| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a display device including a liquid crystal panel of a segment system, which decreases luminance of a backlight without impairing visibility of a liquid crystal screen. Ž<P>SOLUTION: A control circuit 11 acquires the luminance of external light from an optical sensor 12 and acquires the kind of power supply from a power supply discrimination circuit 25. The control circuit 11 uses these acquired information to determine a duty ratio of voltage for driving an LED 13 so that the duty ratio may become lower as the luminance of the external light gets higher, and the duty ratio may be higher when an AC power supply 21 is used than when a built-in battery 22 is used. Then, the control circuit sets transmittance of a segment included in the liquid crystal panel 15 so that the transmittance may become higher as the duty ratio gets higher. A transmittance control circuit 14 outputs voltage corresponding to the transmittance to the liquid crystal panel 15. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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