JP3103745B2 - High frequency heating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply structure (a method of applying an electromagnetic wave to a heating chamber) of a high-frequency heating device for heating an object to be heated such as food, and more particularly to a structure for uniforming a heating distribution. is there.

[0002]

2. Description of the Related Art A microwave oven, which is a typical high-frequency heating apparatus, has conventionally been configured as shown in FIGS.

The microwave oven shown in FIG.
This is a general configuration using. Here, the electromagnetic wave emitted from the magnetron 1 as an electromagnetic wave radiating part is transmitted through the waveguide 2, and in the heating chamber 4, a standing wave determined by the shape of the heating chamber 4 and the position of the opening 29 from which the electromagnetic wave is radiated. The food 5 generates heat according to the electric field component of the standing wave and the dielectric loss of the food 5. The power P [W / m3] absorbed per unit volume of food is determined by the applied electric field strength E [V /
m], frequency f [Hz], and relative permittivity ε of food 5
r and the dielectric loss tangent tan δ are expressed as equation (1). When the opening is formed on the side surface or the top surface, the heating distribution of the food 5 is substantially determined by the standing wave distribution of the electromagnetic wave. Therefore, in order to suppress the unevenness of the heating distribution, the turntable 10 is driven to rotate and the concentric heating is performed. The distribution is made uniform.

P = (5/9) · εr · tanδ · f · E2 × 10−10 [W / m3] (1) As another means for uniformity, electromagnetic waves are generated by constant rotation of a metal plate in a heating chamber. The stirrer method for stirring
As described above, there is a so-called rotating waveguide system in which electromagnetic waves are extracted from the waveguide 2 by a rotating body (rotating antenna 6) having the antenna 30, and the opening itself is rotated at a constant rate. In this case, the rotating antenna 6 is formed on the bottom surface of the heating chamber 4 and is constantly rotated by the motor 7 at all times. The heating chamber 4 is entirely covered with a cover 31 made of a material through which electromagnetic waves can pass. But in fact,
Turntable type products are the most commercially available.

[0005] In addition, there is a type in which a plurality of openings are provided to switch the outlet of the electromagnetic wave to achieve uniformity. FIG.
Is a type in which two openings 29 are provided on the wall surface of the heating chamber 4 (Japanese Patent Laid-Open No. 4-319287).

In order to form a plurality of openings, there is a type having a plurality of magnetrons and a plurality of waveguides (JP-A-61-181093, JP-A-4-345).
788).

In order to form a plurality of openings, a single magnetron is used. However, there is a type in which a plurality of waveguides are branched from one waveguide in multiple directions (Japanese Patent Laid-Open No. 61-2).
No. 40029, Japanese Utility Model Laid-Open No. 1-129793).

Further, as shown in FIG. 23, the end faces 32 of the two sub-waveguides 31 are moved at positions opposed to the plurality of openings 29, and the openings 29 where apparent electromagnetic waves are likely to be output are switched to aim at uniformity. Is also available (JP-A-5-74566).

Further, as shown in FIG.
In some cases, by moving the metal 33 within the single waveguide 2 having the above-mentioned characteristics, the openings 29 where the electromagnetic waves are likely to appear are switched to achieve uniformity (see JP-A-3-11588 and JP-A-5-121160). No.).

[0010] The weight, shape,
Devices that perform feedback control by detecting temperature, dielectric constant, temperature, humidity, electric field, and the like in a heating chamber have been put to practical use.

[0011]

However, in the above-mentioned conventional structure, when the waveguide and the heating chamber are connected and electromagnetic waves are introduced into the heating chamber, an appropriate opening for making the heating distribution uniform for each material and shape of the food. There is a problem that the positions of the portions are different, and it is not possible to uniformly heat all foods with one opening.

For example, it is generally known that when flat food is heated with a conventional microwave oven, heating proceeds from the edge and remarkable uneven heating occurs in which the center remains cold.

A feature of the position of the opening is that when the opening is provided in the vicinity of the center of the bottom of the heating chamber, the bottom of the food is heated, and if the food is liquid with convection, the food can be heated uniformly, but there is no convection. Solid foods have the problem that the temperature rises only at the bottom. At this time, if the turntable is used, the heating distribution on the concentric circle can be made uniform, but no matter how much the turntable is rotated, the distribution in the radial direction and the distribution in the vertical direction viewed from the center of rotation are not improved.

In the case of a stirrer or a rotating waveguide, which stirs an electromagnetic wave, the electric field distribution is changed in such a manner that the opening is changed in accordance with the rotation.
There is an effect of avoiding concentration a little in menus that want to avoid concentration of electromagnetic waves as much as possible, such as thawing cooking. However, since the stirring is performed at a constant rotation regardless of the food, heating is performed by repeating the same electric field distribution every rotation of any food, so that complete uniformity cannot be achieved. Further, when the electromagnetic wave is stirred, the reflected wave to the magnetron continuously increases and decreases, so that the magnetron is used in an unstable operation region, thereby increasing unnecessary radiation and increasing the temperature of the magnetron. In the past, to prevent these problems, new components had to be added for noise reduction of the magnetron, and the configuration had to be devised to increase the cooling capacity.

Even when a plurality of openings are provided, a fixed electric field is generated only by opening the openings at the same time, and it is difficult to equalize the heating distribution of all foods. There is no great difference between the heating distribution of the microwave oven and the microwave oven of FIG. After all, unless the proper opening is switched for each food item, the user cannot achieve a satisfactory finished state.

In the case of a device having a plurality of magnetrons and a plurality of waveguides, a waveguide for guiding an electromagnetic wave is switched by controlling the oscillation of each magnetron. For this reason, the opening from which the electromagnetic wave is emitted is also switched, which is effective for making the heating distribution uniform. However, if the number of magnetrons is increased, the price becomes high, the weight becomes heavy, and it is difficult to carry.

Further, there is a single magnetron that branches a plurality of waveguides from one waveguide in multiple directions. However, it is not possible to completely switch an opening through which an electromagnetic wave is easily emitted. There is a problem that a certain amount of electromagnetic waves is emitted from the opening where it is not desired to emit light. Further, there is a problem that a large amount of sheet metal material required for the waveguide is required, so that the cost is high and it is difficult to manufacture the waveguide.

