Inventors:
Ralph S. Hafle - Benton AR
Assignee:
BEI Electronics, Inc. - Little Rock AR
International Classification:
G02B 514
Abstract:
A multidigit fiber optic encoder having only one or two fiber optic cables between an active zone containing a light source and photodetectors, and a passive zone containing a multidigit code member having a multitude of code tracks. First and second sets of color filters are associated with the code tracks and the photodetectors, so that each code track modulates light of a different color, which is transmitted to only the corresponding photodetector. The light beams of the different colors are combined for transmission between the passive and active zones. A single fiber optic cable may be employed between the active and passive zones for transmitting light in both directions, by providing first and second beam splitters at the active and passive ends of the cable to split the transmitted and received light. Alternatively, two fiber optic cables may be employed to transmit light in the opposite directions, to obviate any need for the beam splitters. The light source provides white light or light containing multiple spectral lines, for illuminating all of the code tracks.