Patents by Inventor John K. Roberts

John K. Roberts 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: 8278846
    Abstract: Methods of calibrating a lighting panel including a plurality of segments, each of said segments configured to emit a first color light and a second color light in response to pulse width modulation control signals having respective duty cycles include determining an average segment luminance for the lighting panel, determining a luminance variation of each segment to the average segment luminance, comparing the luminance variation of each segment to a threshold, and adjusting the duty cycle of at least one color of at least one segment to reduce the luminance variation in response to the luminance variation of a segment exceeding the threshold. Calibration systems are also disclosed.
    Type: Grant
    Filed: November 17, 2006
    Date of Patent: October 2, 2012
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Keith J. Vadas, Chenhua You
  • Publication number: 20120235575
    Abstract: A lighting system includes a lighting panel having a string of solid state lighting devices and a current supply circuit having a voltage input terminal, a control input terminal, and first and second output terminals coupled to the string of solid state lighting devices. The current supply circuit is configured to supply an on-state drive current to the string of solid state lighting devices in response to a control signal. The current supply circuit includes a charging inductor coupled to the voltage input terminal and an output capacitor coupled to the first output terminal. The current supply circuit is configured to operate in continuous conduction mode in which current continuously flows through the charging inductor while the on-state drive current is supplied to the string of solid state light emitting devices.
    Type: Application
    Filed: May 11, 2012
    Publication date: September 20, 2012
    Inventors: John K. Roberts, Keith J. Vadas, Muhinthan Murugesu
  • Patent number: 8203286
    Abstract: A lighting panel system includes a lighting panel having a string of solid state lighting devices and a current supply circuit having a voltage input terminal, a control input terminal, and first and second output terminals coupled to the string of solid state lighting devices. The current supply circuit is configured to supply an on-state drive current to the string of solid state lighting devices in response to a control signal. The current supply circuit includes a charging inductor coupled to the voltage input terminal and an output capacitor coupled to the first output terminal. The current supply circuit is configured to operate in continuous conduction mode in which current continuously flows through the charging inductor while the on-state drive current is supplied to the string of solid state light emitting devices.
    Type: Grant
    Filed: December 23, 2010
    Date of Patent: June 19, 2012
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Keith J. Vadas, Muhinthan Murugesu
  • Publication number: 20120025723
    Abstract: Provided are systems and methods for controlling a solid state lighting panel. A system according to some embodiments of the invention includes a controller that provides control signals to current drivers that are configured to provide current to multiple solid state lighting devices. The system also includes a sequence generator that generates a firing sequence for firing multiple strings of slid state lighting devices.
    Type: Application
    Filed: October 11, 2011
    Publication date: February 2, 2012
    Inventors: John K. Roberts, Keith J. Vadas
  • Patent number: 8049709
    Abstract: Provided are systems and methods for controlling a solid state lighting panel. A system according to some embodiments of the invention includes a controller that provides control signals to current drivers that are configured to provide current to multiple solid state lighting devices. The system also includes a sequence generator that generates a firing sequence for firing multiple strings of slid state lighting devices.
    Type: Grant
    Filed: May 8, 2007
    Date of Patent: November 1, 2011
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Keith J. Vadas
  • Publication number: 20110228530
    Abstract: A solid state lighting unit includes a plurality of solid state lighting tiles including a planar surface and a plurality of solid state light sources on the planar surface. The lighting unit includes a plurality of bar support members. Respective ones of the bar support members include at least two of the plurality of tiles affixed thereon to form respective bar assemblies, and respective ones of the solid state light sources on the solid state lighting tiles of a bar assembly are electrically connected in series so as to be simultaneously energized upon application of a voltage thereto. Methods of forming a solid state lighting unit are also disclosed.
    Type: Application
    Filed: May 31, 2011
    Publication date: September 22, 2011
    Inventors: John K. Roberts, Paul E. Sims, Chenhua You
  • Patent number: 7993021
    Abstract: A solid state lighting tile includes a substrate and a plurality of lighting element clusters on a surface of the substrate. Respective ones of the plurality of lighting element clusters include first and second mounting positions configured to receive solid state light emitting devices, and at least first and second ones of the solid state lighting element clusters may be electrically connected in series. The tile further includes a plurality of solid state light emitting devices configured to emit a first color light, and respective ones of the solid state light emitting devices may be mounted in respective ones of the plurality of solid state lighting element clusters. One of the first color light emitting devices is mounted in the first mounting position of the first solid state lighting element cluster and a second of the first color light emitting devices is mounted in the second mounting position of the second solid state lighting element cluster.
