| 摘要 |
PURPOSE:To detect defect only, by separating such defects as surface mirco- roughnesses from dust, etc. of an optically transparent specimen (object of inspection). CONSTITUTION:In a microscope equipped with illuminating A and testing optical systems B, C, out of No.1 and No.2 filters, 2 and 3 respectively, provided with mutually separatable frequency characteristics, the filter 2 is arranged near the optical axis center of the system A and the filter 3 on the periphery of the filter 2 respectively, and upon observation of a transparent specimen 6, surface micro-roughnesses on itself is observed by the system B only and such foreign substances as dust, etc. sticking onto the specimen 6 are detected by both optical systems B and C. Consequently, combination of an image developed by such optical system B using a mirror and an image obtainable by the system C, by the reason of the approximate complementary color relationship of No.3 filter 10 and No.4 filter 11, only the roughnesses of the specimen itself 6 can be observed in red color on the dark matrix. Namely, the micro-unevennesses of the specimen itself only can be detected without detecting such foreign substances as dust, etc. sticking simply on the specimen 6. |
