JP4935188B2 - Microwave equipment - Google Patents

Description

  The present invention relates to a microwave utilization apparatus that dielectrically heats an object to be heated using a microwave generating means having a frequency variable function.

  Conventionally, there is a microwave oven as a microwave heating device as a typical microwave utilization device of this type. A magnetron as a microwave generating means mounted on the microwave oven has a high output with respect to its shape and a high operating efficiency of more than 70%.

  On the other hand, the magnetron cannot freely control the oscillation frequency, and the oscillation frequency of the magnetron itself is influenced by the impedance on the load side including the object to be heated. For this reason, the object to be heated may be unevenly heated due to the standing wave generated in the heating chamber due to the operation at an inappropriate oscillation frequency.

  There are coaxial magnetrons and the like that variably control the oscillation frequency of the magnetron, but they are not suitable for microwave oven applications due to their large shape and high price.

  On the other hand, microwave circuit technology using semiconductor elements has progressed due to the advancement of vigorous microwave circuit technology accompanying the recent development of mobile communications, or the technological innovation of semiconductor elements themselves using new semiconductor materials such as SiC materials and GaN materials. Wave generation means are beginning to be put into practical use in plasma processing apparatuses used for semiconductor manufacturing.

  The microwave generating means constituted by this semiconductor element can easily control the oscillation frequency variably by using a voltage controlled oscillator or a capacitance controlled oscillator as an oscillation source. There is one that uses a frequency self-excited solid-state oscillating unit and controls the oscillation frequency according to the impedance of the power feeding portion to the heating chamber to form an optimum matching state and efficiently heat (for example, Patent Documents) 1).

  Also, there is a technique in which a plurality of radiation antennas are provided, and the radiation antenna is selectively operated on the basis of reflected microwaves from the object to be heated to increase heating efficiency (see, for example, Patent Document 2).

This apparatus is provided with a transmission / reception selector switch for each radiation antenna, and can detect the amplitude and phase information of the reflected wave received from the heated object side. Based on this detection information, heating is efficiently performed by stopping microwave transmission to a radiation antenna that is inefficient for heating.
JP 59-165399 A JP 2000-357583 A

  However, controlling the oscillation frequency and matching the impedance of the power feeding part is to search the resonance state of the heating chamber and find the frequency, and the resonance state generated in the heating chamber is not necessarily one, There is a problem that the frequency extracted by searching cannot always effectively and uniformly heat the object to be heated.

  Also, a method of arranging a plurality of radiation antennas and selecting a radiation antenna to be operated based on reflected wave information from each radiation antenna according to the object to be heated is from the viewpoint of heating the object to be heated from many directions. Although it will contribute to the promotion of homogenization, a specific standing wave is generated in the heating chamber by the radiated microwave, so that a heated distribution due to the specific standing wave is added to a thick object to be heated. There is a problem that the uniformity of heating is hindered.

  The present invention has been made in view of such circumstances, and provides a microwave utilization apparatus that uses both microwave generation means capable of changing the frequency and achieves both uniform heating of the object to be heated and high heating efficiency. For the purpose.

  In order to solve the above-described conventional problems, the microwave utilization apparatus of the present invention includes a heating chamber in which an object to be heated is stored, and a microwave generation unit with a frequency variable function that generates a microwave to be supplied to the heating chamber. A plurality of radiating means for radiating microwaves to be supplied to the heating chamber; a plurality of switching means operating by energy of respective reflected waves reflected from the radiating means toward the microwave generating means; and the microwave generating means And a control means for variably controlling the frequency at which the radiation occurs, and the radiating means is selected by the operation of the switching means associated with the variable frequency.

  As a result, during the search for the optimum frequency for heating the object to be heated, the switching means is automatically operated by the energy of the reflected wave reflected from each radiating means, and the oscillation frequency is set so as to minimize the number of switching means that operate. By variably controlling, the microwave generated by the microwave generating means can be supplied to the heating chamber with maximum efficiency.

In addition, since the microwave radiation from the radiation means having a large reflected wave is automatically interrupted in the process of changing the oscillation frequency of the microwave generation means, most of the microwave supplied to the heating chamber is covered. It effectively acts on the heating of the heated object, so that the heating efficiency can always be kept high.

