Stretchable ultrasonic transducer arrays for three-dimensional imaging on complex surfaces

Abstract

Ultrasound adds the third dimension to wearable sensors.

Ultrasound‐Induced Wireless Energy Harvesting for Potential Retinal Electrical Stimulation Application

“…The schematic of the device is presented in Figure a. As the core component of an ultrasonic energy harvester (UEH) device, the anisotropic 1‐3 piezocomposite that combines the desirable performance of two different phases possesses better electromechanical coupling than the isotropic piezoelectric materials in ultrasonic energy transfer applications . The idea has proven to be effective in developing 1‐3 type piezocomposite composed of piezoelectric array and piezoelectric inactive polymer .…”

Materials and Structures toward Soft Electronics

“…When responding to the applied strain, the serpentine interconnections can rotate in plane and also buckle out of plane, resulting in greatly reduced strains in the serpentine material per se, as well as low effective stiffness on the system level . The serpentine patterns are typically fabricated by lithography‐based microfabrication, cut‐and‐paste manufacturing, and laser ablation . Metals are the most commonly used for the serpentine interconnections due to their excellent conductivity and low cost .…”

Flexible Sensors—From Materials to Applications

“…Perovskites can be divided into organic-inorganic halide perovskites following the structure ABX 3 (Figure 7a), where A is an organic cation, B is a metal cation and X is an halide anion, or inorganic only halides [272,273]. In flexible sensors, these materials have been mostly employed as active materials in photodetectors, prevalently in the form of organic-inorganic methilammonium lead bromide/iodide/chloride (CH 3 NH 3 PbX or MAPbX) [18,29,272,[274][275][276][277][278][279][280][281], and inorganic caesium lead bromide (CsPbBr 3 ) [282][283][284][285], or as piezoelectric materials such as PbZr x Ti 1-x O 3 (PZT) on ultrasound sensors [286]. The application and development of these materials for flexible optoelectronic applications has been widely researched due to their optical and electrical properties.…”

“…Ultrasonic transducers/sensors use high frequency sound waves which are vastly employed to perform non-destructive imaging of 3D objects in the free space by detecting reflected pulse-echo ultrasound signals. Air gaps formations and the extensive use of couplants at the subject interface contribute to the large acoustic distortions, energy reflections and transmission loss of the rigid probes [286]. In this sense, flexible electronics contributed to the realisation of stretchable transducers which solidly adhered to irregular and non-planar surfaces without requiring coupling agents, and resulting in an improvement of reliability of test results.…”