Patent Document ID: 3964830
Application ID: 05455369
Patent Status: 1

Claim One:
1. A method for inspecting flaws in material, comprising the steps of: a. directing a parallel beam generated from a source of a coherent wave of light through a spherical lens; b. forming a cone-shaped coherent spherical wave of light by focusing said parallel beam to a focal point of said spherical lens; c. positioning said material in a manner to provide intersection of said cone-shaped coherent spherical wave of light and a region of said material at a predetermined distance from said focal point, said region of said material on which said cone-shaped coherent spherical wave of light impinges being substantially larger than the size of said flaws to be inspected; d. positioning an inspection screen at a predetermined distance from said material to intersect light reflected from said region in order that a Fresnel diffraction pattern of microflaws to be inspected becomes an observable size; and, e. observing said inspection screen with regard to whether or not said distribution of said light reflected from said region includes a Fresnel diffraction pattern of said microflaws thereby enabling detection of said microflaws within said region of said material to be inspected.