Patents by Inventor David K. Lees

David K. Lees 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).

  • Crystal diameter control system
    Patent number: 6226032
    Abstract: A system controls the diameter of both a neck region and a full diameter region of a monocrystalline rod being pulled from molten material held in a crucible. The system uses a video camera viewing light reflected from a meniscus around the rod where the rod emerges from a melt surface of the molten material. The video camera has a zoom lens for enlarging an image of the meniscus during growth of the neck of the rod and for reducing an image of the meniscus during growth of a full diameter body of the rod. A computer controlling a pull rate for the neck growth of the rod is rapidly responsive to a count of total camera pixels illuminated by the image of the meniscus during neck growth.
    Type: Grant
    Filed: June 10, 1997
    Date of Patent: May 1, 2001
    Assignee: General Signal Corporation
    Inventors: David K. Lees, Henry C. Latka