JP2019008903A - Plasma generator - Google Patents

Abstract

To provide a plasma generator equipped with an electromagnetic wave oscillator largely reduced in size as compared to a conventional semiconductor electromagnetic wave oscillator by using a semiconductor material with a high energy efficiency as a power device operable to oscillate electromagnetic waves.SOLUTION: A plasma generator comprises: an electromagnetic wave oscillator MW using, as a semiconductor material, silicon carbide, gallium nitride, gallium oxide or diamond, having an energy efficiency of 70% or more, and having an electromagnetic wave oscillation pattern according to a pulse oscillation method; an electromagnetic wave discharger 5 which raises a potential difference of a discharge gap by voltage-boosting means for raising, in voltage, electromagnetic waves supplied from the electromagnetic wave oscillator MW to cause a discharge and produce a breakdown plasma; and a controller 4 for controlling electromagnetic oscillation from the electromagnetic wave oscillator 5 in a pulse mode.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a plasma generation apparatus, and more particularly to an apparatus for generating plasma by boosting electromagnetic waves, and by using an energy-efficient semiconductor material as a power device that oscillates electromagnetic waves, it is significantly smaller than conventional semiconductor electromagnetic wave oscillators. The present invention relates to a plasma generation apparatus provided with a structured electromagnetic wave oscillator.

Plasma generated by the plasma generator reduces or reduces harmful emissions (CO ₂ , NOX, unburned hydrocarbons), volatile hazardous chemicals (VOC), suspended particulate matter (PM), soot, Used in the field of environmental measures (implants, end-of-pipe) such as tar, sludge, wastewater treatment and reuse, as well as in medical and hygiene fields such as sterilization, sterilization, and cleaning technology, as well as for surface modification of substances such as printed materials It is done.

  Generally, as a device for generating plasma, a device for generating plasma by corona discharge or barrier discharge is used, and many devices have been put into practical use. The inventor has proposed a device for generating a breakdown plasma by boosting electromagnetic waves, particularly microwaves, using a resonance circuit. This breakdown plasma is also used in an ignition device, and a technique for maintaining and expanding the breakdown plasma by irradiating the generated plasma with microwaves is also proposed.

  As an electromagnetic wave oscillator for generating an electromagnetic wave (microwave), a magnetron is generally used. However, the magnetron has a problem that the output and frequency are not stable and the oscillation mode of electromagnetic waves cannot be finely controlled. Therefore, in recent years, an electromagnetic wave oscillator using a semiconductor device has been put into practical use.

  In general, silicon is used as a semiconductor material used as an electromagnetic wave oscillator using these semiconductor devices.

  The present inventor has proposed a plasma generation apparatus that uses a semiconductor device as an electromagnetic wave oscillator and generates a breakdown plasma only with an electromagnetic wave using a booster circuit (see, for example, Patent Document 1).

International Publication No. 2014/115707

A semiconductor device using silicon as a semiconductor material is used in many products, has good availability, and is manufactured at a relatively low cost. However, a semiconductor device using silicon has high on-resistance (Ω · m ² ) with respect to breakdown voltage (breakdown voltage) and low energy efficiency (energy density). If the energy efficiency is low, electric energy is converted into heat, so that a large heat dissipation means is required, the electromagnetic wave oscillator becomes large, and it is difficult to reduce the size of the entire plasma generating apparatus.

  The present invention has been made in view of such a point, and the object thereof is a plasma generation apparatus that generates plasma using electromagnetic waves, particularly microwaves, by using an electromagnetic wave oscillator with high energy efficiency. The present invention is to provide a plasma generating apparatus that is small and can be easily transported manually.

The plasma generating apparatus of the first invention made to solve the above problems is as follows.
An electromagnetic wave oscillator that uses silicon carbide, gallium nitride, gallium oxide or diamond as a semiconductor material, has an energy efficiency of 70% or more, and an electromagnetic wave oscillation pattern is a pulse oscillation system;
An electromagnetic wave discharger that generates a breakdown plasma by increasing a potential difference of a discharge gap by a boosting unit including a resonance circuit that boosts an electromagnetic wave supplied from the electromagnetic wave oscillator; and
And a control device that controls electromagnetic oscillation from the electromagnetic wave oscillator in a pulse mode.

  In the plasma generator of the present invention, the semiconductor material of the electromagnetic wave oscillator has a low on-resistance with respect to a withstand voltage and high energy efficiency as compared with silicon, so that a small and highly efficient electromagnetic wave oscillator is formed. Can be generated.

