# US 12,007,520 B2 · Electrostatic transducer and electrostatic transducer unit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,007,520 B2 - Document ID: US12007520B2 - Status: Granted - Kind: B2 - Application number: 17/368,846 - Filed: 2021-07-07 - Published: 2021-10-28 - Granted: 2024-06-11 - Earliest claimed: 2019-03-28 - Assignees: Sumitomo Riko Company Limited - Applicants: Sumitomo Riko Company Limited - Inventors: Katsuhiko Nakano; Shinya Tahara; Masaki Nasu - Web page: https://patentgrep.com/patent/US12007520B2 ## CPC - G01V 3/088: {operating with electric fields (G01V3/082 takes precedence)} - B06B 1/0292: {Electrostatic transducers, e.g. electret-type} - B60R 21/01552: {detecting position of specific human body parts, e.g. face, eyes or hands} - G01D 5/241: by relative movement of capacitor electrodes - H04R 19/00: Electrostatic transducers - H04R 19/02: Loudspeakers (H04R19/01 takes precedence) - H04R 19/04: Microphones (H04R19/01 takes precedence) - G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02) - 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) - B60R: VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR - 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 Provided is an electrostatic transducer capable of reducing thickness and enhancing detection precision or operation precision. An electrostatic transducer (1) includes an insulating sheet (11), a first electrode sheet (12) arranged on the front surface side of the insulating sheet (11) and having a plurality of first through holes (12a) penetrating in a thickness direction, and a second electrode sheet (13) arranged on the back surface side of the insulating sheet (11) and having no through holes in the thickness direction or having a plurality of second through holes (13a) which have a smaller aperture ratio than the plurality of first through holes (12a). ## Claims ### Claim 1 An electrostatic transducer comprising: an insulating sheet, a first electrode sheet arranged on a front surface side of the insulating sheet and having a plurality of first through holes penetrating in a thickness direction, and a second electrode sheet arranged on a back surface side of the insulating sheet, having a plurality of second through holes in the thickness direction and functioning as a shield electrode, wherein an aperture ratio of the plurality of second through holes is smaller than an aperture ratio of the plurality of first through holes. ### Claim 2 (depends on 1) The electrostatic transducer according to claim 1, wherein an aperture area of each of the second through holes is smaller than an aperture area of each of the first through holes. ### Claim 3 (depends on 1) The electrostatic transducer according to claim 1, wherein a diameter of an inscribed circle of the first through hole is set to 150 μm or more and 15 mm or less. ### Claim 4 (depends on 1) The electrostatic transducer according to claim 1, wherein the aperture ratio of the plurality of first through holes is 30% or more. ### Claim 5 (depends on 1) The electrostatic transducer according to claim 1, wherein the first electrode sheet has at least two detection regions, and the at least two detection regions each have the first through holes having different aperture areas. ### Claim 6 (depends on 1) The electrostatic transducer according to claim 1, wherein the first electrode sheet has at least two detection regions, and the at least two detection regions have different thicknesses. ### Claim 7 (depends on 1) The electrostatic transducer according to claim 1, wherein the insulating sheet is formed of an elastomer, and the first electrode sheet and the second electrode sheet are fixed to the insulating sheet by fusion bonding of the insulating sheet itself. ### Claim 8 (depends on 7) The electrostatic transducer according to claim 7, wherein the first electrode sheet and the second electrode sheet are embedded in the insulating sheet. ### Claim 9 (depends on 7) The electrostatic transducer according to claim 7, wherein the first electrode sheet and the second electrode sheet are formed of an elastomer containing a conductive filler. ### Claim 10 An electrostatic transducer comprising: an insulating sheet, a first electrode sheet arranged on a front surface side of the insulating sheet and having a plurality of first through holes penetrating in a thickness direction, and a second electrode sheet arranged on a back surface side of the insulating sheet, and having no through holes or having a plurality of second through holes in the thickness direction, wherein an aperture ratio of the plurality of second through holes is smaller than an aperture ratio of the plurality of first through holes, wherein the insulating sheet is formed of an elastomer, the first electrode sheet and the second electrode sheet are fixed to the insulating sheet by fusion bonding of the insulating sheet itself, the first electrode sheet and the second electrode sheet are embedded in the insulating sheet, at least a part of the first electrode sheet is embedded in the insulating sheet, the insulating sheet comprises a first coating layer formed by a part of the insulating sheet on a front surface side of the first electrode sheet, and at least a part of a front surface of the first electrode sheet is fixed to the first coating layer by fusion bonding of the first coating layer itself. ### Claim 11 An electrostatic transducer comprising: an insulating sheet, a first electrode sheet arranged on a front surface side of the insulating sheet and having a plurality of first through holes penetrating in a thickness direction, and a second electrode sheet arranged on a back surface side of the insulating sheet, and having a plurality of second through holes in the thickness direction and functioning as a shield electrode, wherein an aperture ratio of the plurality of second through holes is smaller than an aperture ratio of the plurality of first through holes, wherein the insulating