To provide an acoustic sensor which can relax the residual stress of a diaphragm or a stress acting on the diaphragm from a supporting portion although the diaphragm and a fixed plate can be used while being isolated from external atmosphere as required, and to provide a sound module with that acoustic sensor.
In the acoustic sensor, a diaphragm 4 closing the opening of a supporting portion 3 has a portion 11 which vibrates by receiving a sound wave, and a stress relaxing portion 12 coupling the vibrating portion 11 and the supporting portion 3 such that the vibrating portion 11 opposes a fixed plate 5 through a gap g of first length G1 under a state where a bias voltage is not applied between a fixed electrode 7 and a movable electrode 8. The vibrating portion 11 is attracted to the fixed plate 5 side when a bias voltage is applied and abuts against a spacer 9 to ensure a gap g of second length G2 to the fixed plate 5. The stress relaxing portion 12 employs a corrugate structure of waving cross-section in order to block transmission of stress between the supporting portion 3 and the vibrating portion 11.
KAWADA HIROSHI
YOSHIDA TAKESHI
TAKAHATA TOSHIHIKO
ARIKAWA YASUSHI
MARUYAMA HIROSHI
Atsuo Mori
Next Patent: PROCESS FOR MANUFACTURING ACOUSTIC SENSOR