| 摘要 |
PURPOSE:To allow an applied voltage to a display part to be changeable, and to prevent the deterioration of a display element by suppressing in advance abnormal rise of the applied voltage, by providing an electrifying circuit inverting the directions of currents to each other, flowing a bias current to a voltage dropping means installed in the electrifying circuit. CONSTITUTION:Between a power source means and a display part 1, coloring use and decoloring use electrifying circuits by which directions of currents A, B flowing to a display element 1a are inverted to each other are provided separately. In the electrifying circuit, a voltage dropping means is also installed, and also, to the voltage dropping means, a bias current C is supplied. Also, in addition to the decoloring use current A, the bias current C is supplied, and even at the time of decreasing the decoloring use current A, a voltage drop value in the voltage dropping means is secured by the necessary minimum, and moreover, by changing a value of the bias current C, an applied voltage itself to the display part 1 can be changed. In such a way, in spite of the fluctuation of an electrifying current, the upper limit value of a voltage applied to the display element can be controlled, and the deterioration of the display element can be suppressed.
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