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:
May. 24, 1988
Filed:
Oct. 01, 1986
Jan G Dil, Almelo, NL;
U.S. Philips Corp., New York, NY (US);
Abstract
Displacement of an object is sensed by a transducer element having light first strips and dark second strips alternating in a direction of object displacement. The first strips are formed as phase gratings having grating lines extending in the direction of displacement and having a width equal to half the grating period and a depth such that the zero-order diffraction beam is suppressed. The lines may be grooves or ribs, separated by lands which are at the same level as the second strips. A device, for measuring displacement of an object on which such an element is fixed, includes an imaging system having an aperture limited such that first and higher-order diffraction beams from the phase grating are not transmitted to a radiation-sensitive pattern detection system.