Patents by Inventor James A. Critchlow

James A. Critchlow 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).

  • Radially varying transmission filter for wide angle copying device
    Patent number: 4298275
    Abstract: A neutral density filter with a radially varying transmission is inserted in close proximity to the projection lens in a photocopier optical system. The filter has a transmission profile which provides compensation for photoconductor irradiance falloff due to cos.sup.4 as well as other circularly symmetrical non-uniformities in the optical system such as lens exit pupil distortion.
    Type: Grant
    Filed: January 7, 1980
    Date of Patent: November 3, 1981
    Assignee: Xerox Corporation
    Inventors: James A. Critchlow, Donna U. Ozern