| 摘要 |
PURPOSE:To obtain a light controlling function by a simple circuit constitution by changing a modulation voltage by bringing a charge time to variable control by a control means, when a capacitor is charged with a power source current and a voltage which is superposed a power source voltage to its charge voltage is outputted as the modulation voltage. CONSTITUTION:The title display device is provided with a control means 28 for bringing a charge time of a capacitor 25 to variable control. In a modulation driving circuit 19, when an output means 27 charges the capacitor 25 with a power source current and a voltage which is superposed a power source voltage to its charge voltage is outputted as a modulation voltage, when the charge time of the capacitor 25 is brought to variable control, the charge voltage of the capacitor 25 changes in accordance with the charge time, therefore, in the end, the modulation voltage also changes, and brightness of a screen can be controlled thereby. In such a way, a light controlling function can be given at a low cost. |
