JP2001324147A - Microwave oven - Google Patents

Abstract

PROBLEM TO BE SOLVED: To utilize a food placement part entirely effectively and to control the heating of food accurately by equipping the food placement part that is nearly in the same shape as the horizontal section of a heating chamber. SOLUTION: A bottom plate 3 having nearly the same size as the horizontal section of a heating chamber 2 is provided at the lower portion in the heating chamber 2, and an infrared sensor 15 for detecting the temperature of food is configured so that it has a plurality of measurement visual fields over nearly the entire portion of the bottom plate 3. As a result, even if the food is placed at any site on the bottom plate 3, the temperature of the food can be detected accurately, thus utilizing the entire bottom plate 3 effectively and controlling heating accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave oven provided with a food placing portion having substantially the same shape as a horizontal section of a heating chamber.

[0002]

Conventionally, in a microwave oven, it has been generally practiced to prevent the occurrence of uneven heating by heating and cooking while rotating a turntable on which food is placed. However, when the food is placed on the turntable, the four corners of the substantially square heating chamber become dead spaces, so that the amount of food that can be stored is smaller than the size of the heating chamber. there were.

Therefore, a microwave oven has been proposed in which a tray having substantially the same shape as the horizontal section of the heating chamber is provided at the lower portion of the heating chamber to increase the amount of food to be stored. In this case, an excitation port is provided below the tray in the heating chamber, and a rotating waveguide for dispersing the microwave supplied to the excitation port is provided so that the food can be heated evenly.

However, in the case of the configuration in which microwaves are supplied from below the tray as described above, it is difficult to provide a weight sensor for detecting the weight of food on the tray.
Therefore, instead of a configuration in which heating is controlled based on the weight of the food, the temperature of the food is detected by an infrared sensor, and the heating is controlled based on the detection result. However, unlike the turntable, the tray does not move (does not rotate), so that if there is food at a position outside the measurement field of view of the infrared sensor, the temperature of the food cannot be detected. In particular, conventionally, a monocular infrared sensor is often used. However, with a monocular infrared sensor,
Since only a part of the temperature of the food can be detected, there is a problem that the heating cannot be accurately controlled.

[0005] In addition, when food is placed at a position outside the field of view of the infrared sensor, the temperature of the food cannot be detected. there were.

Accordingly, an object of the present invention is to provide an apparatus having a food placing section having substantially the same shape as the horizontal cross section of the heating chamber, whereby the entire food placing section can be used effectively, An object of the present invention is to provide a microwave oven capable of controlling heating with high accuracy.

[0007]

According to a first aspect of the present invention, there is provided a microwave oven provided in a heating chamber for accommodating food, a microwave generator for generating microwaves, and a chamber wall surrounding the heating chamber. Excitation port, a main waveguide that guides the microwave generated by the microwave generator to the excitation port, and a microwave dispersion unit that disperses the microwave guided to the excitation port and supplies the dispersed microwave into the heating chamber. A food mounting portion provided at a lower portion of the heating chamber and having substantially the same size as a horizontal cross section of the heating chamber, an infrared sensor for detecting the temperature of the food, and the infrared sensor based on a detection result of the infrared sensor. Heating control means for controlling heating of the food by the magnetron, wherein the infrared sensor is configured to have a plurality of measurement fields of view extending substantially over the entire upper surface of the placing section. Having.

[0008] According to the above configuration, the temperature of the food can be reliably detected regardless of the position of the food on the food mounting portion, so that the entire food mounting portion is effectively used. And heating can be controlled accurately.

In this case, it is preferable that the infrared sensor is configured by housing a plurality of infrared detecting elements in one case (the invention of claim 2). According to the above configuration, since only one infrared transmission window is provided on the chamber wall of the heating chamber corresponding to the infrared sensor, the amount of radio waves leaking from the heating chamber can be reduced. Further, the size of the infrared sensor can be reduced.

Further, m infrared sensors are arranged so that the number of the infrared sensors is m in the vertical direction and n in the horizontal direction of the food placing portion.
It is preferable to configure so as to have × n measurement fields of view (where m and n are integers) and to make the ratio between m and n approximately the same as the vertical and horizontal dimensional ratio of the food placing portion. (Invention of claim 3).

According to the above configuration, the overlap between adjacent measurement fields can be reduced, so that the output signal of the infrared sensor can be processed efficiently.

