JP2013251129A - Atmospheric-pressure plasma generating device and atmospheric-pressure plasma generating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an atmospheric-pressure plasma generating device capable of minimize variation of plasma energy output from plural atmospheric-pressure plasma generating devices.SOLUTION: An atmospheric-pressure plasma generating device 10 includes: a discharge tube 14 through which discharge gas flows; an antenna 16 connected to a high-frequency power source 12 to supply high-frequency power to the discharge tube 14; and a matching circuit 18 for matching impedance between the high-frequency power source 12 and the antenna 16. The matching circuit 18 includes: a first matching circuit section 18a connected in parallel to the antenna 16; and a second matching circuit section 18b connected in series to the antenna 16. The first matching circuit section 18a is configured including a coil or corrugated plate wiring member 24, 24' having inductance component and a variable capacitor 22 connected to each other in series.

Description

  The present invention relates to an atmospheric pressure plasma generation apparatus and an atmospheric pressure plasma generation method.

  2. Description of the Related Art Conventionally, an atmospheric pressure plasma generator that generates atmospheric pressure plasma from a discharge tube by supplying high-frequency power to a discharge tube through which discharge gas flows is known (see, for example, Patent Document 1). The atmospheric pressure plasma generator described in Patent Document 1 is compact (downsized), an antenna disposed in the vicinity of a discharge tube, a high-frequency power source connected to the antenna and supplying high-frequency power to the antenna, And a matching circuit for impedance matching between the high frequency power source and the antenna. The matching circuit includes a series matching circuit unit that is connected in series with the antenna and includes an inductance and a capacitance, and a parallel matching circuit unit that is connected in parallel with the antenna and includes a capacitance. The matching circuit having such a configuration appropriately matches the impedance between the high-frequency power source and the antenna, whereby high-frequency power is supplied from the high-frequency power source to the antenna with high efficiency.

JP 2009-259626 A

  By the way, the energy of plasma generated by each of a plurality of produced atmospheric pressure plasma generators varies depending on the machine difference (solid difference) of the apparatuses. For example, variations in plasma energy of a plurality of atmospheric pressure plasma generators occur due to variations in parasitic reactance of wiring and circuit resistance in a circuit through which a high-frequency current supplied from a high-frequency power source to an antenna flows.

  Therefore, an object of the present invention is to reduce the variation in plasma energy of a plurality of atmospheric pressure plasma generators.

  In order to solve the above-described problem, according to the first aspect of the present invention, a high-frequency power source that generates high-frequency power, a discharge tube through which discharge gas flows, and a high-frequency power source connected to the discharge tube are supplied with high-frequency power And a matching circuit for impedance matching between the high-frequency power source and the antenna, the matching circuit being connected in parallel to the antenna, a first matching circuit unit connected in series to the antenna Two matching circuit sections, and the first matching circuit section is configured by connecting a coiled or corrugated wiring member having an inductance component and a variable capacitor in series, and generating atmospheric pressure plasma. An apparatus is provided.

  According to the second aspect of the present invention, the atmospheric pressure plasma according to the first aspect, wherein the wiring member of the first matching circuit unit is configured by a coil wound around a core material that absorbs heat. A generator is provided.

  According to a third aspect of the present invention, there is provided the atmospheric pressure plasma generator according to the second aspect, wherein the core material is cylindrical and the coil is wound around the outer peripheral surface of the cylindrical core material. Provided.

  According to the fourth aspect of the present invention, the second matching circuit unit has a coil for adjusting the phase of the high-frequency power, and at least a part of the coil of the first matching circuit unit and the second matching circuit The atmospheric pressure plasma generator according to the second or third aspect is provided in which at least a part of the coil of the part is wound around a common core material.

  According to a fifth aspect of the present invention, there is provided an atmospheric pressure plasma generation method for generating plasma under atmospheric pressure, wherein a high frequency power source is generated in a discharge tube through which discharge gas flows via an antenna connected to the high frequency power source. Plasma is generated by supplying high-frequency power, and impedance matching between the high-frequency power source and the antenna is performed by the first matching circuit unit connected in parallel to the antenna and the second matching circuit unit connected in series to the antenna. There is provided an atmospheric pressure plasma generation method in which the first matching circuit unit is configured by connecting a coiled or corrugated wiring member having an inductance component and a variable capacitor in series.

