13.

As shown in FIGS. 4 and 5, when the infrared sensor 6 is operated, the direction of the lens of the infrared sensor 6 is set to a predetermined depression angle so that the visual field 35 shown by a broken line covers the entire temperature detection region 30. . In this state (hereinafter, referred to as a detectable state), the infrared sensor 6 detects temperature information of an object to be heated placed in the heating chamber 5 through an opening 5a formed in the upper part of the right side surface of the heating chamber 5. To do.

The temperature detection region 30 is composed of sections (Detection compartments) 31 arranged in a matrix of 8 rows and 8 columns. The temperature information of each section of the temperature detection region 30 can be detected by associating the 64 infrared detection elements constituting the infrared sensor 6 with each section.

That is, the microwave oven 20 is configured to be able to detect all temperatures for 64 sections at once.

As shown in FIG. 6, in the present embodiment, almost the entire bottom surface of the heating chamber 5 corresponds to the temperature detection region 30, but not limited to this, for example, only a part of the bottom surface of the heating chamber 5. May be the temperature detection region 30.

The infrared sensor 6 is configured to be able to move the field of view 35 in the vertical direction by changing the depression angle around a horizontal rotation axis. In this Embodiment, the infrared sensor 6 moves the visual field 35 according to cooking conditions.

For example, in a cooking condition in which the object to be heated placed on the bottom surface of the heating chamber 5 is heated by microwaves, the direction of the lens of the infrared sensor 6 is changed so that the entire bottom surface of the heating chamber 5 is the temperature detection region 30. Then, the visual field 35 is adjusted to the entire temperature detection region 30. Under cooking conditions in which grill heating is performed simultaneously with the use of the grill heater, the temperature detection region 30 is set on the grill pan installed at a predetermined height.

As described above, the infrared sensor 6 according to the embodiment can move the visual field 35 in the vertical direction inside the heating chamber 5 by moving the temperature detection region 30 in the vertical direction according to the cooking conditions.

When the temperature of the infrared sensor 6 is not detected, the lens of the infrared sensor 6 is configured to be in a state of being directly below (standby state). Thereby, it is possible to prevent dirt from adhering to the lens surface. When the infrared sensor 6 is in a standby state, the entire infrared sensor 6 is configured to be cooled by cooling air. Since the entire infrared sensor 6 is cooled in the standby state, accurate temperature detection is possible at the next temperature detection.

The cooling air for cooling the infrared sensor 6 uses cooling air for the magnetron 11 that generates microwaves, and is configured to be blown from below to the infrared sensor 6 by a cooling duct.

Note that, when the thermistor and the infrared sensor included in the temperature detection unit 13 detect an abnormal temperature, the control unit 10 is configured to stop the operation of the magnetron 11 instantaneously.

[Warming operation]
Next, in the microwave oven 20 configured as described above, a warming operation that is a heating sequence for automatically heating an object to be heated to a desired temperature will be described. As specific examples of the object to be heated suitable for the warming operation, cold rice, cooked side dishes, and the like are assumed.

Hereinafter, the warming operation in the configuration in which the output can be set in three stages (weak, medium, and strong) so that the temperature of the heated object after heating can be set according to the user's preference will be specifically described.

FIG. 7 is a flowchart showing the warming operation in the present embodiment. FIG. 8 is a heating sequence of the warming operation performed according to the flowchart of FIG. FIG. 8 shows the internal temperature of the heating chamber 5, the output of the microwave, the operation of the cooling fan, and the operation of the circulation fan. In the following description, all control, determination, calculation, and the like are performed by the control unit 10.

In the microwave oven 20, the warming operation is started when the user presses a predetermined button on the operation unit 4.

When the user instructs the start of the warming operation, first, the thermistor (second temperature detection unit) of the temperature detection unit 13 detects the internal temperature of the heating chamber 5. When the internal temperature is determined to be high, the main heating sequence is started (start of warming operation when the internal temperature is high).

