Shukushotoeirokosochi

摘要

PURPOSE:To make possible the direct detection of a reduction projected image by providing an enlargement optical system for enlarging a pattern for evaluation and the reduction projected image formed on the pattern and a detection system. CONSTITUTION:The reduction projected image formed by a reduction projecting lens 1 is projected onto the pattern 12 for evaluation and the optical image is formed on a color TV camera 7. The image 13 of the pattern 12 and the reduction projected image 14 are projected and the relation between the position on XX' and the quantity of light is determined by such images. Focusing and the calibration of a pattern detector are made possible by the signals thereof. More specifically the best focus point is determined by adjusting a lens barrel system or stage 3 in the optical axis direction of the lens 1 in such a manner that the shape of an edge 16 by the image 14 is most approximate to the shape of an edge 15 by the image 13. The centroid position of the image 14 and the centroid position of the pattern 13 are determined by the signal processing and further the position of the image 14 including the set error quantity of the base 3 is calculated.