Patents by Inventor Pabitra Datta
Pabitra Datta 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: 5405722Abstract: The invention relates to a method of electrophotographically manufacturing a luminescent screen assembly for a color CRT by utilizing materials whose volatilizable constituents are substantially completely baked-out in the same step in which the faceplate panel is frit sealed to the funnel of the tube envelope. This method eliminates a dedicated panel bake before frit sealing of the panel to the funnel.Type: GrantFiled: December 22, 1993Date of Patent: April 11, 1995Assignee: RCA Thomson Licensing Corp.Inventors: Pabitra Datta, Nitin V. DeSai, Ronald N. Friel, Eugene S. Poliniak
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Patent number: 5370952Abstract: The method of electrophotographically manufacturing a screen assembly on an interior surface of a faceplate panel for a color CRT, according to the present invention, includes the steps of sequentially coating the surface of the panel with a conductive solution to form a volatilizable organic conductive layer and then overcoating the conductive layer with a photoconductive solution to form a volatilizable organic photoconductive layer. The conductive layer, comprising a quaternary ammonium polyelectrolyte and a surfactant, provides an electrode for the photoconductive layer and has improved electrical and physical properties compared to prior conductive layers.Type: GrantFiled: December 22, 1993Date of Patent: December 6, 1994Assignee: RCA Thomson Licensing Corp.Inventors: Pabitra Datta, Nitin V. DeSai, Ronald N. Friel, Eugene S. Poliniak
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Patent number: 5135826Abstract: The method of electrophotographically manufacturing a luminescent screen assembly on a substrate for use within a CRT, according to the present invention, includes the steps of: forming a conductive layer on the substrate; overcoating the conductive layer with a photoconductive solution comprising an organic polymeric material, a suitable photoconductive dye, a plasticizer and a solvent to form a photoconductive layer; and, then, establishing an electrostatic charge on the photoconductive layer. Selected areas of the photoconductive layer are exposed to visible light to affect the charge thereon, and the photoconductive layer is developed with charged screen structure material. The improved method utilizes a dialkyl phthalate plasticizer which is selected from the group consisting of dibutylphthalate (DBP), dioctylphthalate (DOP), and diundecylphthalate (DUP).Type: GrantFiled: April 29, 1991Date of Patent: August 4, 1992Assignee: RCA Thomson Licensing Corp.Inventors: Peter M. Ritt, Harry R. Stork, Pabitra Datta
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Patent number: 5132188Abstract: A method of electrophotographically manufacturing a luminescent screen on an interior concave surface of a CRT faceplate panel having a major axis with a first center of curvature and a minor axis with a second center of curvature, the method including the steps of utilizing a charging apparatus for uniformly charging a photoconductive layer disposed on the concave surface of the faceplate panel by providing a corona voltage from a corona generator to at least one corona charger which has an arcuately-shaped charging electrode, the corona charger has a center of curvature substantially concentric with a center of curvature of the concave surface of the panel, a support arm attached to the corona charger is pivotably located at the other center of curvature, the corona charger substantially conforms to, and is spaced from the photoconductive layer on the concave surface, and moving the corona charger across the concave surface.Type: GrantFiled: August 13, 1990Date of Patent: July 21, 1992Assignee: RCA Thomson Licensing Corp.Inventors: Pabitra Datta, George H. Riddle, Ronald N. Friel, Robert E. Simms, Carl C. Steinmetz
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Patent number: 5093217Abstract: An apparatus for electrophotographically manufacturing a luminescent screen assembly on a substrate for use within a CRT includes a developer for developing a photoconductive layer, having a latent image thereon, with a dry-powdered, triboelectrially-charged screen structure materials. The photoconductive layer overlies a conductive layer in contact with the substrate. A grid-developing electrode is located at a distance from the photoconductive layer that is large relative to the smallest dimension of the latent image. The electrode is biased with a suitable potential to influence the deposition of the charged screen structure materials onto the latent image on the photoconductive layer. A method for electrophotographically manufacturing the screen assembly utilizing the grid-developing electrode is also disclosed.Type: GrantFiled: October 11, 1989Date of Patent: March 3, 1992Assignee: RCA Thomson Licensing CorporationInventors: Pabitra Datta, Randall E. McCoy, Ronald N. Friel, John A. van Raalte, Wilber C. Stewart