It is assumed that the reason why the inside of the heating chamber 5 is hot is immediately after the end of the oven heating using the grill heater, the circulation fan, and the convection heater. In the present embodiment, the internal temperature is determined to be high when the internal temperature is 100 ° C. to 260 ° C. When the internal temperature is 100 ° C. or lower, a normal automatic warming sequence is executed instead of the main heating sequence, but the description thereof is omitted.

When the internal temperature exceeds 260 ° C., the operation unit 4 displays an error and notifies the user that “warming operation” cannot be performed. In addition, you may change suitably the range of the internal temperature of 100 to 260 degreeC according to the use etc. of a microwave oven.

When the heating sequence is started, the infrared sensor 6 is shifted to a detectable state in step S101. In this detectable state, the temperature of the lens of the infrared sensor 6 rises due to heat from the heating chamber 5.

Therefore, in step S102, a cooling fan (not shown) provided outside the heating chamber 5 is operated to cool the infrared sensor 6 in a detectable state. Since the infrared sensor 6 is in a standby state during oven heating before the start of the warming operation, the lens is cold and the substrate is hot.

In such a state, when the infrared sensor 6 is shifted to a detectable state, the lens suddenly becomes hot and the temperature difference between the lens and the substrate increases. In order to prevent this, the entire infrared sensor 6 including the lens and the substrate is cooled in step S102. Thereby, the temperature of a lens and a board | substrate can be made more uniform, and the temperature of a to-be-heated object can be detected more correctly.

In step S103, the circulation fan is stopped. Specifically, the rotational speed of the circulation fan is gradually reduced by gradually decreasing the supply of electric power to the circulation fan that was operating during the oven heating before the warming operation. In this embodiment, the circulation fan is controlled to stop after a predetermined time (for example, 10 seconds) has elapsed.

In step S104, a standby time (Twait time shown in FIG. 8) is provided. Specifically, during a predetermined waiting time, the magnetron 11 is stopped, the cooling fan is continuously operated, and the rotational speed of the circulation fan is gradually reduced to stop. In this embodiment, the Twait time is set to 30 seconds.

In this embodiment, the period from the start of the warming operation to the lapse of the standby time is referred to as a “pseudo cooking stage”. In the simulated cooking stage, the internal temperature that was initially high decreases, but in the area where the object to be heated is placed, heat is absorbed by the object to be heated, so the temperature is higher than in other areas. Drops faster.

In the present embodiment, the microwave output setting can be changed according to the finished temperature of the object to be heated until the first predetermined time (for example, 14 seconds) has elapsed in the simulated cooking stage. The result of the output setting is stored in the control unit 10.

The detection mask time described later is determined according to the output setting result. The detection mask time determines the minimum time of the microwave heating time performed after the simulated cooking stage. For example, when “weak” is set, the detection mask time may be shortened, and when “strong” is set, the detection mask time may be lengthened. For example, the detection mask time may be 46 seconds for “weak” setting, 52 seconds for medium setting, and 75 seconds for strong setting.

After the elapse of the standby time in step S104, the magnetron 11 starts to generate microwaves in step S105. The generated microwave is supplied into the heating chamber 5 via the waveguide 12 or the like, and the object to be heated in the heating chamber 5 is microwave-heated. In the present embodiment, the output of the magnetron 11 is set to 700 W, for example.

In step S106, temperature detection of the temperature detection region 30 is started. Specifically, the infrared sensor 6 that has been shifted to the detectable state starts temperature detection of the entire temperature detection region 30 (in the present embodiment, the entire bottom surface of the heating chamber 5) from the end of the simulated cooking stage. In the present embodiment, the temperature detection is performed every predetermined time, for example, every second from the end of the simulated cooking stage. These results are stored in the control unit 10.

