Liquid crystal display device

A liquid crystal display device, comprising:

• a first substrate having a plate-shaped first common electrode, and a pixel electrode that is provided in a separate layer from the first common electrode with an insulating film therebetween, said pixel electrode having a comb-shaped structure;
• a second substrate facing the first substrate, said second substrate having a second common electrode;
• a liquid crystal layer sandwiched between the first substrate and the second substrate, said liquid crystal layer comprising liquid crystal molecules that have a negative dielectric anisotropy;
• a first control circuit that supplies an electric signal to the first common electrode;
• and
• a second control circuit that supplies an electric signal to the second common electrode,
• wherein a difference in potential between the electric signal supplied to the first common electrode and the electric signal supplied to the second common electrode is 10 to 20V.

A liquid crystal display device, comprising:

• a first substrate having a plate-shaped first common electrode, and a pixel electrode that is provided in a separate layer from the first common electrode with an insulating film therebetween, said pixel electrode having a comb-shaped structure;
• a second substrate facing the first substrate, said second substrate having a second common electrode;
• a liquid crystal layer sandwiched between the first substrate and the second substrate, said liquid crystal layer comprising liquid crystal molecules that have a negative dielectric anisotropy;
• a third control circuit that supplies higher frequency alternating current signals to the second common electrode;
• and
• a fourth control circuit.

A liquid crystal display device, comprising:

• a first substrate having a plate-shaped first common electrode, and a pixel electrode that is provided in a separate layer from the first common electrode with an insulating film therebetween, said pixel electrode having a comb-shaped structure;
• a second substrate facing the first substrate, said second substrate having a second common electrode;
• a liquid crystal layer sandwiched between the first substrate and the second substrate, said liquid crystal layer comprising liquid crystal molecules that have a negative dielectric anisotropy;
• a backlight unit;
• a backlight unit control circuit;
• a fifth control circuit that supplies alternating current signals to the second common electrode;
• a sixth control circuit that supplies alternating current signals to the pixel electrode, the fifth control circuit and the sixth control circuit supplying alternating current signals of the same frequency;
• and
• a control circuit that turns OFF the backlight unit in accordance with positive and negative switching of the alternating current signals by the fifth control circuit.