Patents by Inventor Rama Venkatasubramanian

Rama Venkatasubramanian 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: 7282798
    Abstract: A method and structure for heat transport, cooling, sensing and power generation is described. A photonic bandgap structure (3) is employed to enhance emissive heat transport from heat sources such as integrated circuits (2) to heat spreaders (4). The photonic bandgap structure (3) is also employed to convert heat to electric power by enhanced emission absorption and to cool and sense radiation, such as infra-red radiation. These concepts may be applied to both heat loss and heat absorption, and may be applied to heat transport and absorption enhancement in a single device.
    Type: Grant
    Filed: November 29, 2001
    Date of Patent: October 16, 2007
    Assignee: Research Triangle Institute
    Inventor: Rama Venkatasubramanian
  • Publication number: 20070215194
    Abstract: A method of forming a thermoelectric device may include forming a plurality of islands of thermoelectric material on a deposition substrate. The plurality of islands of thermoelectric material may be bonded to a header substrate so that the plurality of islands are between the deposition substrate and the header substrate. More particularly, the islands of thermoelectric material may be epitaxial islands of thermoelectric material having crystal structures aligned with a crystal structure of the deposition substrate. Related structures are also discussed.
    Type: Application
    Filed: March 2, 2007
    Publication date: September 20, 2007
    Inventors: Jayesh Bharathan, David Koester, Randall Alley, Rama Venkatasubramanian, Pratima Addepalli, Bing Shen, Cynthia Watkins
  • Patent number: 7235735
    Abstract: A thermoelectric device and method of manufacturing the device, where thermoelectric elements of opposite conductivity type are located on respective opposing sides of a heat source member. Heat sinks are disposed on opposite sides of the thermoelectric elements. Peltier metal contacts are positioned between the thermoelectric elements and each of the heat source member and heat sinks. A plurality of devices may be arranged together in a thermally parallel, electrically series arrangement, or in a thermally parallel, electrically parallel arrangement. The arrangement of the elements allow the direction of current flow through the pairs of elements to be substantially the same as the direction of current flow through the metal contacts.
    Type: Grant
    Filed: April 15, 2003
    Date of Patent: June 26, 2007
    Assignee: Nextreme Thermal Solutions, Inc.
    Inventors: Rama Venkatasubramanian, Edward P. Siivola
  • Publication number: 20070028956
    Abstract: Forming a thermoelectric device may include forming a thermoelectric superlattice including a plurality of alternating layers of different thermoelectric materials wherein a period of the alternating layers varies over a thickness of the superlattice. More particularly, forming the superlattice may include depositing the superlattice on a single crystal substrate using epitaxial deposition. In addition, the single crystal substrate may be removed from the superlattice, and a second thermoelectric superlattice may be provided with the first and second thermoelectric superlattices having opposite conductivity types. Moreover, the first and second thermoelectric superlattices may be thermally coupled in parallel between two thermally conductive plates while electrically coupling the first and second thermoelectric superlattices in series. Related materials and devices and structures are also discussed.
    Type: Application
    Filed: April 12, 2006
    Publication date: February 8, 2007
    Inventors: Rama Venkatasubramanian, Edward Siivola, Brooks O'Quinn, James Caylor, Jonathan Pierce
  • Patent number: 7164077
    Abstract: A thermoelectric cooling and heating device including a substrate, a plurality of thermoelectric elements arranged on one side of the substrate and configured to perform at least one of selective heating and cooling such that each thermoelectric element includes a thermoelectric material, a Peltier contact contacting the thermoelectric material and forming under electrical current flow at least one of a heated junction and a cooled junction, and electrodes configured to provide current through the thermoelectric material and the Peltier contact. As such, the thermoelectric cooling and heating device selectively biases the thermoelectric elements to provide on one side of the thermolectric device a grid of localized heated or cooled junctions.
