Patents by Inventor George R. Chapman
George R. Chapman 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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Publication number: 20020161120Abstract: Extrusion processability of non-fluorinated melt-processable polymers is improved by introducing a fluoropolymer process aid by means whereby the weight average particle size of the fluoropolymer is greater than 2 microns as it reaches the extruder die entrance.Type: ApplicationFiled: September 17, 2001Publication date: October 31, 2002Inventors: George R. Chapman, Steven R. Oriani
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Patent number: 5959339Abstract: An array (41) is comprised of a plurality of radiation detectors (10, 10') each of which includes a first photoresponsive diode (D1) having an anode and a cathode that is coupled to an anode of a second photoresponsive diode (D2). The first photoresponsive diode responds to electromagnetic radiation within a first band of wavelengths and the second photoresponsive diode responds to electromagnetic radiation within a second band of wavelengths. Each radiation detector further includes a first electrical contact (26) that is conductively coupled to the anode of the first photoresponsive diode; a second electrical contact (28) that is conductively coupled to the cathode of the first photoresponsive diode and to the anode of the second photoresponsive diode; and a third electrical contact (30) that is conductively coupled to a cathode of each second photoresponsive diode of the array. The electrical contacts are coupled during operation to respective bias potentials.Type: GrantFiled: March 19, 1996Date of Patent: September 28, 1999Assignee: Raytheon CompanyInventors: George R. Chapman, Kenneth Kosai
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Patent number: 5581084Abstract: An array of dual-band HgCdTe radiation detectors (10) wherein individual detectors include a first layer (14) having a first type of electrical conductivity and a bandgap selected for absorbing radiation within a first spectral band. The radiation detectors also each include a second layer (16) overlying the first layer. The second layer has a second type of electrical conductivity that is opposite the first type of electrical conductivity. Each radiation detector further includes a third layer (18) overlying the second layer, the third layer having the first type of electrical conductivity and a bandgap selected for absorbing radiation within a second spectral band. The first and second spectral bands are selected from SWIR, MWIR, LWIR, and VLWIR. The first, second and third layers are contained within at least one mesa structure (10a, 10b) that supports on a top surface thereof a first electrical contact (24) to the first layer and a second electrical contact (28) to the third layer.Type: GrantFiled: June 7, 1995Date of Patent: December 3, 1996Assignee: Santa Barbara Research CenterInventors: George R. Chapman, Bonnie A. Baumgratz, Michael Ray
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Patent number: 5547761Abstract: Copolymers of tetrafluoroethylene (TFE) and hexafluoropropylene (HFP) having high HFP content and end-of-melting temperature, T.sub.m (end), as low as 200.degree. C. are disclosed. Exceptional performance as a processing aid in polyolefins results from having T.sub.m (end) of the TFE/HFP copolymer close to the processing temperature of the polyolefin. These TFE/HFP copolymers are soluble in fluorinated cyclic solvents. Copolymer/solvent systems copolymer at significant concentrations in selected solvents are fluid and stable at room temperature.Type: GrantFiled: June 1, 1995Date of Patent: August 20, 1996Assignee: E. I. Du Pont de Nemours and CompanyInventors: George R. Chapman, Jr., Richard A. Morgan, Charles W. Stewart, William H. Tuminello, John G. Van Alsten, Randall A. Vogel, Mark E. Wagman
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Patent number: 5464904Abstract: Copolymers of tetrafluoroethylene (TFE) and hexafluoropropylene (HFP) having high HFP content and end-of-melting temperature, T.sub.m (end), as low as 200.degree. C. are disclosed. Exceptional performance as a processing aid in polyolefins results from having T.sub.m (end) of the TFE/HFP copolymer close to the processing temperature of the polyolefin. These TFE/HFP copolymers are soluble in fluorinated cyclic solvents. Copolymer/solvent systems copolymer at significant concentrations in selected solvents are fluid and stable at room temperature.Type: GrantFiled: November 16, 1994Date of Patent: November 7, 1995Assignee: E. I. Du Pont de Nemours and CompanyInventors: George R. Chapman, Jr., Lewis E. Crenshaw, Rita S. McMinn, Richard A. Morgan, Donnan E. Priester, Charles W. Stewart, Robert E. Tarney