As described above, the infrared sensor 6 is cooled by the cooling fan while the lens is directed to the heating chamber 5 in the simulated cooking stage, and the entire temperature (particularly, the lens temperature and the substrate temperature) is made uniform. The Therefore, the temperature detection of the temperature detection region 30 started from step S106 can be performed more accurately.

In step S107, the placement position is determined. Specifically, using the first temperature detection result in step S106, a point (placement position) where the placement of the object to be heated is estimated in the temperature detection region 30 in the heating chamber 5 is determined.

In this regard, an example of the first temperature detection result in step S106 is shown in FIG. In FIG. 9, the detected temperature of the section 31a located at the left front corner of the peripheral edge of the temperature detection region 30 (in this embodiment, the peripheral edge of the bottom surface of the heating chamber 5) is set as the reference temperature, The difference from this reference temperature is displayed.

In step S107, a section lower than the reference temperature by a predetermined value or more is determined as the placement position. In the example shown in FIG. 9, a section that is 8 degrees or more lower than the reference temperature is determined as the placement position (shaded display in FIG. 9). As a result, a total of 14 sections are determined as placement positions as sections that are 8 degrees or more lower than the reference temperature.

Generally, in a section where an object to be heated is placed, heat is absorbed by the object to be heated, so that the temperature tends to decrease. On the other hand, since the object to be heated is not placed so much at the peripheral part of the temperature detection region 30 (for example, the peripheral part in the heating chamber 5), the temperature change due to the object to be heated hardly occurs.

Using such characteristics, a section that is lower than the temperature at the peripheral edge of the temperature detection region 30 by a predetermined value or more is estimated as the placement position of the object to be heated. Thereby, the placement of the object to be heated can be accurately determined. In addition, the peripheral part of the temperature detection region 30 is a section (for example, a figure) located in a corner of the temperature detection region 30 (for example, in the vicinity of the corner of the bottom surface of the heating chamber 5) where an object to be heated is hardly placed. Section 31a) shown in FIG.

In step S107, when there is no section determined to be the placement position, the process proceeds to step S108. If there is one or more sections determined to be the placement position, the process proceeds to step S109. When the process proceeds to step S108, the step subsequent to step S109 is not performed, and the “warming” operation is terminated after a predetermined time has elapsed. In the present embodiment, the heating duration when the process proceeds to step S108 is set to the same time as the detection mask time (for example, 46 seconds) when the output setting is weak.

If there is one or more sections determined to be the mounting position, in step S109, it is determined whether the object to be heated is a small amount or a large amount (hereinafter, this determination is a small amount / large amount determination (Large / small amount judgment)). Called). Specifically, it is determined whether the object to be heated is a small amount or a large amount according to the number of sections determined as the mounting position determined in step S107.

More specifically, a threshold for determining whether the object to be heated is a small amount or a large amount is calculated by the following equation (1). When the number of sections determined to be the mounting position is equal to or greater than this threshold, the object to be heated is determined to be large, and otherwise the object to be heated is determined to be small.

Threshold value for small / large quantity determination = A × (internal temperature at start of warming operation) + B (1)
In the above equation (1), when calculating this threshold value, the internal temperature of the heating chamber 5 at the start of the warming operation is used. In the above formula (1), A and B are constants. The values of A and B can be appropriately set according to the specifications of the microwave oven.

In this embodiment, for example, A is set to 0.1, B is set to 16, and the internal temperature at the start of the warming operation is set to 150 ° C. In this case, the threshold value is “31”. When this threshold value is used, as shown in FIG. 9, when there are 14 sections determined to be placement positions, the number of sections determined to be placement positions is smaller than the threshold value (31). Is determined to be “small”. The result of determination in step S109 is stored in the control unit 10.

A standby time is provided in step S110. Specifically, the process waits for a predetermined time (T1stscan time shown in FIG. 8) while continuously performing the microwave supply in step S105 and the temperature detection for the temperature detection region 30 in step S106 every predetermined time.

