LIQUID CRYSTAL DISPLAY DEVICE AND DRIVING METHOD THEREOF

摘要

PURPOSE: A liquid crystal display device and an operating method thereof are provided to display an image in both a light reflecting mode and a light transmitting mode wherein the light reflecting mode uses external light as a light source and the light transmitting mode uses a backlight. CONSTITUTION: A first pixel transistor(16a) and a second pixel transistor(16b) have an oxide semiconductor layer. An off current of the transistor is very small wherein the transistor includes the oxide semiconductor layer. Therefore, capacitances of a first capacitor(17a) and a second capacitor(17b) get small. A transistor with a very small amount of off currents is used as the pixel transistor. A period during which a supply voltage to the second liquid crystal device is maintained is long.