Patents by Inventor David Herbert Roach

David Herbert Roach 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: 9284459
    Abstract: A conductive paste composition contains a source of an electrically conductive metal, an alkaline-earth-metal boron tellurium oxide, and an organic vehicle. An article such as a high-efficiency photovoltaic cell is formed by a process of deposition of the paste composition on a semiconductor device substrate (e.g., by screen printing) and firing the paste to remove the organic vehicle and sinter the metal and establish electrical contact between it and the device.
    Type: Grant
    Filed: November 19, 2014
    Date of Patent: March 15, 2016
    Assignee: E I DU PONT DE NEMOURS AND COMPANY
    Inventors: Zhigang Rick Li, Kurt Richard Mikeska, David Herbert Roach, Carmine Torardi, Paul Douglas Vernooy
  • Patent number: 9236161
    Abstract: A conductive paste composition contains a source of an electrically conductive metal, a Ti—Te—Li oxide, and an organic vehicle. An article such as a high-efficiency photovoltaic cell is formed by a process of deposition of the paste composition on a semiconductor substrate (e.g., by screen printing) and firing the paste to remove the organic vehicle and sinter the metal and establish electrical contact between it and the device.
    Type: Grant
    Filed: September 3, 2013
    Date of Patent: January 12, 2016
    Assignee: E I DU PONT DE NEMOURS AND COMPANY
    Inventors: Kurt Richard Mikeska, David Herbert Roach, Carmine Torardi, Paul Douglas Vernooy
  • Publication number: 20150068598
    Abstract: A conductive paste composition contains a source of an electrically conductive metal, an alkaline-earth-metal boron tellurium oxide, and an organic vehicle. An article such as a high-efficiency photovoltaic cell is formed by a process of deposition of the paste composition on a semiconductor device substrate (e.g., by screen printing) and firing the paste to remove the organic vehicle and sinter the metal and establish electrical contact between it and the device.
    Type: Application
    Filed: November 19, 2014
    Publication date: March 12, 2015
    Inventors: ZHIGANG RICK LI, Kurt Richard Mikeska, David Herbert Roach, Carmine Torardi, Paul Douglas Vernooy
  • Patent number: 8900488
    Abstract: A conductive paste composition contains a source of an electrically conductive metal, an alkaline-earth-metal boron tellurium oxide, and an organic vehicle. An article such as a high-efficiency photovoltaic cell is formed by a process of deposition of the paste composition on a semiconductor device substrate (e.g., by screen printing) and firing the paste to remove the organic vehicle and sinter the metal and establish electrical contact between it and the device.
    Type: Grant
    Filed: September 3, 2013
    Date of Patent: December 2, 2014
    Assignee: E I du Pont de Nemours and Company
    Inventors: Zhigang Rick Li, Kurt Richard Mikeska, David Herbert Roach, Carmine Torardi, Paul Douglas Vernooy
  • Publication number: 20140061830
    Abstract: A conductive paste composition contains a source of an electrically conductive metal, an alkaline-earth-metal boron tellurium oxide, and an organic vehicle. An article such as a high-efficiency photovoltaic cell is formed by a process of deposition of the paste composition on a semiconductor device substrate (e.g., by screen printing) and firing the paste to remove the organic vehicle and sinter the metal and establish electrical contact between it and the device.
    Type: Application
    Filed: September 3, 2013
    Publication date: March 6, 2014
    Applicant: E I DU PONT DE NEMOURS AND COMPANY
    Inventors: ZHIGANG RICK LI, Kurt Richard Mikeska, David Herbert Roach, Carmine Torardi, Paul Douglas Vernooy
  • Publication number: 20140061831
    Abstract: A conductive paste composition contains a source of an electrically conductive metal, a Ti—Te—Li oxide, and an organic vehicle. An article such as a high-efficiency photovoltaic cell is formed by a process of deposition of the paste composition on a semiconductor substrate (e.g., by screen printing) and firing the paste to remove the organic vehicle and sinter the metal and establish electrical contact between it and the device.
