Electrostatic transducer and electrostatic transducer unit

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.

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.

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.

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.