JP2009170335A - High frequency heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a high frequency heater equipped with an antenna capable of suppressing unevenness in heating. <P>SOLUTION: With conductive passages while two-branches of an antenna flat plate that radiates a high frequency and an antenna shaft that becomes a high frequency feeding part from a waveguide tube are used, a strong electric field is radiated in a wide region on the antenna flat plate, and the wide region in a heating chamber is heated relatively without unevenness. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a high-frequency heating device such as a microwave oven.

  A high-frequency heating device such as a microwave oven includes a heating chamber, a door that covers the front opening of the heating chamber so that it can be opened and closed, and a high-frequency oscillator that oscillates microwaves. ) Is fed into the heating chamber through a waveguide. Conventionally, in such a high-frequency heating device, as means for diffusing microwaves in the heating chamber and performing heating more efficiently, for example, “the inner surface of the base conductor is rotatably arranged oppositely with the center of gravity as a fulcrum, and A disk-shaped slot plate having a plurality of line slots for diffusing the microwave propagated from the microwave transmission path into the heating chamber; and a driving means installed outside the base conductor and applying a rotational driving force to the slot plate A ring-shaped choke disposed on the inner wall surface of the base conductor facing the peripheral edge portion of the slot plate; and an inner wall surface of the base conductor facing the peripheral edge portion of the slot plate; By providing a plurality of guide rollers that support the rotation of the slot plate, the position of the line slot that is the microwave discharge port of the slot plate and the object to be heated is changed. Is allowed to impart uniform microwave power distribution ", it was also a thing called (for example, see Patent Document 1).

JP 2004-327273 A (page 4-7, FIGS. 2 and 4) JP 2001-250672 A (page 3-7, FIG. 4)

  FIG. 1 is a cross-sectional view of a main part of a general high-frequency heating device used for home use. As shown in FIG. 1, a main body 1 of a high-frequency heating device includes a heating chamber 2 provided in a substantially rectangular parallelepiped, a high-frequency oscillator 3 that oscillates a high frequency, a waveguide 4 that propagates a high frequency, and a high frequency in the waveguide 4. An antenna 5 that diffuses into the heating chamber 1 is provided, and a high-frequency transmission plate 8 that serves as a protection plate for the antenna 5 and an installation plate for the article 9 to be heated is installed on the upper surface of the antenna 5.

There is a conventional example shown in FIG. 11 or FIG. 12 for the antenna 5 which is a means for diffusing the high frequency into the heating chamber 2 and the object 9 to be heated.
FIG. 11 shows a slot antenna provided on a flat plate (Patent Document 1), and FIG. 12 shows a dipole antenna provided on a part of the flat plate (Patent Document 2). The object to be heated 9 is heated by supplying high-frequency power from the section 16 and generating a strong high frequency locally in a slot or dipole installed on the antenna surface.

When such a conventional antenna shape is used, a high frequency is fed from the shaft connecting portion 16 connected to the waveguide 4, and this high frequency becomes a high frequency current on the disk, and the shaft is used as a feeding portion for incidence and reflection. Since only repetition is performed, a distribution of a portion that generates a high electric field locally and a portion that does not locally occur can be formed on the antenna.
Specifically, high frequency waves are strongly propagated to the slot portion 20 in the antenna provided with the slot (FIG. 11), and to the dipole tip portion 21 in the antenna provided with the dipole (FIG. 12). Therefore, the heated object 9 at this position is strongly heated.
If this event is paradoxically and relatively expressed, it means that there is a portion on the antenna that is not heated strongly. That is, there are a strong portion and a weak portion where the object 9 to be heated is irradiated with high frequency, and there is a problem that there is a portion that is well heated and a portion that is not heated so much, that is, uneven heating.
In addition, in order to alleviate the heating unevenness as described above, some antennas 5 are heated by heating, but eventually the strong electric field part moves concentrically, and the intensity of heating occurs concentrically. The challenge remains.

