JP2008269793A - Microwave processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device to heat various heated objects efficiently by optimumly arranging a plurality of power feeding parts on a wall face of a heating room, and optimizing frequency and phase difference of a radiated microwave from the respective power feeding parts. <P>SOLUTION: A microwave generating part 1 is equipped with an oscillating part 2, an electric power distributing part 3, amplifying parts 5a, 5b, the heating room 8 to house the heated objects, the power feeding parts 7a, 7b which are arranged on the wall face of the heating room 8, to which output of the microwave generating part 1 is transmitted, and in which the microwave is radiated and supplied to the heating room 8, and phase variable parts 4a, 4b inserted into a microwave transmitting passage. By variable control of the phase difference and an oscillation frequency of the microwave output from the power feeding parts 7a, 7b, reflected electric power against the various heated objects are suppressed to the minimum, and highly efficient heating can be achieved. <P>COPYRIGHT: (C)2009,JPO&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 combines 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 the output of the amplification unit. Some have a combining unit and a phase shifter is provided between the distributing unit and the amplifying unit (for example, Patent Document 1).

  The phase shifter is configured to switch the microwave pass line length according to the on / off characteristics of the diode. In addition, 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 changed. 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 56-132793 A

  However, the microwaves radiated from the two outputs of the combining unit in the conventional configuration change the radiated power ratio and phase difference from the two radiating antennas arbitrarily and instantaneously by changing the phase by the phase shifter. Although there is a problem that 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 the radiation to a desired state. .

  The present invention solves the above-described conventional problems, and optimally arranges a plurality of power supply units having a function of radiating microwaves on a wall surface constituting a heating chamber and radiates microwaves from the respective power supply units. An object of the present invention is to provide a microwave generation processing apparatus that heats objects to be heated having various shapes, types, and amounts to a desired state by optimizing the phase difference and the oscillation frequency.

  In order to solve the conventional problems, a microwave processing device of the present invention includes an oscillation unit, a power distribution unit that distributes and outputs the output of the oscillation unit, and a phase of the output of the power distribution unit. A microwave generation unit having a variable phase variable unit, an amplifying unit for amplifying each of the outputs of the phase variable unit, and a plurality of output units for outputting the outputs of the amplifying unit, and an object to be heated are accommodated. A heating chamber, a plurality of power feeding units that supply the respective outputs of the microwave generation unit to the heating chamber, and a control unit that controls the oscillation frequency of the oscillation unit and the phase amount of the phase variable unit, The plurality of power feeding units are arranged on a plurality of different wall surfaces constituting the heating chamber, and by controlling the phase difference and frequency of the microwaves radiated from the plurality of power feeding units so that the reflected power is minimized. In the heating chamber The irradiated microwave is effectively absorbed by the object to be heated, and the microwave radiation can be directly incident on the object to be heated from different directions by performing microwave radiation from different wall surfaces. Objects to be heated of different types and amounts can be heated to a desired state.

  The microwave processing apparatus of the present invention optimally arranges a plurality of power supply units having a function of radiating microwaves on the wall surface constituting the heating chamber, and the phase difference and frequency of the microwaves radiated from each power supply unit By optimizing the above, it is possible to provide a microwave processing apparatus that heats an object to be heated of various shapes, types, and amounts to a desired state.

  The first invention includes an oscillating unit, a power distributing unit that distributes and outputs the output of the oscillating unit, a phase varying unit that varies the phase of the output of the power distributing unit, and an output of the phase varying unit A microwave generation unit having an amplification unit for amplifying each of the power and a plurality of output units for outputting outputs of the amplification unit, a heating chamber for storing an object to be heated, and the microwave generation unit in the heating chamber And a control unit that controls the oscillation frequency of the oscillating unit and the phase amount of the phase variable unit, and the plurality of power feeding units have different wall surfaces that constitute the heating chamber. The configuration is such that the phase difference and the frequency of the microwaves radiated from the power feeding unit are controlled while being arranged on a plurality of wall surfaces, and the reflected power is minimized with respect to the phase difference and the frequency of the microwaves radiated from the plurality of power feeding units. To be By controlling, the microwave radiated into the heating chamber is efficiently absorbed by the object to be heated, and the microwave radiation is directly incident on the object to be heated from different directions by performing microwave radiation from different wall surfaces. It is possible to heat objects to be heated in various shapes, types, and amounts to a desired state.

  In the second invention, in particular, a power detection unit is provided in each of a plurality of transmission paths for transmitting the output of the amplification unit of the first invention to the microwave generation unit, and reflection reflected from the microwave generation unit to the amplification unit. The control unit is configured to control the phase variable unit and the oscillation unit to the frequency and phase difference at which the reflected power is minimized, thereby suppressing the reflected power to the minimum and heating the object to be heated. It is possible to efficiently perform heating in a short time.

