Patents by Inventor David Herbert Roadh

David Herbert Roadh 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: 7763189
    Abstract: This invention provides a dielectric composition comprising a dielectric which is fireable in air at a temperature in the range of about 450° C. to about 550° C. and a conductive oxide selected from the group consisting of antimony-doped tin oxide, tin-doped indium oxide, a transition metal oxide which has mixed valence states or will form mixed valence states after firing in a nitrogen atmosphere at a temperature in the range of about 450° C. to about 550° C. and normally conducting precious metal oxides such as ruthenium dioxide, wherein the amount of conductive oxide present is from about 0.25 wt % to about 25 wt % of the total weight of dielectric and conductive oxide. This dielectric composition has reduced electrical resistance and is useful in electron field emission devices to eliminate charging of the dielectric in the vicinity of the electron emitter and the effect of static charge induced field emission.
    Type: Grant
    Filed: May 14, 2002
    Date of Patent: July 27, 2010
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Robert Joseph Bouchard, Lap-Tak Andrew Cheng, David Herbert Roadh, Kenneth Warren Hang
  • Publication number: 20040169166
    Abstract: This invention provides a dielectric composition comprising a dielectric which is fireable in air at a temperature in the range of about 450° C. to about 550° C. and a conductive oxide selected from the group consisting of antimony-doped tin oxide, tin-doped indium oxide, a transition metal oxide which has mixed valence states or will form mixed valence states after firing in a nitrogen atmosphere at a temperature in the range of about 450° C. to about 550° C. and normally conducting precious metal oxides such as ruthenium dioxide, wherein the amount of conductive oxide present is from about 0.25 wt % to about 25 wt % of the total weight of dielectric and conductive oxide. This dielectric composition has reduced electrical resistance and is useful in electron field emission devices to eliminate charging of the dielectric in the vicinity of the electron emitter and the effect of static charge induced field emission.
    Type: Application
    Filed: April 22, 2004
    Publication date: September 2, 2004
    Inventors: Robert Joseph Bouchard, Lap-Tak Andrew Cheng, David Herbert Roadh, Kenneth Warren Hang