Patents by Inventor Uttam Shyamalindu Ghoshal

Uttam Shyamalindu Ghoshal 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: 6598403
    Abstract: A thermoelectric cooling system integrating quantum cold point connections with lateral thermoelectric element formation. A preferred system has an n-type and p-type thermoelectric element, each connected to a common conducting section. The thermoelectric elements are each tapered at the end where they contact the common conducting section. The thermoelectric elements preferably all occupy substantially the same plane as each other and as the common conducting section.
    Type: Grant
    Filed: April 11, 2002
    Date of Patent: July 29, 2003
    Assignee: International Business Machines Corporation
    Inventor: Uttam Shyamalindu Ghoshal
  • Patent number: 6597544
    Abstract: A read/write head cooling system for use in a magnetic storage device, such as, for example, a hard disk drive is provided. In one embodiment, a thermally conducting patterned cold plate is thermally situated between a write coil and a read sensor of the read/write head. A microcooler, such as, for example, a thermoelectric cooler, is thermally coupled to the cold plate. A hot plate of one or more heat dissipation elements, such as, for example, copper posts, is thermally coupled to the hot side of the microcooler. The write coils of the read/write head are actively cooled by the microcooler to reduce the temperature of the write coil and read sensor in the head below that attainable with passive mechanisms.
    Type: Grant
    Filed: December 11, 2000
    Date of Patent: July 22, 2003
    Assignee: International Business Machines Corporation
    Inventor: Uttam Shyamalindu Ghoshal
  • Patent number: 6595004
    Abstract: Apparatus and methods for performing switching of heat flow in magnetic refrigeration systems are provided. In one embodiment, microelectromechanical (MEM) switches are provided for switching from a heat absorption phase and a heat rejection phase of a magnetic refrigeration cycle. In other embodiments, these MEM switches are replaced by thermoelectric switches. The thermoelectric switches operate such that an “on” state is defined as heat flow being allowed by virtue of the thermal conductivity of the thermoelectric switch. An “off” state is defined as a net zero heat flow through the thermoelectric switch obtained by providing a current that is just sufficient to offset the heat flow through the thermoelectric switch due to its thermal conductivity. In some embodiments, the thermoelectric switches are “directly coupled” thermoelectric switches, meaning that they are energized by a direct electrical coupling to a current source.
    Type: Grant
    Filed: April 19, 2002
    Date of Patent: July 22, 2003
    Assignee: International Business Machines Corporation
    Inventor: Uttam Shyamalindu Ghoshal
  • Patent number: 6588215
    Abstract: Apparatus and methods for performing switching of heat flow in magnetic refrigeration systems are provided. In one embodiment, microelectromechanical (MEM) switches are provided for switching from a heat absorption phase and a heat rejection phase of a magnetic refrigeration cycle. In other embodiments, these MEM switches are replaced by thermoelectric switches. The thermoelectric switches operate such that an “on” state is defined as heat flow being allowed by virtue of the thermal conductivity of the thermoelectric switch. An “off” state is defined as a net zero heat flow through the thermoelectric switch obtained by providing a current that is just sufficient to offset the heat flow through the thermoelectric switch due to its thermal conductivity. In some embodiments, the thermoelectric switches are “directly coupled” thermoelectric switches, meaning that they are energized by a direct electrical coupling to a current source.
    Type: Grant
    Filed: April 19, 2002
    Date of Patent: July 8, 2003
    Assignee: International Business Machines Corporation
    Inventor: Uttam Shyamalindu Ghoshal
  • Patent number: 6588217
    Abstract: An apparatus for cooling selected elements within an integrated circuit, such as active transistors or passive circuit elements used in a radio frequency integrated circuit is provided. In one embodiment, the cooling apparatus includes a cold plate thermally coupled to the region proximate the integrated circuit element, a thermoelectric cooler thermally coupled to the cold plate; and a hot plate thermally coupled to the thermoelectric cooler. Heat is removed from the integrated circuit element through the cold plate and transmitted to the hot plate through the thermoelectric cooler. In one form, the hot plate is located or coupled to an exterior surface of an integrated circuit, such that heat transmitted to the ambient from the integrated circuit element is dissipated into the atmosphere surrounding the integrated circuit. In another form, the hot plate is embedded in the integrated circuit substrate to locally cool elements of the integrated circuit while dumping the heat into the substrate.