Therefore, as shown in FIG. 23, there is a method in which the end face of the sub-waveguide is moved at a position facing a plurality of openings to switch the openings where apparent electromagnetic waves are likely to be emitted. It is valid. However, considering an actual configuration, a space occupied by a plurality of sub-waveguides and a space for a plurality of shield configurations for preventing leakage of electromagnetic waves when moving the end face of the sub-waveguide are required. Therefore, there is a problem that the size of the entire microwave oven becomes large or the effective volume of the inside of the heating chamber with respect to the whole size becomes small. For the user, if the overall size is large, it is difficult to place it, and if the effective volume is small, the user is dissatisfied that only small foods can be contained. Similarly, the microwave oven becomes heavy, causing a problem that it is difficult to carry. Operating the end face of the sub-waveguide including the shield configuration at a plurality of locations may consume considerable power.

Also, as shown in FIG. 24, even if a metal is moved in a single waveguide having a plurality of openings, it is impossible to completely switch the openings through which electromagnetic waves can easily be emitted, and it is desired to emit electromagnetic waves. There is a problem that a certain amount of electromagnetic waves is emitted from the opening that is not provided. Further, in the configuration shown in FIG. 24, it is not clear how to move the electromagnetic wave from which opening.

In addition, sensors that detect the state of food with sensors and perform feedback control include weight sensors, humidity sensors, temperature sensors, electromagnetic field detection sensors, steam detection sensors, and the like.
Some sensors, such as an alcohol detection sensor, detect a state at the beginning of heating, a change in state from the beginning of heating, or an end of heating. However, none of these sensors has been put to practical use for detecting the distribution of heating or performing feedback control so as to correct uneven heating.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to realize a high-frequency heating apparatus for making a heating distribution of an object to be heated uniform.

[0022]

Means for Solving the Problems A high-frequency heating apparatus according to the present invention has the following configuration to solve the above-mentioned problems.

[0023] The present invention includes a heating chamber for loading and unloading an object to be heated, it rotated by placing the object to be heated, electromagnetic waves
Metal or conductive material that has
A turntable that, a first driving unit for driving the turntable, and an electromagnetic wave radiating unit for radiating electromagnetic waves, the direction of the electromagnetic <br/> wave emitted from below the turntable to the object to be heated, From the center of the turntable to the outer edge
Can be changed to a predetermined position , and by proximity radiation
A feed port switching unit that can heat the targeted site, the waveguide guiding the electromagnetic wave radiated from said electromagnetic wave radiation part to the feed port switching unit, wherein the electrostatic driving said feed port switching unit
A second drive unit for changing the direction of the magnetic wave,
A position detector for detecting the radial wave, depending on the radiation direction of the electromagnetic wave detected by said position detecting unit, the radiation amount of electromagnetic waves from the electromagnetic wave radiation part, the first drive unit and <br/> the first A control unit for controlling each of the two drive units ,
By changing the relative position of the object to be heated and the direction of the electromagnetic wave,
Operate the heater to heat it evenly, or
Is operated so as to heat intensively . In addition, the turntable has a rotation direction of 1 /
It was configured to have a gap having a length of 2 or more .

A heating chamber for taking in and out the object to be heated;
A material on which the object to be heated is placed and rotated to transmit an electromagnetic wave.
A turntable consisting of
First drive unit that emits electromagnetic waves and an electromagnetic wave emission unit that emits electromagnetic waves
Irradiates the object to be heated from below the turntable.
From the center of the turntable to the outer edge
Can be changed to a predetermined position, and proximity radiation
Power supply port switching unit that can heat the target area by
The electromagnetic wave emitted from the electromagnetic wave emission part
The waveguide leading to the switching unit and the power supply port switching unit.
A second driving unit that changes the direction of the electromagnetic wave, and heating is started.
A position detection unit for detecting a radiation direction of the previous electromagnetic wave;
Depending on the radiation direction of the electromagnetic wave detected by the
The radiation amount of the electromagnetic wave from the electromagnetic wave radiation unit, the first drive
And a control unit for controlling the second drive unit, respectively.
To change the relative position of the direction of the electromagnetic wave and the object to be heated,
The heater may be operated so as to heat it uniformly,
It is configured to operate to heat the fixed part intensively .

Further, the power supply port switching unit is provided for controlling the direction of the electromagnetic wave.
Is changed continuously .

The waveguide is radiated from the electromagnetic wave radiating portion.
Electromagnetic waves are guided to the heating chamber through the power supply chamber, and the power supply port is switched
The electromagnetic wave entering the heating chamber is formed in the power supply chamber.
Is changed .

Further, the bottom surface of the heating chamber has a configuration in which a circle having a radius R satisfying R> r has a slope that is upwardly convex with respect to the rotation center of the turntable having a radius r.

The control unit controls the second drive unit so that the direction of the electromagnetic wave from the power supply port switching unit is directed to the center of the bottom surface of the heating chamber immediately after the start of heating, and thereafter to the outside of the bottom surface of the heating chamber. The configuration was adopted.

A detector for detecting at least one of a physical quantity of the object to be heated or a variation thereof or a physical quantity indicating a state in the heating chamber or a variation thereof, and a heating progress state or an end time based on an output of the detection section. The control unit controls the second driving unit to drive the power supply port switching unit before the object to be heated is excessively partially heated.

A detector for detecting at least one of a physical quantity of the object to be heated or a variation thereof or a physical quantity indicating a state in the heating chamber or a variation thereof, and a heating progress state or termination based on an output of the detection section. The control unit estimates at least one of the times, and when thawing the object to be heated in a frozen state, continuously emits electromagnetic waves in a range where the maximum temperature of the object to be heated is estimated to be 0 ° C. or less, and heats the object. Then, when the maximum temperature of the object to be heated is estimated to exceed 0 ° C., the electromagnetic wave radiating section is controlled so as to temporarily stop the emission of the electromagnetic wave.

Further, the control unit is configured to control the driving of the power supply port switching unit during a suspension time from when the emission of the electromagnetic wave is temporarily stopped until the next emission is started.

In addition, a configuration is adopted in which the pause time from the stop of the emission of the electromagnetic wave to the start of the next emission is determined by the output of the detection unit. In addition, the detection unit includes at least one of a temperature detection unit that detects the temperature of the object to be heated and a weight detection unit that detects the weight of the object to be heated.

