Electro-mechanical transducer, an electro-mechanical converter, and manufacturing methods of the same

摘要

An electro-mechanical transducer contains a vibrating electrode (15b), a vibrating-electrode-insulating film (15a) disposed at a bottom surface of the vibrating electrode (15b), an electret layer (13) facing to the vibrating electrode (15b), an electret-insulating layer (14e) joined to a top surface of the electret layer (13), and a back electrode 17 in contact with a bottom surface of the electret layer (13). A microgap between ten nanometers and 100 micrometers is established between the vibrating-electrode-insulating film (15a) and electret-insulating layer (14e). A central line average roughness Ra of the vibrating electrode (15b), including a bending, is 1/10 or less of a gap width measured between the bottom surface of the vibrating electrode (15b) and the top surface of the electret layer (13).