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US 4,413,198 AGranted
Piezoelectric transducer apparatus
AssigneeMotorola, Inc.
InventorJonathan R. Bost
Life of this patent
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Abstract
An electroacoustic loudspeaker apparatus is provided including a piezoelectric driver element, the opposed major surfaces of which are acoustically coupled into first and second resonant structures. The first resonant structure exhibits a resonant frequency less than the resonant frequency of the driver and the second resonant structure exhibits a resonant frequency greater than the resonant frequency of the driver thus resulting in a broadened or enhanced frequency response.
Claims4
An electroacoustic device comprising:
- piezoelectric driver means, having opposed major surfaces, for converting electrical signals applied thereto into acoustic energy radiating from each of said major surfaces, said driver means exhibiting a first predetermined resonant frequency;
- first Helmholtz resonator means, acoustically coupled to one major surface of said driver means, and exhibiting appropriate dimensions for resonating at a second resonant frequency less than said first resonant frequency, and
- second Helmholtz resonator means, acoustically coupled to the remaining major surface of said driver means, and exhibiting appropriate dimensions for resonating at a third resonant frequency greater than said first resonant frequency.
Dependencies are inferred from the claim text.