A method for preparing a substrate sheet for an optical recording medium has the steps of controlling a roll stamper having a preformat pattern on the peripheral surface thereof and a molding roll disposed with a predetermined gap between the same and the roll stamper so that they have a predetermined...http://www.google.de/patents/US5433897?utm_source=gb-gplus-sharePatent US5433897 - Method and apparatus for preparing substrate sheet for optical recording medium
