Patent ID: 9303981
Filing Date: 2016-04-05
CPC Classification: G01B,G01D

Claim Text:
1. A position-measuring device, comprising: a scale having a measuring graduation, at least one reference mark and area markings located on a first and on a second side of the at least one reference mark which are configured to exert different deflection effects on a scanning beam incident on the area markings, the measuring graduation being optically scannable such that periodic measurement signals are generatable by optically scanning the measuring graduation, the at least one reference mark being optically scannable such that a reference signal is generatable by optically scanning the reference mark and the area markings being optically scannable such that an area signal is generatable by optically scanning the area markings with the scanning beam, an area signal detector configured to detect, during optical scanning of the area markings, a fringe pattern in a detection plane of the area signal detector, a scanning unit movable relative to the scale in a measurement direction, the area signal being usable to distinguish whether the scanning unit is located on the first or on the second side of the reference mark, and a periodic screen grating disposed between the scale and the area signal detector and configured to produce the fringe pattern in the detection plane of the area signal detector such that at least two distinguishable scanning signals are generatable from the fringe pattern as a function of a position of the scanning unit relative to the at least one reference mark.