    Type: Grant
    Filed: November 17, 2006
    Date of Patent: August 9, 2011
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Paul E. Sims, Chenhua You
  • Patent number: 7959325
    Abstract: A solid state lighting unit includes a plurality of solid state lighting tiles including a planar surface and a plurality of solid state light sources on the planar surface. The lighting unit includes a plurality of bar support members. Respective ones of the bar support members include at least two of the plurality of tiles affixed thereon to form respective bar assemblies, and respective ones of the solid state light sources on the solid state lighting tiles of a bar assembly are electrically connected in series so as to be simultaneously energized upon application of a voltage thereto. Methods of forming a solid state lighting unit are also disclosed.
    Type: Grant
    Filed: November 17, 2006
    Date of Patent: June 14, 2011
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Paul E. Sims, Chenhua You
  • Publication number: 20110127917
    Abstract: A lighting panel system includes a lighting panel having a string of solid state lighting devices and a current supply circuit having a voltage input terminal, a control input terminal, and first and second output terminals coupled to the string of solid state lighting devices. The current supply circuit is configured to supply an on-state drive current to the string of solid state lighting devices in response to a control signal. The current supply circuit includes a charging inductor coupled to the voltage input terminal and an output capacitor coupled to the first output terminal. The current supply circuit is configured to operate in continuous conduction mode in which current continuously flows through the charging inductor while the on-state drive current is supplied to the string of solid state light emitting devices.
    Type: Application
    Filed: December 23, 2010
    Publication date: June 2, 2011
    Inventors: John K. Roberts, Keith J. Vadas, Muhinthan Murugesu
  • Patent number: 7926300
    Abstract: A lighting panel system includes a lighting panel including a first string of solid state lighting devices configured to emit light at a first wavelength and a second string of solid state lighting devices configured to emit light at a second wavelength, different from the first wavelength, and a current supply circuit configured to supply a drive current to the first string in response to a control signal. A photosensor is arranged to receive light emitted by the panel, and a control system is configured to sample an output signal of the photosensor and adjust the control signal responsive thereto to thereby adjust an average current supplied to the first string by the current supply circuit. Methods of operating a lighting panel are also provided.
    Type: Grant
    Filed: March 6, 2006
    Date of Patent: April 19, 2011
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Keith J. Vadas, Chenhua You
  • Patent number: 7872430
    Abstract: A lighting panel system includes a lighting panel having a string of solid state lighting devices and a current supply circuit having a voltage input terminal, a control input terminal, and first and second output terminals coupled to the string of solid state lighting devices. The current supply circuit is configured to supply an on-state drive current to the string of solid state lighting devices in response to a control signal. The current supply circuit includes a charging inductor coupled to the voltage input terminal and an output capacitor coupled to the first output terminal. The current supply circuit is configured to operate in continuous conduction mode in which current continuously flows through the charging inductor while the on-state drive current is supplied to the string of solid state light emitting devices.
    Type: Grant
    Filed: November 17, 2006
    Date of Patent: January 18, 2011
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Keith J. Vadas, Muhinthan Murugesu
  • Publication number: 20100294913
    Abstract: A lighting panel includes a tile having a first side parallel to a principal plane of the lighting panel, a plurality of solid state lighting devices arranged on the first side of the tile and configured to emit light, a reflector sheet on the first side of the tile, and a brightness enhancement film on the reflector sheet. The reflector sheet may be arranged between the tile and the brightness enhancement film and the brightness enhancement film may be configured to increase the on-axis intensity of emitted light. A luminaire adapted for general illumination includes a lighting panel as described above, a current supply circuit configured to supply an on-state drive current to a string of lighting devices in response to a control signal, a photosensor arranged to receive light from one of the solid state lighting devices, and a control system configured to receive an output signal from the photosensor and to adjust the control signal responsive to the output signal of the photosensor.
    Type: Application
    Filed: August 5, 2010
    Publication date: November 25, 2010
    Inventor: John K. Roberts
  • Patent number: 7825600
    Abstract: A system and method of automatically controlling exterior vehicle lights includes an image sensor and a controller to generate control signals. The control signals are derived based on information obtained from the image sensor as well as other detected parameters pertaining to the detected light source(s), the vehicle having the inventive control system, and the ambient environment. The control circuit may simply turn certain exterior lights on or off, or change the brightness, aim, focus, etc. to produce various beam patterns that maximize the illuminated area in front of the vehicle without causing excessive glare in the eyes of other drivers.
    Type: Grant
    Filed: October 29, 2007
    Date of Patent: November 2, 2010
    Assignee: Gentex Corporation
    Inventors: Joseph S. Stam, Jon H. Bechtel, Spencer D. Reese, John K. Roberts, William L. Tonar, G. Bruce Poe, Douglas J. Newhouse
  • Publication number: 20100237806
    Abstract: Methods of controlling a backlight unit including a plurality of solid state light emitting devices include receiving a request to set a color point of the backlight unit at a requested color point, and determining if the requested color point is within an acceptable range. In response to the requested color point being outside the acceptable range, a modified color point is selected in response to the requested color point, and a color point of the backlight unit is set at the modified color point. Corresponding solid state lighting units are also disclosed.
