Patents by Inventor Duco Van Aalst

Duco Van Aalst 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: 6182402
    Abstract: An apparatus for the viewing of an inmate in a cell while preventing the inmate from determining if he is being observed includes a frame enclosure with means for securing the apparatus about a cell window attached to the frame structure. A two-way mirror is attached to the frame enclosure and disposed proximate the cell window. A sheet of light attenuating material is disposed in the frame enclosure in planar alignment with respect to the two-way mirror a predetermined distance therefrom to darken the area intermediate the two-way mirror and the sheet of light attenuation material. Means for viewing through the two-way mirror are provided which include a lens or a video camera and display. An optional slot allows for manual positioning of the lens to permit optimum viewing into the cell. The means for securing includes a plurality of magnets disposed around the perimeter of the frame enclosure or by use of a hook and loop fastener.
    Type: Grant
    Filed: July 8, 1998
    Date of Patent: February 6, 2001
    Inventor: Duco Van Aalst