JP5556035B2 - Microwave heating device - Google Patents

Description

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

In the conventional microwave heating apparatus of this type, there is one in which at least two antennas connected to a solid-state oscillator are generally arranged on the same wall surface of a heating chamber (see, for example, Patent Document 1). Based on this, manufacturing, that is, work at the manufacturing site is easy, productivity is high, and realization of a configuration with high serviceability is hardly considered.
Japanese Utility Model Publication No. 52-16654

  However, in the case where a plurality of antennas are arranged on the same wall surface of the heating chamber, the difference from the simple provision of a plurality of antennas is not clear, and the content of the effect of providing the same wall surface, the specific configuration There was no disclosure and only the possibility of realization was shown.

  The present invention solves the above-described conventional problems, and provides a microwave heating apparatus that takes into account a specific configuration, manufacturing technology, and manufacturing work for radiating microwaves radiated from each of a plurality of power feeding units from below. For the purpose.

In order to solve the above-described conventional problems, a microwave heating apparatus of the present invention includes a heating chamber that accommodates an object to be heated, an oscillation unit, and a power distribution unit that distributes and outputs the output of the oscillation unit to a plurality of units. A plurality of phase variable units that respectively vary a plurality of output phases of the power distribution unit; a plurality of power units that respectively amplify the power of the power distribution unit and / or the phase variable unit; and the output of the power unit is transmitted A plurality of directional couplers that detect microwave power reflected and transmitted through the power unit, and attenuate and convert the transmitted and reflected microwave power detected by the directional coupler into a DC voltage. A plurality of detection circuits configured to radiate microwave power transmitted from the directional coupler into the heating chamber and provided on a lower wall surface constituting the heating chamber. A plurality of power supply units, a control unit that controls the oscillation frequency of the oscillation unit and the phase amount of the phase variable unit according to the output of the detection circuit, and an exterior cover provided in the lower part of the heating chamber, The oscillation unit, the power distribution unit, and the plurality of phase variable units attached to the unit are unitized as a centralized system unit, the power units are arranged at four corners, and the central system unit is the power unit And mounted on the exterior cover.

  As a result, it is possible to consolidate the components and collect them into a simple semi-finished unit, which can be mounted with simple work, greatly simplifying workability and improving serviceability.

  The microwave heating apparatus according to the present invention is a system that compiles components into components, collects them as components, and collects them into a simple semi-finished unit. A microwave processing apparatus with improved performance is provided.

A first invention is 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 plurality of output phases of the power distribution unit are variable. A plurality of phase variable units, a plurality of power units each amplifying the output of the power distribution unit and / or the phase variable unit, and the microwave power transmitted through the power unit and reflected in the direction of the power unit. A plurality of directional couplers for detecting microwave power to be transmitted; a plurality of detection circuits for attenuating transmission and reflection microwave power detected by the directional coupler and converting them to DC voltage; and the heating chamber. A plurality of power feeding portions that are provided on the lower wall surface and radiate microwave power transmitted from the directional coupler into the heating chamber, and according to the output of the detection circuit, A control unit that controls the oscillation frequency of the vibration unit and the phase amount of the phase variable unit, the exterior cover provided at the lower part of the heating chamber, the oscillation unit attached to the same substrate, the power distribution unit, With a configuration in which a plurality of the phase variable units are unitized as a central concentrated system part , the power unit is arranged at four corners, and the central concentrated system part is arranged at the center of the power unit and mounted on the exterior cover, The convenience and serviceability of manufacturing can be greatly improved.

The second aspect, in the first aspect, which was a configuration of placing a sheet collecting part at regular intervals, since it is possible plurality of feeding portions be dispersed widely by the heating chamber bottom, the electromagnetic wave from the feeding unit Can easily interfere with each other, and by changing the standing wave in the heating chamber to the microwave frequency and the phase between each power feeding section, it is possible to obtain a dynamic change and to easily change the heating distribution freely. Can do.

The third aspect, in the first aspect, which was a configuration having a plurality of placing the sheet collecting portion at regular intervals and the intervals, in order to standardize parts of the unit shown here, various sizes It is necessary to make it adaptable to the heating chamber. Therefore, regarding the arrangement of the power supply unit, the position of the power supply unit can be selected according to the size of the heating chamber, and options are provided so that an optimum heating distribution can be obtained according to the size of each heating chamber.

According to a fourth aspect of the present invention, in the second or third aspect of the present invention, the drive power supply unit, the centralized central system unit, and the control unit are arranged in the gap between the power units. And improve workability in assembly work.

In the fifth invention, in particular , in any one of the first to fourth inventions, the exterior cover on which each component is mounted is attached to the bottom of the heating chamber and fastened with screws. With a simple screw tightening, it is possible to bring the product almost to the finished state, and the convenience and serviceability of manufacturing can be greatly improved.

In a sixth aspect of the invention, in particular, in the fifth aspect of the invention, a power propagation shaft attached to the power unit is passed through a hole formed in the bottom surface of the heating chamber, and an exterior cover is attached to the bottom surface of the heating chamber. By installing the unit in a detachable manner, it is possible to fix the power supply unit by simple screw tightening after the unit is attached, and to greatly improve manufacturing convenience and serviceability.

