ELECTRODE ARRANGEMENT AND PLASMA SOURCE FOR GENERATING A NON-THERMAL PLASMA, AS WELL AS METHOD FOR OPERATING A PLASMA SOURCE

Abstract

The invention relates to an electrode arrangement for generating a non-thermal plasma, with: a first electrode and a second electrode, wherein the first electrode and the second electrode are electrically insulated from each other and spaced from each other by a dielectric element, characterized in that the second electrode has an Electroless Nickel Immersion Gold (ENIG) coating, or an Electroless Nickel Electroless Palladium Immersion Gold (ENEPIG) coating, or an Electroless Nickel Immersion Palladium Immersion Gold (ENIPIG) coating, or an Electroless Palladium (EP) coating, or an Electroless Palladium Immersion Gold (EPIG) coating, and/or the dielectric element is made of a woven glass reinforced hydrocarbon ceramic.

Claims

1. An electrode arrangement for generating a non-thermal plasma, comprising: a first electrode and a second electrode, wherein the first electrode and the second electrode are electrically insulated from each other and spaced from each other by a dielectric element, characterized in that: the second electrode comprises an Electroless Nickel Immersion Gold (ENIG) coating, an Electroless Nickel Electroless Palladium Immersion Gold (ENEPIG) coating, an Electroless Nickel Immersion Palladium Immersion Gold (ENIPIG) coating, an Electroless Palladium (EP) coating, or an Electroless Palladium Immersion Gold (EPIG) coating, or the dielectric element comprises a woven glass reinforced hydrocarbon ceramic.

2. The electrode arrangement according to claim 1, characterized in that: the first electrode, viewed in a direction towards the second electrode, comprises a thickness of at least 10 μm to at most 50 μm, preferably 35 μm, or the second electrode, viewed in a direction towards the first electrode, comprises a thickness of at least 10 μm to at most 50 μm or the dielectric element comprises a thickness of at least 100 μm to at most 300 μm or the second electrode comprises at least one electrode segment comprising a length of 4 to 30 cm, wherein two or more electrode segments are arranged in parallel or near-parallel, and/or the ENIG, or ENEPIG, or ENIPIG or EP or EPIG coating of the second electrode has a thickness of at least 0.3 to at most 10 μm or the second electrode has two or more electrode segments which are movable relative to each other, and/or the second electrode is flexible, so that the second electrode is adaptable to a shape of a surface in contact with the second electrode.

3. The electrode arrangement according to claim 1, characterized in that a dielectric cover element is arranged on a side of the second electrode facing away from the dielectric element, wherein the cover element, viewed in the stacking direction of the electrode, comprises a thickness of at least 0.2 μm to at most 30 μm.

4. The electrode arrangement according to claim 1, characterized in that a dielectric base element is arranged on a side of the first electrode facing away from the dielectric element.

5. The electrode arrangement according to claim 1, characterized in that at least one electrode, selected from the first electrode and the second electrode, comprises a material or consists of a material that is selected from a group consisting of copper, silver, gold and aluminium.

6. The electrode arrangement according to claim 1, characterized in that at least one element, selected from the dielectric cover element and the dielectric base element, comprises a material or consists of a material that is selected from a group consisting of silicon nitride, a silicate, in particular quartz, a glass, and a plastic.

7. The electrode arrangement according to claim 1, characterized in that the first electrode is designed flat, or the second electrode is designed structured.

8. The electrode arrangement according to claim 1, characterized in that the second electrode comprises a comb-like structure, a linear structure with at least one imaginary line, a winding structure, a spiral structure, a meandering structure, or a flat structure with at least one recess.

9. A plasma source for generating a non-thermal plasma, comprising a voltage source and an electrode arrangement according to claim 1, wherein the voltage source is electrically connected at least to the first electrode.

10. The plasma source according to claim 9, characterized in that the voltage source is adapted to apply an AC voltage to the first electrode, wherein the second electrode is preferably earthed or grounded.

11. The plasma source according to claim 9, characterized in that the plasma source is configured to generate AC voltage with an amplitude of at least 0.5 kVpp to at most 5 kVpp, or at a frequency of at least 10 kHz to at most 100 kHz.

12. The plasma source according to claim 9, characterized in that the plasma source comprises a piezoamplifier as the voltage source or electrically arranged between and in electrical contact with the voltage source and the first electrode for amplifying an AC voltage applied to the first electrode.

13. The plasma source according to claim 9, characterized in that the plasma source has a tesla coil or a resonant transformer or a resonant transformer in combination with a coil transformer as the voltage source or electrically arranged between and in electrical contact with the voltage source and the first electrode for amplifying an AC voltage applied to the first electrode.

14. The plasma source according to claim 9, characterized in that the voltage source is configured to provide an electrical power of at least 0.1 watt to at most 1 watt per cm length of the electrode assembly.

15. A method for removing of undesirable or harmful substances associated with a material to be treated, wherein an electrical voltage is applied to an electrode arrangement according to claim 1 by means of a voltage source.

