摘要 |
An incremental position encoder comprising a first member arranged for movement with a second member the movement of which is to be monitored, a plurality of light transmissive or reflective elements of three distinct colors, said elements being arranged in a row on said first member, and the elements being arranged in the row in a repeating sequence of said three colors, a light source directing light to said elements and a color sensitive light detector for receiving light transmitted by, or reflected from said elements, said color sensitive detector being arranged to produce, at any given instant, one of three distinct outputs dependant upon the color of the three available, of the element which is at that instant transmitting or reflecting light from the source to the detector.
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