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. 09, 1995
Filed:
Mar. 10, 1993
Ralph M Grant, Rochester, MI (US);
Forrest Wright, Rochester, MI (US);
Grant Engineering, Inc., Rochester, MI (US);
Abstract
A shearogram representing an object and including a fringe pattern arising from a change in local surface strain brought about by an applied stress during the making of the shearogram is reconstructed by a special viewer. The viewer holds the shearogram transparency adjacent to a focusing lens having an optical axis, and projects off-axis white light through the lens and transparency to a focal plane where the resulting diffraction pattern is viewed directly on a screen or by a video camera and display monitor. By projecting the light from different positions around the axis a first position can be found which tunes the diffraction efficiency to an optimum for the best view of fringe patterns and a second position can be found which eliminates the fringe patterns and shows only a photographic image of the object. The light source is a rotatable disk with two apertures containing light diffusing elements which are illuminated by a lamp. The disk is rotated to change the projection angle.