Patent ID: 9140537
Filing Date: 2015-09-22
Classification: G01B,G01D,G03F

Abstract:
1. An encoder interferometry system comprising: a beam splitting element positioned to receive an input beam from a light source, wherein the beam splitting element is configured to direct a first portion of the input beam along a measurement path to define a measurement beam and a second portion of the input beam along a reference path to define a reference beam; an encoder scale positioned to diffract the measurement beam at least once; one or more optical components configured and arranged to alter a direction of a first diffracted portion of the measurement beam and a direction of a second diffracted portion of the measurement beam such that beam paths of the first diffracted portion and the second diffracted portion are non-parallel subsequent to the first diffracted portion and the second diffracted portion passing through the beam splitting element; and a detector positioned to receive the first diffracted portion of the measurement beam.