Patent ID: 8817272

Claim:
An optical position-measuring device for detecting a position of two objects movable relative to each other in at least one measuring direction, comprising: a measuring standard joined to one of the two objects and including an incremental graduation extending in the measuring direction and at least one reference marking at a reference position, the reference marking including two reference-marking subfields arranged in mirror symmetry with respect to a reference-marking axis of symmetry, each reference-marking subfield including a structure, extending in measuring direction, having a graduation period that changes locally; a scanning unit joined to the other of the two objects, a scanning device assigned to the scanning unit adapted to generate at least one reference signal at the reference position, the scanning device including: a light source adapted to emit light divergently in a direction of the measuring standard; and a detector system including elements disposed along the measuring direction such that, starting from a central detector-system axis of symmetry in the measuring direction, center-to-center distances between adjacent elements in a same direction change correspondingly to the graduation periods of the structures in the reference-marking subfields starting from the reference-marking axis of symmetry.