JP2010198752A - Microwave processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device which heats various heating objects highly efficiently by operating microwave distribution by control of the direction of excitation electric field of the power supply part arranged in the wall of a heating chamber. <P>SOLUTION: The microwave heating device is provided with oscillation portions 1a, 1c, power distribution portions 2a, 2c, amplification portions 4a-4d, a heating chamber 8 which contains a heating object 9, power supply portions 5a-5d which are arranged in the bottom wall of the heating chamber 8 and radiate microwave, and phase variable portions 3a-3d inserted in the microwave propagation passage. The device controls optimally the direction of excitation electric field, phase difference, and oscillation frequency of the microwave emitted from the power supply portions 5a-5d, and thereby, reflection power is controlled to a minimum to various heating objects and highly efficient heating can be attained. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

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

  A conventional microwave processing apparatus of this type is generally composed of a rectangular parallelepiped heating chamber and includes one or a plurality of power feeding units. As a structure of a some electric power feeding part, there exists a thing which provided the electric power feeding part in the upper wall surface and bottom wall surface of a heating chamber, and supplied the microwave to each electric power feeding part from the microwave generation part for exclusive use.

  In addition, with the aim of promoting uniform heating of the object to be heated, the heating chamber is formed in a polyhedron having six or more faces, and a radiation antenna as a power feeding portion protrudes from a part or all of each wall surface into the heating chamber. (See, for example, Patent Document 1). And it is supposed that mutual interference can be prevented by arranging the mutual radiation antennas on different surfaces. Furthermore, 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, so that the radio waves are uniformly distributed in the heating chamber.

  In addition, there is an antenna in which at least two of the antennas connected to the solid-state oscillator are arranged on the same wall surface of the heating chamber (for example, see Patent Document 2). By increasing the number of installed antennas, uneven heating can be reduced, uniform heating can be achieved, and the influence of reflected waves can be eliminated due to the orientation relationship between the antennas.

  Also provided with a phase shifter, a semiconductor oscillating unit, a distributing unit that divides the output of the oscillating unit into a plurality of components, a plurality of amplifying units that amplify the distributed outputs, and a combining unit that combines the outputs of the amplifying units And a phase shifter is provided between the distribution unit and the amplification unit (see, for example, Patent Document 3). The phase shifter is configured to switch the microwave pass line length according to the on / off characteristics of the diode. Moreover, the synthesis unit can use two 90-degree and 180-degree hybrids, so that the output of the synthesis unit can be made two. By controlling the phase shifter, the power ratio of the two outputs can be changed, or the phase between the two outputs Can be in phase or out of phase.

In addition, this type of microwave processing apparatus generally uses a vacuum tube called a magnetron in a microwave generation section as represented by a microwave oven.
JP-A-52-19342 Japanese Utility Model Publication No. 52-16654 JP 56-132793 A

  However, the conventional multiple power feeding units are arranged so as to avoid interference between the power feeding units, and the microwaves radiated from the respective power feeding units have different radiation directions. It is impossible to prevent interference from microwaves radiated from other radiating antennas because scattering due to reflection on the wall surface and the scattered microwave hits the wall surface and becomes a wide range of scattering due to repeated scattering. It is.

  Also, in the case where a plurality of antennas are arranged on the same wall in the heating chamber, the difference from the simple provision of multiple antennas is not clear, and there is no disclosure of the content of the effect of providing the same wall. It is only possible.

  Further, in the case of a device equipped with a phase shifter, the microwaves radiated from the two outputs of the combining unit can change the radiated power ratio and phase difference from the two radiating antennas by changing the phase by the phase shifter. Although it is possible to change it instantaneously, it is difficult to heat objects to be heated in various shapes, types, and quantities stored in a heating chamber to which microwaves are supplied by radiation to a desired state. Was.

  The present invention solves the above-described conventional problems, and optimally interferes microwaves radiated from each of a plurality of power feeding units, thereby allowing various shapes, types, and amounts of objects to be heated to be in a desired state. An object of the present invention is to provide a microwave processing apparatus that heats the heat.