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Patent number: 5083959Abstract: An apparatus for uniformly charging a photoconductive layer disposed on an interior, non-planar surface of a faceplate panel of a CRT during electrophotographic screen processing of the panel includes a corona generator having at least one corona charger and a mechanism for moving the corona charger across the non-planar surface of the faceplate panel. The corona charger substantially conforms to, and is spaced from the photoconductive layer on the non-planar, interior surface of the faceplate panel.Type: GrantFiled: August 13, 1990Date of Patent: January 28, 1992Assignee: RCA Thomson Licensing Corp.Inventors: Pabitra Datta, George H. N. Riddle, Ronald N. Friel, Robert E. Simms, Carl C. Steinmetz
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Patent number: 5012155Abstract: The method of surface-treating dry-powdered phosphor particles for use in manufacturing a viewing screen for a CRT to control the triboelectric charge characteristics of the phosphor particles includes the steps of dissolving a suitable quantity of a polymeric coupling agent in a suitable solvent to form a mixture, surface-treating the phosphor particles by adding them to the mixture to provide a coating of the coupling agent thereon, and then drying the surface-treated phosphor particles. The resultant dry-powdered surface-treated phosphor particles are used to make a luminescent viewing screen for a CRT. The coupling agent controls the triboelectric charge characteristics of the phosphor particles during the electrophotographic manufacturing of the screen.Type: GrantFiled: December 22, 1989Date of Patent: April 30, 1991Assignee: RCA Licensing Corp.Inventors: Pabitra Datta, Ronald N. Friel, Robert P. Thompson
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Patent number: 4975619Abstract: A method of surface-treating dry-powdered phosphor particles to control the triboelectric charge characteristics thereof includes the steps of providing the phosphor particles with a first coating of silica, dissolving a coupling agent selected from the group consisting of silanes and titanates in a suitable solvent to form a mixture, surface-coating the silica-coated phosphor particles with the mixture to provide a second coating of the coupling agent on the phosphor particles, filtering the surface-treated particles, rinsing the surface-treated particles with the solvent, and drying the surface-treated particles. The resultant dry-powdered surface-treated phosphor particles are used to make a luminescent viewing screen for a CRT. The coupling agent overlying the silica coating controls the triboelectric charging characteristics of the phosphor particles during the electrophotographic manufacturing of the screen.Type: GrantFiled: December 22, 1989Date of Patent: December 4, 1990Assignee: RCA Licensing Corp.Inventors: Pabitra Datta, Ronald N. Friel
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Patent number: 4921727Abstract: A method of surface-treating dry-powdered phosphor particles to control the triboelectric charge characteristics thereof includes the steps of providing the phosphor particles with a first coating of silica, dissolving a coupling agent selected from the group consisting of silanes and titanates in a suitable solvent to form a mixture, surface-coating the silica-coated phosphor particles with the mixture to provide a second coating of the coupling agent on the phosphor particles, filtering the surface-treated particles, rinsing the surface-treated particles with the solvent, and drying the surface-treated particles. The resultant dry-powdered surface-treated phosphor particles are used to make a luminescent viewing screen for a CRT. The coupling agent overlying the silica coating controls the triboelectric charging characteristics of the phosphor particles during the electrophotographic manufacturing of the screen.Type: GrantFiled: December 21, 1988Date of Patent: May 1, 1990Assignee: RCA Licensing CorporationInventors: Pabitra Datta, Ronald N. Friel
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Method of electrophotographically manufacturing a luminescent screen assembly for a cathode-ray-tube
Patent number: 4921767Abstract: The method of electrophotographically manufacturing a screen assembly on a substrate for use within a CRT, according to the present invention, includes the steps of sequentially coating a substrate with a conductive layer and an overcoating of a photoconductive layer, establishing an electrostatic charge on the photoconductive layer, and exposing selected areas of the photoconductive layer to visible light to affect the charge thereon. Then the photoconductive layer is developed with a charged screen structure material. The improved process utilizes a dry-powdered screen structure material having at least a surface charge control agent thereon to control the triboelectrical charging of the screen structure material.Type: GrantFiled: December 21, 1988Date of Patent: May 1, 1990Assignee: RCA Licensing Corp.Inventors: Pabitra Datta, Ronald N. Friel -
Patent number: 4561087Abstract: A video disc comprises a grooved disc having video information in the form of a surface relief pattern within the groove, the disc made from a plastic material containing finely divided conductive particles such that the bulk resistivity at 900 MHz is less than 500 ohm-centimeters.Type: GrantFiled: December 20, 1979Date of Patent: December 24, 1985Assignee: RCA CorporationInventors: Leonard P. Fox, Pabitra Datta, Dennis L. Matthies, Hirohisa Kawamoto
