Plasma generator

Patent metadata

Field	Value
Publication number	US-10904995-B2
Application number	US-201816494261-A
Country	US
Kind code	B2
Filing date	Mar 14, 2018
Priority date	Mar 14, 2017
Publication date	Jan 26, 2021
Grant date	Jan 26, 2021

Abstract

A plasma generator is disclosed. In an embodiment a plasma generator includes a piezoelectric transformer subdivided into an input region and an output region in a longitudinal direction, wherein the piezoelectric transformer comprises an output-side end face facing away from the input region, wherein the plasma generator comprises a passive load arranged permanently in front of the output-side end face, and wherein the plasma generator is configured to generate non-thermal atmospheric-pressure plasma.

First claim

The invention claimed is:

1. A plasma generator comprising:
a piezoelectric transformer subdivided into an input region and an output region in a longitudinal direction,
wherein the piezoelectric transformer comprises an output-side end face facing away from the input region; and
a drive electronics unit configured to:
measure at least one operating parameter of the piezoelectric transformer; and
identify, on basis of the measurement of the operating parameter, a load arranged in front of the output-side end face

wherein the plasma generator is configured in such a way that a power sufficient for igniting a non-thermal atmospheric-pressure plasma is able to be applied to the input region of the piezoelectric transformer only when a load is arranged in front of the output-side end face.

2. The plasma generator according to claim 1 , wherein the at least one operating parameter is a phase between an AC voltage applied to the input region and an AC current flowing via the piezoelectric transformer.

3. The plasma generator according to claim 2 , wherein the drive electronics unit is configured to:
operate the piezoelectric transformer, after switch-on, such that a power that is not sufficient for igniting the plasma is applied to the piezoelectric transformer and that, during operation of the piezoelectric transformer under no load, the phase between the AC voltage applied to the input region and the AC current lies in a defined range between α and β; and
increase the power applied to the piezoelectric transformer when the phase deviates from the range between α and β by a defined value.

4. The plasma generator according to claim 1 ,
wherein the at least one operating parameter is an impedance of the piezoelectric transformer, or
wherein the at least one operating parameter is a resonant frequency of the piezoelectric transformer.

5. The plasma generator according to claim 1 , further comprising:
an identifying device configured to identify an object which is arranged in front of the output-side end face of the piezoelectric transformer and which forms a load arranged in front of the output-side end face,
wherein the plasma generator is configured to apply a power sufficient for generating the plasma to the input region only when the identifying device identifies an object arranged in front of the output-side end face.

6. The plasma generator according to claim 5 , wherein the identifying device comprises a mechanical probe element, which projects beyond the output-side end face in the longitudinal direction.

7. The plasma generator according to claim 6 , wherein the mechanical probe element is arranged in such a way that the mechanical probe element is actuated by an object if the object is situated at an operating distance in front of the piezoelectric transformer.

8. The plasma generator according to claim 6 , wherein the identifying device comprises a switch, wherein the switch is configured to switch on and switch off the piezoelectric transformer, and wherein the switch is connected to the mechanical probe element such that the switch switches on the piezoelectric transformer only when the mechanical probe element identifies an object in front of the output-side end face.

9. The plasma generator according to claim 5 , wherein the identifying device comprises an optical measuring device.

10. The plasma generator according to claim 9 , wherein the optical measuring device is configured to:
emit an ultrasonic signal;
measure a reflection of the ultrasonic signal; and
carry out a distance measurement on basis of the measured reflection.

11. The plasma generator according to claim 1 , wherein the load is a passive load arranged permanently in front of the output-side end face.

12. The plasma generator according to claim 11 , wherein the load is ring-shaped and the ring-shaped load has an internal diameter that is greater than edge lengths of the output-side end face.

13. The plasma generator according to claim 11 , wherein the passive load comprises an insulating material.

14. The plasma generator according to claim 11 , further comprising a housing composed of a first material, in which the piezoelectric transformer is arranged, wherein the passive load comprises a second material, and wherein a relative permittivity of the second material is higher than a relative permittivity of the first material.

15. The plasma generator according to claim 11 , wherein the passive load consists essentially of an electrically conductive material or a semiconducting material, and wherein an insulating material is arranged between the load and the piezoelectric transformer.

16. The plasma generator according to claim 1 , wherein the output region of the piezoelectric transformer is free of an insulation material.

17. The plasma generator according to claim 1 , wherein the piezoelectric transformer is configured to ignite the plasma at its output-side end face.

18. A plasma generator comprising:
a piezoelectric transformer subdivided into an input region and an output region in a longitudinal direction,
wherein the piezoelectric transformer comprises an output-side end face facing away from the input region,
wherein the plasma generator comprises a passive load arranged permanently in front of the output-side end face,
wherein the plasma generator is configured to generate non-thermal atmospheric-pressure plasma, and
wherein the plasma generator is configured such that a power sufficient for igniting the non-thermal atmospheric-pressure plasma is able to be applied to the input region of the piezoelectric transformer.

19. The plasma generator according to claim 18 , wherein the load is ring-shaped and the ring-shaped load has an internal diameter that is greater than edge lengths of the output-side end face.

20. The plasma generator according to claim 18 , wherein the passive load comprises an insulating material.

21. The plasma generator according to claim 18 , further comprising a housing composed of a first material, in which the piezoelectric transformer is arranged, wherein the passive load comprises a second material, and wherein a relative permittivity of the second material is higher than a relative permittivity of the first material.

22. The plasma generator according to claim 18 , wherein the passive load consists essentially of an electrically conductive material or a semiconducting material, and wherein an insulating material is arranged between the load and the piezoelectric transformer.

23. The plasma generator according to claim 18 , wherein the piezoelectric transformer is configured to ignite the non-thermal atmospheric-pressure plasma at its output-side end face.

24. A plasma generator comprising:
a piezoelectric transformer subdivided into an input region and an output region in a longitudinal direction,
wherein the piezoelectric transformer comprises an output-side end face facing away from the input region,
wherein the plasma generator comprises a passive load arranged permanently in front of the output-side end face, and
wherein the plasma generator is configured to generate non-thermal atmospheric-pressure plasma; and
a housing composed of a first material, in which the piezoelectric transformer is arranged,
wherein the passive load comprises a second material, and
wherein a relative permittivity of the second material is higher than a relative permittivity of the first material.

Assignees

• Tdk Electronics Ag
• Relyon Plasma Gmbh

Inventors

• Nettesheim Stefan
• Burger Dominik
• Hoppenthaler Florian
• Weilguni Michael
• Puff Markus
• Kudela Pavol

Classifications

• H05H1/2481

  the plasma being activated using piezoelectric actuators · CPC title

• H05H1/2475 Primary

  using acoustic pressure discharges · CPC title

• H05H2001/2481

  Electricity · mapped topic

• H01L41/044

  Electricity · mapped topic

• H01L41/09

  Electricity · mapped topic