| 摘要 |
<p>PURPOSE:To allow a cap to be fitted into a base to a specified depth without being interfered with adhesive agent filled inside the cap to ensure their coupling by covering a base side wall over outside a cap side wall. CONSTITUTION:A side wall 21 of a base 11 is formed with a larger diameter than a side wall 22 of a cap 12. After an arc tube 1 is joined to the cap 12 by adhesive agent 14 with a bulb 2 inserted into an insertion hole 15 of the cap 12, the side wall 21 is put over the side wall 22 and fitted to each other. The side walls 21, 22 are coupled with each other by engagement between a protrusion and a recess 23, 24. Insertion depth of the side wall 21 is regulated by a flange 25 of the cap 12. Thus even if a ceiling of the cap 12 is filled with a large amount of the adhesive agent 14, fitting between the base 11 and the cap 12 is not interfered, so that it is not necessary to adjust the amount of the adhesive agent 14 to be filled for ensuring tight junction of the arc tube 1 to the cap 12.</p> |