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Patent number: 5457331Abstract: A dual-band HgCdTe radiation detector (10) includes a four layer n-p.sup.+ -p-n.sup.+ structure, grown by LPE, upon a substrate (12). The four layers are, from a bottom layer next to the substrate to the surface: (a) a MWIR radiation responsive n-type absorbing layer (14); (b) a p.sup.+ cap layer (16); (c) a LWIR radiation responsive p-type layer (18); and (d) an n+ top layer (20). The n.sup.+ top layer has a compositional profile that is similar to the p-type cap layer. Operation of this structure involves biasing the top layer positive with respect to the bottom layer, which results in the collection of LWIR-generated electrons in the p-type layer. Biasing the top layer negative with respect to the bottom layer results in MWIR-generated holes being collected by the bottom n-p+ junction.Type: GrantFiled: April 8, 1993Date of Patent: October 10, 1995Assignee: Santa Barbara Research CenterInventors: Kenneth Kosai, George R. Chapman
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Patent number: 5266639Abstract: Copolymers of tetrafluoroethylene (TFE) and hexafluoropropylene (HFP) having high HFP content and end-of-melting temperature, T.sub.m (end), as low as 200.degree. C. are disclosed. Exceptional performance as a processing aid in polyolefins results from having T.sub.m (end) of the TFE/HFP copolymer close to the processing temperature of the polyolefin. These TFE/HFP copolymers are soluble in fluorinated cyclic solvents. Copolymer/solvent systems copolymer at significant concentrations in selected solvents are fluid and stable at room temperature.Type: GrantFiled: August 28, 1992Date of Patent: November 30, 1993Assignee: E. I. Du Pont de Nemours and CompanyInventors: George R. Chapman, Jr., Lewis E. Crenshaw, Rita S. McMinn, Richard A. Morgan, Donnan E. Priester, Charles W. Stewart, William H. Tuminello, Robert E. Tarney, John G. Van Alsten, Mark E. Wagman
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Patent number: 5132368Abstract: The subject invention provides a composition having excellent extrusion characteristics comprising a difficulty-melt-processible polymer and 0.002-0.5 wt. % of one or more fluoropolymer process aids wherein the fluoropolymer has a fluorine to carbon ratio of at least 1:2, is capable of forming a die-coating film under the prevailing conditions of extrusion temperature and pressure, and contains an effective amount of polar functional polymer chain end groups, --W, wherein --W is selected from --COF, --SO.sub.2 F, --SO.sub.3 M, --OSO.sub.3 M, --COOR, and --COOM, wherein R is C.sub.1-3 alkyl and M is hydrogen, a metal cation, preferably an alkali or alkaline earth metal cation, or a quaternary ammonium cation.Type: GrantFiled: September 3, 1991Date of Patent: July 21, 1992Assignee: E. I. Du Pont de Nemours and CompanyInventors: George R. Chapman, Jr., Donnan E. Priester, Charles W. Stewart, Robert E. Tarney
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Patent number: 5106911Abstract: An extrusion process for difficultly melt processible resins, for example, a difficultly-melt-processible hydrocarbon polymer, having improved processibility and having incorporated therein an elastomeric fluorocarbon copolymer, for example, an amorphous vinylidene fluoride copolymer, and a crystalline vinylidene fluoride polymer.Type: GrantFiled: July 15, 1991Date of Patent: April 21, 1992Assignee: E. I. Du Pont de Nemours and CompanyInventors: George R. Chapman, Jr., Donnan E. Priester
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Patent number: 5089200Abstract: Process of melt extruding through an extrusion die whose surface is coated with one or more metal oxides, M.sub.x O.sub.y, wherein M is a metal selected from the group consisting of Ti, Zr, Cr, Fe, Ni, Pd, Pt, Cu, Ag, Au, Al and Si, and x and y are selected to satisfy the valencies of M, a difficultly-melt-processible polymer containing 0.002-2 parts by weight, based on the weight of the polymer, of at least one melt-processible fluorocarbon polymer processing aid having a fluorine to carbon ratio of at least 1:2 and having metal oxide-reactive sites capable of reacting with or physically associating with the metal oxide of the die surface.Type: GrantFiled: September 20, 1990Date of Patent: February 18, 1992Assignee: E. I. DuPont de Nemours and CompanyInventors: George R. Chapman, Jr., Rita S. McMinn, Donnan E. Priester, William L. Phillips
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Patent number: 5057575Abstract: Polymer blend composition having improved processibility and comprising:(a) a major portion of a difficultly melt-procesible polymer, and(b) a minor portion of:1 at least an effective amount, to improve processibility, of a fluorocarbon copolymer which at the melt-processing temperature of (a) is either in a melted form if crystalline, or is above its glass transition temperature if amorphous, and(2) at least an effective amount, to improve processibility, of at least one tetrafluoroethylene homopolymer or copolymer of tetrafluoroethylene and at least one monomer copolymerizable therewith, wherein the mole ratio of fluorine to hydrogen is at least 1:1, and which is solid at the melt-processing temperature of (a);masterbatches comprised of the processing aid; and processes utilizing the processing aid.Type: GrantFiled: February 1, 1991Date of Patent: October 15, 1991Assignee: E. I. Du Pont de Nemours and CompanyInventors: George R. Chapman, Jr., Donnan E. Priester, Charles W. Stewart
