Optical encoder with direction-dependent optical properties having an optically anisotropic region to produce a first and a second light distribution

A portable electronic device comprising:

• a housing;
• a display positioned within an opening of the housing;
• a crown positioned on the housing and configured to receive rotational input;
• an optical encoder operatively coupled to the crown and configured to measure the rotational input, the optical encoder comprising:
• a spindle;
• an array of alternating regions formed on and extending along a length of the spindle;
• and
• an optical sensor configured to detect light reflected from the spindle and comprising:
• an optical emitter;
• an optical detector;
• and
• an optically diffusing member positioned adjacent a face of at least one of the optical emitter or the optical detector and configured to produce a light distribution that is wider in a direction along the length of the spindle.

An optical encoder for an electronic device, the optical encoder comprising:

• a spindle;
• an optical emitter configured to illuminate a portion of the spindle;
• an optical detector configured to receive light from the illuminated portion of the spindle;
• and
• an array of features arranged along a length the spindle;
• wherein the array of features is configured to:
• produce alternating light and dark reflections on the optical detector;
• produce a first type of reflection having a first beam spread for light along a transverse plane that is perpendicular to a central axis of the spindle;
• and
• produce a second type of reflection having a second beam spread for light along a longitudinal plane that passes through the central axis of the spindle, wherein the second beam spread is wider than the first beam spread.