| 摘要 |
PURPOSE:To execute the luminance adjustment in a multistage and to eliminate flickering caused by a luminance fluctuation by a simple constitution by providing a light emission frequency control circuit for reading an output voltage level of a free running multivibrator by synchronizing with a horizontal synchronizing signal, and determining the discharge light emission frequency in one period of the horizontal synchronizing signal in accordance with whether the level is high or low. CONSTITUTION:As for a free running multivibrator 10, a duty factor of an output pulse is variable, and also, an oscillation period is 2 - 16ms. Light emission frequency control circuits 12, 18 read an output voltage level of the free running multivibrator 10 by synchronizing with a horizontal synchronizing signal, and determines the discharge light emission frequency in one period of the horizontal synchronizing signal in accordance with whether the level is high or low. That is, the duty factor of the free running multivibrator is variable, and an oscillation frequency of the free running multivibrator is set to 2 - 16ms. In such a way, the luminance adjustment can be executed in a multistage, and flickering caused by a luminance fluctuation can be prevented by a simple constitution. |