    Type: Grant
    Filed: April 9, 2002
    Date of Patent: January 16, 2007
    Assignee: Research Triangle Institute
    Inventor: Rama Venkatasubramanian
  • Publication number: 20060289052
    Abstract: A method of forming a thermoelectric device may include forming a first electrically conductive trace, and bonding a thermoelectric element to the first electrically conductive trace. After bonding the thermoelectric element to the first electrically conductive trace, a metal post may be formed on the thermoelectric element so that the thermoelectric element is between the first electrically conductive trace and the metal post. After forming the metal post, the metal post may be bonded to a second electrically conductive trace so that the metal post is between the second electrically conductive trace and the thermoelectric element. Other related methods and structures are also discussed.
    Type: Application
    Filed: June 21, 2006
    Publication date: December 28, 2006
    Inventors: Brooks O'Quinn, Rama Venkatasubramanian, Edward Siivola
  • Publication number: 20060243317
    Abstract: A thermoelectric generator may include first and second thermally conductive plates and a plurality of pairs of P-type and N-type thermoelectric elements. The first thermally conductive plate may be configured to generate heat responsive to solar radiation, and the first and second thermally conductive plates may be spaced apart. The P-type and N-type thermoelectric elements of each pair may be electrically coupled in series, and the P-type and N-type thermoelectric elements of each pair may be thermally coupled in parallel between the first and second thermally conductive plates.
    Type: Application
    Filed: April 18, 2006
    Publication date: November 2, 2006
    Inventor: Rama Venkatasubramanian
  • Publication number: 20060225773
    Abstract: A thermoelectric device having at least one unipolar couple element (22) including two legs (22a) of a same electrical conductivity type. A first-temperature stage (24) is connected to one of the two legs. A second-temperature stage (28) is connected across the legs of the at least one unipolar couple element. A third-temperature stage (30) is connected to the other of the two legs. Methods for cooling an object and for thermoelectric power conversion utilize the at least one unipolar couple element to respectively cool an object and produce electrical power.
    Type: Application
    Filed: November 25, 2003
    Publication date: October 12, 2006
    Inventors: Rama Venkatasubramanian, Kip Coonley, Edward Siivola, Michael Puchan, Randall Alley, Pratima Addepalli, Brooks O'Quinn, Thomas Colpitts, Mary Napier
  • Publication number: 20060086118
    Abstract: A structure, system and method for controlling a temperature of a heat generating device in a solid medium, wherein heat is extracted from the medium into at least one heat extraction device, the heat extraction device dissipates heat into an environment apart from the medium by a heat sink thermally coupled to the heat extraction device; and heat from the medium is dissipated into the heat sink by a first thermal interface material thermally coupling the heat sink to the medium.
    Type: Application
    Filed: October 22, 2004
    Publication date: April 27, 2006
    Applicant: Research Triangle Insitute
    Inventors: Rama Venkatasubramanian, Randall Alley, Pratima Addepalli, Anil Reddy, Edward Siivola, Brooks O'Quinn, Kip Coonley, John Posthill, Thomas Colpitts
  • Patent number: 6722140
    Abstract: A cascade thermoelectric cooler designed to cool to cryogenic temperatures of 30 to 120 K integrates high performance\high-ZT BixSb2−xTe3 and Bi2Te3−xSe3-based super-lattice-structure thin-film thermoelectric devices with a bulk-material based thermoelectric cooler including plural cascaded cold stages with each successive cascaded cold stage able to cool to a progressively lower temperature. Each cold stage in the bulk-material thermoelectric cooler includes a heat source plate, a heat sink plate, a p-type thermoelectric, and a n-type thermoelectric. Moreover, the thin-film thermoelectric cooler can have multiple stages in which each stage contains a heat source plate, a heat sink plate, a p-type super-latticed thermoelectric element, and a n type super-latticed thermoelectric element.