  In order to solve the above-described conventional problems, the microwave processing apparatus of the present invention can rotate the direction of the electric field or magnetic field of the microwave radiated from the power supply unit provided on the wall surface constituting the heating chamber. Provided an apparatus that efficiently heats an object to be heated that is housed in a heating chamber, with a configuration in which heat treatment is performed under the condition of the electric field or magnetic field that minimizes the microwave power reflected in the direction of the amplifier and the frequency condition. it can.

  The microwave processing apparatus of the present invention radiates microwaves from the power supply unit into the heating chamber under the electric field or magnetic field orientation conditions and frequency conditions that minimize the microwave power reflected from the power supply unit in the direction of the amplification unit. It is possible to provide a microwave processing apparatus that efficiently heats objects to be heated having various shapes, types, and amounts.

  A first invention includes a heating chamber that accommodates an object to be heated, an oscillation unit, a power distribution unit that distributes and outputs the output of the oscillation unit, and a phase that varies at least one output phase of the power distribution unit The variable section, the power distribution section and / or the amplification section that amplifies the output of the phase variable section, the radiation section that radiates microwave power to the heating chamber, and the propagation section that transmits the output of the amplification section to the radiation section A power supply unit, a power detection unit that detects microwave power reflected from each power supply unit in the direction of the amplification unit, and a control unit that controls the oscillation frequency of the oscillation unit and the phase amount of the phase variable unit. The propagating part is made into an axial shape, the radiating part can be rotated about the propagating part as a central axis, and the direction of the electric field or magnetic field of the microwave radiated from the radiating part is changed by the rotating action of the radiating part. Radiate from the power supply Can control the electric or magnetic field orientation in the microwave, it is possible to heat various shapes, types and quantity of different object to be heated efficiently.

  In the second aspect of the invention, in particular, the propagation part of the power feeding part of the first aspect of the invention penetrates the shaft connected to the radiating part and the hole provided in one wall surface constituting the heating chamber in a non-contact manner and directly into the amplification part. Alternatively, the two axes of the indirectly connected shafts are partially combined in a coaxial shape, and the radiating section can be rotated about the propagation section as a central axis, and the electric field or magnetic field of the microwave radiated from the power feeding section The direction can be controlled, and heated objects with various shapes, types, and quantities can be efficiently heated.

  In the third aspect of the invention, in particular, the two outer shafts combined in the coaxial shape constituting the propagation part of the first or second aspect of the invention are such that the high-frequency current of the propagating microwave is 1 / e (about 0. 37) A tube-shaped configuration having a thickness equal to or larger than that of the thickness 37) can suppress the microwave power loss in the propagation part, and can efficiently heat objects to be heated having various shapes, types, and amounts.

In particular, the fourth aspect of the invention is a structure in which the inner shaft is rotatably held inside the two outer tube-shaped shafts combined in the coaxial shape constituting the propagation part of the first or second invention, It is possible to efficiently heat objects to be heated of various shapes, types, and amounts while suppressing loss in the outer portion of the propagation portion through which most of the microwave power propagates.

  In particular, the fifth aspect of the present invention has a configuration in which the inner shaft is held so as not to come out of the two outer tube-shaped shafts combined in the coaxial shape constituting the propagation portion of the first or second invention. In addition, the rotation of the radiating unit can be stabilized, the control of the direction of the electric field or magnetic field of the microwave radiated from the power feeding unit can be maintained, and the objects to be heated of various shapes, types, and quantities can be efficiently heated.

  In the sixth aspect of the invention, in particular, the two outer tube-shaped shafts combined in the coaxial shape constituting the propagation part of the first, second, or fourth aspect of the invention and the inner shaft are in contact with each other except the portion held rotatably. In this configuration, it is possible to efficiently heat objects to be heated having various shapes, types, and amounts while suppressing the microwave power loss in the propagation part.

  In the seventh aspect of the invention, in particular, the end portions of the two outer tube-shaped shafts combined in the coaxial shape constituting the propagation portion of the first or second aspect of the invention are configured in a tapered shape. It is possible to efficiently heat objects to be heated of various shapes, types, and quantities while suppressing reflection of microwave power.

  In the eighth aspect of the invention, in particular, the radiating portion of the first or second aspect of the invention is provided between the radiating portion and one wall surface constituting the heating chamber, and a dielectric that interlocks with the shaft connected to the radiating portion or the radiating portion is provided. It is configured to be driven, can perform stable rotation control regardless of the shape of the radiating portion, and can efficiently heat objects to be heated having various shapes, types, and amounts.

