| 摘要 |
PURPOSE: A device for automatically adjusting a backlight according to an external illuminance is provided to prevent unnecessary current consumption by automatically adjusting the brightness of the backlight using an LDR(Light Dependent Resistor). CONSTITUTION: A power unit(21) supplies a backlight power. A resistance value of an LDR(25) is varied according to an external illuminance. Current levels of LEDs(Light Emitting Diodes)(22,23) are adjusted according to a variable resistance value of the LDR. The LEDs adjust the supply quantity of the backlight power supplied from the power unit according to current quantity, and adjust brightness. A transistor(25) controls the on/off of the LEDs according to a backlight control signal.
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