1. Foil‐Electret Microphones
2. 2) Y. Yasuno and Y. Riko, “A chronological review of production and applications of electret condenser microphones for consumer use,” 8th Int. Symp. Electrets, pp. 943–948 (1994).
3. 5) Y. Yasuno, Japanese Patent, Impedance transducer for electrostatic type acoustic transducer, PAT.1919337, Apr. (1995).