Single photon avalanche diodes for rotational and translational input detection

An input component for a portable electronic device, comprising:

• a movable input member comprising a surface;
• a pattern defined on the surface;
• a light emitting element oriented to emit light toward the pattern such that the movable input member reflects the emitted light as reflected light;
• and
• an imaging system oriented to receive the reflected light and comprising:
• an array of single-photon avalanche diodes (SPAD) configured to operate in Geiger mode;
• and
• a counter circuit coupled to at least one SPAD of the array of SPADs, the counter circuit configured to iterate a value in response to an output of the at least one SPAD, the value:
• informing a determination of spatial phase of the reflected light;
• and
• the spatial phase corresponding to a movement of the movable input member.

An input component for a portable electronic device, the input component comprising:

• a movable input member comprising a surface on which is defined a pattern;
• a light emitting element oriented to emit light toward the pattern such that the pattern on the movable input member reflects the emitted light as reflected light;
• an array of single-photon avalanche diodes (SPAD) biased to at least breakdown voltage;
• and
• a circuit conductively coupled to the array of SPADs and configured to determine a spatial phase of the reflected light relative to the array of SPADs.