Inner fitting being done in

摘要

PROBLEM TO BE SOLVED: To provide a metal halide lamp with little color temperature change even after a long period of lighting and with continued stable characteristics by reducing the volume of luminous metal infiltrating into a gap inside a tubule part.;SOLUTION: An electrode pin 5b having an electrode coil 4b at its tip part is supported at an end part of the side of a discharge space 1 of an electrode- supporting body 6b sealed by a sealing material 7b at an outer end part of the tubule part 3b. A coil-shaped cylindrical boy 14 is extrapolated at the base end of the electrode pin 5b. Provided a lamp output is P (W), a distance from the end face of the tubule part 3b at the discharge space 1 side to the end part of the electrode coil 4b at the tubule part 3b side is X (mm), a length of the tubule part 3b extended from the end face of the discharge space 1 side toward the discharge space 1 side of the cylindrical body 14b is L (mm), the following relation is composed: X≥0.0056P+0.194, and 0≤L≤0.44X.;COPYRIGHT: (C)2004,JPO