Phase aberration correction in two dimensions with an integrated deformable actuator/transducer

Abstract

Two-dimensional arrays are required to implement two-dimensional phase aberration correction using traditional electronic correction techniques. A new transducer design, deformable in the elevation dimension, can be used to implement two-dimensional phase correction without using a full two-dimensional array. Phase correction in azimuth is achieved by altering the electronic phase delays of the elements. Phase correction in elevation is achieved by tilting the elements in elevation with piezoelectric actuators. Previously, such deformable arrays were fabricated by bonding PZT array elements to low frequency actuators. The construction of deformable arrays is simplified by using the actuator for both the element deflection and the generation of ultrasound. The new construction technique was used to fabricate a prototype 1/spl times/32 deformable array with a 3.5 MHz center frequency and an actuator flexure resonance of 3/spl deg/ at 1.3 kHz with a 300 Vpp sine wave. The prototype array was characterized and used to make B-scan images. Phase correction was simulated by tilting the elements on-line to alter the B-scan image and resulted in a cyst contrast reduction from 0.86 for the control to 0.76 with the elements tilted. Further characterization of the deformable array performance includes the frequency response of the actuator. Initial results from a 2/spl times/32 deformable array fabricated with the new construction technique are also presented. The 2/spl times/32 array configuration additionally offers the potential for on-line elevation focusing.