The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 03, 2002
Filed:
Dec. 16, 1997
Peter Speckbacher, Kirchweidach, DE;
Michael Allgäuer, Stein/Traun, DE;
Georg Flatscher, Schneizlreuth, DE;
Anton Sailer, Traunstein, DE;
Walburga Kern, Traunreut, DE;
Dr. Johannas Heidenhain GmbH, Traunreut, DE;
Abstract
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 ±1st diffraction order are diffracted at the same angle &bgr;=&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° with respect to the measuring direction, i.e., if the bars and gaps are embodied to be trapezoidal in cross section.