A beam of light emitted from a light source and then modulated is focused through a write head onto a surface of a substrate which is coated with a photosensitive material and is rotated at a predetermined constant rotational speed. The write head and the substrate are displaced relatively in the radial...http://www.google.se/patents/US5119359?utm_source=gb-gplus-sharePatent US5119359 - Method and apparatus for fabricating an optical disc master and an optical disc
