Polarization-based crosstalk mitigation in optical ranging sensors

A method for determining a proximity of a target at an optical ranging sensor, the method comprising:

• causing an optical transmitter to transmit a first signal having a first polarization state;
• receiving from an optical receiver a first feedback signal resulting from one or more reflections of the first signal;
• causing the optical transmitter to transmit a second signal having a second polarization state;
• receiving from the optical receiver a second feedback signal resulting from one or more reflections of the second signal;
• generating a target feedback signal based on a comparison of the first feedback signal and the second feedback signal;
• and
• determining the proximity of the target based on the target feedback signal.

A mobile electronic device comprising:

• a housing;
• a display screen attached to the housing, the display screen comprising:
• a first side configured to emit transmitted light via a plurality of display pixels into an external environment;
• and
• an optical ranging sensor disposed within the housing, opposite the first side of the display screen, the optical ranging sensor comprising:
• an optical transmitter configured to generate a first signal having a first polarization state and a second signal having a second polarization state;
• an optical receiver configured to receive:
• a first feedback signal resulting from one or more reflections of the first signal;
• and
• a second feedback signal resulting from one or more reflections of the second signal;
• and
• a controller configured to:
• generate a target feedback signal based on a comparison of the first feedback signal and the second feedback signal;
• and
• determine a proximity of a target based on the target feedback signal.