Patent ID: 8890057

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 relative to a reference-marking axis of symmetry, each reference-marking subfield including a grating structure that extends in the measuring direction and has a locally changeable graduation period; and a scanning unit joined to the other one of the two objects and including a divergently emitting light source, at least one grating, and a reference-signal detector system; wherein the reference-signal detector system includes at least four detector arrays, each detector array including a plurality of detector elements; and wherein the detector arrays are adapted to form, from scanning of the reference marking via the reference-signal detector system, a first pair of partial reference signals and a second pair of partial reference signals, each having a signal pattern in phase opposition, the first pair of partial reference signals offset along the measuring direction by an offset amount relative to the second pair of partial reference signals.