PRODUCING A REPLICATE VIDEO DISC BY A METHOD OF PHOTOGRAPHIC CONTACT PRINTING

摘要

PRODUCING A REPLICATE VIDEO DISC BY A METHOD OF PHOTOGRAPHIC CONTACT PRINTING A photographic contact printing process is disclosed having application in the mass production of replicate video discs from a master disc, and other applications wherein it is desired to replicate microdetail over a relatively large area. A problem with conventional contact printing from a mask to a photographic medium is one of maintaining intimate contact over a relatively large area since dust, dirt, etc., are almost impossible to completely eliminate in any practical manner. In accordance with the present invention, a contact printing process is proposed wherein intimate contact is not necessary for making high quality contact prints. The present invention recognizes that in contact printing information from a master disc to a replicate disc, the contact printing process is significantly less sensitive to imperfect contact between the master disc and the replicate disc if one employs a replicate disc comprising a photosensitive material having certain optical properties. In particular, the photosensitive material initially has a high level of absorption to the actinic radiation used for exposure but, under the influence of such actinic radiation, the absorption decays to a lower level during exposure.