Abstract

Micromachined ultrasonic transducers (MUTs) are best known for their use in medical imaging, a field where imaging performance dominates over features such as transducer size, weight, power consumption and cost. In comparison, these features are the main drivers for the success of MEMS in consumer electronics and automotive applications, such as pressure sensors, accelerometers, gyroscopes, and microphones. These MEMS sensors replaced their conventional counterparts and enabled novel and unexpected applications where low cost, small size, light weight, and ultra-low power consumption are critical. In this talk, I describe ultrasonic sensors based on piezoelectric MUTs (PMUTs) intended for consumer electronics applications such as range-finding and fingerprint sensing. A common characteristic of these applications is that they require manufacturing at high volume with relatively low cost. We have developed air-coupled ultrasonic sensors based on PMUTs that operate at 10 microwatts. Relative to optical sensors, these ultrasonic sensors have the advantage of very low power consumption and long range. In related research, we demonstrated a 500 DPI ultrasonic fingerprint sensor that has similar resolution to Apple’s TouchID sensor but the added advantages that it is capable of imaging wet or oily fingers and can image the dermis beneath the surface of the finger.