Patent ID: 9595447
Date: 2017-03-14
CPC Classifications: G03F,G06K,G06T,H01L

Claim:
1. A detection apparatus configured to detect a moire pattern generated by grid patterns having grid pitches different from each other, the detection apparatus comprising: an image-pickup unit configured to pick up an image of the moire pattern; an imaging optical system configured to form the image of the moire pattern on the image-pickup unit; a processing unit configured to process an image-pickup result of the moire pattern picked up by the image-pickup unit; and a reference mark, disposed on a member, which has a plurality of pattern elements periodically arranged in a first direction, wherein none of the pattern elements have widths larger than a resolving power of the imaging optical system in the first direction, wherein the widths of the pattern elements and intervals between the pattern elements in the first direction vary in the first direction, wherein the reference mark is different from the grid patterns and is for evaluating the detection apparatus by an image of the reference mark alone, wherein the imaging optical system picks up the image of the reference mark alone.