Patents by Inventor David A. Cammack

David A. Cammack 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: 6653799
    Abstract: A gas discharge lamp is driven by a bridge circuit which produces a pulse voltage signal. The bridge circuit is pulse width modulated at an operational frequency, and has a power input for receiving power from a power source, and a control signal input for receiving a control signal that effects sweeping of the operational frequency and generation of the pulse voltage signal. The system further includes a controller for controlling the bridge circuit, the controller comprising circuitry for (i) generating a signal comprising a frequency swept signal that is amplitude modulated by a fixed frequency signal, the highest frequency of the frequency swept signal being lower than the operational frequency, and the signal generated by the controller being inputted into the control signal input of the bridge circuit, and (ii) periodically sweeping the operational frequency of the bridge circuit. The system further includes a filter circuit for filtering the pulse voltage signal.
    Type: Grant
    Filed: July 30, 2001
    Date of Patent: November 25, 2003
    Assignee: Koninklijke Philips Electronics N.V.
    Inventor: David A. Cammack
  • Patent number: 6489731
    Abstract: A power supply and/or ballast optimizes performance of an electrical load, such as a High Intensity Discharge (HID) lamp by monitoring the current and voltage signal driving the load, and calculating a representative portion of the power spectrum being delivered to the load. The calculated portion of the delivered power spectrum is compared to a desired power spectrum, and the input signal to the load is modified in such a manner that the delivered power spectrum will more closely match the desired power spectrum. The input current and voltage, and the frequency at the load are thus not controlled directly, but are an indirect result of applying the modified input power spectrum to the load. By utilizing the input power spectrum in this manner, a power supply and/or ballast provides improved control and performance when used with electrical loads such as HID lamps.
    Type: Grant
    Filed: July 27, 2001
    Date of Patent: December 3, 2002
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Gert W. Bruning, David A. Cammack
  • Publication number: 20020041165
    Abstract: A system and method for driving a gas discharge lamp. In one embodiment, the system comprises a bridge circuit for generating a pulse voltage signal wherein the bridge circuit has an operational frequency, a power input for receiving power from a power source, and a control signal input for receiving a control signal that effects sweeping of the operational frequency and generation of the pulse voltage signal. The system further includes a controller for controlling the bridge circuit, the controller comprising circuitry for (i) generating a signal comprising a frequency swept signal that is amplitude modulated by a fixed frequency signal wherein the signal generated by the controller is inputted into the control signal input of the bridge circuit, and (ii) periodically sweeping the operational frequency of the bridge circuit. The system further includes a filter circuit for filtering the pulse voltage signal.
    Type: Application
    Filed: July 30, 2001
    Publication date: April 11, 2002
    Applicant: Koninklijke Philips Electronics N.V
    Inventor: David A. Cammack
  • Patent number: 5965976
    Abstract: A high pressure gas discharge lamp and the method of making same utilizing integrated circuit fabrication techniques. The lamp is manufactured from heat and pressure resistant planar substrates in which cavities are etched, by integrated circuit manufacturing techniques, so as to provide a cavity forming the gas discharge tube. Electrodes are deposited in the cavity. The cavity is filled with gas discharge materials such as mercury vapor, sodium vapor or metal halide. The substrates are bonded together and channels may be etched in the substrate so as to provide a means for connection to the electrodes. Lamps having ignition enhancing and hot restrike features, as well as single-sided electrodes, are disclosed.
    Type: Grant
    Filed: December 19, 1997
    Date of Patent: October 12, 1999
    Assignee: Philips Electronics North America Corp.
    Inventors: Babar Ali Khan, David A. Cammack, Ronald D. Pinker, Jerry Kramer, Vivek Mehrotra
  • Patent number: 5955838
    Abstract: A high pressure gas discharge lamp and the method of making same utilizing integrated circuit fabrication techniques. The lamp is manufactured from heat and pressure resistant planar substrates in which cavities are etched, by integrated circuit manufacturing techniques, so as to provide a cavity forming the gas discharge tube. Electrodes are deposited in the cavity. The cavity is filled with gas discharge materials such as mercury vapor, sodium vapor or metal halide. The substrates are bonded together and channels may be etched in the substrate so as to provide a means for connection to the electrodes. Electrodeless RF activated lamps may also be fabricated by this technique. Lamps fabricated from three or more planar substrates are disclosed.
    Type: Grant
    Filed: May 15, 1997
    Date of Patent: September 21, 1999
    Assignee: Philips Electronics North America Corp.
