Patent ID: 6628047
Filing Date: 2003-09-30
Classification: B06B,H04R

Abstract:
In a broadband ultrasonic transducer comprising a layer of piezoelectric material sandwiched between a layer of backing material and a layer of matching material, said piezoelectric layer having a back surface to which said backing layer is bonded and a front surface to which said matching layer is bonded, and means for applying a varying voltage across said piezoelectric layer which produces a first exciting wave at said front surface and a second exciting wave at said back surface. said front surface of said piezoelectric layer having a smoothness which does not low-pass filter said first exciting wave and produces a first forward-propagating wave having a first waveform and a first polarity which emanates from said front surface, the improvement wherein said back surface of said piezoelectric layer has a rough texture which low-pass filters said second exciting wave to produce a second forward-propagating wave emanating from said back surface has a second waveform different than said first waveform and a second polarity opposite to said first polarity, thereby mitigating destructive interference between said first and second forward-propagating waves when the frequency of said exciting waves is an even multiple of the half-wave frequency for said piezoelectric layer.