The present invention has the following effects by the above configuration. In claim 1, first, radiate from the electromagnetic wave radiation part.
The transmitted electromagnetic wave is output through the waveguide and the feed port switching unit.
While being guided into the heating chamber from below the
Turntable is a metal with a gap through which electromagnetic waves can pass
Or, because it is made of a conductive material,
Electromagnetic waves will be emitted in close proximity, and the emitted electromagnetic
Most of the waves are absorbed in the area near the radiation direction in the object to be heated.
Will be collected. In other words, the direction of the electromagnetic wave
It has the first effect of matching. Next turntable
The object to be heated is placed and rotated by the first drive unit.
be able to. In addition, the power supply port switching unit is used for the second drive.
The direction of the electromagnetic wave from the center of the turntable to the outer edge
Can be changed to a predetermined position. So turn
The combination of the table and the power supply
It can direct the direction of electromagnetic waves to any part of the heating object
It has the second effect of cutting. In addition, the control unit
Based on the radiation direction of the electromagnetic wave before the start of heating detected by the detector
In addition, the amount of electromagnetic radiation from the electromagnetic radiation section, the first drive section
And the second drive unit, respectively, so that the
An arbitrary amount of radiation can be emitted to any part.
It has the third effect of turning off. Therefore, the above action
Operation to uniformly heat the object to be heated,
Can be operated to intensively heat the fixed part
You.

According to a second aspect of the present invention, the turntable is
Made of metal or conductive material.
Since there is a gap longer than half the wavelength,
The electromagnetic waves below the cable easily pass upward through the gap
be able to.

According to the third aspect, first, an electromagnetic wave radiating portion
The electromagnetic waves radiated from the
And when it is led into the heating chamber from under the turntable
The turntable is made of a material that transmits electromagnetic waves
Therefore, radiate electromagnetic waves from the bottom of the object
Most of the radiated electromagnetic waves are inside the object to be heated.
Is absorbed by the part near the radiation direction of That is, the electromagnetic wave
The first effect is that the direction matches the heated area as it is.
I do. Next, the turntable is added by the first drive unit.
A hot substance can be placed and rotated. Also cut off the power supply
The switching unit uses the second drive unit to target the direction of the electromagnetic wave.
Predetermined position of the outer edge from the center of the table
Can be changed up to. Switching between turntable and power supply
Parts can be applied to any part of the object to be heated.
It has the second effect of being able to direct the direction of the magnetic wave.
I do. In addition, the control unit starts heating detected by the position detection unit.
Based on the radiation direction of the previous electromagnetic wave,
The radiation amount of the magnetic wave, the first drive unit and the second drive unit
Control, so that any radiation amount can be
Has the third effect of being able to emit electromagnetic waves
I do. Therefore, the object to be heated is uniformly heated by the above operation.
Or to heat specific areas intensively.
Can be operated as follows.

The power supply port switching unit according to claim 4
Continuously changes the direction of electromagnetic waves,
No direction in which electromagnetic waves cannot be emitted in the radial direction of the
The direction can be switched at the finest intervals.
Further, the electromagnetic wave is supplied to the heating chamber via the power supply chamber.
To form a power supply port switching unit in the power supply room,
The power supply switching unit does not protrude into the heating chamber.

In the sixth aspect of the present invention, the bottom surface of the heating chamber has an upwardly convex slope in a circle having a radius R where R> r around the center of rotation of the turntable having a radius r. Is difficult to enter between the turntable and the convex slope.

According to a seventh aspect of the present invention, since the direction of the electromagnetic wave is directed to the center of the bottom surface of the heating chamber after the start of heating, the center of the object to be heated is mainly heated, and then the direction of the electromagnetic wave is started. Is directed to the outside of the bottom of the heating chamber, so that the periphery of the object to be heated is mainly heated.

In addition, since the power supply port switching unit is driven before the object to be heated is partially heated by the output of the detecting unit according to claim 8, the heating portion of the object to be heated can be changed. .

According to the ninth aspect of the present invention, when the object to be heated is thawed, electromagnetic waves are continuously radiated and heated in a range where the maximum temperature of the object is estimated to be 0 ° C. or less. Is temporarily stopped, so that the temperature rise in the portion that has already been thawed can be temporarily suppressed.

Further, since the power supply port switching unit is driven when the emission of the electromagnetic wave is stopped in claim 10, the electromagnetic wave in the heating chamber is not agitated by driving the power supply port switching unit.

According to the eleventh aspect, the temporary stop time of the radiation of the electromagnetic wave is determined by the output of the detecting unit. The rate of temperature rise due to the difference from the atmosphere temperature in the heating chamber can be determined. Claim 12
Since the detection unit is constituted by at least one of the temperature detection unit and the weight detection unit, the state of the object to be heated can be easily estimated with a simple configuration.

[0043]

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

FIG. 1 is a sectional view of a high-frequency heating device according to one embodiment of the present invention. An electromagnetic wave emitted from a magnetron 1 which is a typical electromagnetic wave radiating part is radiated into a heating chamber 4 via a waveguide 2 and a power supply chamber 3, and heats a food 5 which is an object to be heated in the heating chamber 4. . The electromagnetic wave in the waveguide 2 is extracted by the rotating antenna 6 which is a power supply port switching unit in the power supply chamber 3. Since the rotating antenna 6 has directivity in the direction of radiation of the electromagnetic wave, the opening of the waveguide is apparent. It is called a rotating waveguide because the part also appears to move.
The rotating antenna 6 is rotationally driven by a motor 7 as a second driving unit. Since the switch 8 as a position detecting unit is pressed somewhere in one rotation, the rotational position can be determined from the driving time after the switch 8 is pressed. In addition, it is possible to detect the direction of the radiation of the electromagnetic wave and to control the direction of the electromagnetic wave. The control unit 9 determines the rotation time of the motor 7 based on the signal from the switch 8 and controls the direction of the radiation of the electromagnetic wave from the rotating antenna 6. Of course, as for the rotation control of the motor 7, a stepping motor may be used when performing more precise position control or finer control such as changing the rotation speed.

