Process for making information carrying discs
AssigneeMinnesota Mining and Manufacturing Company
InventorDonald J. Kerfeld
Life of this patent
Estimating the term…
Abstract
Imperfections in the surface of information carrying discs, such as video discs, are avoided by an improved process of manufacture. A bead of photopolymerizable mass is moved between two surfaces, one of which is a patterned surface and the other is a surface to which the photopolymerizable mass will bond upon polymerizing. By moving the liquid mass across the patterned surface, air within the pattern is removed by the leading edge of the bead, reducing imperfections.
Claims14
A method for making an information carrying disc or disc blank which comprises (1) moving a first layer relative to a second layer from a nonparallel to a parallel position so as to spread in the form of a bead, a photopolymerizable liquid mass between the two layers, one of said layers having a patterned surface facing the other layer with a circular, arc-like, or spiral pattern of depressions, protuberances, grooves with or without modulations or combinations of depressions, protuberances and grooves with or without modulations, the other of said layers having a surface to which the photopolymerizable liquid will bond upon polymerizing, (2) then irradiating said photopolymerizable liquid to polymerize said liquid and bond the polymer formed to the other of said layers, and then (3) removing said polymer and the layer to which it is bonded from said patterned surface.
A method for making an information carrying disc or disc blank which comprises moving a bead of photopolymerizable liquid composition over a first surface by advancing said bead in front of a flexible layer having a facing surface in contact with said liquid so that said flexible layer lies substantially parallel to said first surface with said liquid between the flexible layer and the first surface in the direction from which the bead advances, and the flexible layer is angled away from the first surface in the direction towards which the bead advances, and there is a supporting surface located on the side of the flexible layer away from said facing surface along the length of the flexible layer at least in part between the area of the flexible layer that changes from angling away from the first surface to lying parallel to said first surface, by bending said flexible layer wherein one of said first surface and said facing surface has a patterned surface in contact with said photopolymerizable liquid which is selected from the group consisting of circular patterns, arc-like patterns, and spiral patterns of depressions, grooves, protuberances and combinations of depressions, grooves and protuberances, advancing the bead until it covers the area of the patterned surface, irradiating said polymerizable liquid to convert it to a polymeric resin and bond it to whichever of said first surface and facing surface which is not said patterned surface, and then removing said polymeric resin and the surface to which it is bonded from said patterned surface.
Dependencies are inferred from the claim text.