Piezoelectric film structures and sensors and display assemblies using same

A piezoelectric film sensor having touch-sensing capability in response to a touch event at a touch location, comprising:

• first and second transparent conducting layers that define first and second electrodes;
• at least one transparent piezoelectric layer interposed between the first and second electrodes;
• wherein the first electrode, the second electrode and the at least one transparent piezoelectric layer are configured to provide touch-location functionality and to generate an output signal in response to the touch event;
• a first transparent optical layer disposed on and in contact with the first electrode and a second transparent optical layer disposed on and in contact with the second electrode, with the first transparent optical layer defining an uppermost surface, wherein the first electrode is between the substrate and the first optical layer and the second electrode is between the substrate and the second optical layer, and further wherein the first electrode and the second electrode are opposite the piezoelectric layer;
• a substrate disposed adjacent the second optical layer wherein the second optical layer is disposed on and in contact with the substrate;
• and
• a signal processing system electrically connected to the bottom and top transparent conducting layers and configured to process the output signal to determine at least one touch-sensing feature associated with the at least one touch event,
• wherein each of the first and second transparent optical layer includes at least one material selected from the group of materials comprising:
• SiNx, SiOxNy, AlNx, AlOxNy, SiAlxOyNz, SiO2, SiOx, Al2O3, and AlOx.

A method of providing piezoelectric touch sensing for a device having a user interface, comprising:

• interfacing a piezoelectric film sensor having touch-sensing capability with the device so that the user interface can be viewed through a transparent piezoelectric touch-sensing (PETS) piezoelectric film structure of the piezoelectric film sensor;
• causing a touch event by touching a surface of the piezoelectric film sensor at a touch location that corresponds to a location of the user interface, thereby causing the PETS piezoelectric film structure to generate an output signal;
• and
• processing the output signal to determine at least one touch-sensing feature associated with the touch event,
• wherein the PETS piezoelectric film structure comprises a top and bottom transparent optical layer and a top and bottom electrode,
• wherein the bottom transparent optical layer is disposed on and in contact with a substrate and the bottom electrode is disposed on and in contact with the bottom transparent optical layer, and
• further wherein each of the top and bottom optical layer includes at least one material selected from the group of materials comprising:
• SiNx, SiOxNy, AlNx, AlOxNy, SiAlxOyNz, SiO2, SiOx, Al2O3, and AlOx.