  According to the present invention, the first matching circuit unit configured by connecting the coiled or corrugated wiring member having the inductance component and the variable capacitor connected in series with the antenna in series, It is possible to reduce variations in plasma energy output from each of a plurality of atmospheric pressure plasma generators caused by variations in wiring parasitic reactance and circuit resistance in a circuit through which high-frequency power supplied from a high-frequency power source to an antenna flows. .

1 is a circuit diagram of an atmospheric pressure plasma generator according to an embodiment of the present invention. Simplified circuit diagram of comparative example and example of atmospheric pressure plasma generator The graph which shows the relationship between the parasitic inductance and capacitance in the 1st matching circuit part of a comparative example and an Example The graph which shows the relationship between the circuit resistance in the 2nd matching circuit part of a comparative example and an Example, and the capacitance of a 1st matching circuit part Diagram showing the structure of the atmospheric pressure plasma generator The perspective view of the coil material which accommodates the core material and core material which wind a coil The figure which shows the structure of the atmospheric pressure plasma generator which concerns on another embodiment of this invention The perspective view of the supporting member which supports the core material which winds a coil, and the both ends of a core material

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a circuit diagram of an atmospheric pressure plasma generator according to an embodiment of the present invention.

  The atmospheric pressure plasma generator 10 is an apparatus for generating plasma under atmospheric pressure conditions, and as shown in FIG. 1, a high frequency power source 12 that generates high frequency power, a discharge tube 14 through which discharge gas flows, and a high frequency power source. 12, an antenna 16 for supplying high-frequency power to the discharge tube 14, and a matching circuit 18 for impedance matching between the high-frequency power source 12 and the antenna 16.

  The high frequency power source 12 generates high frequency power and supplies the generated high frequency power to an antenna 16 connected to the high frequency power source 12.

  The discharge tube 14 is a tubular member through which discharge gas flows, and generates plasma when high-frequency power is supplied from the high-frequency power source 12 via the antenna 16.

  The antenna 16 is provided in the vicinity of the discharge tube 14 and supplies high-frequency power supplied from the high-frequency power source 12 to the discharge tube 14.

  The matching circuit 18 is a circuit for impedance matching between the high-frequency power source 12 and the antenna 16, and includes a first matching circuit unit 18 a connected in parallel to the antenna 16 and a first connection connected in series to the antenna 16. 2 matching circuits 18b.

  The first matching circuit unit 18a is configured by connecting a coil 24 in series to a parallel circuit of a fixed capacitor 20 having a constant capacitance and a variable capacitor 22 having an adjustable capacitance. One terminal of the coil 24 in the first matching circuit 18 a is connected to the parallel circuit of the fixed capacitor 20 and the variable capacitor 22, and the other terminal is connected to the second matching circuit 18 b and the output terminal of the high frequency power supply 12. Electrically connected. In addition, the terminal of the fixed capacitor 20 and the terminal of the variable capacitor 22 on the opposite side to the terminal connected to the coil 24 in the first matching circuit 18a connected in parallel to the antenna 16 are electrically connected to GND. Has been.

  The second matching circuit unit 18 b is configured by connecting the coils 26 and 28 and the variable capacitor 36 in series to the antenna 16. Strictly speaking, the antenna 16 is disposed between the coil 28 and the variable capacitor 36 in the second matching circuit 18b. The terminal on the opposite side of the coil 28 connected to the coil 28 is electrically connected to the output terminal of the high frequency power supply 12. Further, the terminal on the opposite side of the variable capacitor 36 to the antenna 16 in the second matching circuit 18b is electrically connected to GND.

  In such a matching circuit 18, impedance matching between the high frequency power supply 12 and the antenna 16 is achieved by appropriately setting the inductances of the coils 24, 26, and 28 and the capacitances of the fixed capacitor 20 and the variable capacitors 22 and 36. be able to.

For example, when the capacitance of the fixed capacitor 20 is C ₂₀ , the capacitance of the variable capacitor 22 is C ₂₂ , and the inductance of the coil 24 is L ₂₄ , the impedance of the first matching circuit unit 18 a is jωL ₂₄ −1 / jω (C ₂₀ + C ₂₂ ). Further, assuming that the capacitance of the variable capacitor 36 is C ₃₆ , the inductances of the coils 26 and 28 are L ₂₆ and L ₂₈ , the inductance of the antenna 16 is L ₁₆ , and the circuit resistance is R, the impedance of the second matching circuit 18 b is R + jω (L ₁₆ + L ₂₆ + L ₂₈ ) −1 / jω (C ₃₆ ). By matching the impedance of the first matching circuit unit 18a and the impedance of the second matching circuit unit 18b, the high-frequency power output from the high-frequency power source 12 can be supplied to the antenna 16 with high efficiency.

