| 摘要 |
PROBLEM TO BE SOLVED: To delay a deformation speed of an electrostrictive phenomenon caused by discharge of a ferroelectric ceramic capacitor at dielectric breakdown between electrodes of a light-emitting tube to prevent a breakage accident of the ferroelectric ceramic capacitor.SOLUTION: To an initiation circuit (4) housed and arranged in an outer tube (2) of a metal halide lamp (1) while being connected in parallel with a light-emitting tube (3), a ferroelectric ceramic capacitor (13), a semiconductor switch (15), and a time constant adjustment resistor (14) are connected in series. The ferroelectric ceramic capacitor (13) gives rise to charge and discharge when voltage equal to or more than a preliminarily set anti-voltage is applied, and makes a stabilizer output a high-voltage initiation pulse. The semiconductor switch (15) is switched to a conduction state when voltage equal to or more than a preliminarily set break-over voltage is applied. The time constant adjustment resistor (14) delays a discharge time of electric charge discharged from the capacitor at dielectric breakdown of the light-emitting tube. |
