Patents by Inventor Leonardus A. M. Elshof

Leonardus A. M. Elshof 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).

  • Color display tube
    Patent number: 4614893
    Abstract: A color display tube of the "in-line" type includes a shadow mask having means for producing generally elliptical equitransmission factor curves.
    Type: Grant
    Filed: November 26, 1985
    Date of Patent: September 30, 1986
    Assignee: U.S. Philips Corporation
    Inventors: Constant J. M. Geenen, Leonardus A. M. Elshof
  • Color display tube with shadow mask having elongated apertures therein
    Patent number: 4227115
    Abstract: The bridges between apertures located at the edge of the shadow mask of a color display tube are made at least 20% wider than the others. The width of the bridges increases linearly from row to row from the center to the edge of the mask whereby a continuously varying brightness distribution is obtained. The reproduction mask used in the fabrication of such a shadow mask can be made photographically by exposing photosensitive material through a pattern of bridges, rotating the pattern and repeating the exposure.
    Type: Grant
    Filed: February 21, 1979
    Date of Patent: October 7, 1980
    Assignee: U.S. Philips Corporation
    Inventors: Leonardus A. M. Elshof, Herman F. Van Heek
  • Color display tube, method of manufacturing such a display tube having a shadow mask, and reproduction mask for use in such a method
    Patent number: 4159177
    Abstract: The bridges between apertures located at the edge of the shadow mask of a color display tube are made at least 20% wider than the others. The width of the bridges increases linearly from row to row from the center to the edge of the mask whereby a continuously varying brightness distribution is obtained. The reproduction mask used in the fabrication of such a shadow mask can be made photographically by exposing photosensitive material through a pattern of bridges, rotating the pattern and repeating the exposure.
    Type: Grant
    Filed: July 8, 1977
    Date of Patent: June 26, 1979
    Assignee: U.S. Philips Corporation
    Inventors: Leonardus A. M. Elshof, Herman F. Van Heek