  In addition, the coils 26 and 28 of the second matching circuit unit 18 b function as a phase adjustment unit of the matching circuit 18 that adjusts the phase of the high-frequency power (high-frequency current) in the antenna 16. Specifically, the coils 26 and 28 adjust the phase of the high frequency current so that the amplitude of the high frequency current in the antenna 16 is maximized. Thereby, the energy of the plasma generated via the antenna 16 is maximized.

  When the phase adjustment unit that maximizes the amplitude of the high-frequency current in the antenna 16 is configured by the coils 26 and 28, the phase adjustment unit can be reduced in size. For example, when the phase adjustment unit is configured by a corrugated plate-like (wavy or meandering flat plate) conducting wire, the length of the conducting wire is longer than that of the coil 26 and 28. For example, when the frequency of the high-frequency power supply 12 is 40 or 68 MHz, which is one of the ISM (Industry-Science-Medical) band bands, the length of the conducting wire of the phase adjusting unit formed of the corrugated conducting wire is 2 300 mm is required. On the other hand, the length of the conducting wire of the phase adjustment unit configured like a coil like the coils 26 and 28 can be configured to be 1,100 mm which is half or less.

  Further, by adjusting the capacitances of the variable capacitor 22 of the first matching circuit unit 18a connected in parallel to the antenna 16 and the variable capacitor 36 of the second matching circuit unit 18b connected in series to the antenna 16, Variations in impedance of the first matching circuit unit 18a and the second matching circuit unit 18b, which are causes of machine differences (individual differences) between the plurality of atmospheric pressure plasma generators 10, can be reduced. Thereby, the variation in the energy of the plasma output from each of the plurality of atmospheric pressure plasma generators 10 can be minimized.

  In particular, in the case of the atmospheric pressure plasma generator 10 according to the present embodiment, the antenna 16 of the matching circuit 18 is connected to the antenna 16 of the matching circuit 18 in case the impedance variation of the first matching circuit unit 18a or the second matching circuit unit 18b is large. On the other hand, the coil 24 is provided in the first matching circuit unit 18a connected in parallel. This will be specifically described.

The wiring of the first matching circuit portion 18a of the matching circuit 18 of the atmospheric pressure plasma generating apparatus 10, the parasitic inductance L ₀ is present. The parasitic inductance L ₀ may differ as a machine difference (solid difference) between the plurality of atmospheric pressure plasma generators 10. In addition, the circuit resistance R of the second matching circuit unit 18b may also differ as a machine difference (individual difference) between the plurality of atmospheric pressure plasma generators 10.

When the parasitic inductance L ₀ and the circuit resistance R are varied, the impedance components of the first matching circuit portions 18a of the plurality of atmospheric pressure plasma generators 10 are varied. As a result, the atmospheric pressure plasma is generated. The plasma energy output from the apparatus 10 varies. As a countermeasure, a coil 24 is provided in the first matching circuit unit 18a.

  The effect of providing the coil 24 in the first matching circuit section 18a will be specifically described with reference to FIG. The circuit shown in FIG. 2 is a simplified version of the circuit shown in FIG.

  FIG. 2A shows a circuit of the atmospheric pressure plasma generator 10 of the comparative example. On the other hand, FIG.2 (b) has shown the circuit of the atmospheric pressure plasma generator 10 of an Example. The comparative example is different from the embodiment in that the first matching circuit portion 18a does not include the coil 24.

First, the parasitic inductance L ₀ of the wiring of the first matching circuit portion 18a of a plurality of atmospheric pressure plasma generator 10, given as an example the case where different within the 18～22NH (variations occur). Note that the frequency of the high frequency power supply 12 is 40.68 MHz, and the target value of the reactance component of the first matching circuit unit 18a (the value necessary for matching the impedance between the high frequency power supply 12 and the antenna 16) is -5.025Ω. In this case, the circuit resistance R of the second matching circuit unit 18b is 0.5Ω. Further, the inductance _{L 24} of the coil 24 of the embodiment and 27NH.