  In the third aspect of the invention, in particular, the control unit of the second aspect of the invention is a stage before heat-treating the object to be heated accommodated in the heating chamber, and the reflected power is minimized at a power lower than the power of the microwave to be heat-treated. By adopting a preparatory operation to detect the frequency and phase difference, even when heated objects with different shapes, types, and quantities are placed in the heating chamber, it is fatal to the amplifier due to excessive reflected power. The object to be heated can be efficiently heated without damaging it.

  In the fourth aspect of the invention, in particular, when the control unit of the second to third aspects of the invention heats the object to be heated contained in the heating chamber, the reflected power detected by the power detection unit is less than or equal to the predetermined reflected power. In addition, by adopting a configuration in which the phase amount of the phase variable unit and the oscillation frequency of the oscillation unit are variably controlled, even when heated objects of various shapes, types, and quantities are placed in the heating chamber, excessive reflected power It is possible to efficiently heat the object to be heated without inflicting fatal damage to the amplification unit, and at the same time, it is possible to maintain a phase difference and an oscillation frequency that are always below a predetermined reflected power during heating. Therefore, the object to be heated can always be efficiently heated.

  In the fifth aspect of the invention, in particular, when the control unit of the second to third aspects of the invention heat-treats the object to be heated, the phase of the reflected power detected by the power detection unit is always the lowest value. By variably controlling the phase amount of the variable part and the oscillation frequency of the oscillating part, even when heated objects of various shapes, types, and quantities are placed in the heating chamber, excessive reflected power is applied to the amplifying part. Heating of an object to be heated can be performed efficiently without inflicting fatal damage, and at the same time, the phase difference and oscillation frequency that are always below the specified reflected power can be maintained during heating, so that the object is heated. Even if the state of radio wave absorption and reflection changes due to an increase in the temperature of the object, the object to be heated can always be efficiently heated.

In the sixth aspect of the invention, in particular, the phase amount of the phase varying unit and the amount of change in the oscillation frequency of the oscillation unit of the second to fifth aspects are such that the reflected power is the minimum value when the object to be heated is heated and before the heating process. The phase amount and oscillation frequency to be searched are different during the preliminary operation, and are amplified by excessive reflected power even when heated objects of various shapes, types, and quantities are placed in the heating chamber. Heating of an object to be heated can be performed efficiently without causing fatal damage to the part, and at the same time, the phase difference and oscillation frequency that are always below the specified reflected power can be maintained during heating. Even if the state of radio wave absorption and reflection changes due to the temperature rise of the heated object, the heated object can always be efficiently heated.

  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, a microwave generation unit 1 includes an oscillation unit 2 configured using semiconductor elements, a power distribution unit 3 that distributes the output of the oscillation unit 2 into two, and a semiconductor element that amplifies the output of each of the power distribution units 3. The configured amplifying units 5a and 5b, the power feeding units 7a and 7b that radiate the microwave output amplified by the amplifying units 5a and 5b into the heating chamber, and the microwave transmission path that connects the power distribution unit 3 and the amplifying units 5a and 5b Is inserted in the microwave transmission path connecting the phase variable units 4a and 4b, the amplifying units 5a and 5b, and the power feeding units 7a and 7b to generate an arbitrary phase difference between input and output, and reflected from the power feeding units 7a and 7b. The power detection units 6a and 6b that detect power, and the control unit 10 that controls the oscillation frequency of the oscillation unit 2 and the phase amount of the phase variable units 4a and 4b according to the reflected power detected by the power detection units 6a and 6b. Structure It is.

  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. . The power supply units 7 a and 7 b that transmit the output of the microwave generation unit 1 and radiate the microwave into the heating chamber 8 are arranged on the wall surface of the heating chamber 8. In the present embodiment, a configuration is shown in which power feeding portions 7a and 7b are arranged at approximately the center of the left wall surface and the right wall surface of the opposing configuration, respectively. The arrangement of the power supply unit is not limited to the present embodiment, and a plurality of power supply units may be provided on any wall surface, or a combination such as a right wall surface and a bottom wall surface that is not an opposing surface. It doesn't matter.

  The amplifying units 5a and 5b 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 microwave transmission path connecting each functional block forms a transmission circuit having a characteristic impedance of about 50Ω by a conductor pattern provided on one side of the dielectric substrate.

  The power distribution unit 3 may be an in-phase distributor that does not generate a phase difference between outputs such as a Wilkinson distributor, or a distribution that generates a phase difference between outputs such as a branch line type or a rat race type. It can be a vessel. The power distribution unit 3 transmits approximately half of the microwave power input from the oscillation unit 2 to each output.

