Patents by Inventor Vaddi B. Reddy
Vaddi B. Reddy 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: 5582768Abstract: Electroluminescent phosphors having substantially increased luminance and maintenance over that of prior art electroluminescent phosphors may be made by (1) doping an inorganic intercalation compound having an atomic structure interspersed with vacant spaces, with selected activator ions capable of luminescent emission, and (2) introducing organic monomers or other conductive material into the vacant spaces of the atomic structure of the doped inorganic intercalation compound. The organic monomers may be polymerized in situ to form conductive polymers therein.Type: GrantFiled: October 24, 1995Date of Patent: December 10, 1996Assignee: Osram Sylvania, Inc.Inventors: Vaddi B. Reddy, Ronald E. Karam, Shellie K. Northrop
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Patent number: 5567351Abstract: Inorganic intercalation phosphors were made by doping an inorganic intercalation compound having an atomic structure interspersed with vacant spaces with selected activator ions capable of luminescent emission when excited by ultraviolet light and/or cathode rays.Type: GrantFiled: April 20, 1995Date of Patent: October 22, 1996Assignee: OSRAM Sylvania Inc.Inventors: Ru-Yi Qi, Ronald E. Karam, Vaddi B. Reddy, James R. Cox
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Patent number: 5531928Abstract: Electroluminescent phosphors having substantially increased luminance and maintenance over that of prior art electroluminescent phosphors may be made by (1) doping an inorganic intercalation compound having an atomic structure interspersed with vacant spaces, with selected activator ions capable of luminescent emission, and (2) introducing organic monomers or other conductive material into the vacant spaces of the atomic structure of the doped inorganic intercalation compound. The organic monomers may be polymerized in situ to form conductive polymers therein.Type: GrantFiled: May 9, 1995Date of Patent: July 2, 1996Assignee: Osram Sylvania Inc.Inventors: Ronald E. Karam, Vaddi B. Reddy, Shellie K. Northrop, Yan Zhang
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Patent number: 5489398Abstract: Electroluminescent phosphors having substantially increased luminance and maintenance over that of prior art electroluminescent phosphors may be made by (1) doping an inorganic intercalation compound having an atomic structure interspersed with vacant spaces, with selected activator ions capable of luminescent emission, and (2) introducing organic monomers or other conductive material into the vacant spaces of the atomic structure of the doped inorganic intercalation compound. The organic monomers may be polymerized in situ to form conductive polymers therein.Type: GrantFiled: December 6, 1993Date of Patent: February 6, 1996Assignee: Osram Sylvania Inc.Inventors: Vaddi B. Reddy, Ronald E. Karam, Shellie K. Northrop
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Patent number: 5380463Abstract: The brightness and particle size of a niobium-activated yttrium tantalate x-ray phosphor can be increased by the addition of either barium fluorosilicate or calcium fluorosilicate thereto.Type: GrantFiled: May 13, 1994Date of Patent: January 10, 1995Assignee: Osram Sylvania Inc.Inventors: Vaddi B. Reddy, Ha K. Cheung
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Patent number: 5306441Abstract: Electroluminescent phosphors having substantially increased luminance and maintenance over that of prior art electroluminescent phosphors may be made by (1) doping an inorganic intercalation compound having an atomic structure interspersed with vacant spaces, with selected activator ions capable of luminescent emission, and (2) introducing organic monomers or other conductive material into the vacant spaces of the atomic structure of the doped inorganic intercalation compound. The organic monomers may be polymerized in situ to form conductive polymers therein.Type: GrantFiled: February 1, 1993Date of Patent: April 26, 1994Assignee: GTE Products CorporationInventors: Vaddi B. Reddy, Ronald E. Karam, Shellie K. Northrop
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Patent number: 5112524Abstract: An unactivated yttrium tantalate phosphor, M'YTaO.sub.4, contains one or more additives of Sr, Rb and Al in order to improve brightness under X-radiation.Type: GrantFiled: July 19, 1991Date of Patent: May 12, 1992Assignee: GTE Products CorporationInventors: Vaddi B. Reddy, Ha K. Cheung
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Patent number: 4938890Abstract: A method of making a niobium activated yttrium tantalate x-ray phosphor using a lithium chloride-lithium sulfate eutectic flux is disclosed. The mole ratio of the flux is 46.5 mole percent lithium chloride to 53.5 mole percent lithium sulfate. Use of this flux improves phosphor brightness by up to 18%, reducing the x-ray dosage to the patient.Type: GrantFiled: February 20, 1990Date of Patent: July 3, 1990Assignee: GTE Products CorporationInventor: Vaddi B. Reddy
