Patents by Inventor Geoffrey N. Drummond

Geoffrey N. Drummond has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5427669
    Abstract: An enhanced DC plasma processing system which acts to immediately stop current from flowing through the plasma allows a variety of alternative embodiments for varying applications. In one embodiment, a tapped inductor is switched to ground to achieve substantial voltage reversal of about 10% upon detection of an arc condition through voltage and/or rate of voltage change techniques. This reversal of voltage is maintained long enough to allow restoration of uniform charge density within the plasma prior to restoration of the initial driving condition. A technique for preventing arc discharges involving periodically applying a reverse voltage is effected through a timer system in the power supply.
    Type: Grant
    Filed: December 30, 1992
    Date of Patent: June 27, 1995
    Assignee: Advanced Energy Industries, Inc.
    Inventor: Geoffrey N. Drummond