Multifunctional high-density ultrasonic microsensor for ranging and 2D imaging

Ultrasound has been implemented as a powerful tool for noninvasive imaging and non-contact ranging. However, the size and single-function of traditional ultrasonic probes have limited their adaptability to complex application scenarios in the artificial intelligence era. This paper reports a multifunctional microsensor based on a piezoelectric micromachined ultrasonic transducer (pMUT) array that can be used for ranging and 2D imaging at the same time, in air, with a small working size (2 × 0.8 mm2) and low driving voltage (10 V). A back-end circuit was also designed to optimize the performance of the pMUT array, resulting in a peak-to-peak value of 158 mV. The characterization of the multifunctional microsensor demonstrated that it is capable of performing ranging and 2D imaging simultaneously with high spatial resolution (∼1 mm in ranging and ∼0.2 × 0.2 mm2 in 2D-imaging), even in complex application scenarios. This paper describes a system that integrates micro-electro-mechanical systems device, back-end circuit, imaging algorithm, and denoising algorithm, which allow the microsensor to provide multiple functions. This makes it a promising tool for a wide range of human–machine interaction applications, such as gesture recognition, robotics, and healthcare.