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Patent number: 4935161Abstract: A process is disclosed for preparing M' YTaO.sub.4 :Nb x-ray phosphor which comprises forming a uniform first mixture of Y.sub.2 O.sub.3, Ta.sub.2 O.sub.5, and Nb.sub.2 O.sub.5 in amounts equal to approximately the stoichiometric amounts to form the phosphor, milling with a flux of lithium chloride, the flux making up about 25% to 33% by weight of the mixture, firing the mixture in a furnace by heating to a temperature of about 1200.degree. C. to 1300.degree. C. at a heating rate of about 1.0.degree. C./minute to 1.5.degree. C./minute and maintaining the temperature for about 10 to 14 hours to react the components and produce a fired material containing luminescent material, cooling the material by turning off the heat and allowing the material to remain in the furnace until the temperature is no higher than about 300.degree. C., washing with deionized water, removing the wash water, drying, and classifying to obtain a -325 mesh particle size.Type: GrantFiled: October 5, 1989Date of Patent: June 19, 1990Assignee: GTE Products CorporationInventors: Vaddi B. Reddy, Ha Cheung
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Patent number: 4929385Abstract: A process is disclosed for preparing M' YTaO.sub.4 :Nb X-ray phosphor which comprises forming a uniform first mixture of Y.sub.2 O.sub.3, Ta.sub.2 O.sub.5, and Nb.sub.2 O.sub.5 in amounts equal to approximately the stoichiometric amounts to form the phosphor, milling with deionized water as the milling fluid, removing the water, forming a uniform second mixture of the first mixture and a flux which can be lithium sulfate, lithium chloride or a mix of lithium sulfate and potassium sulfate in a mole ratio of 80 to 20, the flux making up about 25% to 50% by weight of the second mixture, firing the second mixture in a furnace by heating to a temperature of about 1200.degree. C. to 1300.degree. C. at a heating rate of about 1.0.degree. C./minute to 1.5.degree. C./min.Type: GrantFiled: June 7, 1989Date of Patent: May 29, 1990Assignee: GTE Products CorporationInventor: Vaddi B. Reddy
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Patent number: 4929384Abstract: A process is disclosed for producing M' phase YTaO.sub.4 :Nb X-ray phosphor which comprises forming a mixture of the components Y.sub.2 O.sub.3, Ta.sub.2 O.sub.5, and Nb.sub.2 O.sub.5, and a flux which can be lithium chloride, lithium sulfate or a mix of lithium sulfate and potassium sulfate in a mole ratio of 80 to 20, the flux making up about 25% to 50% by weight of the mixture, the components being provided in an amount equal to approximately the stoichiometric amounts to form the phosphor, firing the mixture in a furnace by heating to a temperature of about 1200.degree. C. to 1300.degree. C. at a heating rate of about 1.0.degree. C./min. to 1.5.degree. C./min. and maintaining the temperature for about 10 to 14 hours to react the components and produce a fired material containing luminescent material, cooling the material by turning off the heat to the furnace and allowing the material to remain in the furnace until the temperature is no higher than about 300.degree. C.Type: GrantFiled: June 7, 1989Date of Patent: May 29, 1990Assignee: GTE Products CorporationInventor: Vaddi B. Reddy
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Patent number: 4929386Abstract: A process is disclosed for preparing a single phase M'YTaO.sub.4 :Nb X-ray phosphor which comprises firing a uniform milled mixture consisting essentially of the components of Y.sub.2 O.sub.3, Ta.sub.2 O.sub.5, and Nb.sub.2 O.sub.5 in an amount equal to the stoichiometric amounts to form the phosphor, with a flux consisting essentially of lithium sulfate and potassium sulfate in a mole ratio of about 80 to 20, wherein the flux makes up from about 25% to about 50% by weight of the mixture. The firing is done by heating in a furnace to a temperature of from about 1200.degree. C. to about 1300.degree. C. at a heating rate of from about 1.0.degree. C. per minute to about 1.5.degree. C. per minute and maintaining the temperature for about 10 to 14 hours to react the components and produce a fired material containing luminescent material.Type: GrantFiled: June 7, 1989Date of Patent: May 29, 1990Assignee: GTE Products CorporationInventor: Vaddi B. Reddy
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Patent number: 4925702Abstract: A process is disclosed for producing M' phase YTaO.sub.4 :Nb X-ray phosphor which comprises forming a mixture of components Y.sub.2 O.sub.3, Ta.sub.2 O.sub.5, and Nb.sub.2 O.sub.5, and a flux which can be lithium chloride, lithium sulfate or a mix of lithium sulfate and potassium sulfate in an 80 to 20 mole ratio, the flux making up about 25% to 50% by weight of the mixture, the components being provided in stoichiometric amounts to form the phosphor, firing the mixture in a furnace by heating to a temperature of about 1200.degree. C. to 1300.degree. C. at a heating rate of about 1.0.degree. C./min. to 1.5.degree. C./min. and maintaining the temperature for about 10 to 14 hours to react the components and produce luminescent material, cooling the material by turning off the heat to the furnace and allowing the material to remain therein until the temperature is no higher than about 300.degree. C.Type: GrantFiled: October 2, 1989Date of Patent: May 15, 1990Assignee: GTE Products CorporationInventor: Vaddi B. Reddy