Patents by Inventor Johannes Antonius Kwakman

Johannes Antonius Kwakman 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).

  • Method and device for driving a multicolor light source
    Patent number: 8427079
    Abstract: A lighting device (1) comprises a plurality of LEDs (11-14) producing light (21-24) of mutually different colors. The LEDs are driven in switching cycles (63) with a duty cycle controlled supply current of constant magnitude. In each switching cycle, each LED is first switched ON (61) and then switched OFF (62). In a measuring mode, during one switching cycle (63B), all ON phases of all LEDs are briefly interrupted, except for one LED (11), so that a light sensor (70) measures the light from this one LED. This measurement can be used to adapt the duty cycle of this one LED. In the next switching cycle (63C), the interruption of the ON phases is compensated by extending the ON phases of all LEDs except said one LED, the extension having a duration equal to the duration (?D) of the interruption.
    Type: Grant
    Filed: August 28, 2009
    Date of Patent: April 23, 2013
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Geert Willem Van Der Veen, Johannes Antonius Kwakman
  • Method and device for driving a multicolor light source
    Publication number: 20110148315
    Abstract: A lighting device (1) comprises a plurality of LEDs (11-14) producing light (21-24) of mutually different colors. The LEDs are driven in switching cycles (63) with a duty cycle controlled supply current of constant magnitude. In each switching cycle, each LED is first switched ON (61) and then switched OFF (62). In a measuring mode, during one switching cycle (63B), all ON phases of all LEDs are briefly interrupted, except for one LED (11), so that a light sensor (70) measures the light from this one LED. This measurement can be used to adapt the duty cycle of this one LED. In the next switching cycle (63C), the interruption of the ON phases is compensated by extending the ON phases of all LEDs except said one LED, the extension having a duration equal to the duration (?D) of the interruption.
    Type: Application
    Filed: August 28, 2009
    Publication date: June 23, 2011
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N.V.
    Inventors: Geert Willem Van Der Veen, Johannes Antonius Kwakman