Piezoelectric element for radio loudspeaker - includes piezoelectric plate with main and auxiliary weights attached to visco-elastic layers on opposed faces

摘要

A vibrating piezoelectric element is provided with a main weight (104) fixed near to the centre of a piezoelectric accoustic radiator (101-102). The weight is attached by a viscoelastic layer (103) so that the plate is held so as at to deliver a vibrating force to its outer edge. An auxiliary weight (110) is attached by a further viscoelastic layer (109) to the opposite surface of the plate, at a radial position between the main weight and the edge. The auxiliary weight (110) is in the form of an open ring of diameter larger than the main weight. ADVANTAGE - Small diameter loudspeaker with improved range of frequency response.