    Type: Application
    Filed: September 3, 2013
    Publication date: March 6, 2014
    Applicant: E I DU PONT DE NEMOURS AND COMPANY
    Inventors: KURT RICHARD MIKESKA, David Herbert Roach, Carmine Torardi, Paul Douglas Vernooy
  • Patent number: 8529798
    Abstract: This invention provides a process for improving the field emission of an electron field emitter comprised of an acicular emitting substance such as acicular carbon, an acicular semiconductor, an acicular metal or a mixture thereof, comprising applying a force to the surface of the electron field emitter wherein the force results in the removal of a portion of the electron field emitter thereby forming a new surface of the electron field emitter.
    Type: Grant
    Filed: October 27, 2008
    Date of Patent: September 10, 2013
    Assignee: E I du Pont de Nemours and Company
    Inventors: Robert Joseph Bouchard, Lap-Tap Andrew Cheng, David Herbert Roach, John Gerard Lavin
  • Patent number: 8309223
    Abstract: A method is disclosed for the manufacture of a powdered polyimide extrudate for use as a purge media. The method includes feeding a polyimide film material into an extruder having a first zone that provides heating and a subsequent second zone that provides endothermic shearing. In one embodiment, the resulting purge media comprises a sheared polyimide powder having an average particle size in a range of about 5 to 100 microns (or any sub-range thereof). The purge media can comprises up to 35 weight percent other additives.
    Type: Grant
    Filed: December 21, 2010
    Date of Patent: November 13, 2012
    Inventor: David Herbert Roach
  • Patent number: 8298449
    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: July 14, 2010
    Date of Patent: October 30, 2012
    Assignee: E I du Pont de Nemours and Company
    Inventors: Robert Joseph Bouchard, Lap-Tak Andrew Cheng, Kenneth Warren Hang, David Herbert Roach
  • Publication number: 20120003476
    Abstract: A method is disclosed for the manufacture of a powdered polyimide extrudate for use as a purge media. The method includes feeding a polyimide film material into an extruder having a first zone that provides heating and a subsequent second zone that provides endothermic shearing. In one embodiment, the resulting purge media comprises a sheared polyimide powder having an average particle size in a range of about 5 to 100 microns (or any sub-range thereof). The purge media can comprises up to 35 weight percent other additives.
    Type: Application
    Filed: December 21, 2010
    Publication date: January 5, 2012
    Applicant: E. I. DU PONT DE NEMOURS AND COMPANY
    Inventor: DAVID HERBERT ROACH
  • Publication number: 20110316177
    Abstract: A method is disclosed for making polyimide powder. The method includes feeding polyimide film material into an extruder, where the extruder has at least one heating zone. The feed rate into the extruder is less than the maximum feed rate of the extruder. The material is then extruded for at least 0.5 seconds at a temperature greater than 300° C. to provide a powdered extrudate.
    Type: Application
    Filed: December 20, 2010
    Publication date: December 29, 2011
    Applicant: E.I. DU PONT DE NEMOURS AND COMPANY
    Inventor: DAVID HERBERT ROACH
  • Patent number: 8076834
    Abstract: A field emission device in which a protecting vapor is present in an evacuated space between a field emission cathode assembly and an anode. The protecting vapor may be one or more hydrogen-containing gases such as a gas containing M—H bonds where M may be C, Si, B, Al or P.
    Type: Grant
    Filed: August 20, 2008
    Date of Patent: December 13, 2011
    Assignee: E.I. du Pont de Nemours and Company
    Inventors: Adam Fennimore, David Herbert Roach
  • Patent number: 8070906
    Abstract: This invention provides a process for improving the field emission of an electron field emitter comprised of an acicular emitting substance such as acicular carbon, an acicular semiconductor, an acicular metal or a mixture thereof, comprising applying a force to the surface of the electron field emitter wherein the force results in the removal of a portion of the electron field emitter thereby forming a new surface of the electron field emitter.