Further, the phase variable units 4a and 4b 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 degree to about 180 degrees. As a result, the phase difference between the microwave powers output from the phase variable units 4a and 4b can be controlled in the range of 0 degrees to ± 180 degrees.

  The power detection units 6a and 6b extract so-called reflected wave power transmitted from the heating chamber 8 side to the microwave generation unit 1 side. The power coupling degree is about 40 dB, for example. Extract the electric energy of 1/10000. Each power signal is rectified by a detection diode (not shown), smoothed by a capacitor (not shown), and the output signal is input to the control unit 10.

  Based on the heating condition (arrow 28) of the heated object directly input by the user or the heating information obtained from the heated state of the heated object during heating and the detection information from the power detection units 6a and 6b, the control unit 10 The driving power supplied to each of the oscillation unit 2 and the amplification units 5a and 5b, which are components of the microwave generation unit 1, and the voltage supplied to the phase variable units 4a and 4b are controlled and stored in the heating chamber 8. The heated object to be heated is optimally heated.

  The microwave generator 1 is provided with a heat radiating means (not shown) for radiating heat generated by the semiconductor elements provided mainly in the amplifiers 5a and 5b.

  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 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 10 that has received the heating start signal, the microwave generation unit 1 starts operating. The control means 10 operates a drive power supply (not shown) to supply power to the oscillation unit 2. At this time, the initial oscillation frequency of the oscillation unit 2 is supplied with a voltage signal set to 2400 MHz, for example, and oscillation starts.

  When the oscillating unit 2 is operated, its output is distributed approximately by the power distributing unit 3 and becomes two microwave power signals. Thereafter, the drive power supply is controlled to operate the amplifying units 5a and 5b.

  The microwave power signals are output to the power feeding units 7 a and 7 b through the amplification units 5 a and 5 b and the power detection units 6 a and 6 b that operate in parallel, and are radiated into the heating chamber 8. Each main amplifying unit at this time outputs microwave power of less than 100 W, for example, 50 W.

  When 100% of the microwave power supplied into the heating chamber 8 is absorbed by the object to be heated, the reflected power from the heating chamber 8 is eliminated, but the type, shape, and amount of the object to be heated include the object to be heated. The electrical characteristics of the heating chamber 8 are determined, and reflected power transmitted from the heating chamber 8 side to the microwave generating unit 1 side is generated based on the output impedance of the microwave generating unit 1 and the impedance of the heating chamber 8.

The power detectors 6a and 6b detect the reflected power transmitted to the microwave generation unit 1 and detect a signal proportional to the amount of reflected power. The control unit 10 receiving the detection signal Select the oscillation frequency and phase difference at which the power is minimal. In response to the selection of the frequency and the phase difference, the control unit 10 increases the oscillation frequency of the oscillation unit 2 from the initial 2400 MHz, for example, at a 1 MHz pitch, with the phase difference generated by the phase variable units 4a and 4b being 0 degrees. The phase difference generated by the phase variable units 4a and 4b is changed to, for example, 30 degrees, and this time, the upper limit of the frequency variable range is changed from 2500 MHz to 1 MHz pitch. Change to the side. When the oscillation frequency reaches 2400 MHz, the phase difference between the outputs of the phase variable units 4a and 4b is changed again (for example, 60 degrees), and the oscillation frequency of the oscillation unit 2 is changed again from 2400 MHz to 2500 MHz. By performing this operation, the control unit 10 can obtain an array of reflected power with respect to the oscillation frequency of the oscillation unit 2 and the phase difference between the phase variable units 4a and 4b. The control unit 10 controls the oscillation unit 2 and the phase variable units 4a and 4b having the smallest reflected power under the phase difference condition and controls the oscillation output so as to obtain an output corresponding to the input heating condition. Thereby, each amplification part 5a, 5b outputs predetermined microwave electric power, respectively. Each output is transmitted to the power feeding units 7 a and 7 b and radiated into the heating chamber 8.

  By operating in this way, heating can be started under the condition that the reflected power is minimized even for objects to be heated having various shapes, sizes, and quantities, and the semiconductors provided in the amplification units 5a and 5b It is possible to prevent the element from excessively generating heat due to the reflected power and to avoid thermal destruction.