    Type: Grant
    Filed: December 11, 2000
    Date of Patent: July 8, 2003
    Assignee: International Business Machines Corporation
    Inventor: Uttam Shyamalindu Ghoshal
  • Patent number: 6588216
    Abstract: Apparatus and methods for performing switching of heat flow in magnetic refrigeration systems are provided. In one embodiment, microelectromechanical (MEM) switches are provided for switching from a heat absorption phase and a heat rejection phase of a magnetic refrigeration cycle. In other embodiments, these MEM switches are replaced by thermoelectric switches. The thermoelectric switches operate such that an “on” state is defined as heat flow being allowed by virtue of the thermal conductivity of the thermoelectric switch. An “off” state is defined as a net zero heat flow through the thermoelectric switch obtained by providing a current that is just sufficient to offset the heat flow through the thermoelectric switch due to its thermal conductivity. In some embodiments, the thermoelectric switches are “directly coupled” thermoelectric switches, meaning that they are energized by a direct electrical coupling to a current source.
    Type: Grant
    Filed: April 19, 2002
    Date of Patent: July 8, 2003
    Assignee: International Business Machines Corporation
    Inventor: Uttam Shyamalindu Ghoshal
  • Publication number: 20030111516
    Abstract: A method for forming a thermoelement for a thermoelectric cooler is provided. In one embodiment a first substrate having a plurality of pointed tips separated by valleys wherein the substrate is covered by a metallic layer, portions of the metallic layer is covered by an insulator, and other portions of the metallic layer are exposed is formed. The other portions of the metallic layer that are exposed are covered with a thermoelectric material overcoat. A second substrate of thermoelectric material is then fused to the pointed tip side of the first substrate by, for example, heating the back of the first substrate to melt the thermoelectric material overcoat or by passing current through the pointed tips to induce Joule heating and thereby melt the thermoelectric material overcoat.
    Type: Application
    Filed: December 13, 2001
    Publication date: June 19, 2003
    Applicant: International Business Machines Corporation
    Inventor: Uttam Shyamalindu Ghoshal
  • Publication number: 20030113950
    Abstract: A method and system for forming a thermoelement for a thermoelectric cooler is provided. In one embodiment a substrate having a plurality of pointed tips covered by a metallic layer is formed. Portions of the metallic layer are covered by an insulator and other portions of the metallic layer are exposed. Next, a patterned layer of thermoelectric material is formed by depositions extending from the exposed portions of the metallic layer in the presence of a deposition mask. Finally, a metallic layer is formed to selectively contact the patterned layer of thermoelectric material.
    Type: Application
    Filed: December 13, 2001
    Publication date: June 19, 2003
    Applicant: International Business Machines Corp.
    Inventors: Emanuel Israel Cooper, Steven Alan Cordes, David R. Dimilia, Bruce Bennett Doris, James Patrick Doyle, Uttam Shyamalindu Ghoshal, Robin Altman Wanner
  • Publication number: 20030112844
    Abstract: A scanning heat flow probe for making quantitative measurements of heat flow through a device under test is provided. In one embodiment the scanning heat flow probe includes an electric current conductor in a cantilever beam connected to a probe tip and coupled to two voltmeter leads. The probe also includes two thermocouple junctions in the cantilever beam electrically isolated from the electric current conductor and the two voltmeter leads. Heat flow is derived quantitatively using only voltage and current measurements. In other forms, the invention relates to the calibration of scanning heat flow probes through a method involving interconnected probes, and relates to the minimization of heat flow measurement uncertainty by probe structure design practices.
    Type: Application
    Filed: December 17, 2001
    Publication date: June 19, 2003
    Applicant: International Business Machines Corporation
    Inventors: Steven Alan Cordes, David R. DiMilia, James Patrick Doyle, Matthew James Farinelli, Snigdha Ghoshal, Uttam Shyamalindu Ghoshal, Chandler Todd McDowell, Li Shi
  • Patent number: 6535342
    Abstract: A method of writing data onto magnetic thin film media commonly employed in magnetic disk drives at sub-ambient temperatures is disclosed. The method employs a thin film capacitor having a magnetoelectric element as its dielectric in a GMR read/write head to produce magnetic fields. To get the maximum magnetic field from the thin film capacitor, the thin-film capacitor is cooled via a thermoelectric cooling device present in the GMR read/write head of the magnetic disk drive. The magnetic field produced by the thermoelectrically cooled thin film capacitor structure is capable of writing data onto magnetic media with increased bit densities or coercivity.
