| 摘要 |
PROBLEM TO BE SOLVED: To provide a starter built-in type metal halide lamp in which the dispersion of a restart time is reduced, the characteristic deterioration of FEC is prevented, and starting is surely conducted even at a restart time. SOLUTION: A metal halide lamp is composed of an arc tube 1 which is equipped with one pair of main electrodes 2a, 2b, a starting auxiliary electrode 3 set in the vicinity of one side main electrode 2b, and a starter disposed in a lamp outer tube. In the lamp, the starter is composed of a series circuit of an FEC 5, which is connected between the main electrodes via a heat sensitive switch 4, and a semiconductor switch 6, first resistor 9 connected to the series circuit in parallel, second resistor 8 connected to the semiconductor switch 6 in parallel, and third resistor 7 connected between the starting auxiliary electrode 3 and the other main electrode 2a via the heat sensitive switch 4. The resistor values Re, Rs, Ra of the first, the second, and the third resistors 9, 8, 7 are set so as to meet following requirements. 10kΩ<=Rc<=100kΩ, and loge Ra >=1.19(loge Rs )<2> -24.6loge Rs +137. |
