LOW-PRESSURE MERCURY LAMP AND METHOD FOR ASSEMBLING THE SAME

摘要

An arc tube (2) is formed by a glass tube that is turned at a substantially middle thereof and wound around a spiral axis (13) from the middle, preferably to have a double-spiral structure. End portions of the arc tube are wound around the spiral axis (13). A holder (6) has insertion openings (63, 64) formed therein in such shapes that correspond to shapes of the ends of the arc tube (2). The insertion openings allow the ends of the arc tube (2) to be inserted along a bottom wall of the holder (6). The holder preferably also includes guide grooves (66a, 67a) provided in the areas before the insertion openings (63, 64) in the spiral direction of the ends of the arc tube (2). The guide grooves (66a, 67a) allow the end portions of the arc tube (2) to come in contact, and when the arc tube is rotated around the axis (13), guide the ends of the arc tube (2) to the insertion openings (63, 64).