| 摘要 |
An apparatus for detecting the defects composed of non-linear components of a subject pattern, includes a laser source for illuminating the subject pattern by a laser beam, a Fourier-transform lens for projecting an information light from the pattern through a spatial filter onto a screen. The filter is placed on the Fourier-transform plane of the Fourier-transformed information light for intercepting the coherent light having information on linear components, the filter having arm sections extending correspondingly to the linear components of said normal pattern, the outer periphery of said arm sections including curved sections of a circular or elliptical shape protruding toward the intersecting point of the arms. |
