Thin-film acoustic imaging system for imaging through an exterior surface of an electronic device housing

An acoustic imaging system configured to adhere to an interior surface of a portable electronic device, the acoustic imaging system comprising:

• an adhesive layer configured to acoustically couple to the interior surface;
• a high acoustic impedance stack comprising:
• an actuator layer comprising an array of piezoelectric actuators formed below the adhesive layer;
• an array of electrode pairs, each associated with a respective piezoelectric actuator of the actuator layer, each electrode pair comprising:
• a first electrode disposed between the adhesive layer a top surface of the respective piezoelectric actuator;
• and
• a second electrode disposed on a bottom surface of the respective piezoelectric actuator opposite and parallel to the first electrode;
• and
• a metalloid oxide layer encapsulating the array of electrode pairs against a second surface of the actuator layer;
• and
• an application-specific integrated circuit formed below and coupled to the metalloid oxide layer of the high acoustic impedance stack, the application-specific integrated circuit conductively coupled to the array of electrode pairs.

An electronic device comprising an acoustic imaging system, the electronic device comprising:

• a housing;
• and
• the acoustic imagining system comprising:
• an adhesive layer configured to acoustically couple to an internal surface of the housing, thereby defining a portion of an external surface of the housing opposite the internal surface as an imaging surface;
• a first electrode layer bonded to the adhesive layer;
• a piezoelectric actuator layer below the first electrode layer;
• a second electrode layer below the piezoelectric actuator layer aligned with the first electrode layer to generate an electric field through the piezoelectric actuator layer;
• a metalloid oxide layer encapsulating the second electrode against the piezoelectric actuator layer;
• and
• an application-specific integrated circuit formed below and coupled to the metalloid oxide layer, the application-specific integrated circuit conductively coupled to the first electrode layer and the second electrode layer and configured to:
• apply a first voltage signal between the first electrode layer and the second electrode layer to cause an acoustic pulse to be generated by the piezoelectric actuator layer, the acoustic pulse propagating toward the imaging surface through the housing;
• and
• receive a second voltage signal from at least one of the first electrode layer or the second electrode layer after generating the acoustic pulse.