Thus, the temperature change in the heating chamber 5 is observed every predetermined time while the object to be heated in the heating chamber 5 is heated by the microwave. In the present embodiment, the T1stscan time is set to 30 seconds.

When the standby time has elapsed, in step S111, the object to be heated is frozen / normal temperature judgment (Frozen / Normal Judgment). Specifically, it is determined whether the object to be heated is frozen based on the temperature of each section. More specifically, the temperature for refrigeration / room temperature determination is calculated by the following equation (2), and this temperature is compared with the lowest temperature in the temperature detection region 30, so that the object to be heated is frozen. It is determined whether or not it has been done.

Temperature for freezing / normal temperature determination = C × (plate temperature) + D (2)
Here, C and D in the above formula (2) are constants. In the above formula (2), the “plate temperature” is the temperature of the section located at the peripheral edge of the temperature detection region 30 at the time when the standby time in step S110 has elapsed. As the reference temperature for the freezing / normal temperature determination in step S111, the temperature of the section 31a is used as in the case of step S107.

In the present embodiment, C is set to 0.64, D is set to 8, and the plate temperature is set to 80 ° C. In this case, the temperature for freezing / normal temperature determination is 59.2 ° C. On the basis of this temperature, when the lowest temperature among the temperatures of each compartment is 59.2 ° C. or higher, it is determined as normal temperature, and when it is lower than 59.2 ° C., it is determined as frozen.

The result of freezing / room temperature determination is sent to the control unit 10 and stored therein. If it is determined that the temperature is normal, the process proceeds to step S112. If it is determined that the temperature is frozen, the process proceeds to step S115.

In step S112 and step S115, a time limit (Time limit: TL) is determined according to the result of the freezing / room temperature determination in step S111. TL is the maximum time for continuously detecting the temperature rise value in steps S113 and S117, which will be described later, after steps S105 and S106 at the end of the pseudo cooking stage.

In the present embodiment, TL is determined in consideration of the above-described small / large determination and output setting in addition to the result of freezing / normal temperature. An exemplary value of TL may be set to about 80 seconds for room temperature and about 140 seconds for freezing.

In addition, after moving to step S115 and determining TL at the time of refrigeration determination, refrigeration / normal temperature determination is performed again at step S116. Although this step S116 is determined to be frozen in step S111, the freezing / normal temperature determination is performed again based on the subsequent temperature change. Thereby, the precision of freezing / normal temperature determination can be improved. Specifically, when the following formula (3) is satisfied, it is determined that the temperature is normal.

ΔT1 ≧ E × (internal temperature at the start of warming operation) + F (3)
In the above formula (3), ΔT1 is a temperature rise value of the lowest temperature among the temperatures detected by the infrared sensor 6 after the end of the pseudo cooking stage. In the present embodiment, the temperature rise value from 10 seconds to 50 seconds after the end of the pseudo cooking stage is assumed to be ΔT1, for example.

However, the period of ΔT1 may be set as appropriate according to the specifications of the microwave oven, and may be set variably according to the output setting, for example. In the above formula (3), E and F are constants. The constants E and F may also be set as appropriate.

If it is determined in step S116 that the temperature is normal, the process proceeds to step S112. If it is not determined that the temperature is normal, the process proceeds to step S117 while maintaining the refrigeration determination.

Next, in step S113 and step S117, a temperature rise value is detected. Specifically, it is determined whether or not the temperature rise value at the placement position is equal to or greater than a predetermined value (ΔT2), using the temperature at the end of the pseudo cooking stage as the reference temperature (T1stscan time). More specifically, the control unit 10 determines that a predetermined temperature increase value has been detected when the temperature increase value at at least one point among the plurality of placement positions is equal to or greater than ΔT2.

In this embodiment, ΔT2 is determined according to the determination result of freezing / normal temperature, the internal temperature at the start of the warming operation, the output setting, and the like. Specifically, ΔT2 is decreased as the room temperature is determined to be higher, the temperature inside the chamber is higher, and the output setting is weaker. An exemplary value of ΔT2 may be set to about 21 ° C. at normal temperature and about 25 ° C. for freezing.