sheet is formed of a styrene elastomer or an olefin elastomer. ### Claim 12 (depends on 11) The electrostatic transducer according to claim 11, wherein the first electrode sheet is formed of a styrene elastomer or an olefin elastomer, and a softening point of the first electrode sheet is higher than a softening point of the insulating sheet. ### Claim 13 An electrostatic transducer comprising: an insulating sheet, a first electrode sheet arranged on a front surface side of the insulating sheet and having a plurality of first through holes penetrating in a thickness direction, a second electrode sheet arranged on a back surface side of the insulating sheet, and having a plurality of second through holes in the thickness direction and functioning as a shield electrode, wherein an aperture ratio of the plurality of second through holes is smaller than an aperture ratio of the plurality of first through holes, and a heater sheet laminated on a back surface side of the second electrode sheet. ### Claim 14 (depends on 13) The electrostatic transducer according to claim 13, wherein the insulating sheet has a thermal conductivity of 0.3 W/m·K or more. ### Claim 15 (depends on 14) The electrostatic transducer according to claim 14, wherein the insulating sheet has a thermally conductive filler having a thermal conductivity of 5 W/m·K or more. ### Claim 16 (depends on 15) The electrostatic transducer according to claim 15, wherein the thermally conductive filler is an insulating metal filler. ### Claim 17 (depends on 13) The electrostatic transducer according to claim 13, wherein the insulating sheet has a flame-retardant filler. ### Claim 18 (depends on 17) The electrostatic transducer according to claim 17, wherein the flame-retardant filler is a hydroxide filler. ### Claim 19 An electrostatic transducer unit comprising: a core material having a center line, an electrostatic transducer, comprising: an insulating sheet, a first electrode sheet arranged on a front surface side of the insulating sheet and having a plurality of first through holes penetrating in a thickness direction, a second electrode sheet arranged on a back surface side of the insulating sheet, and having no through holes or having a plurality of second through holes in the thickness direction, wherein an aperture ratio of the plurality of second through holes is smaller than an aperture ratio of the plurality of first through holes, wherein the electrostatic transducer is arranged along an outer peripheral surface of the core material so that the back surface of the second electrode sheet faces the outer peripheral surface of the core material centering on the center line, and a resin inner layer material interposed between the outer peripheral surface of the core material and a back surface of the electrostatic transducer, and fixed to the core material and the electrostatic transducer, wherein in the electrostatic transducer, end sides in a circumferential direction of the outer peripheral surface of the core material are defined as first end sides, two first end sides of the electrostatic transducer are arranged opposite to each other with a space therebetween in the circumferential direction of the outer peripheral surface of the core material, and the resin inner layer material is interposed in the space between the two first end sides. ### Claim 20 (depends on 19) The electrostatic transducer unit according to claim 19, wherein the electrostatic transducer has a first terminal portion or a first wire electrically connected to the first electrode sheet, and the first terminal portion or the first wire is arranged in the space between the two opposing first end sides. ### Claim 21 (depends on 19) The electrostatic transducer unit according to claim 19, wherein the electrostatic transducer has, in a region where the first electrode sheet and the second electrode sheet are not arranged, at least one third through hole penetrating in the thickness direction and functioning as a resin injection hole or an air vent hole at the time of resin injection, and the resin inner layer material is arranged in the third through hole. ### Claim 22 (depends on 21) The electrostatic transducer unit according to claim 21, wherein the electrostatic transducer has a first terminal portion or a first wire electrically connected to the first electrode sheet, and the first terminal portion or the first wire is arranged in the third through hole. ### Claim 23 (depends on 19) The electrostatic transducer unit according to claim 19, wherein the core material has a shape in which the center line is formed in a ring shape, in the electrostatic transducer, end sides in a ring shaped circling direction of the core material are defined as second end sides, two second end sides of the electrostatic transducer are arranged opposite to each other with a space therebetween in the ring shaped circling direction of the core material, and the resin inner layer material is interposed in the space between the two second end sides. ### Claim 24 (depends on 23) The electrostatic transducer unit according to claim 23, wherein the electrostatic transducer has a first terminal portion or a first wire electrically connected to the first electrode sheet, and the first terminal portion or the first wire is arranged in the space between the two opposing second end sides. ### Claim 25 (depends on 19) The electrostatic transducer unit according to claim 19, wherein the electrostatic transducer further comprises a heater sheet arranged on the back surface side of the second electrode sheet, and the resin inner layer material is fixed to the heater sheet. ### Claim 26 (depends on 19) The electrostatic transducer unit according to claim 19, wherein the electrostatic transducer has a second terminal portion or a second wire electrically connected to the second electrode sheet, and the second terminal portion or the second wire is arranged in the space between the two opposing first end sides.