| 摘要 |
PURPOSE:To turn on the back light source without fail even if a last setting of a dimmer is still employed when the liquid crystal display device is reused by supplying a DC input voltage which can turn on a fluorescent light discharge tube for back lighting without fail under any environmental condition to an inverter irrelevantly to the setting state of a DC input voltage control circuit. CONSTITUTION:The device consists of a DC input safety circuit 1, the DC input control circuit 2 for the inverter, an AC output circuit 3 including the inverter, a voltage boosting transformer, etc., and the fluorescent discharge tube 4. Then a high voltage which can turn on the fluorescent discharge tube 4 without fail even under bad environmental condition of low room temperature, etc., is applied while after the power source is closed regardless of the setting stat of a dimming means. Therefore, a sufficiently large discharging current flow to raise the temperature in an in-tube discharge path speedily and a stable turn-on and discharge state is entered in a short time without any unstable stat which is caused by a normal turn-on power source. Consequently, when the device is used next, the light source is turned on without fail even if the last setting of the dimmer is still unchanged. |
