| 摘要 |
PURPOSE:To discriminate the flaw of a transparent body between front and rear surfaces and between sorts, by a method wherein rays parallel to the front surface of the transparent body are projected separately on front, rear and end surfaces of the transparent body and rays of random reflection are detected. CONSTITUTION:A glass mask 1 is enclosed at bridging state in a dark box by supporting edge of the glass mask by a support member 14. The slit 19 of a movable slit member 18 is opposed to front surface of the mask 1. If light is projected by a light projector, parallel rays are projected on front surface of the mask 1 and random reflection is performed only at a foreign substance 1A on front surface of the mask 1. If the slit 19 is opposed to end surface of the mask 1, the parallel rays are entered into the mask 1 through the end surface. The rays produce random reflection only at flaw 1C, 1D formed at front and rear surfaces of the mask 1. If the slit 18 is opposed to rear surface of the mask 1, the parallel rays produce random reflection only at foreign substance 1B on rear surface of the mask 1. In this constitution, front and rear surfaces of the mask 1 are observed from inspection windows 13A and 13B thereby position and sort of flaw can be detected. |
