| 摘要 |
PURPOSE: A driving method of an image display device utilizing a pulse width modulation is provided to implement a various multiple gradation display with suppressing an increasing of consumption power. CONSTITUTION: An image display device employing a pulse width modulation(PWM) driving includes a plurality of pixel electrodes, a plurality of pixel switching devices individually connected to each of the pixel electrodes, a plurality of signal lines and a common electrode commonly connected to each pixel. A voltage being less than a voltage supplied to signal lines is applied to pixel electrodes. Tones are displayed by shifting phases of waveforms of the signal lines and scanning lines, and polarities of pixels in a signal line direction are inverted alternately. A curve obtained by charging the pixel from 0 V to 5 V is almost linear already, and the benefit of having further linearity is insignificant even when a range which corresponds to a charging rate lower than 80 percent is utilized. On the contrary, below 80 percent, a voltage at least 1.25 times (1/0.8=1.25) the voltage actually required to drive the liquid crystal is supplied to the signal line, and power consumption, which is proportional to the square of the voltage, is increased by 1.5 times or greater, resulting in adverse poor efficiency.
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