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:
Mar. 05, 1996
Filed:
Aug. 22, 1994
Paul F Sullivan, Westwood, MA (US);
Polaroid Corporation, Cambridge, MA (US);
Abstract
A preferred position detection system for accurate one-dimensional operation is realized using a diffractive encoder which provides two digital output signals 90.degree. out of phase. The two output signals correspond to relative movement between two objects. The diffractive encoder includes: a light source; a collimating lens; a mask; a diffractive grid; four photodetectors; and two comparators. Light from the light source is collimated through the collimating lens, selectively passed through the aperture in the mask, diffracted by the diffractive grid, sensed by the four photodetectors, then compared by the comparators to produce the two digital output signals which represent relative movement between the mask and the diffractive grid.