Patent ID: 8994958
Filing Date: 2015-03-31
Classification: G01D

Abstract:
1. An optical position measuring instrument for detecting a relative position of a scale and a scanning plate, the optical position measuring instrument comprising: a scanning plate; a scale, wherein said scale and said scanning plate are movable relative to one another in a measuring direction; a grating that is assigned to either said scanning plate or said scale; a light source that emits a beam toward said grating, wherein said grating receives said beam and splits said beam into two partial beams, whose polarization states are oriented orthogonally to one another, a polarizer being integrated either in said scanning plate or in said scale and being arranged in beam paths of said two partial beams, wherein said polarizer comprises a structure to generate polarization effects on said two partial beams striking said polarizer that are periodically variable along degrees of freedom of motion of said scale, wherein a polarization period of said periodically variable polarization effects is greater than a graduation period of said grating; said two partial beams being reunified into a resultant beam after further interaction with said scanning plate or with said scale; and a detection unit that receives said resultant beam and generates a plurality of displacement-dependent scanning signals.