    Type: Grant
    Filed: January 13, 2003
    Date of Patent: April 20, 2004
    Assignee: Research Triangle Institute
    Inventor: Rama Venkatasubramanian
  • Publication number: 20030230332
    Abstract: A thermoelectric device and method of manufacturing the device, where thermoelectric elements of opposite conductivity type are located on respective opposing sides of a heat source member. Heat sinks are disposed on opposite sides of the thermoelectric elements. Peltier metal contacts are positioned between the thermoelectric elements and each of the heat source member and heat sinks. A plurality of devices may be arranged together in a thermally parallel, electrically series arrangement, or in a thermally parallel, electrically parallel arrangement. The arrangement of the elements allow the direction of current flow through the pairs of elements to be substantially the same as the direction of current flow through the metal contacts.
    Type: Application
    Filed: April 15, 2003
    Publication date: December 18, 2003
    Applicant: Research Triangle Institute
    Inventors: Rama Venkatasubramanian, Edward P. Siivola
  • Patent number: 6662570
    Abstract: A cascade thermoelectric cooler designed to cool to cryogenic temperatures of 30 to 120 K integrates high performance\high-ZT BixSb2−xTe3 and Bi2Te3−xSe3-based super-lattice-structure thin-film thermoelectric devices with a bulk-material based thermoelectric cooler including plural cascaded cold stages with each successive cascaded cold stage able to cool to a progressively lower temperature. Each cold stage in the bulk-material thermoelectric cooler includes a heat source plate, a heat sink plate, a p-type thermoelectric, and a n-type thermoelectric. Moreover, the thin-film thermoelectric cooler can have multiple stages in which each stage contains a heat source plate, a heat sink plate, a p-type super-latticed thermoelectric element, and a n type super-latticed thermoelectric element.
    Type: Grant
    Filed: September 9, 2002
    Date of Patent: December 16, 2003
    Assignee: Research Triangle Institute
    Inventor: Rama Venkatasubramanian
  • Publication number: 20030131609
    Abstract: A cascade thermoelectric cooler designed to cool to cryogenic temperatures of 30 to 120 K integrates high performance\high-ZT BixSb2−xTe3 and Bi2Te3−xSe3-based super-lattice-structure thin-film thermoelectric devices with a bulk-material based thermoelectric cooler including plural cascaded cold stages with each successive cascaded cold stage able to cool to a progressively lower temperature. Each cold stage in the bulk-material thermoelectric cooler includes a heat source plate, a heat sink plate, a p-type thermoelectric, and a n-type thermoelectric. Moreover, the thin-film thermoelectric cooler can have multiple stages in which each stage contains a heat source plate, a heat sink plate, a p-type super-latticed thermoelectric element, and a n type super-latticed thermoelectric element.
    Type: Application
    Filed: January 13, 2003
    Publication date: July 17, 2003
    Applicant: Research Triangle Institute
    Inventor: Rama Venkatasubramanian
  • Publication number: 20030126865
    Abstract: A cascade thermoelectric cooler designed to cool to cryogenic temperatures of 30 to 120 K. integrates high performance\high-ZT BixSb2−xTe3 and Bi2Te3−xSe3 based super-lattice-structure thin-film thermoelectric devices with a bulk-material based thermoelectric cooler including plural cascaded cold stages with each successive cascaded cold stage able to cool to a progressively lower temperature. Each cold stage in the bulk-material thermoelectric cooler includes a heat source plate, a heat sink plate, a p-type thermoelectric, and a n-type thermoelectric. Moreover, the thin-film thermoelectric cooler can have multiple stages in which each stage contains a heat source plate, a heat sink plate, a p-type super-latticed thermoelectric element, and a n type super-latticed thermoelectric element.
    Type: Application
    Filed: September 9, 2002
    Publication date: July 10, 2003
    Applicant: Research Triangle Institute
    Inventor: Rama Venkatasubramanian
  • Publication number: 20030099279
    Abstract: A thermoelectric structure and device including at least first and second material systems having different lattice constants and interposed in contact with each other, and a physical interface at which the at least first and second material systems are joined with a lattice mismatch and at which structural integrity of the first and second material systems is substantially maintained. The at least first and second material systems have a charge carrier transport direction normal to the physical interface and preferably periodically arranged in a superlattice structure.
