| 摘要 |
PURPOSE:To properly decompose and activate alkaline earth metal carbonate adhered to a filament and to obtain a low pressure mercury vapor discharge lamp of high quality by making the inside of a bulb a rare gas atmosphere and by keeping the peak-to-rms ratio of an applied voltage at a specific value. CONSTITUTION:While a bulb is being discharged, a voltage with a peak-to-rms ratio of less than 1.7, e.g., sinusoidal wave (peak-to-rms ratio of about 1.4) is applied to a filament to make a current flow so that the carbonate adhered to the middle portion of the filament is decomposed and activated. Next, argon or the like is filled in the bulb at a pressure of, e.g., 0.5-50Torr, and the phase of the applied voltage is controlled so as to keep its peak-to-rms ratio at 1.7 or higher. Then, a local discharge is generated across both ends of the filament, thus heating both ends, and the carbonate adhered to the filament is decomposed and acivcated. Thereby, a low pressure mercury vapor discharge lamp of high quality can be obtained. |
