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: 9605835
    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: February 2, 2015
    Date of Patent: March 28, 2017
    Assignee: Cree, Inc.
    Inventor: John K. Roberts
  • Publication number: 20160010830
    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: February 2, 2015
    Publication date: January 14, 2016
    Inventor: John K. Roberts
  • Patent number: 8946609
    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: October 22, 2012
    Date of Patent: February 3, 2015
    Assignee: Cree, Inc.
    Inventor: John K. Roberts
  • Patent number: 8941331
    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: Grant
    Filed: May 17, 2013
    Date of Patent: January 27, 2015
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Keith J. Vadas, Muhinthan Murugesu
  • Publication number: 20140361712
    Abstract: Provided are systems and methods for providing a stabilized color management system in a solid state lighting panel. Methods according to some embodiments include receiving, in the microcontroller, a color management reference value corresponding to a color characteristic of the solid state lighting panel and adjusting a control mode of the microcontroller responsive to the color management reference value.
    Type: Application
    Filed: August 21, 2014
    Publication date: December 11, 2014
    Inventors: John K. Roberts, Keith J. Vadas
  • Patent number: 8829820
    Abstract: Provided are systems and methods for protecting display components from adverse operating conditions. A lighting panel system according to some embodiments includes a lighting panel including a plurality of strings of solid state lighting devices arranged across the panel and a protection system configured to determine an adverse operating condition and adjust a lighting panel luminance setting responsive to the adverse operating condition.
    Type: Grant
    Filed: August 10, 2007
    Date of Patent: September 9, 2014
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Keith J. Vadas
  • Patent number: 8823630
    Abstract: Provided are systems and methods for providing a stabilized color management system in a solid state lighting panel. Methods according to some embodiments include receiving, in the microcontroller, a color management reference value corresponding to a color characteristic of the solid state lighting panel and adjusting a control mode of the microcontroller responsive to the color management reference value.
    Type: Grant
    Filed: December 18, 2007
    Date of Patent: September 2, 2014
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Keith J. Vadas
  • Patent number: 8651685
    Abstract: Provided are solid state backlight devices and methods for forming the same. A solid state backlight unit according to some embodiments of the invention includes a housing having a major surface and multiple LEDs on a first surface of the major surface. The solid state backlight unit also includes a specular reflector proximate to the first surface of the major surface and oriented substantially perpendicular to the first surface of the major surface.
    Type: Grant
    Filed: March 16, 2007
    Date of Patent: February 18, 2014
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Chenhua You
  • Patent number: 8556464
    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: May 31, 2011
    Date of Patent: October 15, 2013
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Paul E. Sims, Chenhua You
  • Publication number: 20130249408
    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 17, 2013
    Publication date: September 26, 2013
    Applicant: Cree, Inc.
    Inventors: John K. Roberts, Keith J. Vadas
  • Patent number: 8513871
    Abstract: Provided are methods and apparatus for combining light emitters and devices including the same. Embodiments include methods of selecting combinations of multiple light emitters that are grouped into multiple bins. The multiple bins correspond to multiple emitter group regions in a multiple axis color space and multiple luminosity ranges. Such methods may include prioritizing multiple combinations of light emitters from at least two of the bins, each of the combinations including chromaticity values corresponding to a desired color region and a luminosity value corresponding to a specified luminosity range.
    Type: Grant
    Filed: December 14, 2012
    Date of Patent: August 20, 2013
    Assignee: Cree, Inc.
    Inventors: Chenhua You, John K. Roberts
  • Patent number: 8514210
    Abstract: A method of calibrating a lighting panel including a plurality of segments, a respective segment configured to emit a first color light and a second color light in response to pulse width modulation control signals having respective duty cycles, includes activating the plurality of segments to simultaneously emit the first and second colors of light. A combined light output for the plurality of segments is measured at a measurement location to obtain aggregate emission data. Separate emission data for the first and second colors of light is determined based on the aggregate emission data. For example, the separate emission data for the first and second colors of light may be derived based on extrapolation of the aggregate emission data and expected emission data for the first and second colors of light. Related calibration systems are also discussed.
    Type: Grant
    Filed: May 21, 2007
    Date of Patent: August 20, 2013
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Chenhua You, Clinton Vllcans
  • Patent number: 8461776
    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: Grant
    Filed: May 11, 2012
    Date of Patent: June 11, 2013
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Keith J. Vadas, Muhinthan Murugesu
  • Patent number: 8456388
    Abstract: Provided are systems and methods for controlling a solid state lighting panel. A system according to some embodiments of the invention includes a first microprocessor operative to perform color management data processing and generate emitter control data values. The system also includes a second microprocessor operative to receive the emitter control data values from the first processor to control a plurality of light emitters.
    Type: Grant
    Filed: February 14, 2007
    Date of Patent: June 4, 2013
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Keith J. Vadas
  • Patent number: 8449130
    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: March 25, 2010
    Date of Patent: May 28, 2013
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Keith J. Vadas
  • Patent number: 8330710
    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: October 11, 2011
    Date of Patent: December 11, 2012
    Assignee: Cree, Inc.
    Inventors: John K. Roberts, Keith J. Vadas
  • Patent number: 8294075
    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: August 5, 2010
    Date of Patent: October 23, 2012
    Assignee: Cree, Inc.
    Inventor: John K. Roberts
  • 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