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).

  • Publication number: 20020161120
    Abstract: 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: Application
    Filed: September 17, 2001
    Publication date: October 31, 2002
    Inventors: George R. Chapman, Steven R. Oriani
  • Patent number: 5959339
    Abstract: 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: Grant
    Filed: March 19, 1996
    Date of Patent: September 28, 1999
    Assignee: Raytheon Company
    Inventors: George R. Chapman, Kenneth Kosai
  • Patent number: 5581084
    Abstract: 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: Grant
    Filed: June 7, 1995
    Date of Patent: December 3, 1996
    Assignee: Santa Barbara Research Center
    Inventors: George R. Chapman, Bonnie A. Baumgratz, Michael Ray
  • Patent number: 5547761
    Abstract: 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: Grant
    Filed: June 1, 1995
    Date of Patent: August 20, 1996
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: George R. Chapman, Jr., Richard A. Morgan, Charles W. Stewart, William H. Tuminello, John G. Van Alsten, Randall A. Vogel, Mark E. Wagman
  • Patent number: 5464904
    Abstract: 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: Grant
    Filed: November 16, 1994
    Date of Patent: November 7, 1995
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: George R. Chapman, Jr., Lewis E. Crenshaw, Rita S. McMinn, Richard A. Morgan, Donnan E. Priester, Charles W. Stewart, Robert E. Tarney
  • Patent number: 5457331
    Abstract: 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: Grant
    Filed: April 8, 1993
    Date of Patent: October 10, 1995
    Assignee: Santa Barbara Research Center
    Inventors: Kenneth Kosai, George R. Chapman
  • Patent number: 5266639
    Abstract: 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: Grant
    Filed: August 28, 1992
    Date of Patent: November 30, 1993
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: 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
  • Patent number: 5132368
    Abstract: 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: Grant
    Filed: September 3, 1991
    Date of Patent: July 21, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: George R. Chapman, Jr., Donnan E. Priester, Charles W. Stewart, Robert E. Tarney
  • Patent number: 5106911
    Abstract: 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: Grant
    Filed: July 15, 1991
    Date of Patent: April 21, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: George R. Chapman, Jr., Donnan E. Priester
  • Patent number: 5089200
    Abstract: 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: Grant
    Filed: September 20, 1990
    Date of Patent: February 18, 1992
    Assignee: E. I. DuPont de Nemours and Company
    Inventors: George R. Chapman, Jr., Rita S. McMinn, Donnan E. Priester, William L. Phillips
  • Patent number: 5057575
    Abstract: 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: Grant
    Filed: February 1, 1991
    Date of Patent: October 15, 1991
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: George R. Chapman, Jr., Donnan E. Priester, Charles W. Stewart
  • Patent number: 5013792
    Abstract: 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: Grant
    Filed: August 29, 1990
    Date of Patent: May 7, 1991
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: George R. Chapman, Jr., Donnan E. Priester, Charles W. Stewart
  • Patent number: 5010130
    Abstract: 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 apparent
    Type: Grant
    Filed: May 15, 1990
    Date of Patent: April 23, 1991
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: George R. Chapman, Jr., Lee A. Gorthey, Donnan E. Priester
  • Patent number: 4927773
    Abstract: 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: Grant
    Filed: June 5, 1989
    Date of Patent: May 22, 1990
    Assignee: Santa Barbara Research Center
    Inventors: Michael D. Jack, George R. Chapman, Michael Ray
  • Patent number: 4904735
    Abstract: 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: Grant
    Filed: July 8, 1988
    Date of Patent: February 27, 1990
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: George R. Chapman, Jr., Donnan E. Priester