Further, the infrared sensor may be configured so that the sizes of a plurality of measurement visual fields in the food placing portion are substantially the same (the invention of claim 4). According to the above configuration, since the detection accuracy of each measurement visual field becomes the same, the temperature of the food can be detected with the same accuracy regardless of where the food is placed on the food mounting portion.

Further, it is preferable that the food placing section is constituted by a tray which is housed so as to be able to be taken in and out of the heating chamber (the invention of claim 5). According to the above configuration, it is easy to perform an operation of storing food in the heating chamber or taking out food from the heating chamber. Further, by taking out the tray from the heating chamber, the food placing section can be easily cleaned, and the entire food placing section can be washed, so that the food placing section can be kept clean. .

Further, it is preferable that a mark indicating the visual field of measurement of the infrared sensor is attached to the food placing portion (the invention of claim 6). According to the above configuration, it is used that substantially the entirety of the food placing portion is in the temperature detectable range, that is, the temperature can be detected even if the food is placed on any part of the food placing portion. Can be visually recognized.

Further, it is preferable that the apparatus further comprises control means for controlling the microwave dispersion means based on the detection result of the infrared sensor. In particular, the microwave dispersion means guides the microwave into the heating chamber in communication with the excitation port, and the rotating waveguide having an opening for supplying the microwave into the heating chamber; In the case where the control means comprises a driving means for driving the waveguide to rotate, it is preferable that the control means is configured to control the rotation / stop of the rotary waveguide (the invention of claim 8).

When the rotating waveguide is rotated, the position of the opening changes continuously, so that the microwaves are dispersed and supplied into the heating chamber, and as a result, the electric field distribution in the heating chamber becomes substantially uniform. On the other hand, when the rotating waveguide is stopped, a characteristic electric field distribution according to the position of the opening appears in the heating chamber. Therefore, based on the detection result of the infrared sensor, by rotating or stopping the rotating waveguide so that an electric field distribution suitable for the heating state of the food can be obtained, the food can be efficiently heated, In addition, uneven heating can be eliminated.

In this case, it is preferable that the excitation port is provided at the bottom of the heating chamber. According to the above configuration, since the distance between the excitation port and the food becomes short, the direct wave of the microwave greatly contributes to the heating of the food. For this reason, the heating can be controlled more easily than when the standing wave of the microwave greatly contributes to the heating of the food. That is,
By stopping the rotating waveguide at an appropriate position and bringing the opening of the rotating waveguide close to the low-temperature portion of the food, such as heating the low-temperature portion of the food intensively,
It is possible to perform efficient heating cooking.

Further, it is preferable that a display means for displaying a detection result in each measurement field of view of the infrared sensor is provided (the invention of claim 10). According to the above configuration, the user can grasp the heating state of the food, so that the cooking time, the heating time, and the like can be appropriately adjusted according to the heating state of the food.

Further, it is a good configuration to include a display means for displaying the control state of the microwave dispersion means (the invention of claim 11). According to the above configuration, the user can know how the food is heated.

In this case, it is preferable that the display means is constituted by a color full dot LCD (the invention of claim 12). According to the above configuration, since various screens can be switched and displayed, much information can be displayed even when the display range is limited. In addition, since the detection result of the infrared sensor and the control state of the microwave dispersion means can be expressed by different colors, it is easy to comprehend the contents even when displaying a lot of information.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention (corresponding to claims 1 to 3, 6 to 12) will be described below with reference to FIGS. First, FIG. 1 shows a longitudinal sectional front view of a microwave oven according to the present embodiment. Inside a cabinet 1, a heating chamber 2 having an open front is provided. The heating chamber 2 has a substantially square cross section in the horizontal direction.

In the lower part of the heating chamber 2, the heating chamber 2
A bottom plate 3 serving as a food placing portion is disposed so as to have a predetermined space between the bottom plate 2a and the bottom portion 2a. The bottom plate 3 has a substantially square shape that is the same as the horizontal cross-sectional shape of the heating chamber 2 and is made of heat-resistant glass or ceramic through which microwaves can pass. Although not shown, a door for opening and closing the front opening of the heating chamber 2 is rotatably mounted on the front surface of the cabinet 1.