  The microwave utilization apparatus of the present invention can provide an apparatus that uses both microwave generation means capable of changing the frequency and achieves both uniform heating of an object to be heated and high heating efficiency.

The first invention comprises a heating chamber in which an object to be heated is stored, a plurality of radiating means for radiating microwaves to be supplied to the heating chamber, an oscillating unit using a semiconductor element, and an amplifying unit. A microwave generating means with a variable frequency function configured to output microwaves to be transmitted to the plurality of radiating means, and the amplifying section operated by respective reflected power reflected from the radiating means to the amplifying section side A plurality of switching means provided on the driving power supply line, and a control means for variably controlling the oscillation frequency generated by the microwave generating means at predetermined time intervals and steps, and the frequency variable control of the control means by operating said switching means by the reflected power exceeds a predetermined amount due to operation, the drive power supply of the amplifier connected to the radiation unit of the target is stopped, the driving electric of the amplifying section Frequency variation control even after the supply is stopped continues, reflected power is intended to perform the heating of the object to be heated is the drive power supply to the amplifying part and below a predetermined value, thereby the microwave generating means In the process of changing the oscillation frequency, microwave radiation from the radiation means having a large reflected wave is automatically interrupted, so most of the microwave supplied to the heating chamber is effective for heating the object to be heated. It is possible to maintain high heating efficiency at all times and perform heating by changing the frequency over the entire variable band, so that the generation of standing waves in the heating chamber can be avoided. Uniform heating can be promoted.

  The microwave generating means is composed of an oscillating unit and an amplifying unit using a semiconductor element, and includes a parallel operation amplifying unit that outputs microwaves to be transmitted to a plurality of radiating units. The radiating means and the amplifying unit can act as a pair, and the abnormal amplification operation by the reflected wave can be avoided by controlling the operation of the amplifying unit connected to the radiating means having a large reflected wave during the variable microwave frequency control. Further, it is possible to avoid damage to the amplification unit.

The second invention comprises a heating chamber in which an object to be heated is accommodated, a plurality of radiating means for radiating microwaves to be supplied to the heating chamber, an oscillating unit using a semiconductor element, and an amplifying unit. A microwave generating means with a frequency variable function configured to output microwaves to be transmitted to each of the plurality of radiating means, and microwave reflected power transmitted from each of the plurality of radiating means to the amplifying section side. Means for detecting, and control means for variably controlling the oscillation frequency generated by the microwave generating means at predetermined time intervals and steps, and the control means is configured to perform the reflection while the frequency variable control is in operation. A voltage signal proportional to the amount of reflected power detected by the means for detecting power is received, the input voltage signal is compared with two reference levels, and the reflected power exceeding the first predetermined amount is obtained. That when lowering the connected drive voltage of the amplifier to the radiating means of the subject, the drive power supply of the first amplification unit connected to the radiation unit of the target if it exceeds a second predetermined amount greater than a predetermined amount The frequency variable control continues even after the drive power supply control of the amplification unit, and the heating power of the object to be heated is controlled by controlling the drive power of the amplification unit according to the amount of reflected power detected after the variable control. As a result, the operation of the amplifying unit connected to the radiating means having a large reflected wave can be operated according to the amount of reflected power at the time of variable frequency control, and abnormal operation or thermal destruction of the semiconductor element of the amplifying unit can be prevented. The object to be heated can be uniformly heated by continuing the radiation from the plurality of radiation means while avoiding the problem.

The third aspect of the invention is particularly the microwave utilization apparatus of the first or second aspect of the invention, wherein there are a plurality of frequency variable function-equipped microwave generation means, and the oscillation frequency generated by each of the microwave generation means is a predetermined value. It has a configuration having a plurality of control means for variably controlling with time intervals and steps.

  The fourth aspect of the invention is the microwave utilization device of any one of the first to third aspects of the invention, wherein the control means takes in a signal as to whether or not power is supplied to each amplification unit, and the amplification When all the units are operating, the frequency variable speed is decreased, and when all the amplifying units are not operating, the frequency variable speed is increased.