Furthermore, when trying to radiate radio waves efficiently, the optimum length of the slot antenna or dipole antenna is determined by the wavelength of the oscillating high frequency. For example, in the case of a slot antenna, radio waves are radiated most efficiently when the longitudinal dimension of the slot is ½ wavelength. In the case of the dipole antenna of the conventional example shown in FIG. 12, when the length from the shaft connecting portion which is a power feeding portion to the dipole tip portion 21 is ½ wavelength, the radio wave is most efficiently radiated. (Page 5 of Patent Document 1).
For example, in the case of 2.45 Ghz, which is a high-frequency wavelength used in a home microwave oven, the wavelength is 122.4 mm and the half wavelength is 61.2 mm. The size of the bottom surface of a microwave oven for home use is about 400 mm × 300 mm, even if it is large, and considering the arrangement of peripheral parts, the diameter of the flat plate of the antenna 5 needs to be about 200 mm at most.
Here, for example, when an attempt is made to install a large number of radial slot antennas as shown in the conventional example of FIG. 11 in a home microwave oven, an antenna having a slot size of approximately ½ wavelength that efficiently generates a high frequency is As a result, it is impossible to increase the efficiency of heating the object to be heated.

  That is, in order to promote efficient heating of the object to be heated 9 and to correct the unevenness in heating of the object to be heated 9, it is important to generate a uniform high frequency from a wide part on the antenna. Since the high frequency heating apparatus has an antenna shape that can only generate a strong electric field only locally, there is a problem that heating efficiency and heating unevenness correction are not sufficiently performed.

  The present invention has been made to solve the above-described problems, and provides a high-frequency heating apparatus that can be efficiently heated and that can suppress heating unevenness.

The high-frequency heating device according to the present invention is
A heating chamber for storing an object to be heated, a high-frequency oscillator for oscillating a high frequency for heating the object to be heated in the heating chamber, a waveguide for guiding the high frequency oscillated from the high-frequency oscillator to the heating chamber, An antenna for diffusing high-frequency waves propagated from the waveguide into the heating chamber,
The antenna includes a flat plate that emits the high frequency, and an antenna shaft that has one end disposed in the waveguide and has the other end connected to the flat plate and propagates the high frequency of the waveguide to the flat plate. The antenna shaft is connected to the antenna shaft by a conductive path branched from the upper part of the antenna shaft.

  The high-frequency heating device of the present invention connects a flat plate of an antenna that emits high-frequency waves and a shaft of an antenna that serves as a high-frequency power feeding portion from a waveguide through a bifurcated conductive path, thereby providing a wide area on the flat plate of the antenna. A strong electric field can be emitted. For this reason, it is possible to efficiently and uniformly heat a wide area in the heating chamber.

Embodiment 1 FIG.
An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of the main part of the high-frequency heating device according to Embodiment 1 of the present invention, and FIG. 2 is an external perspective view of the high-frequency heating device. The configuration shown in FIGS. 1 and 2 is basically the same as that of the above-described prior art.
FIG. 3 is a perspective view of the main part of the bottom surface of the heating chamber of the high-frequency heating device according to Embodiment 1 of the present invention, and shows the main part of the power feeding unit for propagating the high frequency into the heating chamber. 4 is a top view of the antenna 5 shown in the center of FIG.

First, the basic configuration of the high-frequency heating device according to the first embodiment will be described.
FIG. 2 is a side sectional view of a flat cabin type microwave oven, and an operation for inputting various types of information to the front (front) upper side portion of the housing composed of the main body 1 and a door 11 for opening and closing the front opening. A panel 10 is provided. When the user performs heating, the door 11 is opened, the article 9 to be heated is placed in the heating chamber 2, the door 11 is closed, and then the heating time and the heating temperature are set using the operation panel 10. And start cooking. The door 11 is provided with a door viewing window 12 made of a punching metal and glass sandwiching the punching metal, so that the cooking state of the article 9 to be heated in the heating chamber 2 can be confirmed. ing.