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Patent number: 5013792Abstract: Polymer blend composition having improved processibility and comprising:(a) a major portion of a difficultly melt-processible polymer, and(b) a minor portion of:(1) at least an effective amount, to improve processibility, of a fluorocarbon copolymer which at the melt-processing temperature of (a) is either in a melted form if crystalline, or is above its glass transition temperature if amorphous, and(2) at least an effective amount, to improve processibility, of at least one tetrafluoroethylene homopolymer or copolymer of tetrafluoroethylene and at least one monomer copolymerizable therewith, wherein the mole ratio of fluorine to hydrogen is at least 1:1, and which is solid at the melt-processing temperature of (a);masterbatches comprised of the processing aid; and processes utilizing the processing aid.Type: GrantFiled: August 29, 1990Date of Patent: May 7, 1991Assignee: E. I. Du Pont de Nemours and CompanyInventors: George R. Chapman, Jr., Donnan E. Priester, Charles W. Stewart
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Patent number: 5010130Abstract: Improved polymer blend composition having improved processibility and comprising:(a) a major portion of a difficultly melt-processible polymer, and(b) a minor portion of:(1) at least an effective amount, to improve processibility, of a fluorocarbon copolymer which at the melt-processing temperature of (a) is either in a melted form if crystalline, or is above its glass transition temperature if amorphous, and(2) at least an effective amount, to improve processibility, of at least one tetrafluoroethylene homopolymer or copolymer of tetrafluoroethylene and at least one monomer copolymerizable therewith, wherein the mole ratio of fluorine to hydrogen is at least 1:1, and which is solid at the melt processing temperature of (a),said composition further characterized in that it contains an abrasive inorganic filler that retards the processibility of (a) in the presence of (b)(1) and (b)(2), the improvement consisting of minimizing the retarding effect of the inorganic filler by employing (b)(1) having an apparentType: GrantFiled: May 15, 1990Date of Patent: April 23, 1991Assignee: E. I. Du Pont de Nemours and CompanyInventors: George R. Chapman, Jr., Lee A. Gorthey, Donnan E. Priester
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Patent number: 4927773Abstract: A method of forming in a semiconductor material a region having a different chemical composition or a different concentration than a chemical composition or concentration of material surrounding the region. The method includes an initial step of providing a substantially single crystalline body of material, such as an epitaxial layer 10 of HgCdTe. Another step forms a cap layer 12 over a surface of the body, the layer having a thickness T. The cap layer 12 is comprised of a layer of polycrystalline material, such as CdTe, or is comprised of a layer of an organic material, an amorphous dielectric or a single-crystalline layer. A further step implants a selected chemical species through an upper surface of the cap, the species being implanted to a depth such that substantially no implant damage is sustained by the underlying body. In p-n junction formation the species is selected to form a region having an opposite type of electrical conductivity than the conductivity of the layer 10.Type: GrantFiled: June 5, 1989Date of Patent: May 22, 1990Assignee: Santa Barbara Research CenterInventors: Michael D. Jack, George R. Chapman, Michael Ray
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Patent number: 4904735Abstract: Polymer blend composition having improved processibility and comprising:(a) a major portion of a difficultly melt-processible polymer, and(b) a minor portion of:(1) at least an effective amount, to improve processibility, of a fluorocarbon copolymer which at the melt-processing temperature of (a) is either in a melted form if crystalline, or is above its glass transition temperature if amorphous, and(2) at least an effective amount, to improve processibility, of at least one tetrafluoroethylene homopolymer or copolymer of tetrafluoroethylene and at least one monomer copolymerizable therewith, wherein the mole ratio of fluorine to hydrogen is at least 1:1, and which is solid at the melt-processing temperature of (a);masterbatches comprised of the processing aid; and processes utilizing the processing aid.Type: GrantFiled: July 8, 1988Date of Patent: February 27, 1990Assignee: E. I. Du Pont de Nemours and CompanyInventors: George R. Chapman, Jr., Donnan E. Priester