16. The method according to claim 15, characterized in that the plasma source is operated with an alternating current (AC) voltage comprising an amplitude of at least 0.5 kvpp to at most 5 kvpp, or at a frequency of at least 10 khz to at most 100 khz.

17. The electrode arrangement according to claim 1, characterized in that the second electrode comprises a plurality of straight line elements arranged parallel to one another and electrically connected to one another.

18. The electrode arrangement according to claim 1, characterized in that the first electrode comprises a sheet-like structure.

19. The electrode arrangement according to claim 2, wherein the dielectric element comprises a thickness of at least 100 μm to at most 300 μm.

20. The plasma source according to claim 9, characterized in that the plasma source is configured to generate AC voltage with an amplitude of at least 1.5 kVpp to at most 4 kVpp.

Description

[0116] The invention will be further explained below with reference to the drawing. In the drawing:

[0117] FIG. 1 shows a schematic representation of an exemplary embodiment of a plasma source;

[0118] FIG. 2 shows a plurality of different exemplary embodiments of an electrode arrangement with respect to a structure of the second electrode;

[0119] FIG. 3 shows an image of an electrode arrangement according to the invention;

[0120] FIG. 4 shows an image of the electrode arrangement according to FIG. 3 after 18 hours of plasma operation, and

[0121] FIG. 5 shows an image of an electrode arrangement according to FIG. 3 or 4 without plasma operation.

[0122] FIG. 1 shows a schematic representation of an exemplary embodiment of a plasma source 1 that is configured to generate a non-thermal plasma. The plasma source 1 has a voltage source 3 that is electrically connected to an electrode arrangement 5. For its part, the electrode arrangement 5 is configured to generate a non-thermal plasma.

[0123] The electrode arrangement 5 has a first electrode 7 and a second electrode 9, wherein between the first electrode 7 and the second electrode 9, a dielectric element 11 is arranged so that the two electrodes 7, 9 are electrically insulated from each other and spaced from each other by the dielectric element 11. The two electrodes 7, 9 and the dielectric element 11 form a stack, wherein viewed in the stacking direction, the dielectric element 11 is arranged on the first electrode 7, and the second electrode 9 is arranged on the dielectric element 11.

[0124] Viewed in the stacking direction, the first electrode 7 has preferably a first thickness d1 of at least 10 μm, wherein the second electrode 9, also viewed in the stacking direction, has preferably a second thickness d2 of at least 10 to at most 50 μm. Viewed in the stacking direction, the dielectric element 11 has a third thickness d3 of at least 100 μm to at most 300 μm.

[0125] The second electrode 9 has an Electroless Nickel Immersion Gold (ENIG) coating 10, or an Electroless Nickel Electroless Palladium Immersion Gold (ENEPIG) coating 10, or an Electroless Nickel Immersion Palladium Immersion Gold (ENIPIG) coating 10, or an Electroless Palladium (EP) coating 10, or an Electroless Palladium Immersion Gold (EPIG) coating 10, and/or the dielectric element 11 is made of a woven glass reinforced hydrocarbon ceramic.

[0126] The electrode arrangement 5 is accordingly designed as a thin layer electrode arrangement and has a very slight thickness overall. This renders it pliable overall so that it can be flexibly adapted to a plurality of different uses, and in particular to a plurality of geometrically different surfaces to be treated. Moreover, the electrode arrangement 5 can be operated at a low voltage, in particular at less than 5 kVpp, due to its very thin design which increases the electrical safety of the plasma source 1.

[0127] The first electrode 7 has an Electroless Nickel Immersion Gold (ENIG) coating 8, or an Electroless Nickel Electroless Palladium Immersion Gold (ENEPIG) coating 8, or an Electroless Nickel Immersion Palladium Immersion Gold (ENIPIG) coating 8, or an Electroless Palladium (EP) coating 8, or an Electroless Palladium Immersion Gold (EPIG) coating 8.

[0128] The second electrode 9 has a dielectric cover element 13 on a side facing away from the dielectric element 11 that has a fourth thickness d4 of at least 0.1 μm to at most 30 μm viewed in the stacking direction.

[0129] The dielectric cover element 13 is preferably designed as a coating, wherein in particular the second electrode 9 is coated with the dielectric cover element 13, or with the material of the dielectric cover element 13. The dielectric cover element 13 thereby covers the second electrode 9 preferably completely.

[0130] The first electrode 7 has a dielectric base element 15 on the side facing away from the dielectric element 11. This is advantageously designed flat and extends along an overall extension of the first electrode 7 and therefore entirely covers it, at the bottom in FIG. 1. Consequently, the dielectric base element 15 very efficiently prevents coronal discharges that could otherwise proceed from the first electrode 7 so that the efficiency of the electrode arrangement 5 is increased by the electric base element 15. A fifth thickness d5 of the dielectric base element 15 is preferably selected so that on the one hand coronal discharges emitted by the first electrode 7 are reliably avoided, wherein on the other hand, the electrode arrangement 5 is designed pliable overall.

