Patent ID: 6226079
Filing Date: 2001-05-01
Classification: G01N

Abstract:
An apparatus for assessing any defect within a solid by irradiating the surface of the solid with light rays of a plurality of wavelengths and detecting scattered light from any defect at least in that solid, provided with:irradiating optical systems for irradiating with light rays of at least two different wavelengths differing in the depth of penetration into said solid;a detecting optical system for detecting the intensity of scattered light from a defect generated by a shorter wavelength one of the light rays of at least two different wavelengths emitted from the irradiating optical systems, and that of scattered light from the defect generated by a longer wavelength one of same;a calculating means for figuring out, from the scattered light intensity deriving from said shorter wavelength ray and that deriving from said longer wavelength ray, both detected by said detecting optical system, a value corresponding to a defect size and another value corresponding to a defect depth; anda display means for displaying a distribution revealing the relationship between said defect size and said defect depth and wherein the detectable depth in said distribution depends on said defect size.