Piezo based force sensing

A system comprising:

• a first piezoelectric layer;
• a second piezoelectric layer coupled to the first piezoelectric layer;
• a cover coupled to the second piezoelectric layer by a first layer of adhesive;
• a first electrode layer coupled to the first piezoelectric layer and disposed in a first linear pattern;
• a second electrode layer coupled between the first and second piezoelectric layers disposed in a grid pattern;
• a third electrode layer coupled between the second piezoelectric layer and the cover, and disposed in a second linear pattern oriented perpendicular to the first linear pattern;
• and
• a sense circuitry operable to detect an electric charge generated by the first and second piezoelectric layers in response to a deformation of the first and second piezoelectric layers and determine a magnitude and a location of an exerted force based on the electric charge.

A system comprising:

• a piezoelectric layer;
• a touch sensor coupled to the piezoelectric layer by a first layer of adhesive;
• a cover coupled to the piezoelectric layer by a second layer of adhesive;
• a first electrode layer coupled to the piezoelectric layer and disposed in a first linear pattern;
• a second electrode layer coupled between the piezoelectric layer and the touch sensor and disposed in a second linear pattern perpendicular to the first linear pattern;
• and
• sense circuitry operable to detect an electric charge generated by the piezoelectric layer in response to a deformation of the piezoelectric layer and output an estimated magnitude of force exerted on the cover based on the electric charge.