The plasma generating apparatus of the second invention made to solve the above problems is as follows.
An electromagnetic wave oscillator that uses silicon carbide, gallium nitride, gallium oxide or diamond as a semiconductor material, has an energy efficiency of 70% or more, and an electromagnetic wave oscillation pattern is a pulse oscillation system;
An electromagnetic wave discharger that raises the potential difference of the discharge gap by a boosting means comprising a resonance circuit that boosts the electromagnetic wave supplied from the electromagnetic wave oscillator that generates the breakdown plasma, and generates a discharge. A breakdown plasma generator composed of a high voltage discharger or a laser irradiator that raises the potential difference and generates discharge;
An electromagnetic wave irradiator that irradiates the plasma generated by the breakdown plasma generator with an electromagnetic wave supplied from the electromagnetic wave oscillator;
And a control device that controls electromagnetic oscillation from the electromagnetic wave oscillator in a pulse mode.

  The plasma generating apparatus of the present invention can maintain and expand the generated breakdown plasma by injecting electromagnetic wave (microwave) energy into the generated breakdown plasma.

  In this case, a mechanism for detecting the pressure and / or temperature of the breakdown plasma generation region is provided, and the control device changes the electromagnetic wave oscillation pattern of the electromagnetic wave irradiation device in accordance with the pressure and / or temperature detected by the detection mechanism. It can be varied to maintain the plasma.

  Further, in these cases, the electromagnetic wave oscillator can be a general type.

  The present invention relates to a plasma generating apparatus that generates plasma using electromagnetic waves, particularly microwaves, by using an electromagnetic wave oscillator with high energy efficiency, and is small and can be easily transported by hand Can be provided.

(A) is a schematic block diagram of the plasma generator concerning 1st invention, (b) is a schematic block diagram of the plasma generator concerning 2nd invention. 1 is a table and graph showing characteristics of a semiconductor material used for an electromagnetic wave oscillator of the plasma generator of Embodiment 1, wherein (a) is a performance index (band gap (Eg), electron transfer speed (μe), breakdown electric field) compared with silicon. Strength (Ec) and Barriga figure of merit (BFM)), (b) shows the breakdown voltage and on-resistance compared to silicon. The electromagnetic wave discharger used for the plasma generator of Embodiment 1 is shown, (a) is a whole sectional view, (b) is a top view of an electrode part, (c) is a front view of a partly notched electrode part. . It is the schematic of the electromagnetic wave discharger used for the plasma generation apparatus of Embodiment 2, (a) is the schematic of a 1st board | substrate, (b), (c) is the schematic of an intermediate board, (d) is the 2nd board | substrate. (E) is sectional drawing of the state accommodated in the case, (f) is a front view. The other example of the electromagnetic wave discharger used for the plasma production apparatus of Embodiment 2 is shown, (a) is a front view, (b) is AA sectional drawing of (a), (c) is a side view, (d) FIG. 3 is a perspective view showing a resonance electrode. The equivalent circuit of the pressure | voltage rise means of a plasma generator is shown, (a) is the equivalent circuit of Embodiment 1, (b) is the equivalent circuit of Embodiment 2-3. (A) is a schematic block diagram of another example of the plasma generating apparatus according to the second invention, and (b) is a schematic block diagram of still another example of the plasma generating apparatus according to the second invention. It is a schematic block diagram of the plasma production apparatus concerning a 3rd invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

<Embodiment 1> Plasma Device Embodiment 1 is a plasma generating device according to the first invention as shown in FIG. A plasma generating apparatus that generates a breakdown plasma by boosting electromagnetic waves requires an electromagnetic wave oscillator MW that generates electromagnetic waves as its main component. The electromagnetic wave oscillator MW is supplied with power from the electromagnetic wave power source P and is controlled by the control device 4 to operate. The electromagnetic wave generated by the electromagnetic wave oscillator MW is sent to an electromagnetic wave discharger 5 including a booster circuit (high voltage supply means) and a discharge electrode, and plasma is generated between the discharge electrode and the ground electrode.

  The second embodiment is a plasma generating apparatus according to the second invention as shown in FIG. The electromagnetic wave oscillator MW is supplied with power from the electromagnetic wave power source P and is controlled by the control device 4 to operate. The electromagnetic wave generated by the electromagnetic wave oscillator MW is sent to the electromagnetic wave dischargers 3 and 9 including a booster circuit (high voltage supply means), a discharge electrode and an electromagnetic wave irradiator, and plasma is generated between the discharge electrode and the ground electrode, and further discharged. After the impedance mismatch occurs, the antenna part 31a of the electromagnetic wave discharger 3 and the antenna part 92a of the electromagnetic wave discharger 9 serve as an electromagnetic wave irradiator and maintain and expand the generated plasma.