    Inventors: Babar Ali Khan, David A. Cammack, Ronald D. Pinker
  • Patent number: 5919070
    Abstract: A vacuum state microelectronic device comprising at least a cathode, an anode, and a grid, disposed in a cavity, and formed by the wafer bonding of two planar substrates. The technology permits multiple vacuum state microelectronic devices (vacuum tubes) to be arrayed on a single substrate in an integrated manner.
    Type: Grant
    Filed: August 16, 1996
    Date of Patent: July 6, 1999
    Assignee: Philips Electronics North America Corporation
    Inventors: Babar A. Khan, David A. Cammack, Ronald Pinker
  • Patent number: 5808410
    Abstract: A liquid crystal display is provided using a flat panel of microlamps being formed from gas discharge display structures and made by the method of making the same utilizing integrated circuit fabrication techniques. The flat panel of microlamps is formed into an array for providing light to individual pixels, or a small number of pixels, in a liquid crystal display. Such microlamp lighting can increase the illumination of LCDs.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: September 15, 1998
    Assignee: Philips Electronics North America Corporation
    Inventors: Ronald D. Pinker, Peter J. Janssen, Babar A. Khan, David A. Cammack
  • Patent number: 5624293
    Abstract: A high pressure gas discharge lamp and the method of making same utilizing integrated circuit fabrication techniques. The lamp is manufactured from heat and pressure resistant planar substrates in which cavities are etched, by integrated circuit manufacturing techniques, so as to provide a cavity forming the gas discharge tube. Electrodes are deposited in the cavity. The cavity is filled with gas discharge materials such as mercury vapor, sodium vapor or metal halide. The substrates are bonded together and channels may be etched in the substrate so as to provide a means for connection to the electrodes. Electrodeless RF activated lamps may also be fabricated by this technique. Micro-lasers may also be fabricated by this technique as well.
    Type: Grant
    Filed: June 6, 1995
    Date of Patent: April 29, 1997
    Assignee: Philips Electronics North America Corporation
    Inventors: Babar A. Khan, David A. Cammack, Ronald D. Pinker, Nikhil R. Taskar
  • Patent number: 5598052
    Abstract: A vacuum state microelectronic device comprising at least a cathode, an anode, and a grid, disposed in a cavity, and formed by the wafer bonding of two planar substrates. The technology permits multiple vacuum state microelectronic devices (vacuum tubes) to be arrayed on a single substrate in an integrated manner. So as to form a bond as strong as the substrate itself.
    Type: Grant
    Filed: December 16, 1994
    Date of Patent: January 28, 1997
    Assignee: Philips Electronics North America
    Inventors: Babar A. Khan, David A. Cammack, Ronald Pinker
  • Patent number: 5574327
    Abstract: A microlamp structure and method of making the same is set forth having light collection and light directing features. The microlamp structure is of a luminescent gas discharge type. The light collection structures may include types of reflectors while the light directing structures may include lens features. These features may be included singly or in combination and may be provided on the exterior of the microlamp structure or on the interior of the microlamp at a light forming cavity.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: November 12, 1996
    Assignee: Philips Electronics North America
    Inventors: David A. Cammack, Ronald D. Pinker, Babar A. Khan
  • Patent number: 5438343
    Abstract: A gas discharge display and the method of making same utilizing integrated circuit fabrication techniques. The display is manufactured from heat and pressure resistant planar substrates in which cavities are etched, by integrated circuit manufacturing techniques, so as to provide individual pixels. Orthogonal electrodes are deposited on the substrates and extend into the cavities. The cavities are filled with gas discharge materials, such as plasma, upon energization of the electrodes the individual cavities forming the pixels may be individually activated.
    Type: Grant
    Filed: December 30, 1993
    Date of Patent: August 1, 1995
    Assignee: Philips Electronics North America Corporation
    Inventors: Babar A. Khan, David A. Cammack, Ronald D. Pinker, Jerry M. Kramer
  • Patent number: 4905076
    Abstract: A three dimensional projection television system in which the screen of the receiver alternatively receives a television picture field as polarized by polarizing apparatus and a television picture field which is orthogonally polarized with respect to the fields polarized by the polarizing apparatus. Also disclosed in a receiver for use in such a system. The receiver includes three projectors each projecting through a polarizer and an individual electro-optical crystal device.
    Type: Grant
    Filed: August 12, 1986
    Date of Patent: February 27, 1990
    Assignee: N.A. Philips & U.S. Philips Corporation
    Inventors: Marcellinus J. J. C. Annegarn, Sing L. Tan, David A. Cammack, Douglas A. Stanton, Rameshwar N. Bharagava