For comparative example shown in FIG. 2 (a), the parasitic inductance L ₀ of the wiring of the first matching circuit portion 18a are different in the range of 18～22NH, as shown in FIG. 3, the first matching circuit portion The capacitance C of 18a (the sum of the capacities of the fixed capacitor 20 and the variable capacitor C ₂₀ + C ₂₂ ) needs to change within a range of 406 to 367 pF. That is, as the variable capacitor 22, it is necessary to employ a variable capacitor whose capacitance adjustment amount is at least 39 pF.

On the other hand, in the embodiment shown in FIG. 2 (b), that is, when the inductance _{L 24} to the first matching circuit portion 18a is provided with a coil 24 of 27NH, parasitic inductance _L of wiring of the first matching circuit portion 18a ₀ Is different within the range of 18 to 22 nH, as shown in FIG. 3, the capacitance C of the first matching circuit section 18a (the sum of the capacitances of the fixed capacitor 20 and the variable capacitor 22 C ₂₀ + C ₂₂ ) is 238 to 223 pF. It is necessary to change within the range. That is, the variable capacitor 22 can be dealt with by adopting a variable capacitor having a capacitance adjustment amount of at least 15 pF, for example, a variable capacitor having a capacitance range of 2 to 20 pF.

As can be seen from this comparative example and the example, if the variation in the parasitic inductance L ₀ of the first matching circuit portion 18a having a variable capacitor 22 occurs, the coil 24 is provided in the first matching circuit portion 18a In the case of the embodiment, the amount of adjustment of the capacity of the variable capacitor 22 can be further reduced.

From another viewpoint, when the amount of adjustment of the capacitance of the variable capacitor of the embodiment and the variable capacitor of the comparative example is the same, the embodiment has a parasitic inductance L of the first matching circuit unit 18a as compared with the comparative example. _It can be seen that a smaller variable capacitor 22 can effectively cope with a large variation of _zero .

That is, in the matching circuit 18 that performs impedance matching between the high-frequency power source 12 and the antenna 16, the first matching circuit unit 18a configured by connecting the variable capacitor 22 and the coil 24 in series is configured only by the variable capacitor. that in comparison with the first matching circuit portion, caused by the variation of the parasitic Riakudansu L ₀ of the wiring of the first matching circuit portion 18a, reducing the energy variation of the plasma output from a plurality of atmospheric pressure plasma generating apparatus 10, respectively Can be made smaller. This can be handled by a small variable capacitor 22 having a small capacitance adjustment amount.

Next, the case where the circuit resistance R of the 2nd matching circuit part 18b of the some atmospheric pressure plasma generator 10 differs in the range of 0.4-0.6 (ohm) is mentioned as an example. Note that the frequency of the high frequency power supply 12 is 40.68 MHz, and the target value of the reactance component of the first matching circuit unit 18a (the value necessary for matching the impedance between the high frequency power supply 12 and the antenna 16) is -5.025Ω. a is, the parasitic inductance _{L 0} of the wiring of the first matching circuit portion 18a, for example, to 20 nH. Further, the inductance L ₂₄ of the coil 24 of the embodiment is set to 27 nH.

In the case of the comparative example shown in FIG. 2A, if the circuit resistance R of the second matching circuit section 18b is different within the range of 0.4 to 0.6Ω, as shown in FIG. The capacitance C of the unit 18a (the sum of the capacitances of the fixed capacitor 20 and the variable capacitor 22 C ₂₀ + C ₂₂ ) needs to change within a range of 407 to 368 pF. That is, as the variable capacitor 22, it is necessary to employ a variable capacitor whose capacitance adjustment amount is at least 39 pF.

On the other hand, in the embodiment shown in FIG. 2 (b), that is, when the inductance _{L 24} is a coil 24 of 27nH provided in the first matching circuit portion 18a, the circuit resistance R of the second matching circuit portion 18b is 0. When the difference is within the range of 4 to 0.6Ω, as shown in FIG. 4, the capacitance C of the first matching circuit unit 18a (the sum of the capacitances of the fixed capacitor 20 and the variable capacitor 22 C ₂₀ + C ₂₂ ) is 237 to It needs to change within a range of 223 pF. That is, the variable capacitor 22 can be dealt with by adopting a variable capacitor having a capacitance adjustment amount of at least 14 pF, for example, a variable capacitor having a capacitance range of 2 to 20 pF.

  As can be seen from the comparative example and the embodiment, when the circuit resistance R of the second matching circuit section 18b varies, the coil 24 is provided in the first matching circuit section 18a (in the case of the embodiment). ), The amount of adjustment of the capacitance of the variable capacitor 22 can be reduced.

