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:
Oct. 26, 1993
Filed:
Jun. 15, 1992
Karl A Stetson, Coventry, CT (US);
United Technologies Corporation, Hartford, CT (US);
Abstract
An optical head for a shearography system includes any standard TV camera lens 56, such as a wide-angle lens, which views a region of a test object 50 that is illuminated by coherent light 52. The lens 56 creates an image at an image plane where a field lens 80 is located. The field lens 80 redirects the light so as to allow substantially all the light of the image to pass through a first relay lens 86, thereby projecting the image with uniform brightness, i.e, no vignetting. The lens 86 provides collimated light 88,90 to a shearing element, such as a Michelson interferometer, comprising a beamsplitter 92 and two mirrors 94,96. Use of collimated light minimizes aberrations typically caused by beamsplitters. Collimated output light 102,104 from the shearing element is refocused onto a TV camera sensor plate 112 where the sheared interfered image is electronically detected for processing and viewing. The invention allows the shearing element to be sized independent of the size of the region on the object 50 to be imaged.