Patents by Inventor Johannes Leo Antonius Marie Heldens

Johannes Leo Antonius Marie Heldens 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).

  • Device for displaying characters having a twisted nematic liquid crystal
    Patent number: 3994565
    Abstract: A device for displaying characters on a background of a different color which includes a liquid crystal having a twisted nematic configuration and two sources of polarized light of different colors the directions of polarization of which are at right angles to each other.
    Type: Grant
    Filed: June 11, 1975
    Date of Patent: November 30, 1976
    Assignee: U.S. Philips Corporation
    Inventors: Cornelis Zeger Van Doorn, Johannes Leo Antonius Marie Heldens