Liquid crystal display device

A liquid crystal display device comprising:

• a pixel portion including a plurality of pixels each comprising:
• a transistor;
• a liquid crystal element including a pixel electrode, a common electrode, and a liquid crystal layer over the pixel electrode and the common electrode, wherein a first signal and a second signal having opposite polarities are alternately supplied to the pixel electrode through the transistor;
• and
• a first capacitor including a first electrode and a second electrode;
• and
• a circuit applying a potential to the second electrode, the potential configured to change between a first potential and a second potential after the first signal is supplied until the second signal is supplied,
• wherein the pixel electrode and the common electrode partly overlap with each other with an insulating film interposed therebetween, and
• wherein the first electrode is electrically connected to the pixel electrode.

A liquid crystal display device comprising:

• a first insulating film over a first conductive film and a second conductive film;
• a semiconductor film over the first insulating film, the semiconductor film overlapping with the first conductive film;
• a third conductive film and a fourth conductive film electrically connected to the semiconductor film, the fourth conductive film overlapping with the second conductive film;
• a second insulating film over the semiconductor film, the third conductive film, and the fourth conductive film, the second insulating film having an opening;
• a fifth conductive film over the second insulating film;
• a third insulating film over the fifth conductive film;
• a sixth conductive film over the third insulating film, the sixth conductive film overlapping with the fifth conductive film and electrically connected to the fourth conductive film through the opening;
• a first alignment film over the sixth conductive film and the third insulating film;
• a liquid crystal layer over the first alignment film;
• and
• a second alignment film over the liquid crystal layer,
• wherein a first signal and a second signal having opposite polarities are alternately supplied to the third conductive film, and
• wherein a potential configured to change between a first potential and a second potential is applied to the second conductive film.