| 摘要 |
PURPOSE:To quickly move an arc spot to the tip of an electrode even when it occurs at the base end of the electrode at discharge start and prevent the devitrification, leak, and electrode break of a luminous tube and then provide the captioned lamp with a long life by positioning the tip of the electrode within the specified angular range for the upper part. CONSTITUTION:Electrodes 21 and 21 are provided opposedly in a spherical luminous tube 1 made of quartz glass. The electrodes 21 and 21 are comprised by winding an electrode coil 23 around an electrode axis 22. In addition, the electrode axis 22 is bent upward and electrode tips 21a and 21a are positioned within the range of an angle theta=5 to 30 deg.. The angle theta forms an upward angle that is provided with the end of a sealing section as the vertical angle for a line O1 to O1 in which the ends of the sealing sections of both electrode electrodes 21 and 21. As a result, even when an arc is bent upward for horizontal lighting, since the electrode tips 21a and 21a are always in the arc path and the electrode tips 21a and 21a are heated by the arc and then thermal electrons are easily emitted, the arc spot is easily moved to the electrode tips 21a and 21a. |