[0131] Overall, a stacked electrode arrangement 5 results with the following stack sequence: On the dielectric base element 15, the first electrode 7 is arranged on which the dielectric element 11 is arranged. The second electrode 9, on which the dielectric cover element 13 is arranged, is arranged thereupon.

[0132] The at least one first electrode 7 and/or the at least one second electrode 9 preferably has/have a material that is selected from a group consisting of copper, silver, gold and aluminum. Preferably, at least one of the first and second electrodes 7, 9 consist of the aforementioned materials.

[0133] Other conductive materials are possible for the electrodes 7, 9, in particular alloys as well, particularly preferably based on at least one of the aforementioned elements.

[0134] The dielectric cover element 13 and/or the dielectric base element 15 preferably has/have a material that is selected from the group consisting of silicon nitride, a silicate, in particular quartz, a glass, and a plastic, in particular polyamide. It is also possible for at least one of the aforementioned elements to consist of one of the aforementioned materials. Other inorganic or organic materials are also possible for the aforementioned elements as long as they have dielectric and in particular electrically insulating properties.

[0135] The first electrode 7 is preferably designed flat, in particular as a layer or leaf electrode.

[0136] The second electrode 9 is preferably designed structured. In particular, in the exemplary embodiment shown in FIG. 1, it has a plurality of linear partial electrodes 17. The structure of the second electrode 9 can in particular be tailored to a specifically designed use of the electrode arrangement 5.

[0137] The voltage source 3 is in particular electrically connected to the first electrode 7, wherein an AC voltage can be applied to the first electrode 7. The second electrode 9 is preferably earthed or grounded. In the exemplary embodiment described here, both electrodes 7, 9 are electrically connected by an amplifier 19 to the voltage source 3. The amplifier 19 is preferably designed as a piezoamplifier.

[0138] The electrode arrangement 5 is preferably operated with an AC voltage with an amplitude that is at least 0.5 kVpp to at most 5 kVpp, preferably from at least 1 kVpp to at most 4.5 kVpp, preferably from at least 1.5 kVpp to at most 4 kVpp. The AC voltage preferably has a frequency of at least 10 kHz to at most 100 kHz, preferably from at least 20 kHz to at most 80 kHz, preferably from at least 30 kHz to at most 60 kHz, preferably from at least 40 kHz to at most 50 kHz, preferably 50 kHz.

[0139] FIG. 2 shows a plurality of different exemplary embodiments of the electrode arrangement 5, wherein the first flat electrode 7 and the structured second electrode 9 are schematically portrayed in a plan view. Furthermore, the second electrode 9 shown in FIG. 2a) to FIG. 2f) have all an Electroless Nickel Immersion Gold (ENIG) coating 10, or an Electroless Nickel Electroless Palladium Immersion Gold (ENEPIG) coating 10, or an Electroless Nickel Immersion Palladium Immersion Gold (ENIPIG) coating 10, or an Electroless Palladium (EP) coating 10, or an Electroless Palladium Immersion Gold (EPIG) coating 10.

[0140] A second electrode 9 is portrayed in FIG. 2a) that has a comb-like structure with a plurality of straight lines that are arranged parallel to each other, are electrically connected to each other, and extend to the right proceeding from common backbone element 21 in FIG. 2a).

[0141] In FIG. 2b), the second electrode 9 also has a comb-like structure, wherein serpentine partial electrodes extend parallel to each other proceeding from the common backbone element 21. The individual partial electrodes are electrically connected to each other by the common backbone element 21.

[0142] In FIG. 2c), the second electrode 9 also has a linear structure, however in the form of a path running as an angular zigzag line.

[0143] In FIG. 2d), the second electrode 9 has the shape of an angular spiral.

[0144] In FIG. 2e), the second electrode 9 has the shape of a round spiral, in particular a circular spiral. Finally, the second electrode 9 in FIG. 2f) has a meandering structure.

[0145] Furthermore, the invention is explained by the following experimental tests:

[0146] FIG. 3 shows an image of an electrode arrangement 5 according to the invention, in particular the initial plasma emission at the start of a long term test. The second electrode 9 is formed as a straight line and consists of copper and has, viewed in the stacking direction, a thickness of 35 μm. Furthermore the second electrode 9 has an ENIG coating 10 with a thickness of the nickel layer of at least 3 to at most 6 μm and a thickness of the gold layer of at least 0.05 μm to at most 0.1 μm. The dielectric element 11 consists of Rogers 4350B and has a thickness of 254 μm.

[0147] FIG. 4 shows an image of the electrode arrangement 5 according to FIG. 3 after 18 hours of plasma operation.

[0148] FIG. 5 shows an image of an electrode arrangement 5 according to FIG. 3 or 4 without plasma operation. Only minor signs of change in appearance are visible, which do not affect the operability of the electrode arrangement 5. For typical odor removal applications of 1 minute each, the electrode arrangement 5 remains in good conditions even after more than 1000 applications or at least 3 years of use.