The food 5 is placed on a glass or ceramic dish 11 formed on a metal turntable 10 for uniform heating, and is integrally rotated by a motor 12. At this time, the control unit 9 detects the weight of the food 5 with the weight sensor 13 which is the weight detection unit of the food 5 at the same time as the rotation of the motor 12 which is the first driving unit, and performs control (drive of the rotary antenna 6) accordingly. Timing, heating output, heating end time estimation, etc.). Further, the rotation center at this time is located at the center 14 of the bottom surface of the heating chamber 4, and the rotation is intended to make the heating in the rotation direction uniform. On the other hand, the center of rotation of the rotating antenna 6 is shifted from the center 14 of the bottom surface of the heating chamber 4. For the food 5, the direction of radiation of the electromagnetic wave changes depending on the direction of the rotary antenna 6, so that it is possible to switch between heating the center of the food 5 and heating the periphery of the food 5, so to speak, heating the turntable 10 in the radial direction. The site can be changed. In other words, the relative position between the food 5 and the direction of the electromagnetic wave radiation is detected by the switch 8,
This means that control is performed for appropriate heating.

In addition to the control described above, the control unit 9 monitors a temperature change of the food 5 by a temperature sensor 15 which is a temperature detecting unit for detecting the temperature of the food 5, radiates an electromagnetic wave from the magnetron 1, and controls the magnetron 1. 1 The operation of the cooling fan 16 and the operation of various heaters 17 are controlled.

Generally, when the heater 17 is used, the temperature in the heating chamber 4 rises to around 300 ° C., and since the heat resistance temperature of the dish 11 is limited to glass, the dish 11 is often replaced with a metal dish. In order to save the trouble of replacing the plate 11 depending on the application of the heating of the electromagnetic wave and the heating of the heater, the ceramic plate 11 having a high heat-resistant temperature may be used for both purposes.

The temperature sensor 15 is connected to the opening 1 in the wall of the heating chamber 4.
8, the temperature of the food 5 is detected.
A description will be given of its own configuration. As a general temperature sensor 15 that detects temperature in a non-contact manner, there is an infrared sensor that converts an amount of infrared radiation radiated from the food 5 into an electric signal. As the infrared sensor, there are a thermopile type having a hot junction and a cold junction therein, a pyroelectric type having a chopper, and the like, and either of them may be employed in the present invention.

Further, in general, in order to cover the opening into which the electromagnetic wave is incident, the heating chamber 4 is often covered with an opening cover made of a low-loss material that does not easily absorb the electromagnetic wave. 3 is configured to cover 3,
There is no unevenness compared to the bottom of the heating chamber 4.

As another embodiment, a case where the rotational position of the turntable 10 is detected by controlling the rotational position of the turntable 10 while the rotational antenna 6 is kept at a constant rotation, or a configuration in which the rotational position of both are controlled. As an example of detecting the rotational position of the turntable 10, a switch may be pressed somewhere in one rotation like the rotary antenna 6 and the switch 8 described above. Also, in either case of position detection, various embodiments are conceivable, such as a method of exchanging an optical signal for each rotation with an optical sensor by cutting a slit. Further, the rotary antenna 6 may be configured to reciprocate without rotating.

As another embodiment, a case where the power supply chamber 3 is not provided will be described. In this case, the rotating antenna 6 protrudes into the heating chamber 4, but it is also conceivable to provide a cover for covering the same. This cover is a cover 19
Unlike this, it is conceivable that the rotating antenna 6 is formed in a box shape so as to protect it, or the entire bottom surface portion of the heating chamber 4 is covered like a cover 31 in FIG.

FIGS. 2 and 3 are cross-sectional views of the main parts of the high-frequency heating apparatus according to one embodiment of the present invention, and are AA 'in FIG.
It shows a cross section. With respect to the direction (directivity) of the rotating antenna 6, FIG. 2 is the same as in FIG. 1 and is directed to the center, and FIG.

FIG. 2 shows the electromagnetic wave emission port 20 of the rotary antenna 6.
Are directed to the rotation center of the turntable 10, that is, the center of the heating chamber 4, and the electromagnetic wave 21 is emitted toward the center.
Here, the central portion 22 of the bottom surface of the heating chamber 4 protrudes upward, and for example, even if water is spilled, the turntable 10
, So as not to leak below the heating chamber 4. The front of the heating chamber 4 is closed by an openable and closable door 23 for taking in and out the food 5.

FIG. 3 shows an electromagnetic wave emission port 20 of the rotary antenna 6.
Are directed in the opposite direction to the rotation center of the turntable 10, that is, outside the heating chamber, and the electromagnetic waves 21 are emitted outward.

FIG. 4 is a schematic view of a main part of a high-frequency heating apparatus according to one embodiment of the present invention, and is a view of the bottom surface of the heating chamber 4 of FIG. 1 as viewed from below. Heaters 17A, 17B, 17C are provided in the empty space so that they can coexist with the power supply chamber 3 and the weight sensor 13.
Has been arranged.

FIG. 5 is a schematic diagram of a high-frequency heating device according to one embodiment of the present invention, showing the configuration of the turntable 10 as viewed from below. The turntable 10 is made of metal and includes wheels 24A and 24B, shafts 25A and 25B, and a rotary bearing 26. The distances L1 and L2 in the rotation direction of the gap of the turntable 10 are each １ ／ of the wavelength of the electromagnetic wave.
It has the above-mentioned length, and has a configuration in which electromagnetic waves can be easily transmitted.

FIG. 6 is a view showing the configuration of a main part of a high-frequency heating apparatus according to another embodiment of the present invention, and shows the configuration of the turntable 10 as viewed from below. Turntable 1 unlike FIG.
Numeral 0 is made of a material which is hard to absorb electromagnetic waves such as ceramics and has transparency, and is composed of a disk 27 and a rotary bearing 26. The configuration is such that electromagnetic waves can be easily transmitted even if there is no gap.

When an electromagnetic wave is applied from below, the turntable 10 passes through the electromagnetic wave and is a microwave oven using a heater 17, so that the heat table is highly heat-resistant by contriving the turntable 10 as shown in FIGS. It is configured to easily transmit electromagnetic waves.

FIG. 7 is a cross-sectional view of a main part of a high-frequency heating device according to another embodiment of the present invention, showing the dimensional relationship between the turntable 10 and the central portion 22 of the bottom surface of the heating chamber 4. The turntable 10 has a radius r (2r in FIG. 7).
And the protrusion dimension of the central part 22 on the bottom surface of the heating chamber 4 is radius R
(2R in FIG. 7) and 2R> 2r, that is, R> r
In a relationship. Therefore, even if water is spilled on the turntable 10, for example, the shaft of the turntable 10 does not leak below the heating chamber 4 along with the axis of the turntable 10. Since water accumulates on the outside of the 2R, wiping work can be performed without removing the turntable. In particular, as shown in FIG.
In the case where 0 is made of ceramic, it is generally said that the ceramic has low strength, and there is a problem of durability such as cracking due to repeated attachment / detachment work to the rotating shaft. Therefore, with the configuration as in the present embodiment, there is no need to attach or detach it during cleaning, and there is an effect that durability can be maintained.