  In the fifth invention, in particular, the plurality of radiating means of any one of the first to third inventions are configured to radiate microwaves in the direction of the placing means for placing the object to be heated. As a result, microwaves can be directly incident on the object to be heated to promote heating.

  In the sixth invention, in particular, the plurality of radiating means of any one of the first to third inventions have different resonance frequencies, and in the process of performing the variable frequency control, the reflected power There can be little radiation means and heating can be performed continuously.

In the seventh invention, in particular, the plurality of microwave generating means of the third invention are configured such that the oscillation frequencies of the respective oscillation units do not overlap, thereby allowing the frequency variation of the plurality of generation sources to proceed simultaneously. By supplying microwaves with different frequencies into the heating chamber and performing heating, generation of standing waves in the heating chamber can be avoided and uniform heating of the object to be heated can be further promoted. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited by this embodiment.

(Embodiment 1)
FIG. 1 is a block diagram of the microwave utilization apparatus according to the first embodiment of the present invention, and FIG. 2 is a block diagram of the microwave generating means of FIG.

  1 to 2, a heating chamber 10 for storing an object to be heated is provided with a door (not shown) through which the object to be heated is taken in and out, and other wall surfaces are made of a metal material and supplied. The microwave is confined inside. A placement plate 12 made of a low dielectric loss material on which the object to be heated is placed at a predetermined interval from the heating chamber bottom wall surface 11 is disposed below the heating chamber 10. Further, the left and right wall surfaces of the heating chamber 10 form wall surface regions 13 and 14 that are drawn in the inner and outer directions of the heating chamber 10 and are inclined toward the mounting plate 12.

  Metal wall surfaces 15 and 16 that respectively cover the inclined wall surface regions 13 and 14 from the outside of the heating chamber 10 are provided, and the waveguide wall shapes 17 and 18 are constituted by the inclined wall surface region and the metal wall surface. In addition, rectangular openings 13a and 14a, which are radiating means, are arranged at substantially the center of the inclined wall surface regions 13 and 14, respectively.

  Below the heating chamber 10, a microwave generation means 19 configured using a semiconductor element is disposed. The microwave generation means 19 includes an oscillation unit 20 having a voltage variable type frequency variable function, a first stage amplification unit 21 that primarily amplifies the output of the oscillation unit 20, and a distribution unit that distributes the output of the first stage amplification unit 21 into two. 22 and main operation amplifying units 23 and 24 in parallel operation for amplifying the distributed microwaves, respectively. The outputs of the main amplifying units 23 and 24 are transmitted through the coaxial lines 25 and 26 and guided to the waveguides 17 and 18. The microwaves guided to the waveguides 17 and 18 are radiated from the openings 13 a and 14 a toward the mounting plate 12 in the heating chamber 10.

The two outputs of the microwave generation means 19 are respectively connected to a power combiner 2 for extracting reflected power.
7 and 28 are arranged. Further, a driving power source 29 for the oscillation unit 20, a driving power source 30 for the first stage amplifying unit 21, driving power sources 31 and 32 for the main amplifying units 23 and 24, and control means 33 for controlling the operation of these driving power sources are arranged. Further, switching means 34 and 35 for supplying or stopping power are arranged on the power supply lines to the main amplifiers 23 and 24 of the drive power supplies 31 and 32.

  The power combiners 27 and 28 have a degree of coupling of about 10 dB and extract about 1/10 of the reflected power. The power signals are rectified by the detection diodes 36 and 37 and smoothed by the capacitors 38 and 39, respectively. Switching means 34 and 35 are connected to one end of the capacitors 38 and 39 via resistors 40 and 41. The resistors 42, 43, and 44 are resistors that cause heat loss of the transmitted power signal.

  Further, a heat dissipating means 45 for dissipating heat generated from the microwave generating means 19 is provided.

  About the microwave utilization apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  First, an object to be heated is stored in the heating chamber 10, the heating condition is input from an operation unit (not shown), and a heating start key is pressed. In response to the control signal of the control means 33 that has received the heating start signal 46, the microwave generation means 19 starts its operation. The control unit 33 operates the drive power supply 29 to supply power to the oscillation unit 20. At this time, the initial oscillation frequency of the oscillation unit 20 is supplied with a voltage signal set to 2450 MHz, for example, and oscillation starts. Thereafter, the drive power supply 30 is operated to operate the first stage amplifier 21, and then the drive power supplies 31 and 32 are operated to operate the main amplifiers 23 and 24, respectively. Thereby, each main amplification part 23 and 24 outputs the microwave electric power of 200W to 300W, respectively.