Next, a configuration for heating and a mechanism thereof will be described with reference to FIG.
In FIG. 1, a high-frequency oscillator 3 (magnetron) that oscillates a 2.45 GHz microwave is installed at the bottom of the heating chamber 2 of the main body 1. The microwave oscillated by the high frequency oscillator 3 propagates through the waveguide 4 and is transmitted to the antenna 5 through a round hole (feeding portion 13) provided in the bottom surface of the heating chamber 2, and further through the high frequency transmission plate 8, Irradiate the object 9 to be heated. The waveguide 4 is closed and configured with a conductor, and one end is connected to the high-frequency oscillator 3 and the other end is connected to the antenna shaft 52 of the antenna 5.
The antenna 5 includes an antenna flat plate 51, an antenna shaft 52, and a conductive path (not shown in FIG. 1, see FIG. 4), which is stored in the antenna storage portion 15. The antenna shaft 52 is connected to the antenna motor 6 provided at the lower part of the antenna 5. The antenna motor 6 is driving means for rotating the antenna 5. The invention according to the first embodiment is characterized by the antenna 5, and details of the configuration will be described later.
A high frequency transmission plate 8 is provided at a position that separates the antenna housing 15 and the heating chamber 2. The high-frequency transmission plate 8 is made of a non-dielectric material such as ceramic and transmits high frequency, and serves as a table on which the object to be heated 9 is placed.
Further, a temperature detection means 7 such as an infrared sensor is provided above the heating chamber 2 as a means for detecting the temperature in the heating chamber 2.

Here, a description will be given of how the microwave oscillated from the high-frequency oscillator 3 is irradiated to the object 9 to be heated in the above configuration.
For example, in the case of a microwave oven, a microwave of 2.45 GHz is oscillated from the high frequency oscillator 3. Thereby, in a microwave oven for home use, an output of about 1000 W can be obtained.
The oscillated microwave propagates through the space in the waveguide 4. The waveguide 4 and the heating chamber 2 are coupled by a round hole (feeding unit 13) provided in the bottom surface of the heating chamber 2, and the microwave propagating through the space in the waveguide 4 is round. It propagates into the heating chamber 2 via the hole (power feeding unit 13).

However, the microwave in the waveguide 14 does not flow efficiently into the heating chamber 2 simply by providing a round hole (feeding portion 13) on the bottom surface of the heating chamber 2. Therefore, the antenna 5 composed of the conductive antenna flat plate 51 and the antenna shaft 52 is provided, and the microwave is diffused into the heating chamber 2. The antenna flat plate 51 and the antenna shaft 52 of the antenna 5 are connected to each other by coaxial coupling, and the antenna flat plate 51 is disposed on the heating chamber 2 side.
In the antenna 5 configured as described above, the microwave propagating in the waveguide 4 is converted into a surface current by the antenna shaft 52 of the antenna 5. The converted current flows on the surface of the antenna 5, and a magnetic field is excited by the current along with the time change of the current by the microwave, and an electric field is generated by the excited magnetic field. Electromagnetic waves are radiated when the time change of the magnetic field and electric field increases or decreases with the phase of the high frequency.
That is, since a current flows on the surface of the antenna 5, the behavior of a high frequency wave propagating from the antenna flat plate 51 portion into the heating chamber 2 changes depending on how the surface current flows in the time change (phase change) of the microwave. . Therefore, a high frequency can be generated from a wide area on the antenna flat plate 51 by causing the current flowing on the surface of the antenna 5 and the time variation of the current to occur in a wider area. This phenomenon is a fundamental part of the present invention.

Next, the configuration of the antenna 5 according to Embodiment 1 of the present invention will be described in detail with reference to FIG.
FIG. 4 is a view of the antenna 5 as viewed from the vertical direction. The antenna flat plate 51 and the antenna shaft 52 are connected by a conductive path 14 a and a conductive path 14 b that are branched from the antenna shaft connection portion 16. The current supplied from the antenna shaft 52 merges on the antenna flat plate 51 as individual currents via the conductive path 14a and the conductive path 14b. The arrow line in FIG. 4 shows this current flow.

