A touch sensing system including an ultrasonic transmitter and a force-sensing device , the force-sensing device comprising: a substrate ; an array of sensor pixel circuits disposed on the substrate ; discrete elements of a piezoelectric film layer , each discrete element corresponding with an individual sensor pixel circuit; a plurality of pixel input electrodes , each pixel input electrode configured for making an electrical connection between a first side of a discrete element of the piezoelectric layer and one of the sensor pixel circuits; a receiver bias electrode configured for making an electrical connection with a second side of discrete elements of the piezoelectric layer; and a control system configured to: receive a signal from one or more of the sensor pixel circuits , the signal corresponding to a force applied to one or more discrete elements of the piezoelectric film layer ; and determine a location of an object exerting the force when the control system is configured to operate the touch sensing system in a force-sensing mode, wherein the control system is further configured to operate the touch sensing system in an ultrasonic imaging mode or the force-sensing mode; and maintain the ultrasonic transmitter in an "off" state when operating the touch sensing system in the force-sensing mode, wherein in the ultrasonic imaging mode, the ultrasonic transmitter is in an "on" state, and the force-sensing device is configured to function as an ultrasonic receiver. a substrate ; an array of sensor pixel circuits disposed on the substrate ; discrete elements of a piezoelectric film layer , each discrete element corresponding with an individual sensor pixel circuit; a plurality of pixel input electrodes , each pixel input electrode configured for making an electrical connection between a first side of a discrete element of the piezoelectric layer and one of the sensor pixel circuits; a receiver bias electrode configured for making an electrical connection with a second side of discrete elements of the piezoelectric layer; and a control system configured to: receive a signal from one or more of the sensor pixel circuits , the signal corresponding to a force applied to one or more discrete elements of the piezoelectric film layer ; and determine a location of an object exerting the force when the control system is configured to operate the touch sensing system in a force-sensing mode, wherein the control system is further configured to operate the touch sensing system in an ultrasonic imaging mode or the force-sensing mode; and maintain the ultrasonic transmitter in an "off" state when operating the touch sensing system in the force-sensing mode, wherein in the ultrasonic imaging mode, the ultrasonic transmitter is in an "on" state, and the force-sensing device is configured to function as an ultrasonic receiver. receive a signal from one or more of the sensor pixel circuits , the signal corresponding to a force applied to one or more discrete elements of the piezoelectric film layer ; and determine a location of an object exerting the force when the control system is configured to operate the touch sensing system in a force-sensing mode, wherein the control system is further configured to operate the touch sensing system in an ultrasonic imaging mode or the force-sensing mode; and maintain the ultrasonic transmitter in an "off" state when operating the touch sensing system in the force-sensing mode, wherein in the ultrasonic imaging mode, the ultrasonic transmitter is in an "on" state, and the force-sensing device is configured to function as an ultrasonic receiver. <EOS>