| 摘要 |
PURPOSE:To increase the luminous efficiency of an electric discharge lamp, and prevent any leakage of sodium by lighting the lamp with a DC power source, and connecting an electrode located on the upper side during the lighting to the negative electrode side of the DC power source. CONSTITUTION:An upper electrode 2 which is located on the upper side during lighting, and a lower electrode 3 which is located on the lower side during lighting are charged in an emission tube 1, and are provided at the ends of the tube 1. The tube 1 is charged with appropriate amounts of mercury, argon, sodium iodide, thallium iodide, dysprosium and mercury iodide. A ballastless metal halide lamp is connected to a commercial AC power source 8 through a rectifying circuit 7, and is lit with direct current when it is in an approximately vertical state. The upper electrode 2 is connected to a negative electrode 9 side output terminal of the circuit 7. |