  The microwaves are transmitted through the coaxial lines 25 and 26, guided to the waveguides 17 and 18, and radiated from the openings 13a and 14a in the direction in which the object to be heated is placed. Part of the microwave radiated into the heating chamber 10 directly enters the object to be heated and is absorbed by the object to be heated, and the rest propagates through the heating chamber 10 while being repeatedly reflected by the wall surface of the heating chamber 10. If the microwave propagating in the heating chamber 10 has an object to be heated in the propagation path, the object to be heated further absorbs microwave energy. When 100% of the microwave energy supplied into the heating chamber 10 is absorbed by the object to be heated, the reflected power from the heating chamber 10 is lost, but the type, shape, and amount of the object to be heated include the object to be heated. 10 is determined, and based on the output impedance of the microwave generation means 19 and the impedance of the heating chamber 10, reflected power is transmitted from the heating chamber 10 side through the coaxial lines 25 and 26 in the reverse direction.

  The power couplers 27 and 28 combine the coaxial lines 25 and 26 with the reflected power signal transmitted to the microwave generating means 19 side, and the reflected power amount increases so that the voltage level for exciting the coils of the switching means 34 and 35 is obtained. When it reaches, the switching means operates to cut off the power supply to the associated main amplifying units 23 and 24. The control means 33 takes in a signal indicating whether or not power is supplied to the main amplifying units 23 and 24.

  Further, the control means 33 changes the oscillation frequency of the oscillation unit 20 at a predetermined time interval and step (for example, 1 MHz for 10 milliseconds). This frequency is increased from the initial 2450 MHz toward the upper limit value (for example, 2500 MHz), and when reaching the upper limit value, the frequency is decreased toward the lower limit value (for example, 2400 MHz). To do.

Due to this change in oscillation frequency, the amount of reflected power also changes, and when the reflected power exceeds a predetermined amount, the operation of the corresponding main amplification unit automatically stops, but by continuing the variable control of the frequency,
When the reflected power falls below a predetermined value, power is again supplied to the corresponding main amplification unit, the main amplification unit operates, and microwave energy is supplied to the heating chamber 10.

  With this operation, when the reflected power is large, the main amplifying unit stops operating, so that unnecessary power consumption can be avoided and the object to be heated can be heated with high heating efficiency. Further, by performing heating while changing the frequency over the entire variable band, it is possible to avoid the generation of standing waves in the heating chamber 10 and promote uniform heating of the object to be heated.

  Further, abnormal operation and thermal destruction of the semiconductor element of the main amplification unit due to the reflected power can be surely avoided, and a microwave generating means using a highly reliable semiconductor element can be provided.

  The variable frequency speed is slowed down when all the main amplifying units are operating (for example, 1 MHz per second), and when all the main amplifying units are stopped, the speed is changed. Various variable control methods such as increasing the speed (for example, 1 MHz in 2 milliseconds) may be adopted. Also, the frequency variable range may be selected and specified according to the object to be heated and heating conditions.

(Embodiment 2)
3-5 is a block diagram of the microwave utilization apparatus of the 2nd Embodiment of this invention.

This embodiment is different from the first embodiment in that the radiating means 50 and 51 have a resonance frequency and the main amplifiers 23 and 24 are based on the magnitude of the reflected power signal. The output voltages of the drive power supplies 52 and 53 are controlled. 3 to 5, components having the same configuration or substantially the same function as those of the first embodiment are denoted by the same reference numerals.

  In FIG. 3, waveguide shapes 17 and 18 are constituted by the inclined wall surface regions 13 and 14 formed on the left and right wall surfaces of the heating chamber 10 and the metal wall surfaces 15 and 16. Radiating means 50 and 51 having a resonance frequency are disposed on the inclined wall surface regions 13 and 14 on the heating chamber 10 side. The radiating means 50 and 51 are configured by vapor-depositing circular metal plates 50b and 51b on one side of a substrate 50a and 51a made of a low dielectric loss material in a substantially square shape, as shown in the top view of FIG. ing.

