Rotary optical encoder with rotating angle-encoding light pattern

A rotary optical position encoder, comprising:

• a source/detector assembly having a source and a detector, the source being configured and operative to produce a light beam, the detector being configured and operative to receive the light beam with a position-dependent pattern therein and produce one or more corresponding position-indicating detector output signals;
• and
• an optical element configured for rotation relative to the source and detector, the optical element including an angularly varying optically responsive pattern operative in response to the light beam from the source to produce the position-dependent pattern in the light beam for detection by the detector, the position-dependent pattern having a smoothly varying characteristic as a function of angle, corresponding to the angularly varying optically responsive pattern of the optical element, to emphasize a fundamental component of rotational position in the position-indicating detector output signals.