    Type: Grant
    Filed: December 9, 1999
    Date of Patent: March 18, 2003
    Assignee: International Business Machines Corporation
    Inventor: Uttam Shyamalindu Ghoshal
  • Patent number: 6494048
    Abstract: A thermoelectric cooler and a system and method for fabricating the thermoelectric cooler are provided. In one embodiment, the thermoelectric cooler includes a first magnetic element, a second magnetic element composed of magnetic or magnetically susceptible material, a first thermoelectric sub-component, and a second thermoelectric sub-component. The first thermoelectric sub-component and the second thermoelectric sub-component are situated between the first and second magnetic elements. The first and second magnetic elements are selected such that a compressive force is exerted on the first and second thermoelectric elements. The magnetic elements are selected and adjusted in magnetic attraction such that the force exerted on the first and second thermoelectric elements establishes and maintains a contact of selected pressure between the first and second thermoelectric sub-components.
    Type: Grant
    Filed: April 11, 2002
    Date of Patent: December 17, 2002
    Assignee: International Business Machines Corporation
    Inventors: Uttam Shyamalindu Ghoshal, Chandler Todd McDowell
  • Patent number: 6487515
    Abstract: A method and apparatus for measuring and characterizing microscopic thermoelectric material samples using scanning microscopes. The method relies on concurrent thermal and electrical measurements using scanning thermal probes, and extends the applicability of scanning thermal microscopes (SThMs) to the characterization of thermoelectric materials. The probe makes use of two thermocouples to measure voltages at the tip and base of a cone tip of the probe. From these voltages, and from a voltage measured across the sample material, the Seebeck coefficient, thermal conductivity and resistance of the sample material can be accurately determined.
    Type: Grant
    Filed: August 18, 2000
    Date of Patent: November 26, 2002
    Assignee: International Business Machines Corporation
    Inventor: Uttam Shyamalindu Ghoshal
  • Publication number: 20020166839
    Abstract: A thermoelectric device with improved efficiency is provided. In one embodiment, the thermoelectric device includes a first thermoelement and a second thermoelement electrically coupled to the first thermoelement. An array of first tips are in close physical proximity to, but not necessarily in physical contact with, the first thermoelement at a first set of discrete points. An array of second tips are in close physical proximity to, but not necessarily in physical contact with, the second thermoelement at a second set of discrete points. The first and second conical are constructed entirely from metal, thus reducing parasitic resistances.
    Type: Application
    Filed: February 11, 2002
    Publication date: November 14, 2002
    Applicant: International Business Machines Corporation
    Inventors: Uttam Shyamalindu Ghoshal, Errol Wayne Robinson
  • Patent number: 6474074
    Abstract: An apparatus for dense chip packaging using heat pipes and thermoelectric coolers is provided. The apparatus includes an evaporator region, a condenser region, and a capillary region. The evaporator region includes one or more hot point elements used to transfer heat from a heat source to a transport fluid. The transport fluid changes state to a vapor when heat is applied to the transport fluid. The vapor travels to the condenser region via vapor channels and is condensed to a fluid once again by transferring heat from the vapor to a heat sink. The condensed fluid is then returned to the evaporator region by way of capillary forces and capillaries formed in a capillary structure. The capillaries formed in the capillary structure have a tree-like or fractal geometry. The apparatus may further include a flexible region that allows the apparatus to be bent around corners and edges.
    Type: Grant
    Filed: November 30, 2000
    Date of Patent: November 5, 2002
    Assignee: International Business Machines Corporation
    Inventor: Uttam Shyamalindu Ghoshal
  • Publication number: 20020160563
    Abstract: A method of fabricating an integrated circuit having air-gaps between interconnect levels. In a preferred embodiment, an integrated circuit is partially fabricated. The partially fabricated integrated circuit includes a top layer, interconnect structures having a cladding layer, dielectric layers and an etch stop layer resistant to certain first types of etchants. The top layer of the integrated circuit is etched with a second type of etchant. The dielectric layers are then etched with one of the first types of etchants until the etch stop layer is reached. Thus, portions of the interconnect structures are exposed to create interconnect islands surrounded by air. A cover is mechanically placed over the exposed interconnect islands to protect the integrated circuit from dust particles.