  From another viewpoint, when the amount of adjustment of the capacitance of the variable capacitor of the embodiment and the variable capacitor of the comparative example is the same, the embodiment has a circuit resistance R of the second matching circuit unit 18b as compared with the comparative example. It can be seen that a smaller variable capacitor 22 can effectively cope with a large variation in the above.

  That is, in the matching circuit 18 that performs impedance matching between the high-frequency power source 12 and the antenna 16, the variable capacitor 22 and the coil 24 are connected in series, and the first matching circuit is connected in parallel to the antenna 16. The unit 18a is composed of only a variable capacitor, and the circuit of the second matching circuit unit 18b connected in series to the antenna 16 as compared to the first matching circuit unit connected in parallel to the antenna 16. It is possible to reduce the variation in the energy of the plasma output from each of the plurality of atmospheric pressure plasma generators 10 caused by the variation in the resistance R and to make it smaller.

  Next, the structure of the atmospheric pressure plasma generator 10 of this Embodiment is demonstrated. FIG. 5 is a structural diagram of the atmospheric pressure plasma generator 10 corresponding to the circuit shown in FIG.

  FIG. 5 shows the atmospheric pressure plasma generator 10 with a housing cover (not shown) removed. As shown in FIG. 5, the discharge tube 14, the antenna 16, the fixed capacitor 20, the variable capacitors 22 and 36, and the coils 24, 26 and 28, which are components of the atmospheric pressure plasma generator 10, are base members. 40. For example, when the atmospheric pressure plasma generator 10 is mounted on a head (not shown) that moves relative to the plasma-treated substrate, the base member 40 functions as a bracket.

  The antenna 16, the fixed capacitor 20 and the variable capacitor 22 of the first matching circuit unit 18a, and the variable capacitor 36 of the second matching circuit unit 18b are provided on an insulating substrate 42 attached to the base member 40. ing.

  The antenna 16 is configured by a part of a conductor 44 that is provided on the substrate 42 and electrically connects the coil 28 of the second matching circuit unit 18 b and the variable capacitor 36. The antenna 16 is formed as a corrugated electrode (a corrugated or serpentine flat plate). One terminal of each of the fixed capacitor 20 and the variable capacitor 22 of the first matching circuit section 18a and the variable capacitor 36 of the second matching circuit section 18b is provided on a substrate 42 and is a conductor 46 connected to GND. Is electrically connected. The other terminals of the fixed capacitor 20 and the variable capacitor 22 in the first matching circuit unit 18 a are electrically connected to the coil 24 through a conductor 48. A part of the other terminal of the variable capacitor 36 of the second matching circuit section is connected to the conductor 44 constituting the antenna 16. Specifically, the other terminal of the variable capacitor 36 is connected to one end of the conductor 44 to which the coil 28 is connected and the other end on the opposite side across the antenna 16. The second matching circuit unit 18b includes one variable capacitor 36 as a capacitance, but may be configured by a combination of a variable capacitor and a fixed capacitor.

  The board | substrate 42 with which the some conductors 44-48 were provided is produced from insulating materials (dielectric material), such as ceramics provided with high heat absorption (heat dissipation). During operation of the atmospheric pressure plasma generator 10, heat generated in the conductors 44 to 48 is absorbed by the substrate 42. The heat absorbed by the substrate 42 is radiated to the outside air indirectly or directly through the base member 40. Thereby, a change in electrical characteristics such as resistance and inductance of the conductors 44 to 48 caused by heat can be suppressed. As a result, impedance matching between the high frequency power supply 12 and the antenna 16 is maintained, and the atmospheric pressure plasma generator 10 can generate stable plasma.

  The coil 24 of the first matching circuit unit 18 a and the coils 26 and 28 of the second matching circuit unit 18 b are wound around insulating core members 56 and 58. Specifically, as shown in FIG. 6, the core members 56 and 58 are provided with spiral grooves 56 a and 58 a on the outer peripheral surface for accommodating the conductive wires of the coil.

