| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a long arc type discharge lamp that comprises: an arc tube with a pair of electrodes therein; a seal part with metal foil buried therein: a supporting cylinder inserted into and welded to the seal part with the electrodes inserted through the supporting cylinder to support the electrodes; and a luminescent material of metal sealed in the arc tube; and that has a structure which prevents intrusion of metal vapor in the arc tube into a micro gap between the supporting cylinder and the electrodes, thus achieving a high illuminance maintenance ratio without erosion of the metal foil for an extended period of time. <P>SOLUTION: An end of the supporting cylinder, which is on the arc tube side, protrudes into a light emitting space of the arc tube such that some of the outer surface of the end is not welded to the seal. <P>COPYRIGHT: (C)2012,JPO&INPIT |