  FIG. 2 is a flowchart showing a control example of the phase difference of the phase variable units 4a and 4b and the oscillation frequency of the oscillation unit 2 during the heating operation. First, control is performed so that the phase difference is shifted by ΔΦ (for example, 5 degrees) from the state in which the phase variable units 4a and 4b are operating in a state where the phase difference is caused by the phase difference Φ. At this time, the power detection units 6 a and 6 b each measure the reflected power and transmit a signal corresponding to the amount of reflected power to the control unit 10. The control unit 10 compares the reflected power measured last time with the reflected power measured this time. If the reflected power decreases, ΔΦ is left as it is, and if the reflected power increases, the sign of ΔΦ is reversed. By doing so, it is possible to always control the reflected power to decrease in response to the change in the phase difference Φ. Also, the oscillation frequency f is controlled in the same manner, that is, the oscillation frequency is shifted by Δf (for example, 0.1 MHz) while the oscillation unit 2 is oscillating at a certain oscillation frequency f, and the reflected power at that time is controlled. Measure. The control unit 10 compares this reflected power with the reflected power measured last time (before changing the oscillation frequency). If the reflected power is reduced, Δf is set as it is, and if the reflected power is increased, Δf. The sign of is reversed. By this operation, the reflected power can be controlled to always decrease with respect to the change of the oscillation frequency.

  By controlling in this way, the power detection units 6a and 6b can detect the reflected power from the heating chamber 8 even during the heating operation, so the control unit 10 determines this and minutely determines the oscillation frequency and phase difference. Since the state where the reflected power is always kept low can be adjusted, the heat generation of the semiconductor element can be further suppressed, and the heating efficiency can be maintained high, so that heating in a short time can be achieved. Alternatively, the allowable reflected power is set to a predetermined value, and the control unit 10 can temporally change the phase difference between the phase variable units 4a and 4b and the oscillation frequency of the oscillating unit 2 within the allowable reflected power range. By performing such an operation, the propagation state of the microwave in the heating chamber 8 can be changed with time, so that local heating of the object to be heated can be eliminated and the heating can be made uniform. is there.

  In the present embodiment, an example in which two phase variable units are inserted has been described. However, the phase change unit is inserted only into one of the outputs of the power distribution unit 3 so that the phase change width is 0 degrees to 360 degrees. It can also be configured.

  As described above, the microwave processing apparatus according to the present invention includes a device that has a plurality of power supply units, controls the power supply units that radiate microwaves, and changes the microwave phase difference between the power supply units in operation. Since it can be provided, it can be applied to applications such as a microwave power source of a plasma power source that is a heating device, a garbage disposal machine, or a semiconductor manufacturing device using dielectric heating as typified by a microwave oven.

Configuration diagram of microwave processing apparatus according to Embodiment 1 of the present invention Flow chart showing control example of phase difference and oscillation frequency of the microwave processing apparatus

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Microwave generation part 2 Oscillation part 3 Power distribution part 4a, 4b Phase variable part 5a, 5b Amplification part 6a, 6b Electric power detection part 7a, 7b Feeding part 8 Heating chamber 10 Control part

Claims (6)

A heating chamber that houses an object to be heated, an oscillation unit, a power distribution unit that distributes and outputs the output of the oscillation unit, a phase variable unit that varies the phase of the output of the power distribution unit, and the phase An amplifying unit that amplifies the output of each variable unit, a plurality of power feeding units that supply the output of the amplifying unit to the heating chamber, and a control unit that controls the oscillation frequency of the oscillating unit and the phase amount of the phase varying unit The plurality of power feeding units are arranged on a plurality of different wall surfaces constituting the heating chamber, and the control unit controls a phase difference and a frequency of microwaves radiated from the power feeding unit, and Microwave processing equipment. A power detection unit is provided in each of a plurality of transmission paths that transmit the output of the amplification unit to the power supply unit, detects reflected power reflected from the power supply unit to the amplification unit, and the control unit minimizes the reflected power. The microwave processing apparatus according to claim 1, wherein the phase variable unit and the oscillation unit are controlled by a frequency and a phase difference. The control unit is configured to perform a preliminary operation to detect a frequency and phase difference at which reflected power is minimized at a power lower than the power of the microwave to be heat-treated before the object to be heated is heat-treated. The microwave processing apparatus according to claim 2. When the control unit heats the object to be heated contained in the heating chamber, the phase amount of the phase variable unit and the oscillation frequency of the oscillating unit are variable so that the reflected power detected by the power detection unit is equal to or lower than the predetermined reflected power. The microwave processing apparatus according to claim 2 or 3 configured to be controlled. The control unit variably controls the phase amount of the phase variable unit and the oscillation frequency of the oscillation unit so that the reflected power detected by the power detection unit is always the lowest value when the object to be heated housed in the heating chamber is heated. The microwave processing apparatus according to claim 2 or 3, wherein the microwave processing apparatus is configured. The amount of phase change of the phase variable unit and the amount of change of the oscillation frequency of the oscillating unit are the values when the object to be heated is heat-treated and during the preliminary operation for searching for the phase amount and oscillation frequency at which the reflected power becomes the minimum value before the heat treatment The microwave processing apparatus according to any one of claims 2 to 5, wherein the microwave processing apparatus is different.

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