  The coil 24 of the first matching circuit unit 18 a connected in parallel to the antenna 16 and the coil 26 of the second matching circuit unit 18 b connected in series to the antenna 16 are wound around a common core material 56. . Thereby, the number of core materials for coil winding is reduced. Further, the coil 24 of the first matching circuit unit 18a and the coil 26 of the second matching circuit unit 18b can be configured integrally (one coil shape). That is, the coil 24 of the first matching circuit unit 18a is constituted by a part of one coil wound around the core material 56, and the coil 26 of the second matching circuit unit 18b is constituted by the remaining part. It becomes possible. For this purpose, as shown in FIG. 1, an apparently one coil formed in the form of one coil is replaced with a coil 24 of the first matching circuit unit 18a and a coil 26 of the second matching circuit unit 18b. A conductive wire 62 electrically connected to the high-frequency power source 12 via the connector end 60 is connected to a portion of one coil wound around the core member 56 that can be electrically divided into two. .

  A core material 56 around which the coil 24 of the first matching circuit portion 18a and the coil 26 of the second matching circuit portion 18b are wound, and a core material 58 around which the coil 28 of the second matching circuit portion 18b is wound. Is provided in the base member 40 in a state of being accommodated in the coil case 64. The coil case 64 includes two recesses 64a for accommodating a core material 56 around which the coils 24 and 26 are wound and a core material 58 around which the coil 28 is wound. Each of the recesses 64a has a groove shape extending in parallel with each other, and includes a cylindrical inner surface that contacts the outer peripheral surfaces of the core members 56 and 58.

  In addition, when the core members 56 and 58 are accommodated in the concave portions 64a of the coil case 64, the winding directions of the coils 24 and 26 and the winding direction of the coil 28 are opposite to each other. 28 is wound around corresponding core members 56 and 58. Thereby, the magnetic field generated from the coils 24 and 26 and the magnetic field generated from the coil 28 cancel each other, and the change in inductance of the coils 24, 26 and 28 caused by the magnetic field can be suppressed.

  The core members 56, 58 around which the coils 24, 26, 28 are wound, and the coil case 64 that accommodates the core members 56, 58 are preferably configured to absorb the heat of the coils 24, 26, 28. For example, the core members 56 and 58 are made of a tubular member and include hollow portions 56b and 58b communicating with the outside air as shown in FIGS. The core members 56 and 58 and the coil case 64 are made of an insulating material having high heat absorption (heat dissipation) such as ceramics. As a result, the heat generated in the coils 24, 26, 28 during the operation of the atmospheric pressure plasma generator 10 is absorbed by the core members 56, 58 and the coil case 64. The heat absorbed by the core members 56, 58 is radiated to the outside air or transmitted to the coil case 64 through the surfaces of the core members 56, 58 and the hollow portions 56 b, 58 b of the core members 56, 58. The heat of the coil case 64 is radiated to the outside through the base member 40 or directly. As a result, changes in electrical characteristics such as inductance of the coils 24, 26, and 28 caused by heat can be suppressed. Thereby, impedance matching between the high frequency power supply 12 and the antenna 16 is maintained, and the atmospheric pressure plasma generator 10 can generate stable plasma.

  The core members 56 and 58 are provided with hollow portions 56a and 56b. However, the core members 56 and 58 are solid if there is no particular problem with respect to the electrical characteristics such as heat dissipation and impedance of the coils 24, 26 and 28. May be.

  Further, in order to cool the substrate 42 that has absorbed heat from the conductors 44 to 48, the core materials 56 and 58 that have absorbed heat from the coils 24 to 28, the coil case 64, and the like, the substrate 42, the core materials 56 and 58, and the coil case are also used. An air blower (not shown) such as a fan that forcibly moves the air around 64 may be provided in the atmospheric pressure plasma generator 10.

  Moreover, you may cover the coils 24-28 whole with the member provided with high heat absorption. For example, as shown in FIG. 6, a ceramic cover member that covers the portions of the core members 56 and 58 around which the coils 24, 26, and 28 are wound, which is not accommodated in the recess 64 a of the coil case 64. (Not shown) may be provided. Alternatively, for example, core members 56 and 58 around which the coils 24, 26, and 28 are wound may be inserted into a ceramic block (not shown) in which two through holes are formed. Thereby, the change of electrical characteristics, such as the inductance of the coils 24, 26, and 28, caused by heat can be further suppressed.

  Similarly, a ceramic cover member (not shown) may be provided that covers at least a portion of the conductor 44 on the substrate 42, particularly the antenna 16, that is, includes them in cooperation with the substrate 42. Thereby, a change in electrical characteristics such as resistance and inductance of the conductor 44 caused by heat can be suppressed.

