Patent ID: 8759746

Claim:
A rotary encoder, comprising: a light source module, disposed fixedly in the rotary encoder for emitting light; a code plate, disposed fixedly in the rotary encoder and optically coupled with the light source module, wherein the code plate has a plurality of light transmitting regions alternating with a plurality of light non-transmitting regions for forming an image with a plurality of bright stripes and a plurality of dark stripes by the light passing through the code plate; an optical wheel, comprising a wheel body having a rotation axis and a plurality of imaging elements disposed fixedly on the wheel body and arranged annularly around the rotation axis, wherein each of the imaging elements has a focal point, wherein the wheel body is pivotally disposed in the rotary encoder, and at least one of the imaging elements is optically coupled with the code plate for enlarging the image; and an optical sensor module, disposed fixedly in the rotary encoder and optically coupled with at least one of the imaging elements for being irradiated by one of the bright stripes of the enlarged image.