When the antenna 5 is viewed from above, the conductive path 14a enters the antenna flat plate 51 from the lower side of FIG. 4 and the conductive path 14b enters the antenna flat plate 51 from the right side of FIG.
The conductive path 14a and the conductive path 14b have different path lengths. Specifically, the length of the conductive path 14a is L, and the length of the other conductive path 14b is L + microwave wavelength. It is comprised so that it may become 1/4. Further, in order to secure the path, as shown in FIG. 4, a bend is formed so as to bypass the circular antenna flat plate 51.
In addition, the corner | angular radius 17 is formed in the bending part of the conductive path 14a and the conductive path 14b. As a result, it is possible to reduce the possibility of sparks due to concentration of the electric field at high output.

The antenna flat plate 51 has a circular shape whose diameter is approximately half the wavelength of the microwave, and is smaller than the antenna shown in the conventional example.
Also, as shown in FIG. 4, the center of gravity of the antenna 5 is not on the antenna shaft 52 and is in an eccentric state. Therefore, in order to ensure rigidity especially when the inside of the heating chamber 2 is at a high temperature, the plate thickness of the antenna 5 is 0. .3 mm or more, preferably 0.5 to 2 mm.

By providing the two-branch conductive path as described above, the inflow via the conductive path 14a, that is, the high-frequency current flowing from below when the antenna 5 is viewed from above, and the inflow via the conductive path 14b, That is, the high-frequency current flowing from the right side when the antenna 5 is viewed from the upper surface is combined in a vector manner on the antenna flat plate 51. Therefore, various currents flow on the antenna flat plate 51, and the generated electromagnetic waves are also diversified.
Further, when the conductive path 14a and the conductive path 14b are viewed as current sources in the antenna flat plate 51, these conductive paths are incident on the antenna flat plate 51 at a substantially right angle. It will be shifted by 90 °. In addition, since a difference corresponding to a quarter wavelength of the microwave is provided in the path lengths of the two conductive paths, the phase of the current incident on the antenna flat plate 51 is also shifted by 90 ° between the two conductive paths. By utilizing the displacement and the phase shift, circular polarization that can radiate a high electric field in an annular shape can be generated on the antenna flat plate 51.

Next, the principle of circularly polarized wave generation will be described with reference to FIG.
FIG. 5 schematically shows the current flowing on the antenna flat plate 51. The current flowing on the antenna flat plate 51 is indicated by a solid line and the current incident from the conductive paths 14a and 14b is indicated by a broken line. . The length of the broken line indicates the magnitude of the current, and the longer the length, the larger the current.
The current excited by the microwave changes so that the flowing direction is reversed every 90 ° phase. For example, incident light from the conductive path 14a flows greatly downward at a phase of 0 °, but the current decreases as the phase changes to 22.5 ° and 45 °, and then the direction of current flow is reversed. At the beginning (phase 67.5 °), the phase 90 ° has the same magnitude as the phase 0 ° and flows in the reverse direction.
This is the same phenomenon when incident from the conductive path 14b flowing in from the right side when the antenna 5 is viewed from above, but the inflow distance from the antenna shaft 52, which is a current source, to the antenna flat plate 51 is the conductive path 14a. Because of the difference, the magnitude of the current flowing into the antenna flat plate 51 at the same time differs between the conductive path 14a and the conductive path 14b.

The current incident from the conductive path 14a and the conductive path 14b is a combined current indicated by a solid line on the antenna flat plate 51 in FIG. As a result, the direction of the current flowing on the antenna flat plate 51 is rotated once while the phase changes by 180 °.
That is, the electromagnetic wave generated in the vertical direction of the antenna flat plate surface along with the movement of the current moves along the strong electric field portion with an annular phase.

Since this phenomenon is an event performed at a frequency of 2.45 GHz in a home microwave oven, the time for a strong electric field portion to make one rotation on a flat plate is 1/450 million parts per second.
This time order is much smaller than the heating time (usually several tens of seconds to several tens of minutes) for heating the article 9 to be heated and the rotation speed of the antenna 5 (usually about 5 to 6 rpm). Therefore, the to-be-heated object 9 is substantially equivalent to being given a strong electric field in an annular shape by the antenna flat plate 51.
FIGS. 6A and 6B are schematic diagrams of an electric field generated by the antenna 5. FIG. 6A shows an antenna according to the present invention, and FIG. 6B shows a conventional dipole antenna. As shown in the figure, in the conventional antenna (B), a strong electric field is generated only in the tip portion of the dipole and the upper, lower and left space portions. On the other hand, in the antenna (A) according to the present invention, a strong electric field is generated in an annular shape.