  According to the present embodiment, the first matching circuit unit 18 a configured by connecting the variable capacitor 22 and the coil 24 connected in parallel to the antenna 16 in series allows the antenna 16 to be connected to the antenna 16. It is possible to minimize the variation in the plasma energy output from each of the plurality of atmospheric pressure plasma generators 10 caused by variations in the parasitic reactance and circuit resistance of the wiring in the circuit through which the high-frequency power supplied to the circuit flows.

  Although the present invention has been described with reference to the above-described embodiment, the present invention is not limited to the above-described embodiment.

  For example, in the case of the atmospheric pressure plasma generator 10 of the above-described embodiment, as shown in FIG. 1, the capacitance component of the impedance of the first matching circuit unit 18 a of the matching circuit 18 is the fixed capacitor 20 and the variable capacitor 22. Although provided by the parallel circuit, the present invention is not limited to this. The capacitance component of the first matching circuit unit 18a may be given only by the variable capacitor 22.

  In the case of the atmospheric pressure plasma generation apparatus 10 of the above-described embodiment, the coil 24 of the first matching circuit unit 18a and the coils 26 and 28 of the second matching circuit unit 18b are cylindrical as shown in FIG. However, the present invention is not limited to this. The core material according to the present invention may be any shape as long as the coils 24, 26, and 28 can be wound, and may be, for example, a cylindrical shape, a U shape, a C shape, an uneven shape, or the like.

  Furthermore, in the case of the atmospheric pressure plasma generator 10 of the above-described embodiment, as shown in FIG. 1, the first matching circuit unit 18a of the matching circuit 18 includes the coil 24, but the present invention is not limited to this. Any wiring member that can give an inductance component to the impedance of the first matching circuit portion 18a may be used.

  FIG. 7 shows the structure of an atmospheric pressure plasma generator according to another embodiment of the present invention.

  The atmospheric pressure plasma generator 10 'shown in FIG. 7 is the same as the atmospheric pressure plasma generator 10 shown in FIG. 5 in terms of electrical circuit, but is structurally different. In FIG. 7, the constituent elements having the apostrophe attached to the reference numerals are electrically the same as the constituent elements shown in FIG. 5 attached with the same reference numerals, but mechanically (shape and structure). Is different.

  The inductance component of the impedance of the first matching circuit section 18a is provided by the coil 24 in the case of the atmospheric pressure plasma generator 10 shown in FIG. 5, whereas the atmospheric pressure plasma generator 10 ′ shown in FIG. In some cases, it is provided by a corrugated (corrugated flat plate) conductor 24 '.

  For example, when the frequency of the high-frequency power source 12 that supplies high-frequency power to the antenna 16 is a relatively low frequency such as 40.68 MHz, the wiring member that provides an inductance component to the impedance of the first matching circuit unit 18a is relatively Need to be long. In this case, like the coil 24 shown in FIG. 5, the wiring member which gives an inductance component to the impedance of the first matching circuit portion 18a is preferably coiled in order to avoid an increase in the size of the atmospheric pressure plasma generator.

  On the other hand, when the frequency of the high-frequency power source 12 is a relatively high frequency such as 160 MHz, the wiring member that gives an inductance component to the impedance of the first matching circuit unit 18a is compared to the case where the frequency of the high-frequency power source 12 is a low frequency. May be relatively short. In this case, as shown in FIG. 7, the wiring member that gives an inductance component to the impedance of the first matching circuit portion 18 a may be corrugated (a wavy or meandering flat plate).

  Thus, in the present invention, as long as the wiring member can give an inductance component to the impedance of the first matching circuit portion 18a, the shape of the wiring member may be either a coil shape or a corrugated plate shape. .

  Furthermore, in the case of the atmospheric pressure plasma generator 10 of the above-described embodiment, as shown in FIGS. 1 and 5, the second matching circuit portion 18b of the matching circuit 18 has two coils 26 and 28, The coil 24 of the first matching circuit unit 18 a connected in parallel to the antenna 16 and the coil 26 of the second matching circuit unit 18 b connected in series to the antenna 16 are wound around a common core member 56. However, the present invention is not limited to this. This is merely an example for reducing the size of the atmospheric pressure plasma generator 10.

