Optical motion encoder with a reflective member allowing the light source and sensor to be on the same side

摘要

An optical motion encoder for translation of movement information into a digital output. The optical encoder includes an optical member having a parabolic reflecting surface and a planar surface with a code pattern printed thereon. The light rays received by the parabolic reflecting surface from a light source positioned on the axis of symmetry of the parabolic reflecting surface are reflected as parallel light rays through the planar surface to be modulated by the code pattern and detected by a light detector. In this way, both, the collimator and the code wheel or code strip of prior art optical encoders are represented by a single optical member.