Japan's First Triode

John Ambrose Fleming invented diodes in 1904, Lee De Forest invented triodes in 1907, and in 1913, Irving Langmuir completed hard valves.

Those had been big steps for the progression of the vacuum tube industry.
Tokyo Electric Co., Ltd. (the predecessor of our company), based upon vacuum technology mastered by the incandescent bulb production and its equipment, started research on vacuum tubes in 1916 and completed Japan's first triode (the Audion) the following year.