    Type: Application
    Filed: October 7, 2002
    Publication date: May 29, 2003
    Applicant: Research Triangle Insitute
    Inventors: Rama Venkatasubramanian, Edward Siivola, Thomas Colpitts, Brooks O'Quinn
  • Publication number: 20030100137
    Abstract: A method and structure for heat transport, cooling, sensing and power generation is described. A photonic bandgap structure (3) is employed to enhance emissive heat transport from heat sources such as integrated circuits (2) to heat spreaders (4). The photonic bandgap structure (3) is also employed to convert heat to electric power by enhanced emission absorption and to cool and sense radiation, such as infra-red radiation. These concepts may be applied to both heat loss and heat absorption, and may be applied to heat transport and absorption enhancement in a single device.
    Type: Application
    Filed: August 29, 2002
    Publication date: May 29, 2003
    Inventor: Rama Venkatasubramanian
  • Patent number: 6505468
    Abstract: A cascade thermoelectric cooler designed to cool to cryogenic temperatures of 30 to 120 K integrates high performance\high-ZT BixSb2−xTe3 and Bi2Te3−xSe3-based super-lattice-structure thin-film thermoelectric devices with a bulk-material based thermoelectric cooler including plural cascaded cold stages with each successive cascaded cold stage able to cool to a progressively lower temperature. Each cold stage in the bulk-material thermoelectric cooler includes a heat source plate, a heat sink plate, a p-type thermoelectric, and a n-type thermoelectric. Moreover, the thin-film thermoelectric cooler can have multiple stages in which each stage contains a heat source plate, a heat sink plate, a p-type super-latticed thermoelectric element, and a n type super-latticed thermoelectric element.
    Type: Grant
    Filed: March 21, 2001
    Date of Patent: January 14, 2003
    Assignee: Research Triangle Institute
    Inventor: Rama Venkatasubramanian
  • Publication number: 20020174660
    Abstract: A thermoelectric cooling and heating device including a substrate, a plurality of thermoelectric elements arranged on one side of the substrate and configured to perform at least one of selective heating and cooling such that each thermoelectric element includes a thermoelectric material, a Peltier contact contacting the thermoelectric material and forming under electrical current flow at least one of a heated junction and a cooled junction, and electrodes configured to provide current through the thermoelectric material and the Peltier contact. As such, the thermoelectric cooling and heating device selectively biases the thermoelectric elements to provide on one side of the thermolectric device a grid of localized heated or cooled junctions.
    Type: Application
    Filed: April 9, 2002
    Publication date: November 28, 2002
    Applicant: Research Triangle Institute
    Inventor: Rama Venkatasubramanian
  • Publication number: 20010052234
    Abstract: A cascade thermoelectric cooler designed to cool to cryogenic temperatures of 30 to 120 K integrates high performance\high-ZT BixSb2−xTe3 and Bi2Te3−xSe3-based super-lattice-structure thin-film thermoelectric devices with a bulk-material based thermoelectric cooler including plural cascaded cold stages with each successive cascaded cold stage able to cool to a progressively lower temperature. Each cold stage in the bulk-material thermoelectric cooler includes a heat source plate, a heat sink plate, a p-type thermoelectric, and a n-type thermoelectric. Moreover, the thin-film thermoelectric cooler can have multiple stages in which each stage contains a heat source plate, a heat sink plate, a p-type super-latticed thermoelectric element, and a n type super-latticed thermoelectric element.
    Type: Application
    Filed: March 21, 2001
    Publication date: December 20, 2001
    Applicant: Research Triangle Institute
    Inventor: Rama Venkatasubramanian
  • Patent number: 6300150
    Abstract: A termoelectric device and method for manufacturing the thermoelectric device.
    Type: Grant
    Filed: November 3, 1999
    Date of Patent: October 9, 2001
    Assignee: Research Triangle Institute
    Inventor: Rama Venkatasubramanian