# US 10,772,182 B2 · Device for producing a non-thermal atmospheric-pressure plasma and method for the frequency control of a piezoelectric transformer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,772,182 B2 - Document ID: US10772182B2 - Status: Granted - Kind: B2 - Application number: 16/494,271 - Filed: 2018-03-14 - Published: 2020-03-05 - Granted: 2020-09-08 - Earliest claimed: 2017-03-14 - Assignees: TDK Electronics Co., Ltd.; Relyon Plasma GmbH - Applicants: TDK Electronics AG; relyon plasma GmbH - Inventors: Michael Weilguni; Stefan Nettesheim - Web page: https://patentgrep.com/patent/US10772182B2 ## CPC - H05H 1/2475: {using acoustic pressure discharges} - H10N 30/40: with electrical input and electrical output, e.g. functioning as transformers - H10N 30/804: {for piezoelectric transformers} - H05H 1/2481: {the plasma being activated using piezoelectric actuators} - H05H: PLASMA TECHNIQUE (apparatus or processes specially adapted for producing X-rays H05G2/00); PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR ## Abstract A device for producing a non-thermal atmospheric-pressure plasma are a method for frequency control of a piezoelectric transformer are disclosed. In an embodiment a device includes a piezoelectric transformer, an activating circuit configured to apply an AC voltage at an activating frequency to the piezoelectric transformer as an input voltage and a field probe configured to measure a field strength of an electric field produced by the piezoelectric transformer, wherein the activating circuit is configured to adapt the activating frequency based on the measurement results of the field probe such that a field strength is maximized. ## Claims ### Claim 1 A device for producing a non-thermal atmospheric-pressure plasma, the device comprising: a piezoelectric transformer; an activating circuit configured to apply an AC voltage at an activating frequency to the piezoelectric transformer as an input voltage; and a field probe configured to measure a field strength of an electric field produced by the piezoelectric transformer, wherein the activating circuit is configured to adapt the activating frequency based on the measurement results of the field probe in such a way that the field strength is maximized when the device is switched on. ### Claim 2 (depends on 1) The device according to claim 1, wherein the piezoelectric transformer has an input region to which the input voltage is applicable, and wherein the piezoelectric transformer has an output region configured to produce a high voltage when the input voltage is applied to the input region so that a plasma is ignited by the high voltage. ### Claim 3 (depends on 2) The device according to claim 2, wherein the field probe is closely arranged to the output region. ### Claim 4 (depends on 1) The device according to claim 1, wherein the field probe is connected to a measuring unit, which is configured to determine at least one of a peak value of the electric field strength or a mean value of the electric field strength, wherein the activating circuit comprises a controller, which is configured to vary at least one of the activating frequency depending on the determined peak value or the determined mean value. ### Claim 5 (depends on 1) The device according to claim 1, wherein the field probe is integrated in a circuit board. ### Claim 6 (depends on 5) The device according to claim 5, wherein the circuit board has a metal coating that is arranged on a side of the circuit board that faces away from the piezoelectric transformer. ### Claim 7 (depends on 5) The device according to claim 5, wherein the circuit board is multi-layered and the field probe is formed by an inner layer of the circuit board. ### Claim 8 (depends on 1) The device according to claim 1, wherein the AC voltage comprises a rectangular signal or a triangular signal. ### Claim 9 (depends on 1) The device according to claim 1, wherein the activating circuit is configured to: adapt the activating frequency such that, based on measurement results of the field probe, the field strength is maximized when the device is switched on, and perform a correction of the activating frequency such that, based on the measurement results of the field probe at fixed time intervals during ongoing operation of the device, the activating frequency is adapted once again in such a way that the field strength is maximized. ### Claim 10 (depends on 1) The device according to claim 1, wherein the device is configured to produce excited molecules, ions or radicals. ### Claim 11 (depends on 1) The device according to claim 1, wherein the device is configured to produce at least one of OH radicals or nitrogen or ozone. ### Claim 12 A method for frequency control of a piezoelectric transformer, the method comprising: applying an AC voltage to the piezoelectric transformer at an initial activating frequency f0; changing an activating frequency in steps from the initial activating frequency until a determined activating frequency is reached; determining a field strength of an electric field produced by the piezoelectric transformer for each activating frequency by a field probe; determining the activating frequency at which the maximum field strength is obtained; and operating the piezoelectric transformer at the determined activating frequency for which the maximum field strength is obtained. ### Claim 13 (depends on 12) The method according to claim 12, wherein determining the activating frequency at which the maximum field strength is obtained comprises repeatedly determining the activating frequency at which the maximum field strength is obtained at fixed time intervals. ### Claim 14 (depends on 12) The method according to claim 12, wherein changing the activating frequency comprises: increasing or reducing the activating frequency in steps from the initial activating frequency f0 by a first increment Δf1 until the activating frequency is reached at which the maximum field strength for the first increment Δf1 obtained, and subsequently increasing or reducing the activating frequency in steps from this initial activating frequency by a second increment Δf2 until the activating frequency is reached at which the maximum field strength for the second increment Δf2 is obtained, wherein the second increment Δf2 being is less than the first increment Δf1. ### Claim 15 (depends on 12) The method according to claim 12, further comprising using the piezoelectric transformer for producing a non-thermal atmospheric pressure plasma. ### Claim 16 (depends on 15) The method according to claim 15, further comprising using the plasma for producing excited molecules, ions or radicals. ### Claim 17 (depends on 15) The method according to claim 15, further comprising using the plasma for producing at least one of hydroxyl radicals or nitrogen oxide or ozone.