  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 heating apparatus according to the first embodiment of the present invention.

  Components will be described with reference to FIG. The oscillation unit 12 transmits an original signal in a band of 2400 MHz to 2500 MHz. The power distribution unit 13 distributes the output of the oscillation unit 12 into four. The phase variable units 11 a to 11 d control the phase of the output of each power distribution unit 13. The power units 1a to 1d have a function of amplifying the microwave power from the power distribution unit 13 and are configured using semiconductor elements. The power distribution unit 13 may be an in-phase distributor that does not generate a phase difference between outputs, such as a Wilkinson distributor, or a phase difference between outputs such as a branch line type or a rat race type. It may be the resulting distributor. Further, the power distribution unit 13 propagates approximately 1/4 of the microwave power input from the oscillation unit 12 to the power units 1a to 1d.

  In addition, the phase variable units 11a to 11d are configured by using a capacitance variable element whose capacitance changes according to the applied voltage, and each phase variable range is a range from 0 degrees to about 180 degrees. Thereby, the phase difference of the microwave power output from the phase varying units 11a to 11d can be controlled in the range of 0 degree to ± 180 degrees.

  The components so far are microwave flow power flows, but they handle relatively small power of about 10 W or less, and can be configured on the same substrate. If this part is made into one unit as the centralized system section 3, the effect of manufacturing such as reduction in the number of parts and ease of handling will be exhibited.

  For example, the oscillating portion is made of glass epoxy as a material in a region that is also handled as a relatively general-purpose component to form a substrate having a microstrip line configuration. Since the power after the power distributor 13 becomes relatively large, the substrate material is made of Teflon (registered trademark), a substrate having a microstrip line configuration, and the back surface is a ground foil, so that it becomes a base metal base plate. Integration by soldering or the like is also considered as a unitization method. Further, if the power to be handled can be made relatively low, it can be considered that a single substrate is made of a glass epoxy substrate.

  The directional couplers 19a to 19b transmit the outputs of the power units 1a to 1d and send part of the transmitted wave power and the reflected wave power to the detection circuit. The detection circuit 20 attenuates, detects, and smooths the microwave power reflected in the power unit direction and the transmitted microwave power to detect it as a DC voltage (transmitted power is Pf and reflected power is Pr). The signal is sent to the control unit 4. The detection circuit 20 will be described later in another drawing.

  The power feeding units 5 a to 5 d radiate the microwave output amplified by the power units 1 a to 1 d into the heating chamber 6. The control unit 4 controls the oscillation frequency of the oscillation unit 12 and the phase amounts of the phase variable units 11a to 11d according to Pf and Pr detected by the detection circuit 20. The drive power supply unit 2 is composed of an insulated AC-DC converter with a PFC function, and supplies voltages (Vdd, GND) to the power units 1a to 1d.

The control unit 4 determines the heating condition of the heated object directly input by the user, the load information obtained from the position detecting means for detecting the arrangement position of the heated object, or the progress state of the heating process of the heated object during the heating. Of driving power supplied to each of the oscillation unit 12 and the power units 1a to 1d, which are components of the microwave generation unit, on the basis of the heating information obtained from the processing state detection means for detecting the power and the reflected power information of the detection circuit 20 The direction of the microwave excitation electric field radiated is controlled by controlling the voltage supplied to the phase variable portions 11a to 11d, and the object to be heated housed in the heating chamber 6 is optimally heated.

  Further, the microwave heating apparatus of the present invention has a heating chamber 6 having a substantially rectangular parallelepiped structure for storing an object to be heated, and the heating chamber 6 stores a wall surface made of a metal material and an object to be heated (not shown). For this purpose, the microwave to be supplied is confined by an opening / closing door (not shown) that opens and closes and a mounting table 7 on which an object to be heated is mounted. And the microwave output which generate | occur | produced in power unit 1a-1d is propagated, and all the four electric power feeding parts 5a-5d which radiate | emit in the heating chamber 6 are arrange | positioned at the bottom wall surface which comprises the heating chamber 6. FIG. The object to be heated is heated by the microwave output radiated from the four power feeding units 1a to 1d.

  Next, the power units 1a to 1d will be described with reference to FIG. A circuit is constituted by a conductor pattern made of a low dielectric loss material and formed on one surface of a dielectric substrate. The weak microwave output output from the power distribution unit 13 is amplified by each amplification unit (preamplifier a14, preamplifier b15, preamplifier c16), and is amplified to a power of tens of W or more. This portion is referred to as a driver stage 21. Since the output stage 22 amplifies a large input power, an amplifying element having a considerably large semiconductor chip is required, and a gain of approximately 10 dB is required due to the parallel connection of the final amplifier a17 and the final amplifier b18. Here, the output stage 22 controls the function. In order to operate the microwave power semiconductor element satisfactorily, matching circuits are arranged on the input side and the output side of each semiconductor element.

