| 摘要 |
<p>PURPOSE:To detect the relative positions of a mask pattern and a foreign matter by a method wherein a dark vision illuminator and a transmitting illuminator are provided respectively on the main surface side and the backside of a product while an optical examination system which can simultaneously examine a transmitted image and dark vision is provided on the main surface side of product. CONSTITUTION:A dark vision illuminator 4 composed of a light source 2 and a lens 3 is arranged on the main surface side of mask 1 while a transmitting illuminator 7 composed of another light source 5 and another lens 6 is also arranged on the backside of mask 1. Besides, an optical examination system 10 composed of the other lens 8 and a television camera 9 is provided on the main surface side of mask 1. An image is formed of an image of pattern 13 illuminated as a black pattern by a transmitted image 12, a foreign matter 14 by a dark vision image 11 and a bright image of another foreign matter 15. In such a constitution, the dark vision image 11 and the transmitted image 12 can be visualized simultaneously in the same vision so that the relative positions of mask pattern and foreign matters may be detected accurately without fail.</p> |
