Patents by Inventor David M. Hoffman

David M. Hoffman 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).

  • Patent number: 4764679
    Abstract: Quantum detection efficiency and spatial resolution in a kinestatic charge detector are improved by utilization of an x-ray transmissive device positioned within a collection volume of a kinestatic charge detector x-ray detection chamber for displacing the charge carrier generating medium within predetermined areas of the chamber. Within the chamber, quantum detection efficiency and spatial resolution are affected by distortion in electric field lines existing between a high voltage anode and a relatively low voltage collector electrode. The distorted field lines cause charge carriers generated in the medium by impinging radiation to impact on either the walls of the chamber or to follow non-linear paths between the point of creation and the collection electrode. By displacing the medium in the chamber in areas having the greatest electric field distortion, the quantum detection efficiency and spatial resolution are improved.
    Type: Grant
    Filed: August 12, 1986
    Date of Patent: August 16, 1988
    Assignee: General Electric Company
    Inventors: David L. McDaniel, Paul R. Granfors, David M. Hoffman
  • Patent number: 4686369
    Abstract: An apparatus for detecting propogating energy in a defined space includes a medium disposed within the space which interacts with the incident propogating energy to produce secondary energy. An electrostatic field is impressed across the defined space for directing the secondary energy toward a planar detector located at one end of the space. Adjacent the detector is positioned a planar grid for preventing the secondary energy from being detected by the detector prior to passage through the grid. The grid comprises a three layer device having a middle layer formed of an electrically insulative sheet material of a relatively stiff structure. The other two layers comprise conductive layers on opposed surfaces of the first layer which are connected to an electric potential for creating a field across the grid structure and a further field between the grid structure and the detector for accelerating the secondary energy toward the detector in the area of the grid at a space between the grid and detector.
    Type: Grant
    Filed: December 13, 1985
    Date of Patent: August 11, 1987
    Assignee: General Electric Company
    Inventors: David L. McDaniel, Paul R. Granfors, David M. Hoffman
  • Patent number: 4563584
    Abstract: A solid state detector in which each scintillator is optimally configured and coupled with its associated sensing diode in a way which exploits light piping effects to enhance efficiency. Preferably, the detector is modular in nature. Each scintillator is a crystal having an index of refraction which differs as a function of direction through the crystal lattice, with the lowest index of refraction being parallel to the cleavage plane. The sides of each scintillator bar conform with the cleavage plane and are highly polished to light pipe photons created in the scintillator to the rear face for collection by an associated photodiode. The rear face is roughened to de-trap light, allowing transfer from the scintillator to the diode. Optical coupling means join the scintillators to their associated diodes to further enhance light transfer.
    Type: Grant
    Filed: December 29, 1982
    Date of Patent: January 7, 1986
    Assignee: General Electric Company
    Inventors: David M. Hoffman, Jack D. Kingsley, Roger S. Ehle
  • Patent number: 4560877
    Abstract: A solid state detector in which each scintillator is optimally configured and coupled with its associated sensing diode in a way which exploits light piping effects to enhance efficiency, and at the same time provide a detector which is modular in nature. To achieve light piping, the scintillator crystal is oriented such that its sides conform with the crystal cleavage plane, and the sides are highly polished. An array of tungsten collimator plates define the individual channels. Multi-channel scintillator/diode modules are mounted behind and in registry with the plurality of collimator plates. A plurality of scintillators are bonded together after coating the surfaces thereof to minimize optical crosstalk. After lapping the face of the scintillator module, it is then bonded to a diode module with individual scintillators in registration with individual diodes. The module is then positioned in the detector array with collimator plates at the junctions between the scintillators.
    Type: Grant
    Filed: December 29, 1982
    Date of Patent: December 24, 1985
    Assignee: General Electric Company
    Inventor: David M. Hoffman
  • Patent number: 4517103
    Abstract: Lubricating compositions having improved extreme pressure properties are disclosed. The compositions comprise a lubricating grease or a lubricating oil dispersion and an effective amount of 5,5'-dithiobis(1,3,4-thiadiazole-2-thiol).
    Type: Grant
    Filed: April 18, 1983
    Date of Patent: May 14, 1985
    Assignee: R. T. Vanderbilt Company, Inc.
    Inventors: David M. Hoffman, John J. Feher, Homer H. Farmer
  • Patent number: 4491732
    Abstract: In a modular solid state detector of the type including a scintillator and diodes for converting x-ray flux to a measurable electrical signal, the diodes are mounted out of the path of incident x-radiation to minimize noise and to limit degradation. The resulting configuration reduces efficiency because the active diode area is limited and the length of the light path between the scintillator and diode is increased. In order to compensate for that reduction in efficiency, optical potting material is used to join the scintillator to the diodes in order to minimize light attenuation between those elements. In addition, the outer surface of the cured optical potting material is coated with a thin specular layer of silver to keep the light within the optical potting material and thus most efficiently reflected from the scintillator to the diode.
    Type: Grant
    Filed: August 25, 1982
    Date of Patent: January 1, 1985
    Assignee: General Electric Company
    Inventors: Dennis H. Pritzkow, Neil W. Loomis, Thomas M. Golner, David M. Hoffman
  • Patent number: 4417144
    Abstract: A modular solid-state detector cell which intimately associates a scintillator body with a pair of photoresponsive semiconductors so as to present on a single collimator plate all of the elements necessary for transforming incident X-radiation into a measurable electrical signal. The detector is provided with a precision slotted mounting arrangement for receiving the unit cells, and the cells when positioned within the detector assembly have the photoresponsive semiconductors enclosed within the light tight cell. The unit is adaptable to off-line testing of the separate cells for screening before assembly.
    Type: Grant
    Filed: February 23, 1981
    Date of Patent: November 22, 1983
    Assignee: General Electric Company
    Inventors: David M. Hoffman, Neil W. Loomis, Ralph C. Ehlert, Peter S. Shelley
  • Patent number: 4414473
    Abstract: A resilient locking and sealing arrangement for a multi-channel reflective cavity scintillation detector useful in a CT scanner. The absorption coefficient of the detector window is minimized in order to enhance detector efficiency, by forming such window of layers of woven graphite fiber bonded together with epoxy. The detector window includes resilient sealing means positioned to engage the leading edge of unit cell elements assembled to form a detector array. Resilient lock means force the plate into a reference position and into contact with the resilient sealing means thereby to accurately locate the plate in the array, and also to provide an effective light seal.
    Type: Grant
    Filed: February 23, 1981
    Date of Patent: November 8, 1983
    Assignee: General Electric Company
    Inventors: David M. Hoffman, Dennis Pritzkow, George R. Lang
  • Patent number: 4161655
    Abstract: An array of electrode plates are arranged in parallel and spaced apart relationship to define ionization cells in a channel within a housing that is occupied by high pressured gas. A broad beam of x-ray photons penetrates a window in the housing and produces ionization events that result in analog signals corresponding with photon energies and intensities. Conduction of the signals from the interior to the exterior of the detector housing is accomplished with a printed circuit board assembly that is sealed between the housing and its cover.
    Type: Grant
    Filed: November 28, 1977
    Date of Patent: July 17, 1979
    Assignee: General Electric Company
    Inventors: Dennis J. Cotic, David M. Hoffman, Peter S. Shelley, Laurel J. Zech