US 12,071,761 B2
Sound reducing system
Yusuke Komoto, Osaka (JP); Tomoaki Hishiki, Osaka (JP); Kohei Oto, Osaka (JP); Saori Yamamoto, Osaka (JP); and Yuka Sekiguchi, Osaka (JP)
Assigned to NITTO DENKO CORPORATION, Osaka (JP)
Appl. No. 16/765,411
Filed by NITTO DENKO CORPORATION, Ibaraki (JP)
PCT Filed Nov. 20, 2018, PCT No. PCT/JP2018/042909
§ 371(c)(1), (2) Date May 19, 2020,
PCT Pub. No. WO2019/103017, PCT Pub. Date May 31, 2019.
Claims priority of application No. 2017-223799 (JP), filed on Nov. 21, 2017.
Prior Publication US 2020/0332518 A1, Oct. 22, 2020
Int. Cl. E04B 1/82 (2006.01); H04R 17/00 (2006.01)
CPC E04B 1/8209 (2013.01) [H04R 17/005 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A sound reducing system comprising:
at least one sound reducing speaker for radiating a sound wave for sound reduction, the at least one sound reducing speaker comprising:
a piezoelectric speaker that comprises:
a piezoelectric film,
a fixing face in contact with a support supporting the piezoelectric speaker, and
a film holding portion disposed between the piezoelectric film and the fixing face, and wherein at least one of:
(i) the film holding portion comprises a pressure-sensitive adhesive layer and the fixing face is formed of a surface of the pressure-sensitive adhesive layer or
(ii) the film holding portion comprises a porous body layer, wherein the film holding portion includes an interposed layer, and the interposed layer is an ethylene propylene rubber foam layer having a porosity of 70% to 99%,
 wherein, in a state in which the piezoelectric film is held by the interposed layer, extension and contraction of the piezoelectric film in an in-plane direction of the piezoelectric film is converted into deformation of the piezoelectric film in a thickness direction of the piezoelectric film to bend the piezoelectric film and to generate sound from the piezoelectric film.