US 11,915,883 B2
Electret
Noriyuki Matsushita, Kariya (JP); Yoshihiro Kozawa, Kariya (JP); Kazuhiko Kanoh, Kariya (JP); Yumi Tanaka, Tokyo (JP); Hirotoshi Otsuka, Tokyo (JP); and Yuki Kotaka, Tokyo (JP)
Assigned to DENSO CORPORATION, Kariya (JP); and TOKYO UNIVERSITY OF SCIENCE FOUNDATION, Tokyo (JP)
Filed by DENSO CORPORATION, Kariya (JP); and TOKYO UNIVERSITY OF SCIENCE FOUNDATION, Tokyo (JP)
Filed on Dec. 9, 2020, as Appl. No. 17/116,204.
Claims priority of application No. 2019-225736 (JP), filed on Dec. 13, 2019.
Prior Publication US 2021/0183584 A1, Jun. 17, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. H01G 7/02 (2006.01); C01F 17/34 (2020.01); C01B 25/32 (2006.01)
CPC H01G 7/025 (2013.01) [C01B 25/32 (2013.01); C01F 17/34 (2020.01); C01P 2002/34 (2013.01); C01P 2006/40 (2013.01)] 9 Claims
OG exemplary drawing
 
1. An electret comprising an electret layer, wherein
the electret layer is formed by subjecting a composite film in which inorganic dielectric particles are dispersed and held in a base film to a polarization treatment, and
the inorganic dielectric particles are mainly composed of an inorganic dielectric material having a bandgap energy of 4 eV or more.