Patents by Inventor Earl F. Crandall

Earl F. Crandall 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: 7514878
    Abstract: A high frequency sinusoidal wave is generated and applied directly to a gas discharge lamp in a power efficient electronic ballast. Uniting a high frequency current fed oscillator with a transformer, where direct current may be applied to the center tap of the transformer primary winding to enable the impression of a sinusoidal alternating current at the secondary winding. This sinusoidal alternating current is applied directly to a gas discharge lamp. Feedback from the transformer controls the switching of the oscillator at resonant frequency.
    Type: Grant
    Filed: April 2, 2004
    Date of Patent: April 7, 2009
    Assignee: PureSpectrum, Inc.
    Inventors: Earl F. Crandall, Robert C. Smallwood, Sr.
  • Patent number: 7514879
    Abstract: A gas discharge lamp is driven with a constant current square wave from a current transformer where the number of volt-microseconds are designed such that at the start of each square wave, the voltage rises to the required ionization potential for the lamp, while the plasma has not yet started to conduct. As soon as the lamp ionizes the gas within the lamp and current flows, the voltage drops and current flows at the desired level. The current level is set to prevent the input of excessive power pulses into the lamp, to reduce the creation of infrared photons. In addition, the plasma is driven at this current level almost continuously (with reversing polarity), which does not allow the plasma time to cool down. Consequently, the lamp becomes a more efficient light emitter, thereby requiring less energy to achieve the same light output.
    Type: Grant
    Filed: November 24, 2004
    Date of Patent: April 7, 2009
    Assignee: PureSpectrum, Inc.
    Inventors: Earl F. Crandall, Robert C. Smallwood, Ray King
  • Patent number: 7388334
    Abstract: A high frequency sinusoidal wave is generated and applied directly to a gas discharge lamp in multiple phases in a power efficient electronic ballast. Uniting a high frequency current fed oscillator with a transformer, where direct current may be applied to the center tap of the transformer primary winding through an appropriately sized inductor to enable the impression of a sinusoidal alternating current at the secondary winding. This sinusoidal alternating current is applied directly to a gas discharge lamp. Feedback from the transformer controls the switching of the oscillator at resonant frequency.
    Type: Grant
    Filed: April 2, 2004
    Date of Patent: June 17, 2008
    Assignee: PureSpectrum, Inc.
    Inventors: Earl F. Crandall, Robert C. Smallwood, Sr., Robert G. Crandall
  • Patent number: 7252406
    Abstract: A gas discharge lamp includes a plurality of gas discharge bulbs arranged on a base along a perimeter defining a middle region and at least one reflective mirror positioned in the middle region and operative to reflect light outward from the middle region. Alternatively, at least one light pipe can be positioned in the middle region and configured to gather light and redirect the light outward from the middle region.
    Type: Grant
    Filed: April 2, 2004
    Date of Patent: August 7, 2007
    Assignee: Purespectrum LLC
    Inventor: Earl F. Crandall
  • Patent number: 7235932
    Abstract: An electronic ballast for a gas discharge lamp includes an adjustable constant current source circuit adapted to convert a direct current input to provide an initial start current and a variably controlled constant current. A coupling transformer circuit is connected to the adjustable constant current source and adapted to couple the initial start current to the gas discharge lamp to provide a corresponding start voltage approximately equal to a strike voltage of the gas discharge lamp and to convert the variably controlled constant current to a square wave current to power the gas discharge lamp thereafter. A current sense circuit is adapted to sense an operating current at the coupling transformer and to provide corresponding current sense information to the adjustable constant current source, wherein said current sense information is used to vary the variably controlled constant current.
    Type: Grant
    Filed: July 30, 2004
    Date of Patent: June 26, 2007
    Assignee: PureSpectrum, Inc.
    Inventors: Earl F. Crandall, Ray King
  • Patent number: 6975069
    Abstract: A multi-phase gas discharge lamp includes an interior space defined by at least one wall. A plasma-forming gas is disposed in the interior space. At least three electrodes are positioned to access the interior space, each electrode adapted to receive one phase of a multi-phase AC power source and energize the plasma-forming gas in response. The multi-phase energization of a plasma-forming gas maintains the energy level in the plasma, which maximizes efficiency of a gas discharge lamp.
    Type: Grant
    Filed: April 2, 2004
    Date of Patent: December 13, 2005
    Assignee: Transworld Lighting, Inc.
    Inventor: Earl F. Crandall
  • Publication number: 20040195974
    Abstract: A gas discharge lamp includes a plurality of gas discharge bulbs arranged on a base along a perimeter defining a middle region and at least one reflective mirror positioned in the middle region and operative to reflect light outward from the middle region. Alternatively, at least one light pipe can be positioned in the middle region and configured to gather light and redirect the light outward from the middle region.
    Type: Application
    Filed: April 2, 2004
    Publication date: October 7, 2004
    Inventor: Earl F. Crandall
  • Publication number: 20040195953
    Abstract: A multi-phase gas discharge lamp includes an interior space defined by at least one wall. A plasma-forming gas is disposed in the interior space. At least three electrodes are positioned to access the interior space, each electrode adapted to receive one phase of a multi-phase AC power source and energize the plasma-forming gas in response. The multi-phase energization of a plasma-forming gas maintains the energy level in the plasma, which maximizes efficiency of a gas discharge lamp.
    Type: Application
    Filed: April 2, 2004
    Publication date: October 7, 2004
    Applicant: Transworld Lighting, Inc.
    Inventor: Earl F. Crandall
  • Patent number: 4808773
    Abstract: A cable for use in ultra-low impedance electrical interconnections and a connector for optional use therewith. A two-conductor version of the cable is formed, for example, by the steps of, disposing an elongated first strip of electrical conductor on an elongated first strip of electrical insulator; disposing an elongated second strip of electrical insulator on the first strip of electrical conductor; disposing an elongated second strip of electrical conductor on the second strip of electrical insulator; and, winding the strips in combination from one side to the other to form the cable as a spiral in cross section. The electrical conductors can comprise elongated rectangular sheets of metal foil or, alternatively to provide a cable of increased flexibility, a plurality of wires disposed side-by-side along the length of the associated strip of electrical insulator.
    Type: Grant
    Filed: October 1, 1987
    Date of Patent: February 28, 1989
    Assignee: Digital Equipment Corporation
    Inventor: Earl F. Crandall