Position-measuring device

摘要

A position-measuring device includes: a measuring graduation provided on a material measure going around in ring-like fashion; a scanning unit for optically scanning the measuring graduation using electromagnetic radiation; a scanning plate with a periodic scanning graduation which is arranged in the beam path of the electromagnetic radiation used for scanning the measuring graduation, so that the radiation interacts both with the scanning graduation and with the measuring graduation; and a detector of the scanning unit, the detector surface of which is used for detecting the electromagnetic radiation after interaction with the scanning graduation and the measuring graduation and which is arranged with a period (PD) for detecting electromagnetic radiation in the form of a stripe pattern. The period PM of the measuring graduation and the period PA of the scanning graduation may be coordinated so that 1/(1/PA-1/PM)<PD.