| 摘要 |
PURPOSE:To enable a luminous radiation electron tube to be attached directly to the flat surface of a ceiling or the like by installing an anode concentrically with a semicylindrical outer tube. CONSTITUTION:In a semicylindrical outer tube 21, a thermion-radiating bar-like cathode 22 is installed in such a manner as to be located almost in the center of the arc of the semicircular cross section of the outer tube 21. Besides a semicylindrical wire mesh anode 23 is installed in such a manner as to concentrically surround the cathode 22. Owing to the above constitution, a majority of the ultraviolet rays produced through excitation becomes incident upon a phosphor 25 existing on the round inner surface of the semicylindrical outer tube 21. The remaining part of the ultraviolet rays is scattered toward the flat inner surface of the tube 21 before being reflected by a reflecting film 26, and finally become incident upon the phosphor 25. Therefore it is possible to attach the luminous radiation electron tube to a flat surface. |
