Patent ID: 11946782
Assignee: DR. JOHANNES HEIDENHAIN GMBH
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 12:
13. An arrangement, comprising:
a plurality of optical position-measuring devices, each of the optical position-measuring devices comprising:
a light source configured to emit an illumination beam along a scanning beam path; and
at least two scales, which are movable relative to each other along at least two measurement directions and disposed in different planes in crossed relation to each other, the at least two scales each having at least one measuring graduation having grating regions which are arranged periodically along at least one of the measurement directions and have different optical properties, each of the at least two scales having a direction of longitudinal extent oriented parallel to a first or a second one of the measurement directions; and
a detector configured to generate one or more position-dependent scanning signals with respect to relative movement of the scales along the first or second measurement direction,
wherein the scanning beam path is configured such that:
at the first scale, the illumination beam is split into at least two sub-beams,
the at least two sub-beams subsequently impinge on the second scale and are reflected back toward the first scale, and
the reflected-back sub-beams strike the first scale again, where the reflected-back sub-beams are recombined, so that at least one resulting signal beam subsequently propagates toward the detector, and
wherein the at least one measuring graduation of at least one of the scales is configured as a two-dimensional cross grating which has a filtering effect that suppresses disturbing higher diffraction orders at the cross grating; and

a stage disposed in a horizontal plane of movement in such a manner that the stage is movable along two orthogonal ones of the measurement directions,
wherein two of the first scales of two of the optical position-measuring devices are disposed at opposite sides of the stage,
wherein at least one of the second scales of at least one of the optical position-measuring devices is disposed crosswise at an angle of 90° and stationary with respect to the two first scales in a plane that is spaced apart from the horizontal plane of movement along a direction that is oriented orthogonally to the horizontal plane of movement, and
wherein each of the plurality of the optical position-measuring devices include a scanning unit, which includes the light source and the detector, the scanning units being disposed stationarily adjacent to the opposite sides of the stage with the respective first scales.