DEVICE INCLUDING AN ULTRASONIC FINGERPRINT SENSOR AND A COULOMB FORCE APPARATUS

An apparatus may include an ultrasonic sensor system, a Coulomb force apparatus and a control system. The control system may be configured for controlling the Coulomb force apparatus for application of a Coulomb force to a digit in contact with an outer surface of the apparatus in a fingerprint sensor area and for controlling the ultrasonic fingerprint sensor for transmission of first ultrasonic waves towards the digit. The control system may be configured for synchronizing the application of the Coulomb force and the transmission of the first ultrasonic waves. The control system may be configured for receiving ultrasonic receiver signals from the ultrasonic fingerprint sensor and for performing an authentication process based, at least in part, on the ultrasonic receiver signals. The ultrasonic receiver signals may, in some instances, include signals corresponding to reflections of the first ultrasonic waves from the digit.