Further, during cooking (during microwave oscillation), the antenna 5 can be rotated by driving the antenna motor 6 shown in FIG.
FIGS. 6C and 6D are schematic diagrams of electric field intensity distribution when the antenna is rotated. FIG. 6C shows an antenna according to the present invention, and FIG. 6D shows a conventional dipole antenna. The shaded portion is an electric field strength distribution synthesized on the assumption that the antenna has rotated 360 degrees once. A darker shaded area indicates a stronger electric field.
As described above, in the antenna of the present invention, a strong circular electric field is emitted on the flat plate. Therefore, when the antenna is rotated, heating can be performed in a wide area. In contrast, the conventional product is an antenna that emits a strong electric field locally, so that a strong electric field and a weak electric field are generated concentrically, and the weak electric field is wider. Comparing the areas of the strong electric field portions (shaded portions) of (C) and (D), it is clear that the antenna according to the present invention generates a strong electric field in a wider range.
Furthermore, in the antenna 5 according to the present invention, since the current flows from the shaft as the current source in both the conductive paths 14a and B15, the electromagnetic wave is also emitted from here. Therefore, in the conventional product with the shaft in the center, the antenna central portion has a tendency to weakly heat (FIG. 6D), but this can be mitigated in the antenna 5 according to the present invention.

As described above, since the antenna flat plate 51 and the antenna shaft 52 are connected by the bifurcated conductive path, the strong electric field portion on the antenna flat plate 51 can be moved for each high-frequency phase. For this reason, strong field emission can be realized in a wide area of the antenna flat plate 51, and a wide area of the heating chamber 2 can be heated relatively uniformly.
Further, since the two branched conductive paths are configured to be incident at substantially right angles, the effect of moving the strong electric field portion is increased, and the current flowing on the antenna plate 51 can be further diversified.

  In addition, one of the two branched conductive paths is made longer by ¼ wavelength than the other, so that the phase of the high-frequency current flowing into the flat plate is shifted by ¼ wavelength. Can flow into the antenna flat plate 51. That is, the currents excited simultaneously in the shape of a shaft flow into the antenna flat plate 51 in a state where the respective phases are changed. Therefore, when the synthetic vector of the current flowing through the flat plate changes periodically, so-called circularly polarized waves can be generated in which a strong radio wave is spirally emitted from the antenna flat plate in the upward direction of the heating chamber. Thereby, it becomes possible to widen the absorption range of food, and as a result, it is possible to obtain an effect of giving an efficient and uniform temperature rise effect to the object to be heated.

  Further, by using the antenna rotation together, more uniform heating can be performed over a wider range.

Embodiment 2. FIG.
In the above-described first embodiment, an example in which one antenna 5 is provided is shown, but in the second embodiment, an example in which a plurality of antennas 5 are installed is shown. The high-frequency heating device according to the second embodiment is basically the same as that of the first embodiment except for the arrangement of the antenna 5, and therefore, only the parts different from the first embodiment will be described below.

FIG. 7 is a schematic diagram of the arrangement of the antenna 5 on the inner bottom surface of the high-frequency heating device according to the second embodiment. As shown in FIG. 7, the high frequency heating apparatus according to the second embodiment is provided with four antennas 5. Conventional antennas (FIGS. 11 and 12) take advantage of the characteristic of efficiently generating radio waves when the slot antenna or dipole antenna is ½ wavelength long as described above. Therefore, as described above, the antenna must be enlarged to some extent. For this reason, when considering the bottom size (about 400 mm × 300 mm) of a general household microwave oven, even if four antennas are to be installed, the antennas interfere with each other and cannot be installed.
On the other hand, the antenna 5 according to the present invention includes the antenna flat plate 4, the conductive path 14a, and the conductive path 14b, and is smaller in size than the conventional one, so that four antennas can be installed.
By installing four antennas as described above, it is possible to emit a broader and more uniform strong electric field than in the case of one antenna.