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Patent number: 4560601Abstract: High-density information records are lubricated with a methyl alkyl siloxane lubricant containing an effective amount of a donor-acceptor complex to reduce moisture sensitivity.Type: GrantFiled: July 31, 1984Date of Patent: December 24, 1985Assignee: RCA CorporationInventor: Pabitra Datta
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Patent number: 4512916Abstract: A conductive molding composition for the compression molding of high density information discs (video discs). The composition includes a polyvinylchloride-based resin containing sufficient carbon black particles to obtain a desired conductivity (bulk resistivity of about 500 ohm-cm at 900 mHz or less,) from about 1 to 5 weight percent of a stabilizer, from about 0.5 to 3 weight percent of a lubricant, from about 1 to 5 weight percent of a plasticizer and from about 0.1 to 1 weight percent of an organo-silicone compound having polar groups.Type: GrantFiled: December 27, 1982Date of Patent: April 23, 1985Assignee: RCA CorporationInventor: Pabitra Datta
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Patent number: 4455335Abstract: Capacitance electronic discs comprising conductive carbon-loaded PVC records are lubricated with a long chain polyalkylethylene lubricant containing 9-phenylstearyl alcohol as a dopant in an amount sufficient to reduce the moisture sensitivity of the discs.Type: GrantFiled: February 22, 1983Date of Patent: June 19, 1984Assignee: RCA CorporationInventors: Pabitra Datta, Eugene S. Poliniak
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Patent number: 4444820Abstract: 9-Phenylstearyl alcohol, when added to a fractionated methyl alkyl siloxane lubricant for capacitive electronic discs, improves the playback performance and surface quality of the disc.Type: GrantFiled: February 22, 1983Date of Patent: April 24, 1984Assignee: RCA CorporationInventors: Pabitra Datta, Eugene S. Poliniak
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Patent number: 4416807Abstract: Conductive information discs comprised of conductive particles such as carbon black dispersed in a stable thermoplastic material comprising a homopolymer of styrene, an acrylic acid ester, or a methacrylic acid ester, a copolymer of styrene and acrylonitrile, an acrylic acid ester, or a methacrylic acid ester, or mixtures thereof, is disclosed.Type: GrantFiled: October 14, 1981Date of Patent: November 22, 1983Assignee: RCA CorporationInventors: Pabitra Datta, Ronald N. Friel
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Patent number: 4410748Abstract: High density information records comprising a conductive carbon-loaded polyvinylchloride record are lubricated with a long chain polyalkylethylene containing a polar dopant substituted with a long chain alkyl group in amounts sufficient to reduce sensitivity of the records to moisture.Type: GrantFiled: February 1, 1982Date of Patent: October 18, 1983Assignee: RCA CorporationInventors: Pabitra Datta, Eugene S. Poliniak
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Patent number: 4390579Abstract: High density information discs comprising a conductive carbon-loaded polyvinylchloride disc are lubricated with a polyphenylene ether containing a polar dopant substituted with a long chain alkyl group in amounts sufficient to reduce surface tension of the polyphenylene ether to enable adequate wetting of the disc surface. The successful application of this doped lubricant provides the discs with excellent lubrication, highly resistant to oxidation, moisture and shear stress.Type: GrantFiled: June 17, 1982Date of Patent: June 28, 1983Assignee: RCA CorporationInventors: Pabitra Datta, Eugene S. Poliniak
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Patent number: 4389441Abstract: High density information records comprising a conductive carbon-loaded polyvinylchloride record are lubricated with a fractionated methyl alkyl siloxane lubricant which contains at least two dopants in an amount sufficient to reduce sensitivity of the records to moisture.Type: GrantFiled: February 1, 1982Date of Patent: June 21, 1983Assignee: RCA CorporationInventors: Pabitra Datta, Eugene S. Poliniak, Vladimir S. Ban
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Patent number: 4378310Abstract: An improved molding composition having a high thermal stability, including a vinyl chloride/vinyl acetate copolymer-based resin, sufficient finely divided conductive particles to obtain the desired conductivity, and from 3 to 20 weight percent of the modifying additive BLENDEX 586, which is a three-component blend of polyvinyl chloride, a graft copolymer of acrylonitrile, styrene and polybutadiene, and a copolymer of alpha-methyl styrene and acrylonitrile, as described in U.S. Pat. No. 3,053,800. High density information discs fabricated from this molding composition have improved dimensional stability and increased resistance to environmental temperature changes.Type: GrantFiled: July 28, 1980Date of Patent: March 29, 1983Assignee: RCA CorporationInventors: Pabitra Datta, Nestor A. Arroyo, Ronald N. Friel