Patents by Inventor John S. Dowell

John S. Dowell 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: 4346987
    Abstract: A system for projecting an image, via projection optics, from multiple circuits formed on a glass master onto a photoresist coated PCB panel. The projection optics precisely magnifies the reduced pattern formed on the master to full scale while maintaining the image-plane light uniformity. To insure proper magnification, the conjugate distances between the master and the projection optics and between the projection optics and the PCB panel are precisely controlled. Further, the relevant planes containing the master, optics and PCB panel are controlled to insure substantial perpendicularity with respect to the optical axis. A registration subsystem is also provided to register the PCB panelholding platen.
    Type: Grant
    Filed: July 18, 1980
    Date of Patent: August 31, 1982
    Assignee: Xerox Corporation
    Inventors: Phijit Jalichandra, John S. Dowell, John A. Carlson