Patent ID: 6091181
Filing Date: 2000-07-18
Classification: H04R

Abstract:
A piezoelectric acoustic device comprising:a piezoelectric vibrator comprising a piezoelectric ceramic element joined to a metal vibrating plate;a casing for receiving said piezoelectric vibrator;said casing comprising a first casing half and a second casing half that when joined together define a space therebetween for receiving said piezoelectric vibrator, said first casing half comprising a first side wall disposed opposite said piezoelectric vibrator, said first side wall having an inner surface and an outer surface and a first peripheral wall extending from the periphery of said first side wall in a direction toward the junction with said second casing half;said first side wall being spaced apart from said piezoelectric vibrator so as to form a front air chamber between said inner surface of said first side wall and said piezoelectric vibrator; andsaid first side wall having a cylinder integrally formed on said outer surface thereof extending perpendicular to the plane of said first side wall, said cylinder including a base defined as that portion of said cylinder that is disposed adjacent to said first side wall;said cylinder having a diameter less than the diameter of said first side wall, said cylinder defining a passage that is connected to said front air chamber by an opening through said first side wall;said cylinder being disposed toward an outer peripheral portion of said first side wall such that said base of said cylinder is rendered opposite at a part thereof to a part of said first peripheral wall.