Patents by Inventor Heikki Helava

Heikki Helava 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: 9728660
    Abstract: The present invention relates to a solid state switch that may be used as in optically-triggered switch in a variety of applications. In particular, the switch may allow for the reduction of gigawatt systems to approximately shoebox-size dimension. The optically-triggered switches may be included in laser triggered systems or antenna systems.
    Type: Grant
    Filed: August 14, 2013
    Date of Patent: August 8, 2017
    Assignee: The Curators of the University of Missouri
    Inventors: Randy D. Curry, Heikki Helava
  • Patent number: 9716202
    Abstract: The present invention relates to a solid-state optically activated switch that may be used as limiting switch in a variety of applications or as a high voltage switch. In particular, the switch may incorporate the photoconductive properties of a semiconductor to provide the limiting function in a linear mode. In one embodiment, a configuration of the switch allows for greater than 99.9999% off-state transmission and an on-state limiting of less than 0.0001% of the incident signal.
    Type: Grant
    Filed: August 13, 2013
    Date of Patent: July 25, 2017
    Assignee: The Curators of the University of Missouri
    Inventors: Randy D. Curry, Robert Druce, Nathaniel Kinsey, Heikki Helava
  • Publication number: 20150221804
    Abstract: The present invention relates to a solid-state optically activated switch that may be used as limiting switch in a variety of applications or as a high voltage switch. In particular, the switch may incorporate the photoconductive properties of a semiconductor to provide the limiting function in a linear mode. In one embodiment, a configuration of the switch allows for greater than 99.9999% off-state transmission and an on-state limiting of less than 0.0001% of the incident signal.
    Type: Application
    Filed: August 13, 2013
    Publication date: August 6, 2015
    Inventors: Randy D. Curry, Robert Druce, Nathaniel Kinsey, Heikki Helava
  • Publication number: 20150187970
    Abstract: The present invention relates to a solid state switch that may be used as in optically-triggered switch in a variety of applications. In particular, the switch may allow for the reduction of gigawatt systems to approximately shoebox-size dimension. The optically-triggered switches may be included in laser triggered systems or antenna systems.
    Type: Application
    Filed: August 14, 2013
    Publication date: July 2, 2015
    Inventors: Randy D. Curry, Heikki Helava
  • Publication number: 20060174826
    Abstract: A crucible is provided that is thermally stable at high temperatures and is suitable for use in the growth of large, bulk AlN, AlxGa1-xN or other nitride single crystals. The crucible is comprised of specially treated tantalum. During the initial treatment, the walls of the crucible are carburized, thus achieving a crucible that can be subjected to high temperatures without deformation. Once the carburization of the tantalum is complete, the crucible undergoes further treatment to protect the surfaces that are expected to come into contact with nitride vapors during crystal growth with a layer of TaN. If the crucible is to be used with a graphite furnace, only the inner surfaces of the crucible are converted to TaN, thus keeping TaC surfaces adjacent to the graphite furnace elements. If the crucible is to be used with a non-graphite furnace, both the inner and outer surfaces of the crucible are converted to TaN.
    Type: Application
    Filed: March 31, 2006
    Publication date: August 10, 2006
    Inventors: Heikki Helava, Mark Ramm
  • Publication number: 20050178315
    Abstract: A crucible is provided that is thermally stable at high temperatures and is suitable for use in the growth of large, bulk AlN, AlxGa1-xN or other nitride single crystals. The crucible is comprised of specially treated tantalum. During the initial treatment, the walls of the crucible are carburized, thus achieving a crucible that can be subjected to high temperatures without deformation. Once the carburization of the tantalum is complete, the crucible undergoes further treatment to protect the surfaces that are expected to come into contact with nitride vapors during crystal growth with a layer of TaN. If the crucible is to be used with a graphite furnace, only the inner surfaces of the crucible are converted to TaN, thus keeping TaC surfaces adjacent to the graphite furnace elements. If the crucible is to be used with a non-graphite furnace, both the inner and outer surfaces of the crucible are converted to TaN.
    Type: Application
    Filed: February 13, 2004
    Publication date: August 18, 2005
    Inventors: Heikki Helava, Mark Ramm