  Outputs of the power units 1 a to 1 d are transmitted by the directional coupler 19. Reflection in the direction of the power units 1a to 1d also exists because it is a microwave band circuit. The detection circuit 20 is composed of an attenuator, a detection diode, a smoothing capacitor, etc., and a part of the transmitted power and reflected power is incident, and the control unit 4 can detect the detection element and the smoothing circuit by reducing the voltage to a low voltage with the attenuator. It is converted into a direct current low voltage to obtain Pr and Pf. Naturally, if the circuit pattern design is skillfully performed, the directional couplers 19a to 19d and the detection circuit 20 can be incorporated into the power units 1a to 1d. If this is realized, the circuit is integrated to reduce the total number of units. It is possible to simplify the manufacturing process.

  The operation and effect of the microwave heating apparatus configured as described above will be described below.

  FIG. 3 is a structural perspective view showing an example of the microwave heating apparatus.

  Here, all the components are arranged on the bottom surface of the heating chamber 6. The point here is that the power units 1a to 1d, the drive power supply unit 2, the centralized central system unit 3 and the control unit 4 are all fixedly mounted on the exterior cover 8 which also serves as an arrangement base, and is made into one unit. Handling is possible in this state. The exterior cover 8 transmits all the microwave power into the heating chamber 6 through the power propagation shafts 23a to 23d, and does not require consideration of radio wave leakage to the outside of the machine. Therefore, even if resin is selected, metal is selected. It's free.

  As an image of manufacturing, the power units 1a to 1d, the drive power supply unit 2, the centralized central system unit 3, and the control unit 4 are attached and integrated on the exterior cover 8. This work is assembled in advance in the sub-line and supplied to the main line, and the integrated unit is fastened to the bottom surface of the heating chamber 6 with the mounting screw 9 in the main line. Screws are inserted into the holes formed in the protruding ends of the feeding portions 5a to 5d having an antenna function made of a metal flat plate after being fitted into the holes for inserting the power propagation shafts 23a to 23d previously bored in the heating chamber 6 and fastened with the mounting screws 9. Fixing to tighten is also conceivable. This case does not limit the fixing method.

  In addition, since the integrated unit, that is, all the parts can be taken out by simply removing the screws, the serviceability is extremely good.

  As described above, the microwave heating apparatus according to the present invention can perform heat treatment at a frequency at which the microwave power reflected by a plurality of power supply portions provided on one wall surface constituting the heating chamber is minimized. The present invention can also be applied to applications such as a heating device using a dielectric heating as typified by a range, a garbage disposal machine, or a microwave power source of a plasma power source that is a semiconductor manufacturing device.

The system block diagram of the microwave heating apparatus in Embodiment 1 of this invention 1 is a circuit configuration diagram of a power unit according to Embodiment 1 of the present invention. Overview of assembly perspective view of main parts of microwave heating apparatus according to Embodiment 1 of the present invention

DESCRIPTION OF SYMBOLS 1a-1d Power unit 5a-5d Feed part 6 Heating chamber 8 Exterior cover 11a-11d Phase variable part 19a-19d Directional coupler 12 Oscillator 13 Power distribution part 20 Detection circuit

Claims (6)

A heating chamber for storing an object to be heated;
An oscillation unit;
A power distribution unit that distributes and outputs the output of the oscillation unit to a plurality of outputs;
A plurality of phase variable sections that respectively vary a plurality of output phases of the power distribution section;
A plurality of power units each for amplifying the output of the power distribution unit and / or the phase variable unit;
A plurality of directional couplers for transmitting the output of the power unit and detecting the microwave power reflected in the direction of the power unit and the transmitted microwave power;
A plurality of detection circuits for attenuating transmission and reflection microwave power detected by the directional coupler and converting them to a DC voltage;
A plurality of power feeding units that are provided on a lower wall surface constituting the heating chamber and radiate microwave power transmitted from the directional coupler into the heating chamber;
A control unit that controls the oscillation frequency of the oscillation unit and the phase amount of the phase variable unit according to the output of the detection circuit;
An exterior cover provided at the bottom of the heating chamber;
The oscillation unit, the power distribution unit, and the plurality of phase variable units attached to the same substrate are configured as a unitary central system unit ,
The microwave heating apparatus in which the power unit is disposed at four corners, and the central concentrated system portion is disposed at the center of the power unit and mounted on the exterior cover. The microwave heating apparatus according to claim 1, wherein the power feeding units are arranged at equal intervals. The microwave heating apparatus according to claim 1, wherein the power feeding units are arranged at equal intervals and have a plurality of the intervals. A clearance to the drive power supply portion between the power unit and the centralized system unit, a microwave heating apparatus according to claim 2 or 3 has a configuration to place the control unit. Microwave heating apparatus according to any one of claims 1 to said outer cover mounting the respective component parts and configured to be fastened with screws attached to the heating chamber bottom surface 4. Power propagation axes attached to the power unit is passed through a hole bored in the heating chamber bottom surface attached to the outer cover in the heating chamber bottom surface, according to claim 5 in which a detachably attaching constituting the power supply portion to the power propagation axis The microwave heating apparatus as described.