Optical absolute encoder for measuring angular increments - uses image information mask cooperating with CCD sensor or LED array

摘要

The optical absolute encoder has a round image mask directly applied to a rotating carrier, with constant diffuse illumination of the mask in LED's. The image information is evaluated via a CCD sensor receiving light reflected from the surface of the disc. Alternatively the mask is transparent with a concave lens behind the mask for reflection of light onto a photodiode array.