FIGS. 8 and 9 are cross-sectional views of the essential parts showing the actual heating distribution in the configuration of FIGS. Rotating antenna 6
In order to show the directivity of the above, the results are shown when the food 5 having a flat and rectangular parallelepiped shape is heated by an electromagnetic wave while the turntable 10 and the rotary antenna 6 are stopped at the positions in the figure. However, for the sake of simplicity, the part that is actually hidden behind the plate 11 and cannot be seen is also indicated by a solid line.

In FIG. 8, the heating portion 28 appears at the approximate center of the food 5 due to radiation from below the electromagnetic wave 21.

In FIG. 9, since the electromagnetic wave 21 enters the food 5 after being reflected on the wall surface of the heating chamber 4, the heating section 28 appears at the edge (around) of the food 5. In the conventional microwave oven, in most cases, a result similar to that in FIG. 9 is often obtained because the electromagnetic wave is reflected on the wall of the heating chamber 4 before entering the food. Of course, in this case, when the turntable 10 is rotated, the food 5
It is clear that only the edges of the are heated.

From the above results, it can be seen that uniformity of heating can be achieved by switching between the states shown in FIGS. 8 and 9 (switching the direction of the rotating antenna 6 at an appropriate ratio).

FIGS. 10 to 19 are characteristic diagrams comparing a conventional microwave oven with the present invention. First, FIGS. 10 to 13 show an example in which the food 5 at room temperature (20 ° C.) is warmed and reheated.

FIG. 10 is a characteristic diagram when a conventional microwave oven is used as usual. The horizontal axis represents the heating time t, and the vertical axis represents the food 5.
Is shown. Food 5 similar to that used in FIGS. 8 and 9
The average temperature of the peripheral portion of the food 5 was roughly expressed by Tout, the average temperature of the central portion was generally expressed by Tin, and the target average temperature Tref at the end of heating was 80 ° C. When the heating starts, as described in FIG. 9, Tout quickly rises and Ti
n does not rise easily. Tout is Tref after t1
, And the temperature reaches the saturation temperature (boiling temperature) after t2. However, if heating is terminated at that point, there is a problem that the temperature of Tin is too low. Therefore, heating is continued until the time t3 at which Tin becomes a permissible range, and finally the heating is completed. At this time, the peripheral portion of the food 5 is overheated (Tout> Tref), and the central portion is insufficiently heated (Ti
The result is very poor because n <Tref).

On the other hand, FIG. 11 is a characteristic diagram of one embodiment of the present invention, in which the direction of the rotary antenna 6 is switched halfway to achieve uniform heating. First, at the start of heating, the direction of the rotating antenna 6 is set to the same configuration as in FIG. 8, and the center portion of the food 5 is heated first, and at t4, the direction of the rotating antenna 6 is rotated by 180 ° to the same configuration as in FIG. It is the one that has been switched. When the heating starts, Ti
n rises in temperature quickly and Tout does not rise easily,
After time t4, the temperature rise rate reverses, and Tout is more likely to rise than Tin. Therefore, if the heating is finished at t5, both the peripheral portion and the central portion of the food will be in a very good heating state (ToutｕTin ≒ Tref), and the finish is very good. Also, at this time, since there is no excessive heating, there is little heating loss and the heating can be completed in a short time (t5 <t3).

FIG. 12 is a characteristic diagram showing how the switching timing of the rotary antenna 6 in FIG. 11 is determined. The horizontal axis is the weight m of the food 5 detected by the weight sensor 13, and the vertical axis is the time t. Since the optimal heating time becomes longer as the weight of the food 5 increases, there is a method in which the switching time t4 of the rotating antenna 6 is calculated and calculated in the control unit 9 as a function of m. Of course, the heating end time t5 can be similarly determined.

Of course, as shown in FIG.
There is also a method of performing feedback control based on the temperature of the food itself instead of determining the switching timing of the food by weight. This is slightly different from FIG.
Is monitored in real time, and when Tin reaches Tk (Tk is lower than Tref), the rotating antenna 6 is switched. Further, the temperature is continuously monitored thereafter, and control is performed so that the heating is ended at the moment t6 when the temperature of the food 5 actually reaches Tref. The temperature of the food 5 is actually measured by the temperature sensor 15, and it can be said that the accuracy is higher than the estimation based on the weight m.

In contrast to the above, it is needless to say that the switching need not be limited to one time, and it may be better to perform the switching several times because the temperature difference is less likely to spread.

Further, in order to realize uniform heating without any irregularity in the distribution of heating, no matter what kind of food 5 is used, it is necessary to optimize the food 5 in advance in accordance with conditions such as the material, shape, position and temperature of the food 5. There is a method in which information such as the direction of the rotating antenna 6 and switching timing is stored in a microcomputer in the control unit 9 in advance as a database. In this embodiment, by this method, the control unit 9 controls the temperature sensor 15
By comparing the output from the weight sensor 13 and the database with the database, control for optimal heating can be performed.

Next, FIGS. 14 to 19 show a frozen state (−20 ° C.).
This is an example of the case where the food 5 is thawed.

First, FIG. 14 shows the dielectric loss εr · tan δ of water.
FIG. 4 is a temperature characteristic diagram of FIG. The horizontal axis indicates the water temperature T, and the vertical axis indicates the dielectric loss εr · tan δ. It can be seen that frozen water (ice below 0 ° C.) has a small dielectric loss, and rises extremely to molten water (0 ° C. or more) (it increases drastically about 10,000 times). On the other hand, the power absorbed per unit volume by the electromagnetic wave is proportional to εr tan δ as shown in equation (1). Therefore, the melted part becomes extremely easy to absorb electromagnetic waves, and if the heating is continued as it is, the part where thawing is progressing is heated more and the temperature difference is further enlarged. That is, if heating of the electromagnetic wave is continued with the heating distribution as it is in a state where a part of the water is dissolved, temperature unevenness is inevitably generated.