A bottom portion 2 which is one of the chamber walls of the heating chamber 2
A rectangular excitation port 4 is formed at a substantially central portion of a. In this case, the four peripheral portions of the excitation port 4 are disposed so as to be parallel to the left and right walls, the rear wall, and the front surface (the front surface of a door (not shown)) of the heating chamber 2. ing. At this time, the opening width dimensions La and Lb of the excitation port 4 are set.
Are set to λ / 2 (λ is the wavelength of the microwave; λ = 12.24 cm in this embodiment) or more.

On the other hand, a magnetron 6 as a microwave generator is disposed in a machine room 5 provided on the right side of the heating chamber 2 in the cabinet 1. Also,
The bottom 2a of the heating chamber 2 in the cabinet 1
The main waveguide 7 is disposed below the lower part of the main waveguide 7. One end of the main waveguide 7 is connected to an antenna 6 a of the magnetron 6.
The other end is configured to communicate with the excitation port 4. At this time, as shown in FIG. 2, the main waveguide 7 is disposed so as to be parallel to the rear wall portion of the heating chamber 2, and the traveling direction of the microwave in the main waveguide 7 is The direction is indicated by an arrow M in FIG.

On the other hand, a rotating waveguide 8 is rotatably disposed in the space between the bottom surface 2a and the bottom plate 3 in the heating chamber 2. In addition, a motor 9 as a driving means is disposed below the excitation port 4 in the lower part of the cabinet 1. The rotating shaft 9a of the motor 9 is
The rotary waveguide 8 extends through the main waveguide 7 to the space between the bottom surface 2a and the bottom plate 3, and is connected to the tip of the rotary shaft 9a. In the present embodiment, the rotating waveguide 8 and the motor 9 constitute a microwave dispersion means.

As shown in FIGS. 3 and 4, the rotary waveguide 8 is formed by bending a metal plate, and has a rotation center 10 and a branch extending from the rotation center 10 in three directions. It is composed of sections 11-13. The branch portions 11 to 13
Side plate portions 11a to 13a are formed by bending downward. Further, projecting portions 11b to 13b are provided at lower end portions of the side plate portions 11a to 13a.

As shown in FIG. 1, a duct is formed by a combination of the rotating waveguide 8 and the bottom surface 2a of the heating chamber 2. At this time, each branch 1 of the rotating waveguide 8
Opening portions 11c to 13c are formed at the tips of 1 to 13, respectively. Each of the branch portions 11 to 13 of the rotating waveguide 8 has rectangular openings 11d to 13d.
In this case, the size of the openings 11d to 13d is configured to decrease in the order of the opening 11d, the opening 12d, and the opening 13d.

On the other hand, the motor 9 is composed of, for example, a brushless motor, and is configured to be able to rotate at a constant speed. As shown in FIG. 10, the motor 9 is provided with a position detecting device 14 for detecting the rotational position of the rotating waveguide 8. The position detecting device 14 includes the rotating shaft 9.
The motor 14 includes a subject 14a fixed to a mounting member 9b that rotates integrally with the motor 9a, and a photocoupler 14b fixed to a frame 9c of the motor 9.

The photocoupler 14b is connected to the subject 1
It is configured to output a detection signal in response to detecting the passage of 4a. In this embodiment, the photocoupler 14b is adjusted so as to output a detection signal when the branch portion 11 of the rotary waveguide 8 is located at the home position P0 (see FIG. 2). In this case, since the motor 9 is configured to rotate at a constant speed, the rotational position of the rotary waveguide 8 is detected based on the elapsed time after the photocoupler 14b outputs the detection signal. Can be.

Also, as shown in FIG.
A non-contact infrared sensor 15 is disposed in a substantially central portion of the upper portion of the heating chamber 2. A window 15a for infrared transmission is formed in the ceiling 2b of the heating chamber 2 corresponding to the infrared sensor 15. The infrared sensor 15 is, as shown in FIGS.
6 and a sensor circuit section 18 housed in a cylindrical sensor case 17. The sensor circuit section 18 includes a plurality of, for example, 16 infrared detecting elements (thermopiles) p1 to p16 on an IC chip 19, each having 4 rows × 4
They are arranged in columns.

The measurement field of view of the infrared sensor 15 is 16
It is an aggregate of the measurement visual fields formed by the individual infrared detection elements p1 to p16. In this embodiment, it is configured to cover substantially the entire area on the bottom plate 3 of the heating chamber 2.
At this time, as shown in FIG. 7, on the bottom plate 3 of the heating chamber 2, marks m1 to m16 representing the measurement visual fields formed by the individual infrared detection elements p1 to p16 are drawn.

