Patent ID: 6861659
Filing Date: 2005-03-01
Classification: G01N

Abstract:
1. A method for inspecting an ununiformity of a transparent material by introducing a laser beam therein; wherein said transparent material comprises at least one pair of total reflective surfaces arranged so as to face each other in such a manner that the laser beam propagates along said pair of total reflective surfaces with being repeatedly and totally reflected therebetween, at least one pair of turning surfaces arranges so as to face each other in such a manner that the laser beam is turned back when the laser beam is impinged thereagainst, and an introductory surface for introducing the laser beam into said transparent material disposed in a manner to be sandwiched therebetween by at least one of said total reflective surfaces and at least one of said turning surfaces; said total reflective surfaces, said turning surfaces and said introductory surface being mirror-polished; and wherein when an optical path in said transparent material is uniform, the laser beam is introduced in such a manner that the laser beam which propagates in the transparent material and impinged on said total reflective surfaces and said turning surfaces totally reflects, and in an inspecting region of the transparent material sandwiched by one certain pair of said total reflective surfaces and one certain pair of said turning surfaces, one certain plane in said inspecting region filled with the laser beam by propagating the laser beam in said transparent material is relatively moved in the direction in which the inspecting region is filled with the laser beam for said transparent material; and when an ununiform portion exists in the optical path of the laser beam which is introduced and propagated in said transparent material, light which leaks out of said total reflective surface and/or said returning surfaces is detected, thereby inspecting the ununiformity of the transparent material.