Abstract: The apparatus is a contamination free stamper holder for molding discs for information storage. The stamper, the disc part of the mold holding the pits and grooves to be formed on the molded plastic, is held within the mold by one or more magnets that are completely enclosed within non-magnetic material. The wall thickness of the enclosing material between the magnets and the stamper is limited so that there is no significant loss in magnetic attraction.

Abstract: The disclosure is for a film coating which yields increased life for optical media molds and the method and apparatus for making such a film. The film is a carbon nitride layer of 0.5 to 5.0 microns thickness with 2% to 45% nitrogen coated on an underlayer. One method of making the carbon nitride film is by the use of a pulsed carbon arc to generate a carbon plasma while injecting nitrogen into the vacuum chamber in which the arc is created. Another method is to generate a radio frequency plasma in a vacuum chamber into which acetylene and nitrogen gas are injected. The carbon nitride is formed by the combination of nitrogen with the carbon from the acetylene.

Abstract: The invention is a compact disc manufacturing mold which permits the mold to be used to produce a variety of non-standard sizes and shapes. A replaceable flat cavity ring which fits between the conventional mold pieces encloses the outer boundary of the disc and has an inner shape which defines the non-standard disc shape. The cavity ring includes a cylindrical projection extending from its surface which is in contact with the face of the mold piece. The extension is inserted into a groove in the mold face and is locked into the mold by threaded plugs screwed through the cylindrical sides of the mold piece.

Abstract: The disclosure is for a film coating which yields increased life for optical media molds and the method and apparatus for making such a film. The film is a carbon nitride layer of 0.5 to 5.0 microns thickness with 2% to 45% nitrogen coated on an underlayer. One method of making the carbon nitride film is by the use of a pulsed carbon arc to generate a carbon plasma while injecting nitrogen into the vacuum chamber in which the arc is created. Another method is to generate a radio frequency plasma in a vacuum chamber into which acetylene and nitrogen gas are injected. The carbon nitride is formed by the combination of nitrogen with the carbon from the acetylene.

Abstract: The invention is a compact disc manufacturing mold which permits the mold to be used to produce a variety of non-standard sizes and shapes. A replaceable flat cavity ring which fits between the conventional mold pieces encloses the outer boundary of the disc and has an inner shape which defines the non-standard disc shape. The cavity ring includes a cylindrical projection extending from its surface which is in contact with the face of the mold piece. The extension is inserted into a groove in the mold face and is locked into the mold by threaded plugs screwed through the cylindrical sides of the mold piece.

Abstract: The disclosure is for an improved film coating useable on optical media molds and the apparatus for and method of making such a film. The film is a diamond-like carbon layer of 0.3 to 3.0 microns coated on a titanium underlayer of 0.1 to 1.0 microns. The method of making the diamond-like carbon film is to deposit a defect free underlayer coating on to the steel substrate of the mold using an electron beam coating apparatus that has a hollow cathode electron beam generator and a rotating crucible containing the coating material. The diamond-like carbon film is then produced on top of the underlayer coating.

Abstract: The apparatus is a hub bushing, called a gate insert, for an optical disc mold in which a thermally conductive but soft metal base structure is coated with a thin film physical vapor deposition or chemical vapor deposition coating which furnishes an extremely hard coating to protect the surfaces from wear. The base structure material of the gate insert is copper, aluminum, or a copper or aluminum based alloy, and typical materials used for the physical vapor deposition or chemical vapor deposition coating are titanium nitride, titanium carbide, or titanium carbonitride. Since the coating is only a few micrometers thick it has virtually no affect on the excellent thermal conductivity of the base structure, and the high thermal conductivity of the gate insert prevents quality degradation in the optical discs produced by the mold because the mold surfaces are prevented from having too great a difference in temperatures.