Patent ID: 6049204
Filing Date: 2000-04-11
Classification: G01B,G01D

Abstract:
An elongated linear scale, comprising:a slider assembly;an elongated scale having a measuring axis, the slider assembly movable along the measuring axis;at least one magnetic field generator, each magnetic field generator responsive to a drive signal to generate a first changing magnetic flux in a first flux region;at least one flux coupling loop, a first portion of the at least one flux coupling loop positionable within the first flux region and responsive to the first changing magnetic flux when positioned within the first flux region to produce a second changing magnetic flux in a second portion of the flux coupling loop in a second flux region that is separated from the first flux region; andat least one magnetic flux sensor;wherein:one of a) the at least one magnetic flux sensor or b) the at least one magnetic field generator includes an inductive area extending along the measuring axis, and the inductive area is spatially modulated along the measuring axis in a pattern including alternating increases and decreases in width,each magnetic flux sensor is positioned outside the first flux region to sense the second changing magnetic flux in the second flux region portion of at least one flux coupling loop, andeach magnetic flux sensor is responsive to the second changing magnetic flux to generate an output signal which is a function of the relative position between the slide and the elongated scale.