Patents Assigned to Plasmon Data Systems, Inc.
  • Patent number: 5406540
    Abstract: A method and apparatus for improving optical disk recording performance is disclosed, which comprises reading data from an optical disk while writing data to the disk in order to verify the data, to control the power of the recording laser and to prevent overwriting of the disk.
    Type: Grant
    Filed: November 22, 1993
    Date of Patent: April 11, 1995
    Assignee: Plasmon Data Systems, Inc.
    Inventors: Robert J. Longman, Peter R. Helfet, Quentin J. Lister, Mark J. Broadbent
  • Patent number: 5137617
    Abstract: A method of reducing the surface noise of optical disk products of the type having a surface relief pattern is disclosed. In one embodiment, an adherent layer is applied to the substrate of the disk before it is coated with the recording material layer. In another embodiment, a polymeric replica produced from a master disk is treated by spin coating or dipping in a weak solvent which serves to smooth out microscopic roughness thereby removing surface irregularities. In a third embodiment, a metal coated replica is subjected to an electropolishing operation which again serves to remove a small amount of metal material, preferentially from "high spots".
    Type: Grant
    Filed: August 9, 1989
    Date of Patent: August 11, 1992
    Assignee: Plasmon Data Systems, Inc.
    Inventors: Peter R. Helfet, Robert J. Longman, Jitka Brynjolffssen
  • Patent number: 4866696
    Abstract: A pre-formatted optical data storage member is described in which format zones are generated by the provision in the surface of the optical medium of a "moth-eye" structure, i.e. regular surface pattern in the form of an arrangement of grooves or protuberances. The pitch and depth of the pattern is such that when irradiated with illumination of predetermined optical characteristics, the format zones display a reflectivity substantially lower than that of the remainder of the optical storage member. Methods of producing optical data storage members with such pre-formatting are also described.
    Type: Grant
    Filed: February 26, 1988
    Date of Patent: September 12, 1989
    Assignee: Plasmon Data Systems, Inc.
    Inventors: Robert J. Longman, Peter R. Helfet, Philip A. Storey