Patents by Inventor Tooru Ashikaga

Tooru Ashikaga 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).

  • Cold-cathode tube operating apparatus
    Patent number: 7034471
    Abstract: The present invention can provide a cold cathode tube lighting apparatus capable of causing no pulsating current, intermittent oscillation, or flicker-off even under light load, stably keeping a cold cathode tube lighting, safely tuning on the same, and the like. The present invention is characterized by supplying a rectangular wave voltage Vs to a series resonance circuit 12 and by driving the cold cathode tube 8 with an output of the series resonance circuit. The series resonance circuit has a constant that makes a maximum output voltage with respect to a predetermined tube current value exceed a tube voltage VL of the cold cathode tube when the cold cathode tube is turned on and in an operating load range of the cold cathode tube of negative resistance characteristic. A control circuit 15 controls a cold cathode tube current IL to a predetermined value while the cold cathode tube is in a lit state.
    Type: Grant
    Filed: March 17, 2003
    Date of Patent: April 25, 2006
    Assignee: Sanken Electric Co., Ltd.
    Inventors: Kengo Kimura, Tooru Ashikaga
  • Cold-cathode tube operating appratus
    Publication number: 20050088115
    Abstract: The present invention can provide a cold cathode tube lighting apparatus capable of causing no pulsating current, intermittent oscillation, or flicker-off even under light load, stably keeping a cold cathode tube lighting, safely tuning on the same, and the like. The present invention is characterized by supplying a rectangular wave voltage Vs to a series resonance circuit 12 and by driving the cold cathode tube 8 with an output of the series resonance circuit. The series resonance circuit has a constant that makes a maximum output voltage with respect to a predetermined tube current value exceed a tube voltage VL of the cold cathode tube when the cold cathode tube is turned on and in an operating load range of the cold cathode tube of negative resistance characteristic. A control circuit 15 controls a cold cathode tube current IL to a predetermined value while the cold cathode tube is in a lit state.
    Type: Application
    Filed: March 17, 2003
    Publication date: April 28, 2005
    Applicant: Sanken Electric Co., Ltd
    Inventors: Kengo Kimura, Tooru Ashikaga