| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp having passing arcs and a travelling arc formed in one sealed body. SOLUTION: An electrode located near one end consists of two primary electrodes, a travelling primary electrode 2a for forming a travelling arc and an? passing arc primary electrode 2b for forming passing arcs. A secondary electrode located near the other end is a secondary electrode 2c in common with the travelling primary electrode and the passing arc primary electrode. A buffer gas is a rare gas and a filler contains a metal halide. The wall thickness (t) of the sealed body (a luminescent tube), the inner diameter D of the sealed body (the luminescent tube) in a middle between the electrodes, a distance dH between the ends of the primary-distribution primary electrode and the secondary electrode, a distance dL between the ends of the secondary-distribution primary electrode and the secondary electrode, and distances lH, lL, l which the primary-distribution primary electrode, the secondary-distribution primary electrode and the secondary electrode are respectively protruded into the sealed body (the luminescent tube) are newly specified. A primary-distribution arc and a secondary-distribution arc are illuminated while switching one with the other in one sealed body (the luminescent tube). |
