Hunton Andrews Kurth LLP
Position-measuring device
In a position-measuring device for determining the position of a first object with respect to a second object that is displaceable relative to the first object, a measuring standard is connected to the first object and includes at least one periodic scale grating, which is arranged as a transmission grating and has a first periodicity. A scanning unit is connected to the second object and includes at least one light source, at least one periodic scanning grating, which has a second periodicity, and a detector system, which includes detector regions that are sensitive to radiation and are periodically disposed at a third periodicity in a detection plane. The bundles of rays emitted by the light source first impinge upon the scale grating and then pass through the scanning grating. The interaction of the bundles of beams with the scale grating and the scanning grating produces a periodic fringe pattern having the third periodicity in the detection plane which, when scanned with the aid of the detector system, makes it possible to generate a plurality of incremental signals that are phase-shifted relative to one another. The scanning grating is arranged between at least one first and one second transparent, plate-shaped carrier element, and the space between the scanning grating and the detector regions is completely filled with a material that has a refractive index of n>1.3. The clearance between the scale grating and the adjacent boundary surface of the first carrier element is in the range of 10 μm to 200 μm.
DR. JOHANNES HEIDENHAIN GMBH
G G G
G01D G01D G01D
inventional inventional inventional
Christoph Johannes Wolfgang
Lingk Trautner Holzapfel