Stretchable Ultrasonic Transducer Arrays for Three-Dimensional Imaging on Complex Surfaces

Ultrasonic imaging technology has been widely implemented in the fields of medical imaging, non-destructive evaluation, and structural health monitoring. Tradition- ally, rigid and semi-flexible ultrasound probes in current bulky packages can detect the sub-surface defects of a component with a flat surface, but neither is suitable for the accurate defect inspection with three-dimensional curvatures, which significantly constrains the universality and practicability of ultrasonic imaging technology. This study reports the development of flexible and stretchable ultrasound two-dimensional (2D) array probe that exploits an ’island-bridge’ structured interconnection and multi-layer electrodes to integrate miniature ultrasound transducer elements with thin, low modulus silicone elastomeric polymer matrix. The achieved soft device, owning dense transducer distribution, excellent piezoelectric performance, bare internal cross-talk, and over 60% stretchability, is capable of long-time seamlessly conforming on almost any curved com- ponents, and reconstructing the object images with high resolution. With the designed probe, mono-view 2D images of internal defects in a specimen with a convex surface are collected. The entire geometries of two internal defects are reconstructed in threedimensional space. The proposed flexible and stretchable ultrasonic device along with the imaging reconstruction algorithm provides an effective, accurate, and straightforward solution for ultrasonic imaging of complex-shaped structure components.