| 摘要 |
PURPOSE:To prevent the deterioration in life of a discharge light, by setting an output frequency of an AC power supply device energizing the discharge light to a multiple of a product between a scanning frequency of a video signal and the number of stages of dimmer so as to mitigate the asymmetricity of the lamp current of the discharge light. CONSTITUTION:Discharge lights 11-1n are used as display elements, the discharge lights are energized with AC power supply devices 31-3n, and the output frequency of the AC power supply devices 31-3n is set to an integral multiple of the product between the scanning frequency of the video signal and the number of stages of dimmer. Thus, the AC voltage having an integral number of cycles is applied always to the discharge light 11-1n and the asymmetricity of the lamp current is decreased, allowing to attain the long life of the discharge lights. |
