| 摘要 |
PURPOSE:To remove blackening material deposited on the external circumference at the center of light emitting tube in order to improve light flux by lighting a luminous tube of both ends are sealed with a closing material supporting electrodes while the external circumference at the center thereof is heated. CONSTITUTION:A blackening material 9 based on splash of emitter during the heating and sealing process for the ends of luminous tube 1 is deposited almost to the entire part of light emitting tube 1. Next, a heat retaining body 10 consisting of metal material of niobium is wound only to the external circumference at the center of luminous tube 1 for the area between the electrodes 4a, 4b, namely for the arc length. Moreover, the luminous tube 1 is lit by applying a voltage between electrodes 4a, 4b within a hermetically sealed case such as a belljar which is vacuumed or filled with inactive gas in order to prevent oxidation of current introducing bodies 7a, 7b made of niobium. When the luminous tube 1 lights for 30min or about 2hr, the blakening material 9 deposited to internal surface at the center of luminous tube 1 moves toward the ends of luminous tube 1 and it little exists at the center of luminous tube 1, thereby improving light flux. |
