JP5169255B2 - Microwave processing equipment - Google Patents

Description

  The present invention relates to a microwave processing apparatus including a microwave generation unit configured using a semiconductor element.

  Conventionally, this type of microwave processing apparatus has a conventional technique in which a heating chamber is formed of six or more polyhedrons, and a radiating antenna is disposed so as to protrude from a part or all of each surface into the heating chamber (for example, Patent Document 1). Mutual interference can be prevented by arranging the radiating antennas on different surfaces, and since the radiating antennas are directed in different directions, the radiated radio waves propagate in all directions in the heating chamber and are reflected and scattered by the wall surface. Therefore, the radio waves are uniformly distributed in the heating chamber.

  A semiconductor oscillation unit; a distribution unit that divides the output of the oscillation unit into a plurality of units; a plurality of amplification units that amplify the distributed outputs; and a synthesis unit that synthesizes the outputs of the amplification units. There is a conventional technique in which a phase shifter is provided between the two (see, for example, Patent Document 2). The power ratio of the two outputs can be changed by the phase shifter control, or the phase between the two outputs can be in phase or in phase.

There is a conventional technique for detecting the reflected power returning from the heating chamber in which the object to be heated is returned to the microwave generation unit and tracking the oscillation frequency at which the reflected power is minimized based on the reflected power signal (for example, And Patent Document 3).
JP-A-52-19342 JP 56-132793 A JP-A-56-96486

  However, in the configuration of the conventional multiple power feeding method, as described below, it is difficult to heat-treat objects to be heated in various shapes, types, and quantities stored in a heating chamber to a desired state. Had.

  With regard to the arrangement of the radiating antennas, the space that can be used is limited due to the demand for expansion of the heating chamber capacity occupying the equipment volume, and it is practically difficult to install them on six surfaces. In addition, mutual interference cannot be reliably prevented only by disposing them on different surfaces.

  Since phase control works between microwaves that interfere with each other, it cannot be used in combination with multi-sided antenna arrangement or different frequency operation, and an effect under a wide range of conditions cannot be expected.

  The present invention solves the above-described conventional problems, and optimally controls the control of the excitation frequency of the microwave radiated from the power supply unit, the operation frequency and phase, and the power amplification amount associated with the control of the excitation direction. It aims at providing the microwave generation processing apparatus which heat-processes the to-be-heated object from which various shapes, a kind, and quantity differ in desired state.

In order to solve the above-described conventional problems, a microwave processing apparatus according to the present invention includes a heating chamber that accommodates an object to be heated, an oscillation unit that generates microwaves, and an output of the oscillation unit that is divided into a plurality of outputs. A power distribution unit, a plurality of phase variable units that vary the output phase of each of the power distribution units, an amplification unit that amplifies the power of each of the outputs of the power distribution unit or the phase variable unit, and A plurality of power supply units for supplying an output to the heating chamber; a means for setting an excitation direction of microwaves radiated from the power supply unit to at least one of the plurality of power supply units; A microwave processing apparatus having a means for variably controlling the phase between the units, wherein an operating frequency for the combination of the power feeding units in which the excitation direction of the microwave radiated from the power feeding unit is set to an arbitrary direction And phase and Microwave processing means with control of the amount of force amplification and detection means for detecting transmitted and reflected power amounts, and in the execution of the microwave processing means and the detection means, from a plurality of combinations with respect to the excitation direction of the power feeding unit Determine the best one and
It is set as the structure which resets the excitation direction of an electric power feeding part and performs heat processing, changing the combination to select . The present invention combines the control of the excitation direction of the microwave radiated from the power supply unit with the control of the operating frequency, phase, and power amplification amount associated with the control of the excitation direction, and has various shapes, types, and quantities. Different objects to be heated can be heat-treated in a desired state.

  The microwave processing apparatus of the present invention performs various combinations of the control of the excitation direction of the microwave radiated from the power feeding unit and the control of the operating frequency and phase and the amount of power amplification performed in association with the control of the excitation direction. It is possible to provide a microwave processing apparatus that heat-treats different types and amounts of objects to be heated to a desired state.