FIGS. 15 and 16 are characteristic diagrams of a conventional microwave oven. FIG. 15 is a characteristic diagram showing a change in heating output due to electromagnetic waves when the frozen food 5 is thawed. The horizontal axis indicates time t, and the vertical axis indicates output P. During the initial heating time t7, the heating is performed at a continuous high output. During the time t8, the output is reduced and the operation is switched to the intermittent operation. During the last t9, the intermittent ratio is further changed to obtain an average output. I'm pulling it down. Simply put, the output is gradually reduced.
By lowering the output, the temperature rise due to the heating of the electromagnetic wave is reduced, and the rate of temperature rise due to the heat transfer inside the food 5 and the difference between the food 5 and the ambient temperature in the heating chamber 4 is increased, so that the temperature unevenness is slightly improved. Has the effect of doing

FIG. 16 is a characteristic diagram showing how t7, t8, and t9 in FIG. 15 are determined. The horizontal axis is weight m
And the vertical axis is time t. Here, as a function of the weight m of the food 5 detected by the weight sensor 13, t7, t8,
t9 has been decided. The problem in this case is that the output switching timing is determined only by m regardless of the storage state of the food 5 before heating. For example, if the storage temperature before heating is high, there is a possibility that a part of the mixture will be melted and boiled before t7. Therefore, actually, the temperature sensor 15
Should be corrected by the output of Of course, it is still the same that heating is performed with a constant heating distribution, so that it is not expected to eliminate temperature unevenness much.

FIGS. 17 to 19 are characteristic diagrams of a high-frequency heating device according to another embodiment of the present invention. FIG. 17 is a temperature characteristic diagram when the frozen food 5 is thawed. The horizontal axis is time t, and the vertical axis is temperature T. First, the direction of the rotating antenna 6 is stopped toward the center as shown in FIGS. 2 and 8, and heating is started. The set temperature Tk = 0 ° C. described in FIG.
The heating is stopped at time t10 when in = Tk is reached, and at the same time, the rotating antenna 6 is turned outward as shown in FIGS.
After that, it waits for Tout in the low temperature part to rise to some extent without emitting an electromagnetic wave for ts, and then starts heating again from t11. At this time, since the direction of the rotating antenna 6 has changed, the heating portion is on the peripheral side, and the temperature rise of Tout is faster and catches up with Tin. And Tin ≒
The heating is terminated at time t12 when Tout 加熱 Tref. As a result, the effect of averaging the temperature due to the waiting time ts and the effect of switching the heating distribution by the rotating antenna 6 can achieve a very good defrosting without uneven distribution.

FIG. 18 shows ts or t11, t in FIG.
12 is a characteristic diagram showing how to determine No. 12; FIG. The horizontal axis is weight m and the vertical axis is time t. Here, t is a function of the weight m of the food 5 detected by the weight sensor 13.
s, t11 and t12 are determined. Of course, there is a method of determining the temperature while correcting the output from the temperature sensor 15, and it is considered that the accuracy of the uniform heating is further improved.

FIG. 19 is a characteristic diagram showing a change in heating output due to electromagnetic waves when the frozen food 5 described in FIGS. 17 and 18 is thawed. The horizontal axis indicates time t, and the vertical axis indicates output P. During the initial heating time t10, the heating is performed at a continuous high output. After that, no output is output during the time ts, and the output is reduced until the last t12, and the average output is reduced by switching to the intermittent operation. I have.

Further, in the present embodiment, the rotating antenna 6 is driven when the heating by the electromagnetic wave is stopped, which is compared with the conventional stirring of the electromagnetic wave of a constant rotation such as a stirrer or a rotating waveguide. This has the effect of suppressing unnecessary radiation and an increase in the temperature of the magnetron 1.

[0079]

As described above, the high-frequency heating device of the present invention has the following effects.

(1) Electromagnetic wave radiated from electromagnetic wave radiating section
Is a turntable via a waveguide and a feed port switching unit.
Of the heating chamber from below
Is a metal or conductive material that has a gap through which electromagnetic waves can pass.
Made of conductive material, electromagnetically close from the bottom of the object to be heated
Will radiate waves, and most of the emitted electromagnetic waves
Is absorbed by a portion of the object to be heated that is close to the radial direction. Immediately
That is, the direction of the electromagnetic wave matches the heated portion as it is. Next
In turn, the turntable uses the first drive unit to
It can be mounted and rotated. Power supply switching
Unit turns the direction of the electromagnetic wave by the second drive unit.
Change from the center of the bull to a predetermined position on the outer edge
it can. Therefore, the turntable and the power supply
Electromagnetic waves can be applied to any part of the object
You can turn around. Further, the control unit detects the position.
Based on the radiation direction of the electromagnetic wave before the start of heating detected by the part,
The radiation amount of the electromagnetic wave from the electromagnetic wave radiation unit, the first driving unit and
Since the second drive unit is controlled individually,
Can emit any amount of electromagnetic waves to the site of
Operate the object to be heated evenly, or
Can be operated to heat the minutes intensively.
Wear. Therefore, there is an effect that a heating distribution according to the purpose can be realized for the object to be heated, such as local heating for intensively heating a specific portion or uniform heating for uniformly heating all portions. As a typical high-frequency heating device, when cooking in a microwave oven, a single item of food can be heated evenly, or various types of food can be selectively heated (for example, boiled and fried foods can be heated on a single plate). Raw vegetables are not heated). In addition, if the portions that do not need to be heated are not heated, the heating effect can be improved and the speed can be increased, and power consumption can be suppressed and energy can be saved.

(2) Turntable is metal or conductive
Made of conductive material, more than half the wavelength of electromagnetic waves in the direction of rotation
The gap has a length of
It can easily penetrate up and down through the gap. Yo
Of the heated object by the turntable
The heating part can be switched. Also turntabes
Has high heat resistance and is a popular type with an oven function.
When the heater is configured below the bottom of the heating chamber like a small range
Can also be used.

