Patents by Inventor Frederik Karel Lotgering

Frederik Karel Lotgering 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).

  • Magnetic device operating with the photomagnetic effect
    Patent number: 4020475
    Abstract: A magnetic device which can be driven by means of electromagnetic radiation and has a radiation-sensitive element consisting of cobalt-doped yttrium-iron garnet. Exposure to electromagnetic radiation produces a decrease of the magnetic permeability of the element which decrease is permanent until the element is demagnetized and occurs at temperatures from 77.degree. K to room temperature.
    Type: Grant
    Filed: October 17, 1975
    Date of Patent: April 26, 1977
    Assignee: U.S. Philips Corporation
    Inventors: Frederik Karel Lotgering, Petrus Helena Gerardus Maria Vromans