    Type: Application
    Filed: September 12, 2001
    Publication date: October 31, 2002
    Applicant: International Business Machines Corporation
    Inventor: Uttam Shyamalindu Ghoshal
  • Patent number: 6467275
    Abstract: A thermoelectric device is provided. In one embodiment, the thermoelectric device includes a first portion of a thermoelement and a second portion of the thermoelement. The first portion of the thermoelement is thermally coupled to a hot plate. The second portion of a thermoelement is thermally coupled to a cold plate. One of the first and second portions of the thermoelement comprises a plurality of tips and the other one of the first and second portions of the thermoelement comprises a substantially planar surface. The tips and the substantially planar surface are arranged in proximity such that the first and second portions of the thermoelement are electrically coupled.
    Type: Grant
    Filed: December 7, 2000
    Date of Patent: October 22, 2002
    Assignee: International Business Machines Corporation
    Inventor: Uttam Shyamalindu Ghoshal
  • Patent number: 6467951
    Abstract: A method and apparatus for measuring and characterizing microscopic thermoelectric material samples using scanning microscopes. The method relies on concurrent thermal and electrical measurements using scanning thermal probes, and extends the applicability of scanning thermal microscopes (SThMs) to the characterization of thermoelectric materials. The probe makes use of two thermocouples to measure voltages at the tip and base of a cone tip of the probe. From these voltages, and from a voltage measured across the sample material, the Seebeck coefficient, thermal conductivity and resistance of the sample material can be accurately determined.
    Type: Grant
    Filed: August 18, 2000
    Date of Patent: October 22, 2002
    Assignee: International Business Machines Corporation
    Inventor: Uttam Shyamalindu Ghoshal
  • Patent number: 6452740
    Abstract: An improved read/write head for use in computer hard drives is provided. In one embodiment, the read/write head includes first and second thermally conducting plates and a first and second stage of microcoolers. The second thermally conducting plate is thermally coupled to a read sensor of the read/write head. The second microcooler includes a hot plate and a cold plate, wherein the cold plate extends proximate the read sensor so as to cool the sensor to ambient or below temperatures. The first thermally conducting plate extends between the write coil and the read sensor in the read/write head and is thermally coupled to the hot plate of the second microcooler. The hot plate of the first microcooler is thermally coupled to one or more heat dissipation elements.
    Type: Grant
    Filed: December 11, 2000
    Date of Patent: September 17, 2002
    Assignee: International Business Machines Corporation
    Inventor: Uttam Shyamalindu Ghoshal
  • Patent number: 6446443
    Abstract: An apparatus for cooling selected elements within an integrated circuit, such as active transistors or passive circuit elements used in a radio frequency integrated circuit is provided. In one embodiment, the cooling apparatus includes a cold plate thermally coupled to the region proximate the integrated circuit element, a thermoelectric cooler thermally coupled to the cold plate; and a hot plate thermally coupled to the thermoelectric cooler. Heat is removed from the integrated circuit element through the cold plate and transmitted to the hot plate through the thermoelectric cooler. In one form, the hot plate is located or coupled to an exterior surface of an integrated circuit, such that heat transmitted to the ambient from the integrated circuit element is dissipated into the atmosphere surrounding the integrated circuit. In another form, the hot plate is embedded in the integrated circuit substrate to locally cool elements of the integrated circuit while dumping the heat into the substrate.
    Type: Grant
    Filed: December 11, 2000
    Date of Patent: September 10, 2002
    Assignee: International Business Machines Corporation
    Inventor: Uttam Shyamalindu Ghoshal
  • Publication number: 20020113289
    Abstract: Method and apparatus for thermal management of an integrated circuit. A semiconductor device includes an integrated circuit and an integrated thermoelectric cooler formed on a common substrate. A semiconductor device is fabricated by forming an integrated circuit on a front side of the substrate and forming an integrated thermoelectric cooler on a back side of the substrate. A first thermal sink of semiconductor material capable of absorbing heat from the integrated circuit is formed on the back side of the substrate. N-type thermoelectric elements are formed on contacts formed on the first thermal sink. P-type thermoelectric elements are formed on contacts formed on a second thermal sink of semiconductor material capable of dissipating heat. The p-type and n-type thermoelectric elements are bonded to the contacts on the first and second thermal sinks, respectively, by a flip-chip soldering process.
    Type: Application
    Filed: February 4, 2000
    Publication date: August 22, 2002
    Inventors: Michael James Cordes, Steven Alan Cordes, Uttam Shyamalindu Ghoshal, Errol Wayne Robinson, James Louis Speidell