Method for making a stamper for use in making a substrate for a digital versatile disc

Abstract

In a method for making a substrate for a digital versatile disc, a stamper having a front side with a pitted surface, a back side, and a central opening is first provided. The central opening is defined by a surface having an edge on the front side and an edge on the back side. A burr is formed on the edge of the surface on the front side of the stamper, e.g., by punching the central hole from the back side of the stamper. The stamper is then disposed within a mold such that the front side faces the mold cavity. Thereafter, the substrate is molded in the mold. In the molding process, the burr on the front side of the stamper forms a rounded edge in one of the walls defining an annular groove in the substrate. This rounded edge enables substrates to be bonded together with an extremely thin layer of adhesive material without the centering and alignment problems caused by burrs. A digital versatile disc including a substrate formed by this method and a method for forming a stamper for use in the manufacture of a substrate for a digital versatile disc also are described.

Dependencies are inferred from the claim text.