  The radiating means 50 is adjusted such that the resonance frequency is 2435 MHz, for example, and the resonance frequency of the other radiating means 51 is 2465 MHz, for example. In addition, the symbols “x” 50c and 51c in FIG. 4 indicate the positions where microwaves are fed to the respective circular metal plates 50b and 51b. One end is connected and fixed to this position, and the other end is in the waveguides 17 and 18. A metal rod extending to

  In addition, the metal wall surface of the inclined wall surface regions 13 and 14 is provided with a hole through which the metal rod penetrates. Further, the metal plate is deposited on the entire surface of the substrate 50a, 51a opposite to the circular metal plate. And the hole which penetrates a metal rod is arranged also in this metal plate vapor-deposited on the whole surface.

  Further, the radiating means 51 having a high resonance frequency is based on a circular metal plate having substantially the same diameter as the radiating means 50 having a low resonance frequency, and a line connecting the circular center and the feeding position 51c intersects the circular periphery. A notch 51d is provided on the edge of the circle with the point as a reference to increase the resonance frequency to a desired level.

  In FIG. 5, the directional couplers 54 and 55 extract a power amount of about 1/1000 of the reflected power with a degree of coupling of about 30 dB. The power signals are rectified by the detection diodes 56 and 57, smoothed by the capacitors 58 and 59, and input to the control means 60.

About the microwave utilization apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  First, an object to be heated is stored in the heating chamber 10, the heating condition is input from an operation unit (not shown), and a heating start key is pressed. In response to the control signal of the control means 60 that has received the heating start signal 61, the microwave generation means 19 starts its operation. The control unit 60 operates the drive power supply 29 to supply power to the oscillation unit 20. At this time, the initial oscillation frequency of the oscillation unit 20 is supplied with a voltage signal set to 2450 MHz, for example, and oscillation starts. Thereafter, the drive power supply 30 is operated to operate the first stage amplifier 21, and then the drive power supplies 52 and 53 are operated to operate the main amplifiers 23 and 24, respectively. Thereby, each main amplification part 23 and 24 outputs the microwave electric power of 200W to 300W, respectively.

  This microwave is transmitted to the waveguides 17 and 18 through the coaxial lines 25 and 26, and is emitted from the radiation means 50 and 51 in the direction in which the object to be heated is placed. Part of the microwave radiated into the heating chamber 10 directly enters the object to be heated and is absorbed by the object to be heated, and the rest propagates through the heating chamber 10 while being repeatedly reflected by the wall surface of the heating chamber 10. If the microwave propagating in the heating chamber 10 has an object to be heated in the propagation path, the object to be heated further absorbs microwave energy. When 100% of the microwave energy supplied into the heating chamber 10 is absorbed by the object to be heated, the reflected power from the heating chamber 10 is eliminated, but the type, shape, and amount of the object to be heated include the object to be heated. Based on the output impedance of the microwave generation means 19 and the impedance of the heating chamber 10, the reflected power that transmits the coaxial lines 25 and 26 in the reverse direction is generated from the heating chamber 10 side. .

  The directional couplers 54 and 55 combine the coaxial lines 25 and 26 with the reflected power signal transmitted to the microwave generation means 19 side, and input a voltage signal proportional to the reflected power amount to the control means 60.

  Further, the control means 60 outputs a frequency variable control signal similar to that described in the first embodiment to the drive power supply 29.

  Due to the change in the oscillation frequency, the amount of reflected power also changes. The control means 60 has two reference levels for comparing the signal corresponding to the input reflected power. When the reflected power exceeds a first predetermined amount that is one of the reference levels, the control means 60 performs control to reduce the output voltages of the drive power supplies 52 and 53 of the main amplifiers 23 and 24. As a result, the corresponding main amplifier section has a low amplification factor and a low output. Further, when the second predetermined amount larger than the first predetermined amount is exceeded, the control means 60 performs control so as to stop the operation of the drive power sources 52 and 53 of the main amplifying units 23 and 24. Regardless of such a change in the operation of the main amplification unit, the control means 60 continues the variable control of the frequency to output a control command corresponding to the reflected power signal level to the drive power sources 52 and 53, and to the drive power. Correspondingly, the main amplifying unit operates and microwave energy is supplied to the heating chamber 10.

