Patent ID: 6999596

Claim:
A condenser sensor, comprising: an electrically conductive case having an opening portion formed therein and an opposing portion opposing to and spaced apart from said opening portion; a fixed electrode received in said electrically conductive case through said opening portion; an electrically conductive diaphragm accommodated in said electrically conductive case, said electrically conductive diaphragm spaced apart from said fixed electrode and opposing to said opening portion; an electrically conductive diaphragm supporting member disposed in said electrically conductive case to support said diaphragm; a circuit packaging board disposed in said electrically conductive case to be held in electrical contact with said fixed electrode and said diaphragm respectively through said electrically conductive case and said diaphragm supporting member; and a deformation protecting member for protecting said opposing portion from being deformed, in which said deformation protecting member intervenes between said electrically conductive case and said diaphragm, said deformation protecting member is disposed inwardly of a circumference of an oscillatable portion of said diaphragm, said electrically conductive case and said fixed electrode are respectively formed with acoustic apertures, a total area of said acoustic aperture formed in said electrically conductive case is larger than a total area of said acoustic aperture formed in said fixed electrode, and said total area of said acoustic aperture formed in said fixed electrode is larger than one thousandth of a total area of said oscillatable portion of said diaphragm but smaller than one tenth of said total area of said oscillatable portion of said diaphragm.