| 摘要 |
<P>PROBLEM TO BE SOLVED: To restrain a phenomenon in a long arc type discharge lamp having a pair of electrodes disposed oppositely in an arc tube and having mercury of 0.5 mg/cm<SP POS="POST">3</SP>or less and metal, such as iron, and halogen sealed therein that sealed-in metal is driven into the inside wall of the arc tube even when power is switched over frequently, thereby preventing an illuminance retention rate from being reduced in a short period of time. <P>SOLUTION: The present invention relates to a long arc type discharge lamp having a pair of electrodes disposed oppositely in an arc tube, in which the arc tube has mercury (Hg) of 0.5 mg/cm<SP POS="POST">3</SP>or less sealed therein, at least one kind of metal, e.g., iron (Fe), thallium (Tl) or bismuth (Bi), sealed therein, and halogen sealed therein, where, letting the substance amount of the sealed metal except mercury be M (mol) and the substance amount of the sealed halogen be H (mol), the ratio H/M is within the range 2.1≤H/M≤5.0. <P>COPYRIGHT: (C)2012,JPO&INPIT |
