| 摘要 |
PURPOSE:To prevent any scattering and disappearance of sodium amalgam during manufacturing and maintain the coldest temperature during lighting by sealing the ends of a light-transmitting ceramic tube by means of sealing members which support electrodes, and providing a radiation-heat-shielding member between the upper electrode and the sealing member. CONSTITUTION:An emission tube 3 charged in an outer tube 1, is made by airtightly sealing the end openings of a transparent ceramic tube 7 by means of sealing members 8a and 8b with an adhesive 9 interposed. Electrode supporters 10a and 10b are fixed to the sealing members 8a and 8b. They support electrodes 13a and 13b each formed by winding an electrode coil 12. A radiation-heat-shielding member 15 having a hole 14 in its center and its outer periphery is adjacent to the inner circumference surface of the tube 7, is attached through a tongue piece 16 to an electrode holder 11 located between the sealing member 8a and the coil 12 of the upper electrode 13 which is positioned on the upper side during lighting. By such a way as mentioned above, the tube 7 and the sealing member 8a are fused in the early manufacturing process. Sodium amalgam 17 is thrown over the sealing member 8a along the arrow so as to prevent any scattering or disappearance of the amalgam 17 which might be caused due to heating carried out in fusing the sealing member 8b to the end of the ceramic tube 7. |
