Patents by Inventor Peter G. Hofstra

Peter G. Hofstra 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: 7372436
    Abstract: The present invention introduces a novel design for active matrix displays, utilizing both organic light-emitting diode (OLED) and thin-film electroluminescent technologies. In a first aspect there is provided a top-emitting OLED, including an optical interference contrast-enhancing stack that is placed on the top of the driving thin-film transistor, and which extendes to the entire pixel area to cover the reflecting parts of the pixel. In a second aspect, there is provided a bottom-emitting OIED wherein an optical interference contrast-enhancing stack is placed right under the driving thin-film transistor and, separately between the organic stack and the top electrode, typically a cathode. The optical interference contrast-enhancing stack suppresses light reflection from the thin-film transistor and the upper electrode.
    Type: Grant
    Filed: June 11, 2003
    Date of Patent: May 13, 2008
    Assignee: Luxell Technologies, Inc.
    Inventors: Alexey N. Krasnov, Richard P. Wood, David J. Johnson, Peter G. Hofstra
  • Patent number: 6784602
    Abstract: The present invention provides a novel organic electroluminescent device having an optical interference member which reduces the overall reflectance from the device. The invention is particularly suited to current-driven organic displays having an anode, an electroluminescent layer and a cathode, where at least one optical interference member is placed between two of the layers and thus forms part of the electrical circuit required to excite the display. The optical interference member is chosen to have a thickness which causes at least some destructive optical interference of ambient light incident on the display. In addition, the material(s) of the optical interference member are chosen to have a work function which is compatible with the highest occupied molecular orbital, or the lowest unoccupied molecular orbital of the electroluminescent layer, depending on the location of the optical interference member in relation to the anode, cathode and electroluminescent layer.
    Type: Grant
    Filed: October 25, 2001
    Date of Patent: August 31, 2004
    Assignee: Luxell Technologies Inc.
    Inventors: Peter G. Hofstra, Alexey Krasnov
  • Publication number: 20040052931
    Abstract: The present invention provides a novel organic electroluminescent device having an optical interference member which reduces the overall reflectance from the device. The invention is particularly suited to current-driven organic displays having an anode, an electroluminescent layer and a cathode, where at least one optical interference member is placed between two of the layers and thus forms part of the electrical circuit required to excite the display. The optical interference member is chosen to have a thickness which causes at least some destructive optical interference of ambient light incident on the display. In addition, the material(s) of the optical interference member are chosen to have a work function which is compatible with the highest occupied molecular orbital, or the lowest unoccupied molecular orbital of the electroluminescent layer, depending on the location of the optical interference member in relation to the anode, cathode and electroluminescent layer.
    Type: Application
    Filed: April 14, 2003
    Publication date: March 18, 2004
    Inventors: Peter G. Hofstra, Alexey N. Krasnov
  • Publication number: 20030214230
    Abstract: The present invention provides an electroluminescent device having a dark layer for reducing at least a portion of ambient light incident on the display. In one bottom emitting device embodiment, the dark layer is placed between the emitting layer and a reflective rear cathode. The dark layer comprises a partially reflective layer, an absorptive-transmissive layer, and a reflective layer.
    Type: Application
    Filed: March 10, 2003
    Publication date: November 20, 2003
    Inventors: Richard P. Wood, Peter G. Hofstra, David J. Johnson, Alexey N. Krasnov
  • Publication number: 20030127971
    Abstract: The present invention provides a novel organic electroluminescent device having an optical interference member which reduces the overall reflectance from the device. The invention is particularly suited to current-driven organic displays having an anode, an electroluminescent layer and a cathode, where at least one optical interference member is placed between two of the layers and thus forms part of the electrical circuit required to excite the display. The optical interference member is chosen to have a thickness which causes at least some destructive optical interference of ambient light incident on the display. In addition, the material(s) of the optical interference member are chosen to have a work function which is compatible with the highest occupied molecular orbital, or the lowest unoccupied molecular orbital of the electroluminescent layer, depending on the location of the optical interference member in relation to the anode, cathode and electroluminescent layer.
    Type: Application
    Filed: October 25, 2001
    Publication date: July 10, 2003
    Inventors: Peter G. Hofstra, Alexey Krasnov
  • Patent number: 6551651
    Abstract: The present invention provides a novel organic electroluminescent device having an optical interference member which reduces the overall reflectance from the device. The invention is particularly suited to current-driven organic displays having an anode, an electroluminescent layer and a cathode, where at least one optical interference member is placed between two of the layers and thus forms part of the electrical circuit required to excite the display. The optical interference member is chosen to have a thickness which causes at least some destructive optical interference of ambient light incident on the display. In addition, the material(s) of the optical interference member are chosen to have a work function which is compatible with the highest occupied molecular orbital, or the lowest unoccupied molecular orbital of the electroluminescent layer, depending on the location of the optical interference member in relation to the anode, cathode and electroluminescent layer.
