| 摘要 |
PURPOSE:To detect stably a true defective part by irradiating a lighting light from various directions to a position for detecting a sample while using a diffused lighting and eliminating the directivity so as to eliminate the interference due to minute ruggedness on the surface. CONSTITUTION:A diffused plate 34 such as frosted glass is provided in front of a lighting lamp 27 so as to eliminate the directivity of the lighting light 31, and the lighting light 31 is irradiated from various directions onto a coating film 12 including stain 16, crater 17 and foreign matter 18 so as to prevent interference due to the minute ruggedness on the surface of the sample. Then the light is scanned on the coating film 12 in the direction (x) and the reflected light 32 from the face of sample is subjected to photoelectric conversion by a photoelectric converting element 30 via an image forming lens 28 and a pin hole 29. Thus, the effect of minute ruggedness is not given to a voltage waveform of a detection signal 33 of the face of sample and a defect such as the stain 16, the crater 17 and the foreign matter 18 is indicated by voltage changes 16b, 17b, 18b and they are detected easily.
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