    Type: Application
    Filed: March 25, 2010
    Publication date: September 23, 2010
    Inventors: John K. Roberts, Keith J. Vadas
  • Patent number: 7789529
    Abstract: An LED light unit includes a tile, a plurality of discrete LED light sources, and an edge connector. The LED light sources are on and dispersed across a major surface of the tile and are electrically connected to electrical pads along an edge region of the tile. The edge connector includes a plurality of contacts that are connected to a plurality of wires extending away from the edge connector, and is configured to releasably connect to an edge of the tile so that the contacts directly connect to the pads and electrically connect the wires of the edge connector to the LED light sources. An LED lighting assembly includes a plurality of the discrete tiles mounted to a plurality of bars, and a plurality of edge connectors that are each connected to an end one of the tiles along different ones of the bars.
    Type: Grant
    Filed: October 20, 2009
    Date of Patent: September 7, 2010
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Paul E. Sims
  • Patent number: 7777166
    Abstract: A lighting panel includes a tile having a first side parallel to a principal plane of the lighting panel, a plurality of solid state lighting devices arranged on the first side of the tile and configured to emit light, a reflector sheet on the first side of the tile, and a brightness enhancement film on the reflector sheet. The reflector sheet may be arranged between the tile and the brightness enhancement film and the brightness enhancement film may be configured to increase the on-axis intensity of emitted light. A luminaire adapted for general illumination includes a lighting panel as described above, a current supply circuit configured to supply an on-state drive current to a string of lighting devices in response to a control signal, a photosensor arranged to receive light from one of the solid state lighting devices, and a control system configured to receive an output signal from the photosensor and to adjust the control signal responsive to the output signal of the photosensor.
    Type: Grant
    Filed: April 21, 2006
    Date of Patent: August 17, 2010
    Assignee: Cree, Inc.
    Inventor: John K. Roberts
  • Patent number: 7772966
    Abstract: A vehicle communication and control system is provided that may be more readily installed in a vehicle and that utilizes minimal additional wiring. According to some of the disclosed embodiments, the electrical components of the “brick” of a communication and control system are integrated into a rearview mirror assembly. Preferably, the microwave antenna for the GPS and the cellular telephone antenna are also integrated into the rearview mirror assembly. Various functions and features of the system are also disclosed.
    Type: Grant
    Filed: January 3, 2008
    Date of Patent: August 10, 2010
    Assignee: Gentex Corporation
    Inventors: Robert R. Turnbull, Robert C. Knapp, Eric J. Walstra, Alan R. Watson, G. Bruce Poe, John K. Roberts, Wayne J. Rumsey
  • Patent number: 7712917
    Abstract: Methods of controlling a backlight unit including a plurality of solid state light emitting devices include receiving a request to set a color point of the backlight unit at a requested color point, and determining if the requested color point is within an acceptable range. In response to the requested color point being outside the acceptable range, a modified color point is selected in response to the requested color point, and a color point of the backlight unit is set at the modified color point. Corresponding solid state lighting units are also disclosed.
    Type: Grant
    Filed: May 21, 2007
    Date of Patent: May 11, 2010
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Keith J. Vadas
  • Patent number: 7690812
    Abstract: Provided are solid state lighting devices and methods for forming the same. A solid state lighting tile according to some embodiments of the invention includes a substrate, a solid state lighting element mounted on a surface of the substrate, and a reflector sheet on the surface of the substrate. A method of forming a solid state lighting device according to some embodiments of the invention includes providing a substrate of a solid state lighting tile, mounting a solid state lighting element on a surface of the substrate, and attaching a reflector sheet to the surface of the substrate.
    Type: Grant
    Filed: March 16, 2007
    Date of Patent: April 6, 2010
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Chenhua You, Paul E. Sims
  • Publication number: 20100039806
    Abstract: An LED light unit includes a tile, a plurality of discrete LED light sources, and an edge connector. The LED light sources are on and dispersed across a major surface of the tile and are electrically connected to electrical pads along an edge region of the tile. The edge connector includes a plurality of contacts that are connected to a plurality of wires extending away from the edge connector, and is configured to releasably connect to an edge of the tile so that the contacts directly connect to the pads and electrically connect the wires of the edge connector to the LED light sources. An LED lighting assembly includes a plurality of the discrete tiles mounted to a plurality of bars, and a plurality of edge connectors that are each connected to an end one of the tiles along different ones of the bars.
    Type: Application
    Filed: October 20, 2009
    Publication date: February 18, 2010
    Inventors: John K. Roberts, Paul E. Sims