  In the plasma generators of the first and second embodiments, in addition to the electromagnetic wave dischargers 3, 5, and 9 described above, a high voltage discharger or a laser irradiator functions as a breakdown plasma generator. The high voltage discharger is, for example, a spark plug (see FIG. 7A) to which a high voltage is supplied from a high voltage power source and an ignition coil (high voltage supply means). The laser irradiator is a laser oscillation device (see FIG. 7B) including, for example, a laser light source, an optical fiber, and a laser probe. The laser light source is not particularly limited, and an Nd-YAG (Neodymium-Yttrium Aluminum Garnet) laser light source or the like can be used. When a laser irradiator is used, a laser is irradiated on the surface of the object, and breakdown plasma is generated on the surface of the object.

As this electromagnetic wave oscillator MW, a magnetron is generally used, but in recent years, an electromagnetic wave oscillator using a semiconductor device has been put into practical use. A semiconductor material commonly used as a semiconductor device is silicon (silicon (Si)). A semiconductor device using silicon is manufactured from a silicon wafer made by further processing a high-purity silicon manufactured by reducing and scavenging oxide SiO ₂ . A manufacturing method of this silicon wafer has been established and is widely used as a semiconductor material because it can be mass-produced.

In the plasma generating apparatus of this embodiment, silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga ₂ O ₃ ), or diamond is used as a semiconductor material used for the electromagnetic wave oscillator MW. The electromagnetic wave oscillator MW has an energy efficiency of 70% or more and an electromagnetic wave oscillation pattern is a pulse oscillation system. The electromagnetic wave supplied from the electromagnetic wave oscillator MW is boosted in the electromagnetic wave discharger 5 by a booster circuit serving as a booster unit including a resonance circuit. By this boosting, the potential difference of the discharge gap is increased in the discharge electrode, and discharge is generated to generate breakdown plasma. The control device 4 controls the oscillation of the electromagnetic wave oscillator MW in the pulse mode.

  If the performance of the semiconductor material (semiconductor material) used is high, that is, if the energy efficiency (energy density) is high, the semiconductor device constituting the electromagnetic wave oscillator MW can be reduced in size when generating the same output. Examples of the performance index of the semiconductor material include a band gap (Eg), an electron transfer rate (μe), a breakdown electric field strength (Ec), and a barriger performance index (BFM) (see FIG. 2A). Further, as is apparent from FIG. 2B in which the inverse of the bariga performance index is graphed, silicon carbide, gallium nitride, gallium oxide, and diamond have the same on-resistance value compared to silicon. The withstand voltage (breakdown voltage) is very high. Note that FIG. 2B shows the on-resistance with respect to the withstand voltage (breakdown voltage). Normally, when the withstand voltage is increased, the internal resistance increases and the amount of heat generation also increases. Silicon carbide, gallium nitride, gallium oxide, and diamond have orders of magnitude performance of about 340 times, 870 times, 3500 times, and 54000 times that of silicon, respectively, in terms of the bariga performance index. When a semiconductor material having a high withstand voltage at the same on-resistance value is applied to the electromagnetic wave oscillator MW, for example, a λ / 4 line necessary for oscillating an electromagnetic wave (microwave) having a frequency of 2.45 GHz is thinner and smaller. It becomes possible to design at intervals, and the substrate size can be greatly reduced.

As described above, by using silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga ₂ O ₃ ) or diamond having a high Barriga performance index as a semiconductor material constituting the electromagnetic wave oscillator MW, as described above, The size can be reduced, and the volume as an electromagnetic wave oscillator can be greatly reduced. Thereby, the plasma generating apparatus including the electromagnetic wave oscillator MW can be made portable. As a result, various applications to be described later using the plasma generation apparatus of the present invention, for example, an optical analysis apparatus for measuring soil contents can be configured as a small and light portable analysis apparatus.

  In this plasma generation apparatus, the generated breakdown plasma can be maintained and expanded by injecting electromagnetic wave (microwave) energy into the breakdown plasma generated by the breakdown plasma generator. In this case, as shown in FIG. 8, the control device 4 includes a detection mechanism for the pressure and / or temperature of the breakdown plasma generation region PA, and the control device 4 generates an electromagnetic wave according to the pressure and / or temperature detected by the detection mechanism. The electromagnetic wave oscillation pattern of the irradiator can be changed to maintain the plasma. That is, it has a feedback function for maintaining the breakdown plasma even if the pressure or temperature of the breakdown plasma is deviated. Specifically, when the pressure in the plasma generation region increases, it becomes difficult to maintain the plasma. Therefore, the output of the oscillating electromagnetic wave is increased or the duty ratio of pulse oscillation is increased. In addition, breakdown plasma is generally more easily generated in a low-pressure environment than in a high-pressure environment, but there is a pressure zone in which a high pressure is easier to generate than a low pressure at a predetermined pressure. In addition, regarding the temperature, the maintenance of the breakdown plasma becomes more difficult as the temperature becomes higher as the pressure is increased.