  By this operation, the main amplifying unit is operated in accordance with the magnitude of the reflected power, so that abnormal operation and thermal destruction of the semiconductor element of the main amplifying unit due to the reflected power can be surely avoided, and the reliability is high. A microwave generation means using a semiconductor element can be provided. In addition, the main amplifying unit operates according to the magnitude of the reflected power, thereby avoiding unnecessary power consumption and heating the object to be heated with high heating efficiency. Furthermore, by performing heating by changing the frequency over the entire variable band, generation of standing waves in the heating chamber 10 can be avoided and uniform heating of the object to be heated can be promoted. .

(Embodiment 3)
FIG. 6 is a configuration diagram around the microwave generation means of the microwave utilization apparatus according to the third embodiment of the present invention.

  This embodiment is different from the first or second embodiment in that a plurality of oscillation sources are provided.

  That is, in FIG. 6, it has the microwave generation means 70 which is a 1st generation source, and the microwave generation means 71 which is a 2nd generation source, and each microwave generation means 70 and 71 is 1st. This is based on the configuration described in the embodiment. The difference is that the frequency variable ranges of the oscillation units 72 and 73 are configured to be variable ranges that do not overlap. That is, the frequency variable range of the oscillating unit 72 is, for example, 2400 to 2450 MHz, and the frequency variable range of the oscillating unit 73 is, for example, 2450 to 2500 MHz. In addition, a first control unit 74 and a second control unit 75 for controlling the driving power source of each microwave generation unit are arranged, and a control unit 76 for controlling the whole is arranged.

  The operation and action of the microwave utilization apparatus having a plurality of generation sources configured as described above will be described below.

  The control means 76 receives the heating start signal 77 and outputs an operation start signal to the first control means 74 and the second control means 75, and the microwave generation means 70 in accordance with the control signals from the control means 74 and 75. 71 start operation. The main amplifiers 78, 79, 80, 81 each output about 200 W of microwave power by a series of controls at the start of operation as described above. The initial oscillation frequencies of the oscillating units 72 and 73 are, for example, 2425 MHz and 2475 MHz, respectively. Further, the frequency variable is changed toward the upper limit of each variable range, then changed toward the lower limit, and further controlled to change toward the upper limit.

  The generated microwaves are transmitted through four coaxial lines, and are radiated from the four radiating means (not shown) into the heating chamber. At this time, microwaves having different frequencies propagate in the heating chamber. In addition, when the reflected power exceeds a predetermined value by the power couplers 82, 83, 84, 85 coupled to the reflected power transmitted in the reverse direction through the coaxial line from the heating chamber side, power is supplied to the target main amplification unit. Stops. Regardless of the change in the operation of the main amplifier, the control means 74 and 75 continue the variable control of the frequency, so that the main amplifier operates according to the reflected power level, and the microwave energy is heated. Supplied to the chamber.

  By this operation, when the reflected power exceeds a predetermined value, the operation of the target main amplification unit is stopped, so that abnormal operation or thermal destruction of the semiconductor element of the main amplification unit due to the reflected power can be surely avoided, and A microwave generating means using a highly reliable semiconductor element can be provided. In addition, the main amplifying unit operates according to the magnitude of the reflected power, thereby avoiding unnecessary power consumption and heating the object to be heated with high heating efficiency. Furthermore, by performing heating by supplying microwaves having different frequencies into the heating chamber, generation of standing waves in the heating chamber can be avoided, and uniform heating of the object to be heated can be further promoted.

  The radiating means can be used in various combinations with the radiating means described in the first and second embodiments. Further, for example, the radiating means may be arranged on the four wall surfaces on the left, right, and upper and lower sides. The variable speed of the frequency may be controlled differently for each oscillation source.

