Patents by Inventor Wilhelm E. Krahn

Wilhelm E. Krahn 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).

  • Perimeter
    Patent number: 4145123
    Abstract: A perimeter for perimetric eye testing is provided with an electronic control mechanism for varying the brightness of the light signals in a preselected manner such that reproducibility of the examination can be achieved. An optical indicating arrangement is included to indicate the brightness values to the examiner, while the electronic control mechanism can further control an electronic recorder for recording the results of the examination.
    Type: Grant
    Filed: March 16, 1977
    Date of Patent: March 20, 1979
    Assignee: Optische Werke G. Rodenstock
    Inventors: Wilhelm E. Krahn, Manfred Born