Patent attributes
As a display device has a higher definition, the number of pixels, gate lines, and signal lines are increased. When the number of the gate lines and the signal lines are increased, there occurs a problem that it is difficult to mount an IC chip including a driver circuit for driving the gate and signal lines by bonding or the like, whereby manufacturing cost is increased. A pixel portion and a driver circuit for driving the pixel portion are provided over the same substrate, and at least part of the driver circuit includes a thin film transistor using an oxide semiconductor interposed between gate electrodes provided above and below the oxide semiconductor. Therefore, when the pixel portion and the driver circuit are provided over the same substrate, manufacturing cost can be reduced.
