| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp emitting light with the higher color temperature and having the higher luminous efficiency and the higher luminous flux maintenance factor.SOLUTION: A discharge lamp 100 includes: a light-emitting unit 11 internally having a discharge space 111 containing a metal halide; and a pair of electrodes 32 protruding to the inside of the discharge space 111 and disposed opposite to each other with a predetermined distance therebetween. The metal halide includes indium halide, sodium halide, and scandium halide. The following expressions are satisfied: 0.7≤N/S≤1.2, 0.04≤I/W≤0.15, and 0.3≤S/W≤0.45, in which the weight of the metal halide is W (μg), the weight of indium halide is I (μg), the weight of sodium halide is N (μg), and the weight of scandium halide is S (μg).SELECTED DRAWING: Figure 1 |