(3) Electromagnetic wave radiated from the electromagnetic wave radiating section
Is a turntable via a waveguide and a feed port switching unit.
Of the heating chamber from below
Is made of a material that transmits electromagnetic waves.
Electromagnetic waves will be emitted from the surface in close proximity,
Most of the electromagnetic waves that are emitted
It is absorbed in the place. In other words, the direction of the electromagnetic wave is
Matches the rank. Next, the turntable is driven by the first drive unit.
Thus, the object to be heated can be placed and rotated. Ma
The power supply port switching unit is configured to transmit the electromagnetic wave by the second driving unit.
Predetermine the direction from the center of the turntable to the outer edge
Can be changed to the specified position. Therefore turntable and power supply
Combination with the mouth switching section allows for
The direction of the electromagnetic wave can be directed to the portion where the electromagnetic wave is generated. further,
The control unit releases the solenoid valve before the start of heating detected by the position detection unit.
The amount of electromagnetic radiation from the electromagnetic radiation
Since each controls the first drive unit and the second drive unit,
Emit any amount of electromagnetic radiation to any part of the object to be heated
Can be Therefore, the object to be heated is uniformly heated.
Or to heat specific parts intensively.
Can work. Therefore, (1) the same effect
is there

(4) The power supply port switching unit controls the direction of the electromagnetic wave.
Because it changes continuously, it can be
There is no direction in which electromagnetic waves cannot be emitted,
The direction can be switched at intervals. Therefore (1),
There is an effect that the effect of (3) can be maximized.

(5) Since the electromagnetic wave is guided to the heating chamber via the power supply chamber and the power supply port switching unit is provided in the power supply chamber, (i) connecting the waveguide and the heating chamber with the power supply chamber Thus, there is an effect that the reflection of the electromagnetic wave can be easily suppressed and the matching can be easily obtained.

Ii) Since the power supply port switching section does not protrude into the heating chamber, and especially when the power supply port switching section is covered so that the user does not touch it, the bottom surface of the heating chamber including the cover can be flattened. This has the effect that the user can easily clean the heating chamber.

Iii) When a cover is provided for the power supply port switching unit, the size of the cover is sufficient to cover the power supply chamber without covering the entire bottom surface of the heating chamber, and the cover can be reduced in size and cost. .

(6) Since the inside of the circle of radius R where R> r has a convex slope on the bottom of the heating chamber around the center of rotation of the turntable of radius r, the liquid is placed above or around the turntable. When the object to be heated is spilled, cleaning can be performed without removing the turntable.

(7) Since the direction of the electromagnetic wave is directed to the center of the bottom surface of the heating chamber after the start of heating by the power supply port switching section on the bottom of the heating chamber, the center of the object to be heated is mainly heated, and then the direction of the electromagnetic wave is changed to the heating chamber. Since it is directed to the outside of the bottom surface, the periphery of the object to be heated is mainly heated, so that uneven heating can be reduced.

(8) The power supply port switching unit is driven before the object to be heated is partially heated by the output of the detection unit for detecting the physical quantity of the object to be heated and the state of the inside of the heating chamber. It has the effect of suppressing uneven heating by switching parts.

(9) When the object to be heated in a frozen state is to be thawed, the object to be heated is continuously irradiated with electromagnetic waves in a range where the maximum temperature of the object to be heated is estimated to be 0 ° C. or lower, and the maximum temperature is 0 ° C.
Is controlled to temporarily stop the emission of electromagnetic waves when it is estimated that it has exceeded the threshold. Therefore, there is an effect that the expansion of the temperature difference after the maximum temperature exceeds 0 ° C. is suppressed, and the temperature unevenness is reduced by heat conduction in the object to be heated during the stop time. Thus, a thawed finish with less uneven heating can be provided.

(10) Since the power supply port switching unit is driven when the emission of the electromagnetic wave is stopped, the electromagnetic waves in the heating chamber are not agitated by driving the power supply port switching unit.
Therefore, since the electromagnetic wave radiating portion can be used in a stable operation region, unnecessary radiation and an increase in the temperature of the electromagnetic wave radiating portion are suppressed, and noise countermeasures and a cooling configuration can be simplified.

(11) Since the suspension time of the radiation of the electromagnetic wave is determined by the output of the detecting unit, the heat conduction inside the object to be heated or the heat transfer between the object to be heated and the inside of the heating chamber are determined according to the state of the object to be heated or the inside of the heating chamber. The rate of temperature rise due to the difference from the ambient temperature can be determined. Therefore, appropriate heating can be performed so as to suppress uneven thawing of the object to be heated. (12) Since the detection unit is constituted by at least one of the temperature detection unit and the weight detection unit, the state of the object to be heated can be easily estimated with a simple configuration. Therefore, it can be realized with a simple and low-priced configuration, and has a high reliability as is clear from past results.

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration diagram of a high-frequency heating device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional configuration diagram of the high-frequency heating device.

FIG. 3 is a cross-sectional configuration diagram of the high-frequency heating device.

FIG. 4 is a configuration diagram of a main part of the high-frequency heating device.

FIG. 5 is a configuration diagram of a turntable in one embodiment of the present invention.

FIG. 6 is a configuration diagram of a turntable according to another embodiment of the present invention.

FIG. 7 is a cross-sectional configuration diagram of a main part of the high-frequency heating device.

FIG. 8 is a sectional configuration diagram of the high-frequency heating device.

FIG. 9 is a sectional configuration diagram of the high-frequency heating device.

FIG. 10 is a characteristic diagram of a conventional high-frequency heating device.

FIG. 11 is a characteristic diagram of a high-frequency heating device according to an embodiment of the present invention.

FIG. 12 is a characteristic diagram of a high-frequency heating device according to an embodiment of the present invention.

FIG. 13 is a characteristic diagram of a high-frequency heating device according to another embodiment of the present invention.

FIG. 14 is a temperature characteristic diagram of dielectric loss of water.

FIG. 15 is a characteristic diagram of a conventional high-frequency heating device.

FIG. 16 is a characteristic diagram of a conventional high-frequency heating device.

FIG. 17 is a characteristic diagram of a high-frequency heating device according to an embodiment of the present invention.

FIG. 18 is a characteristic diagram of the high-frequency heating device.

FIG. 19 is a characteristic diagram of the high-frequency heating device.

FIG. 20 is a sectional view of a main part of a conventional high-frequency heating device.

FIG. 21 is a cross-sectional configuration diagram of a main part of another conventional high-frequency heating device.

FIG. 22 is a sectional configuration view of a main part of another conventional high-frequency heating device.

FIG. 23 is a cross-sectional view of a main part of another conventional high-frequency heating device.

