Optical position-measuring device having grating fields with different step heights

An optical position-measuring device, comprising:

• a scale and a scanning reticle, whose relative position is determinable in three linearly independent spatial directions using a plurality of interfering light beams, two of the spatial directions being parallel to a plane of the scale and parallel to a plane of the scanning reticle, and the other one of the spatial directions having a component being perpendicular thereto;
• a splitter grating disposed on the scanning reticle and adapted to split light into a plurality of sub-beams of different diffraction orders;
• an optical grating disposed on the scale and adapted to further split the sub-beams and to recombine the further split sub-beams after the further split sub-beams have been reflected back from the scanning reticle;
• a plurality of grating fields configured as phase gratings disposed on a side of the scanning reticle that faces the scale, the grating fields acting as diffractive optics that influence the further split sub-beams, each of the grating fields comprising a plurality of graduation periods and a same step height, the step heights of the grating fields being different from each other;
• and
• an output grating disposed on the scanning reticle and adapted to output, as interfering sub-beams, light that has been multiply reflected between the scale and the scanning reticle.