Adjustable Acoustic Field Controlled by "Ultrasonic Projector" on Ultrasound Application.

Abstract

The control of acoustic field has great potential in many applications such as medical treatment, neuro-modulation, and bio-imaging. Recently, acoustic lenses and phased arrays have become common ways of controlling acoustic fields. However, the shortcomings of the two ways are obvious. Acoustic lenses lack flexibility after design, and phased arrays have complicated structures and need to adjust the parameters of each array element. In this work, we propose an alternative for sound field control using a flexible and adjustable "acoustic projector," and two symmetric mirrors are used to change the direction of propagation of an acoustic wave produced by a piezoelectric element and realize acoustic focusing in the target region. The 2-D "acoustic projector" model was built in finite element simulation, and the feasibility was verified with an actual prototype. The sound intensity produced by the piezoelectric element at different horizontal and vertical positions along the target area can be accurately controlled by two adjustable mirrors. When the angle of the mirror ranges from 30° to 40°, the focal depth can change from 39 to 140 mm. Furthermore, the focus can be controlled in a sector with an angle of 60°. The "acoustic projector" demonstrates simple but precise control of acoustic fields and may broaden their applicability. To show its imaging ability, the three groups of target balls at different positions were imaged and their position information by scanning the mirrors in simulation was given.