Patents by Inventor Prasanth Kumar Nammalwar

Prasanth Kumar Nammalwar 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: 8865305
    Abstract: A method of making a core-shell phosphor is provided. The method comprises mixing a lanthanum phosphate (LaPO4) core with a shell precursor mixture comprising at least one compound of La, at least one compound of Ce, and at least one compound of Tb to form a core+shell precursor mixture, heating the core+shell precursor mixture to a temperature in a range from about 900° C. to about 1200° C. with an inorganic flux material in presence of a reductant to provide a heated core+shell precursor mixture, cooling the heated core+shell precursor mixture to ambient temperature to provide a product core-shell phosphor dispersed in the inorganic flux material; and separating the product core-shell phosphor from the inorganic flux material.
    Type: Grant
    Filed: June 16, 2010
    Date of Patent: October 21, 2014
    Assignee: General Electric Company
    Inventors: Digamber Gurudas Porob, Alok Mani Srivastava, Holly Ann Comanzo, Gopi Chandran Ramachandran, Prasanth Kumar Nammalwar
  • Publication number: 20140264418
    Abstract: A process for synthesizing a color stable Mn4+ doped phosphor includes contacting a precursor of formula I, in gaseous form at an elevated temperature with a fluorine-containing oxidizing agent to form the color stable Mn4+ doped phosphor Ax[MFy]:Mn4+??I wherein A is Li, Na, K, Rb, Cs, NR4 or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Hf, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; R is H, lower alkyl, or a combination thereof; x is the absolute value of the charge of the [MFy] ion; and y is 5, 6 or 7.
    Type: Application
    Filed: March 13, 2014
    Publication date: September 18, 2014
    Applicant: GENERAL ELECTRIC COMPANY
    Inventors: James Edward Murphy, Anant Achyut Setlur, Florencio Garcia, Robert Joseph Lyons, Ashfaqul Islam Chowdhury, Nagaveni Karkada, Prasanth Kumar Nammalwar
  • Publication number: 20140268655
    Abstract: A color stable Mn4+ doped phosphor of formula I, Ax[MFy]:Mn4+??I wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Hf, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; x is the absolute value of the charge of the [MFy] ion; y is 5, 6 or 7; and wherein % intensity loss of the phosphor after exposure to light flux of at least 80 w/cm2 at a temperature of at least 50° C. for at least 21 hours is ?4%.
    Type: Application
    Filed: May 23, 2014
    Publication date: September 18, 2014
    Applicant: GENERAL ELECTRIC COMPANY
    Inventors: James Edward Murphy, Anant Achyut Setlur, Florencio Garcia, Robert Joseph Lyons, Ashfaqul Islam Chowdhury, Nagaveni Karkada, Prasanth Kumar Nammalwar
  • Publication number: 20140231857
    Abstract: A phosphor material is presented that includes a blend of a first phosphor, a second phosphor and a third phosphor. The first phosphor includes a composition having a general formula of RE2?yM1+yA2?yScySin-wGewO12+?:Ce3+ wherein RE is selected from a lanthanide ion or Y3+, where M is selected from Mg, Ca, Sr or Ba, A is selected from Mg or Zn and where 0?y?2, 2.5?n?3.5, 0?w?1, and ?1.5???1.5. The second phosphor includes a complex fluoride doped with manganese (Mn4+), and the third phosphor include a phosphor composition having an emission peak in a range from about 520 nanometers to about 680 nanometers. A lighting apparatus including such a phosphor material is also presented. The light apparatus includes a light source in addition to the phosphor material.
    Type: Application
    Filed: September 20, 2012
    Publication date: August 21, 2014
    Applicant: GENERAL ELECTRIC COMPANY
    Inventors: Prasanth Kumar Nammalwar, Digamber Gurudas Porob, Anant Achyut Setlur, Satya Kishore Manepalli
  • Publication number: 20140178569
    Abstract: A method for making coated zinc silicate phosphor, the method includes the steps of combining a zinc silicate with a rare earth compound under aqueous conditions and removing the water from a product of the combination to form a powder. The powder is fired to form a coated zinc silicate phosphor.