The first invention includes a heating chamber that houses an object to be heated, an oscillator for generating a microwave, a power distribution unit for outputting the distributed output of the oscillation part to a plurality, between the output of the power distribution unit a phase variable unit for varying the phase of the power distribution unit or the amplifier for power-amplifying the output of the phase variable parts, and a plurality of feeding parts supplying outputs to said heating chamber of said amplifying unit, said plurality Means for setting the direction of the electric field or magnetic field of the microwave radiated from the power supply unit to at least one of the power supply units (hereinafter referred to as the excitation direction), and the phase between the plurality of power supply units is variable. A microwave processing apparatus having a control means, wherein an operating frequency, a phase, and a power amplification amount for a combination of the power feeding units in which an excitation direction of microwaves radiated from the power feeding unit is set to an arbitrary direction Microphone with control A wave processing means, and a detection means for detecting the amount of transmitted and reflected power, and in the execution of the microwave processing means and the detection means, determine an optimum one from a plurality of combinations with respect to the excitation direction of the power feeding unit, In this configuration, the heat treatment is performed while resetting the excitation direction of the power feeding unit and switching the combination to be selected. This makes it possible to select the heat treatment in the excitation direction, operating frequency, phase, and output suitable for the object to be heated stored in the heating chamber, and to suit each object to be heated in various shapes, types, and quantities. Can be heated to the desired state. In addition, by controlling the excitation direction of the radiating microwave, it is possible to intentionally select a combination of feeding units that cause mutual interference and a combination of feeding units that do not cause mutual interference.

Furthermore, it is possible to use a combination of power supply units in the optimum excitation direction for each of the microwave processing means and the detection means, and it is possible to heat the object to be heated in various shapes, types, and quantities to a desired state. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a configuration diagram of a microwave processing apparatus according to the first embodiment of the present invention.

  In FIG. 1, the microwave generation unit includes oscillation units 1 a and 1 c configured using semiconductor elements, power distribution units 2 a and 2 c that distribute the outputs of the oscillation units 1 a and 1 c, and outputs of the power distribution units 2 a and 2 c. The phase variable units 3a to 3d that generate an arbitrary phase shift from the amplifiers, the amplifiers 4a to 4d that amplify the outputs of the phase variable units 3a to 3d, and the microwave output amplified by the amplifiers 4a to 4d are radiated into the heating chamber. Power detectors 5a to 5d, power detectors 6a to 6d that detect power reflected from the power feeders 5a to 5d inserted in the microwave transmission path connecting the amplifiers 4a to 4d and the power feeders 5a to 5d, and a power detector Control for controlling the oscillation frequencies of the oscillation units 1a and 1c, the phase adjustment amounts of the phase variable units 3a to 3d, and the amplification amounts of the amplification units 4a to 4d in accordance with the reflected power detected by 6a to 6d It is composed of a 7.

  The power distribution units 2a and 2c may be, for example, Wilkinson distributors, or may be distributors that generate a phase difference between outputs, such as a branch line type or a rat race type. The power distribution units 2a and 2c transmit substantially half of the microwave power input from the oscillation units 1a and 1c to the respective outputs. The phase variable units 3a to 3d are configured using a variable capacitance element whose capacitance changes according to the applied voltage, and the phase difference of the output microwave power can be controlled in the range of 0 to ± 180 degrees. it can.

  The amplifying units 4a to 4d are configured by a conductor pattern formed on one side of a dielectric substrate made of a low dielectric loss material, and a matching circuit that operates the semiconductor element that is an amplifying element of each amplifying unit satisfactorily. Arranged. The microwave transmission path connecting each functional block is formed by a conductor pattern transmission circuit provided on one surface of a dielectric substrate, a coaxial cable, or the like. The power detectors 6a to 6d extract the power of so-called reflected waves that are transmitted from the heating chamber 8 side to the microwave generator side, respectively. The power coupling degree is, for example, about 40 dB, and the reflected power is about 1/10000. The amount of power is extracted. The power signals are rectified by a detection diode (not shown), smoothed by a capacitor (not shown), and the output signal is input to the control unit 7.

  The control unit 7 generates microwave excitation electric fields 11a and 11d radiated from the power supply units 5a and 5d based on the heat treatment condition of the object to be heated that is directly input by the user and the detection information from the power detection units 6a to 6d. And the driving power supplied to each of the oscillating units 1a, 1c and the amplifying units 4a to 4d and the voltage supplied to the phase variable units 3a to 3d are controlled in association with the control of the excitation direction. The stored object to be heated is optimally heat-treated.

