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CN-122029840-A - Electroacoustic plasma transducer system

CN122029840ACN 122029840 ACN122029840 ACN 122029840ACN-122029840-A

Abstract

An electroacoustic plasma transducer system (50) comprising an electroacoustic plasma transducer device (100) comprising a plasma electrode assembly (110) comprising an inner electrode (120) and an outer electrode (130) separated from the inner electrode by an air gap (140), a peripheral support (150) for supporting the plasma electrode assembly, and a housing (170) accommodating the plasma electrode assembly, and driving means for providing a voltage U (t) between a corona electrode and a collector electrode of the electroacoustic plasma transducer device, wherein the housing is airtight and further comprising at least one gas impermeable membrane (190) for allowing acoustic energy to be transmitted from the interior of the housing to the exterior of the housing.

Inventors

  • MARK DONALDSON

Assignees

  • 索尼克奥斯公司

Dates

Publication Date
20260512
Application Date
20241022
Priority Date
20231027

Claims (14)

  1. 1. An electroacoustic plasma transducer system, comprising: An electroacoustic plasma transducer device, comprising: a plasma electrode assembly comprising an inner electrode and an outer electrode separated from the inner electrode by an air gap; a peripheral support for supporting the plasma electrode assembly, and A housing accommodating the plasma electrode assembly, and Driving means for providing a voltage U (t) between a corona electrode and a collector electrode of the electroacoustic plasma transducer means; Wherein the housing is hermetically sealed and further comprises at least one gas impermeable membrane for allowing transmission of acoustic energy from the interior of the housing to the exterior of the housing.
  2. 2. The electro-acoustic plasma transducer system of claim 1, wherein the housing comprises at least one opening and the at least one gas impermeable membrane seals the at least one opening.
  3. 3. The electroacoustic plasma transducer system of claim 2, wherein the at least one opening is associated with a primary output of the electroacoustic electrode assembly.
  4. 4. An electroacoustic plasma transducer system according to any of the preceding claims, wherein the thickness of the gas impermeable membrane is less than 400 micrometers.
  5. 5. The electro-acoustic plasma transducer system of claim 4, wherein the gas impermeable membrane has a thickness of 10-200 microns.
  6. 6. An electroacoustic plasma transducer system according to any of the preceding claims, wherein the enclosure is substantially filled with a gas other than air.
  7. 7. The electroacoustic plasma transducer system of claim 6, wherein the gas other than air is selected to provide one or more of: a) Reducing oxidation of the plasma electrode assembly and/or reducing ozone generation relative to air; b) Reducing the effective breakdown voltage and/or reducing the corona onset voltage (CIV) relative to air; c) The ion generation efficiency is improved relative to air.
  8. 8. The electro-acoustic plasma transducer system of claim 6 or 7, wherein the gas other than air comprises at least one inert gas.
  9. 9. The electro-acoustic plasma transducer system of claim 8, wherein the at least one inert gas is a non-oxidizing gas or a non-ozone generating gas.
  10. 10. The electroacoustic plasma transducer system of claim 8 or 9, wherein the at least one inert gas comprises one or more of nitrogen, a noble gas, and an inert gas compound.
  11. 11. The electro-acoustic plasma transducer system of any of claims 8-10, wherein the gas other than air comprises an inert gas mixture.
  12. 12. The electro-acoustic plasma transducer system of any of claims 6-11, wherein the enclosure comprises a mixture of a gas other than air and air.
  13. 13. An electroacoustic plasma transducer system according to any of the preceding claims, wherein the electroacoustic plasma transducer device further comprises a pressure balancing system for balancing static pressure within the enclosure with external pressure.
  14. 14. An active noise reduction system comprising: The electroacoustic plasma transducer system of any of claims 1-13; acoustic sensing device, and An active noise reduction circuit for receiving signals from the acoustic sensing device and controlling the output of the electroacoustic plasma transducer system to reduce noise.

