| 摘要 |
PROBLEM TO BE SOLVED: To provide a technique for enhancing the SN ratio by suppressing increase in noise, while increasing sensitivity by raising the surface potential.SOLUTION: An electret capacitor microphone includes a vibration membrane 20 vibrating by sound, a backplate 30 arranged oppositely to the vibration membrane 20, and having a plurality of through holes 35 interconnecting a space on the vibration membrane side and a space on the opposite side thereof, and an electret layer 40 formed on the surface of the backplate 30 on the vibration membrane side. On the vibration membrane side of a through holes 35 in the backplate 30, an opening of such a shape as a hole is widened toward an opening on the vibration membrane side is provided. The electret layer 40 is formed on a surface of the backplate 30 facing the vibration membrane 20 in parallel, and on a surface of the opening of the through hole 35. |
