64 elements two-dimensional piezoelectric array for 3D imaging

Area of Science:

• Materials Science
• Acoustics
• Engineering

Background:

• Ultrasound technology is vital for non-invasive inspection in medical imaging and non-destructive testing (NDT).
• Advancements in 3D imaging necessitate innovative 2D ultrasonic array designs that minimize electronic channels without compromising resolution.
• 2D segmented annular arrays (SAAs) provide an effective solution, balancing resolution, image quality, and channel requirements.

Purpose of the Study:

• To design, manufacture, and test a 1.5 MHz 2D segmented annular array (SAA) with 64 elements and a 20 mm diameter.
• To explore the use of 1-3 piezoelectric composites for array transducers, optimizing electromechanical properties.
• To validate the array's performance through electrical, acoustic, and field measurements against simulation models.

Main Methods:

• A 1.5 MHz SAA was designed using a flexible circuit for electrode and track definition on a 1-3 piezoelectric composite.
• The array incorporated a soft backing and one matching layer.
• Electrical and acoustic testing, along with acoustical field measurements at various steering angles, were conducted and compared with KLM and impulse response models.

Main Results:

• The manufactured SAA demonstrated good agreement between electrical/acoustic tests and KLM-based simulations.
• Acoustical field measurements correlated well with simulations using an exact impulse response approach.
• The study identified that the current array geometry, optimized for metals in NDT, produces significant side lobes, suggesting smaller elements for medical applications.

Conclusions:

• The developed 1.5 MHz SAA using 1-3 piezoelectric composites is a viable solution for NDT applications.
• The flexible circuit design facilitates array geometry definition.
• Further optimization with smaller elements is recommended for medical imaging to mitigate side lobe effects.