# US 10,121,956 B2 · Electroacoustic transducer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,121,956 B2 - Document ID: US10121956B2 - Status: Granted - Kind: B2 - Application number: 15/514,793 - Filed: 2015-08-31 - Published: 2017-08-03 - Granted: 2018-11-06 - Earliest claimed: 2014-10-24 - Assignees: Taiyo Yuden Co., Ltd. - Applicants: Taiyo Yuden Co., Ltd. - Inventors: Takashi Tomita; Shigeo Ishii; Hiroshi Hamada; Yutaka Doshida - Web page: https://patentgrep.com/patent/US10121956B2 ## CPC - H10N 30/871: {Single-layered electrodes of multilayer piezoelectric or electrostrictive devices, e.g. internal electrodes} - B06B 1/0611: {in a pile} - H04R 7/04: Plane diaphragms - H04R 17/00: Piezoelectric transducers; Electrostrictive transducers (piezoelectric or electrostrictive elements in general H10N30/00; details of piezoelectric or electrostrictive motors, generators or positioners {H10N30/00}) - H10N 30/063: Forming interconnections, e.g. connection electrodes of multilayered piezoelectric or electrostrictive parts - H10N 30/067: Forming single-layered electrodes of multilayered piezoelectric or electrostrictive parts - H10N 30/302: {Sensors} - H10N 30/501: {having a non-rectangular cross-section in a plane parallel to the stacking direction, e.g. polygonal or trapezoidal in side view} - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR - B06B: METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, {e.g.} FOR PERFORMING MECHANICAL WORK IN GENERAL (for particular applications, see the relevant subclasses, e.g. B07B1/40, B23Q17/12, B24B31/06; measurement of mechanical vibrations G01H; in direction finding, locating, distance or velocity measuring G01S; {generating seismic energy G01V1/02}; control of mechanical vibrations in general G05D; sound-producing devices, e.g. bells, sirens, whistles G10K, {e.g. methods or devices for transmitting, conducting, or directing sound in general G10K11/00}; generation of electrical oscillations H03B; electromechanical resonators in general H03H; electromechanical transducers {for communication techniques, e.g. microphones, speakers} H04R) - 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 An electroacoustic transducer includes: a polygonal-shaped laminated piezoelectric element including alternately stacked piezoelectric layers and electrode layers, with the piezoelectric layers placed between at least one pair of electrode layers having different polarities; and a circular vibration plate on which the laminated piezoelectric element is placed. Of the piezoelectric layers sandwiched between the at least one pair of electrode layers, the total volume (V) of those effective layers that overlap the at least one pair of electrode layers as viewed from the stacking direction satisfies the condition below: 0.2πR2×ts≤V≤2.0πR2×ts wherein π represents the ratio of the circumference of a circle to its diameter, R represents the radius of the vibration plate, and ts represents the thickness of the vibration plate. ## Claims ### Claim 1 An electroacoustic transducer, comprising: a laminated piezoelectric element comprising alternately stacked piezoelectric layers and electrode layers, with the piezoelectric layers placed between at least one pair of electrode layers having different polarities; and a vibration plate on which the laminated piezoelectric element is placed; said electroacoustic transducer is characterized in that: the laminated piezoelectric element is polygonal in shape when viewed from a stacking direction; the vibration plate on which the laminated piezoelectric element is placed is circular in shape and made of a metal; and of the piezoelectric layers sandwiched between the at least one pair of electrode layers, a total volume (V) of effective layers that overlap the at least one pair of electrode layers as viewed from the stacking direction satisfies a condition below when V is approximated by a volume of the laminated piezoelectric element: 0.2πR2×ts≤V≤2.0πR2×ts (wherein π represents a ratio of a circumference of a circle to its diameter, R represents a radius of the vibration plate, and ts represents a thickness of the vibration plate). ### Claim 2 (depends on 1) The electroacoustic transducer according to claim 1, characterized in that: the at least one pair of electrode layers include a first electrode layer and a second electrode layer having different polarities; the first electrode layer is connected to a first side electrode formed on one side face of the laminated piezoelectric element; and the second electrode layer is connected to a second side electrode formed on a side face different from the one on which the first side electrode is formed. ### Claim 3 (depends on 2) The electroacoustic transducer according to claim 2, characterized in that the first electrode layer includes an electrode layer formed on a surface of the laminated piezoelectric element on a side opposite the one that contacts the vibration plate. ### Claim 4 (depends on 1) The electroacoustic transducer according to claim 1, characterized in that the laminated piezoelectric element is square in shape when viewed from the stacking direction. ### Claim 5 (depends on 2) The electroacoustic transducer according to claim 2, characterized in that the laminated piezoelectric element is square in shape when viewed from the stacking direction. ### Claim 6 (depends on 3) The electroacoustic transducer according to claim 3, characterized in that the laminated piezoelectric element is square in shape when viewed from the stacking direction. ### Claim 7 (depends on 1) The electroacoustic transducer according to claim 1, wherein the vibration plate has a thickness of 0.05-0.5 mm. ### Claim 8 (depends on 2) The electroacoustic transducer according to claim 2, wherein the vibration plate has a thickness of 0.05-0.5 mm. ### Claim 9 (depends on 3) The electroacoustic transducer according to claim 3, wherein the vibration plate has a thickness of 0.05-0.5 mm.