  Moreover, the plasma generation apparatus of this invention can set arbitrary radicals and electron temperature densities arbitrarily, and can make a breakdown arbitrarily. Here, “arbitrary” means that the temperature, pressure, moisture, and concentration of the mixed gas can be set arbitrarily.

<Electromagnetic wave discharger>
As described above, the electromagnetic wave discharger 5 raises the potential difference of the discharge gap by the booster circuit composed of the resonance circuit that boosts the electromagnetic wave supplied from the electromagnetic wave oscillator MW, thereby generating discharge and generating breakdown plasma. . Specifically, as shown in FIG. 3, an input unit 52 that receives the supply of electromagnetic waves oscillated from the electromagnetic wave oscillator MW, a boosting means 50 that boosts the input electromagnetic waves, and a discharge electrode 55a that forms a discharge gap G. And a ground electrode 51a, and the voltage boosting means 50 increases the potential difference of the discharge gap G to cause discharge.

  The discharge electrode 55a is formed at the tip of an electrode shaft portion 55b extending from the bottomed tubular portion 54 through which the input shaft portion 53 extending from the input portion 52 is inserted to the side opposite to the input portion. An input shaft portion 53 extending from the input portion 52 is insulated from the cylindrical portion 54. Specifically, a cylindrical insulator 59 is interposed between the inner peripheral surface of the cylindrical portion 54. By constituting the insulator 59 so as not to be in contact with the inner peripheral surface of the cylindrical portion 54, the cylindrical portion 54 and the input shaft portion 53 are capacitively coupled, and form an equivalent circuit C1 described later. Further, the cylindrical portion 54 and the electrode shaft portion 55 b are also electrically insulated from the inner peripheral surface of the front end side casing 51 </ b> A of the casing 51. In the present embodiment, the cylindrical portion 54 and the electrode shaft portion 55 b are enclosed in a cylindrical insulator 59. An equivalent circuit C2 described later is formed between the outer peripheral surface of the cylindrical portion 54 and the inner peripheral surface of the casing 51A covering the cylindrical portion 54, and between the electrode shaft portion 55b and the inner peripheral surface of the casing 51A. An equivalent circuit capacitor C3 is formed. The resonance frequency is adjusted by the dielectric constant that varies depending on the type of the insulator 59. In addition, C1 mentioned above can also be abbreviate | omitted by connecting the input shaft part 53 with the cylindrical member 54 electrically.

  The casing 51B on the rear end side of the casing 51 has a through hole. An input portion 52 that receives an electromagnetic wave from the electromagnetic wave oscillator MW is formed at one end of the casing 51B, and an input shaft portion 53 that extends from the input portion 52 is formed at the other end. A cylindrical insulator 59 is disposed, and a discharge electrode 55a, a cylindrical portion 54, an electrode shaft portion 55b, and a casing 51A including an insulator 59 covering them are incorporated. The method of incorporating the input portion 52, the input shaft portion 53, and the casing 51A of the insulator 59 covering them is not particularly limited, but in the present embodiment, it corresponds to the outer peripheral surface of the insulator 59 and the through hole of the casing 51B. The step is inserted from the left side in the drawing to engage the insulator with the step to prevent falling off to the right side, and the casing 51A is inserted from the left side to cover the input portion 52, the input shaft portion 53, and these. The falling of the insulator 59 to the left side is also prevented. Although the method for fixing the casing 51A to the casing 51B is not particularly limited, in the present embodiment, the fixing is performed by screwing the male screw portion engraved on the outer peripheral surface of the casing 51A into the female screw portion engraved in the through hole. To do. After fixing by screwing, the casing 51A can be securely fixed to the casing 51B using a fixing means such as welding, or can be fixed using a fixing means such as welding without forming a threaded portion. it can.

  The ground electrode 51a is formed at the tip of a cylindrical casing 51A that covers the discharge electrode 55a, and forms a discharge gap G between the inner surface of the ground electrode 51a and the outer surface of the discharge electrode 55a. As shown in FIG. 3B, the ground electrode 51a (the tip of the casing 51A) that forms the discharge gap G forms a slit s. This slit s guides the air-fuel mixture into the discharge gap G and improves the combustion efficiency. The distance of the discharge gap G is preferably set in the range of 0.2 to 1.2 mm.

  The boosting means 50 is constituted by an equivalent circuit shown in FIG. The step-up means 50 uses the electrode shaft portion 55b as a coil L, forms a resonance structure at three positions between the capacitors C1, C2, and C3 described above, and steps up the supplied electromagnetic wave. In particular, the first resonance region by the capacitor C2 formed between the outer peripheral surface of the cylindrical portion 54 and the inner peripheral surface of the casing 51 that covers the cylindrical portion 54, and the casing 51 that covers the electrode shaft portion 55b and the electrode shaft portion 55b. By boosting the supplied electromagnetic wave by the second resonance region formed by the capacitor C3 between and the discharge electrode 55a, the potential difference between the discharge electrode 55a and the ground electrode 51a is increased to several tens of kV to cause discharge. Yes. In addition, it can also be set as the structure which does not form C1 of an equivalent circuit by electrically connecting the input shaft part 53 and the cylindrical part 54, and not carrying out capacitive coupling.