    Type: Grant
    Filed: July 16, 2008
    Date of Patent: December 6, 2011
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Robert Joseph Bouchard, Lap-Tak Andrew Cheng, David Herbert Roach, John Gerard Lavin
  • Publication number: 20110232747
    Abstract: This invention relates to thick-film pastes and processes for using such pastes to make solar cell contacts and other circuit devices. In particular, the thick-film pastes comprise a lead-tellurium-oxide frit component, an organic vehicle, and a conductive metal component comprising a silver component and a nickel component.
    Type: Application
    Filed: May 4, 2011
    Publication date: September 29, 2011
    Applicant: E. I. DU PONT DE NEMOURS AND COMPANY
    Inventors: KURT RICHARD MIKESKA, DAVID HERBERT ROACH, RAJ G. RAJENDRAN, SEIGI SUH
  • Patent number: 8011990
    Abstract: This invention provides a process for improving the field emission of an electron field emitter comprised of an acicular emitting substance such as acicular carbon, an acicular semiconductor, an acicular metal or a mixture thereof, comprising applying a force to the surface of the electron field emitter wherein the force results in the removal of a portion of the electron field emitter thereby forming a new surface of the electron field emitter.
    Type: Grant
    Filed: September 29, 2005
    Date of Patent: September 6, 2011
    Assignee: E.I. du Pont de Nemours and Company
    Inventors: Robert Joseph Bouchard, Lap-Tak Andrew Cheng, David Herbert Roach
  • Publication number: 20110101859
    Abstract: A field emission device in which a protectin vapor is present in an evacuated space between a field emission cathode assembly and an anode. The protectin vapor may be one or more hydrogen-containing gases suc as a gas containing M—H bonds where M may be C, Si, B, Al or P. The protecting vapor has within the evacuated space a partial pressure greater than about 10?8 Torr (1.33×10?6Pe) et 20° C.
    Type: Application
    Filed: August 20, 2008
    Publication date: May 5, 2011
    Applicant: E. I. DU PONT DE NEMOURS AND COMPANY
    Inventors: Adam Fennimore, David Herbert Roach
  • Publication number: 20110006271
    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: July 14, 2010
    Publication date: January 13, 2011
    Applicant: E.I DU PONT DE NEMOURS AND COMPANY
    Inventors: Robert Joseph Bouchard, Lap-Tak Andrew Cheng, David Herbert Roach, Kenneth Warren Hang
  • Publication number: 20100239490
    Abstract: Processes for producing single-wall carbon nanotubes without catalysts are provided. The nanotubes are produced by vaporizing silicon carbide and carbon.
    Type: Application
    Filed: March 15, 2006
    Publication date: September 23, 2010
    Inventors: David Herbert Roach, Gillian Althea Maria Reynolds
  • Patent number: 7750544
    Abstract: This invention provides compositions of matter that contain an electron emitting substance and an expansion material. The expansion material may, for example, be an intercalation compound. When a film is formed from the composition, expansion of the expansion material typically causes rupturing or fracturing of the film. No further treatment of the surface of the film is typically required after expansion of the expansion material to obtain good emission properties. A surface formed from such a fractured film acts as an efficient electron field emitter and thus is useful in vacuum microelectronic devices.
    Type: Grant
    Filed: March 27, 2007
    Date of Patent: July 6, 2010
    Assignee: E.I. du Pont de Nemours and Company
    Inventors: Lap-Tak Andrew Cheng, David Herbert Roach
  • Publication number: 20100119435
    Abstract: Processes for increasing the production rate of single-wall carbon nanotubes using a disordered carbon target are disclosed. The processes use a disordered carbon target and include vaporization of the target in the presence of a non-oxidizing gas. The single-wall nanotubes produced can be incorporated into electronic devices such as diodes and transistors.
    Type: Application
    Filed: March 15, 2006
    Publication date: May 13, 2010
    Inventors: David Herbert Roach, Gillian Althea Maria Reynolds