Dr. Johannas Heidenhain Gmbh

Walburga Kern

Peter Speckbacher

Georg Flatscher

Anton Sailer

Michael Allg&auml;uer

In a position measuring device, a scale is embodied as a phase grating on which several partial beams impinge and are diffracted and caused to interfere with each other in the scanning unit. The entry angle (&agr;) of the partial beams corresponds to the Littrow angle, so that the diffracted partial beams of &plusmn;1st diffraction order are diffracted at the same angle &bgr;&equals;&agr;. The diffraction efficiency of the scale is particularly great if the flanks of the bars of the scales are at an angle of approximately 70&deg; with respect to the measuring direction, i.e., if the bars and gaps are embodied to be trapezoidal in cross section.

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Traunreut, Germany

Walburga Kern