| 摘要 |
PURPOSE: To ensure that a discharge lamp is started, to simplify ground, to simplify installation work at low cost and to make improvement as to the problem of an electric shock, etc., by providing a discharge resistance, and controlling the supply of voltage to an ignitor so that it becomes discontinuous. CONSTITUTION: When a voltage is supplied from a power supply portion, an ignitor 4 is rectified and smoothed in a number of steps and its output is applied to a discharge lamp 3. A control means 14 controls the voltage supply to the ignitor 4 to make it discontinuous, so that even if the ignitor 4 is designed to output a voltage with a peak value of several KV, for example, its effective value is decreased. The period during which the voltage is supplied to the ignitor 4 is set so that the output voltage has a peak value and a width such that the lamp 3 can be started and shifted to a lighted state. After being lighted, the lamp 3 is stably kept lighted by the output from the power supply portion and via a discharge stabilization means 2. A discharge resistance 13 is connected in parallel with the capacitor 12 of the final stage, so that improvement can be made as to the problem of an electric shock, etc. |