In the present embodiment, the ratio between the number m of arrangements in the vertical direction and the number n of arrangements in the horizontal direction of the measurement visual field is 4: 4.
= 1: 1. This is set based on the fact that the ratio between the vertical dimension (length dimension in the front-rear direction) and the horizontal dimension (length dimension in the left-right direction) of the bottom plate 3 is approximately 1: 1. By arranging the measurement fields in this way,
Overlap between adjacent measurement fields can be reduced. Therefore, the portion of the bottom plate 3 that is included in the overlap of the plurality of measurement visual fields is reduced, so that the processing of the detection signal of the infrared sensor 15 can be performed efficiently.

FIG. 8 shows a simplified electric system of a microwave oven according to this embodiment. In FIG. 8, a control circuit 20 as heating control means and microwave control means
Is composed of a circuit mainly composed of a microcomputer, and its input port is provided with the position detecting device 14,
The infrared sensor 15 and the key input unit 21 are connected. Although not shown, the key input unit 21 includes a menu setting key for setting a cooking menu, a heating time setting key for manually setting a heating time, a start key,
It is configured to include a reset key and the like.

The output port of the control circuit 20 is connected to the motor 9, the magnetron 6, and a display 22 as display means. The display 22 is composed of a color full dot LCD, and is disposed, for example, at the upper right of the front surface of the cabinet 1. The display 22 is for displaying the temperature distribution on the bottom plate 3, and as shown in FIG. 9, a rectangular screen corresponding to the bottom plate 3 displays the measurement field of each of the infrared detection elements p1 to p16. Are divided into 16 blocks B1 to B16 corresponding to.

At this time, the blocks B1 to B16 are:
The color is changed according to the detected temperature in each measurement visual field. In the present embodiment, the color is changed from red to yellow to blue in the order of the rainbow color arrangement as the detection temperature in each measurement visual field changes from high to low.

Further, the display 22 is configured to display the position of the opening 11d of the branch portion 11 of the rotating waveguide 8. Specifically, the display 22 is configured such that the frame portion of the block where the opening 11d is located is displayed thicker than the other blocks. For example, when the branching unit 11 is located at the home position P0, as shown in FIG.
The frame portions of B3, B6 and B7 are displayed thick. Thereby, the blocks B2, B3, B6, B
It can be seen that the food placed on the portion corresponding to No. 7 is strongly irradiated with direct microwaves.

The control circuit 20 has a magnetron drive circuit and a motor drive circuit, and a control program for heating operation is stored in the memory of the microcomputer. The control circuit 20 is configured to control the driving of the motor 9 so as to rotate the rotating waveguide 8 according to the control program and stop the rotating waveguide 8 at an appropriate rotation angle position.

In particular, in this embodiment, the electric field distribution in the heating chamber 2 corresponding to the rotation angle position of the rotary waveguide 8 is experimentally obtained in advance, and based on the detection result of the infrared sensor 15, The rotation waveguide 8 is configured to stop at an appropriate rotation angle position.

Next, the operation of the above configuration will be described. The user places the container containing the food on the bottom plate 3, operates the menu setting key of the key input unit 21, sets the cooking menu, and sets the heating time by operating the heating time setting key. And operate the start key.

Then, the control circuit 20 drives the motor 9 to rotate the rotary waveguide 8 and drives the magnetron 6 to start heating and cooking. As a result, the microwave generated by the magnetron 6 is guided to the rotating waveguide 8 through the main waveguide 7 and the excitation port 4, and the branch portions 11 to 1
Irradiation is performed into the heating chamber 2 from the opening portions 11c to 13c and the opening portions 11d to 13d.

At this time, the positions of the openings 11c to 13c and the openings 11d to 13d change according to the rotation of the rotary waveguide 8, so that the microwaves are dispersed and supplied into the heating chamber 2. In addition, the microwave guided to the rotating waveguide 8 is dispersed by the three branch portions 11 to 13 and
Therefore, the electric field distributions due to the microwaves supplied from the branch portions 11 to 13 overlap each other, and the electric field distribution in the heating chamber 2 becomes substantially uniform.