  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. Amplifying units 4a to 4d configured using semiconductor elements to be amplified, power feeding units 5a to 5d for radiating the microwave output amplified by the amplifying units 4a to 4d into the heating chamber 8, and power distribution units 2a and 2c and amplification Phase variable units 3a to 3d that are inserted into the microwave propagation path connecting the units 4a to 4d and generate an arbitrary phase difference between input and output, and the microwave propagation path that connects the amplifiers 4a to 4d and the power feeding units 5a to 5d Detected by the power detection units 6a to 6d and the power detection units 6a to 6d that detect the microwave power (hereinafter referred to as reflected power) that is inserted and reflected in the direction of the amplification units 4a to 4d from the power supply units 5a to 5d. Depending on the reflected power is composed of a control unit 7 for controlling the phase of the oscillation frequency and the phase variable parts 3a~3d of the oscillator 1a, 1c.

  Further, the microwave processing apparatus of the present invention has a heating chamber 8 that accommodates an object 9 to be heated and has a substantially rectangular parallelepiped structure, and the heating chamber 8 is opened and closed to accommodate a wall surface made of a metal material and the object 9 to be heated. The microwave to be supplied is confined in the opening / closing door (not shown) and the mounting table 10 on which the object to be heated 9 is mounted. Then, the microwave outputs generated by the oscillation units 1 a and 1 c are propagated, and the four power supply units 5 a to 5 d that radiate the heat into the heating chamber 8 are all disposed on the bottom wall surface that constitutes the heating chamber 8. The four power supply units 5a to 5d can operate the rotation operation units 12a to 12d to rotate the antenna direction under the control of the control unit 7, and control the directions of the excitation fields 11a and 11c of the radiated microwaves. it can.

The amplifying units 4a to 4d constitute a circuit with a conductor pattern formed on one side of a dielectric substrate made of a low dielectric loss material, and each semiconductor is operated in order to operate a semiconductor element that is an amplifying element of each amplifying unit satisfactorily. Matching circuits are arranged on the input side and output side of the element, respectively. The power distribution units 2a and 2c may be in-phase distributors that do not cause a phase difference between outputs such as a Wilkinson distributor, or may have a phase difference between outputs such as a branch line type or a rat race type. It may be the resulting distributor. The power distribution units 2a and 2c propagate approximately 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 each phase variable range is a range from 0 degrees to about 180 degrees. As a result, the phase difference of the microwave power output from the phase variable units 3a to 3d can be controlled in the range of 0 degree to ± 180 degrees. The power detection units 6a to 6d extract microwave so-called reflected power reflected from the power feeding units 5a to 5d in the direction of the amplification units 4a to 4d. The power coupling degree is, for example, about 40 dB, and about 1 / of the reflected power. Extract 10,000 electric energy. 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 includes the oscillation units 1a and 1c and the amplification units 4a to 4a that are components of the microwave generation unit based on the heating conditions of the object to be heated and the detection information of the power detection units 6a to 6d that are directly input by the user. Control of driving power supplied to each of 4d, control of voltage supplied to the phase variable units 3a to 3d and operation of the rotating operation units 12a to 12d to control the directions of the excitation fields 11a and 11c of the radiated microwaves, The object to be heated 9 accommodated in the heating chamber 8 is optimally heated.

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

  First, the object to be heated 9 is stored in the heating chamber 8, the heating condition is input from an operation unit (not shown), and the heating start key is pressed. In response to the control output signal of the control unit 7 that has received the heating start signal, the microwave generation unit starts operation. The control means 7 operates a drive power supply (not shown) to supply power to the oscillation units 1a and 1c. At this time, the initial oscillation frequency of the oscillation units 1a and 1c is supplied with a voltage signal set to 2400 MHz, for example, and oscillation starts. When the oscillating units 1a and 1c are operated, their outputs are distributed approximately ½ each by the power distributing units 2a and 2c, resulting in four microwave power signals. Thereafter, the drive power supply is controlled to operate the amplification units 4a to 4d. The microwave power signals are output to the power feeding units 5a to 5d through the amplification units 4a to 4d and the power detection units 6a to 6d that operate in parallel, and are radiated into the heating chamber 8, respectively.

