| abstract |
An outer tube (2) and a lamp base (5) are sealed to each other with a sealing material (4). A current supply member (3) is inserted through the lamp base (5), and is fixed to the lamp base (5) with the sealing material (4). An exhaust tube (6) is inserted through the lamp base (5), and is fixed to the lamp base (5) with the sealing material (4). nAn electric discharge container is placed inside the outer tube (2). The sealing material (4) includes 35 to 75 vol% of a glass powder and 25 to 65 vol% of a refractory filler powder, and has a thermal expansion coefficient of less than 70×10 -7 /°C. The glass powder includes, as a glass composition, in terms of mass%, 55 to 85% of Bi 2 O 3 , 5 to 20% of B 2 O 3 , 1 to 15% of ZnO, and 0 to 7% of SiO 2 . |