Implementation of a PMN-PT piezocrystal-based focused array with geodesic faceted structure.

Area of Science:

• Materials Science
• Acoustics
• Biomedical Engineering

Background:

• Relaxor-based piezocrystals offer superior performance over piezoceramics for ultrasound imaging.
• Current limitations exist for using piezocrystals in focused ultrasound applications, such as targeted drug delivery, due to difficulties in shaping anisotropic materials into spherical geometries.

Purpose of the Study:

• To develop a novel method for fabricating focused ultrasound arrays using flat piezocrystal material.
• To overcome the challenges associated with shaping anisotropic piezocrystals into spherical geometries for focused ultrasound applications.

Main Methods:

• A novel faceted geodesic array design was developed, inspired by geodesic domes, to maximize fill factor using flat piezocrystal material.
• A prototype array with 96 individually addressable elements using 1-3 connectivity PMN-PT piezocrystal-epoxy composite was manufactured using 3D printing.
• The array was connected to a 32-channel controller for beam shaping and steering.

Main Results:

• A prototype focused ultrasound array with f#≈1.2 was successfully manufactured.
• Preliminary performance demonstration at 1MHz showed a focusing gain of approximately 30.
• Side lobe intensities were maintained below -12dB relative to the main beam.

Conclusions:

• The geodesic array configuration is a viable solution for creating focused ultrasound devices with piezocrystals.
• Contemporary fabrication techniques and driving instrumentation enable the use of this novel array design for advanced applications.