DETECTION METHOD FOR INTERNAL DEFECT AND ULTRASONIC MICROSCOPE FOR DETECTION OF INTERNAL DEFECT BY USING IT

摘要

PROBLEM TO BE SOLVED: To provide a detection method in which a contrast difference due to an internal defect is extracted by canceling the contrast difference of an image due to the scattering of ultrasonic waves overlapped with the image of an ultrasonic microscope and due to the flow of a medium.;SOLUTION: A received signal 12 is Fourier-transformed, and a power spectrum is found so as to be normalized by a center frequency f1. The power spectrum f2 of a frequency used to decide the distance between the focus of a lens and the surface of a sample is found in the whole scanning range so as to be changed into a two-dimensional image 31 while a relative value is used as a luminance difference. Thereby, a frequency dependence portion due to the scattering of the ultrasonic waves is canceled, an amplitude difference in a V (z) curve is changed into an image, the internal defect is expressed as the contrast difference, and the internal defect is detected easily.;COPYRIGHT: (C)2002,JPO