Fibre optic displacement sensor - has 3-way coupler and branching transfer fibre into reference and sensing fibres with lenses directing light onto movable mirror

摘要

A fibre optical displacement sensor contains a transfer fibre (9) branching via a 3-way coupler (11) into reference and sensor fibres (12,13) of different lengths in reference and sensing branches. Sensing and reference branch lenses (39,19) direct sensing and reference light beams onto a mirror (25) parallel to the sensing branch lens and movable perpendicularly wrt. its reflecting surface. The sensing branch lens produces a parallel beam whose axis is tilted wrt. the normal to the surface of the mirror illuminated by it. USE/ADVANTAGE - The fibre optic distance sensor exhibits great dynamic range with simultaneous short and long term stability.