| 摘要 |
PURPOSE:To realize a homogeneous luminance easily by providing a discharge- lamp supporting member in such a manner that it is coaxial with the rotationally symmetrical axis of a cavity wall; the supporting member influences upon the light path to a small extent, and the influence is rotationally symmetrical. CONSTITUTION:In order to facilitate initiation of the electric discharge of an electric-discharge lamp 6, a discharge-initiating auxiliary body 13 is buried inside the lamp 6. The outer surface of the lamp 6 is provided with a screw thread 6c which is fitted into the screw hole 14a of a supporting member 14. The projection 6b of the lamp 6 is fitted into the hole 14a so as to fix the lamp 6. In a device which is constituted in such a manner as above, since the supporting member 14 is provided in such a manner that it corresponds to the rotationally symmetrical axis of a cavity wall 4, light traveling outward through the mesh surface is hardly shut off directly. In addition, even if there is any influence on the light path, the influence always is rotationally symmetrical. As a result, the shape of the cavity wall 4 can be easily designed in such a manner that a homogeneous illuminance distribution is realized. |