Description

Electroacoustic plasma transducer system Technical Field The present invention relates to an electroacoustic plasma transducer system, and in particular, but not exclusively, to an electroacoustic plasma transducer system for use as part of an Active Noise Reduction (ANR) system employing acoustic impedance control. Background US2023020879A1 discloses an active noise reduction system using an electroacoustic plasma transducer with acoustic impedance control. While the use of electroacoustic plasma transducer technology in active noise reduction has significant advantages, one key issue is the generation of ozone by-product during plasma generation (which can be detrimental at high concentrations). The present inventors have recognized a need for a new electroacoustic plasma transducer device that solves or at least alleviates the problems associated with the prior art. Disclosure of Invention According to a first aspect of the present invention there is provided an electroacoustic plasma transducer system comprising an electroacoustic plasma transducer device comprising a plasma electrode assembly comprising an inner electrode (e.g. a corona electrode) and an outer electrode (e.g. a collector electrode) separated from the inner electrode by an air gap, a peripheral support (e.g. a frame) for supporting the plasma electrode assembly (e.g. mechanically coupling the collector electrode with the corona electrode), and a (e.g. gas-filled) housing accommodating the plasma electrode assembly, and driving means (e.g. a driving circuit) for providing a voltage U (t) between the corona electrode and the collector electrode of the electroacoustic plasma transducer device, wherein the housing is hermetically sealed and further comprises at least one (e.g. passive) gas-impermeable membrane (e.g. a substantially acoustically-permeable gas-impermeable membrane) for allowing acoustic energy to be transmitted from the interior of the housing to the exterior of the housing. The gas impermeable membrane is configured to passively transmit acoustic energy while preventing gas transmission. In this way, an electroacoustic plasma transducer system is provided which provides an improved sound generating means for active noise reduction while preventing ozone release from the electroacoustic plasma transducer means. In one embodiment, the plasma electrode assembly defines a longitudinal axis, and the inner and outer electrodes are spaced apart along the longitudinal axis. In one embodiment, the collector electrode forms an outer electrode and the corona electrode forms an inner electrode. In one embodiment, the gas impermeable membrane is disposed in front of the plasma electrode assembly (e.g., for receiving and transmitting forward acoustic radiation from the plasma electrode assembly). In one embodiment, the housing defines a rear cavity portion for receiving rearward acoustic radiation from the plasma electrode assembly. In one embodiment, the housing includes at least one opening, and the at least one gas impermeable membrane seals the at least one opening. In one embodiment, the at least one opening is associated with a primary output of the electroacoustic electrode assembly (e.g., in front of the plasma electrode assembly) and/or with a secondary output (e.g., a rear or side output, such as an acoustic port or vent). In one embodiment, the gas impermeable membrane has a thickness of less than 400 microns. In one embodiment, the gas impermeable film has a thickness of 5 to 400 microns. In one embodiment, the gas impermeable film has a thickness of 10-200 microns. In one embodiment, the gas impermeable film has a thickness of 10-100 microns. In one embodiment, the gas impermeable film has a thickness of 10-40 microns. In one embodiment, the gas impermeable film has a thickness of 40-100 microns. In one embodiment, the gas impermeable membrane is configured to have an acoustic power transmission coefficient greater than 50% over a frequency range of 0-5000 hertz. In one embodiment, the gas impermeable membrane is configured to have an acoustic power reflection coefficient of not more than 10% over a frequency range of 0-5000 hertz. In one embodiment, the gas impermeable membrane is configured to reduce the sound level produced by no more than 3 db at 5000 hz. In one embodiment, the gas impermeable membrane is formed of a flexible (e.g., flexible elastic) gas impermeable material. In one embodiment, the gas impermeable membrane comprises a mylar (e.g., mylar (tm)) or equivalent material. In one embodiment, the impermeable film is held at substantially zero tension (e.g., in a neutral, unfolded, or non-stretched configuration). In one embodiment, the gas impermeable membrane is supported by (e.g., bonded to) the outer electrode. In another embodiment, the gas impermeable membrane is longitudinally spaced from the outer electrode. In one embodiment, the gas impermeable membrane is optionally supported by (e.g., bonded to) a gas