An improved injection molding process for producing a substrate of an optical disc having a high quality is disclosed. The process includes the steps of: fixing a stamper having protrusions corresponding to pits for recorded information or a groove for tracking onto one mold unit of a pair of mold units...http://www.google.fr/patents/US4961884?utm_source=gb-gplus-shareBrevet US4961884 - Process for producing substrate of optical disc
