Patents by Inventor David F. Francis

David F. Francis 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).

  • Magnifier
    Patent number: D303119
    Type: Grant
    Filed: April 9, 1987
    Date of Patent: August 29, 1989
    Assignee: Combined Optical Industries Limited
    Inventors: Veronica G. Steel, David F. Francis
  • Magnifier
    Patent number: D303977
    Type: Grant
    Filed: April 9, 1987
    Date of Patent: October 10, 1989
    Assignee: Combined Optical Industries Limited
    Inventors: Veronica G. Steel, David F. Francis
  • Magnifier
    Patent number: D306175
    Type: Grant
    Filed: April 9, 1987
    Date of Patent: February 20, 1990
    Assignee: Combined Optical Industries Limited
    Inventors: Veronica G. Steel, David F. Francis