will be understood to those of ordinary skill in the art the plate through holes 34 may connect via conductive traces 36 in multiple layers of the printed circuit board 32 to integrated circuits 40 attached to the rear surface of the printed circuit board 32 the integrated circuits 40 provide input signal processing such as multiplexing and amplification as will be described referring now to fig3 in the preferred embodiment for use in a ultrasonic imaging machine 38 the controller 50 operating in a transmission mode activates a signal generator 54 to provide a high voltage electrical signal applied through a switch 59 to the electrode 29 to stimulate the piezoelectric film 12 the signal generator 54 may for example provide a 500 khz wide band pulse referenced to a fixed crystal oscillator the switch 59 is a solid state switch controlled by the controller 50 to alternately connect the electrode 29 to either the signal generator 54 or to ground or a functionally similar source of constant voltage alternatively multiple generators could be used to generate focused or otherwise controlled transmit waves contact with electrode s 29 may be made through thin wires or flexible circuit elements passing from the circuit card to the front face of the piezoelectric film 12 the voltage of the signal generator 54 when applied with respect to the virtual ground of the backer electrodes 30 produces a transmitted ultrasonic signal 60 when so energized the piezoelectric film 12 will direct the transmitted ultrasonic signal 60 generally along a longitudinal axis 15 perpendicular to the front face 18 of the piezoelectric film 12.