In parallel with this, the control circuit 20 periodically reads the temperature detection signals of the respective elements p1 to p16 of the infrared sensor 15 and obtains the temperature calculation value for each measurement visual field. Further, the control circuit 20 receives the calculated temperature value for each visual field and controls the display 2 so that each of the blocks B1 to B16 of the display 22 has a corresponding color. Further, the control circuit 20 controls the blocks B <b> 1 to B <b> 1 based on the position detection signal input from the position
The display 22 is controlled so that the thickness of the frame portion of the block corresponding to the opening 11d of the rotating waveguide 8 in B16 is displayed thick.

The control circuit 20 determines the temperature distribution of the food by judging the temperature calculation value of each visual field having a small temperature change as the background temperature and the one having a large temperature change as the food temperature. Then, when the food temperature varies, the rotating waveguide 8 is stopped at a rotation angle position where an electric field distribution in which the heating intensity is increased in a low temperature portion of the food is obtained.

According to the above configuration, the infrared sensor 15 is configured to have a plurality of measurement visual fields covering the entire area on the bottom plate 3, so that no matter where the food is placed on the bottom plate 3, The temperature of the food can be detected. Therefore, the entire bottom plate 3 can be effectively used, and the heating of the food can be controlled with high accuracy.

Particularly, in the present embodiment, the rotating waveguide 8 is provided, and the microwave is dispersed and supplied into the heating chamber 2 while the rotating waveguide 8 is rotating. The electric field distribution in the inside was configured to be substantially uniform. For this reason, the problem that the intensity of the electric field (that is, the heating energy) varies depending on the location in the heating chamber 2 is eliminated, and the food can be uniformly heated regardless of the placement location on the bottom plate 3.

Moreover, since the rotary waveguide 8 is branched in three directions from the center of rotation, the main waveguide 7 for guiding the microwave to the excitation port 4 and the branch portion 11 of the rotary waveguide 8 are formed.
The radio wave coupling with one or two of .about.13 is always in a good state. For this reason, the microwave can be satisfactorily supplied into the heating chamber 2, and the reflected wave to the magnetron 6 is reduced, so that the magnetron 6 can stably oscillate the microwave, thereby improving the oscillation efficiency and improving the life. Improvement can be achieved.

Further, since the rotation and stop of the rotary waveguide 8 are controlled based on the temperature distribution of the food detected by the infrared sensor 15, if the temperature varies depending on the portion of the food, the temperature is controlled. The rotating waveguide 8 can be stopped at a rotation angle position where the heating intensity is increased in a portion where the temperature is low, and the food can be efficiently heated.

Further, the infrared sensor 15 is connected to the sixteen infrared detecting elements p1 to p16 in one sensor case 17.
Since it is configured to be accommodated in the device, it is possible to reduce the size while having many measurement fields of view. In addition, heating room 2
The number of the infrared-transmitting windows 15a provided in the ceiling 2b can be reduced to one, so that the electric wave leakage from the heating chamber 2 can be reduced.

Also, since marks m1 to m16 representing the measurement field of view of the infrared sensor 15 are drawn on the surface of the bottom plate 3, the user recognizes that the entire area on the bottom plate 3 is a portion on which food can be placed. can do.

Further, in this embodiment, the display 22 for displaying the detection result of the infrared sensor 15, that is, the temperature distribution in the heating chamber 2, is provided. The state can be grasped. Therefore, the cooking time, the heating time, and the like can be appropriately adjusted according to the heating state of the food. In particular, in the present embodiment, the display 22 is constituted by a color full dot LCD, and the display is performed with different colors for each temperature, so that the temperature distribution can be easily grasped.

The display 22 also displays the control status of the rotary waveguide 8 together with the detection result of the infrared sensor 15, so that the user can know how the food is heated, that is, at the time of heating. It is possible to know whether the rotating waveguide 8 is rotating or stopped.

FIGS. 11 to 13 show a second embodiment (corresponding to claims 4 and 5) of the present invention, and the points different from the first embodiment will be described. In the second embodiment, a tray 3 which can be taken in and out of a bottom plate 3 of the heating chamber 2 is provided.
1 is provided. Therefore, in the present embodiment, the tray 3
1 functions as a food placing part. The tray 31 is configured to have a shape and a size that can just fit in the heating chamber 2.
It is made of heat-resistant glass or ceramic through which microwaves can pass.

