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. 01, 1981
Filed:
Aug. 11, 1980
Kent E Erickson, Brookside, NJ (US);
Keuffel & Esser Company, Morristown, NJ (US);
Abstract
An electro-optical measuring system in a photogrammetric comparator or stereocompiler comprises a visible light transparent phase grating which is carried upon a surface of the photo support plate of the device. The grating is formed as a composite layer of .lambda./4 films of at least two dielectric materials of different refractive index which are deposited on the support in such a manner as to yield parallel bands in which the two film materials are in alternating sequence from band to band. As a result of this structure which ensures a constant physical and optical thickness with respect to transmitted imaging light over the whole granting pattern, image-degrading diffraction of the transmitted visible light is avoided, yet the grating pattern provides interfering diffraction in reflection which may be utilized in a precise displacement measuring system.