  In the above description, the example in which two phase variable units are inserted has been described. However, the phase change width is set to 0 degree to 360 degrees by inserting only one of the outputs of the power distribution unit 3a. You can also

  In addition, the microwave processing apparatus of the present invention has a heating chamber 8 having a substantially rectangular parallelepiped structure that accommodates an object to be heated, and the heating chamber 8 has a left wall surface, a right wall surface, a bottom wall surface, an upper wall surface, and a back wall made of a metal material. An open / close door (not shown) that opens and closes to store the wall surface and the object to be heated, and a mounting table on which the object to be heated is placed, are configured to confine the supplied microwave inside. . And the electric power feeding parts 5a-5d which radiate | emit a microwave in the heating chamber 8 are arrange | positioned at the left, right, upper, and bottom wall surface which comprise the heating chamber 8. FIG. The arrangement of the power feeding units is not limited to the present embodiment, and a plurality of power feeding units may be provided on any wall surface.

  The power feeding units 5a and 5d are rotated by rotation control units 9a and 9d including means for detecting a rotation position (not shown) and means for controlling a rotation angle (not shown), and the excitation direction is adjusted. can do.

  In the above description, the rotation control units 9a and 9d, the means for detecting the rotation position, and the means for controlling the rotation angle correspond to the excitation direction setting means described in the claims.

  The operation of the microwave processing apparatus configured as described above will be described below.

First, the object to be heated 10 is stored in the heating chamber 8, the heat treatment conditions are input from an operation unit (not shown), and the heating start key is pressed. Upon receiving the heating start signal, the control unit 7 sends a control output signal to the oscillating units 1a and 1c formed of a semiconductor element whose operating frequency can be controlled, and starts oscillating at a frequency suitable for the selected heat treatment condition. When the oscillating units 1a and 1c are operated, their outputs are distributed approximately ½ each by the power distributing units 2a and 2c to become four microwaves. The phase of each microwave is shifted by the specified amount from the control unit 7 by the phase variable units 3a to 3d, and the specified amount is amplified from the control unit 7 by the amplifying units 4a to 4d operating individually in parallel. Then, the electric power is supplied to the power feeding units 5 a to 5 d via the power detection units 6 a to 6 d, and the excitation electric fields 11 a to 11 d are generated by the power feeding units 5 a to 5 d to radiate microwaves into the heating chamber 8.

  The power detection units 6a to 6d detect the reflected power returning to the microwave generation unit and detect a signal proportional to the amount of reflected power. The control unit 7 that has received the detection signal is selected. Select and execute the optimal operating conditions according to the menu and the embedded program.

  The present invention controls the excitation direction of microwaves to be radiated, and controls the operating frequency and phase performed in association with the excitation direction control in combination with the amount of power amplification, and is heated in various shapes, types, and quantities. Although there is an effect of heat-treating an object to a desired state, in order to heat-treat the object to a desired state, mainly “highly efficient heating performance” and “heating performance with little unevenness” are required. The two performances will be described below.

  When the microwave power generated in the oscillators 1a and 1c is efficiently radiated into the heating chamber 8 and absorbed 100% by the object to be heated, the reflected power from the heating chamber 8 side becomes 0 W. Reflection due to mismatch between the impedance of the heating chamber 8 including the heated object determined by the type, shape, and quantity of the heated object and the output impedance of the power feeding units 5a to 5d coupled to the heating chamber 8, and absorption by the heated object 10 Instead, the microwave power picked up by the power feeding units 5a to 5d returns to the generation unit side as reflected power. In the following, the operation of suppressing the reflected power to obtain a highly efficient heating performance will be described.

  In the heating chamber 8, microwaves are radiated from the plurality of power feeding units 5 a to 5 d, and microwaves in various excitation directions, electric powers, and propagation directions are disturbed, but in individual fields in the heating chamber 8, An electromagnetic field distribution in the heating chamber is formed by mutual interference that overlaps if the same electric field direction overlaps and cancels if the same electric field direction is opposite. The strength of the electric field in each field is related to the operating frequency, radiation power, and phase shift at the radiation location. In addition, the electric field direction of each field is deeply related to the excitation direction in the power feeding units 5a to 5d, and the combination and the degree of microwaves that interfere with each other are also determined by this electric field direction. However, if the combination of microwaves having the same operating frequency is not used, the mutual interference state fluctuates even if the excitation directions are the same, and the phase control is not effective.