The value of ΔT2 may be set as appropriate. For example, ΔT2 in step S113 and step S117 may include the same value. Note that the T1stscan time, which is the timing for acquiring the reference temperature, may be controlled to be variable according to the level of the internal temperature detected by the thermistor, for example.

If a temperature rise value of ΔT2 or more is detected in step S113 and step S117, the process proceeds to step S119. If the temperature rise value is not detected, the process proceeds to step S114 and step S118, respectively.

In step S114 and step S118, time limit determination is performed. Specifically, it is determined whether or not the TL determined in step S112 and step S115 has elapsed since the end of the pseudo cooking stage.

If it is determined that the TL has not elapsed, the process returns to step S113 and step S117, and the temperature rise value is detected again. Thereafter, each step is repeated every predetermined time, for example, every second until the result of either the temperature rise value detection in step S113 and step S117 and the time limit determination in step S114 and step S118 becomes YES.

On the other hand, if it is determined in step S114 and step S118 that TL has elapsed, the process proceeds to step S119. Note that the sequence of FIG. 8 shows a case where a temperature rise value of a predetermined value or more is detected in step S113 or step S117 when the Tc time has elapsed from the end of the pseudo cooking stage before reaching TL. .

In the present embodiment, a period from the end of the pseudo cooking stage to the detection of the temperature rise value or the detection of the time limit is referred to as “P1 stage”.

When the P1 stage is completed, an additional heating time Tp2 is determined in step S119. Specifically, the time (Tp2) for continuing microwave heating from the end of the P1 stage is determined. In the present embodiment, when Tp2 is determined, it is determined according to the three parameters of the determination result of refrigeration / normal temperature, the determination result of small amount / large amount, and the output setting. An exemplary value of Tp2 may be set as about 20 seconds, for example.

In step S120, the operation of the circulation fan is resumed. Specifically, the operation of the circulation fan that has been stopped between the P1 stage from the middle of the pseudo cooking stage is resumed. Thereby, while the object to be heated is additionally heated by the microwave, the air in the heating chamber 5 is circulated by operating the circulation fan, and the temperature in the heating chamber 5 becomes more uniform.

In this embodiment, the output of the magnetron 11 is controlled to be lowered simultaneously with the resumption of the operation of the circulation fan (for example, from 700 W to 300 W). After step S120, the warming operation ends.

In this embodiment, a period from the end of the P1 stage to the end of the warming operation is referred to as “P2 stage”. In the present embodiment, the operation of the circulation fan is resumed when the P1 stage is shifted to the P2 stage, but the circulation fan may be set to be stopped. You may control to maintain the output of the magnetron 11 without reducing.

As described above, by performing the warming operation, the object to be heated can be heated to a predetermined temperature by microwaves and warmed. In the heating sequence shown in FIG. 8, the case where the microwave heating is performed until the time including the additional heating time has been described, but the heating may be terminated when the detection mask time described above has elapsed.

It should be noted that it is possible to appropriately set the case where the operation is temporarily stopped and then restarted by the user opening the door 2 during the warming operation.

In the present embodiment, when the door 2 is opened between the simulated cooking stage and the P1 stage and the warming operation is resumed, the process returns to the first step S101, and the heating sequence is controlled from the beginning.

When the door 2 is opened during the P2 stage and the warming operation is resumed, the operation is resumed from the time when the door 2 is opened. That is, the control unit 10 controls to digest the remaining time of the additional heating time set in step S119.

As described above, in the present embodiment, when the start of the warming operation is instructed by the operation unit 4, the internal temperature is determined to be high when the temperature is equal to or higher than a predetermined temperature (for example, 100 ° C.).

