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AssigneeU.S. Philips Corporation
InventorsHillebrand J. J. Kraakman, Egbert Broeksema, Sjoerd Nijboer
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The invention relates to a method of manufacturing a plastic record carrier, in particular a video disc, in which a mold is provided with a fluid molding resin. A substrate is then deformed into a convex shape and pressed against the resin disposed on the center of the mold. The molding resin is rolled over the surface of the mold with a circular fluid front while the shape of the substrate is simultaneously changed from convex to planar form. After the molding resin has been spread over the entire mold and the planar substrate bears against the resin layer, the molding resin is then cured. The substrate is preferably deformed by flexibly supporting a planar substrate about its edge and then applying a different gas pressure on both sides of the substrate. The molding resin is preferably radiation-curable and is cured by exposure to, for example, ultra-violet light through the substrate.
A method of manufacturing a plastic record carrier having a stratified structure, comprising the steps of placing a relatively thick volume of a fluid molding resin centrally on a minor portion of a surface of a mold having a curved information track, the resin thereby initially covering only said minor portion of the surface of said mold, deforming a flexible substrate into a convex form bulging toward said mold, pressing the substrate against the molding resin with a pressure force, the molding resin thereby being rolled out over the remaining portions of the surface of the mold with a circular fluid front, gradually changing the configuration of said substrate from said convex form to a planar form during the pressing step until the entire information track on the surface of the mold is covered by a relatively thin layer of the resin, and curing the layer of resin, whereby the resin attaches itself to the substrate.
Dependencies are inferred from the claim text.