As described above, according to the present invention, by using the microwave generating means capable of changing the frequency, the microwave utilization device is configured to promote both uniform heating of the object to be heated and high heating efficiency. In addition to food heating such as commercially available microwave ovens, it can be applied to heating devices in industrial fields such as cleaning devices, drying devices, and semiconductor manufacturing devices.

Configuration diagram of microwave utilization apparatus of embodiment 1 of the present invention Configuration block diagram of microwave generation means of the microwave utilization apparatus The block diagram of the microwave utilization apparatus of Embodiment 2 of this invention Configuration diagram of radiation means of the microwave utilization device Configuration block diagram of microwave generation means of the microwave utilization apparatus Configuration block diagram of microwave generation means of Embodiment 3 of the present invention

10 heating chamber 12 mounting plate (mounting means)
13, 14 Inclined wall surface (inclined wall surface region)
13a, 14a Radiating means 19, 70, 71 Microwave generating means 20 Oscillator (variable frequency)
21, 23, 24 Amplifier 23, 24, 78, 79, 80, 81 Parallel drive amplifier 27, 28, 82, 83, 84, 85 Power combiner (coupled with reflected power)
33, 60, 74, 75, 76 Control means 34, 35 Switching means 50, 51 Radiation means with different resonance frequencies 54, 55 Directional coupler (coupled with reflected power)
72, 73 Oscillators whose oscillation frequencies do not overlap

Claims (7)

A heating chamber in which an object to be heated is stored;
A plurality of radiation means for radiating microwaves to be supplied to the heating chamber;
A microwave generating means with a frequency variable function configured to output a microwave to be transmitted to each of the plurality of radiating means;
A plurality of switching means provided on the drive power supply line of the amplifying unit that operates by each reflected power reflected from the radiating unit to the amplifying unit side;
Control means for variably controlling the oscillation frequency generated by the microwave generating means at predetermined time intervals and steps;
The switching means is operated by reflected power exceeding a predetermined amount accompanying the frequency variable control operation of the control means, the drive power supply of the amplification unit connected to the target radiation means is stopped , and the drive power supply of the amplification unit The variable frequency control continues even after the operation is stopped, and when the reflected power falls below a predetermined value, driving power is supplied to the amplifying unit to heat the object to be heated. A heating chamber in which an object to be heated is stored;
A plurality of radiation means for radiating microwaves to be supplied to the heating chamber;
A microwave generating means with a frequency variable function configured to output a microwave to be transmitted to each of the plurality of radiating means;
Means for detecting microwave reflected power transmitted from each of the plurality of radiating means to the amplifying unit side;
Control means for variably controlling the oscillation frequency generated by the microwave generating means at predetermined time intervals and steps;
During the operation of the frequency variable control by the control means, the control means receives a voltage signal proportional to the amount of reflected power detected by the means for detecting the reflected power, compares the input voltage signal with two reference levels, When the reflected power exceeds the first predetermined amount, the driving voltage of the amplifying unit connected to the target radiating means is reduced, and when the second predetermined amount larger than the first predetermined amount is exceeded, the target radiating means is The drive power supply of the connected amplifying unit is stopped , the frequency variable control is continued even after the drive power supply control of the amplifying unit, and according to the amount of reflected power detected after the variable control,
A microwave utilization device that controls heating power to heat an object to be heated. 3. A structure comprising a plurality of frequency variable function microwave generating means, and a plurality of control means for variably controlling the oscillation frequency generated by each of the microwave generating means in predetermined time intervals and steps. The microwave utilization apparatus as described in. The control means captures a signal indicating whether power is supplied to each amplification unit, and when all the amplification units are operating, slows the frequency variable speed, and stops all the amplification units from operating. The microwave utilization apparatus according to any one of claims 1 to 3, wherein the frequency variable speed is increased when the frequency is changed. The microwave utilization apparatus according to any one of claims 1 to 3, wherein the plurality of radiating means are configured to radiate microwaves in a direction of a placing means for placing an object to be heated. The microwave utilization apparatus according to any one of claims 1 to 3, wherein the plurality of radiation means have different resonance frequencies. 4. The microwave utilization device according to claim 3, wherein the plurality of microwave generation means are configured not to overlap the oscillation frequencies of the respective oscillation units.

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