Patents by Inventor Harald de la Croix

Harald de la Croix 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: 4012136
    Abstract: A projecting device, particularly for use in photogrammetry, employs a Fresnel condensor for illuminating a picture carrier which is imaged through an objective, including a diaphragm, onto a projection table. At least half of the illumination rays entering said objective, is suppressed by said diaphragm. The Fresnel condensor and the severe stopping-down of the objective produce interfering chromatical effects on the projection table. Said chromatical effects are eliminated either by means of a bi- or multifocal embodiment of the Fresnel lens or by insertion of optical means which extend the optical illumination path or by a respective embodiment of the light source.
    Type: Grant
    Filed: February 5, 1975
    Date of Patent: March 15, 1977
    Assignee: Jenoptik Jena G.m.b.H.
    Inventors: Harald de la Croix, Wilfried Muller