# US 12,015,898 B2 · Transducer and driving method thereof, and system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,015,898 B2 - Document ID: US12015898B2 - Status: Granted - Kind: B2 - Application number: 17/979,419 - Filed: 2022-11-02 - Published: 2023-02-16 - Granted: 2024-06-18 - Earliest claimed: 2020-05-20 - Assignees: Rohm Co., Ltd. - Applicants: Rohm Co., Ltd. - Inventors: Takashi Naiki; Tomohiro Date; Noriyuki Shimoji - Web page: https://patentgrep.com/patent/US12015898B2 ## CPC - H04R 17/10: Resonant transducers, i.e. adapted to produce maximum output at a predetermined frequency - H04R 7/10: comprising superposed layers in contact - H04R 7/18: at the periphery - H04R 17/02: Microphones - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) ## Abstract A transducer includes: a piezoelectric element; and a film body including a film support portion having a hollow portion, and a vibration film connected to the film support portion and displaceable in a film thickness direction, the film body having the piezoelectric element stacked over the vibration film. The piezoelectric element includes: a first stacked body having a first pair of electrodes and a first piezoelectric film sandwiched between the first pair of electrodes; and a second stacked body having a second pair of electrodes and a second piezoelectric film sandwiched between the second pair of electrodes, the second stacked body being separated from the first stacked body. ## Claims ### Claim 1 A transducer comprising: a piezoelectric element; and a film body including a film support portion having a hollow portion, and a vibration film connected to the film support portion and displaceable in a film thickness direction, the film body having the piezoelectric element stacked over the vibration film, wherein the piezoelectric element includes: a first stacked body having a first pair of electrodes and a first piezoelectric filth sandwiched between the first pair of electrodes; and a second stacked body having a second pair of electrodes and a second piezoelectric film sandwiched between the second pair of electrodes, the second stacked body being separated from the first stacked body; the piezoelectric element and the film body form a vibration body; and the first stacked body and the second stacked body each have a driving voltage applied thereto, and are configured to be driven individually by the driving voltages respectively applied thereto to thereby change a resonant frequency of the vibration body. ### Claim 2 (depends on 1) The transducer according to claim 1, wherein the piezoelectric element further includes a third stacked body having a third pair of electrodes and a third piezoelectric film sandwiched between the third pair of electrodes, and the third stacked body is sandwiched between the first stacked body and the second stacked body, and is separated from the first stacked body and the second stacked body. ### Claim 3 (depends on 1) The transducer according to claim 1, wherein an end of the second stacked body has a region overlapping the film support portion when viewed from a direction normal to the vibration film. ### Claim 4 (depends on 1) The transducer according to claim 1, wherein the first stacked body is surrounded by the second stacked body. ### Claim 5 (depends on 1) The transducer according to claim 1, wherein the vibration film has a double-sided beam shape. ### Claim 6 A transducer comprising: a piezoelectric element; and a film body including a film support portion having a hollow portion, and a vibration film connected to the film support portion and displaceable in a film thickness direction, the film body having the piezoelectric element stacked over the vibration film, wherein the piezoelectric element includes: a first electrode; a first stacked body having a first piezoelectric film and a second electrode; and a second stacked body having a second piezoelectric film and a third electrode, and separated from the first stacked body; the first piezoelectric film is sandwiched between the first electrode and the second electrode; the second piezoelectric film is sandwiched between the first electrode and the third electrode; the piezoelectric element and the film body form a vibration body; and the first stacked body and the second stacked body each have a driving voltage applied thereto, and are configured to be driven individually by the driving voltages respectively applied thereto to thereby change a resonant frequency of the vibration body. ### Claim 7 (depends on 6) The transducer according to claim 6, wherein the first piezoelectric film and the second piezoelectric film are positioned over the first electrode. ### Claim 8 (depends on 6) The transducer according to claim 6, wherein the piezoelectric element further includes a third stacked body having a third piezoelectric film and a fourth electrode, and the third stacked body is sandwiched between the first stacked body and the second stacked body, and is separated from the first stacked body and the second stacked body. ### Claim 9 (depends on 6) The transducer according to claim 6, wherein an end of the second stacked body has a region overlapping the film support portion when viewed from a direction normal to the vibration film. ### Claim 10 (depends on 6) The transducer according to claim 6, wherein the first stacked body is surrounded by the second stacked body. ### Claim 11 (depends on 6) The transducer according to claim 6, wherein the vibration film has a double-sided beam shape. ### Claim 12 A transducer comprising: a piezoelectric element; and a film body including a film support portion having a hollow portion, and a vibration film connected to the film support portion and displaceable in a film thickness direction, the film body having the piezoelectric element stacked over the vibration film, wherein the piezoelectric element includes: a first electrode; a second electrode; a piezoelectric film sandwiched between the first electrode and the second electrode; and a third electrode; the piezoelectric film is sandwiched between the first electrode and the third electrode; the third electrode is separated from the second electrode; each of the second electrode and the third electrode has a driving voltage applied thereto; the piezoelectric element and the film body form a vibration body; and the piezoelectric element is configured to change a resonant frequency of the vibration body by controlling the driving voltages applied to the second electrode and the third electrode individually. ### Claim 13 (depends on 12) The transducer according to claim 12, wherein an end of the third electrode has a region overlapping the film support portion when viewed from a direction normal to the vibration film. ### Claim 14 (depends on 12) The transducer according to claim 12, wherein the vibration film is positioned over the first electrode. ### Claim 15 (depends on 12) The transducer according to claim 12, wherein the piezoelectric element further includes a fourth electrode, the piezoelectric film is sandwiched between the first electrode and the fourth electrode, and the fourth electrode is sandwiched between the second electrode and the third electrode, and is separated from the second electrode and the third electrode. ### Claim 16 (depends on 12) The transducer according to claim 12, wherein the second electrode is surrounded by the third electrode. ### Claim 17 (depends on 12) The transducer according to claim 12, wherein the vibration film has a double-sided beam shape.