| 摘要 |
PURPOSE:To prevent any decrease of the efficiency and any insufficiency of the luminance of an electric discharge lamp by making a discharge-route restricting body, which divides the internal discharge space of the bulb into halves, to have an oval shape having an expanded part in its center, and providing an over plate, which works as a light emitting surface, on the discharge-route restricting body. CONSTITUTION:A pair of opposed electrodes 3 are provided at an end of a bulb 1, the inner wall of which is coated with a phosphor layer 2. After that, a discharge-route restricting body 4, which has an oval shape and the width of the central part of which is larger than that of its side part, is installed between the electrodes 3 so that a U-shaped discharge route, which has a crescent-shaped cross section and passes through the end of the bulb 1, is formed. In addition, an over plate 10 is affixed over the body 4, and a phosphor layer is formed on the plate 10 so as to make a light emitting surface. As a result, the efficiency of an electric discharge lamp is enhanced since the discharging part with a high current density can be made closer to the inner wall of the bulb 1. Besides, the luminance of the lamp can be enhanced by increasing light by the emission of the plate 10. |