In general, even if an electromagnetic wave having a frequency deviating from the resonance frequency in the resonance region, particularly the second resonance region, is supplied, the potential difference between the discharge electrode 55a and the ground electrode 51a cannot be increased by boosting the electromagnetic wave. It is determined by so-called Q value whether the frequency can be boosted by supplying a frequency deviating from the resonance frequency determined in the resonance region. What is Q value?
Q = ω ₀ / (ω ₁ −ω ₂ ).
Here, ω ₀ : resonance frequency, ω ₁ and ω ₂ (ω ₁ > ω ₂ ): frequencies at which the energy at frequency ω ₀ is halved. Therefore, as the values of ω ₁ and ω ₂ are closer to ω ₀ , the resonance peak becomes sharper, the Q value becomes larger, a large energy can be obtained, and it is generally desirable to design the Q value to be larger. . However, when the Q value is large, in order to resonate, the deviation from the resonance frequency determined in the resonance region cannot be made large. According to the experiments by the present inventors, when the Q value is about 50, an electromagnetic wave having a frequency in the range of ± 30 Hz, more preferably ± 20 Hz, can be resonated and discharged.

The electromagnetic wave oscillator MW is always supplied with a predetermined voltage, for example, 12 V from the electromagnetic wave power source P. Then, an electromagnetic wave (for example, 2.45 GHz microwave) is output from the control device 4 as a pulse wave of an oscillation pattern in which an electromagnetic wave oscillation signal is set with a predetermined duty ratio, pulse time, and the like. At this time, the oscillation frequency is set to the above-described resonance frequency ω ₀ , and the resonance frequency varies depending on temperature, pressure, and other factors. Therefore, in the present embodiment, the reflected wave is detected by the monitoring device (S11 monitoring) controlled by the control device 4 and controlled so as to have an optimum oscillation frequency. Specifically, control is performed so that the value of the reflected wave is equal to or less than a threshold value. This control interval can be performed at an interval of 1 MHz (1 μsec) because a semiconductor oscillator is used. This enabled high-speed feedback control.

<Embodiment 2> Plasma generator The second embodiment is a plasma generator according to the second invention as shown in FIG.

<Electromagnetic wave discharger 9>
FIG. 4 shows an example of an electromagnetic wave discharger used in the plasma generation apparatus of the second embodiment. The electromagnetic wave discharger 9 is configured by forming a predetermined pattern on a plurality of insulating substrates and laminating them. The insulating substrate has a rectangular shape, and an input terminal portion is formed at one end and a plasma generation portion (discharge portion) is formed at multiple ends.

The insulating substrate is formed by firing a powder (hereinafter referred to as a ceramic raw material) of ceramics (for example, alumina (Al ₂ O ₃ ), aluminum nitride, cordierite, mullite, etc.). In this embodiment, a single-layer ceramic insulating substrate can be used. Specifically, a uniform slurry is produced by adding a binder / solvent to the ceramic raw material and mixing and grinding. Thereafter, the mixture is granulated by spray drying (spray drying) to form granules. The granules are formed into a ceramic molded body having a desired shape by CIP molding (cold isostatic pressing), press molding, injection molding or the like, and then fired in a firing furnace. CIP molding is suitable for molding small plate-like bodies by placing granules in a rubber mold and molding using water pressure, and press molding is a process for placing granules in a mold and molding. This is the most suitable method for forming the insulating substrate having the form. Further, the insulating substrate may be a resin plate such as a fluororesin or a glass epoxy material in addition to the above-described materials.

  The center electrode 92 formed on the insulating substrate and the resonance electrode 93 constituting the discharge electrode 93a are made of a conductive paste whose main component is metal powder (for example, silver, copper, tungsten, molybdenum, etc. having low electric resistance) as shown in FIG. Although printing is performed on an insulating substrate by a technique such as screen printing so as to obtain a configuration as shown in a) and (d), the present invention is not limited to this.

  The electromagnetic wave discharger 9 is configured such that four substrates are stacked and accommodated in a hollow prismatic case 90. The substrates 91B and 91C, which are intermediate substrates, are one substrate in consideration of the thickness. Can also be configured.

  The first substrate 91A has a central electrode 92 formed on the main surface, an input unit 95 (for example, an SMA connector) connected to an external electromagnetic wave oscillator MW at one end of the short side, and a predetermined thickness and length at multiple ends. An antenna portion 92a having a thickness is provided.