    Type: Grant
    Filed: October 25, 2001
    Date of Patent: April 22, 2003
    Assignee: Luxell Technologies, Inc.
    Inventors: Peter G. Hofstra, Alexey Krasnov
  • Publication number: 20020153834
    Abstract: The present invention provides a novel organic electroluminescent device having an optical interference member which reduces the overall reflectance from the device. The invention is particularly suited to current-driven organic displays having an anode, an electroluminescent layer and a cathode, where at least one optical interference member is placed between two of the layers and thus forms part of the electrical circuit required to excite the display. The optical interference member is chosen to have a thickness which causes at least some destructive optical interference of ambient light incident on the display. In addition, the material(s) of the optical interference member are chosen to have a work function which is compatible with the highest occupied molecular orbital, or the lowest unoccupied molecular orbital of the electroluminescent layer, depending on the location of the optical interference member in relation to the anode, cathode and electroluminescent layer.
    Type: Application
    Filed: October 25, 2001
    Publication date: October 24, 2002
    Inventors: Peter G. Hofstra, Alexey Krasnov
  • Patent number: 6411019
    Abstract: The present invention provides a novel organic electroluminescent device having an optical interference member which reduces the overall reflectance from the device. The invention is particularly suited to current-driven organic displays having an anode, an electroluminescent layer and a cathode, where at least one optical interference member is placed between two of the layers and thus forms part of the electrical circuit required to excite the display. The optical interference member is chosen to have a thickness which causes at least some destructive optical interference of ambient light incident on the display. In addition, the material(s) of the optical interference member are chosen to have a work function which is compatible with the highest occupied molecular orbital, or the lowest unoccupied molecular orbital of the electroluminescent layer, depending on the location of the optical interference member in relation to the anode, cathode and electroluminescent layer.
    Type: Grant
    Filed: July 27, 1999
    Date of Patent: June 25, 2002
    Assignee: Luxell Technologies Inc.
    Inventors: Peter G. Hofstra, Alexey Krasnov
  • Publication number: 20020039871
    Abstract: The present invention provides a novel organic electroluminescent device having an optical interference member which reduces the overall reflectance from the device. The invention is particularly suited to current-driven organic displays having an anode, an electroluminescent layer and a cathode, where at least one optical interference member is placed between two of the layers and thus forms part of the electrical circuit required to excite the display. The optical interference member is chosen to have a thickness which causes at least some destructive optical interference of ambient light incident on the display. In addition, the material(s) of the optical interference member are chosen to have a work function which is compatible with the highest occupied molecular orbital, or the lowest unoccupied molecular orbital of the electroluminescent layer, depending on the location of the optical interference member in relation to the anode, cathode and electroluminescent layer.
    Type: Application
    Filed: October 25, 2001
    Publication date: April 4, 2002
    Inventors: Peter G. Hofstra, Alexey Krasnov
  • Patent number: 5378574
    Abstract: Ink jet inks and liquid developers are disclosed which contain colored particles comprising hydrophilic silica particles, to the surfaces of which dyes are covalently bonded through silane coupling agents. The ink jet inks generally comprise a liquid medium and a plurality of the colored silica particles. The liquid developers generally comprise a liquid medium, a resin, a plurality of the colored silica particles, and a charge control agent. The particles are prepared by a process which comprises reacting hydrophilic silica particles with a silane coupling agent in the absence of water to form particles having covalently attached thereto coupling agents, followed by reacting a dye with the coupling agent attached to the silica particles.
    Type: Grant
    Filed: June 23, 1989
    Date of Patent: January 3, 1995
    Assignee: Xerox Corporation
    Inventors: Francoise M. Winnik, Barkev Keoshkerian, Raymond W. Wong, Stephan Drappel, Melvin D. Crocher, James D. Mayo, Peter G. Hofstra
  • Patent number: 5100471
    Abstract: An aqueous ink jet composition comprised of a solvent and colored particles comprised of a polymeric core and a silica shell onto which dyes are covalently bonded.
    Type: Grant
    Filed: June 27, 1990
    Date of Patent: March 31, 1992
    Assignee: Xerox Corporation
    Inventors: Francoise M. Winnik, Peter G. Hofstra