FIG. 24 is a sectional configuration view of a main part of another conventional high-frequency heating device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetron (electromagnetic wave radiation part) 2 Waveguide 3 Power supply chamber 4 Heating chamber 5 Food (object to be heated) 6 Rotating antenna (power supply port switching part) 7 Motor (second drive part) 8 Switch (position detection part) 9 Control unit 10 Turntable 12 Motor (first drive unit) 13 Weight sensor (weight detection unit) 15 Temperature sensor (temperature detection unit) 22 Central part of bottom surface

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI H05B 6/68 320 H05B 6/68 320M 320N 6/72 6/72 A 6/74 6/74 E (72) Inventor Makoto Shibuya 1006 Kadoma, Kazuma, Kazuma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-5-144566 (JP, A) JP-A-5-326136 (JP, A) JP-A-3-173309 (JP) , A) Japanese Utility Model Application Sho 61-3695 (JP, U) Japanese Utility Model Application No. 1-129793 (JP, U) Japanese Patent Application No. 58-55633 (JP, B2) Japanese Utility Model Application No. Sho 62-40557 (JP, Y2)

Claims (12)

(57) [Claims] 1. A heating chamber for taking in and out an object to be heated, and a gap through which the object to be heated is placed and rotated so that an electromagnetic wave can pass therethrough.
A turntable made of a metal or a conductive material to be driven, a first drive section for driving the turntable, an electromagnetic wave radiating section for radiating electromagnetic waves, and a direction of electromagnetic waves radiating from below the turntable to the object to be heated. From the center of the turntable to the outer edge of the predetermined
Can be changed to the position , and heats the target part by proximity radiation
A power supply port switching unit, and a waveguide that guides an electromagnetic wave radiated from the electromagnetic wave radiation unit to the power supply port switching unit,
A second drive unit that drives the power supply port switching unit to change the direction of the electromagnetic wave, a position detection unit that detects the radiation direction of the electromagnetic wave before the start of heating, and the position detection unit depending on the radiation direction of the electromagnetic wave detected by electrodeposition from the electromagnetic wave radiating portion
The radiation amount of the magnetic wave, the first drive unit and the second drive unit
The a control section for controlling each of the object to be heated and electrostatic
By changing the relative position of the direction of the magnetic wave, the object to be heated is uniformly applied.
Operate to heat or intensively heat specific parts
High-frequency heating device to operate . 2. The turntable has a wave of electromagnetic waves in a rotating direction.
A structure having a gap having a length equal to or longer than 1/2 of the length.
2. The high-frequency heating device according to 1. 3. A heating chamber for taking in and out an object to be heated, and a material which is placed on the object to be heated and which rotates to transmit electromagnetic waves.
Wherein the turntable, a first driving unit for driving the turntable, and an electromagnetic wave radiating unit for radiating electromagnetic waves, the direction of the electromagnetic <br/> wave emitted to the object to be heated from below of the turntable that From the center of the turntable to the outer edge
Can be changed to a predetermined position , and aim by proximity radiation
A feed port switching unit for site capable of heating the that Tsu, a waveguide for guiding electromagnetic waves radiated from said electromagnetic wave radiation part to the feed port switching unit, wherein the electromagnetic driving the feed port switch part
A second drive to change the direction of the waves and an electromagnetic
A position detector for detecting the radial wave, depending on the radiation direction of the electromagnetic wave detected by said position detecting unit, the radiation amount of electromagnetic waves from the electromagnetic wave radiation part, the first drive unit and the front <br/> Symbol and a control unit for controlling the second driving portion, respectively, before
Change the relative position of the object to be heated and the direction of the electromagnetic wave, and
It can be operated to heat heating objects evenly, or
A high-frequency heating device that operates to heat intensively . 4. The power supply port switching section according to claim 1, wherein the direction of the electromagnetic wave is continuously changed .
2. The high-frequency heating device according to claim 1. 5. A waveguide guides an electromagnetic wave radiated from an electromagnetic wave radiating section to a heating chamber through a power supply chamber, and a power supply port switching section is provided in the power supply chamber and changes a direction of the electromagnetic wave entering the heating chamber. 5. A method according to claim 1, wherein
Item 1. The high-frequency heating device according to item 1 . 6. any one of the bottom surface of the heating chamber is within a circle of radius R R> r becomes about the rotation center of the turntable of the radius r claims 1 was configured to have an inclined convex upwards 5 1 Item 1. The high-frequency heating device according to item 1. 7. The control section directs the direction of the electromagnetic wave from the power supply port switching section toward the center of the bottom surface of the heating chamber immediately after the start of heating.
The high-frequency heating apparatus according to any one of claims 1 to 6 , wherein the second driving unit is controlled so as to be directed outside the bottom surface of the heating chamber. 8. A detecting section for detecting at least one of a physical quantity of the object to be heated or a variation thereof or a physical quantity indicating a state in the heating chamber or a variation thereof, and a heating progress state or an end time based on an output of the detection section. The control unit controls the second drive unit to drive the power supply port switching unit before the object to be heated is overheated partially. The high-frequency heating device according to any one of items 7 to 7 . 9. A detecting section for detecting at least one of a physical quantity of an object to be heated or a variation thereof or a physical quantity indicating a state in a heating chamber or a variation thereof, and a heating progress state or an end time based on an output of the detection section. Estimating at least one of the above, the control unit, when thawing the object to be frozen in a frozen state, continuously emits electromagnetic waves and heats in a range where the maximum temperature of the object to be heated is estimated to be 0 ° C. or less. And controlling the electromagnetic wave radiating unit to temporarily stop the radiation of the electromagnetic wave when it is estimated that the maximum temperature of the object to be heated exceeds 0 ° C.
9. The high-frequency heating device according to any one of items 8 to 8 . 10. The control unit according to claim 9, wherein the control unit controls the power supply port switching unit to be driven during a suspension time from when the emission of the electromagnetic wave is temporarily stopped to when the next emission is started. High frequency heating device. 11. The high-frequency heating apparatus according to claim 9, wherein a temporary stop time from when the emission of the electromagnetic wave is temporarily stopped until when the next emission is started is determined by an output of the detection unit. 12. The apparatus according to claim 8, wherein the detecting section comprises at least one of a temperature detecting section for detecting the temperature of the object to be heated and a weight detecting section for detecting the weight of the object to be heated. The high-frequency heating device as described.