  The second substrate 91D includes a resonance electrode 93. The resonance electrode 93 includes a discharge portion 93a, a resonance portion 93b, and a connecting portion 93c that electrically connects the discharge portion 93a and the resonance portion 93b. The discharge part 93a is configured so as to face the antenna part 92a when stacked. Further, both sides of the discharge portion 93a are provided with notches so that the ground electrode portion 90a formed at the end portion of the case 90 enters when the substrate laminated on the case 90 is stored. As a result, the short side where the discharge part 93a is formed becomes convex.

  In the above configuration, an electromagnetic wave (2.45 GHz microwave in this embodiment) supplied from the external electromagnetic wave oscillator MW is transmitted from the antenna portion 92a of the center electrode 92 to the resonance portion 93b of the resonance electrode 93 via the discharge portion 93a. As a result, the voltage is increased and the potential difference between the discharge portion 93a of the resonance electrode 93 and the ground electrode 90a is increased. As a result, primary plasma SP1 is generated between the discharge part 93a and the ground electrode 90a. The antenna portion 92a and the discharge portion 93a form a capacitor that is capacitively coupled.

  The generation of the primary plasma SP1 causes impedance mismatch, but electromagnetic waves passing through the center electrode 92 not passing through the resonance part are supplied from the antenna part 92a to the primary plasma SP1, and the primary plasma SP1 is maintained. Enlarged. The plasma generated in this way improves the adhesion of ink by modifying the surface of the substrate T on the upstream side of the ink cartridge 2 of the printing apparatus, as in the first embodiment.

  FIG. 6B is an equivalent circuit of the boosting means of this embodiment. When no plasma is generated, both ends of the resistors Rp1 and Rp2 are considered to be equivalent to the released state. When an electromagnetic wave (microwave) is input from the external electromagnetic wave oscillator MW, first, a current flows through the capacitor C1. When a strong resonance current flows through the loop circuit formed by the capacitors C2 and C3 and the reactance L in resonance with the frequency of the supplied electromagnetic wave, a high voltage is generated particularly at both ends of the capacitor C3. Dielectric breakdown occurs at both ends of the capacitor C3, and discharge occurs to generate plasma (this corresponds to the above-described primary plasma SP1). At both ends of the capacitor C3, the resistor Rp1 is changed from the released state to the state connected in parallel. In this state, as in the step-up unit of the first embodiment shown in FIG. 6A, the impedance mismatching occurs, so that the reflected wave becomes large. Next, discharge is generated between the transmission line and the plasma SP1 generated at both ends of the capacitor C3 as a seed. As a result, a strong current flows between the transmission line and the ground (GND) (in terms of electrical circuit, the resistor Rp2 is connected from the open state). However, since the discharge through the path directly connected to the transmission line does not go through the resonance portion (the resonance portion 93b of the resonance electrode 93), the amount of reflection due to impedance mismatching is greatly reduced. Thereby, input electric power can be given to plasma with high efficiency.

<Electromagnetic wave discharger 3>
FIG. 5 shows another example of the electromagnetic wave discharger used in the plasma generation apparatus of the second embodiment. As shown in FIG. 5, the electromagnetic wave discharger 3 is connected to a hollow cylindrical case 30 and an input unit 33 that is substantially coaxial with the case 30 and connected to an external electromagnetic wave oscillator MW at one end. A central electrode 31 having an antenna portion 31a that radiates electromagnetic waves supplied from the input portion 33 is formed at the other end, and a shaft portion 31b having a smaller diameter than the antenna portion 31a connecting the antenna portion 31a of the central electrode 31 and the input portion 33 is covered. The shield electrode 33 includes a resonance electrode 32 including a discharge part 32 a covering the antenna part 31 a and a cylindrical resonance part 32 b covering the shield pipe 33. Then, the electromagnetic wave supplied from the resonance unit Re is boosted to increase the potential difference between the discharge unit 32a and the ground electrode 30a formed at the tip of the case 30, and the primary plasma SP1 is generated. The process until the primary plasma SP1 is generated is the same as that of the electromagnetic wave discharger 9 described above.

  Although the discharge part 32a which covers the antenna part 31a which comprises the resonant electrode 32 may be a cylindrical part, as shown in FIG.5 (d), it is comprised so that it may become a semicircle shape. And the discharge part 32a and the resonance part 32b are connected by the connection part 32c which notched leaving the circular arc part of about 15 thru | or 30 degrees. As is apparent from the figure, the resonance electrode 32 is manufactured by cutting out a thin cylindrical metal material. The ground electrode 30a formed at the tip of the case 30 is preferably formed with a plurality of notches (slits) as shown in FIGS. 5B to 5C, thereby generating a plasma ball. Can grow greatly.

