Patent ID: 7755771

Claim:
A pitch measurement method of performing noncontact measurement of a distance between target points of adjacent shape-of-interest portions, which defines a pitch of the shape-of-interest portions, with respect to an object having a plurality of shape-of-interest portions of a substantially same shape, comprising: a first step of moving the object such that the shape-of-interest portions move along a same path; a second step of continuously acquiring and storing optical data of the shape-of-interest portion passing a predetermined position on the path from a fixed position, focusing on the predetermined position; a third step of calculating a focusing evaluation value, representing a numerical focusing degree at an area corresponding to the predetermined position, using a movement distance of the shape-of-interest portion of the object as a variable, according to a relationship between stored optical data and the movement distance, and obtaining a point group of combinations of the movement distance and the focusing evaluation value; and a fourth step of applying a reference curve to the point group, so as to determine the pitch based on a position where the reference curve is applied.