In the warming operation when it is determined that the temperature is high, the object to be heated is placed in a section where a temperature lower than the temperature of the peripheral portion of the temperature detection region 30 (reference temperature) by a first predetermined value (for example, 8 ° C.) is detected. It is determined that

The position is regarded as the placement position of the object to be heated, and local heating is performed in that direction. As described above, when the heating operation is started when the inside of the heating chamber 5 is at a high temperature, the temperature difference from the peripheral portion of the temperature detection region 30 that seems to have the smallest temperature change is equal to or greater than the first predetermined value. It is determined that the large section is a position where the object to be heated is placed.

Thereby, even if the inside of the heating chamber 5 is high temperature, it is possible to control the heating of the object to be heated while accurately determining the mounting position. According to the present embodiment, since a mist generation mechanism and a pressure reduction mechanism are not required, heating of an object to be heated can be controlled with a simple configuration.

In the present embodiment, the heating time in the warming operation when the internal temperature is determined to be high is controlled according to the internal temperature.

Specifically, depending on the internal temperature, the small / large quantity determination in step S109, the time limit determination in steps S112 and 115, the freezing / normal temperature determination in step S116, and the additional heating time in step S119 are determined. .

As described above, by controlling the heating time in consideration of the inside temperature, the warming operation at the time of high temperature determination can be controlled with higher accuracy. In particular, when the internal temperature is high, the heating time is set short, and when the internal temperature is low, the heating time is set long. In this way, the temperature of the object to be heated after heating can be brought close to the target temperature.

In the present embodiment, the heating time in the warming operation is controlled based on the temperature change of the placement position during the warming operation when the internal temperature is determined to be high. Specifically, when calculating ΔT2 used in detecting the temperature rise value in steps S113 and 117, the temperature change of the placement position is taken into consideration. Thus, heating control can be performed more accurately by controlling the heating time in consideration of the temperature change of the mounting position in the warming operation when the internal temperature is determined to be high.

In particular, the control unit 10 determines when the temperature rise value at the mounting position where the infrared sensor 6 detects the heating time in the warming operation becomes equal to or greater than a second predetermined value (ΔT2) (when the temperature rise value is detected). Decide on a standard. In this way, by controlling the heating time in consideration of the temperature rise value of the placement position, the temperature of the object to be heated can be controlled with higher accuracy.

In this embodiment, ΔT2 is set low when the internal temperature is high, and ΔT2 is set high when the internal temperature is low. In this way, the temperature of the object to be heated after heating can be brought close to the target temperature. Note that the reference temperature that serves as a reference for the temperature inside the chamber may be set as appropriate. For example, the reference temperature may be set in a plurality of tables depending on the determination result of freezing / normal temperature or the output setting. .

In the present embodiment, the control unit 10 determines whether or not the object to be heated is frozen based on the temperature detected by the infrared sensor 6 in the warming operation when the inside temperature is determined to be high (that is, whether it is frozen or not). It is normal temperature) and the heating time in the warming operation is controlled according to the result.

Specifically, in step S111, the temperature for freezing / room temperature determination used in the freezing / room temperature determination is calculated in consideration of the temperature (plate temperature) of the section located at the periphery of the temperature detection region 30. is doing. Thereby, it is possible to accurately determine whether or not it is frozen and to perform accurate heating control.

In particular, in step S111, it is determined whether or not the object to be heated is frozen by comparing the lowest temperature detected with the temperature of the peripheral edge of the temperature detection region 30. While the lowest temperature is likely to change depending on whether or not the object to be heated is frozen, the temperature at the peripheral portion of the temperature detection region is not easily changed even if the object to be heated is frozen. By comparing these two temperatures, it can be determined with higher accuracy whether or not it is frozen.

In the present embodiment, a grill heater for heating the inside of the heating chamber 5 is further provided, and the control unit 10 starts a warming operation when the inside temperature is determined to be high, and then starts a predetermined time (Twait time). During this time, the magnetron 11 is controlled so as not to generate microwaves.

