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:
Aug. 10, 1993
Filed:
Feb. 13, 1985
Applicant:
Inventors:
Hillary G Sillitto, Edinburgh, GB;
John C Parker, Edinburgh, GB;
Assignee:
GEC Ferranti Defence Systems Limited, Stanmore, GB;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01B / ; G01B / ;
U.S. Cl.
CPC ...
356354 ; 356352 ; 356346 ; 356374 ;
Abstract
Detector apparatus includes a dispersive prism (10) and a diffraction grating (11) of the type which produces only zero and first order diffraction patterns. Located behind the diffraction grating (11) so as to interact with the first harmonic content of the diffraction patterns is a Moire grating (12) having half the pitch of the diffraction grating (11). Detector means including at least two pairs of detectors (13-16) is located behind the Moire grating (12) to detect the presence of Moire fringes.