Also, the four installed antennas can be rotated. FIG. 8 schematically shows how one of the four antennas rotates and its strong electric field. Assuming that the four antennas are A, B, C, and D for convenience, after A is rotated for a certain period of time, it is stopped at a position that does not interfere with the rotation of other antennas. Subsequently, after rotating B for a predetermined time, it is stopped at a position where it does not interfere with the rotation of other antennas. The same operation is performed for C and D in order, and a series of rotation operations of A, B, C, and D are repeated during heating.
By the rotation operation described above, the electric field intensity distribution in the heating chamber can be made extremely leveled as a whole. Therefore, compared with Embodiment 1, it becomes possible to make the heating state in the whole area in the heating chamber 2 more uniform.

  In the second embodiment, an example in which four antennas are installed has been described. However, the number of antennas is not limited to this, and the number of antennas is not limited as long as the antennas are arranged so as not to interfere with each other. Does not matter.

Embodiment 3 FIG.
In the first embodiment described above, the example in which the antenna 5 is continuously rotated during the heating has been described. In the third embodiment, an example in which the rotation of the antenna 5 is controlled in accordance with the temperature state in the heating chamber 2 is described. To do.
In addition, since the structure of the high frequency heating apparatus which concerns on this Embodiment 3 is fundamentally the same as Embodiment 1, a different part from Embodiment 1 is demonstrated below.

A temperature detection device 7 shown in FIG. 1 is a non-contact infrared sensor for detecting the temperature in the heating chamber 2. In particular, when a compound eye infrared sensor, such as a 4 × 4 thermopile array sensor, is used, more precise temperature detection is possible.
FIG. 9 is a schematic diagram of the bottom surface of the high-frequency heating device according to Embodiment 3 of the present invention.
In FIG. 9, the inside of the high-frequency transmission plate 8 is virtually divided into 16 parts, and these areas are referred to as detection areas 18. The temperature detection device 7 can detect the temperature for each divided region of the detection region 18.
Furthermore, the high-frequency heating device according to the present invention has a control means (not shown), and the control means controls the rotation of the antenna 5 by controlling the drive of the antenna motor 6 based on the temperature detected by the temperature detection device 7. And control the stop.

Next, the operation will be described. When heating is started, the temperature detection device 7 detects the temperature of each detection region 18 in the heating chamber 2. When detecting the low temperature region 19 that is determined to be relatively low temperature, the temperature detecting device 7 transmits the information of the low temperature region 19 to the control means, and the control means detects the antenna 5 immediately below the low temperature region 19. The antenna 5 is rotated so that the antenna flat plate 51 is arranged, and the flat plate 13 is moved and stopped.
By performing such a control operation, even if the heating state of the heated object is uneven and a low temperature region is generated, the low temperature region can be concentrated and heated. Since the heating effect of an arbitrary specific region can be enhanced, a high-frequency heating device capable of performing fine heating control that suppresses heating unevenness can be realized.

  In the third embodiment, an example in which there is one antenna is shown. However, as shown in the second embodiment, the present invention can also be applied to a case where a plurality of antennas are installed. By installing a plurality of antennas and controlling the rotation of the antennas according to the detected temperature, heating can be performed more quickly and uniformly.

  In the above description, an example in which the antenna flat plate 51 is circular has been described, but a rectangular flat plate shown in FIG. 10 may be used. In the rectangular shape, the length of one side is at least a half wavelength of a high frequency transmitted from a high frequency oscillator. Even in this case, current synthesis on the antenna surface is possible, and various electric fields can be generated in the same manner as a circular antenna plate.

  In the high-frequency heating device according to the present invention, a radiant heater, which is a heating device, can be provided on the top surface of the heating chamber, a hot air heater can be provided on the back surface, or combined with a steam generator.

