US Patent 9824254 Biometric sensing device with discrete ultrasonic transducers

A biometric sensing system includes discrete ultrasonic transducers, a first electrode layer disposed over a first surface of the discrete ultrasonic transducers, and a second electrode layer disposed over a second surface of the discrete ultrasonic transducers. The first electrode layer may be a sheet of conductive material that is a common ground connection for the discrete ultrasonic transducers. Alternatively, the first electrode layer can be formed with discrete electrode elements, with a discrete electrode element disposed over the first surface of a discrete ultrasonic transducer. The second electrode layer may be formed with discrete electrode elements, with a discrete electrode element disposed over the second surface of one ultrasonic transducer. At least one integrated circuit can be attached and connected to one of the electrode layers. The integrated circuit includes drive circuits and sense circuits for the discrete ultrasonic transducers.