  When 100% of the microwave power supplied into the heating chamber 8 is absorbed by the object 9 to be heated, the reflected power from the heating chamber 8 becomes 0 W. Depending on the type, shape, and amount of the object to be heated, The impedance changes, and microwave power propagating from the power supply units 5a to 5d in the direction of the amplification units 4a to 4d is generated due to misalignment with the microwave power supply side. The power detectors 6 a to 6 d detect the microwave power and send a detection signal proportional to the amount of reflected power to the control unit 7.

The control unit 7 controls the rotational operation units 12a to 12d and performs microwave excitation electric fields 11a radiated from the power supply units 5a to 5d in a stage before heat-treating the object 9 accommodated in the heating chamber 8. 11c are matched, and the oscillation units 1a and 1c and the phase variable units 3a to 3d are controlled to determine the oscillation frequency that minimizes the total value of the reflected power detected by the power detectors 6a to 6d. Preliminary detection operation for confirming is performed. In the preliminary detection operation, the control unit 7 operates the oscillation frequencies of the oscillation units 1a and 1c, for example, from 2400 MHz until reaching the upper limit of the variable frequency range of 2500 MHz from 1400 MHz, and at the same time from the power supply units 5a to 5d to the amplification units 4a to 4a. By detecting the microwave power reflected in the 4d direction by the power detectors 6a to 6d, a frequency condition that minimizes the reflected power can be obtained. Similarly, the relative phase difference between the power feeding units is changed to the phase variable unit 3.
It is possible to determine the phase control condition that is adjusted by the control of a to 3d and minimizes the total value of the reflected power detected by the power detectors 6a to 6d.

  The control unit 7 controls the oscillation units 1a and 1c and the phase variable units 3a to 3d under the conditions of the oscillation frequency and the phase difference at which the reflected power is minimized so that an output corresponding to the input heating condition can be obtained. To control the oscillation output. The microwaves of the oscillation frequency according to the control of the control unit 7 become power according to the control in the amplification units 4a to 4d, supplied to the respective power feeding units 5a to 5d with a phase difference corresponding to the control, and Radiated into the heating chamber 8. Based on the frequency condition and the phase control condition for minimizing the reflected power obtained in the preliminary detection operation in this way, heating is started in accordance with the characteristics in the heating chamber 8 including the object to be heated. The microwave 9 radiated to the object 9 can be efficiently absorbed by the object 9 to be heated, and the object 9 having various shapes, types and amounts can be absorbed under the expected operating conditions where the reflected power is minimized. Efficient heating can be continued, and it is possible to prevent the semiconductor elements provided in the amplifying units 4a to 4d from excessively generating heat due to the reflected power, and to avoid thermal destruction.

  In this embodiment, the configuration of power supply at four points is shown, but the present embodiment is not limited to this embodiment, and various shapes and types are similarly controlled by controlling the respective excitation directions when the number of power supply units is increased. -Highly efficient heating can be performed under the setting conditions as expected even when the quantity of heated objects is different.

  FIG. 2 is a cross-sectional view of the power feeding unit according to the first embodiment of the present invention.

  In FIG. 2, the power feeding unit rotates the radiation unit 13 that radiates microwave power into the heating chamber 8, the propagation unit 14 that propagates microwaves, the relay unit 17 that relays the propagation unit 14 and the amplification unit, and the radiation unit 13. The drive unit 16 is operated. The propagation unit 14 includes a propagation unit outer shaft 141 joined to the radiation unit 13 and a propagation unit inner shaft 142 that transmits the microwave from the relay unit 17. The propagation unit outer shaft 141 and the propagation unit inner shaft 142 are composed of the propagation unit. The outer tube portion 143 has a coaxial structure. The propagation portion outer shaft tube-shaped portion 143 has a thickness where the high frequency current is 1 / e of the surface current (e is the base of natural logarithm), that is, about 0.37 times the thickness, and the propagation portion omission prevention 144 provided inside Only the propagation part bearing 145 is in contact with the propagation part inner shaft 142 and is held in a rotatable state by bearings while preventing slippage. The lower end portion of the propagation portion outer shaft 141 is tapered to eliminate a sudden impedance change and reduce reflection on the microwave propagation path. The radiating portion 13 is joined to the cylindrical dielectric 15 and receives a rotational driving force from the driving portion 16 in contact with the outer peripheral portion of the dielectric 15 to rotate.