In the cabinet 1, above the heating chamber 2, sixteen monocular infrared sensors 32 are provided in place of the infrared sensors 15. 16 corresponding to the infrared sensor 32 is provided on the ceiling 2 b of the heating chamber 2.
A plurality of windows 32a for transmitting infrared light are formed. In this case, as shown in FIG.
The heating chamber 2 is arranged in four rows and four columns in accordance with the dimension ratio of the horizontal cross-sectional shape of the heating chamber 2 in the vertical and horizontal directions.

Further, the infrared sensors 32 are arranged so that the individual measurement fields of the infrared sensors 32 formed on the bottom 31a of the tray 31 are substantially the same size. Further, the entire bottom portion 31a of the tray 31 is covered with the 16 measurement fields of view. At this time, as shown in FIG. 13, marks m <b> 1 to m <b> 16 representing the measurement visual field formed by each of the infrared sensors 32 are drawn on the bottom 31 a of the tray 31.

According to the above configuration, since the tray 31 that can be taken in and out of the heating chamber 2 is provided, it is easy to store food in the heating chamber 2 and take out food from the heating chamber 2. Further, when the tray 31 becomes dirty, the tray 31 can be taken out and washed, so that the portion on which the food is placed can be kept clean.

Further, since all the measurement fields formed on the bottom 31a of the tray 31 have substantially the same size, the detection accuracy for each measurement field can be the same. Since the configuration other than the above is the same as that of the first embodiment, the same operation and effect as those of the first embodiment can be obtained in this embodiment.

The present invention is not limited to the above-described embodiment, and for example, the following modifications are possible.
In each of the above embodiments, only the position of the opening 11d of the branch 11 in the rotary waveguide 8 is displayed on the display 22. However, the openings 11d to 1d of all the branches 11 to 13 are displayed.
You may comprise so that the position of 3d may be displayed.

The rotating waveguide is not limited to the above-described shape, and the position, size, number and the like of the openings may be changed. Moreover, you may comprise including four or more branch parts. The excitation port may be provided at the ceiling of the heating chamber, and the rotating waveguide may be provided at the top of the heating chamber.

When a plurality of infrared detecting elements are accommodated in one sensor case to constitute an infrared sensor, by setting each infrared detecting element to an appropriate size, the measurement visual field formed by each infrared detecting element can be increased. It is also possible to constitute so that it may become substantially the same size.

In each of the above embodiments, the rotary waveguide 8 is provided at the lower portion of the heating chamber 2 in accordance with the provision of the excitation port 4 at the bottom 2 a of the heating chamber 2. Therefore, the food and the rotating waveguide 8
The distances between the opening portions 11c to 13c and the opening portions 11d to 13d become shorter, so that more direct waves of microwaves hit the food. That is, the direct wave of the microwave greatly contributes to the heating of the food. For this reason,
By controlling the positions of the openings 11c to 13c and the openings 11d to 13d to adjust the distance from the food, the heating of the food can be controlled.

Therefore, based on the detection result of the infrared sensor 15, the open parts 11c to 11c
The rotation and stop of the rotating waveguide 8 may be controlled so that 3c and the openings 11d to 13d are close to each other. Also,
For example, bottom plate 3 like "warm milk" or "sakekan"
In the case of a cooking menu in which food containers are scattered and heated, a position on the bottom plate 3 where the food containers are placed is determined based on the detection result of the infrared sensor 15, and the food containers are placed. Opening parts 11c to 13c and opening part 11
The heating and cooking may be performed by stopping the rotating waveguide 8 so that d to 13d are close to each other. Even in such a configuration, the food can be heated evenly and efficiently.

[0062]

As is apparent from the above description, according to the microwave oven of the present invention, a food placing portion having substantially the same size as the horizontal section of the heating chamber is provided below the heating chamber, A main waveguide for guiding microwaves generated by the wave generator to an excitation port, and a microwave dispersing unit for dispersing the microwaves guided to the excitation port and supplying the dispersed microwave to a heating chamber; An infrared sensor having a plurality of measurement fields of view extending substantially over the entire upper surface portion and detecting the temperature of the food is provided, and the heating of the food by the magnetron is controlled based on the detection result of the infrared sensor. Even if food is placed on any part of the mounting part, the temperature of the food can be reliably detected, so that the entire food mounting part can be used effectively and heating can be controlled accurately. It is possible.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention and is a longitudinal sectional front view of a microwave oven.

