| 摘要 |
PROBLEM TO BE SOLVED: To reduce power consumption by correctly performing extinction of a backlight even in a near-stationary state.SOLUTION: A portable terminal device includes a touch panel (1) formed by laminating a display device (4) and a capacitance type position input device (3), and having a backlight (5) under the display device (4). In the portable terminal device, a capacitance detection unit (7) of a backlight control unit (6) detects capacitance of the position input device (3) on the basis of a position signal from the position input device (3); and a detected capacitance analysis unit (8) determines whether or not the display device (4) is browsed by a user on the basis of a state of change in the detected capacitance; and when the display device (4) is not browsed by the user, a backlight lighting and extinction signal generation unit (9) generates and outputs a backlight extinction signal to the backlight (5). Accordingly, even in a near-stationary state, it is accurately determined whether or not the display device (4) is browsed by the user, so as to turn off the backlight (5), and further reduce power consumption without using an acceleration sensor or the like. |