  Specifically, in the case of the above-described embodiment, in order to reduce the size of the atmospheric pressure plasma generator 10, the total length of the conductive wires of the two coils 26 and 28 of the second matching circuit unit 18b is a high-frequency power source. The coils 26 and 28 are fabricated so that the length of the lead wire is necessary for adjusting the phase of the high-frequency current supplied from 12 to the antenna 16. The two coils 26 and 28 of the second matching circuit unit 18 b are wound around the separate core members 56 and 58, and the coil 24 of the first matching circuit unit 18 a is wound around the core member 56.

  When the frequency of the high-frequency electric current used by the atmospheric pressure plasma generator 10 is different, the length of the coil of the second matching circuit unit 18b necessary for phase adjustment of the high-frequency current is also different. Therefore, in order to reduce the size of the atmospheric pressure plasma generator 10, for example, the second matching circuit unit 18b may have three or more coils, and each of the coils may be wound around different core materials. . Further, for example, the second matching circuit unit 18b may have one coil and the coil may be wound around one core material. Similarly, the first matching circuit unit 18a may have a plurality of coils, and the coils may be wound around different core materials. Furthermore, for example, the coil of the first matching circuit unit 18a and the coil of the second matching circuit unit 18b may all be wound around one core material.

  Therefore, the present invention can adjust the phase of the high-frequency current supplied to the antenna 16 and can reduce the size of the atmospheric pressure plasma apparatus 10. The coils of the first matching circuit unit 18 a and the second matching circuit unit 18 b can be reduced in size. All combinations of numbers and cores are included.

  In addition, in the atmospheric pressure plasma generator 10 shown in FIG. 5, the core members 56, 58 around which the coils 24, 26, 28 are wound as shown in FIG. 6 are accommodated in the groove-like recess 64 a of the coil case 64. However, the present invention is not limited to this.

  If the change in electrical characteristics such as the inductance of the coils 24, 26, and 28 caused by heat is relatively small, for example, as shown in FIG. It may be supported by 66b. The support members 66 a and 66 b are provided on the base member 40 and are configured to support the core members 56 and 58 in a state of being separated from the base member 40. The support members 66a and 66b are preferably made of an insulating material such as ceramics having high heat absorption (heat dissipation), like the core materials 56 and 58 and the substrate 42 (see FIG. 5).

  Thus, if it can support the core materials 56 and 58 around which the coils 24, 26, and 28 are wound, the core material is more preferably excellent in heat absorption (heat dissipation). The support method of 56 and 58 and the form of a support member are not ask | required.

  The present invention is applicable to any apparatus that performs plasma processing under atmospheric pressure.

DESCRIPTION OF SYMBOLS 10 Atmospheric pressure plasma generator 12 High frequency power supply 14 Discharge tube 16 Antenna 18 Matching circuit 18a 1st matching circuit part 18b 2nd matching circuit part 22 Variable capacitor 24 Wiring member (coil)

Claims (5)

A high frequency power source for generating high frequency power;
A discharge tube through which discharge gas flows;
An antenna connected to a high frequency power supply and supplying high frequency power to the discharge tube;
A matching circuit for impedance matching between the high-frequency power source and the antenna;
Matching circuit
A first matching circuit connected in parallel to the antenna;
A second matching circuit unit connected in series to the antenna,
The atmospheric pressure plasma generator, wherein the first matching circuit unit is configured by connecting a coiled or corrugated wiring member having an inductance component and a variable capacitor in series.   The atmospheric pressure plasma generator according to claim 1, wherein the wiring member of the first matching circuit unit is configured by a coil wound around a core material that absorbs heat. The core is cylindrical,
The atmospheric pressure plasma generator according to claim 2, wherein the coil is wound around the outer peripheral surface of the cylindrical core member. The second matching circuit section has a coil for adjusting the phase of the high-frequency power;
The atmospheric pressure plasma generation according to claim 2 or 3, wherein at least a part of the coil of the first matching circuit unit and at least a part of the coil of the second matching circuit unit are wound around a common core member. apparatus. An atmospheric pressure plasma generation method for generating plasma under atmospheric pressure,
Plasma is generated by supplying high-frequency power generated by the high-frequency power source to a discharge tube through which discharge gas flows through an antenna connected to the high-frequency power source,
The high frequency power supply and the antenna are impedance-matched by the first matching circuit unit connected in parallel to the antenna and the second matching circuit unit connected in series to the antenna,
A method for generating atmospheric pressure plasma, wherein the first matching circuit unit is configured by connecting a coiled or corrugated wiring member having an inductance component and a variable capacitor in series.

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