By starting the supply of microwaves after a predetermined time has elapsed since the start of the warming operation, compared to the case where microwaves are supplied immediately, microwaves are radiated to the part where the temperature is high, and the temperature at that part is The so-called red spot phenomenon that rises abnormally can be suppressed, and the reliability of the apparatus can be improved.

In the present embodiment, the case where the infrared sensor 6 is shifted to the detectable state at the start of the simulated cooking stage has been described. However, the present invention is not limited to such a case. It may be.

It should be noted that, by appropriately combining arbitrary embodiments of the above-described various embodiments, the effects possessed by them can be produced.

The high-frequency heating device of the present disclosure can control the heating of the object to be heated while accurately determining the position and temperature of the object to be heated with a simple configuration. The high-frequency heating device of the present disclosure is useful in, for example, a home microwave oven.

DESCRIPTION OF SYMBOLS 1 Main body 2 Door 3 Handle 4 Operation part 5 Heating chamber 6 Infrared sensor 10 Control part 11 Magnetron 12 Waveguide 13 Temperature detection part 20 Microwave oven 31 Section 30 Temperature detection area 35 View field

Claims

A heating chamber for storing an object to be heated;
An operation unit for instructing the start of a predetermined heating sequence;
A high frequency generator for generating microwaves to be supplied to the heating chamber;
A first temperature detection unit having a plurality of infrared detection elements and detecting the temperature of the object to be heated;
A second temperature detection unit for detecting the internal temperature of the heating chamber;
Based on the temperature information detected by the first and second temperature detection units, a control unit that controls the high frequency generation unit to execute the heating sequence;
With
The first temperature detection unit detects the temperature for each of the sections by causing the plurality of infrared detection elements to correspond to the plurality of sections constituting the temperature detection region in the heating chamber,
The controller determines that the internal temperature is high if the internal temperature is equal to or higher than a predetermined temperature when the operation unit is instructed to start the heating sequence.
In the heating sequence in the case where the controller determines that the temperature is high, the position where the object to be heated is placed in the section in which the temperature lower than the temperature of the peripheral portion of the temperature detection region by a first predetermined value or more is detected. A high-frequency heating device configured to determine
The high-frequency heating device according to claim 1, wherein the plurality of infrared detection elements are two-dimensionally arranged and simultaneously detect and output temperatures in the plurality of sections.
The high-frequency heating device according to claim 1, wherein the control unit controls a heating time in the heating sequence when the internal temperature is determined to be high according to the internal temperature.
The high-frequency heating device according to claim 3, wherein the control unit controls the heating time to be shortened when the internal temperature is high and the heating time is lengthened when the internal temperature is low.
The said control part controls the heating time in the said heating sequence based on the temperature change of the said mounting position which the said 1st temperature detection part in the said heating sequence detects when the said internal temperature is high temperature. Item 2. The high-frequency heating device according to Item 1.
The controller is configured to detect a heating time in the heating sequence when the internal temperature is determined to be high as the first temperature detector detects a temperature rise value at the mounting position equal to or greater than a second predetermined value. The high-frequency heating device according to claim 5, wherein the high-frequency heating device is determined based on a point in time when
The said control part is controlled so that said 2nd predetermined value may be made low when the said internal temperature is high, and said 2nd predetermined value is made high when the said internal temperature is low. High frequency heating device.
The control unit determines whether the object to be heated is frozen based on the temperature of the section in the heating sequence when the internal temperature is determined to be high. The high frequency heating device according to claim 1, wherein the heating time is controlled.
The high frequency according to claim 8, wherein the control unit determines whether or not the object to be heated is frozen by comparing the lowest detected temperature with the temperature of the peripheral portion of the temperature detection region. Heating device.
A grill heater for heating the heating chamber;
2. The high frequency according to claim 1, wherein when the internal temperature is determined to be high, the control unit controls the high frequency generation unit so as not to generate a microwave until a predetermined time elapses from the start of the heating sequence. Heating device.