  By adjusting the direction of the excitation electric field 11a of the power supply unit 5a with the rotation control unit 9a and adjusting the operating frequency, phase, and power amplification amount for the combination with the power supply unit 5b having substantially the same excitation electric field, The electromagnetic field distribution can be changed directly. The microwave generation sources of the power feeding units 5 a and 5 b are the same oscillation unit 1 a, and the operating frequency can be adjusted to match with the signal from the control unit 7. The phase can be controlled by associating the phase variable units 3a and 3b with a signal from the control unit 7 and set to a necessary phase difference. The amount of power amplification can arbitrarily control the amplifying units 4 a and 4 b by a signal from the control unit 7. In this way, it is possible to increase the microwave absorption efficiency by adjusting the conditions of the microwaves to be interfered and intentionally manipulating the electromagnetic field distribution to concentrate the electromagnetic field distribution on the object to be heated 10.

  Furthermore, by adjusting the direction of the excitation electric field 11d of the power supply unit 5d by the rotation control unit 9d and combining it with the excitation electric field 11c of the power supply unit 5c, another combination with mutual interference can be formed. Since the feeding units 5c and 5d have different excitation directions from the combination of the feeding units 5a and 5b, the mutual interference relationship is not disturbed. If the electromagnetic field distribution formed by the power feeding units 5c and 5d is supplemented with the electromagnetic field distribution by the power feeding units 5a and 5b, the microwave absorption efficiency of the object to be heated 10 can be further increased. It becomes.

In addition, the antenna has characteristics of a direction in which radio waves are easily radiated and received (directivity) and an electric / magnetic field direction (excitation direction). Once these characteristics are met, the antenna is once radiated into the heating chamber 8 to be heated. It becomes easy to pick up the microwave electric power which is not absorbed by 10. This phenomenon works in the same way for microwaves radiated from other power supply units. In the case of FIG. 1, the excitation directions of the excitation electric fields 11a and 11b coincide with each other, and there is mutual radiation between combinations having mutual interference. It is easy to receive radio waves. When the electromagnetic field distribution is not controlled by mutual interference, the rotation control unit 9a changes the direction of the excitation electric field 11a of the power supply unit 5a, thereby reducing the amount of microwave power received by matching the excitation directions, and high efficiency. Contributes to the heating performance.

  As described above, the microwave excitation electric fields 11a to 11a to be radiated from the power feeding units 5a to 5d are also applied to the objects to be heated having various shapes, sizes, and quantities based on the reflected power detected by the power detection units 6a to 6d. By controlling the operating direction and phase determined in association with the excitation direction of 11d and the control of the excitation direction and the radiated power, it is possible to find a condition where the reflected power is minimized, and to perform the heat treatment. Performance ".

  The microwaves radiated to the heating chamber 8 in the limited closed space are absorbed by the object to be heated 10, picked up by the power feeding units 5 a to 5 d, or repeatedly reflected on the wall surface of the heating chamber 8. Although the field distribution is formed, the electromagnetic field distribution causes the intensity of heating in each field. The effect | action which suppresses heating nonuniformity is demonstrated below.

  The inside of the heating chamber 8 is controlled by the excitation frequency 11a to 11d of the microwaves radiated from the power feeding units 5a to 5d, the operation frequency and phase performed in association with the control of the excitation direction of the excitation fields 11a to 11d, and the power amplification amount control. The electromagnetic field distribution can be manipulated and can be adjusted more uniformly. Further, the group of the power feeding units 5a and 5b and the group of the power feeding units 5c and 5d having different excitation directions are operated at the same time in the electromagnetic field distribution formed by the power feeding units 5c and 5d. If the electromagnetic field distribution due to is complemented, a more uniform heating pattern can be formed.

  In actual cooking, a uniform electromagnetic field distribution does not always give an optimal result, and when the object to be heated is large, the surroundings are more likely to accumulate heat than the center where heat diffusion is good, resulting in uneven temperature. Similarly, thawing tends to facilitate the surrounding heating. For this reason, according to the cooking conditions of the selected object to be heated, the centralized electromagnetic field distribution is intentionally controlled by controlling the excitation direction, the operation frequency and phase performed in association with the control of the excitation direction, and the amount of power amplification. As a result, a good finish can be obtained by cooking under the condition of strengthening.

  Even if the electromagnetic field distribution unevenness is small, if the same pattern heating is continued, uneven heating due to heat storage in the same place occurs. Furthermore, since the object to be heated itself is not homogeneous, a deviation in the amount of heat generation also occurs. Therefore, the operating frequency, phase, and power amplification amount are intentionally changed during cooking, or the rotation control units 9a and 9d change the directions of the excitation electric fields 11a and 11d of the power supply units 5a and 5d, By switching the combination, the electromagnetic field distribution can be changed and the uneven heating can be reduced.

