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).
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Patent number: 8865305Abstract: 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: GrantFiled: June 16, 2010Date of Patent: October 21, 2014Assignee: General Electric CompanyInventors: Digamber Gurudas Porob, Alok Mani Srivastava, Holly Ann Comanzo, Gopi Chandran Ramachandran, Prasanth Kumar Nammalwar
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Publication number: 20140264418Abstract: 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: ApplicationFiled: March 13, 2014Publication date: September 18, 2014Applicant: GENERAL ELECTRIC COMPANYInventors: James Edward Murphy, Anant Achyut Setlur, Florencio Garcia, Robert Joseph Lyons, Ashfaqul Islam Chowdhury, Nagaveni Karkada, Prasanth Kumar Nammalwar
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Publication number: 20140268655Abstract: 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: ApplicationFiled: May 23, 2014Publication date: September 18, 2014Applicant: GENERAL ELECTRIC COMPANYInventors: James Edward Murphy, Anant Achyut Setlur, Florencio Garcia, Robert Joseph Lyons, Ashfaqul Islam Chowdhury, Nagaveni Karkada, Prasanth Kumar Nammalwar
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Publication number: 20140231857Abstract: 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: ApplicationFiled: September 20, 2012Publication date: August 21, 2014Applicant: GENERAL ELECTRIC COMPANYInventors: Prasanth Kumar Nammalwar, Digamber Gurudas Porob, Anant Achyut Setlur, Satya Kishore Manepalli
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Publication number: 20140178569Abstract: 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: ApplicationFiled: December 20, 2013Publication date: June 26, 2014Inventors: PRASANTH KUMAR NAMMALWAR, ALOK MANI SRIVASTAVA, SWARNAGOWRI ADDEPALLI, DIGAMBER GURUDAS POROB, WILLIAM ERWIN COHEN, William Winder BEERS
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Patent number: 8703016Abstract: 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: GrantFiled: June 28, 2011Date of Patent: April 22, 2014Assignee: General Electric CompanyInventors: Prasanth Kumar Nammalwar, Anant Achyut Setlur, Digamber Gurudas Porob, Satya Kishore Manepalli
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Patent number: 8282703Abstract: 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: GrantFiled: December 20, 2010Date of Patent: October 9, 2012Assignee: General Electric CompanyInventors: Karthick Vilapakkam Gourishankar, Alok Mani Srivastava, Prasanth Kumar Nammalwar, Satya Kishore Manepalli
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Publication number: 20120152062Abstract: 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: ApplicationFiled: December 20, 2010Publication date: June 21, 2012Applicant: GENERAL ELECTRIC COMPANYInventors: Karthick Vilapakkam Gourishankar, Alok Mani Srivastava, Prasanth Kumar Nammalwar, Satya Kishore Manepalli
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Patent number: 8137645Abstract: 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: GrantFiled: February 23, 2010Date of Patent: March 20, 2012Assignee: General Electric CompanyInventors: Digamber Gurudas Porob, Alok Mani Srivastava, Prasanth Kumar Nammalwar, Gopi Chandran Ramachandran, Holly Ann Comanzo
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Publication number: 20120019126Abstract: 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: ApplicationFiled: July 22, 2010Publication date: January 26, 2012Applicant: GENERAL ELECTRIC COMPANYInventors: Digamber Gurudas Porob, Anant Achyut Setlur, Prasanth Kumar Nammalwar, Shyamala Halady Subraya Bhat, Satya Kishore Manepalli, Dan Hancu
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Publication number: 20110311823Abstract: 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: ApplicationFiled: June 16, 2010Publication date: December 22, 2011Applicant: GENERAL ELECTRIC COMPANYInventors: Digamber Gurudas Porob, Alok Mani Srivastava, Holly Ann Comanzo, Gopi Chandran Ramachandran, Prasanth Kumar Nammalwar
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Publication number: 20110255265Abstract: 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: ApplicationFiled: June 28, 2011Publication date: October 20, 2011Applicant: GENERAL ELECTRIC COMPANYInventors: Prasanth Kumar Nammalwar, Anant Achyut Setlur, Digamber Gurudas Porob, Satya Kishore Manepalli
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Publication number: 20110206580Abstract: 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: ApplicationFiled: February 23, 2010Publication date: August 25, 2011Applicant: GENERAL ELECTRIC COMPANYInventors: Digamber Gurudas Porob, Alok Mani Srivastava, Prasanth Kumar Nammalwar, Gopi Chandran Ramachandran, Holly Ann Comanzo
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Patent number: 7857994Abstract: 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: GrantFiled: May 30, 2007Date of Patent: December 28, 2010Assignee: GE Lighting Solutions, LLCInventors: 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
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Patent number: 7652415Abstract: 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: GrantFiled: October 20, 2005Date of Patent: January 26, 2010Assignee: General Electric CompanyInventors: Gopi Chandran Ramachandran, Alok Mani Srivastava, Timothy John Sommerer, Suchismita Sanyal, Prasanth Kumar Nammalwar, Holly Ann Comanzo, William Winder Beers, Madras Venugopal Shankar
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Publication number: 20080296596Abstract: 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: ApplicationFiled: May 30, 2007Publication date: December 4, 2008Inventors: 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