FIG. 2 is a cross-sectional plan view of a heating chamber portion.

FIG. 3 is a plan view of a rotating waveguide.

FIG. 4 is a longitudinal sectional view taken along line AA of FIG. 3;

FIG. 5 is a plan view of an infrared sensor.

FIG. 6 is a side view of the infrared sensor.

FIG. 7 is a plan view of a bottom plate showing a display state of a mark indicating a measurement visual field of the infrared sensor.

FIG. 8 is a diagram showing an electrical configuration.

FIG. 9 is a front view of the display.

FIG. 10 is a perspective view of a position detection device.

FIG. 11 is a view corresponding to FIG. 1, showing a second embodiment of the present invention;

FIG. 12 is a plan view of a ceiling portion of a heating chamber.

FIG. 13 is a diagram corresponding to FIG. 7;

[Explanation of symbols]

In the drawing, reference numeral 2 denotes a heating chamber, 3 denotes a bottom plate (food placement portion), 4 denotes an excitation port, 6 denotes a magnetron (microwave generator), 7 denotes a main waveguide, and 8 denotes a rotating waveguide (microwave dispersion means). ), 9 are motors (driving means, microwave dispersion means), 15, 32
Denotes an infrared sensor, 17 denotes a sensor case, 20 denotes a control circuit (heating control means, microwave control means), 22 denotes a display means, 31 denotes a tray (food placement section), and p1 to p16 denote infrared detection elements.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 6/64 H05B 6/64 K 6/68 320 6/68 320Q 6/72 6/72 A F term ( Reference) 3K086 AA01 BA08 BB08 CA04 CA15 CB04 CC01 CD09 3K090 AA01 AB02 BA01 CA01 DA04 EA02 3L086 BB07 BB08 BB13 CB09 CB16 CB17 CC12 CC16 DA12 DA20 DA29

Claims (12)

[Claims] 1. A heating chamber for accommodating food, a microwave generator for generating microwaves, an excitation port provided in a chamber wall of the heating chamber, and a microwave generated by the microwave generator. A main waveguide for guiding the microwave to the excitation port, microwave dispersion means for dispersing the microwave guided to the excitation port and supplying the microwave to the heating chamber, and a horizontal section of the heating chamber provided at a lower portion of the heating chamber. A food placing part having substantially the same size as the above, an infrared sensor for detecting the temperature of the food, and heating control means for controlling heating of the food by the magnetron based on a detection result of the infrared sensor, A microwave oven, wherein the infrared sensor is configured to have a plurality of measurement fields of view that extend over substantially the entire food placement unit. 2. The microwave oven according to claim 1, wherein the infrared sensor comprises a plurality of infrared detecting elements housed in one case. 3. The infrared sensor has m × n measurement fields of view arranged so that the number of measurement fields is m in the vertical direction and n in the horizontal direction of the food placing unit (where m and n are integers). 2. The apparatus according to claim 1, wherein the ratio between m and n is substantially the same as the vertical and horizontal dimensional ratio of the food placing portion.
Or the microwave oven according to 2. 4. The microwave oven according to claim 1, wherein the infrared sensor is configured such that a plurality of measurement visual fields in the food placing unit have substantially the same size. . 5. The microwave oven according to claim 1, wherein the food placing section is constituted by a tray that is housed so as to be able to be taken in and out of the heating chamber. 6. The microwave oven according to claim 1, wherein a mark indicating a measurement visual field of the infrared sensor is attached to the food placing portion. 7. The microwave oven according to claim 1, further comprising control means for controlling the microwave dispersion means based on the detection result of the infrared sensor. 8. A microwave dispersion means for guiding microwaves into the heating chamber in communication with the excitation port, and a rotating waveguide having an opening for supplying microwaves to the heating chamber, 8. The electronic device according to claim 7, further comprising: a driving unit configured to rotationally drive the rotating waveguide, wherein the control unit is configured to control rotation / stop of the rotating waveguide. range. 9. The microwave oven according to claim 8, wherein the excitation port is provided at a bottom of the heating chamber. 10. The microwave oven according to claim 1, further comprising display means for displaying a detection result of the infrared sensor in each measurement field of view. 11. The microwave oven according to claim 7, further comprising display means for displaying a control state of the microwave dispersion means. 12. The display means is a color full dot LCD.
The microwave oven according to claim 10 or 11, wherein: