Fibre=optic encoder of position of rotating element - has concentric tracks on disc with alternately dark and bright regions reflecting light into fibre ends

摘要

A graduated disc (17) mounted on the rotating element (2) with its winding (4) faces an array of optical fibres (e.g. 10-12) which are connected at one end to a cylindrical support plate (9) opposite the disc. The other ends of the fibres are terminated in a compartment (6') contg. a light emitter and three phototransistors (e.g. 7, 8) coupled to the fibre ends through slits in a wall. The disc carries e.g. three concentric annular tracks, two of which have alternate regions of high and low reflectivity while the third track has an indexing region. USE/ADVANTAGE - E.g. for rotary DC motor, encoder is compact with high resolution. Different tracks give precise phase differences and half-periods of signals are equal.