  As described above, the microwave processing apparatus according to the present invention can rotate the direction of the electric field or magnetic field of the microwave radiated from the power supply unit provided on the wall surface constituting the heating chamber, and is directed from the power supply unit to the amplification unit. Since heat treatment can be performed under the electric field or magnetic field orientation conditions and frequency conditions that minimize the reflected microwave power, a heating device or a garbage disposal machine that uses dielectric heating, such as a microwave oven, or The present invention can also be applied to applications such as a microwave power source of a plasma power source that is a semiconductor manufacturing apparatus.

Configuration diagram of microwave processing apparatus according to Embodiment 1 of the present invention Sectional drawing of the electric power feeding part in Embodiment 1 of this invention

DESCRIPTION OF SYMBOLS 1a, 1c Oscillation part 2a, 2c Power distribution part 3a-3d Phase variable part 4a-4d Amplification part 5a-5d Power supply part 6a-6d Electric power detection part 7 Control part 8 Heating chamber 9 Heated object 10 Mounting base 11a, 11c Excitation Direction 12a to 12d Rotation operation part 13 Radiation part 14 Propagation part 141 Propagation part outer shaft 142 Propagation part inner shaft 143 Propagation part outer shaft tube-shaped part 144 Propagation part omission prevention 145 Propagation part bearing 15 Dielectric 16 Drive part 17 Relay part

Claims (8)

A heating chamber that accommodates an object to be heated; an oscillation unit; a power distribution unit that distributes and outputs the output of the oscillation unit; and a phase variable unit that varies at least one output phase of the power distribution unit; The power distribution unit and / or an amplification unit that amplifies the output of the phase variable unit, a radiation unit that radiates microwave power to the heating chamber, and a propagation unit that transmits the output of the amplification unit to the radiation unit A power detection unit that detects microwave power reflected from each of the power supply units in the direction of the amplification unit, a control unit that controls the oscillation frequency of the oscillation unit and the phase amount of the phase variable unit, An electric field or a magnetic field of a microwave radiated from the radiating part by the rotational operation of the radiating part, wherein the radiating part is rotatable about the propagating part as a central axis. Orientation is changed configuration of the microwave processing apparatus. The propagating part of the power feeding part is partially coaxial with the axis connected to the radiating part and the two axes of the shaft that directly or indirectly penetrates the hole provided in one wall surface constituting the heating chamber and directly or indirectly to the amplifying part. The microwave processing apparatus according to claim 1, wherein the microwave processing apparatus is combined with a shape. The two outer shafts combined in the coaxial shape constituting the propagating portion have a tube-shaped configuration having a thickness equal to or greater than the thickness at which the high-frequency current of the propagating microwave becomes 1 / e (e: the base of natural logarithm) of the surface current. Item 3. The microwave processing apparatus according to Item 1 or 2. The microwave processing apparatus according to claim 1 or 2, wherein the inner shaft is rotatably held inside two outer tube-shaped shafts combined in a coaxial shape constituting the propagation portion. The microwave processing apparatus according to claim 1 or 2, wherein the microwave processing apparatus is configured to be held so as not to pass through the inner shaft inside the two outer tube-shaped shafts combined in a coaxial shape constituting the propagation portion. 5. The micro of claim 1, wherein the two outer tube-shaped axes combined with the coaxial shape constituting the propagation portion and the inner shaft are not in contact with each other except for a portion that is rotatably held. 6. Wave processing device. The microwave processing apparatus according to claim 1 or 2, wherein the end portions of the two outer tube-shaped shafts combined in a coaxial shape constituting the propagation portion are tapered. The dielectric material which interlock | cooperates with the axis | shaft connected to the radiation | emission part or the said radiation | emission part between the radiation | emission part and the one wall surface which comprises the said heating chamber was provided, and it was set as the structure driven rotationally by the dielectric part. Microwave processing equipment.