    Type: Application
    Filed: December 20, 2013
    Publication date: June 26, 2014
    Inventors: PRASANTH KUMAR NAMMALWAR, ALOK MANI SRIVASTAVA, SWARNAGOWRI ADDEPALLI, DIGAMBER GURUDAS POROB, WILLIAM ERWIN COHEN, William Winder BEERS
  • Patent number: 8703016
    Abstract: A phosphor material is presented that includes a blend of a first phosphor, a second phosphor and a third phosphor. The first phosphor includes a composition having a general formula of ((Sr1?zMz)1?(x+w)AwCex)3(Al1?ySiy)O4+y+3(x?w)F1?y?3(x?w), wherein 0<x?0.10, 0?y?0.5, 0?z?0.5, 0?w?x, A comprises Li, Na, K, or Rb; and M comprises Ca, Ba, Mg, Zn, or Sn. The second phosphor includes a complex fluoride doped with manganese (Mn4+), and the third phosphor include a phosphor composition having an emission peak in a range from about 520 nanometers to about 680 nanometers. A lighting apparatus including such a phosphor material is also presented. The light apparatus includes a light source in addition to the phosphor material.
    Type: Grant
    Filed: June 28, 2011
    Date of Patent: April 22, 2014
    Assignee: General Electric Company
    Inventors: Prasanth Kumar Nammalwar, Anant Achyut Setlur, Digamber Gurudas Porob, Satya Kishore Manepalli
  • Patent number: 8282703
    Abstract: A method for recovering at least one rare earth element from a phosphor is presented. The method includes a halogenation step (a) and a reduction step (b). The phosphor is first halogenated in a molten salt to convert at least one rare earth constituent contained therein to a soluble rare earth halide. Then, the rare earth halide in the molten salt can be reduced, to convert the rare earth halide to a rare earth element in its elemental state. A method for individually recovering multiple rare earth elements from a phosphor is also presented.
    Type: Grant
    Filed: December 20, 2010
    Date of Patent: October 9, 2012
    Assignee: General Electric Company
    Inventors: Karthick Vilapakkam Gourishankar, Alok Mani Srivastava, Prasanth Kumar Nammalwar, Satya Kishore Manepalli
  • Publication number: 20120152062
    Abstract: A method for recovering at least one rare earth element from a phosphor is presented. The method includes a halogenation step (a) and a reduction step (b). The phosphor is first halogenated in a molten salt to convert at least one rare earth constituent contained therein to a soluble rare earth halide. Then, the rare earth halide in the molten salt can be reduced, to convert the rare earth halide to a rare earth element in its elemental state. A method for individually recovering multiple rare earth elements from a phosphor is also presented.
    Type: Application
    Filed: December 20, 2010
    Publication date: June 21, 2012
    Applicant: GENERAL ELECTRIC COMPANY
    Inventors: Karthick Vilapakkam Gourishankar, Alok Mani Srivastava, Prasanth Kumar Nammalwar, Satya Kishore Manepalli
  • Patent number: 8137645
    Abstract: A method of recovering a rare earth constituent from a phosphor is presented. The method can include a number of steps (a) to (d). In step (a), the phosphor is fired with an alkali material under conditions sufficient to decompose the phosphor into a mixture of oxides. A residue containing rare earth oxides is extracted from the mixture in step (b). In step (c), the residue is treated to obtain a solution, which comprises rare earth constituents in salt form. Rare earth constituents are separated from the solution in step (d).
    Type: Grant
    Filed: February 23, 2010
    Date of Patent: March 20, 2012
    Assignee: General Electric Company
    Inventors: Digamber Gurudas Porob, Alok Mani Srivastava, Prasanth Kumar Nammalwar, Gopi Chandran Ramachandran, Holly Ann Comanzo
  • Publication number: 20120019126
    Abstract: An oxynitride phosphor is presented. The oxynitride phosphor has a formula: ApBqOrNs: R such that A is barium or a combination of barium with at least one of Li, Na, K, Y, Sc, Be, Mg, Ca, Sr, Ba, Zn, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and Lu; B is silicon or a combination of silicon with at least one of Al, B, Ga, and Ge; R is europium or a combination of europium with at least one of Ce, Pr, Sm, Nd, Tb, Dy, Yb, Tm, Er, Ho, and Mn. p, q, r, s are numbers such that p is greater than about 2 and less than about 6, q is greater than about 8 and less than about 10, r is greater than about 0.1 and less than about 6, and s is greater than about 10 and less than about 15. The method of preparing the oxynitride phosphors and light emitting apparatus including the oxynitride phosphors are included.
    Type: Application
    Filed: July 22, 2010
    Publication date: January 26, 2012
    Applicant: GENERAL ELECTRIC COMPANY
    Inventors: Digamber Gurudas Porob, Anant Achyut Setlur, Prasanth Kumar Nammalwar, Shyamala Halady Subraya Bhat, Satya Kishore Manepalli, Dan Hancu
  • Publication number: 20110311823
    Abstract: A method of making a core-shell phosphor is provided. The method comprises mixing a lanthanum phosphate (LaPO4) core with a shell precursor mixture comprising at least one compound of La, at least one compound of Ce, and at least one compound of Tb to form a core+shell precursor mixture, heating the core+shell precursor mixture to a temperature in a range from about 900° C. to about 1200° C. with an inorganic flux material in presence of a reductant to provide a heated core+shell precursor mixture, cooling the heated core+shell precursor mixture to ambient temperature to provide a product core-shell phosphor dispersed in the inorganic flux material; and separating the product core-shell phosphor from the inorganic flux material.