  In this way, the control of the excitation direction of the microwave excitation electric fields 11a to 11d radiated from the power supply units 5a to 5d, the operation frequency and phase performed in association with the control of the excitation direction, and the power amplification amount are controlled, By controlling the optimal electromagnetic field distribution as intended, it is possible to heat the object to be heated in various shapes, sizes, and quantities under conditions that minimize the uneven heating. Can be obtained.

  Depending on the object to be heated in various shapes, sizes, and quantities, the combination of the power feeding unit according to the microwave excitation direction, the operating frequency and phase, the optimum heating condition of the radiated power, and the power feeding unit according to the microwave excitation direction Optimal detection conditions for the combination vary. For example, when the optimum combination of power supply units for heat treatment is 5a and 5d and the optimum combination of detection power supply units for detection is 5a and 5b, the optimum heating condition and the optimum detection condition cannot be compatible at the same time. By re-installing 5a with the rotation control unit 9a, switching between detection and microwave processing and proceeding while maintaining optimum conditions, a more optimal result can be obtained.

  In addition, physical properties such as microwave absorption characteristics of an object to be heated may change due to a temperature rise, and the optimum heating conditions and optimum detection conditions also vary. Based on the fluctuations in the reflected power detected by the power detection units 6a to 6d, by adjusting the combination of the power feeding units according to the excitation direction of the microwave and the optimum conditions of the operating frequency and phase and the radiated power, Heat treatment that satisfies "highly efficient heating performance" and "uneven heating performance" can be performed.

  The power detection units 6a to 6d are provided in all the power supply units 5a to 5d, and detect microwave power picked up (received) in accordance with the characteristics of the antenna directivity and excitation direction in each installation part. There is a limit to detection at the power feeding unit. For example, in the power feeding unit 5a, the electric fields in the width direction and the depth direction of the heating chamber 8 can be picked up (can be received), but cannot be picked up (cannot be received) in the vertical direction. Further, only the electromagnetic field distribution near the upper wall surface of the heating chamber 8 is detected. Therefore, the detection accuracy is improved by estimating the condition of the heated object 10 installed in the heating chamber 8 in cooperation with the detection from all the power supply units 5a to 5d.

  As described above, the microwave processing apparatus according to the present invention has a plurality of power feeding units, and controls the direction (excitation direction), operating frequency, phase difference, and power of the microwave electric field / magnetic field radiated from the power feeding unit. Since the apparatus to be changed can be provided, it can be applied to applications such as a heat treatment apparatus using a dielectric heating as typified by a microwave oven, a garbage processing machine, or a microwave power source of a plasma power source as a semiconductor manufacturing apparatus.

Configuration diagram of microwave processing apparatus according to Embodiment 1 of the present invention

DESCRIPTION OF SYMBOLS 1a, 1c Oscillator 2a, 2c Power distribution part 3a-3d Phase variable part 4a-4d Amplification part 5a-5d Power supply part 6a-6d Power detection part 7 Control part 8 Heating chamber 9a, 9d Rotation control part 10 Heated object 11a ~ 11d Excitation electric field

Claims (1)

A heating chamber for storing an object to be heated;
An oscillation unit for generating microwaves;
A power distribution unit that distributes and outputs the output of the oscillation unit to a plurality of outputs;
A phase variable unit that varies a phase between outputs of the power distribution unit;
An amplifying unit for amplifying the output of the power distributing unit or the phase variable unit;
A plurality of power supply units that supply the output of the amplification unit to the heating chamber ;
Means for setting an excitation direction of microwaves radiated from the power feeding unit to at least one of the plurality of power feeding units in an arbitrary direction;
A microwave processing apparatus having a means for variably controlling the phase between the plurality of power feeding units , wherein the microwave excitation direction radiated from the power feeding unit is set to an arbitrary direction with respect to the combination of the power feeding units. Microwave processing means with control of operating frequency, phase and amount of power amplification,
A detecting means for detecting the amount of transmitted and reflected power;
In the execution of the microwave processing means and the detection means, the optimum one is determined from a plurality of combinations with respect to the excitation direction of the power feeding unit, the excitation direction of the power feeding unit is reset, and heating is performed while switching the combination to be selected. A microwave processing apparatus configured to perform processing.

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