Manufacture of optical data storage disc
AssigneeNimbus Manufacturing (UK) Limited
InventorPaul Vedamuttu
Life of this patent
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Abstract
A method and apparatus forming a micro-relief pattern on a surface of an optical disc, which micro-relief pattern may form a holographic image in which a shim bearing a micro-relief pattern is pressed onto the surface of the disc and the apparatus used ensures that a greater force is applied to the periphery of the disc and the remainder of the surface on which it is desired to form the micro-relief pattern, such method and apparatus enables a satisfactory relief pattern to be formed over a substantial area of the surface of the disc.
Claims17
A method of providing a micro-relief pattern on an optical data storage disc formed with a peripheral ridge extending at least around part of the periphery of said disc comprising the steps of providing an embossing member adapted to form a required micro-relief pattern on the optical data storage disc, providing a support member which is thicker at its periphery than at the center, supporting said disc on said support member, applying a force to bring said embossing member and said disc into contact with each other, the application of said force being such that a relatively small initial force is first applied to the disc for a brief period of time before subsequently increasing the force to a much greater force-value to the extent where the micro-relief pattern from the embossing member is transferred to the disc, such that the force is applied in a manner to at least initially increase the pressure to which the disc is subjected in the region of said peripheral ridge compared with the remainder of the disc.
Apparatus for embossing a micro-relief pattern in an optical data storage disc formed with a peripheral ridge extending at least around part of the periphery of said disc, said apparatus comprising an embossing member adapted to provide the required micro-relief pattern on the disc, means for supporting said disc including a disc support member being thicker at its periphery than at the center, and means for applying a first relatively small initial force for a brief period of time before subsequently increasing the force to a force of much greater force value between said embossing member and said disc support member in a direction towards each other, wherein the shape of said disc support member at least initially subjects the peripheral ridge of the disc to a greater pressure than the remainder of the disc.
Dependencies are inferred from the claim text.