Patents by Inventor Stig Roland Sjoquist

Stig Roland Sjoquist 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).

  • Checking an identity, authority or check document or the like
    Patent number: 4047033
    Abstract: A document such as an ID-card is provided with check markings comprising a material based upon rare earth metals and having the property that when excited by IR radiation it emits visible light. When checking the document, the document is irradiated with pulsed IR radiation, the occurrence of corresponding visible light pulses originating from said material being detected. The visible light pulses have well defined rise and decay times dictated by the check material used, which fact is used to check that output pulses from the detector are the correct ones for indicating the genuiness of the document.
    Type: Grant
    Filed: October 21, 1975
    Date of Patent: September 6, 1977
    Assignee: AB ID-Kort
    Inventors: Thor Anders Helge Malmberg, Knut Goran Hogberg, Stig Roland Sjoquist