| 摘要 |
PURPOSE:To enable the optical color of a luminous tube to be freely varied by preparing a phosphor from a blue phosphor with high excitation energy, a green phosphor with moderate excitation energy and a red phosphor with low excitation energy. CONSTITUTION:A thermion-emissive cathode 3 is installed in an inner area corresponding to the rivet of a glass tube 1 which has a fan-like cross section and forms a vacuum space 2. An anode 4 consisting of a transparent conductive film is formed on the inner surface of the spherical section of the glass tube 1. And, a phosphor 5 is applied to the above transparent conductive film. The phosphor 5 is prepared by mixing a blue phosphor with high excitation energy, a green phosphor with moderate excitation energy and a red phosphor with low excitation energy. As a result, when the input energy is increased from the low level to the moderate level, the color tone changes from red to white through orange, yellow and green. And, when the input energy is increased from the moderate level to the high level, the color tone changes from white to blue. |