It is principal part sectional drawing of the high frequency heating apparatus which concerns on Embodiment 1 of this invention. 1 is an external perspective view of a high-frequency heating device according to Embodiment 1 of the present invention. It is a principal part perspective view of the heating chamber bottom face of the high frequency heating apparatus which concerns on Embodiment 1 of this invention. It is a top view of the antenna of the high frequency heating device concerning Embodiment 1 of the present invention. It is a transition figure of the surface current on the antenna of the high frequency heating device concerning Embodiment 1 of the present invention. It is a strong electric field distribution map in the heating chamber bottom face of the high frequency heating device concerning Embodiment 1 of the present invention. It is a schematic diagram of antenna arrangement | positioning and strong electric field distribution of the high frequency heating apparatus which concerns on Embodiment 2 of this invention. It is a schematic diagram of antenna arrangement | positioning and strong electric field distribution at the time of rotating the antenna of the high frequency heating apparatus which concerns on Embodiment 2 of this invention. It is a top view which shows the detection area | region in the heating chamber bottom face of the high frequency heating apparatus which concerns on Embodiment 3 of this invention. It is a top view of the square antenna of the high frequency heating device concerning other embodiments of the present invention. It is an antenna top view of the conventional high frequency heating apparatus. It is an antenna top view of another conventional high-frequency heating device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Main body, 2 Heating chamber, 3 High frequency oscillator, 4 Waveguide, 5 Antenna, 51 Antenna flat plate, 52 Antenna shaft, 6 Antenna motor, 7 Temperature detection apparatus, 8 High frequency transmission plate, 9 Object to be heated, 10 Operation panel, DESCRIPTION OF SYMBOLS 11 Door, 12 Door visual recognition window, 13 Electric power feeding part, 14a, 14b Conductive path, 15 Antenna accommodating part, 16 Shaft connection part, 17 square radius, 18 Detection area | region, 19 Low temperature area | region.

Claims (13)

A heating chamber for storing an object to be heated;
A high-frequency oscillator that oscillates a high frequency for heating an object to be heated in the heating chamber;
A waveguide for guiding high-frequency waves oscillated from the high-frequency oscillator to the heating chamber;
An antenna for diffusing high-frequency waves propagated from the waveguide into the heating chamber;
The antenna includes a flat plate that emits the high frequency, and an antenna shaft that has one end disposed in the waveguide and connects the flat plate to the other end and propagates the high frequency of the waveguide to the flat plate,
The flat plate and the antenna shaft are connected by a conductive path branched in two from the upper part of the antenna shaft. The conductive path bifurcated from the antenna shaft tip is
The high frequency heating apparatus according to claim 1, wherein the other is longer by a quarter wavelength of the high frequency oscillated from the high frequency oscillator. The conductive path bifurcated from the antenna shaft tip is
The high-frequency heating device according to claim 1, wherein the high-frequency heating device is connected at a substantially right angle when viewed from the vertical direction of the flat plate surface. The flat plate
The high-frequency heating device according to any one of claims 1 to 3, wherein a length of at least one side is a square shape having a substantially half wavelength of a high frequency oscillated from the high-frequency oscillator. The flat plate
The high-frequency heating device according to any one of claims 1 to 3, wherein the diameter is a circular shape having a half wavelength of a high frequency oscillated from the high-frequency oscillator. The high-frequency heating device according to any one of claims 1 to 5, wherein a driving unit that drives the antenna is provided, and the antenna is rotated by the driving unit. Detection means for detecting the temperature of the object to be heated;
Control means for controlling rotation and stop of the antenna by controlling the drive means based on the temperature detected by the detection means;
The high-frequency heating device according to claim 6, comprising:   The high-frequency heating device according to claim 7, wherein the detecting means is a compound eye infrared sensor capable of detecting a plurality of regions.   The high frequency heating apparatus according to claim 1, wherein a plurality of the antennas are provided. Providing a plurality of the antennas;
The high-frequency heating device according to any one of claims 6 to 8, wherein the control means controls to rotate a part of the plurality of antennas and stop others. In the heating chamber, an antenna storage portion for storing the antenna, a high-frequency transmission plate for partitioning the antenna storage portion and the heating chamber and protecting the antenna,
The high-frequency heating device according to claim 1, comprising:   The high-frequency heating device according to any one of claims 1 to 11, wherein the bent portion of the conductive path is rounded.   The high-frequency heating device according to any one of claims 1 to 12, wherein a thickness of a flat plate portion of the antenna is 0.3 mm or more.

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