  The shield pipe 33 is a shield for preventing the electromagnetic wave supplied from the shaft part 31 b to the resonance part 32 b from being capacitively coupled, and is electrically insulated from the center electrode 31 and the resonance electrode 32. One end of the shield pipe 33 is formed integrally with the input portion 33 and is fixed to the anti-ground electrode side of the case 30. A ceramic pipe, ceramic powder, or the like may be filled as an insulator between the inner peripheral surface of the shield pipe 33 and the outer peripheral surface of the center electrode 31 for insulation. Further, it is preferable to provide an insulating pipe between the outer peripheral surface of the shield pipe 33 and the inner peripheral surface of the resonance part 32b. The insulating pipe is provided with a step on the inner peripheral surface of the case 30 so that the resonance electrode 32 can be positioned. It is preferable to arrange the insulating pipe 34 along the shape of the gap between the outer peripheral surface of the shield pipe 33 and the inner peripheral surface of the resonance part 32b.

  In the above configuration, an electromagnetic wave (2.45 GHz microwave in this embodiment) supplied from the external electromagnetic wave oscillator MW is transmitted from the antenna portion 31a of the center electrode 31 to the resonance portion 32b of the resonance electrode 32 via the discharge portion 32a. The voltage is boosted by the resonance portion Re formed between the outer peripheral surface and the inner peripheral surface of the case 30, and the potential difference between the discharge portion 32a of the resonance electrode 32 and the ground electrode 30a is increased. As a result, primary plasma SP is generated between the discharge part 32a and the ground electrode 30a. The antenna unit 31a and the discharge unit 32a form a capacitor that is capacitively coupled.

<Surface modification device>
The plasma generation apparatus of the present invention can perform surface modification of a printing surface on which printing is performed by an inkjet printer or the like.

  Since the plasma generation apparatus of the present invention is a pulse oscillation apparatus that can arbitrarily change electromagnetic waves (microwaves) from nanoseconds to milliseconds, various pulse oscillation patterns can be easily changed. This makes it possible to easily control the type of radical generated by changing the energy state during ionization. Further, even if the printing surface is not flat but curved, the plasma generator is mounted so that the height from the printing surface of the ink cartridge can be finely adjusted. Thus, plasma can be generated to satisfactorily modify the surface of the substrate.

<Optical analyzer>
The plasma generation apparatus of the present invention can constitute an analysis apparatus in combination with measurement means. This analysis apparatus includes the plasma generation apparatus of the present invention. A part of the analysis object is brought into a plasma state by breakdown plasma generated by the plasma generation apparatus, and the plasma light of the analysis object is collected by a condensing optical system. Light and measure by measuring means.

  The control device controls the breakdown plasma and electromagnetic wave synchronously to control the generation timing of the plasma and the emission timing of the electromagnetic wave, and the microwave emission time so that the generated plasma does not disappear in a short time. By controlling the above, the plasma maintenance time is controlled. The measurement means is a measurement means similar to the measurement system of LIBS (Laser Excitation Breakdown Spectroscopy), and includes a spectroscope that splits light emitted from plasma and an optical sensor that receives light split by the spectroscope. And is configured to perform arithmetic processing based on an electrical signal output from the optical sensor.

  This optical analyzer can be configured as a system that receives light using a fiber or the like. The received light may be a lens, fiber, or direct. When the light receiving system is made parallel by a fiber or the like, it is the same as scanning by sequentially analyzing the light received. That is, it is possible to analyze multiple points simultaneously with one analyzer. If this is introduced to a measurement system, it becomes a scanning device that analyzes not a single point but a multipoint (volumetric). This can be configured to be portable (hand carry method).

  As this application, it is possible to configure a measurement control device that analyzes a substance in front and identifies a substance or molecule, atom, temperature, pressure, etc. flowing there. For example, aluminum recycling equipment, steam, 100% inspection of car parts, semiconductor parts inspection, foreign matter inspection of postal items, etc. In addition, it can be used as a gas analyzer if attached to the back of a car / heat engine, By scanning human skin, it is possible to test for oils and viruses attached to the skin.

  In addition, the apparatus of this invention can transfer the measured data to big data with a network, and can analyze it. In the apparatus of the present invention, only measured data is accumulated, and there is no large data. This measurement data can be transferred to big data through a mobile phone or a personal computer, and can be analyzed, inferred from past similar data, and the like. Measurement data is only data such as plasma temperature and concentration, measured aluminum, cesium, etc., but this data is used to predict the next, for example, when there is a lot of cesium, a warning that it is dangerous. If it is data from fish, it can give a warning that it is not suitable for food, and analogy and alert. In the factory line, it can be used as a foreign matter detection system at the scanning in the line. Since it is a hand carry, it can be used as a handy device like a stethoscope, but it is possible to configure a system that analyzes the result using big data and performs an analogy warning.

