Patents by Inventor Carl E. A. Johnson

Carl E. A. Johnson 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).

  • Inspection apparatus and method for detecting flaws on a diffractive surface
    Patent number: 4943734
    Abstract: An optical inspection system and method for detecting flaws on a diffractive surface such as a reticle or wafer, includes illuminating a surface to be inspected to generate a first scattered energy angular distribution in response to a flaw on the surface and a second scattered energy angular distribution in response to an unflawed surface; the first and second energy distributions are sensed and the minimum energy detection energy level is established; determining whether the minimum detected energy level is in a first or second predetermined energy range and indicating that no flaw is present when the minimum detected energy level is in the first range and a flaw is present when the minimum detected energy level is in the second range.
    Type: Grant
    Filed: June 30, 1989
    Date of Patent: July 24, 1990
    Assignee: QC Optics, Inc.
    Inventors: Carl E. A. Johnson, Jay L. Ormsby, Eric T. Chase, George S. Quackenbos, Sergey V. Broude, Abdu Bou dour