| 摘要 |
PROBLEM TO BE SOLVED: To suppress the power consumption of a liquid crystal display device by controlling a voltage to be applied to a backlight device for the synchronizing period of the synchronizing signal lower than that in the other period. SOLUTION: When this device is set in a power-saving mode by a mode setting switch 20, a synchronous signal is inputted to a switching control circuit, and a switching control signal is outputted from the switching control circuit according to the synchronous signal. A transistor is controlled ON-OFF according to this switching control signal, and controls the supply of an operation voltage to a backlight 5 from a power source circuit 8. In the power-saving mode, since the transistor is ON for the period while the vertical synchronous signal is at the level H (video signal period), the operation voltage from the power source circuit 8 is applied to the backlight 5. Since the transistor is OFF for the period while the vertical synchronous signal is at the level L (synchronized period), the operation voltage from the power source circuit 8 is not applied to the backlight 5.
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