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).
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Patent number: 6653799Abstract: 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: GrantFiled: July 30, 2001Date of Patent: November 25, 2003Assignee: Koninklijke Philips Electronics N.V.Inventor: David A. Cammack
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Patent number: 6489731Abstract: 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: GrantFiled: July 27, 2001Date of Patent: December 3, 2002Assignee: Koninklijke Philips Electronics N.V.Inventors: Gert W. Bruning, David A. Cammack
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Publication number: 20020041165Abstract: 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: ApplicationFiled: July 30, 2001Publication date: April 11, 2002Applicant: Koninklijke Philips Electronics N.VInventor: David A. Cammack
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Patent number: 5965976Abstract: 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: GrantFiled: December 19, 1997Date of Patent: October 12, 1999Assignee: Philips Electronics North America Corp.Inventors: Babar Ali Khan, David A. Cammack, Ronald D. Pinker, Jerry Kramer, Vivek Mehrotra
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Patent number: 5955838Abstract: 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: GrantFiled: May 15, 1997Date of Patent: September 21, 1999Assignee: Philips Electronics North America Corp.Inventors: Babar Ali Khan, David A. Cammack, Ronald D. Pinker
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Patent number: 5919070Abstract: 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: GrantFiled: August 16, 1996Date of Patent: July 6, 1999Assignee: Philips Electronics North America CorporationInventors: Babar A. Khan, David A. Cammack, Ronald Pinker
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Patent number: 5808410Abstract: 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: GrantFiled: June 7, 1995Date of Patent: September 15, 1998Assignee: Philips Electronics North America CorporationInventors: Ronald D. Pinker, Peter J. Janssen, Babar A. Khan, David A. Cammack
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Patent number: 5624293Abstract: 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: GrantFiled: June 6, 1995Date of Patent: April 29, 1997Assignee: Philips Electronics North America CorporationInventors: Babar A. Khan, David A. Cammack, Ronald D. Pinker, Nikhil R. Taskar
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Patent number: 5598052Abstract: 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: GrantFiled: December 16, 1994Date of Patent: January 28, 1997Assignee: Philips Electronics North AmericaInventors: Babar A. Khan, David A. Cammack, Ronald Pinker
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Patent number: 5574327Abstract: 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: GrantFiled: June 7, 1995Date of Patent: November 12, 1996Assignee: Philips Electronics North AmericaInventors: David A. Cammack, Ronald D. Pinker, Babar A. Khan
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Patent number: 5438343Abstract: 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: GrantFiled: December 30, 1993Date of Patent: August 1, 1995Assignee: Philips Electronics North America CorporationInventors: Babar A. Khan, David A. Cammack, Ronald D. Pinker, Jerry M. Kramer
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Patent number: 4905076Abstract: 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: GrantFiled: August 12, 1986Date of Patent: February 27, 1990Assignee: N.A. Philips & U.S. Philips CorporationInventors: Marcellinus J. J. C. Annegarn, Sing L. Tan, David A. Cammack, Douglas A. Stanton, Rameshwar N. Bharagava