  Fault diagnosis can also be performed. Since it is a hand-carried plasma generator, it can be used by attaching to any device. By attaching to a mobile phone, it is possible to detect the temperature of a human touching the mobile phone, the presence of dirt on the hands, and the presence of bacteria. For example, since it is known that the bacterium is O157, it is possible to determine the region where the current O157 exists by issuing an instruction to measure O157 throughout Japan. It can also be used for other disasters and virus countermeasures. Similarly, if you have it in your child, you can use it to investigate how the cold spreads about the spread of the cold.

  Car exhaust emission inspection can also be performed, and it can be seen that, for example, PM increases when driving in China using the car itself as a monitoring device. That is, the moving object itself serves as a sensor. Instead of a single piece of data, it is possible to control the current material of the entire region, society as a whole, the line in the factory, and the next phenomenon event predicted from that material. Since a control function for feedback can be obtained, the next action can be predicted. Examples include sorting by aluminum purity, medical applications, and inspection of what has flowed through the line by bringing portable devices into the factory line.

<Ignition device>
The plasma generator of the present invention can constitute an ignition device. This ignition device is a device that ignites a combustible air-fuel mixture by applying energy higher than the minimum discharge energy. Since it is not ignited if it is less than the minimum discharge energy, so-called explosion-proof measures can be taken. Appropriate ignition is possible according to the concentration, adhesion, and soot of the high-temperature / high-pressure mixture

<Drying device>
The plasma generation apparatus of the present invention can constitute a drying apparatus. This drying device is a device that radiates electromagnetic waves to moisture and evaporates by applying energy by breakdown plasma generated by the plasma generation device.

<Purification device>
The plasma generator of the present invention can constitute a purification device. This purification device is a device that radiates electromagnetic waves to impurities contained in waste or the like, and gives energy by the breakdown plasma generated by the plasma generation device to evaporate.

<Bacteria sterilization sterilizer>
The plasma generation apparatus of the present invention can constitute a sterilization sterilization apparatus. This sterilization sterilization apparatus is an apparatus that radiates electromagnetic waves to various bacteria and viruses and kills them by breakdown plasma generated by the plasma generation apparatus.

  As described above, the present invention is applied to a plasma generation device, in particular, a device for generating plasma by boosting electromagnetic waves, and by using a semiconductor material with high energy efficiency as a power device that oscillates electromagnetic waves, The present invention is applied to a plasma generating apparatus including an electromagnetic wave oscillator that is significantly smaller than a semiconductor electromagnetic wave oscillator.

3 Electromagnetic wave discharger (third example)
4 Control device 5 Electromagnetic wave discharger (first example)
9 Electromagnetic wave discharger (second example)
MW electromagnetic wave oscillator
P Electromagnetic power supply

Claims (4)

An electromagnetic wave oscillator that uses silicon carbide, gallium nitride, gallium oxide or diamond as a semiconductor material, has an energy efficiency of 70% or more, and an electromagnetic wave oscillation pattern is a pulse oscillation system;
An electromagnetic wave discharger that generates a breakdown plasma by increasing a potential difference of a discharge gap by a boosting unit including a resonance circuit that boosts an electromagnetic wave supplied from the electromagnetic wave oscillator; and
A control device for controlling electromagnetic oscillation from the electromagnetic wave oscillator in a pulse mode;
A plasma generation apparatus comprising: An electromagnetic wave oscillator that uses silicon carbide, gallium nitride, gallium oxide or diamond as a semiconductor material, has an energy efficiency of 70% or more, and an electromagnetic wave oscillation pattern is a pulse oscillation system;
An electromagnetic wave discharger that raises the potential difference of the discharge gap by a boosting means comprising a resonance circuit that boosts the electromagnetic wave supplied from the electromagnetic wave oscillator that generates the breakdown plasma, and generates a discharge. A breakdown plasma generator composed of a high voltage discharger or a laser irradiator that raises the potential difference and generates discharge;
An electromagnetic wave irradiator that irradiates the plasma generated by the breakdown plasma generator with an electromagnetic wave supplied from the electromagnetic wave oscillator;
A control device for controlling electromagnetic oscillation from the electromagnetic wave oscillator in a pulse mode;
A plasma generation apparatus comprising: A mechanism for detecting pressure and / or temperature in the breakdown plasma generation region;
The plasma generation device according to claim 2, wherein the control device maintains the plasma by changing an electromagnetic wave oscillation pattern of the electromagnetic wave irradiator in accordance with the pressure and / or temperature detected by the detection mechanism.   The plasma generating apparatus according to claim 1, wherein the electromagnetic wave oscillator is a general type.

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