Patent ID: 8327711
Filing Date: 2012-12-11
Classification: H04R

Abstract:
1. An electrostatic capacitive vibration sensor comprising: a substrate; a through-hole penetrating the substrate; a vibrating electrode plate; and a fixed electrode plate opposite the vibrating electrode plate; wherein the fixed electrode plate is subjected to vibration to perform membrane oscillation, a plurality of acoustic holes are made in the fixed electrode plate, the vibrating electrode plate and the fixed electrode plate are disposed on a surface side of the substrate such that an opening on the surface side of the substrate of the through-hole is covered therewith, a lower surface of an outer peripheral portion of the vibrating electrode plate is partially fixed to the substrate, a vent hole that communicates a surface side and a rear surface side of the vibrating electrode plate with each other is made between the surface of the substrate and the lower surface of the vibrating electrode plate, and in a region opposite to the vibrating electrode plate in the fixed electrode plate, an opening area of the acoustic hole of the outer peripheral portion is smaller than an average value of opening areas of the acoustic holes in an inside region.