Patents by Inventor Joji Oyama

Joji Oyama 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).

  • Discharge lamp lighting device
    Patent number: 6580229
    Abstract: A discharge lamp driving device capable of detecting a lamp life end reliably in a high or low temperature environment for circuit protection, yet preventing the occurrence of the cataphoresis phenomenon. Impedance elements Z1 and Z1 are inserted respectively between one filament ends of individual discharge lamps La1 and La2 and a node (the ground) having no high frequency amplitude in order to detect a difference between AC components of individual lamp voltages VLa1 and VLa2 in closed loops of the discharge lamps La1 and La2 and the impedance elements Z1 and Z1 in order to judge whether or not the depletion of the emitter occurs. Thus, it is possible to reliably judge the presence of abnormality even when the amplitudes of the lamp voltages VLa1 and VLa2 varies in a range of low to high temperature.
    Type: Grant
    Filed: February 14, 2002
    Date of Patent: June 17, 2003
    Assignee: Matsushita Electric Works, Ltd.
    Inventors: Yoshinobu Murakami, Joji Oyama, Toshiya Kanja, Shigeru Ido, Naokage Kishimoto
  • Discharge lamp lighting device
    Publication number: 20020105283
    Abstract: A discharge lamp driving device capable of detecting a lamp life end reliably in a high or low temperature environment for circuit protection, yet preventing the occurrence of the cataphoresis phenomenon. Impedance elements Z1 and Z1 are inserted respectively between one filament ends of individual discharge lamps La1 and La2 and a node (the ground) having no high frequency amplitude in order to detect a difference between AC components of individual lamp voltages VLa1 and VLa2 in closed loops of the discharge lamps La1 and La2 and the impedance elements Z1 and Z1 in order to judge whether or not the depletion of the emitter occurs. Thus, it is possible to reliably judge the presence of abnormality even when the amplitudes of the lamp voltages VLa1 and VLa2 varies in a range of low to high temperature.
    Type: Application
    Filed: February 14, 2002
    Publication date: August 8, 2002
    Inventors: Yoshinobu Murakami, Joji Oyama, Toshiya Kanja, Shigeru Ido, Naokage Kishimoto