    Type: Application
    Filed: June 16, 2010
    Publication date: December 22, 2011
    Applicant: GENERAL ELECTRIC COMPANY
    Inventors: Digamber Gurudas Porob, Alok Mani Srivastava, Holly Ann Comanzo, Gopi Chandran Ramachandran, Prasanth Kumar Nammalwar
  • Publication number: 20110255265
    Abstract: A phosphor material is presented that includes a blend of a first phosphor, a second phosphor and a third phosphor. The first phosphor includes a composition having a general formula of ((Sr1?zMz)1?(x+w)AwCex)3(Al1?ySiy)O4+y+3(x?w)F1?y?3(x?w), wherein 0<x?0.10, 0?y?0.5, 0?z?0.5, 0?w?x, A comprises Li, Na, K, or Rb; and M comprises Ca, Ba, Mg, Zn, or Sn. The second phosphor includes a complex fluoride doped with manganese (Mn4+), and the third phosphor include a phosphor composition having an emission peak in a range from about 520 nanometers to about 680 nanometers. A lighting apparatus including such a phosphor material is also presented. The light apparatus includes a light source in addition to the phosphor material.
    Type: Application
    Filed: June 28, 2011
    Publication date: October 20, 2011
    Applicant: GENERAL ELECTRIC COMPANY
    Inventors: Prasanth Kumar Nammalwar, Anant Achyut Setlur, Digamber Gurudas Porob, Satya Kishore Manepalli
  • Publication number: 20110206580
    Abstract: A method of recovering a rare earth constituent from a phosphor is presented. The method can include a number of steps (a) to (d). In step (a), the phosphor is fired with an alkali material under conditions sufficient to decompose the phosphor into a mixture of oxides. A residue containing rare earth oxides is extracted from the mixture in step (b). In step (c), the residue is treated to obtain a solution, which comprises rare earth constituents in salt form. Rare earth constituents are separated from the solution in step (d).
    Type: Application
    Filed: February 23, 2010
    Publication date: August 25, 2011
    Applicant: GENERAL ELECTRIC COMPANY
    Inventors: Digamber Gurudas Porob, Alok Mani Srivastava, Prasanth Kumar Nammalwar, Gopi Chandran Ramachandran, Holly Ann Comanzo
  • Patent number: 7857994
    Abstract: Phosphor compositions, blends thereof and light emitting devices including white light emitting LED based devices, and backlights, based on such phosphor compositions. The devices include a light source and a phosphor material as described. Also disclosed are phosphor blends including such a phosphor and devices made therefrom.
    Type: Grant
    Filed: May 30, 2007
    Date of Patent: December 28, 2010
    Assignee: GE Lighting Solutions, LLC
    Inventors: Anant Achyut Setlur, Oltea Puica Siclovan, Prasanth Kumar Nammalwar, Ramesh Rao Sathyanarayan, Digamber G. Porob, Ramachandran Gopi Chandran, William Jordan Heward, Emil Vergilov Radkov, Linda Jane Valyou Briel
  • Patent number: 7652415
    Abstract: An electron emissive material comprises an alkaline earth metal halide composition and operable to emit electrons on excitation. A lamp including an envelope, an electrode including an alkaline earth metal halide electron emissive material and a discharge material, is also disclosed.
    Type: Grant
    Filed: October 20, 2005
    Date of Patent: January 26, 2010
    Assignee: General Electric Company
    Inventors: Gopi Chandran Ramachandran, Alok Mani Srivastava, Timothy John Sommerer, Suchismita Sanyal, Prasanth Kumar Nammalwar, Holly Ann Comanzo, William Winder Beers, Madras Venugopal Shankar
  • Publication number: 20080296596
    Abstract: Phosphor compositions, blends thereof and light emitting devices including white light emitting LED based devices, and backlights, based on such phosphor compositions. The devices include a light source and a phosphor material as described. Also disclosed are phosphor blends including such a phosphor and devices made therefrom.
    Type: Application
    Filed: May 30, 2007
    Publication date: December 4, 2008
    Inventors: Anant Achyut Setlur, Oltea Puica Siclovan, Prasanth Kumar Nammalwar, Ramesh Rao Sathyanarayan, Digamber G. Porob, Ramachandran Gopi Chandran, William Jordan Heward, Emil Vergilov Radkov, Linda Jane Valyou Briel