| 摘要 |
PURPOSE:To obtain a discharge lamp able to distribute lights to a determined direction effectively and also to enable the form of the reflecting plate to be designed freely by providing a reflecting plate between discharge space and non-discharge space. CONSTITUTION:A discharge lamp is constituted with an external tube 1 of cylindrical form forming an air tight space, concentric cylindrical internal tube 2 installed at the approximate center of the external tube 1 and a reflecting plate 3 installed between the external tube 1 and the internal tube 2, the same air tight space as that within the external tube 1 is built within the internal tube through the opening 4 provided on the internal tube 2, a pair of electrodes 5, 5 are disposed in the vicinity of both ends of the internal tube 2, inside of the internal tube 2 is made a discharge space A and the other space within the external tube 1 is made a non-discharge space B. And the external surface area of the external tube 1 Sb constituting non-discharge space B against the external surface area Sa of the internal tube 2 constituting discharge space A, is made to satisfy Sb>=5Sa, and main discharge (luminous) material is made of metal vapor. Index 6 as shown in the drawing are the holders to fix the internal tube 2 and the reflecting plate 3. |
