Method of recognizing master disk positioning mark

摘要

A positioning mark of a soft magnetic film is provided at the center of a master disk, and a beam from a light source irradiates the position of the mark. When a optical reception sensor using a CCD recognizes the mark, the recognizability of the positioning mark can be improved by using a wavelength selective filter or a laser as the light source. Additionally, the recognizability of the positioning mark can be improved by forming the positioning mark using a material other than a soft magnetic material.